Why Is a Dental Crown Needed?

Artificial crowns.

Cast and combinated crowns.

 

Indications

1. The only option remaining.

2. Usually reserved for molar and lower premolar teeth.

3. Flame-shaped diamond

4. Excavator

Procedure

If the problem is such that a partial crown will not function, the only option is the full crown restoration, and it is the treatment court of last appeal. Full crowns are most frequently placed on molar teeth and occasionally on lower bicuspids.

The situations that require a complete crown include teeth that have exten­sive but questionable restorations or extensive carious involvement. A significant contributor to this difficulty is a large defective Class V amalgam restoration, and the only way a casting will perform is to make a complete crown. Another situation requiring this type of crown is presented by teeth that are very short and do not provide resistance unless a full crown is utilized.

Many times the locations of the gingival margins are predetermined by the existing restoration or caries and decalcification that must be enclosed. This often dictates that these margins, with emphasis on the interproximal and facial, will be in the gingival sulcus. If adequate resistance for the restoration and effec­tive coverage can be met without placing the margin in the sulcus, that is the rec­ommendation. Many times the lingual surface will be intact and it is easy to ter­minate the margin above the level of the gingiva, which eases the maintenance problems of the marginal gingiva.

The initial procedure is the occlusal reduction. The reduction may be done using a wheel diamond or a tapered round-end diamond. The same amount of reduction is required as for other posterior teeth, with a minimum of 1 mm wherever function occurs. The occlusal reduction should show correlation with occlusal morphology of the tooth and not be an arbitrary flattening of the occlusal surface.

Followin;g the occlusal preparation, proceed to the buccal and lingual reduction. A tapered round-end diamond is useful for this purpose. The gingival finish line will have been predetermined by the needs of retention, defective restorations, or caries. The reduction should reflect a chamfer effect at the gingi­val cavosurface. The buccal and lingual morphology is observed, and the reduc­tion is done to produce an even thickness of metal in the completed restoration consistent with the shape of the tooth.

The buccal and lingual walls are structured to provide good resistance to displacement. There is a danger of over-angulating the walls and losing the potential resistance for the casting. This reduction is carried toward the adjacent teeth. To avoid overcutting at the interproximal, a thin flame-shaped diamond is selected.

The finish line must be located gingival to the contact and be on healthy enamel. If an amalgam core or restoration  is part of the prepa­ration, it is expected that the finish line for the casting will terminate gingival to the restoration. The proximal walls must relate to each other in the same man­ner as to the buccal and lingual to provide optimal resistance. They will be slightly inclined toward each other.

This should complete most of the reduction, and now with a fine grit fin­ishing diamond or a No. 1170 bur the preparation is made smooth. All sharp corners or angles are slightly rounded. For some of the smoothing it is best that the bur run at a reduced speed to avoid excess cutting.

The occlusal clearance is checked in the same manner as discussed for previous posterior cast preprations.

Consideration must be given to clearance when the patient goes through eccentric movements, and the preparation must have adequate reduction to allow the restoration to have a acceptable function in all movements. This information must be placed into a suitable articulator to allow for a reliable wax-up and casting.

The final segment of the preparation is the placement of a groove on the buccal surface, and usually this will be in the anatomical buccal groove. This groove is of value, as it helps to provide positive orientation during the placement of the casting. It will tend to limit the potential for slight rotation of the crown during seating, as the groove will guide or key it into the specific placement. At times it will prove of value by providing a degree of supplemental retention, which may be helpful to a restoration with marginal retention. On occasion when the buccal segment of the tooth is badly destroyed this groove may be placed on the lingual portion of the preparation. If the preparation  requires a pin-supported amalgam or resin buildup, the groove may be placed m the amalgam or resin.

This groove may be formed by using a thin, tapered round-end diamond, or a No. 171 bur may be used effectively for this purpose. If the bur is used, it is advised to use it at reduced speed to avoid overcutting. This groove extends just short of the gingival finish line.

Resume of Partial and Full Crown Preparation

1. Gingival finish line when possible should be located occlusal to the gingiva.

2. Grooves with adequate length are preferred over proximal boxes for resistance form.

3. Do not terminate a finish line through a wear facet.

4. Occlusal reduction should occur first using wheel or football-shaped diamond. With a wax bite check for a minimum clearance of 1mm.

5. Lingual reduction with bullet-nose diamond 2D-T.

6. Interproximal reduction with thin or flamed-shaped diamond to avoid cutting adjacent tooth.

7. Proximal grooves are located for maximum length and will line up toward the buccal cusp tip.

8. Place buccal bevel toward facial to complement esthetics and function.

9. A V-shaped connector may be used between grooves.

10. With a seven-eighths crown one groove is located on the facial surface.

11. For a full crown preparation the facial reduction is done with the same instrument as for the lingual. A definite chamfer is needed for the buccal finish line.

12. Place a groove on the facial surface of the preparation for positive seating and use of tapered diamond or a No. 171 bur.

 

THE ABRASIVES

In the manner that all forms of prostheses require thorough and complete (to mirror brightness) polishing, some of the important auxiliary materials become abrasives – means for the polishing of prostheses. First prosthesis is ground, then they polish with the aid of the abrasives (from Lat. abrazio – erasure).

Abrasives can be before the powder, they can be before the bound state.

As bonding agents are used:

– Ceramic:mixture from the clay, the feldspar, the talc, the quartz. They are high-strength, thermally stable, moisture proofed.

– Bakelite: on the basis of the pasting Bakelite, natural rubber and other well elastic, high-impact.

– Vulcanite: on the basis of the vulcanized natural rubber with the gray (30%). Highly resilient, water-resistant, high-strength.

 All abrasives are divided:

1. Natural, that are encountered before nature.

2. Artificial,obtained by chemical means.

Natural

Diamond– most solid mineral. They use for preparing of separator discs and grindstones.

Corundum– before nature in the form of aluminum oxide. For preparing the grindstones. Distinguish the powder of №10, 20, 30 and so forth

Emery –in the form of the rock, contains corundum, oxide of iron and others make polishing paper and fabrics. It is divided about the numbers.

Pumice –volcanic origin: 70% of silica both oxides of metals and giving to it different painting.

Artificial

Carborundum –alloy: 36 h. fluxes before the electric furnace with 2000°[S]of the mixture 30% coke, 52% of quartz sand, 10% of sawdust, 2% of chloride sodium. Has crystalline structure. For preparing of grindstones, disks.

Electrocorundum –is obtained via the melting of bauxite with the coke before the electric furnaces. Very hard, thermo resistant. For the stones, the disks.

Pumice and emeryuse in the form aqueous pulp.

 The thinnest layer of surface is removed with the polishing. Polishing pastes are used for this.

            Basis of the pastes:

– Oxide of chromiumsolid, fine powder of green color, they obtain tempering bichromate potassium and sulfur = 5: 1.

Before the composition of paste GOI: 81% oxide of chromium, 2% silica gel, 10% stearin, 5 % fat, 2% kerosene. They divide beside the rough, the average, the thin. For the polishing of steel.

– Iron oxide– is obtained with interaction of iron vitriol and oxalic acid. They do not use for steel since are decreased anticorrosive properties.

– Mel– for the polishing of metals and plastics.

– Oxide of tin– for the polishing of porcelain.

 

Into the composition of pastes, besides abrasives enter the surface-active and binding agents (stearin, paraffin, wax, fat, vaseline). Pastes are brought down the circles, the cones from the skin, the felt, the fabric, the bristle, the hair and the threads.

Abrasive tools are characterized:

1. by birth abrasive (E – electrocorundum; E corundum is natural; KC – carborundum is black; KZ – carborundum is green)

2. with number of granularity (№10- 320 – powders; №28 – 45 – micropowder)

3. of hardness (ES – extremely soft, VS – very soft, S – soft, MS – middlesoft, H – medium-hard, SD–  solid, HS – very solid, EH – extra-hard)

With the work with different materials it is necessary to select different hardness cutting tools. With the large difference of the hardness of material and cutting tool the stone ceases to cut, cavities are driven in by shaving. The premature wear of stone occurs with the smaller hardness of stone. Stone before the process of work must gradually be destroyed in order to free the underlying grains of abrasive, they are not oppressed by shaving. The greater the speed, the less must be its hardness.

CHILLS

 As a result the heat working of the components (of metallic) prostheses occurs interaction of metal with the atmospheric oxygen, which leads to the formation of oxide film. The film worsens grinding and polishing of prostheses, it is capable of causing poisoning organism. Descaling is accomplished by the chemical reagents. Film hampers the soldering of components due to worsening in the interdiffusion of metals. The removal of oxide film is produced for the sake of chills.

As the chills the solutions of acids are used.

Hydrochloric acid. (HCl) – in air separate the hydrogen chloride (fuming acid). For the bleaching of gold (crown with the presence of the remainders of fusible alloy during the upholstering they are destroyed). 40% aqueous solution is used. Article is heated red hot, and then they lower beside the vessel with the solution of hydrochloric acid and in 1-2 min. they extract; they wash. Work based on HCl only in the exhaust hood.

Sulfuric acid.Colorless, oily liquid. They use for the bleaching of silver, it enters into the composition of electrolytes.

 Nitric acid.Colorless, smoking liquid with the sharp smell. Are dissolved all metals, except gold and platinum. Mixture from 30% – nitric acid and 60% hydrochloric acid “aqua regia” – for the dissolution of gold and platinum with the refining. Chills for the stainless steel:

FLUXES

For the removal of oxides and protection of articles from oxidation before the process of soldering use the fluxes (fluxes), capable of dissolving oxide film and in this case of surfacing of solder.

Requirements at the point of the fluxes:

1. the melting point of flux must be lower than the melting point of solder,

2. it must dissolve oxide film,

3. it is good to spread by means of the surface of article before the hot state,

4. not to volatilize before the process of soldering,

5. weld face after soldering.

Borax– the colorless crystals, water-soluble and glycerin of t° of 700-740°C is brought down the heated parts of the components. The remainders of borax based on the surface of prosthesis with the aid of the acids are moved away.

Boric acid.Colorless crystals, are dissolved before alcohol and water. Application before the combination with the brown and oxide of silicon is effective. Rosin.

THE INSULATION

Isocol– alginate separating material, used for preventing the entry of gypsum beside the plastic before the polymerization. Composition: alginate 1,5-2,0%, salt of aluminum 0,02, 40% solution of formalin – 0,3; dye food 0,005%; distillate water 98,0%. They bring down the model by brush beside 2 layers. Layer must be thin and uniform.

Moldin– mixture of the kaolin for the sake of the glycerin, elastic mass, is packed on250 g. They use during casting of the combined models, during casting of the combined models, with the production of crowns by the method of external stamping.

Varnish of cover “Eudes”.It adapts for masking the metallic parts of the prostheses; composite from the acrylic copolymers and the epoxy resin. It possesses grow prettier by permeability to the metal and the plastic.

MELOT

For creating of the stamped crowns and similar constructions is required the manufacture of dies. For this purpose adapt special fusible alloys on the basis of lead – Melot.   These alloys, besides low (70-95^oC) melting point, have a sufficient hardness, insignificant thermal contraction.

Into the composition of Melot enter tin, lead, bismuth (it fulfills role “of the extinguisher” of shrinkage), cadmium. Alloy is mechanical mixture.

With the work with the alloy one should remember that it cannot be overheated. This leads down the combustion of alloy, it makes for the sake of its more brittle, the shrinkage (it burns bismuth) increases. In addition to this, with the intensive heating are separated the vapors of cadmium, which are toxic for the organism.

Is also inadmissible entry down the surface of Melot of gold and platinum – they are connected for the sake of lead and bismuth, disrupting the structure of the latter.

The most beautiful crown for a tooth is, without question, all-porcelain or all-ceramic. With porcelain fused to metal crowns, there has to be an opaque layer put over the metal to block out its color. This makes it impossible to have a translucent restoration that mimics the translucency of natural teeth. Only with pure porcelain or pure ceramic can you have such translucency. To define some terminology, porcelain is a particular type of ceramic that is built by stacking and firing. When we say ceramic, we include porcelain—porcelain is a type of ceramic. The reason all dentists don’t use all-porcelain crowns for front teeth is that the technique for placing them is very demanding and isn’t generally taught in dental schools. They are translucent, and their color is influenced by the color of the underlying teeth. General dentists aren’t usually very skilled at color manipulation in these situations. Also, placing them requires the use of sophisticated bonding techniques that aren’t fully taught in dental schools. At mynewsmile.com we recommend that if you want one of these beautiful crowns for your front tooth, have it done by an expert cosmetic dentist such as we have listed on our site.        The crown is on the patient’s left lateral incisor, the smaller tooth just to the right of the two larger front teeth in our photograph.   Ceramic crowns 12, 11, 21, 22   The work was done by Dr. Duane Delaune, of Metairie, Louisiana. Notice how closely it mimics the appearance of the natural teeth.  CHOICES IN ALL-PORCELAIN AND ALL-CERAMIC CROWNS There are various types of all-porcelain or all-ceramic crowns. Let’s explain the differences between some of them:     Feldspathic porcelain is the standard, traditional porcelain that is used for crowns. Many cosmetic dentists feel that this is the most beautiful porcelain.     The Empress crown – Empress is strictly speaking not a porcelain, but is more like a glass. It can be called a ceramic material. The Empress material is cast rather than baked as a feldspathic porcelain crown is. The fit of Empress is more precise than the baked feldspathic porcelain. However, the color in Empress is mostly baked on the outside. Empress can be very beautiful. For appearance’s sake, some expert cosmetic dentists prefer the feldspathic porcelain, and some prefer the Empress.     The Procera crown – Procera is a milled ceramic on the inside with a more traditional porcelain baked onto the outside. The advantage of Procera is its exceptional strength. However, the milled ceramic core is opaque white, so many cosmetic dentists feel that it isn’t as natural-looking as the more translucent materials. An advantage of Procera is that it doesn’t have to be bonded to the tooth but can be cemented with ordinary crown and bridge cement, a technique familiar to all dentists.     The Lava crown – Lava is similar to Procera, but the milled ceramic on the inside is a more translucent Zirconia, rather than an opaque white material. The Zirconia is shaded, and then the final esthetics of the crown are achieved in the baked-on outer layer. The Lava crown can also be cemented with traditional techniques. However, any crown cemented with a traditional crown and bridge cement is going to be susceptible to a compromise in the appearance if that cement line ever shows.        Zirconia crowns, if they are done right, can be translucent enough to look natural. And if they are bonded to the teeth, instead of being cemented with conventional dental cement, they won’t show a black line at the gumline.     The Cerec crown – Cerec is are also milled from a block of very hard ceramic material. What’s unique about Cerec is that the crown is milled by a computer in the dentist’s office rather than in a separate dental laboratory. Thus, the dentist doesn’t have to send out for it to be made—it can be made on the spot. So, no second appointment is required, and no wearing of a temporary crown between appointments. Cerec is milled from a block of ceramic that is a single color, so it is generally not considered esthetic enough for demanding cosmetic dentists. A few exceptional dentists who are artists, however, are able to custom stain Cerec for front teeth so that they are truly beautiful. Some even make Cerec veneers that can be placed the same day. To be precise, Cerec is actually a technique and not a material. There are several companies that make ceramic materials for use in Cerec machines.     The InCeram crown – InCeram is made of a very dense and very tough aluminous porcelain. It also has excellent esthetics, but is more opaque than feldspathic porcelain. InCeram is also strong enough to be cemented with traditional dental cement.     There are other types of all-ceramic crowns. We’re not going to list all of them here.       ADVANTAGES AND DISADVANTAGES OF ALL-PORCELAIN AND ALL-CERAMIC CROWNS Let’s compare all-porcelain with porcelain fused to metal.     All-porcelain is generally not as strong as porcelain fused to metal. It has to be bonded to the tooth in order to have adequate strength for oral function. The bonding technique is very demanding and is not fully taught in dental schools. We recommend that you only have an expert cosmetic dentist place this type of crown.     With porcelain fused to metal, the porcelain has to be opaque in order to block out the appearance of the metal underneath. They all also eventually develop an unsightly dark line at the margin where the edge of the crown meets the tooth.     Some of the all-ceramic systems that have an inner ceramic core with an outer layer of porcelain baked on require more tooth reduction. Grinding away more of the tooth is ofteot desirable.     Some of the ceramic materials that are very tough and fracture resistant are also quite abrasive against the opposing teeth. Of the crowns listed above, the Empress is the kindest to the teeth it chews against.     GENERAL RECOMMENDATIONS FOR ALL-CERAMIC CROWNS        There are several factors that need to go into the selection of a crown material: strength requirements, esthetic requirements, the abrasivity of the material against the opposing teeth, and the skills of the dentist. There is not a single crown that is clearly superior for all situations. Many cosmetic dentists will have several types that they will use, each for a different situation.     It is generally a poor idea for a patient to go to a dentist and request a specific type of all-porcelain or all-ceramic. We have received many e-mails from patients who have done this and have been very disappointed with the results, because they were pushing their dentist to use a material the dentist was not comfortable with, and many dentists will try very hard to conceal from patients any discomfort they feel with a procedure. There is also the factor of the dental ceramist, whom you will most likely never meet. The material that is used for the crown should be intimately familiar to the dentist and to the ceramist for the best results.     You cannot learn, as a patient doing online research, which crown is best. First of all, there simply isn’t one all-ceramic material that is always best. Second, in a web page such as this, we can’t list all the properties of all them. Third, in evaluating these crowns, there is a great deal of background informatioeeded in order to evaluate which research claims are fully established and which claims should be questioned.     Our recommendation, at mynewsmile.com, is that you find a cosmetic dentist you can trust and that understands your needs and is passionate about creating beautiful dentistry. Then ask that expert cosmetic dentist to use the technique that he or she is most comfortable with in creating the all-ceramic crown that will be best for you. The choice of the material is secondary to the skills of the dentist and of the ceramist in working with that particular material. There are subtleties in working with all of these all-porcelain and all-ceramic materials that need to be mastered by the dentist and the ceramist to produce the most beautiful result.

Ceramic crown on 22 tooth

 

Ceramic crown on 11 tooth

  

 

 

 

 

 

Why Is a Dental Crown Needed?

A dental crown may be needed in the following situations:

1.     To protect a weak tooth (for instance, from decay) from breaking or to hold together parts of a cracked tooth

2.     To restore an already broken tooth or a tooth that has been severely worn down

3.     To cover and support a tooth with a large filling when there isn’t a lot of tooth left

4.     To hold a dental bridge in place

5.     To cover misshapened or severely discolored teeth

6.     To cover a dental implant

 

What Types of Crowns Are Available?

Permanent crowns can be made from all metal, porcelain-fused-to-metal, all resin, or all ceramic.

         Metals used in crowns include gold alloy, other alloys (for example, palladium) or a base-metal alloy (for example, nickel or chromium). Compared with other crown types, less tooth structure needs to be removed with metal crowns, and tooth wear to opposing teeth is kept to a minimum. Metal crowns withstand biting and chewing forces well and probably last the longest in terms of wear down. Also, metal crowns rarely chip or break. The metallic color is the main drawback. Metal crowns are a good choice for out-of-sight molars.

         Porcelain-fused-to-metal dental crowns can be color matched to your adjacent teeth (unlike the metallic crowns). However, more wearing to the opposing teeth occurs with this crown type compared with metal or resin crowns. The crown’s porcelain portion can also chip or break off. Next to all-ceramic crowns, porcelain-fused-to-metal crowns look most like normal teeth. However, sometimes the metal underlying the crown’s porcelain can show through as a dark line, especially at the gum line and even more so if your gums recede. These crowns can be a good choice for front or back teeth.

         All-resin dental crowns are less expensive than other crown types. However, they wear down over time and are more prone to fractures than porcelain-fused-to-metal crowns.

         All-ceramic or all-porcelain dental crowns provide the best natural color match than any other crown type and may be more suitable for people with metal allergies. However, they are not as strong as porcelain-fused-to-metal crowns and they wear down opposing teeth a little more than metal or resin crowns. All-ceramic crowns are a good choice for front teeth.

         Temporary versus permanent. Temporary crowns can be made in your dentist’s office whereas permanent crowns are made in a dental laboratory. Temporary crowns are made of acrylic or stainless steel and can be used as a temporary restoration until a permanent crown is constructed by the dental laboratory.

          

What Steps Are Involved in Preparing a Tooth for a Crown?

Preparing a tooth for a crown usually requires two visits to the dentist — the first step involves examining and preparing the tooth, the second visit involves placement of the permanent crown.

First Visit: Examining and preparing the tooth.

At the first visit in preparation for a crown, your dentist may take a few X-rays to check the roots of the tooth receiving the crown and surrounding bone. If the tooth has extensive decay or if there is a risk of infection or injury to the tooth’s pulp, a root canal treatment may first be performed.

Before the process of making your crown is begun, your dentist will anesthetize (numb) your tooth and the gum tissue around the tooth. Next, the tooth receiving the crown is filed down along the chewing surface and sides to make room for the crown. The amount removed depends on the type of crown used (for instance, all-metal crowns are thinner, requiring less tooth structure removal than all-porcelain or porcelain-fused-to-metal ones). If, on the other hand, a large area of the tooth is missing (due to decay or damage), your dentist will use filling material to “build up” the tooth to support the crown.

After reshaping the tooth, your dentist will use impression paste or putty to make an impression of the tooth to receive the crown. Impressions of the teeth above and below the tooth to receive the dental crown will also be made to make sure that the crown will not affect your bite.

The impressions are sent to a dental laboratory where the crown will be manufactured. The crown is usually returned to your dentist’s office in 2 to 3 weeks. If your crown is made of porcelain, your dentist will also select the shade that most closely matches the color of the neighboring teeth. During this first office visit your dentist will make a temporary crown to cover and protect the prepared tooth while the crown is being made. Temporary crowns usually are made of acrylic and are held in place using a temporary cement.

Second Visit: Receiving the permanent dental crown.

At your second visit, your dentist will remove your temporary crown and check the fit and color of the permanent crown. If everything is acceptable, a local anesthetic will be used to numb the tooth and the new crown is permanently cemented in place.

Because temporary dental crowns are just that — a temporary fix until a permanent crown is ready, most dentists suggest that a few precautions be taken with your temporary crown. These include:

         Avoid sticky, chewy foods (for example, chewing gum, caramel), which have the potential of grabbing and pulling off the crown.

         Minimize use of the side of your mouth with the temporary crown. Shift the bulk of your chewing to the other side of your mouth.

         Avoid chewing hard foods (such as raw vegetables), which could dislodge or break the crown.

         Slide flossing material out-rather than lifting out-when cleaning your teeth. Lifting the floss out, as you normally would, might pull off the temporary crown.

What Problems Could Develop With a Dental Crown?

         Discomfort or sensitivity. Your newly crowned tooth may be sensitive immediately after the procedure as the anesthesia begins to wear off. If the tooth that has been crowned still has a nerve in it, you may experience some heat and cold sensitivity. Your dentist may recommend that you brush your teeth with toothpaste designed for sensitive teeth. Pain or sensitivity that occurs when you bite down usually means that the crown is too high on the tooth. If this is the case, call your dentist. He or she can easily fix this problem. 

         Chipped crown. Crowns made of all porcelain can sometimes chip. If the chip is small, a composite resin can be used to repair the chip with the crown remaining in your mouth. If the chipping is extensive, the crown may need to be replaced.

         Loose crown. Sometimes the cement washes out from under the crown. Not only does this allow the crown to become loose, it allows bacteria to leak in and cause decay to the tooth that remains. If your crown feels loose, contact your dentist’s office.

         Crown falls off. Sometimes crowns fall off. Usually this is due to an improper fit or a lack of cement. If this happens, clean the crown and the front of your tooth. You can replace the crown temporarily using dental adhesive or temporary tooth cement that is sold in stores for this purpose. Contact your dentist’s office immediately. He or she will give you specific instructions on how to care for your tooth and crown for the day or so until you can be seen for an evaluation. Your dentist may be able to re-cement your crown in place; if not, a new crown will need to be made. 

         Allergic reaction . Because the metals used to make crowns are usually a mixture of metals, an allergic reaction to the metals or porcelain used in crowns can occur, but this is extremely rare.

         Dark line on crowned tooth next to the gum line. A dark line next to the gum line of your crowned tooth is normal, particularly if you have a porcelain-fused-to-metal crown. This dark line is simply the metal of the crown showing through.

 

What Are “Onlays” and “3/4 Crowns?”

Onlys and 3/4 crowns are variations on the technique of dental crowns. The difference between these crowns and the crowns discussed previously is their coverage of the underlying tooth. The “traditional” crown covers the entire tooth; onlays and 3/4 crowns cover the underlying tooth to a lesser extent.

On average, dental crowns last between 5 and 15 years. The life span of a crown depends on the amount of “wear and tear” the crown is exposed to, how well you follow good oral hygiene practices, and your personal mouth-related habits (you should avoid such habits as grinding or clenching your teeth, chewing ice, biting your fingernails, and using your teeth to open packaging).

While a crowned tooth does not require any special care, remember that simply because a tooth is crowned does not mean the underlying tooth is protected from decay or gum disease. Therefore, continue to follow good oral hygiene practices, including brushing your teeth at least twice a day and flossing once a day-especially around the crown area where the gum meets the tooth.

What are dental crowns?

Dental crowns are restorations that protect damaged, cracked or broken down teeth. A crown strengthens your existing, damaged tooth so as to preserve its functionality. Dental crowns are also commonly known as caps (because a crown sits over your existing tooth, covering the entire outer surface). The animations below graphically illustrate the procedure of placing dental crowns:

 

 

 

 

Crowns should not be the first choice just to improve the aesthetics of your teeth, because a dentist needs to grind a significant portion of the original tooth away. Less invasive alternatives include veneers or dental bonding. Crowns are required when the strength of the tooth supporting the restoration is compromised, since veneers and dental bonding restorations are only as strong as the supporting tooth.

What materials can crowns be made from?

In modern-day dentistry. there is a wide variety of dental materials to choose from. Some crowns are made from full gold, where as others are made from an alloy of metals fused to a porcelain outer shell. After time, crowns that are made from a combination of metal fused to porcelain can begin to show dark gum lines that are not aesthetically attractive. All-porcelain or -ceramic crowns are the best choice for a natural cosmetic look. There are many different brands and types of porcelain crowns, and the variation between the costs of dental crowns at different dental practices may well reflect the quality of the materials used.

What does the procedure of having dental crowns fitted involve?

Once you have had a consultation with your dentist and discussed all the treatment options, he/she will prepare the tooth for crowning. The first stage is to clean the tooth, remove any decay and reshape it using a burr (a special dental drill for shaping teeth) under local anaesthesia. The shape of the prepared tooth is usually tapered to allow the crown sit comfortably over the top of it. Once the tooth is prepared, an impression (mould) of your teeth will be taken using a special “dental putty”. This impression is sent to a dental laboratory, which will use the impression of the prepared tooth as a guide to fabricate the new crown to fit perfectly. It usually takes between two to three weeks for a laboratory technician to custom-fabricate your new crown. During this time, your dentist will fit you with a temporary crown to cover and protect your prepared tooth.

On your second visit, your dentist will remove the temporary crown and roughen the outer surface of your prepared tooth with a special etching acid to give the dental cement a good surface to bond to. Your dentist will sit the crown over your tooth to see if it fits with your smile correctly and is the right colour and shape. Once you are both happy with the restoration and how it looks, your dentist will cement the crown firmly into place.

How long do crowns last?

This will depend largely on how well you look after your teeth. Dental crowns require the same level of care and attention as your natural teeth. Provided you have a good oral hygiene program, attend regular checkups at your dentist, don’t grind your teeth, maintain a tooth-kind diet and don’t do things like open beer bottles with your teeth, a high-quality dental crown can last 10-15 years.

 

 

 

The following case illustrates four crowns.  Cynthia had several large fillings in her upper front teeth.  The central incisor (the middle tooth on the left) had a large bonded composite which had been redone several times over the years.  Notice the dull surface.  She desired a more permanent cosmetic solution.  Prior to the crowns, home bleaching was done.  The final result is very pleasing and natural.

 

Annette had been living with a mismatched crown on her front tooth for many years.  The color is obviously too light.  Furthermore, the porcelain is very opaque giving what dentists call the “chiclet” appearance.  The tooth also had drifted and appeared longer than the other teeth.  Smile solutions discussed included a complete makeover.  However, Annette preferred to address the one tooth.  The result from such a simple approach is astounding.  

A crown is a dental restoration typically made in a dental laboratory that is placed over a natural tooth to replace damaged or unsupported tooth structure. Natural crowns may need to be replaced if they have been damaged by tooth decay, chipping or breaking. Artificial crowns can also be used as part of a bridge or as a restoration over an implant. They are commonly used after root canal treatment because the procedure can make the tooth brittle. A crown will protect the tooth structure from fracture.

Crown restorations range from full crowns that cover the entire natural crown of the tooth (the top surface of the tooth) to three-quarter crowns that leave the front of the tooth exposed (commonly used on front teeth). Crowns may be made of metal alloys (e.g., gold, copper, nickel, chromium), porcelain, porcelain fused to metal, or a type of plastic called composite resin.

The restoration process for a crown is a multistep process, beginning with a dental examination and x-rays. In many cases, root canal treatment is the first step. A diseased or decayed tooth has its pulp removed from its root canal and replaced with material called gutta percha.

  After the initial examination and any preliminary dental work, crowns typically require two or more visits: one to prepare the tooth and take impressions and another to cement the permanent crown to the tooth. Between these visits, the patient wears a temporary crown. There is usually little or no discomfort after a crown has been placed, although some patients may experience some sensitivity to hot and cold. If any additional problems arise, patients should speak with their dentist.

Crowns can closely match the color, shade, shape and length of neighboring teeth and are often difficult to detect as artificial. However, various problems (e.g., chipping, fracture, breaking, loosening, falling out) may require that crowns be replaced. In some of these cases, the crown may be able to be repaired in the mouth or re-cemented, depending on the amount of damage that has occurred.

In general, crowns require the same care as natural teeth. However, it is typically recommended that patients with crowns avoid chewing on extremely hard substances (e.g., nuts, ice), grinding their teeth and biting their fingernails. These activities can damage the crowns or reduce how long they last. Crowns do not protect the teeth from tooth decay, periodontal disease and other common oral concerns. Therefore, diligent dental hygiene remains extremely important

A crown is an artificial cap made to cover a natural tooth. The term “crown” can refer to a natural crown (the part of a tooth that is visible in the mouth) or a dental restoration that covers the top part of the tooth. 

An artificial crown is a dental prosthesis that covers or replaces the natural crown of a tooth. It typically covers the entire natural crown, on all sides and chewing surfaces. Artificial crowns can be used to cover and strengthen teeth that have been damaged. They may be used to improve the appearance of a tooth that is oddly shaped, badly discolored, or not in proportion with the neighboring teeth. Crowns can be used in cavity restoration when the tooth decay is too widespread for a filling, to restore a broken or cracked tooth, or prevent a tooth from breaking.

Crowns are commonly used as the last step after root canal treatment. Teeth become brittle as a result of this treatment and a crown will prevent further damage to the tooth (e.g., fracture). In these cases, the pulp of the tooth is removed from the root canal and the canal is filled with material such as gutta percha. A post may be placed in the root canal if there is insufficient natural tooth to support a crown. A crown is then typically placed in the area. Crowns can also be used to support a bridge or cover an implant.

Other types of dental restorations include inlays and onlays. These restorations cover smaller portions of the tooth, such as only the top part of the chewing surface. Inlays cover the smallest portion and may be slightly larger than a filling, while onlays cover at least one cusp of a tooth. Because onlays cover the cusps of teeth they offer better structural support. Inlays and onlays are more conservative restorations than crowns because less tooth structure is drilled away to fit.

Multiple visits to a dental office are required to prepare, place and adjust a crown. The crown is constructed in a dental laboratory based on impressions taken by the dentist. The multiple visits and labor crowns require means they usually cost more than simpler restorations, such as fillings.

Crowns require the same dental hygiene (regular brushing and flossing) as natural teeth. Crowns can last many years, depending on the location in the mouth and the level of dental hygiene.

Types and differences of crowns

The term “crown” can refer to either the natural crown which is part of a tooth or an artificial crown which is a dental restoration.

The natural crown of a tooth may be defined in two ways:

Anatomical crown. The part of the tooth covered by enamel, which may be above or below the gumline.

Clinical crown. The portion of the tooth visible inside the mouth and not covered by soft or hard tissue.

Different types of artificial crowns include:

Full crown. An artificial crown that covers the entire natural crown.

Jacket crown. A thin crown that covers large areas of the natural crown in the front teeth. It may not be strong enough for use in the back teeth, which endure greater levels of chewing stress and pressure.

Dowel crown. A full crown that is anchored by a dowel pin that extends into the root canal of a tooth that has undergone a root canal treatment.

Three-quarter crown. A crown that covers all of a natural crown except the front surface of the tooth, which remains natural for aesthetic purposes.

Abutment crown. An artificial crown used to support a bridge or cover an implant.

Artificial crowns may also be classified by their materials:

Gold alloys. Composed of a combination of gold, copper and other metals. These materials are strong and highly resistant to tarnishing, corrosion, fracture and wear. These materials do not tend to require as much removal of the underlying natural tooth material as other crown materials. They are compatible with the nearby teeth and are well tolerated by patients. However, many patients find the metallic gold color displeasing for teeth that are visible when talking, smiling or laughing.

Base metal alloys. Composed of a combination of base metals (e.g., nickel, chromium). These materials have strength and resistance qualities similar to gold alloys. However, they have a metallic silver color that many patients do not like. They may also cause an allergic sensitivity or initial discomfort with hot and cold in some patients.

Porcelain. May be composed of porcelain, ceramics or glasslike materials. These materials have a color and translucency that closely matches natural teeth. They are also highly resistant to wear. However, they may be prone to fracture and can wear dowearby teeth if the porcelain surface becomes rough. They may also require the removal of a larger amount of natural tooth than metal alloy crowns to support enough porcelain to produce a strong crown.

Porcelain fused to metal (PFM). Composed of a porcelain crown bonded to a metal base. This combination is strong and durable and highly resistant to wear. However, it can wear dowearby teeth if the porcelain surface becomes rough. It may also cause an allergic sensitivity or initial discomfort with hot and cold in some patients. In addition, it may require the removal of a larger amount of natural tooth than metal alloy crowns to support the combined metal and porcelain.

Composite resin. Composed of a type of composite plastic similar to the material used in tooth-colored fillings. This material tends to be relatively inexpensive and looks like natural teeth. However, it may stain more readily than porcelain and is not as strong or durable as porcelain.

Before the crown procedure

Before a crown can be placed, patients need to see a dentist for a dental examination to determine what type of crown is right for them. The dentist may also evaluate the patient’s medical and dental history. In some cases, a root canal treatment may be necessary due to extensive tooth decay. This treatment may also be needed if the tooth has to be reduced to such an extent that the tooth’s pulp may be injured or risk infection.

If there is not enough natural tooth structure to support the crown, a foundation may need to be built up, frequently around a pin or a post. Pins are thin shafts, typically made of metal, that are inserted into a hole that has been drilled into the tooth. They are becoming less common due to advances in adhesive dental materials that now allow weaker or smaller teeth to support crowns. Posts are thicker rods, frequently made of metal, that are inserted into the root canal of a tooth that has undergone root canal treatment.

After the initial examination and any preliminary dental work, crowns typically require two or more visits: one to prepare the tooth and make impressions and another to cement the crown to the tooth. The tooth that will support a crown must first be prepared by reducing its size to make room for the crown. Surrounding teeth may also require some adjustments so the crown will fit.

During and after the crown procedure

After the tooth is prepared, the dentist takes an impression of the prepared tooth and nearby teeth. A medicated thread or cord may be used to separate the gum from the tooth, allowing a more accurate impression. The impression will be sent to the dental laboratory, where it will be used to make the crown. The dentist then places a temporary crown, which the patient will wear until the permanent crown is placed. Temporary crowns may be prefabricated or made from resin in the dental office. They do not last long, but keep the prepared tooth safe until the permanent crown is available.

Crowns are generally made in dental laboratories and may take several weeks. After the crown arrives, the dentist removes the temporary crown and checks the fit of the permanent crown. The dentist makes any necessary adjustments (e.g., polishing, glaze) and temporarily cements the crown onto the prepared tooth. The dentist also ensures that the patient’s bite is correct with the new crown. If the crown is comfortable and satisfactory to the patient, the crown will be permanently cemented. This may occur at a later date.

There is usually little or no discomfort after a crown has been placed, although some patients may experience some sensitivity to hot and cold. In some crowns (e.g., porcelain fused to metal crowns), a dark line may be visible along the gumline. This is a small, visible portion of the metal base of the crown. It is not noticeable in most cases.

If any additional problems arise, such as pain or sensitivity when biting down, patients are advised to speak with their dentist. Some issues can be fixed in the dental office in a single visit. Others may require replacement of the crown.

The multistep process of preparing a tooth for a crown and having the crown placed may take weeks. Researchers are investigating new techniques that may help to reduce this time, allowing dentists to place crowns much sooner after the tooth has been prepared.

Potential risks and benefits of crowns

Crowns have a natural look and feel that many patients consider superior to bridges and other forms of dental restoration. They can closely match the color, shade, shape and length of neighboring teeth and are often difficult to detect as artificial. They are generally considered affordable and are usually covered by insurance.

Crowns also have drawbacks. Many problems may require the crowns be replaced. Crowns may chip, fracture or break. Sometimes, chips or fractures can be repaired with composite resin without removing the crown. However, in many cases, the crown must be removed and a new crown placed.

In some cases, the porcelain part of a porcelain fused to metal crown may detach from the metal. It may come apart cleanly, or parts of the porcelain may remain attached to the metal. In some cases, these crowns can be bonded back together. However, they often must be replaced.

Tooth decay can still occur in the underlying tooth. Poor placement of the crown may allow food to get under the crown, or the cement may partially wear or wash out, making the crown loose and unstable. Patients should continue daily dental hygiene (brushing and flossing) and monitor any unusual changes around the crown. To avoid tooth decay, it is important to see a dentist as quickly as possible when a crown becomes loose. The crown can often be re-cemented before any damage to the tooth itself occurs. If the tooth does become damaged, the crown will no longer fit properly and a new crown will need to be made.

Occasionally, a crown may become loose and fall out entirely.  It is important to see a dentist as soon as possible to ensure that the crown and tooth are not damaged. If either becomes damaged, the crown will no longer fit properly and a new crown will need to be made.

Finally, changes in the material of a crown (e.g., discoloration, wear) or changes in the surrounding teeth (e.g., whitening attempts) may cause a crown to become unattractive. Patients may wish to have such crowns replaced.

Lifestyle considerations with crowns

In general, crowns require the same care as natural teeth. However, it is typically recommended that patients with crowns avoid chewing on extremely hard substances (e.g., nuts, ice), grinding their teeth and biting their fingernails. These activities can damage the crowns and reduce durability.

Crowns can last many years. According to the Academy of General Dentistry, crowns tend to last for around five to eight years. However, diligently cared for crowns can last many decades.

It is important for all patients, whether or not they have artificial crowns, to see a dentist regularly for a dental examination and cleaning. Diligent dental hygiene is also extremely important. Crowns do not protect the teeth from tooth decay, periodontal disease and other common oral concerns. While patients with crowns are not generally required to do anything that is not recommended for natural teeth as well, they may be advised to pay particular attention to the area of the tooth by the gumline. This is where plaque and decay may get under the crown and damage the underlying natural tooth.

About Dental crowns

A dental crown is a tooth shaped restoration that covers the tooth thus improving the size, shape, strength, and appearance of the tooth. A crown is a cap that completely encases the visible tooth surface including the gum line when cemented over the tooth structure. In general, crown is an artificial, synthetic tooth that is designed from wide range of materials in order to improve an esthetic appearance as that of a natural tooth.

An artificial crown is a fixed prosthetic restoration that covers more than half of the coronal portions of the tooth. There are several types of crowns. They may be made of gold, porcelain, acrylic, or a combination of these materials. Along with onlays, which are classified as extracoronal restorations, are the various kinds of crowns that make up the balance of the extracoronal category. Partial Crown A partial crown is a cast restoration made entirely from metal and covers more than half but not all of the tooth’s clinical crown. A partial crown is named according to the fractional amount of the clinical crown it covers. Examples are the half, three-quarters , four-fifths, and seven-eighths crowns . In most instances, the facial surface of the tooth is not disturbed for esthetic reasons. Complete Crown A complete crown covers the entire anatomy of a tooth’s clinical crown. There are several types of complete crowns. A complete metal crown is constructed entirely of a noncorrosive metal, such as gold . A complete veneered crown consists of complete coronal coverage of the tooth with a metal substructure overlaid with porcelain or resin for esthetic effect. A complete crown constructed of cast metal with a fused porcelain (ceramic) veneer is commonly called a PFM (porcelain-fused-to-metal) crown. A post crown is a complete crown of any kind (complete metal, veneer), supported by a metal extension (post) into a tooth’s root canal. Because the pulp is removed from teeth that are endodontically treated, the teeth eventually become brittle and are prone to fracture. In many instances, the teeth are also destroyed by caries or previous restorations and very little clinical crown is left. Often, only the root portion is left to retain the crown. To maintain an endodontically treated tooth as an abutment (anchor) capable of supporting and retaining a crown, it is common practice to cement a post about two-thirds of the way into a root canal. To do this, a gold casting

Crowns are usually designed from ceramic, porcelain or metals like gold and also various material combinations which are basically fused between porcelain casing and various metals. Permanent crowns are usually made of porcelain-fused-to-metal (PFM), metal, resin, or a complete ceramic. In general, crowns can vary based on the used type of material.

Some of the different types of crowns include All-porcelain or All-ceramic crowns- which caaturally match with the tooth color, indicated for front teeth and metal allergic patients; Porcelain-fused-to-metal (PFM) crowns- which can match best with the adjacent teeth thus providing a natural look, indicated for both front and back teeth; Metal crowns that are made of palladium alloy, gold alloy, or a base-metal alloy like chromium or nickel- which can last longer but not esthetic, indicated for out-of-sight molars; All-resin crowns- are cost effective and prone to fractures; temporary crowns made of stainless steel or acrylic- are designed in dental practice; and permanent crowns- are designed by dental laboratory.

When is a dental crown needed?

There are a number of conditions when crowning may be required. Some of them are:

    To protect any tooth from breakage or decay and in some cases to hold pieces of a cracked tooth together.

    To restore a broken tooth.

    To support and cover a tooth with an outsized filling in case a large part of the tooth is not available.

    To keep a dental bridge in its place.

    To cover up a tooth that is highly discolored.

    To cover up a dental implant.

Some typical use cases of dental crowns:

    In case of a cracked tooth resulting from chewing with excessive force, crowning becomes essential.

    A tooth which underwent root canal treatment may become weak and be more vulnerable to a fracture. Thus, it needs to be covered by a crown so that chances of fracture are minimized.

    When a tooth becomes fractured such that any filling cannot restore it then it has to be replaced with a crown.

    Amelogenesis Imperfecta is a hereditary condition where the enamel of the tooth becomes very brittle, gets fractured easily, and thus requires crowning.

    Dentinogenesis Imperfecta is another condition where the dentin becomes defective. This results in wearing of the dentin pulp and the enamel and thus needs to be restored by crowns.

Dental Crown Procedure

Initially, the dentist will take some X-rays of the tooth that is going to receive the treatment. In case the damage is too much, then, first a root canal treatment has to be given. Crowning is not a simple process but modern technology and techniques have made it simple and pain free.

The process begins by anesthetizing the gum-tissues surrounding the tooth. Then the concerned tooth is filed along the sides and the surfaces in order to get crown some space. The amount of the tooth to be filed is a prime factor in deciding the usage of crown-type. If a large part is missing then some filling material comes in handy to create support for the crown.

Once the reshaping is over, some putty is used to take the impression and mark of the concerned tooth so that the crown can be made perfectly well.

During the first visit to the dentist, you will be provided a crown for temporary use so that the filed tooth is safe.

The second visit to the dentist is all about getting the permanent crown. The temporary crown is removed and the permanent one is checked for color and fitting. If it is perfect then the crown is cemented permanently.

This is how the process of crowning looks like. Some problems may develop after the crown is cemented like allergic reactions, discomfort, sensitivity, chipping off, loosening, falling off, cracking etc. Generally, a crowned tooth does not require any special care regimen but it also does not ensure complete protection to the underlying tooth from gum disease and infections. Thus, brushing and flossing must be done regularly.

Various types of crowns

    The metal crowns comprise of gold alloy, other alloys and base metal alloys. They are strong crowns and last longer as compared to other types. The major drawback is their distinct color.

    PFM or porcelain fused to metal crowns can be matched to the color of the neighboring teeth. They are subject to more wear and tear but look like natural tooth.

    All resin crowns are very economical but are vulnerable to damage and fractures.

    All porcelain or all ceramic crowns are the best to get the natural looking tooth but are comparatively less strong. They are a good option for front tooth.

    Gold crowns are made of gold but are rarely preferred because of reduced aesthetic appeal.

    Zirconia crowns are the most durable and natural looking type of teeth crowns. Their only disadvantage is their higher price.

All resin crowns

All resin crowns are comparatively less expensive but they undergo wear and tear with time and are vulnerable to fractures.

They are constructed from composite material which is similar to the one used for normal color fillings in the mouth. They are the most natural looking crowns as compared to others.

These are best suitable for restoring front teeth. They also do not wear down the tooth opposing them.

Long back in 1839, the first resin that was used for tooth restoration was vulcanized rubber. After that, technology has progressed and many other types of resins have been discovered which can easily be used for dental applications.

Presently in dentistry, acrylic polymer resins are most commonly used in crowns and dentures. Another common variety that is used is Polymethyl Methacrylate. This particular variety of resin is prepared by blending chemical units known as monomers along with activating chemicals. This enables the monomers to link together and react in order to form long chain polymers. With the reaction in progress, these resins may harden at room temperature. Other types may need ultraviolet light or heat to catalyze the required change.

Composite resins

These crowns are the ideal option for a perfect smile. It is a silicon dioxide mixture filled with tooth colored plastic matter, which is very helpful in restoring the health and look of a tooth.

Since these crowns are not made of metals they can easily be mixed in to a number of shades to match the shade of an individual’s natural teeth.

It also protects the remaining part of the tooth from breakage and temperature changes.

The resin crowns are aesthetically very appealing as they represent the natural look and color of a tooth. In addition, they are metal free. A major disadvantage is that a large part of the tooth structure is removed for placing this crown. Gingival inflammation is more common with this type of crown.

Procedure for fitting a resin crown

It generally is a matter of two visits to the dentist for placing a resin crown. This is so because it takes time as the crown which suits your tooth perfectly has to be hand crafted or custom made in the laboratory which requires skill and expertise.

Initially the tooth under treatment is numbed with local and topical anesthetic. After that, any kind of decay on the tooth is removed. Next, the tooth is reshaped with the help of a hand piece. Then a precise impression of the tooth is taken and a temporary crown is fitted on the tooth.

In the meantime, the permanent crown is manufactured in the laboratory. When the final resin crown is ready, again, the tooth is numbed and the new crown is fitted on it.

Personal care has to be taken when the temporary crown is placed on the tooth. The success of the treatment and the health of the gums all depend on this care.

Full Porcelain Crowns

Today all ceramic or full porcelain crowns are considered the most beautiful crown that a tooth can get.

Porcelain is a kind of ceramic built by firing and stacking and ceramic refers to porcelain only.

Pure porcelain is the only crown which gives the desired translucent look to the tooth. The major drawback in using all porcelain crowns for restoring the front tooth is that the expertise required to place them is very challenging but still are placed there for their aesthetic appeal.

They are translucent in color and generally, their color is influenced by the tooth under them.

Types of all ceramic/full porcelain crowns

There are various types of these crowns and they are mentioned here.

    Feldspathic porcelain is the most traditional type that is used and is most beautiful.

    Empress crown looks like that of a glass and can be called ceramic.

    Procera crown has milled ceramic inside and traditional porcelain on outside. This crown is used because of its extraordinary strength. It can be cemented with the help of an ordinary bridge cement and crown.

    Lava crown has a translucent Zirconia on the inside which is shaded and finally looks beautiful on the outside due to its baked layer.

    Zirconia crowns look natural and do not reveal a black line like other crowns at the gum line.

These crowns are best suitable for people who are allergic to metals.

Our natural tooth is translucent in color and these crowns are the only ones with such translucency. A major problem with these crowns is that they are not as strong as PFM crowns.

Advantages of these crowns

    Transparent and true to nature and aesthetically appealing

    No allergic reactions and highly biocompatible and reduced sensitivity

    Alignment and form correction is possible

    Ideally suitable for patients who have reduced space inside their mouth and are looking for that natural looking tooth

Disadvantages

    Preparation time is very high and complicated

    Comparatively expensive

    Less durable than other types and vulnerable to breaking and cracking

The procedure for the fitting of these crowns is similar to that of any other crown:

The tooth to be treated is cleaned, reshaped, and thus prepared for treatment. The tooth is also a little tapered so that the crown can snugly fit on top of the concerned tooth.

With the help of dental putty, an impression of the tooth is taken.

The mould is then sent to the laboratory for fabrication of the new crown. In the meantime, the patient gets a temporary crown fitted on the tooth. A period of two to three weeks is required for the crown to be prepared.

Then the patients tooth is fitted with the new crown. For this, the dentist roughs up the surface of the affected tooth with the help of etching acid which enables the crown to hold on to the tooth.

After the desired fitting is obtained, the crown is firmly fixed with the help of dental cement. Care must be taken to avoid grinding, biting into hard foodstuffs and clenching.

Gold Crowns

Gold crowns are not a very popular choice among patients as it does not have much aesthetic appeal. They are suitable for patients who are in the habit of biting strong food substances along with clenching and grinding.

Gold crowns offer increased durability and are suitable for the back teeth like the molars so that they are not visible.

Forms of Gold crowns

Gold crowns are available in three forms:

    Full gold crowns- they are made to cover up the whole tooth up to the gum line.

    Gold inlays- these are gold castings used to replace particularly those areas where a distinctive filling has to be placed.

    Gold onlays- they are equally strong as full crown but have reduced tooth width reduction and the edges do not touch the gum line.

Reasons for preferring Gold crowns to other crowns

    When a tooth is restored with gold crown, there is very less tooth width reduction and a good portion of the tooth and enamel is left untouched.

    Restoration with gold crown does not result ierve problems and bleeding of the gums as compared to other crowns.

    Gold crowns are very durable and are less abrasive than the other types.

    Gold castings fit more accurately and perfectly on the prepared tooth but the porcelain ones shrink when applied.

    Gold restorations serve for a long period and are sometimes preferred for their longevity.

A gold crown is generally costly as the price of gold is very high but is not a problem for affluent patients.

Gold crowns are a comfortable and safe option to choose as it is very compatible with the interiors of the mouth. The chances of allergic reactions are minimal in this case.

Gold restorations last for up to 20 to 40 years.

Another important advantage of using gold for crowning is that the rate at which gold contracts and expands is similar to that of natural tooth. This prevents the gold from cracking, chipping and breaking away from the tooth. Also, the smoothness and purity of gold is commendable and does not stain or darken over time.

The fitting that a gold crown provides is better as compared to the porcelain ones and this is also the reason for its long life. Gold crowns do not undergo fractures like the porcelain crowns. A major disadvantage of porcelain crowns is that they scrape the opposite teeth faster than a natural tooth but gold does not do so. Again, gold is a metal which is very smooth as compared to other metals. Porcelain crowns are rough and bacteria added food particles can easily stick to it increasing the chances of infections but gold can be cleaned easily.

Tissues surrounding a gold crown stay healthier as compared to porcelain as irritation and sensitivity is minimized. This becomes beneficial as one ages.

Differences between PFM versus all e-max and zirconia crowns

Metal crowns

Metal crowns generally make use of gold alloys or base metal alloys like that of chromium or nickel.

If compared to the other crown types with metal, minimal amount of tooth structure has to be removed and wearing out of adjacent teeth is also minimal.

Since these crowns are made of metals, they can withstand chewing and biting forces well and last for over a very long period. They hardly break or chip off.

The key drawback of metal crowns is their metallic color. They are best suited for restoring hidden molars.

Advantages of metal crowns

    The most significant advantage of metal crowns is their tremendous strength.

    Crowns made completely of gold are of very good quality.

    Metal crowns cause minimal wearing of the surrounding teeth as compared to others.

    Metal crowns require very little amount of filling for the tooth.

    Metal crowns last for a very long period and resist chipping and breaking better than other types of crown.

    They are very durable and are used for the restoration of hidden teeth.

    These are best suitable for patients who have strong chewing habits and are likely to clench and grind their teeth often. Thus, metal crowns are suited for the back teeth.

Disadvantages

    The only main disadvantage of metal crowns is their metallic appearance.

Metal crowns are sometimes prepared with porcelain fused to them and are referred to as porcelain fused to metal crowns (PFM). They have a strong metal core in the inside and then a layer of porcelain is cemented on it. The final look is that of a natural tooth.

Advantages of PFM crowns:

    In case of purely metal crowns, the metallic shine is a drawback but here the shade exactly matches the shade of the patients tooth.

    These crowns can be easily used on tooth which is visible unlike the all-metal crowns.

    The quality of these crowns is very durable and superior as they have a metal in their core shell.

    They have enough strength, are highly durable, and can easily bear strong chewing forces.

Disadvantages

    These porcelain crowns can cause wear and tear of the surrounding teeth causing pain and infections.

    There are more crowns that are vulnerable to breaking and chipping as compared to all metals.

    Since the porcelain covering is translucent, it sometimes makes the underlying metal visible which can be embarrassing for the patient.

    In case the gums recede, problems at the gum line of the crown may result.

Metal crowns are fixed in the same way as other crowns. It requires two successive visits to the dentist to get them permanently fixed.

On the first visit, a number of X-rays of the concerned tooth are done and then it is numbed.

All decay is cleared and then an impression of the teeth is taken.

While the permanent crown is prepared, a temporary crown is placed on the tooth to protect it.

After the permanent crown has arrived, it is cemented to the tooth permanently.

Porcelain fused to metal crowns

Porcelain fused to metal crowns (or PFM crowns) can be referred to as full-cast crowns which has porcelain fused on most or all parts of the tooth. Metal alloys with a high melting temperature are used to fuse porcelain to the surface and preventing the metal from melting. This ensures the porcelain to bond without changing its color.

When the tooth is prepared for such crowns, a large part of the tooth tissue gets removed making space for porcelain as well as the metal.

Porcelain crowns are the most preferred crowns as they easily match the color of the adjacent teeth better than the metallic crowns. However, they cause more damage to the opposite teeth than the resin and metal crowns. Some cases show that the porcelain portion of the crown can also break or chip off from the teeth.

In receding gums, such crowns are not suitable as the porcelain can start showing distinctively. They are best suited for the back and front teeth.

Advantages of porcelain fused to metal crowns

    The underlying metal fused with the porcelain provides stability and strength to the crown.

    It has great aesthetic appeal and is most commonly preferred as it gives the restored tooth a natural look.

    They have a very high rate of success in the long run.

Disadvantages

    The cosmetic appearance of these crowns is commendable but they are less appealing than other types.

    They make the gums more vulnerable to gingival inflammation as compared to porcelain fused to gold and porcelain crowns.

    Restoring tooth with these crowns requires a large part of the tooth structure to be removed.

    Porcelain from the crown can easily break or chip off.

    The teeth which bite against these crowns bet worn out in the long run.

    Increased cost becomes a major drawback when precious metals are fused.

PFM crowns are nothing but a hybrid between porcelain and metal crowns. Initially a metal shell is prepared which can fit perfectly over the concerned tooth. Then a porcelain veneer is fused on the metal shell which gives the crown a natural looking appearance.

The best part of these crowns is the stability and strength which is unmatched to any other restorations available today.

These are best for patients looking for natural look and durability.

Last few years have seen a lot of advancement in the field of porcelain fused to metal crowns. Patients with all porcelain crowns are getting theirs replaced with these ones. The latest type of Captek crowns have also done away with the black line that becomes visible around the patients gum line. These crowns have been the commonest option for dentists as well as for patients for over 35 years.

PFM is a preferred choice when bridges for the long run are required and night grinding is a problem. Since these crowns are a combination of porcelain and metal they are accepted worldwide and well known for the treatment they cater. They are trusted not only by the patients but also by the doctors all over the globe.

Porcelain fused to metal dental crown (PFM)

Porcelain fused to metal crown (PFM) is a full cast crown that is constructed by fusing the porcelain to all or most of the metal surfaces.

Indications of porcelain fused to metal crown

A PFM dental crown is indicated in case of minimal inter-occlusal clearance that requires a stronger restoration. It is also used on any tooth that requires a full crown for preventive and restorative purposes.

Contraindications of PFM dental crown

PFM dental crown is contraindicated when the size of the tooth pulp is negligibly smaller thus compromising the tooth preparation process. It is also contraindicated when the clinical tooth crown is very short and lacks the required stability including retention that is enough to provide the space for porcelain and metal.

Advantages of PFM dental crown

The major advantage of PFM crown is its metal substructure that provides adequate strength.

Disadvantages of PFM crown

PFM crown requires removal of 1.5 mm of buccal tooth substance to place the porcelain and metal layers. It lacks esthetic look due to its opaque metal layer. An e-max or a zirconium crown can be a best option when one is looking for an aesthetic appearing tooth crown.

Procera crowns

Procera crowns are ceramic crowns that are totally metal free. The fabrication of Procera crowns is required to be completed by an experienced and accomplished dental surgeon characteristically in dental laboratories, which is definitely outside the premises of dental practitioner’s office.

The procedure of Procera crowns involves the dental technician constructing a thin hard-edged ceramic so that it can be used in the form of base material as the application in porcelain.

The specialist is then required to apply the porcelain to the created thin hard-edged ceramic under construction. He is required to provide shape and color as required in the different cases of individual patients.

Soon after the application of porcelain is completed, the Procera dental crown is taken to a porcelain surface only to be baked so that it can be delivered as per the need of the dentist.

The dentist checks whether the Procera crown is as per his requirement and makes sure, if it is properly fitted in his patient’s mouth. He checks to see if any further adjustments are necessary to be made.

If everything goes according to his will, he cements the Procera crown everlastingly. Even though it sounds a bit cumbersome, once the process is done, it gives a sigh of relief to the patient.

The Procera crown provides your gums and teeth with the natural beauty that was not possible before.

The practitioners usually do not face problems or issues in preparing them. Besides the easy preparation, it also aids in the easy cementation process because of the quality of the crowns.

This gum-friendly ceramic crown re-forms the forte and the natural beauty as mentioned earlier.

More than one hundred thousand patients with Procera crowns have already been cured.

The visual quality is also overwhelming because of its optimally fittings and naturally genuine ceramic features.

The last couple of years have seeew technology with improved properties making way. Thus, patients ask for structures that do not consist of any metals or alloys. This is because; Procera crowns are made of a biocompatible substance which prevents the risk of an allergic reaction.

Since Procera crowns displays unmatched power in their materials, they are usually recommended by dentists for easy renovations anywhere in patient’s mouth.

Temporary Dental Crowns

A temporary dental crown is an interim, short-term reinstatement taken place in dentistry.

Generally, the temporary dental crown is fashioned via chemical-cure combination, though other systems of constructing dental crowns of aluminum are sporadically used by doctors.

The provisional substance is designed by the dentists to produce a tooth structure which aims to protect the arranged tooth and targets prevention of injury to gums and masks the equipped tooth to a certain point until the concluding restoration is done by the practitioner.

A temporary crown is typically concreted in the desired place with easy-going provisional dental cement, for example Temp-Bond NE. This permits relaxed elimination when appropriate restoration is taking place.

How is the Temporary Crown prepared?

A temporary dental crown is prepared by the dental assistant and hygienist. The steps that are necessary in preparing the temporary dental crown are:

    Firstly, it is of utmost importance that an imprint of the readied tooth and contrasting teeth is finished.

    Using this imprint, a sticking plaster mould is made ready.

    The temporary dental crown is characteristically constructed out of the chemical-cure composition from the sticky plaster mould. Some older practitioners carry out the previously constructed aluminum dental temporary crowns.

    After the crown has been prepared, it is paved onto the set tooth with lenient, effortlessly detachable cement.

    The patient is then asked to nibble on the temporary crown to make the cement hold in its place.

    Surplus cement is detached by the support staff.

    The tooth after being crowned prevents the air from getting into the unprotected bare nerves and thus causing no pains to the bare nerves.

    The times when the patient’s temporary dental crown is on, the doctors advise them to stop flossing their tongues on the zone around the fresh temporary crown. They are further asked to brush as gently as possible and to avoid chewing gums and foods that are hard and sticky iature.

What to do when your temporary dental crown wears off?

It is common for temporary crowns to get dislocated even before the predicted lifespan. If such a thing happens when the dentist is unavailable, the patient can himself set it back in place by smearing Vaseline or the toothpaste on the insides of the provisional crown and setting it back on that tooth. Biting down the crown is the next step. Once the dentist is available, rush to him as quickly as possible. He will help you in the temporary re-setting of the teeth.

Veneers

Veneer is a form of dental cosmetic product that protects the surface of discolored or damaged teeth.

Dental veneers are indirectly fabricated in a dental laboratory by a dental technician and are later bonded to the damaged tooth.

There is no reason why anyone should put up with gaps in their teeth or with teeth that are discolored, badly shaped or crooked. In today’s dentistry, a veneer can be placed over the teeth to correct nature’s mistake or the results of an injury and help you have a beautiful and sparkling smile.

Veneers are thin, custom-built shells designed to coat the front side of teeth. There are two types of veneers; the composite and the dental porcelain.

Types of Veneers

Composite Veneers

Composite veneers cover the facial surface of the tooth to correct the color, position or shape of the tooth.

When composite is added, the tooth structure increases in size and that is why tooth reduction is usually done to make room for the composite placement. The amount of reduction is determined by the position of original tooth in relation to the aspired position and color of the tooth’s structure in relation to the thickness of the composite materials required to block out color.

Composite veneers can be directly made on your teeth by your dentist during your dental appointment; these are also known as composite bonding. And this is the inexpensive yet effective way to correct small gaps, crack, and chips, and to treat discoloration of teeth.

Porcelain veneers

Dental porcelain veneers are the most common solution for some dental problems like; discoloration, cracks, chips and worn enamel. Porcelain veneers are thin layers of porcelain or composite materials that are placed on the surface of the teeth. These types of veneers can only be created indirectly at a dental laboratory.

Dental porcelain veneers are more suitable solutions for severe cases like; dullness, wear, discoloration, extensive chipping, cracking, uneven or spacing between teeth.

E-Max Crown

The E-Max dental crown is considered to be a best inclusion in dental crown technology. It is a form of all-ceramic crown which provides best aesthetic appearance by complimenting with the natural teeth and it lasts longer. It has an appealing translucent color and is highly durable with extra strength.

Emax crown is generally constructed by 4 techniques: Pressed, milled Yttrium Zirconia, pressed to Zirconia, and a milled esthetic glass.

Indications of E-Max crown

E-max crown is indicated for stained or damaged teeth with poor quality and to provide an aesthetic look.The E-max crown consists of a block of top grade material, lithium di-silicate ceramic which assures correct fitting, durability, toughness, and opaqueness thus it is priced more. The crown is also made of a glass ceramic crown that is endurable with a higher toughness but still providing a delicate look.

Advantages of E-max crown

The E-max crown has a lifelike shape and transparent color that provides an exact color match with the patient’s owatural teeth. It has no metal alloy base thus does not affect the aesthetics around the gum line. The crown is long lasting, strong, and less prone to fractures when compared to other traditional crown types. When compared to zirconia crowns, an E-Max crown is less likely to get chipped.

Disadvantages of E-max crown

The only disadvantage of E-max crown is its high cost especially during tooth preparation. It requires a premium crown placement without tooth preparation and hence it is more expensive when compared to its other crown counterparts. In addition, e-max crown is not suitable for all patients and one should discuss it with dentist about availability and whether it is the appropriate one.

Zirconia crown

A zirconia crown is made of a strong, biocompatible material, zirconia which is also used in medical applications like artificial joints. It is a well-known, type of all-ceramic crown which significantly improves the tooth appearance that has been previously disfigured or stained for years.

Different types of zirconium dental crowns include:

    glass-infiltrated zirconium toughened alumina (InCeram Zirconia)

    yttrium cation-doped tetragonal zirconia polycrystals (Cercon Zirconia)

    partially stabilized zirconium (Mg-PSZ)

    shrinkage free ZrSiO4 ceramic

    Cercon Base ZrO2 sintered crown

 

Advantages of zirconia crown

Zirconia is a crystal form that is indestructible and lasts longer. It has adequate strength and durability. In fact, its crown cannot be spotted amongst natural teeth. Patients are least likely to develop an allergic reaction to zirconia and thus considered a safe option when compared to porcelain fused to metal crowns.

Zirconia crown is long lasting, easy to wear and durable when compared to other crowns. The translucent appearance of zirconia crowns blends well with the natural teeth color and thus provides the most pleasing appearance. It requires minimal tooth preparation thus preserves most of the original tooth substance which is also favorable while removing the crown. Hence, zirconia crown is an ideal option to cover-up the damage including stains and to restore the tooth function.

Disadvantages of zirconia crown

The zirconia crown is tough, durable and possesses abrasive quality thus imposing the friction against the tooth root including neighboring teeth. Hence, an E-max crown could be a favorable option for cases that require preservation of the root structure.