Dental emergencies. The volume of orthopedic care to maxillofacial wounded

1. Heart failure.Increased secretion of adrenaline as a result of stress reactionboth use of adrenaline as part of anesthesia medicines may lead to to acute cardiac decompensation. For patientsthattakecardiac glycosides, adrenaline can trigger cardiac arrhythmias. Incaseofdisturbedcirculation, development of necrotic processes in the mouth ispossible evenwhentraumatism andquantityofstomatologicalinterventionwasslight.Prevention: perform outpatient dental intervention withpatientfeelingsatisfactory, in other cases provide assistance only in a hospital. With clearly marked heart failure with the threat of decompensation (shortness of breath at rest) the possibility of dental treatment is to be decided with a the patient’s doctor therapist. Be careful when choosing a medication for pain relief (use local anesthetic without epinephrine or with a minimum of its contents).

2. Coronary heart disease.Fear or pain during dental intervention or use of adrenaline in solutions of local anesthetic, may provoke an attack of angina and the development of myocardial infarction.Prevention:If the patient’s condition is unstable (precordial pain orpain behind the breastbone is calm), dental treatment is to be decided with a the patient’s doctor therapist.. if necessary, give the patient a usually dose of nitrate. It is reasonable to do drug training with sedatives before treatment. When doing local anesthesia use themedications, thatdon’tcontainadrenalineor use vasopressinand felipressin asavasoconstrictor in local anesthetics. Injecttheanestheticnomorethan1 carpule(1,8 ml). control the level of blood pressure duringtreatment.After patient’s acute myocardial infarction during the first six months because of the risk of relapse to held only urgent dental intervention in the hospital with anesthesiologist and cardiologist.

3. Cardiac arrhythmia (disturbance of frequency and rhythm of heartbeats). in case of tachycardia, stress or the use of anesthesia solutions, containing adrenaline, may cause a heart failure. If patient hasbradycardia, use of local anesthetic may provoke the a complete atrioventricular block.  Prevention. Before dental treatment one shoud check the patient’spulse, measurehisbloodpressure, conductdrugpreparationwithsedativesand provide an adequate anesthesia with anesthetics that do not contain adrenaline.If the patient’s heart rate is below 50 beats per minute and there is an atrial fibrillation, extrasystoles, the choice of anesthesia should be chosen after consulting a therapist.

4. Hypertension (consistently high BP,  systolic pressure over 145-160 mm or diastolic over 95 mm of mercury). While being treated by a dentist,the patient may experience a hypertensive crises or acute heart failure. Prevention. Provide premediaction with sedatives, regulateBP withthe help of medicines, an adequate anesthesia with anesthetics that do not contain adrenaline. Ifnecessaryoneshouldusepreparations that contain adrenaline in concentration of 1:200000 (UltrakainDS) andlowerwith precautions for intravascular injection (aspiration test). 

5. Hypotension.DecreasedBP (systole is less than110mm for men and 100 mm for Women, diastole is less than 65 mm.).During the dental intervention one may experience fainting, collapse, shock and use of sedatives could further reduce BP.Prevention.Beforethetreatmentwithmedication, adjust blood pressure, inject atropine sulfate 0,1% or metatsyn sulfate 0.1%up to1 ml depending on heartbeat rate and BP. All dental manipulation aretobedoneafterlayingthepatienthorizontally. While trating one must control patient’s blood pressure.

6. Bronchial asthma.During the dental intervention one can have an asthma attack.because of excitement. Medicationsandmaterialswithwith strong smell maycausebronchospasm. Prevention. Consultation by theraputist. Detailed history taking to identify allergens,that provoke bronchospasm. On the day of treatment recommend the patient to take commonly used medications і bring an appropriate medical nebulizer or inhaler. Local anesthesia is thepreffered type of anesthesia. With heightened sensitivity to Sulphite neveruselocal painkillers withvasoconstrictor because of the fact that they contain bisulfite as a preservativeof vasoconstrictor. Do not use acetylsalicylic acid (The danger of so-called “aspirin asthma”)and other medications, that provoke bronchospasm (morphine, indomethacin).

7. Allergic conditions.Patients that turn to the dentist often have allergic reactions in their medical history, including the ones on local painkillers. The most frequent types of alergesareallergies to local anesthetics (especially groups ofesters likenovocaine), and the ones that are preservatives in carpules, vials (Parabens, sodium bisulfite, etc.). Moreover, allergic reactions can becausedbyantibiotics, sera, dental materials etc.On contacting the allergen an allergic reaction brakes out until development of anaphylactic shock.Prevention.Careful history taking to identify allergic reactions. Particular attention should be given to patients, thatsufferfromallergic and infectious-allergic diseases (rheumatism, collagens, asthma, eczema, etc.) Don’t use the medications that were spotted to cause allergic reactions. If necessary, send the patient for the consultation to the allergy diagnostic department. Useantigіstamіnnі drugs or hormonal agents (prednisolone, hydrocortisone)aspremedication.

8. Anticoagulationtherapy.In case the patient hasaincreased tendency to clot (inpresenceofangina, vascular prostheses, heart valves, etc.) inordertoto prevent thrombosis, the ability of blood to clo is reduced by drugs Heparin, antagonists of vitamin D.).After the operation (Incision, tooth extraction, etc.) bleeding, hematoma formation may appear.Prevention.Pall attention to blood (duration of bleeding, clotting time, etc.).. If the basic parameters of blood coagulation are of appropriate limits, then, after consultation with the therapist, the patient can have tooth extraction, incision of abscess. More complex operations need to be performed only in stationary conditions after correction of clotting. Exclude medications that increase the effects of anticoagulants (Aspirin, fenilbutazon, macrolides and tsefalosporyns).

9. Еpilepsy. An attackof convulsive syndrome can occur in a stressful situationas a result of using local anesthetics.Prevention.Careful history taking to identify convulsive attacks.consultation with the therapistof the patient. On the day of treatment at the dentists the patient ought to takethemedications that he usually needs. Do drug training with sedatives before treatment. Incaseofoftenepilepticseizuresdental interference is to be done during the period of the least density of attacks in a multidisciplinary hospital with resuscitator-anesthesiologist, neurologist. Itisrecommendedtouselocallocal anesthetics of Articaine group (ultrakainDS ultrakainDS-forte, septanest) as they are the most effective.

10. Glaucoma.Adrenaline expands the apple and can trigger an acute attack. Prevention. Local anesthetic drug should not contain adrenaline. For composition of sedation avoid atropine and other M-cholino blockers.

11. Diabetes.dentist must remember the possibility of such patients getting into coma. This may be due to release a large number of blood adrenaline, insulin, which is an antagonist that leads to the development of hyperglycemic coma After surgery, as a result ofangiopathy, reduction of immunological properties of the bodyoccur, observed slow wound healing and development of infection. AsaresultofDisseminated intravascular coagulation diabetics are observed to have early and late bleeding after surgery.Prevention.Before dental interventions of patients with diabetes an advice of endocrinologist is needed.Attentionshouldbepaidonblood and urine analysis concerning sugar. On the day of treatment the patient is  recommended to take commonly used antidiabetic drugs. All dental manipulation are to be done in the morning in1-2 hoursaftermealandinsulineinjection. Dentist needs to know the pecularities of this group of patients (thoroughchoice of tranquilizers for sedation, a good psychological climate at the reception, etc.).For local anesthetic Use drugs without epinephrine or those containing a vasoconstrictor substance, noradrenaline or felipressin. Duringthepostpostoperative prescribe means of chemotherapy to prevent infection, which in turn can cause glucosuria and lead to the development of coma. For patients with decompensated diabetics urgent dental intervention are held only in hospital.

12.Thyrotoxicosis.Thepatientswiththispathologyareextremelysensitivetostressandpain.As a resulteven tooth removal may cause a worsening thyrotoxicosis with the development of thyroid crisis, coma with complete loss of consciousness. Becauseof thyrotoxicosis dysfunction of other endocrine glands is possible, First of all it is adrenocortical function. This can lead to hypocorticism  and patient’s death even with dental intervention.Prevention.Together with the endocrinologist before dental treatment cut off or significantly weaken thyrotoxicosis using medications do drug preparation with sedatives (aminazin 5% – 1 ml intramuscularly or sybazon 0.005 2 times a day inside). Suchpatientsaresensitivetoadrenalin, that’s why it should ne excluded from anesthetic solutions.

13. Hypothyroidism.Patientstendtohavecomplications(colds, secondary infections during surgical intervention). Asaresultofthefactthatduringhypothyroidism the function of other endocrine glands gets disrupted (especially adrenal), inadequate reaction to dental intervention is possibleand cab even lead to death. Prevention. Mandatory consultation with endocrinologist. in case of  affected forms of hypothyroidism dental intervention should be done in hospital together with complex treatment of this decease. Multiple tooth removing is not recommended.

A list of drugs needed for emergency aid at the dentists room

For rendering an effective medical assistance at the dentists room it is necessary

to have a set of medications. Here is the list represented by nosological forms.

Dental emergencies

Most oral emergencies relate to pain, bleeding, or orofacial trauma and should be attended by a dental practitioner. However, in the absence of access to dental care, a medical practitioner may be called on to help. Jaw fractures require the attention of oral or maxillofacial surgeons.

DENTAL PAIN

Pulpal pain is spontaneous, strong, often throbbing, exacerbated by temperature, and outlasts the evoking stimulus. Localization is poor, and pain tends to radiate to the ipsilateral ear, temple, or cheek. The pain may abate spontaneously, but the patient should still be referred for dental advice because the pulp has probably necrosed, and acute periapical periodontitis (dental abscess) will probably follow. Endodontics (root canal treatment) or tooth extraction is required.

Orofacial swelling in a patient with an acute dental abscess

Periapical periodontitis pain is spontaneous, severe, persists for hours, is well localized, and is exacerbated by biting. The adjacent gum is often tender to palpation. An abscess may form (gumboil), sometimes with facial swelling, fever, and illness. Fascial space infections are fortunately rare because they threaten the airway: patients should be referred to a specialist (see box). In the absence of immediate dental attention, it is best to incise a fluctuant abscess and to give antimicrobial agents (such as amoxicillin) and analgesic medication. The acute situation usually then resolves, but the abscess will recur because the necrotic pulp will become reinfected unless the tooth is endodontically treated or extracted. A chronic abscess, however, may be asymptomatic apart from a discharging sinus. Rarely, this may open on to the skin.

Chronic dental abscess at a typical site, in this case, related to the broken molar

Dental sinus opening on to skin

BLEEDING

Most oral bleeding results from gingivitis or trauma, but if it is prolonged, the patient should have an evaluation for a bleeding tendency.

Trauma

After a tooth is extracted, the socket bleeds normally for a few minutes but then clots. Because clots are easily disturbed, patients should be advised not to rinse their mouth, disturb the clot, chew hard, take hot drinks or alcohol, or exercise for the next 24 hours. If the socket continues to bleed, a gauze pad should be laid across the socket and the patient bite on it for 15 to 30 minutes. If it continues to bleed, a hemostatic agent (such as Surgicel) should be placed in the socket. If the bleeding continues, the socket should be sutured and consideration given to a bleeding tendency.

SURGICAL COMPLICATIONS

Postextraction pain

Some pain and swelling after tooth extraction are common but ease after a few hours. Acetaminophen usually provides adequate analgesia. Pain from complex procedures may last longer and should be controlled with regularly administered analgesic agents. If pain persists or increases, the patient should return to the dentist to exclude a pathologic disorder (such as dry socket or jaw fracture).

Infection

Localized osteitis (dry socket) occasionally follows an extraction, typically a lower molar extraction. After 2 to 4 days, there is usually increasing pain, halitosis, unpleasant taste, an empty socket, and tenderness. The clinician should exclude retained roots, foreign body, jaw fracture, osteomyelitis, or other pathologic condition, especially if there is fever, intense pain, or neurologic signs such as labial anesthesia. The infection is treated by irrigation with warm (50°C) saline solution or aqueous chlorhexidine, after which the socket is dressed (several concoctions are available), and the patient given analgesic medication and an antimicrobial agent (metronidazole).

Actinomycosis is a rare late complication of extraction or jaw fracture and usually presents as a chronic purplish swelling. A 3-week course of penicillin is often indicated.

Purplish swelling characteristic of actinomycosis

Antral complications

If the patient has loss of a tooth or root into the antrum, an antimicrobial agent and a nasal decongestant are given and the object located by radiography. A further operation is required.

Patients in whom an oroantral fistula develops should be cautioned not to blow their nose. An antimicrobial agent and nasal decongestants are helpful. If a fistula is detected early, primary closure is possible, but others may need flap closure by a specialist.

Oroantral fistula after extraction of an upper molar. The antral floor is often in close proximity to the roots of maxillary molars and premolars

FRACTURED TEETH

Injuries to the primary teeth may be of little consequence with regard to emergency care, but even seemingly mild injuries can damage the permanent successors. As many as 30% of children have damaged permanent teeth by the age of 15 years.

Enamel fracture of permanent teeth needs no emergency care, but dental attention should be sought later. More severe injuries affecting the dentine should be treated as urgent because there might be pulpal infection. Emergency care consists of placing a suitable dentine lining material onto the fractured dentine, so prompt treatment by a dentist within the same working day or at least by the following morning is required. Fractured roots require dental advice.

AVULSED TEETH

Avulsed permanent anterior teeth can be replanted successfully in a child, particularly if the root apex is not completely formed (children younger than 16 years). Avulsed primary teeth should not be replanted. The younger the child and the sooner the replantation, the better the success; teeth replanted within 15 minutes stand a 98% chance of being retained after further dental attention.

Oral and dental trauma after a skateboarding accident

Immediate replantation gives the best results. Hold the tooth by the crown (do not handle root as that could damage the periodontal ligament). If the tooth is contaminated, rinse it with a sterile saline solution, and if the socket contains a clot, remove it with saline irrigation. Replant the tooth the right way round (ensuring that the labial [convex] surface is facing forward) and manually compress the socket. Splint the tooth; “finger crimping” a foil milk bottle top is a temporary measure, and an alternative is tissue adhesive. The child should see a dentist within 72 hours.

If immediate replantation is not possible, the tooth should be placed in an isotonic fluid (cool fresh pasteurized or long-life milk, saline solution, or contact lens fluid). Otherwise, if the child is cooperative, the tooth should be placed in the buccal sulcus and dental care obtained within 30 minutes. Unsuitable and slightly damaging fluids are water (because of isotonic damage as a result of prolonged exposure), disinfectants, bleach, and fruit juice. The use of a doxycycline immersion before reimplantation by the dentist may be helpful in preventing later external root resorption.

The tooth should be splinted for 7 to 10 days, with no biting on splinted teeth, soft diet, and good oral hygiene.

During follow-up, the patient should be examined for root resorption, ankylosis, and tooth submergence (infraocclusion), which are possible complications.

MAXILLOFACIAL TRAUMA

Dislocation or subluxation of mandible

Dislocation or subluxation of the mandible is commonly caused by a blow to the chin when the jaw is open. The condyles are dislocated forward and upward anterior to the eminence, and the patient gags open.

Fractures must be excluded. Reduction can usually be achieved by facing the patient, placing the thumb pads over the lower molars, and applying downward pressure while, with the fingers under the chin, rotating the jaw backward and upward. If muscle spasm prevents reduction, intravenous administration of midazolam hydrochloride may be needed. After reduction, the patient should avoid wide opening of the jaw.

Recurrent dislocation is a feature of Ehlers-Danlos and Marfan’s syndromes.

Jaw fractures

Jaw fractures result mainly from high-velocity impact as in motor-vehicle accidents, other accidents, and assaults. The immediate concern is to preserve the airway. All traumatized patients should be assessed according to the advanced trauma life support protocol. Other immediate life-threatening problems include intracranial hemorrhage, severe hemorrhage from other sites, and cervical spine damage. During the secondary survey, the head is inspected for lacerations and leakage of cerebrospinal fluid.

Associated bleeding may further compromise the airway. Jaw fractures alone, unless associated with a split palate or gunshot wounds, rarely cause severe hemorrhage. Bleeding from a ruptured inferior dental artery usually stops spontaneously but may recur if, for example, there is traction on the mandible. Severe maxillofacial bleeding may be tamponaded with craniofacial fixation. Bleeding can arise from fractured nasal bones, in which case nasal packing may be required. If bleeding recurs, the damaged vessel must be ligated.

Definitive management of fractures, despite frighteningly severe disfigurement, is not an immediate priority, but debris such as fractured teeth, blood, and saliva should be cleared from the mouth, and the tongue may be controlled by a dorsal suture. An oropharyngeal airway may be required. The maxillofacial team should be involved early on for treatment planning.

Intubation may be necessary in a patient with substantial head injury, and the inability to intubate may necessitate surgical cricothyroidotomy because nasotracheal intubation is contraindicated.

The diagnosis of fracture is from the history, pain, swelling, bruising (hematoma), bleeding (usually intraorally), mobility of fragments (and crepitus), deranged occlusion, paresthesia or anesthesia of nerves involved, and radiographic signs.

Mandibular fractures

Mandibular fractures are commonly due to assault and are usually simple and not associated with other serious injuries or bleeding. If the symphysis is comminuted, the tongue could fall back and obstruct the airway, and this must be prevented. Simple undisplaced fractures may occasionally be treated conservatively with a soft diet if the teeth are not damaged. If the fragments are excessively mobile, pain will be substantial, and early fixation is the best management. Most fractures are managed by open reduction and internal fixation, usually with miniplates.

Step deformity of occlusion revealing mandibular fracture

Middle third or upper facial skeleton fractures

Fractures of the middle third or upper facial skeleton commonly arise from severe trauma (particularly motor-vehicle accidents) and are classified into Le Fort fracture lines:

Le Fort lines of middle third facial fractures

• I: low level above the nasal floor (swelling of upper lip)

• II: subzygomatic (massive swelling of face: ballooning) (Panda facies)

• III: suprazygomatic (massive swelling of face and cerebrospinal rhinorrhea)

There may be airway obstruction, head injury, chest injuries, ruptured viscera, and fractured spine and long bones. Most middle third fractures are treated by open reduction and internal fixation with miniplates.

Zygomatic (malar) fractures

Zygomatic fractures are typically due to assaults. Orbital features are common and include depression of the cheek, lateral subconjunctival hemorrhage, rim-step deformities, restricted eye movements, changes in visual acuity, variation in pupil size and reactivity, and occasionally, enophthalmos or exophthalmos.

Undisplaced uncomplicated fractures need no treatment but should be reviewed as early as possible within 2 weeks. For others, reduction is by elevating from the temporal region (Gillies approach), an intraoral approach, or open reduction and internal fixation.

Summary points

• Emergency treatment of dental abscess is the administration of antimicrobial agents and analgesic medication and drainage of a fluctuant swelling by a dentist; without dental treatment, the abscess will recur

• Emergency care of postextraction bleeding is to have the patient bite on gauze for 15-30 minutes; if it persists, the socket may require packing with a hemostatic agent or suturing. It occasionally signifies an unrecognized bleeding tendency

• Pain increasing after an extraction may indicate infection or fracture, so radiographs should be obtained to exclude a pathologic condition

• Primary teeth should not be replanted, but permanent teeth in children can be successfully replanted; the tooth should be kept clean and moist in saline or milk solution, replanted as soon as possible, and splinted

• A priority in patients with maxillofacial injury is the airway

• Middle third facial fractures may be associated with cerebrospinal rhinorrhea, and zygomatic fractures may be associated with ocular damage; in any case, a maxillofacial team should be involved at an early stage for planning treatment

Local anesthesia (LA) forms the foundation of pain control techniques in dentistry. These drugs prevent the passage of noxious stimuli to the patient’s brain where it would be interpreted as painful. Other techniques of pain control are available, including general anesthesia, hypnosis, acupuncture, and electronic dental anesthesia, but none is as consistently reliable and as safe as LA.

Local anesthetics are used more than any other drugs in dentistry. It is conservatively estimated that in excess of 300 million cartridges of LA.

However, problems can and do occur whenever drugs are administered. Problems noted with administration of LAs may be associated with the drug or some other component of the injected LA solution, the act of administering (injecting) the drug, and localized trauma produced by the needle through which the drug is administered.

In this article, 2 of the major complications associated with the administration of LA are reviewed. These are allergy and overdose (toxic reactions).

THE LA CARTRIDGE

The LA cartridge is a glass cylinder (plastic cartridges of LA are available in some countries) capable of holding 2.0 mL of solution. A thick silicone rubber stopper (plunger) seals one end of the cartridge. As a result, a filled cartridge contains 1.8 mL of anesthetic solution. (In some countries, such as Great Britain, Australia, and South Africa, LA cartridges contain 2.2 mL). The opposite end of the cartridge has a thin latex membrane through which the needle penetrates into the cartridge.

LA cartridges are manufactured using a process that ensures the solution inside the cartridge is sterile; the outside of the cartridge is aseptic. Changes in Food and Drug Administration (FDA) regulations have added a terminal sterilization step to the manufacturing process of the recently released articaine HCl (Septocaine). The composition of cartridges varies dependent upon whether or not a vasopressor is included in the LA solution.

ALLERGY

True, documented, and reproducible allergy to ester-type LAs is relatively common, while with amide-type LAs allergy is such a rarity as to be virtually nonexistent. Reports of “alleged” allergy (eg, “Doctor, I am allergic to Novocain”) are more frequent. Confronted with an alleged LA allergy, the clinician must: (1) always believe the patient and not administer any LA, including (or perhaps, especially) topical anesthetic, and (2) determine what actually happened during their “allergic reaction.” Questions to ask of the patient (dialogue history) are presented in Table 3.

Knowledge of the signs and symptoms of allergy will enable the clinician to quickly differentiate true allergy from the more frequent psychogenic reaction (eg, fainting) or reaction to the vasopressor (epinephrine). When doubt persists in the mind of either the patient or doctor, do not administer any local anesthetic. Definitive allergy testing by an anesthesiologist or allergist may be necessary to determine the true nature of the “reaction.”

Allergy to Components of a LA Cartridge

Though allergy to a LA drug is highly unlikely, allergy may occur to one of the components included in the cartridge.

Methyl paraben was included in dental LA cartridges until the mid-1980s when the FDA mandated its removal. Parabens were included in LA cartridges as bacteriostatic agents, maintaining sterility of the solution. As dental LA cartridges are single-use items, there was no need for the inclusion of parabens. However, whenever multidose vials of LAs (or any drug) are employed, methyl paraben will still be present, and allergy to parabens should be considered.

Another component is the antioxidant sodium (meta)bisulfite, which is present in every dental LA cartridge containing a vasopressor (eg, epinephrine, levonordefrin). Potential allergy to bisulfites should be considered if the patient is an allergic-type asthmatic. Bisulfites are also found in many foods and beverages, including dried fruits, cheeses, and wines. In the presence of a documented sulfite allergy it is suggested that a LA solution without a vasopressor (“plain LA”) be used (eg, mepivacaine HCl 3%; prilocaine HCl 4%). There is no cross-allergenicity between sulfites and the “sulfa”-type antibiotics (sulfonimides). 

Specific mention must be made of articaine HCl, an amide local anesthetic that contains a sulfur molecule in its chemical structure. As the sulfur molecule is an integral part of the thiophene ring of articaine HCl, it is not available to act as an allergen. Articaine HCl may safely be administered to patients with sulfur allergy. Introduced in 1975, and presently available in approximately 131 countries, there have beeo reported cases of allergy to articaine HCl.

Epinephrine Allergy

Allergy to epinephrine cannot occur. Questioning of the “epinephrine-allergic” patient (see dialogue history, above) immediately reveals signs and symptoms related to increased blood levels of circulating catecholamines (tachycardia, palpitation, sweating, nervousness), likely the result of fear of receiving injections (release of endogenous catecholamines [epinephrine and norepinephrine]).

Latex Allergy

The thick plunger (also known as the “stopper”) on one end of the LA cartridge and the thin diaphragm on the other end of the cartridge (Figure 1) through which the needle penetrates may contain latex. As latex allergy is of growing concern among all healthcare professionals, the risk of provoking an allergic reaction in a latex-sensitive patient must be considered. A recent review of the literature on latex allergy and local anesthetic cartridges by Shojaei and Haas⁶ demonstrates that latex allergen can be released into the LA solution as the needle penetrates the diaphragm, but there were no reports or case studies in which an allergic response to the latex component of the cartridge containing a dental local anesthetic was documented.

OVERDOSE (TOXIC REACTIONS)

Overdose (also known as toxic reaction) occurs when the blood (serum) level of LA in either the central nervous system (CNS) or myocardium is elevated to a point where the drug produces potentially life-threatening events. The overdose reaction persists until the blood level of the drug in these “target” organs falls below the toxic level. lists ways in which overly high blood levels can be produced. 

In, the first 3 listings represent the most common causes of local anesthetic overdose in dentistry. 

Intravenous administration may be prevented by always performing an aspiration test prior to and during all LA injections. Of somewhat greater importance is the rate at which the LA is administered. The ideal rate of drug administration is 1 mL per minute. Recommended for dental offices is a rate not to exceed 1 cartridge (1.8 mL) per minute. 

The administration of too large a local anesthetic dose in relation to the age and weight of the patient is the most common cause of serious overdose of LAs in dentistry. Though some serious cases of LA overdose have occurred in adult patients, the overwhelming majority of problems have developed in children, commonly the child who is younger (2 to 6 years), lighter-weight (15 to 40 kg), well-behaved, requiring multiple procedures in 4 quadrants, and managed in the office of an inexperienced general dentist. 

Review of many of the cases that resulted in serious morbidity or death reveals a number of shared factors, none of which by themselves might pose a serious problem, but when taken together act to produce clinical signs and symptoms of LA overdose. Some of these factors are presented. 

As listed in, the factors adding to increased risk of LA overdose in younger patients are…

Treatment plan. In interviews with trained pediatric dentists, I have found that when presented with the patient described above (young, light-weight, well-behaved), the pediatric dentist will not treat all 4 quadrants at one visit using LA. Limiting treatment to 1 or 2 quadrants per visit represents a more rational approach to this patient’s needs, and increased safety.

The dentist who is confronted with a (well-meaning) parent or grandparent who complains of the difficulties of getting to the dental office and the inconvenience of having to miss a half day of work, and wanting to have their child’s dental care accomplished in one visit (not two or more), might feel pressured into agreeing to this request, thus increasing the risk for LA overdose.

Choice of LA. In most instances where serious LA overdose has occurred in children, the LA administered has been a “plain” drug, either mepivacaine HCl 3% or prilocaine HCl 4%. Both of these are excellent LAs when used properly. The rationale behind the clinician’s selection of a short-acting drug for children includes: (a) most pediatric appointments are of short duration, and (b) plain LAs have a shorter duration of posttreatment soft tissue anesthesia, minimizing the likelihood of inadvertent soft tissue injury as the child bites or chews his/her numb lip or tongue.

As a rule, the pediatric dentist will administer a plain LA only when treatment is limited to one quadrant. When treatment extends to 2 quadrants or more in one visit, a vasopressor-containing LA will be selected. Prolonged post-treatment soft tissue anesthesia does lead to the increased possibility of soft tissue damage, however, this risk is far outweighed by benefits accrued through delayed absorption of both the LA and vasopressor into the cardiovascular system (the risk of overdose is diminished). There are many ways of preventing postoperative soft-tissue injury, such as securing a cotton roll in the buccal fold and advising the parent to watch the child.

Volume of LA administered. Pain control for the entire primary dentition can be achieved with approximately 2 cartridges of LA. In the child patient, there is never a compelling reason to administer a full 1.8 mL cartridge of LA for any 1 injection. Yet, when children receive LA administered by nonpediatric dentists, full cartridges tend to be routinely administered. In many of the instances where death resulted, a total of 5, 6, or 7 cartridges were administered.

In cases where LA must be administered to all 4 quadrants of a younger child, this can be achieved with no more than 2 cartridges, as follows: either one-quarter cartridge each for the right- and left-incisive nerve blocks (anesthetizing all mandibular teeth), or one-third cartridge each for right- and left-inferior alveolar nerve blocks; and one-third cartridge each for the right- and left-anterior superior alveolar nerve blocks. In lieu of the anterior superior alveolar nerve block, maxillary infiltrations may be administered with one-sixth cartridge per injection.

LA administered to all 4 quadrants at one time. The administration, over 1 or 2 minutes, of 4 or more cartridges of a LA without a vasopressor to all 4 quadrants makes little therapeutic sense, while increasing the likelihood of an overdose. Administration of LA to one quadrant, treating that area, then anesthetizing the next quadrant, and so on, makes considerably more sense both from a therapeutic and safety perspective. For equal amounts of LA, administration over a longer timeframe (1 to 2 hours) will result in a lower blood level of the LA as compared to the entire dose being administered at one time. Exceeding the maximum dosage based on patient’s body weight. An important factor, especially when managing younger, lighter-weight patients, is maximum dosage. Determine the weight of the patient (in pounds [lb] or kilograms [kg]) prior to the start of treatment. It is preferable to weigh the child on a scale, as parents frequently can offer only a rough estimate of the child’s weight.Maximum recommended dosages of commonly administered LAs are presented. 

The intrinsic safety of LAs is illustrated in, which presents the volume of LA administered on 65 occasions by a general dentist who removed third molars from college-aged individuals. None of these patients experienced an adverse response to the LA although many received dosages 2 or more times maximum recommended dose.10 This is one indication that local anesthetics are extremely safe drugs, when administered to healthy, adult patients. Unfortunately, when administered in overly large doses to younger, light-weight patients, overdose is a significant risk.

Virtually all LA overdose reactions are preventable if the clinician adheres to the very basic, simple recommendations presented above. In the unlikely situation where an overdose reaction develops, adherence to the basic steps of emergency management  will lead to a successful outcome in virtually all cases.

 LAs are the foundation of pain control in dentistry and are used to reversibly block peripheral nerve conduction. It must always be remembered that all drugs have the potential to do harm. All dentists and hygienists permitted to administer LAs must be aware of these potential problems and be prepared to manage them expeditiously and effectively.

Unfortunately the allergies in dentistry are also well-known, most materials we use are risks for the sensitive people. The materials used in mouth, besides their destiny to be worn constantly and get into permanent contact with the mouth have to bear a special wet medium, the saliva, with a constantly changing reaction, and full of bacteria.

Regarding that practically any substance can be a potential risk, ARS DENTAL endeavors to customize the variation suitable for our patient. In what follows we wish to provide alternatives shortly – avoiding the amply scientific explanation – in case the patient has allergy and we present the certain substances that come along with certain procedures and the test result issued by the dermatologist will be instantly understandable for everyone.

Symptoms of allergy:

• skin reactions: itching, rush, tympany, red, scaling dried skin, eczema

• oral mucous membrane symptoms: burning-pecking feeling, metal-taste sensation, full-bloodedness, cracking of mucous membrane

• inflammation or airways: pharynx inflammation, asthma

• general symptoms: weakness, diarrhea, nausea, dizziness

• eye: conjunctivitis, eye itching, tearing, eye dryness

• hair loss

• stomach-, intestine symptoms

 Diagnosing allergies:

The diagnosis of the allergies are done by dermatologist either to certify the existing allergy or to prevent it in better cases. Before bigger dental intervention it is advisable to turn to dermatologist so that we can make sure which substances can get into the mouth safely. (On the long run it can be beneficial both from health and material point of view).

There are two general testing methods to establish the presence of the allergies. One is the epicutane test the other is the lymphocyte-transformation test.

1) During the epicutane test certain metals or test substances containing their chemicals are put onto the skin one by one and fixed with a special plaster. The possibly formed transformation type and size can help to deduct the sensitivity to certain substances.

2) The lymphocyte-transformation test is based on the fact that the allergens induce the production of T-lymphocytes that activate at the repeated meeting with the substance. This procedure is realized in-vitro, thus the activity is measurable by blood test in case of sensitivity to the given material.

AMALGAM

 

It is a frequently debated question: toxic or not toxic. One thing is certain, the point of ARS DENTAL is that we have not used the substance for 15 years. It is a fact, though, that the salt of the quicksilver (chloride or ammonium) can cause over sensitivity. Against the quicksilver the body produces IgE and IgG type antimatters. The IgG antimatter accumulate in the kidney causing kidney failure that can play a role in the kidney toxicity of the quicksilver. (It is interesting that in case of gold-sensitive people quicksilver sensitivity is shown, too. This suggests the possibility of cross-allergy between the two metals that is also enforced by animal experiments). That can aggravate the situation if there is another metal in the mouth besides the amalgam (See below: Galvanism) 

COMPOSITES (tooth-colored filling materials)

These filling materails with outstanding aesthetic qualities seem to be better alternatives: we have to sacrifice less teeth material as the y bound well to the gap walls, they have reasonable prices with good mechanical parameters, and can be prepared quickly, etc. Unfortunately we have to be careful: composites contain bis-GMA that can trigger oversensitive reactions in case of sensitive people.

Unfortunately, the price of the safest golden work is quite high and have no other aesthetic alternative. There are attempts to produce the bis-GMA free substances, but according to the technical literature those are even less safe. There are promising attempts at the present for the use of Zirconium (see below) in this way, but without concrete result.

The most we can do and we do is – by following the recommendation in the technical literature – we light up the fillings in multiple small details, thus its binding will be more perfect and the bis-GMA cannot solve easily. This is a reason why the filling is not ready in 5-10 minutes at the ARS DENTAL.

GOLDEN INLAYS AND FRAMES

The use of golden alloys:

• Golden inlay

• Crown, bridge frame

• Removable denture frame, precision anchorage tools 

 

Though the materials of the golden inlays used as an alternative to the filling not exactly identical with the alloys of the golden frame, in case of allergy we do not make mistake to discuss them together. The gold is still a classic today, besides its outstanding qualities it is antibacterial, lasting and excellent replacements can be made of them. They are debatable from aesthetic perspective and expensive, but they rarely trigger allergic reactions. Allergies may possibly occur to the alloy materials, however pure gold does not have the proper physical qualities (toughness, resistance to wearing, melting pint, etc.) to be suitable for dental use.

We use a softer gold alloy to the inlays and one that has higher platinum content to the replacements. The gold content, depending on the area of use, is about 70-90%. Other alloy materials beside the platinum are palladium, silver and copper.

 Galvanism

We must also mention the question of galvanism. If we wear more metal sin the mouth (e.g amalgam filling, golden inlay, crowns, bridge frames, removable dentures or piercings containing different alloys) then those form a cell in the saliva owing to the electric potential between them.

For this reason ARS DENTAL uses nickel-freee metal for the metal-ceramic bridges.

Unfortunately though, in case of the nickel the cross allergy can be observed to the chrome, cobalt, platinum, palladium, copper or other metals that are the basic components of dental metals, thus we can only prevent one danger. About 3% of the population is allergic to the chrome. Among the men it is 4%, and 2% among the women. 40% of the sensitive people is sensitive to the cobalt, too. These are not very encouraging statistics and moreover they seem to deteriorate with the years.

An alternative is the ceramic replacement burnt on gold or the presently most promising material the Zirconium ceramics that seems to be a breakthough in dentistry.

THE RAW MATERIAL OF THE REMOVABLE, METAL FRAME TOOTH REPLACEMENT: THE COBALT-CHROME ALLOYS

Dental alloys with good toughness, thus it is possible to make gracile moldings from them. In a smaller proportion they contaiickel, molybdenum, and may contain iron, manganese, silicium, aluminum, tungsten.

They are alloys with good mouth bearing, though allergy can occur against any component. If this is proven by allergy test, we have to find the metal that is tolerable for the patient.

Alternative can be the gold alloy as a frame or in certain cases the acrylate removable denture.

In the Implantation denture there is further information about the possibilities of transforming removable cases into fixed, cemented replacements when this alloy can be avoided.

SILVER-PALLADIUM ALLOYS

It was previously used as the frame of quality plastic bridge replacements, for today its use is decreased. In 10% it can contain other metals, like copper, gold, nickel, chrome, manganese, stannic, cadmium, magnesium.

Zirconium DIOXIDE

Certainly the above mentioned problems lead to the introduction of Zirconium into dentistry, that proves to be the best material used so far. This material long used and experienced in medicine is the ’savior’ in our allergy-stricken world. Besides triggering no allergic reactions, its mechanic qualities are outstanding and regarding the fact that it is not a metal, it does not attract plaque onto its surface thus it is perfectly tissue friendly with the gum. It is only an extra that it has a far outstanding aesthetic quality. As ARS DENTAL endeavors that our patients could wear the most perfect and aesthetic replacement, we are providing an artificially low price for this replacement.

This material is not only the material of bridges and crowns, but implants and constructions are also prepared from it, therefore it stands its place even in the bone in surgical circumstances and absolutely metal-free ceramic replacements can be prepared. Owing to its relatively high price, this latter one is important when the aesthetic expectations are very high or the patient has a rare titanium allergy.

THE MATERIAL OF THE IMPLANTS IS THE TITANIUM

The titanium is almost absolutely tissue neutral and also neutral from galvanic perspective. Allergy to titanium is very rare. In general surgery it has been used for decades. The material we use is pure titanium, thus it is unique as there is no other metal that can be used for dental replacements in their unalloyed form. The surface of the titanium implants is a stabile compound, the titanium-oxide. This material do not dissolve in body fluids, thus in theory do not get into reaction with the immune system. As head part titanium can be chosen or Zirconium for higher aesthetical purposes.

Regarding that the implants are planned for longer lifespan during which they function fixed into the bone and their insertion requires a surgery and, alas ther extraction, too, and they require large financial investment as well, ARS DENTAL recommends that before the surgery you should ask for an allergy test from your dermatologist. Unfortunately in recent years there have been reports in the technical literature about the questions regarding biological stability of the titanium. 0,2-1% of the patients applying for implantation showed titanium allergy, and this occurs among patients who have other metal allergies usually. In this case Zirconium implants can be a solution.

THE RAW MATERIAL OF THE REMOVABLE DENTURES: ACRYLATE

We do not only have to consider the allergic reactions triggered by the metal sas we have already mentioned at the tooth-colored fillings. It is known that the certain components of the traditional acrylates, like the monomer or the acrylate itself can offer trigger allergic reaction and unpleasant feeling. However it is important to add that in the background of the removable denture-caused full-blooded or ulcerous distortions can be mechanic causes, we do not have to consider allergy. In problematic cases, though, we have the dental allergy test on our disposal.

Acrylates can be used for partial and complete removable replacements, covering traditional plastic bridges, crowns.

In case there is an allergy to acrylate, alternative solution can be the thermoplastic materials that do not contain monomers or acrylate, but are more tissue friendly. This is a reason why the thermoplastic prosthesis is easily adaptable for the majority of the patients. There is also a possibility to transform the given situation into fixed replacement with the help of implantation, thus, acrylate is not needed.

Allergies to metals (elements) and metallics (alloys – compounds of two or more metals) can cover a lot of ground and really can open the proverbial can of worms. So let’s give you a short overview for the sake of clarity. Allergy is a response of the body’s immune (resistance) system that recognizes substances, whether living or non-living. Four types of allergic reactions are known which includes initiation of a specific (antibody) response to the offending entity. When the normally protective immune system, which defends us from bacteria, viruses, pollens and more causes an exaggerated response that is not protective, it is known as allergy. Allergic responses can be as minimal as a mild rash to, in rare cases, death from a multi-system shutdown known as anaphylaxis (“ana” – without; “phylaxis” – protection). You can become allergic to virtually anything, and at any time, including metals.

It has been reported previously that more than 5% of the population experiences allergic reactions to metallics. More recently, it has been reported that 17% of women and 3% of men are allergic to nickel and that 1% to 3% of the people are allergic to cobalt and chromium. Among dermatitis patients, (“dermat” – skin; “itis” – inflammation), the prevalence of metal allergy is even higher. Environmental exposures to metallics include jewelry, buttons, clothing fasteners, dental restorations, mobile phones, and more. Consumer exposure is responsible for most cases of metal allergy, even more than occupational exposure. Traditionally, nickel, cobalt, and chromium have been the most important contact allergens. However, recently, gold and palladium (primarily alloys that contain more than one metal) have drawn more attention, as the prevalence of contact allergy to these alloys is recognized. In the United States, studies show that the prevalence of nickel allergy is increasing. Furthermore, metal allergy has been associated with some device failures following placement of stents into coronary (heart) blood vessels, hip and knee prostheses, as well as other implants. These numbers are relatively small when compared with numbers of applications, however more research is needed in this area.

The American Dental Association (ADA) reports that, for many years, the only available choices for dental fillings were metals and alloys. Traditionally, these were gold alloy or “amalgam,” a mix of approximately 43% to 54% mercury with other metals, including silver, copper and tin. Because of the development of other “tooth colored” materials today, amalgam is used most commonly in the back teeth. It is one of the oldest filling materials, used and improved upon for more than 150 years, and is the most thoroughly researched and tested filling material. In rare cases, a localized allergic reaction such as inflammation or rash may occur with its use.

That gets us to the topic of dental implants. Dental implants are generally made of commercially pure titanium or titanium alloy. One aspect of titanium and alloy is that they are osteophilic (“osteo” – bone; “philic” – loving) and therefore very biocompatible. Because of this, dental implants have had a truly amazing track record of success. A recent study in Clinical Oral Implants Research reported that in dentistry, allergic reactions to titanium implants and the associated intraoral prostheses have not been studied in great detail. However, placing metallic dental implants and associated restorations can potentially provoke allergic reactions. The study, involving 1,500 patients, reported that titanium allergy could be detected in dental implant patients, even though its estimated prevalence is low (0.6%). A significantly higher risk of positive allergic reaction was found in patients who had lost implants for no other known reason other than that they had a higher incidence of allergy, in which case testing could be recommended. However, this issue is confounded by the use of many different metallics and other materials as a part of the overall implant construction.

As for replacing your missing tooth, a dental implant is an excellent long-term option, given today’s advanced knowledge about dental and oral health. The ADA states that, whenever something foreign is put into your body, there is a chance of side effects. Thus all biomaterials (implants) and other dental materials used in the mouth may cause localized allergic reactions in a very small number of individuals. This is why your dentist needs to know about your allergies. It may be an important part of determining what the right material is for you. We hope that you receive the tooth you want and deserve without any fear of metal allergies.

Local anesthetics (LAs) are drugs widely used in clinical practice having revolutionized modern medicine from both the diagnostic and therapeutic point of view. In the first case, these drugs are used for patients’ preparation for different procedures (endoscopic, radiologic etc.) whereas in the second case they provide anesthesia for surgical interventions. As such, these agents are commonly administered in dental practice.

LAs were discovered in 1884, by a young Viennese ophthalmologist, Carl Koller that instilled cocaine, a natural agent, in his conjunctiva obtaining an anesthetic effect. A few years later, the first synthetic anesthetic Procaine, was produced.

As LAs have been widely and increasingly used since last century, different LA agents have been synthesized. LAs can induce adverse reactions following their administration. In particular, allergic (hypersensitivity) reactions to local anesthetics have been reported; although these reactions are rare, in some cases the problem seems over-estimated being responsible for frequent therapeutic abstaining.

Therefore, this communication aims to point up the pathogenic and clinical aspects of hypersensitivity reactions to local anesthetics in order to offer a “model of behavior” for dentists who may face different adverse reactions induced by LAs in the daily clinical practice.

Pharmacology

LAs have similar molecular configuration with a lipophilic aromatic ring connected to a hydrophilic amine group. The type of linking bond is used to classify these drugs into ester and amide groups. Ester are all derivatives of para-aminobenzoic acid (PABA) and include cocaine, procaine, tetracaine, benzocaine e chloroprocaine. The amide group, actually the most frequently used in clinical practice, includes lidocaine, mepivacaine, etidocaine, prilocaine, bupivacaine and dibucaine.

Mechanism of action

LAs induce an anesthetic effect by blocking nerve conduction, thus blocking afferent nerve signals to the brain. Nerve conduction blockade is obtained by a reversible binding of the anesthetic drug to the voltage gated sodium channels present in the nerve cell membrane, blocking therefore the formation of action potentials. The lipophilic nature of the LA facilitates diffusion across cell membrane and binding inside the cell.

  Metabolism

Ester LAs are rapidly hydrolyzed by plasma cholinesterases, except cocaine which is metabolized by the liver. PABA is an intermediate metabolite, unable to induce anesthesia but it is a known allergen. It must be mentioned that parabens are widely used as additives in several lotions, cosmetics and foods. Thus, patients with hypersensitivity reactions to parabens can cross-react to PABA, if they are injected by LAs of the ester group. These phenomena can be at the basis of the higher prevalence of allergic reactions to ester compared to amid anesthetics. In fact, the incidence of hypersensitivity reactions to LAs has been drastically decreased since 1950, when the amide group has been introduced.

Amides undergo liver metabolism and renal excretion. In patients affected by liver failure it is therefore prudent to pay attention in order to reduce the total dosage of LA administered. Similarly to esters, some amides may also contain preservatives, such as sulphites and methyl-parabens, both chemically similar to PABA and therefore can cause allergies in sensitized individuals.

In conclusion, the ester group is more frequently implicated in allergic reactions compared to the amid group. In addition, different esters can cross-react within the ester group. The cross-reactivity is not reported between esters and amides.

Adverse reactions to LAs

Drugs used for local anesthesia may provoke adverse reactions caused by different pathogenic mechanisms, that in most cases can be only suspected but rarely demonstrated.

These reactions can be distinguished in two groups: toxic reactions and hypersensitivity reactions.

Toxic reactions may be observed depending on the way of administration of the compound, the site of injection (accidental intravascular injection) and the clinical conditions of the patient (kidney or liver failure). Thus, the risk of toxic reactions could be significantly minimized staying within safe dosage parameters and using safe injection techniques. The symptoms of toxicity can be important and include agitation, tremors-convulsion, bradycardia and eventually cardiovascular collapse and respiratory depression.

It should be noted that vasoconstrictors such as adrenaline are frequently associated to the LA injection in order to lengthen anesthesia duration and make the site of surgical intervention ischemic. The administration of adrenaline can induce different signs and symptoms: tachycardia, hypertension, convulsions, loss of consciousness. More often, these events rely on an exaggerated individual response or on a rapid intravascular passage as in case of an accidental intravascular injection.

More frequently, hyperventilation, nausea, vomit, sweating, dizziness or light bradycardia following LA injection may be reported . These reactions -often mimicking allergic reactions- are autonomic reactions.

Hypersensitivity reactions to LAs

Mook described the first report of allergic type reaction to LA in 1920 in a dentist who developed eczema on his hand after handling apothesin, a congener of procaine Hypersensitivity reactions to LAs make no more than 1% of LA reactions. However, these reactions may be clinically important as they are unexpected and potentially serious. Based on Gell & Coombs classification, hypersensitivity reactions can be distinguished in: immediate (type I) or delayed (type IV).

     Type I reactions are mediated by the interaction between specific antibodies of the IgE class, produced following exposure of a sensitized subject to various antigens/allergens (drugs, pollens, foods etc.). The following exposure of the patient to the same allergen induces interaction between two IgE specific molecules and the high affinity receptors for IgE (FcεRI) present on the cell membrane of mast cells and basophils. Mast cells and basophils are namely the primary effector cells of allergic reactions. Activation of these cells is characterized by a series of enzymatic and structural intracellular changes inducing histamine release and production of vaso-active mediators (leukotrienes, prostaglandines, PAF, tryptase, chymase ecc.), cytokines and chemokines responsible for the clinical manifestations of allergic reactions.

From the clinical point of view, signs and symptoms may vary and different organs and systems may be involved. Skin manifestations such as urticaria with pruritic rush, often associated to angioedema (lips, tongue, eyelid etc.) may be present. Respiratory symptoms may vary from rhinorrea to bronchospasm whereas cardiovascular symptoms such as severe hypotension may dominate the signs. In this context, systemic anaphylaxis represents without doubts, the most critical and dramatic clinical event within the scenario of hypersensitivity reactions. Anaphylactic reactions may be characterized by clinical symptoms of different grading of severity

Grading of severity of anaphylactic reactions

Although principal targets of anaphylaxis are cardiovascular, respiratory and gastrointestinal systems and the skin, these may be involved separately or in combination. Thus, it is important to understand that signs and symptoms considered “minor” may not be always present before the involvement of the respiratory and cardiovascular systems. In some cases, typical signs such as tachycardia, often considered a characteristic sign of systemic anaphylaxis, may not be present.

Allergic reactions mostly elapse like a unique event within minutes or a few hours from drug administration, but in some cases clinical manifestations may be present even after many hours from the initial event or they may have a prolonged duration (> 24 hours).

In some cases, a pseudo-allergic mechanism may be involved, induced by the activation of complement components following exposure to exogenous antigens (drugs, radiographic contrast media) or endogenous antigens (tryptase) with formation of anaphylatoxins. The later can directly induce degranulation of the primary effector cells (mast cells and basophils) of allergic reactions. From the clinical point of view these manifestations can’t be distinguished from anaphylactic reactions.

Type IV hypersensitivity reactions to LAs are basically induced by contact through the skin with subsequent manifestation of eczema lesions often involving the hands. These reactions appear after a prolonged period of exposure to the drug and may be secondary to the release of histamine by non IgE- mediated mechanisms.

Parallel to hypersensitivity reactions to LAs, reactions induced by preservatives -metabisulphites and parabens- contained in commercially available LA preparations have been reported. Metabisulphites are present as anti-oxidants, in different concentrations, in preparations containing adrenaline. These compounds are widely used in food industry, being contained as additives in different foods (wine, beer, etc.) and are marked as E221-E227. Metabisulphites may cause non IgE-mediated hypersensitivity reactions, characterized by rhinitis, rush, headache, dyspnoea, cramping.

Parabens, are rarely used as preservatives in different preparations of local anesthetics and can induce hypersensitivity reactions of type I and IV. Methylparabens and propylparabens are metabolized in chemical components structurally similar to PABA.

A correct evaluation of patients at risk of hypersensitivity reactions to LAs is necessary for their prevention and/or management.

Subjects at risk of hypersensitivity reactions to LAs are considered those who experience one or more of the previously described clinical manifestations during or following injection of a LA agent. Thus, a detailed history is an essential first step towards an accurate diagnosis. In some cases, in the base of symptoms reported by the patient (agitation, sweating, nausea, bradycardia), it may be possible to suspect an adverse autonomic reaction excluding an allergic sensitization.

It is important to underline that atopy is not a risk factor for the majority of allergic drug reactions. This means that patients affected by allergic diseases such as bronchial asthma, allergic rhinitis, food allergy etc., are not at higher risk for hypersensitivity reactions to drugs, compared to non atopic individuals. However, patients affected by chronic diseases (bronchial asthma, cardiovascular diseases etc.), may have a more severe course of allergic reactions due to the diseases’ nature and to the therapy administered (β-blockers or ACE-inhibitors ) for their treatment. Therefore, patients affected by chronic diseases must be adequately controlled and β-blockers or ACE-inhibitors therapy should be suspended before surgery.

In differential diagnosis of hypersensitivity reactions to LAs, allergy to various agents used during anesthesia in dental practice (chlorexidine, latex etc.) should be considered. Similarly, drug allergy induced by antibiotics and/or FANS, administered to patients before or during dental interventions should be examined.

In case of previous hypersensitivity reactions to LAs the patient should be referred to a specialist (allergist) to perform specific challenge tests in order to identify which LA should be used for future surgery.

When evaluating a patient for LA allergy, it is essential to obtain a detailed history including the LA used previously and a description of the reaction. The Joint Council of Allergy, Asthma, and Immunology (JCAAI) recommends that if the LA that caused the reaction in a patient is known, the specialist should consider for skin testing a LA of another class: for example if an ester caused the reaction, than an amide LA should be used for testing. If an amide is involved, then another amid may be tested, as there has not been reported cross-reactivity between amid groups (1). LAs used for testing should not contain preservatives and adrenaline that may alter skin reactivity.

Testing should be performed in the hospital where in case of severe hypersensitivity reactions therapeutic interventions can be immediate.

The incremental dose challenge test protocol is the following:

1. Prick test with undiluted LA

2. Intra-dermal injection with diluted LA in increasing concentrations (1:100, 1:10, 1:1)

3. Subcutaneous injection with undiluted LA in increasing concentrations (0,1 ml, 0,3 ml, 0,5 ml).

Injections are repeated every 15 minutes.

After the last injection, patients remain under clinical observation for approximately 2 hours.

The performance of alternative skin tests or in vitro tests without the for mentioned incremental dose challenge test are not safe and efficacious.

It should be mentioned that even in case of a negative challenge test, it is not possible to exclude the possibility of non IgE-mediated reactions. Thus, in case of patients with documented adverse reactions to LAs and negative challenge tests, it is necessary to prescribe a preventive therapy to administer prior to the LA injection .

In the clinical practice, the use of the following pharmacologic protocol, has demonstrated efficacy in reducing the incidence and severity of hypersensitivity reactions to local anesthetics: 

48, 24 and 2 hours before dental surgery:

CETIRIZINE 10 mg

RANITIDINE 300 mg

13, 7 and 1 hours before dental surgery :

PREDNISONE 25 mg

1 hour after dental surgery:

CETIRIZINE 10 mg

RANITIDINE 300 mg 

Concluding remarks

LA agents, have revolutionized our ability to provide surgical interventions in a pain-free manner .

The classification of LAs in two groups, esters and amids, is based on their structural and metabolic characteristics. Esters can more frequently induce allergic hypersensitivity reactions. Amids, are less allergenic and not significantly cross-reactive. They are widely used in clinical- surgical practice.

As 1% or less of the reactions to LAs are truly immune system mediated (type I or type IV), the problem of allergic reactions to LA appears often over estimated in dental practice and frequently induces to therapeutic abstaining.

Challenge skin tests with incremental doses of LA, preservative and adrenaline-free, performed by the specialist, are currently considered the gold standard, shown to be efficacious and safe in the evaluation of LA allergy. Challenge tests should be performed in patients with documented previous adverse reactions to LAs.

The best therapy for allergic, hypersensitivity reactions including anaphylaxis is prevention. Thus, patients at risk should be rapidly recognized in order to prevent or possibly attenuate severity of allergic reactions.