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ePaper created 2016-02-02, 09:16:44 | version 1.38.0
science & practice 16 AEEDC Dubai 2016 The last two decades have seen significant advances in restorative techniques and materials for den- tistry.Thelatter,alongwithcommu- nity-based preventive measures that aim to reduce the incidence of caries, have resulted in many pa- tients living with functional teeth foralongerperiod.Yet,extractionof teethformstheconsiderablebulkof the workload in oral surgeries ow- ing to several factors, including the late presentation of patients with advanced dental disease, the pres- ence of symptomatic impacted teeth, such as third molars, and the needtoextractteethfororthodontic or orthognathic treatment. The extraction of teeth varies greatly based on the type of patient who is undergoing the procedure. For example, elderly patients with significant co-morbidities and on a complex combination of medica- tions as compared with young healthy individuals render the pro- cedure complicated and require much more preparation with modi- fications during and after patient management. Additionally, extrac- tions can range from a single, fully erupted tooth with favourable mor- phology to multiple misaligned, im- pacted teeth or teeth with challeng- ing morphology. Local anatomy, such as tooth proximity to the nerve,maxillarysinusandtuberos- ity, also plays a significant role. These variations usually dictate who is to perform the extraction, as many general practitioners deal with less complicated cases of den- tal extraction in individuals re- gardedashealthypatientsandmay not feel comfortable operating on medically complex patients. Complex extraction cases have been linked to a higher rate of post- operative complications; therefore, acautiousandsystematicapproach should be adopted that includes a detailed preoperative assessment to predict the potential difficulties that might arise during extraction. Thedocumentationofallcomplicat- ing risk factors along with their po- tential postoperative morbidities is crucial and should be included in theinformedconsent.Inthefollow- ing article, other useful tips will be provided that are not usually in- cluded in traditional textbooks or lecture notes to help general practi- tionerstoperformsaferextractions. During clinical examination, it has been proven useful to observe the patient’s build. Tall and muscu- lar individuals tend to have a long ramus with a higher mandibular foramen,andthisincreasesthepos- sibilityoffailureoftheinferiorden- tal nerve block procedure if the for- mer is not taken into account when determining the height of the injec- tion site. This can be aided by trac- ingtheinferiordentalcanal(IDC)to the mandibular foramen in the pre- operative panoramic radiograph. The teeth of such individuals may also have longer and more curved roots and be embedded in highly dense, compact alveolar bone, and thus sectioning of the teeth may be required to ease the resistance. Racial differences should also be takenintoaccount,asextractionsof teeth from individuals of Afro- Caribbean descent tend to be more challenging owing to the hardness of their bone and divergence of roots in their molars. The resistance of hard tissue should be expected, particularly if maxillary second and third molars arebeingextracted,asthepotential for fracture of both the buccal plate andthetuberosityisrelativelycom- mon when excessive force is ap- plied with dental forceps. Fracture ofthetuberositymayproduceirreg- ularsharpbonyboundaries,signifi- cant soft-tissue laceration and po- tentiallyanoroantralfistula.Ifsuch riskfactorsareidentified,toothsec- tioningshouldbefollowedbyeleva- tion of roots with dental luxatomes instead of traditional elevators or forceps,whichareknowntodeliver much higher force to the alveolar bone. The indications for the extrac- tion of impacted lower third molars (LM3) have been the subject of long-standing debate. Surgical pro- cedures for the extraction of uneruptedLM3areassociatedwith significantmorbidity.Thisincludes pain, swelling and the possibility of temporary or permanent nerve damage, resulting in altered sensa- tion of the lip, chin, gingiva or tongue. Damage to the inferior dental nerve (IDN) is a well-known complication of surgical extraction of deeply impacted LM3. It should be acknowledged that this is not simply a loss of sensation; the dam- aged nerve can be responsible for a number of abnormal sensations, in- cluding sharp pain and abnormal responsetostimuli,suchastheper- ception of a light touch as a sharp stab. This can have a significant im- pact on quality of life for many pa- tients. InjurytotheIDNmayoccurfrom compression of the nerve, either in- directly by forces transmitted by the root and surrounding bone dur- ing elevation or directly by surgical instruments, such as elevators. The nerve may also become transected by rotary instruments or during ex- traction of a tooth whose roots are notched or perforated by the IDN. The risk factors for IDN injury dur- ing extraction of LM3 are shown in Table I. Preoperative radiographic in- vestigations may include intra- oral images, such as occlusal radi- ographs; panoramic views of the jaws; and conventional CT or CBCT scans. It should be noted that risk- predicting signs in radiographs only indicate that there is an in- creased risk of nerve damage asso- ciatedwiththeextractionofthecor- responding third molar. However, they cannot actually prevent the nerve injury if the tooth is to be ex- tracted.Theeffectivestrategiesthat mayavoidorminimisetheriskofin- jury to the IDN can be collectively categorised into two main sets. The first is the preoperative workup, which should include critical as- sessment of the need to extract the third molar, clinical examination andradiographicinvestigation,and the second is intra-operative meas- ures, including proper selection of local anaesthetic agent, the injec- tion technique, modification of the surgicalprocedureandmeasuresto reduce the degree of potential in- jury to the nerve. Most literature published in the last decade has given us sufficient evidence to suggest a significant risk of damage to both the inferior dental and the lingual nerve owing to the nerve block procedure. This injury may be related to the pharmacological properties of the agent itself or the injection tech- nique. Studies have shown that the lingual nerve is affected approxi- mately twice as often as the IDN, and one reason for this may be the fascicular pattern in the region where the injection is given. It also appears that about half of patients feel an electric shock sensation during injection. There is a higher incidence of re- portsofnerveinjuryaftertheuseof articaine and prilocaine. Although the reason for this remains un- known, it has been suggested that thismaybebecausetheyare4%so- lutions, whereas the other com- monlyusedlocalanaestheticshave lower concentrations. Others asso- ciatethedamagewiththeneurotox- icity potential of 4% articaine and 3–4%prilocaine.Hence,itisrecom- mended that the use of such anaes- thetics be limited to local infiltra- tion.Ithasbeenclaimedthatneedle contact with a nerve felt by the pa- tient as an electric shock is related to injection injury. An obvious ex- planation is that the possibility of mechanical injury to the nerve is more likely in the case of multiple repeated attempts at the inferior dental nerve block procedure. Therefore,itiscrucialthattheoper- ator achieve optimal pain control with minimal episodes of injection with minimal doses of anaesthetic agent. The surgery should be planned according to the information ob- tained from the preoperative as- sessmentprocess.Theprocedureit- self should aim to minimise the ma- nipulation around the IDC. Both should include the carefully planned access, tooth sectioning and elevation techniques. In many scenarios, the extraction of the whole tooth may carry an unavoid- Avoiding common problems in tooth extractions By Dr Kamis Gaballah, UAE Overall risk factors for IDN injury Radiographic signs of increased risk of IDN injury Full bony impactions Apices of the LM3 located inferior to the lower border of the IDC Horizontal impactions Darkening of the root Use of burs for extraction Abrupt narrowing of the root Radiographic risk markers Interruption and loss of the white line representing the IDC Clinical observation of the bundle during surgery Displacement of the IDC by the roots Excessive bleeding into the socket during surgery Abrupt narrowing of one or both of the white lines Patient’s age representing the IDC most of dentists and surgeons Table I: Risk factors for IDN injury during LM3 extraction. Educated in the UK and Ireland, Dr Kamis Gaballah is currently an associate professor and senior specialist in oral and maxillofacial surgeryattheAjmanUniversityofScienceand Technology in the United Arab Emirates. He canbecontactedatkamisomfs@yahoo.co.uk.