ROEN0310

38 I I case report _ retreatment _Root-canal retreatment is a predictable treat- ment modality. When patients were informed about this treatment option in the past, the dentist often over-emphasised the possibility of failure. This still occurs today, however more and more practitioners are realising that root-canal retreatment can be a hugely successful treatment modality and can save the patients natural teeth while still maintaining prostheticreplacementoptionsforthefutureshould it become necessary. In our private practice, approxi- mately 50 per cent of referred cases are endodontic retreatments and, using modern state-of-the-art techniques, success rates from 70 to 95 per cent are possible, which is in line with recently published out- come studies.1 Priortoinitiatinganycomplextreatment,theover- all dentition is examined. The position of the tooth in the mouth, its functional and aesthetic requirements, theperiodontalconditionandtheamountofremain- ing tooth structure are critical parameters to assess. Adiscussionofthetreatmentoptionshasbecome more complex over the years, as patients demand more detailed information about prospective treat- ments.Additionally,thenumberoftreatmentoptions hasincreased.Atoothwithpreviousroot-canaltreat- ment that has failed may be monitored, extracted, re-root-canal treated, either surgically or non-surgi- cally or occasionally an intentional re-implantation may be preformed. In an ideal world, a cost-benefit analysis of each possible treatment should be dis- cussed with the patient. This is a challenging discus- sion as the number of variables both known and unknown are significant. Whenassessingatoothforthepossibilityofroot- canal retreatment, I try to establish the source of infection.Failureisalmostexclusivelyduetothepres- ence of bacteria. In the majority of cases, the bacteria will be located within the root-canal system. On rare occasions, there will be an extra-radicular infection. Bacteria such as Actinomyces species have been shown to be able to survive in resorbed regions of the external root surface. A practitioner is unable to distinguish, however, whether the bacteria are extra- or intra-radicular. Non-microbial causes of failure include presence of cysts, foreign body reactions and possibly the presence of scar tissue rather than healing with bone andconnectivetissue.Inthepast,50percentofperi- apical radiolucencies were believed to be cysts.2 Our current understanding, however, suggests that the incidenceoftruecystsisaroundsixpercent.3 Another possible cause of failure is a foreign-body reaction to materials such as talc powder from gutta-percha points, but this is unlikely to be a common cause of failure.Finally,largelesionsthatextendandperforate thebonycortexbuccallyandlinguallycansometimes heal with scar tissue and be misdiagnosed as not healed radiographically. Thecriticalquestiononemustaskbeforeinitiating treatment is: Can I reach the area of infection and eliminate sufficient bacteria to create conditions conductive to health/healing? The most likely com- mon cause of failure is missed canals that have a bacterial biofilm extending to the apical foramen. Remember,themesio-buccalrootofmaxillarymolars has two canals around 95 per cent of the time. Mag- nification,adequatelightandknowledgeofwhereto Fig. 1_Pre-op radiograph. roots3_2010 Root-canal retreatment: To treat or not to treat? Author_ Dr Daniel Flynn, UK Fig. 1

Please activate JavaScript!
Please install Adobe Flash Player, click here for download