Factors predictive of difficulty of mandibular third molar surgery

Aim Historically the difficulty of third molar surgery has been judged usin g radiologically assessed dental factors specifically tooth morphology and position. This study investigated additional factors that have a bearing on the difficulty of extraction. Study design A prospective study undertaken by three clinical assistant gra de surgeons who removed 354 single mandibular third molar teeth under day c ase anaesthesia over the 4-year period (1994-1998), Method Data relating to patient, dental and surgical variables were collect ed contemporaneously as the patients were treated. The difficulty of extrac tion was estimated by the surgeons pre-operatively using dental radiographi c features and compared by the same surgeon within the actual surgical diff iculty encountered at surgery. Operation time strongly related to both pre and post treatment assessments of difficulty and proved to be the best meas ure of surgical difficulty. Results Univariate analysis identified increased patient age, ethnic backgr ound, male gender, increased weight, bone impaction, horizontal angulation, depth of application, unfavourable root formation, proximity to inferior a lveolar canal and surgeon as factors increasing operative time. Multivariat e analysis showed that increasing age (P = 0.014), patient weight (P = 0.02 4), ethnicity (P = 0.019), application depth (P = 0.001), bone impaction (p = 0.008) and unfavourable root formation (P = 0.009) were independent pred ictors for difficulty of extraction. Conclusions Half of the six independen t factors that predicted surgical difficulty of third molar extraction were patient variables.