Neurosensory deficit is a well-reported complication after lower third molar surgery. It is useful to know the outcomes of the available treatments for neurosensory deficit after third molar surgery. It is more important to prevent nerve injury from third molar surgery. This thesis aims1) to evaluate the outcomes of treatments for neurosensory deficit after lower third molar surgery; 2) to investigate the effect of permanent neurosensory deficit from the patient’s perspective;3) to identify radiographic signs as predictors of inferior alveolar nerve (IAN) deficit in third molar surgery; 4)to monitor the long-term root movement and morbidities of the retained roots following coronectomy of the lower third molars. (1) A systematic search on treatment modalities and their outcomes of neurosensory deficit after lower third molar surgery was performed. 4 surgical treatments and 2 non-surgical treatments were identified. Significant improvement in sensation was found in the majority of the subjects who received surgical or non-surgical treatment. Complete recovery was uncommon in all kinds of available treatments. (2) Forty-eight subjects (24 cases) were recruited in a prospective case-control study comparing the general and oral health-related quality of life (QoL), life satisfaction and depression symptoms of patients with persistent lingual nerve (LN)or IAN neurosensory deficit (12 months or more) after third molar surgery with those who did not have such deficit. It was found that patients with persistent neurosensory deficit after third molar surgery have significantly poorer general and oral health-related QoL, worse life satisfaction and more depression symptoms than those without such deficits. (3) Twelve patients with neurosensory deficit after lower third molar surgery (10 LN, 2 IAN) who received microsurgical repair of the affected nervewere recruited in a prospective longitudinal observational study of the treatmentoutcomes. Most patients with pain wererecovered after surgery. Subjective symptoms including numbness, taste sensation and speech were improved after LN repair. Improvement was noted in all three objective neurosensory tests at post-operative 12 months. (3) Twelve patients with neurosensory deficit after lower third molar surgery (10 LN, 2 IAN) who received microsurgical repair of the affected nervewere recruited in a prospective longitudinal observational study of the treatment outcomes. Most patients with pain were recovered after surgery. Subjective symptoms including numbness, taste sensation and speech were improved after LN repair. Improvement was noted in all three objective neurosensory tests at post-operative 12 months. (4) 178lower third molars with one or more of the five radiographic signs suggesting of close proximity of their roots to the IAN were analyzed. It was found that radiographic signs of “darkening of root(s)” and “displacement of inferior alveolar canal by the root(s)” were associated with increased risk of intraoperative IAN exposure. In addition, “darkening of the root(s)” or co-existing radiographic signs were associated with an increased risk of post-operative IAN deficit. (5) A phase 4 clinical trial with 612 lower third molar coronectomies was conducted to monitor the long term safety of the treatment. It was demonstrated that the technique has minimal morbidity in terms of infection, pain, dry socket or development of pathologies. Most retained roots (90.9%) migrated upward with the highest migration rate in the first 6 months, which gradually slowed down and stopped to migrate at 24months. 2.3% of the roots became exposed in the oral cavity and required removal. Re-operation to remove the exposed root did not cause any IAN deficit. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

Background Various analgesics are available for post-operative pain after third molar surgery. Combinations of different classes of analgesics may improve the overall efficacy of pain control as they covers different pain pathways. A great variation of combinations and dosages of analgesics have been suggested in the literature, yet it was still unclear what combination(s) and dosages were the most effective for acute post-operative dental pain. A systematic review of randomized clinical trials would help clinicians to make clinical judgment of which analgesic combination(s) would be the best for their patients for acute post-operative dental pain in terms of efficacy and safety. Aim To conduct a systematic review of randomized clinical trials to answer the clinical question “which analgesic combination and dosage is potentially the most effective and safe for acute post-operative dental pain control?” Methods A structured systematic literature search, with predefined inclusion and exclusion criteria, of the relevant computer databases and journals was performed. The search and the evaluations of articles were done by 2 independent reviewers in 3 rounds. Studies that fulfilled the pre-set criteria were included to enter the final review. The analgesic efficacy of the analgesic combinations reported in the included studies were presented by the objective pain measurements, sum of pain intensity at 6 hours (SPID6) and total pain relief at 6 hours (TOTPAR6). The SPID6 and TOTPAR6 of various combinations were adjusted after deducting from the effect of placebos of the respective studies. The adverse effects of the different analgesic combinations were also presented. Results There were 13 studies with 2843 subjects included in the final review. Eight groups of drug combinations with 13 different dosages were reported. The efficacies of the reported analgesic combinations have SPID6 scores ranged from 1.46 to 6.44 and TOTPAR6 scores ranged from 3.24 – 10.3. Among the analgesic combinations, ibuprofen 400mg + oxycodone HCL 5mg had the highest adjusted SPID6 (6.44), and a very higher adjusted TOTPAR6 (9.31), representing its efficacy could be superior to the other different analgesic combinations reported in this study. Nausea was the most common adverse effect of the analgesic combinations, with prevalence ranged from 0-55%. Most of the common adverse effects were related to the use of opioids in the combination. Three combinations of different dosages containing ibuprofen and caffeine were reported with the lowest prevalence of adverse effect. Conclusions This systematic review of randomized clinical trials has presented the efficacy and adverse effects of the various analgesic combinations for acute post-operative dental pain control. We have identified ibuprofen 400mg with oxycodone 5mg was more effective when compared to the other 12 combinations. Nausea was the most common adverse effects in an analgesic combination containing an opioid. Ibuprofen 200mg with caffeine 100mg or 200mg has a reasonable analgesic effect with fewer side effects when compared to the other analgesic combinations. / published_or_final_version / Dental Surgery / Master / Master of Dental Surgery