Aims To evaluate the clinical characteristics of mandibular third molar teeth (Md3M) requiring removal and to compare the characteristics of impacted Md3M with non-impacted Md3M. Methods One thousand and eleven patients who had 1,431 Md3M removed were evaluated. Features recorded included the age and gender of patients, the primary diagnosis indicating removal, the angulation and impaction status of the Md3M. Results The most common indications for Md3M removal were pericoronitis (49%), caries and related disease (C&RD) (27%), and distal cervical caries (DCC) of the mandibular second molar tooth (Md2M) (14%). The mean age of patients requiring removal of Md3M was 32.4 years. The mean age of patients, based on the angulation of impaction, were 28.6 years for vertical impaction, 30.1 years for mesio-angular impaction, 29.6 years for disto-angular impaction, 31.7 years for horizontal impacted and 41.6 years for non-impacted Md3M. The mean age of patients, based on the most common diseases were, 27.5 years for pericoronitis, 32.7 years for Md2M DCC, 36.1 years for C&RD, and 46.3 years for periodontal disease. Forty-one percent of all patients have Md3M removed due to disease related to dental caries with Md2M DCC accounting for 44% of all mesio-angular impacted Md3M removed. Conclusion Third molar disease varies according to the type of Md3M impaction. Impacted Md3M succumb to disease earlier than non-impacted Md3M. Pericoronitis remains the most common indication for impacted Md3M removal, however, C&RD and Md2M DCC have become more prevalent and are seen in older population groups. Md2M DCC is predominantly seen related to impacted mesio-angular third molars. Non-impacted Md3M, when indicated for removal, are generally removed in older patients due to C&RD and periodontal disease. The authors conclude that impacted third molars are more likely to be removed in younger patients due to pericoronitis while caries related disease (C&RD and Md2M DCC) is more common in older patient groups. With Md2M DCC accounting for 44% of all mesio-angular impacted Md3M being removed, consideration should be given to early intervention in the management of patients with mesio-angular impacted teeth.