Prevalence of disease associated with horizontal and mesioangular-impacted mandibular third molars in relation to age

Background The management of impacted mandibular third molars (M3Ms) has been an area of contention over the last 25 years. This study investigated the prevalence of disease processes in relation to age for a sample of patients with horizontal and mesioangular M3Ms.Method All concomitant disease processes including probing pocket depths (PPDs) and alveolar bone loss (ABL) distal to mandibular second molars (M2Ms) were recorded from a sample of 400 patients.Results From 536 M3M/M2M interfaces, 41% (n = 219) had a disease process present on the distal surface of the M2M and 11% (n = 61) had such significant disease that the M2M was removed. Presence of M3M caries was 38.2% (n = 205); localised periodontitis, 21.5% (n = 115); pericoronitis, 20.1% (n = 108); and M2M caries, 18.5% (n = 99). No simple correlation between age and number of disease processes was found (r = -0.020; p = 0.648); although, the prevalence of M2M caries and pericoronitis was related to age (χ² = 9.951; p = 0.007 and χ² = 12.834; p = 0.002), as was PPD and ABL (p <0.001).Conclusion(s) Multiple disease processes can occur concomitantly with horizontal or mesioangular M3Ms. Discussion of disease risk with regular clinical and intra-oral radiographic monitoring by general dental practitioners is recommended.