The Assessment of the Prevalence of Impacted Third Molars, Its Relation to Space Available for Eruption, and Its Effect on the Adjacent Second Molar in Adults From 18 to 65 Years of Age Using Orthopantomograms: A Retrospective Cross-Sectional Study.

Introduction Third molar impaction surgeries are part of the most common minor oral surgeries performed by maxillofacial surgeons. In spite of being part of the everyday evaluation, the importance of preoperative planning and intraoperative and postoperative complications cannot be overlooked. This study aims to evaluate the prevalence, patterns, available eruption space, and impact of third molar impaction on the adjacent second molar in an adult population. Methods A retrospective observational cross-sectional study was conducted over a total of 380 panoramic radiographs from patients aged 18-65 years, which was analyzed to assess the incidence, angulation, and space available for the eruption of impacted third molars and their effects on the adjacent second molars. Orthopantomograms (OPGs) from January 2023 to December 2023 were included in the study. A total of 1280 third molars from 380 OPGs were studied encompassing an extensive range of demographics. Results The results showed that 54.7% (208/380) of the studied population had at least one impacted third molar, with a higher prevalence in the mandibular arch. Vertical impaction was the most common pattern (224/419, 53.46%), followed by mesioangular (92/419, 21.95%), horizontal (85/419, 20.28%), and distoangular (18/419, 4.29%) impactions. Notably, the study found a relevant association between impacted third molars and the development of distal caries in the adjacent second molar (76/419, 18.13%). These findings highlight the importance of early radiographic evaluation of impacted third molars to prevent potential damage to adjacent teeth and inform clinical decisions regarding the management of such cases. The study also highlights that there is a significant amount of third molar impaction seen in women (211/380, 55.52%) compared to men, and the age group range with the highest incidence of third molar impaction is 18-25 years (399/1280, 31.20%). Additionally, a significant number of mandibular impacted third molars present with some level of nerve involvement, whereas more than 80% of maxillary impacted third molars showed sinus approximation. This study also presents a novel concept of "eruption space ratio," which is the ratioof the mesiodistal width of the crown of the third molar to the space available posterior to the second molar for eruption. When it was compared to the angulation, a substantial link was seen, although none was seen in relation to the level of impaction. Conclusion This study underlines the need for proactive dental care in populations with a high prevalence of third molar impaction, aiming to mitigate the risks to the adjacent second molars and to eliminate possible postoperative complications through timely intervention.