Panoramic Radiographic Analysis of Distal Caries Prevalence in Mandibular Second Molars Associated with Adjacent Third Molar Position: A Retrospective Study in Benghazi, Libya

Abstract

The present study aimed to investigate, using panoramic radiographs, the association between mandibular third molars and the occurrence of distal caries in adjacent second molars. This retrospective cross-sectional study was conducted at Elaml Dental Centre, Benghazi, Libya, using digital panoramic radiographs (orthopantomograms, OPGs) obtained between January 2022 and November 2023. A total of 557 radiographs from Libyan adults aged over 21 years were examined to evaluate the eruption status and angulation of impacted mandibular third molars, as well as the presence of distal caries in adjacent mandibular second molars. Impaction patterns were classified according to Winters’ and Pell & Gregory's systems. Statistical analysis was performed using the Chi-square test. Results showed that 339 second molars (34.8%) exhibited caries on the distal surface. The majority of second molars affected by distal carious lesions were linked to Level A third molar status, comprising 194 affected mandibular second molars (57.2%), followed by Level B, which accounted for 133 cases (39.2%). Mesially inclined third molars were most commonly associated with distal caries in the second molars (n=144, 42.5%), followed by vertically oriented third molars (n=94, 27.7%). The study concluded that mandibular third molars are associated with an increased risk of distal caries in second molars, especially when they are classified as level A or mesioangular-tilted third molars. It is advisable to conduct regular radiographic examinations for early detection. Additionally, if impacted third molars are in contact with the oral cavity, their removal may be necessary as a preventive measure.