Abstract
The aim of this cross-sectional study was to examine factors associated with the eruption pattern of the second molars, and whether this pattern affects periodontal disease and dental caries of the first molars in university students.
Of 2,303 first-year students who underwent a general health examination at Okayama University in April 2013, 2,205 students volunteered to receive an oral examination. After we excluded 273 participants who were ≥20 years old and had provided incomplete data in their questionnaires, data from 1,932 students (1,124 males, 808 females), accounting for 83.9% of all first-year students, aged 18 and 19 years were analyzed. We examined their oral health status including malocclusion, total number of decayed, missing, and filled teeth, the Simplified Oral Hygiene Index, Community Periodontal Index, percentage of bleeding on probing (%BOP), and eruption pattern of the second molars. Students completed a selfreported questionnaire including items of experience of orthodontic treatment. For statistical analysis, the t-test, chi-square test, and multivariate logistic regression analysis were performed.
The percentages of participants with at least one unerupted and partially erupted second molar were 0.9 and 12.4%, respectively.
According to logistic regression analysis, the presence of abnormality on eruption of the second molars (unerupted and/or partially erupted) was significantly correlated with malocclusion (p<0.001) in both males and females. On the right side of the mandible, the percentage of BOP was significantly higher for a first molar adjacent to a partially erupted second molar. In conclusion, malocclusion was related to the eruption pattern of the second molars, and the presence of partially erupted mandibular second molars was related to the presence of BOP in the mesial first molars in the Japanese university students.
