Occlusal Surface Analysis of Mandibular Premolars in Koreans

Yoo, Hong Il; Park, Ha Yeon; Kim, Sun Hun

Abstract

The aim of this study was to investigate the characteristics of mandibular premolars regarding size and morphology in Koreans. Moreover, comparisons of gender difference in mandibular premolars were examined to expand anatomical database in Koreans. Data was obtained from students in School of Dentistry, Chonnam National University, Gwangju, Korea. The total number of participants was 66 (33 men and 33 women) and dental casts were fabricated. A total of nine items was investigated using a digital measuring software. Five measurements were performed including intercuspal distance (ID), buccolingual diameter (BL), mesiodistal diameter (MD), total crown area, and each cusp area. One item as each cusp area ratio was calculated, and three items were observed including the number of lingual cusp, occlusal groove patterns, and mesiolingual developmental groove. Comparison measurements were analyzed using paired t-tests, independent t-tests and Pearson correlation tests. Average values in mandibular second premolars were larger than first premolars in most of measurements with a significance with the exception of mesiodistal diameter (p=0.223). Overall average values were significantly higher in male than in female except intercuspal distance (p=0.607) and lingual cusp area (p=0.070) in mandibular premolars. The presence of mesiolingual developmental grooves in the first premolars was 59.1% (male 51.5%, female 66.7%). The most common occlusal groove patterns of the second premolar were a Y pattern, followed in order by H and U patterns. These results provide valuable morphological characteristics of mandibular premolars in Koreans.