Prevalence of the number of cusps and occlusal groove patterns of the mandibular molars in a Saudi Arabian population.

A dental trait in humans can be a valuable diagnostic tool in anthropological studies for classifying and characterizing different ethnic groups. Many studies have attempted to relate the prevalence of dental morphologies with different factors. Several variations, such as variations in the size, number of cusps, and groove pattern, have been observed in the mandibular molars of diverse populations. The morphological features of the occlusal surfaces of the mandibular molars have been described by Gregory and Hellman. To date, no studies have been reported in the literature regarding the frequency and expression of different types of cusps and the occlusal groove patterns in a Saudi Arabian population. The present study aimed to determine the prevalence of different occlusal morphologies (number of cusps and occlusal groove patterns) of the permanent mandibular first and second molar in a Saudi population and to correlate its importance in forensics, if any. The results of this study showed that the most frequent occlusal configurations were the 5-cusp pattern seen in 85% (136 teeth) and the 4-cusp pattern seen in 11% (18 teeth) of the mandibular first molars, bilaterally. Regarding the mandibular second molars, the 4-cusp form was the most common occlusal configuration, seen in 82% (132 teeth), followed by the 5-cusps type, seen in approximately 16% (26 teeth), bilaterally. Statistically significant (P value = 0.001) differences were noted for the permanent mandibular first and second molars between male and female subjects in all cusp and groove patterns ("Y" and "+" patterns). Similarly, significant differences (P value = 0.001) were found between the unilateral and bilateral presence of different cusp and groove patterns, both in the mandibular first and second molars. The present study showed that the groove pattern in the mandibular first molars was very different when compared to other populations. The cusp and groove patterns of the mandibular second molars were similar to those of the East African and Iranian populations. The results of this study may be used in forensics. Thus, the outcomes of this study may be helpful in both anthropological and clinical dental research.