Maximal Mouth Opening Index among Dental Students in Khartoum University

This study aimed to determine the maximum mouth opening [MMO] among a group of Sudanese adults. Reduced mouth opening [MO] can lead to difficulties in mastication and social interactions, potentially impacting dental treatment planning. Comparing the MMO values between males and females, relating each subject’s 3-4 finger width to inter-incisal distance was the method used.

A total of 277 undergraduate students [179 females and 98 males], aged 18–25 years, participated in the study. MMO was measured as the vertical inter-incisal distance using a digital vernier caliper. Participants were also assessed on the number of fingers they could fit vertically between their incisors, with the normal range defined as 3–4 fingers. The finger width in millimeters was then compared to the previously measured MMO. Additionally, the ratio between MMO and maximum lateral mandibular movements [right and left excursions] was recorded.

The overall mean MMO was 52.64 ± 6.4 mm, with males exhibiting a significantly higher mean MMO [56.33 ± 6.77 mm] compared to females [50.62 ± 5.19 mm]. Approximately 69.3% [n=192] of participants could place four fingers vertically between their incisors. A statistically significant difference was found when comparing the mean MMO to the finger width measurements [p < 0.001]. The mean lateral excursion was 9.13 mm, and a significant correlation between MMO and lateral excursion was observed, with a ratio of approximately 1:5.6

The mean MMO was 52.6 mm, higher than most previous studies, possibly due to ethnic and physical differences. Males showed greater MMO than females, likely due to larger mandibular size, although females may have relatively greater joint mobility. Most subjects could insert four fingers vertically between their incisors, unlike other populations, reflecting higher MMO in this group. Lateral mandibular movement averaged 9.13 mm, consistent with other studies, and a weak positive correlation was found between vertical and lateral mouth movements, especially in males.

The mean MMO in this Sudanese adult population was 52.64 mm, with males demonstrating significantly greater mouth opening than females. Most participants [69.3%] could accommodate four fingers inter-incisally. The ratio of MMO to lateral excursion was higher than previously reported in the literature, suggesting potential population-specific variations.