RANGE OF MOUTH OPENING AMONG THREE MAJOR ETHNIC GROUPS IN NIGERIA

BACKGROUND: Maximum mouth opening (MMO) is an important parameter in the assessment of several clinical situations and its measured value is documented to have racial, gender, age and anthropometric variation. OBJECTIVE: To determine the maximal mouth opening and its predictors among the different major ethnic groups in Nigeria. METHODS: Study subjects were 449 adults (232 males, 215 females), age range 18-74 years from the three major ethnic groups in Nigeria. MMO measurements and anthropometric parameters were recorded. Data analysis was done using SPSS Version 22 and variables subjected to univariate analysis to determine association and a linear regression model was performed to determine variables that could predict maximum mouth opening with p-value set at < 0.05. RESULTS: The overall mean MMO across the ethnic groups was 49.33 ± 7.91mm. Mean MMO for the Yoruba ethnic group, 53.06 ± 6.27 mm was found to be significantly higher than values obtained for Hausa tribe 52.77 ± 8.06 mm and Igbo tribe 47.59 ± 8.61 mm (p=<0.001). Age, weight and height were observed to correlate significantly with MMO. A multivariate linear regression model revealed that age and height were independent predictors of maximum mouth opening across the ethnic groups. CONCLUSION: There is ethnic variation in MMO among the 3 major ethnic groups in Nigeria with mean MMO values of 53.96 (± 6.27 mm), 52.77 (± 8.06 mm) and 47.59 (± 8.61 mm) for the Yoruba, Hausa and Igbo ethnic groups respectively. Age and height are important predictors of MMO.