ORIGINAL RESEARCH article
Front. Oral Health
Sec. Oral Epidemiology
The association between maximum mouth opening and sociodemographic factors among Saudi adults: a cross-sectional study
Provisionally accepted
Bayan Almohaimeed1*
Rashad Ikram2- 1Department of Community Dentistry and Oral Epidemiology, College of Dentistry, Qassim University, Qassim, Saudi Arabia
- 2Department of Oral and Maxillofacial Surgery, Buraidah Central Hospital, Qassim Health Cluster, Qassim, Saudi Arabia
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Maximum mouth opening (MMO) is an essential clinical measurement for evaluating mandibular function and temporomandibular joint mobility. Establishing normative values across populations is crucial for the accurate diagnosis of trismus and for guiding oral and maxillofacial interventions. This study aimed to determine the mean MMO among Saudi adults and to examine its association with sociodemographic and anthropometric variables. A cross-sectional study was conducted among 400 adults in Qassim, Saudi Arabia. MMO was measured using a digital caliper with triplicate readings averaged for analysis. Sociodemographic and anthropometric data were recorded. Group differences in MMO were assessed using one-way analysis of variance (ANOVA), followed by Tukey post hoc testing for variables with statistically significant ANOVA results, in addition to Monte Carlo-adjusted chi-square tests for categorical comparisons. A multivariable linear regression model was performed to identify independent predictors of MMO. The mean of MMO was 45.7 ± 6.9 mm (median: 46.3 mm; range: 28.0-66.3 mm). ANOVA showed significant differences in MMO by gender (p < 0.0001) and height (p < 0.0001), with males and taller individuals exhibiting greater mouth opening. No significant differences were found across age, weight, or BMI categories. In the multivariable regression model, height remained the only significant independent predictor of MMO (β = 0.154, p = 0.008), while gender showed a non-significant trend. Age and weight were not associated with MMO. In this adult Saudi population, MMO was primarily influenced by height, with males showing larger values. Age, weight, and BMI were not significant predictors. These findings support using sex and stature-adjusted reference values to improve trismus diagnosis and clinical decision-making. Further research incorporating craniofacial measures is recommended to refine normative standards.
Keywords: Mandibularmobility3, Maximum mouth opening (MMO)1, Oral health assessment6, sociodemographic factors2, Temporomandibular joint (TMJ)5, Trismus4
Received: 14 Oct 2025; Accepted: 15 Dec 2025.
Copyright: © 2025 Almohaimeed and Ikram. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Bayan Almohaimeed
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