Objective: To determine the maximum mouth opening (MMO) in Pakistani adult population and its possible correlation with sex and age.

Design of the Study: It was a cross-sectional study.

Study Settings: This study was carried out at Outpatient Department of Dentistry Combined Military Hospital, Lahore from January 2019 to July 2019.

Material and Methods: The study involved 894 adults’ patients having 463 males and 431 females patients age in the range of twenty one year to seventy years. The patients were asked maximally open their mouth and keep it open until no further opening of mouth possible. Then with the help of calibrated fiber ruler distance was measured from incisal edge of the upper incisor teeth to the incisal edge of the lower incisor teeth. To check the correlation of mouth opening with age a Pearson correlation analysis was done and significance of the test was checked by applying the independent sample T-test will be applied taking p value of ≤0.05 as statistically significant. A written informed consent was obtained from every patient.

Results of the Study: For males mean maximum opening of mouth was observed as 51.4±8.1 mm having its range 38 to 70. Mean maximum opening of mouth for females was observed as 43.1±5.9 mm having age range 37 to 55 mm. In 21 to 30 years age group the opening of mouth was 39.90 ± 5.02 mm for female’s patients and 40.26 ± 5.26 mm for male patients. In 31 to 40 years age group the opening of mouth was 39.54 ± 4.69 mm for females and for female’s patients it was 40.24 ± 4.55 for male patients. In 41 to 50 years age group MMO was 40.24 ± 5.02 mm for females and was 40.97 ± 4.79 mm for males. In age 51 to 60 years age group the equivalent values for males were 41.54 ± 5.49 and for females41.04 ± 5.63 mm. In 61 to 70 years age group the corresponding values for females and males were 40.33 ±5.55 mm and41.25 ± 6.04 respectively.

Conclusion: The mean MMO for males was 51.4 ± 8.2 and for females was 43.1 ± 6.7. The opening of the mouth looks to reduce with age. The opening of mouth of females is not as much of the males in the all groups of age.

Keywords: Maximum mouth opening (MMO), Age, Sex