Kosar Gharehkhan, Reza Faraji, Valiollah Arash, Hemmat Gholinia,
Volume 39, Issue 0 (3-2026)
Abstract
Background and Aims: Bolton ratios—the anterior and overall ratios—are important indicators for assessing the dental proportionality between the maxilla and mandible, playing a crucial role in achieving ideal occlusion and successful orthodontic outcomes. Given individual variations in facial growth patterns and their potential influence on these ratios, the present study aimed to evaluate the relationship between Bolton ratios and vertical skeletal patterns in the population from northern Iran, as well as to investigate the effect of gender on these ratios.
Materials and Methods: In this observational-analytical study, 173 Class I orthodontic patients
(121 females and 52 males) with a mean age of 16.02 ± 4.51 years were evaluated. Based on the vertical facial pattern using the Jarabak index, the subjects were categorized into three groups: short face (n=52), normal face (n=67), and long face (n=54). The anterior and overall Bolton ratios, and overbite were measured from dental casts. Data were analyzed using Chi-square, ANOVA, t-test, and Pearson’s correlation coefficient in SPSS ver. 26, with a significance level set at 0.05.
Results: No statistically significant differences were found in the anterior and overall Bolton ratios among the three vertical facial groups (P=0.062 and P=0.36, respectively) or between genders (P=0.53 and P=0.42, respectively). In contrast, the mean overbite significantly differed among the groups (P<0.001). Comparison of the anterior (79.16 ± 3.88%) and overall (90.09 ± 6.89%) Bolton ratios with the original Bolton standards revealed statistically significant differences (P=0.001 and P=0.02, respectively).
Conclusion: According to the findings, neither the vertical skeletal pattern nor gender had a significant effect on Bolton ratios. Nevertheless, the observed differences between the ratios in this northern Iranian population and the original Bolton standards underscore the importance of using population-specific norms in orthodontic treatment planning.
