Abstract: PURPOSE: The purpose of this cone-beam CT (CBCT) based study was to investigate the stages of palatal suture at different age groups as well as the bone density of the palatal suture in a south Chinese population. METHODS: The CBCT data of 113 patients with an age range from 4 to 36 years old were selected. All of them were reported to have normal growth. CBCT image data were selected in accordance with the inclusion criteria. By using Angelieri method, the palate was divided into 5 groups, and Chad Evans Larson bone density ratio was calculated for each patient. One-way ANOVA and LSD analysis were used to evaluate the average bone density ratio of the mid-palatal at each age stage as well as the mean value of palatal suture bone density at different stages with SPSS 22.0 software package. RESULTS: By comparing the density ratio of mid-palatal suture for each age group, no significant difference was noticed for the same stage regardless of the age (stage B, C and D) (P>0.05), significant difference was noticed between C and D(P<0.05),no significant difference was noticed for the suture density between group A and B as well as group C and D (P>0.05), significant difference was found for the suture density between A/C, A/D, A/E, B/C, B/D, B/E, C/D, and C/E groups(P<0.05). CONCLUSIONS: The mid-palatal suture density in children under 15 years may belong to stage A, B or C , which is significantly lower than group D and E; Patients of a palatal stage C stay within an age range from 11 to 18. No inner group difference is noticed inside group C. The average suture density of group C is significantly larger than group A and B, whereas smaller than group D and E. The results showed that CBCT can be a useful tool to guide rapid mid-palatal expansion in clinical practice. Patients who have a lower density mid-palatal suture can be expanded.

Key words: Sage of the palatal suture, Density of the palatal suture, Palatal expansion