[Characteristics of occlusal force and contact in 20 individual normal occlusion children with mixed dentition].

Abstract

Objective: To measure and analyze the occlusal force and contact in children with mixed dentition, and to preliminarily provide baseline data on the occlusion of individual normal occlusion children with mixed dentition.

Methods: A cross-sectional study was conducted, including 20 children with mixed dentition and individual normal occlusion, consisting of 12 boys and 8 girls, aged 6.5-9.8 years. The Dental Prescale Ⅱ occlusal analysis system was used to measure the occlusal force and contact at the intercuspal position, including the maximum occlusal force (N) and the occlusal contact area (mm²) of the entire dentition, and the left and right sides, average occlusal pressure (MPa), maximum occlusal pressure (MPa), and to determine the position of the center of occlusal force. The gender differences in maximum occlusal force, average occlusal pressure, and occlusal contact area were analyzed, the bilateral symmetry of occlusion in children with mixed dentition and individual normal occlusion was compared, and the correlation between occlusal data and age, height, weight, and body mass index (BMI) was analyzed.

Results: (1) The average maximum occlusal force of the entire dentition in the 20 children with mixed dentition at the intercuspal position was (869.18±106.64) N, the average occlusal contact area was (25.19±2.89) mm², the average occlusal pressure was (34.37±5.98) MPa, and the maximum occlusal pressure M(P₂₅, P₇₅) was 120 (120, 120) MPa; (2) There was no statistically significant difference in the maximum occlusal force, average occlusal pressure, maximum occlusal pressure, and occlusal contact area between the left and right sides (P>0.05); (3) At the intercuspal position, the average occlusal contact area for 12 boys and 8 girls was (26.71±3.91) mm² and (21.62±3.08) mm² respectively, and the average maximum occlusal force was (911.92±145.05) N and (769.47±116.45) N respectively, with statistically significant differences (P < 0.05), while there was no statistically significant difference in the average occlusal pressure between boys and girls (P>0.05); (4) The maximum occlusal force at the intercuspal position was weakly correlated with age (r=0.219, P=0.046), and strongly positively correlated with the occlusal contact area (r=0.949, P < 0.001), while the average occlusal pressure, maximum occlusal pressure, and occlusal contact area were not correlated with age, height, weight, or BMI; (5) The center of occlusal force in the 20 children with mixed dentition and individual normal occlusion was located in the molar region, with 7 children having the maximum occlusal pressure point only in the first permanent molar region, 10 children having it in both the deciduous molar region and the first permanent molar region, and 3 children having it only in the deciduous molar region.

Conclusion: In children with mixed dentition and individual normal occlusion, the maximum occlusal force, occlusal contact area, average occlusal pressure, and maximum occlusal pressure at the intercuspal position show good bilateral symmetry; there are gender differences in the maximum occlusal force and occlusal contact area, with boys having greater values than girls; the maximum occlusal force is positively correlated with the occlusal contact area.