Masticatory performance in Mexican children with and without deep-bite malocclusion

It is important to recognize if malocclusion causes functional limitations besides originating esthetic problems. Deep-bite is a frequent component of malocclusion that can be found in young children. Objectives: The objective of this cross-sectional study was to compare masticatory performance in Mexican children with and without deep-bite malocclusion. Methods: Masticatory performance was evaluated in 5 to 7 year old boys and girls with (n=68) and without (n=34) deep-bite (>50%). Masticatory performance was evaluated following a standardized protocol using CuttersilŪ as a test food. Each child chewed the test food for two sequences; till swallowing threshold first and next for 20 cycles. The chewed particles were dried and sifted through seven sieves. Median particle size (MPS) and broadness of particle distribution (BPD) were determined using the cumulative weights on each sieve and the Rosin-Rammler equation. Results: No statistical significant differences were found between groups. MPS after 20 cycles was 3.19 mm. and 3.16 mm. for the with and without deep-bite groups respectively. BPD at 20 cycles was 3.45 for the deep bite group and 3.88 for the group without deep-bite. MPS was only 13% smaller at swallowing threshold than after 20 cycles although the average number of chews till swallowing threshold was 35. Statistical differences were found between cycle duration when chewing till swallowing threshold or for 20 cycles (0.703 vs 0.637 msec, p=.000). Children chewed 11% slower when they chewed till swallowing threshold than when they chewed 20 times. Only 2.9% and 2.2% of the test food was lost when chewed till swallowing threshold or 20 cycles respectively. Conclusion: Our data does not endorse differences in masticatory performance between Mexican 5-7 year old children with and without deep-bite malocclusion.