Reverse-sequencing chewing patterns before and after treatment of children with a unilateral posterior crossbite

Abstract

The aim of this study was to compare the percentage of reverse-sequencing chewing cycles in 22 children [9 boys and 13 girls; mean age +/- SD, 8.6 +/- 1.3 and 8.8 +/- 1.5 years, respectively), with a unilateral right or left posterior crossbite, before and after therapy. The chewing cycles were recorded using a kinesiograph while the subjects masticated a soft and a hard bolus on both the crossbite and non-crossbite side. Chewing data were acquired before and 6 months after orthodontic treatment of the crossbite with an orthodontic functional appliance, the 'Function Generating Bite'. The results showed that, before therapy, the percentage of reverse-sequencing chewing cycles on the crossbite side was significantly higher than that on the normal side (P < 0.001) with both the soft and hard bolus. In addition, the percentage of reverse-sequencing chewing cycles on the crossbite side before therapy was significantly greater than after therapy with both a soft and hard bolus (P < 0.001). No significant differences were found in the percentage of reverse-sequencing chewing cycles on the non-crossbite side, before or after therapy, either with a soft or hard bolus.

Expression of muscle-specific integrins in masseter muscle fibers during malocclusion disease

“…Our previous report, evaluating the muscular activation during chewing in unilateral posterior crossbite patients, showed that the kinematics and electromyography characteristics of the masseters of the non-affected side were similar to those of controls, whereas the masseters of the crossbite side were less active (34) meaning that patients with unilateral posterior crossbite show a serious functional asymmetry during chewing (33).…”

“…The masseter of the crossbite side is less active than the counterpart, and the co-ordination of the masticatory muscles on the two sides is altered with respect to controls (33,34).…”

“…Subjects with unilateral posterior crossbite exhibit different kinematics of the mandible during mastication when chewing on the affected side, resulting in an increased frequency of reverse chewing cycles (32,33). The masseter of the crossbite side is less active than the counterpart, and the co-ordination of the masticatory muscles on the two sides is altered with respect to controls (33,34).…”

Slow or rapid palatal expansion for early treatment of unilateral posterior crossbite? Evaluation of the reverse chewing cycles correction

“…It is intriguing to hypothesize that when opposing occlusal contacts occur, the central nervous system directly receives refined peripheral inputs from periodontal, muscular, oral receptors and a strict motor control of the mandibular movement, with very little freedom, is established to avoid the occlusal contacts 21,25 .…”

“…Reverse chewing cycles are characterized by altered muscular activation corresponding to altered kinematics and altered pattern morphology 24 . They occur on the crossbite side only, being the chewing cycles on the non-affected side normal; this is the reason why a unilateral posterior crossbite is characterized by dental and functional asymmetries 25 .…”