A structural equation model to investigate the impact of missing occlusal units on objective masticatory function in patients with shortened dental arches.
ABSTRACT The aim of this study was to investigate the impact of missing occlusal units (MOUs) on objective masticatory function with respect to food comminuting and mixing ability. Sixty partially dentate patients (mean age, 64·1 years) with shortened dental arches participated in the study. Food comminuting ability was assessed using a masticatory performance test with peanuts as a test food. Food mixing ability was assessed using a mixing ability test with a two-coloured wax cube. Maximum bite force (MBF) was measured using a pressure-sensitive film as a mediator for food comminuting and mixing ability. A structural equation model was constructed based on a hypothesis that MOUs would be associated with reduced MBF and impairment of food comminuting and mixing ability. Structural equation modelling analysis found significant direct effects of MOU on median particle size and mixing ability index (MAI) (P < 0·001). In addition, MOU had significant indirect effects on median particle size and MAI with MBF as a mediator (P < 0·05). These results suggest that decrease in occlusal platform area and reduced MBF because of MOUs are associated with the impairment of food comminution and mixing in patients with shortened dental arches.
- International Journal Odontostomatology. 08/2012;
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ABSTRACT: It is well known that shortened dental arch decreases masticatory function. However, its potential to change brain activity during mastication is unknown. The present study investigates the effect of a shortened posterior dental arch with mandibular removable partial dentures (RPDs) on brain activity during gum chewing. Eleven subjects with missing mandibular molars (mean age, 66·1 years) on both sides received experimental RPDs with interchangeable artificial molars in a crossover trial design. Brain activity during gum chewing with RPDs containing (full dental arch) and lacking artificial molars (shortened dental arch) was measured using functional magnetic resonance imaging. Additionally, masticatory function was evaluated for each dental arch type. Food comminuting and mixing ability and the perceived chewing ability were significantly lower in subjects with a shortened dental arch than those with a full dental arch (P < 0·05). Brain activation during gum chewing with the full dental arch occurred in the middle frontal gyrus, primary sensorimotor cortex extending to the pre-central gyrus, supplementary motor area, putamen, insula and cerebellum. However, middle frontal gyrus activation was not observed during gum chewing with the shortened dental arch. These results suggest that shortened dental arch affects human brain activity in the middle frontal gyrus during gum chewing, and the decreased middle frontal gyrus activation may be associated with decreased masticatory function.Journal of Oral Rehabilitation 04/2014; · 2.34 Impact Factor
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ABSTRACT: Purpose The purpose of this study was to clarify whether there might be a gender difference in masticatory movement path and rhythm in dentate adults. Methods Thirty healthy males and 30 healthy females were asked to chew softened chewing gum on their habitual chewing side for 20 sec, and the movement of the mandibular incisal point was recorded using mandibular kinesiograph. For 10 cycles from the fifth cycle, the spatial and temporal parameters (spatial: amounts of vertical and lateral movements; temporal: opening, closing, occluding, and cycle times) of masticatory movement path and rhythm and the parameters representing the stability of masticatory movement path and rhythm were calculated and compared between males and females. Results The values of the spatial parameters were significantly greater for males than for females. The values of the temporal parameters were smaller for males than for females, and significant differences were found in all parameters except occluding time. However, there was no statistically significant difference in the parameters representing the stability of masticatory movement path and rhythm. Conclusion From these results it was suggested that although there were no differences in the stability of masticatory movement path and rhythm between genders, there were gender differences in the spatial and temporal parameters of masticatory movement path and rhythm.Journal of Prosthodontic Research 01/2014;