[Specifics of mastication with complete dentures].

INTRODUCTION

Mastication is a process characterized by alternating phases of physiological inactivity, food intake, initial food crumbling, mouthful formation and deglutition. Although there is a so called human type of mastication, this process is individual for variety of reasons. Mastication is not an innate characteristic and it must be learned, but once it is learned, it gets a reflexive function, demanding maximal involvement of the highest nervous system centers.

DISCUSSION

Specificities of mastication in complete denture wearers are caused by specificities connected to changes of the oral cavity due to teeth loss, technical features of complete dentures and quality of their manufacture. Loss of teeth causes loss of periodontal receptors consequently damaging the source of information which, as long as teeth are present, travels from the oral cavity towards the central nervous system and regulates the masticatory muscles activity. As one of the consequences of periodontal receptors' loss, interocclusal perception decreases, because the number of receptors within the masticatory mucosa is negligible. Another problem is that loss of teeth causes loss of the occlusal surface. Occlusal surface is considered to be the only reference coordinate of the zero intermaxillary separation with precise spatial representation within the someostatic field cortex. Permanent loss of antagonistic contact causes disappearance of the memory pattern of the occlusal surface. Therefore completely edentulous mouths are characterized by disintegration of the free interocclusal space. Masticatory forces' value directly depends on the: size of muscles creating the forces, their position in the mandibula, shape of the edentulous alveolar ridge, type of chewing, the relationship between the height of the branch, length of the mandibular body, gonial angle, mandibular angle in relation to the anterior cranial base and posterior facial height and the degree of intermaxillary separation. Bite forces in complete denture wearers are significantly decreased in relation to persons with natural teeth. There is a fundamental difference in the distribution of the functional energy in complete denture wearers and subjects with intact teeth. Persons with natural teeth tend to generate energy through bolus, whereas in complete denture wearers most of the chewing energy is distributed outside bolus, directly through the denture base on the supporting tissues.

RESULTS

As the result of this specific dynamics stress of supporting tissues often occurs with consequential mucosal inflammation and rapid alveolar bone resorption. Reduction of masticatory efficacy in denture wearers may be caused by irregular activity of masticatory musculature or is the consequence of irregular flow of energy during mastication. In comparison with young examinees with healthy teeth, authors have registered that complete denture wearers need about seven times more masticatory movements to achieve equal number of sample parts.

CONCLUSION

It has been documented by experience and also scientifically proved, that the satisfaction of complete denture wearers is not often proportional with objective functional denture values. Comparison of subjective parameters with objective test results reveals that the percentage of complete denture wearers who consider their dentures to be good, although they objectively are not such, is significantly higher than the percentage of those who complain about their dentures, although they are functionally proper. Our study comprised patients (average age of 69) who wore complete dentures longer than five years.