Vertical Occlusal Dimension Research Articles

垂直的顎位と体位がえん下機能に及ぼす影響

垂直的顎位と体位がえん下機能に及ぼす影響

Processing Changes in Complete Dentures Constructed from Pour Resins

In this study, the dimensional changes that occur during processing of complete dentures constructed from two acrylic pour resins were determined. No significant differences were observed between the two products tested. It was found that the average amount of linear dimensional shrinkage that occurred would be undetectable clinically; however, considerable contraction occurred while the processed dentures were stored in distilled water. There was minimal decrease in the vertical occlusal dimension of individual dentures. However, the loss in both upper and lower dentures, combined with selective grinding to perfect the occlusion, will reduce the vertical occlusal height and some overclosure can result unless this loss is compensated for. The clinical significance of the loss is discussed as are future objectives for study of pour technique denture base materials. In this study, the dimensional changes that occur during processing of complete dentures constructed from two acrylic pour resins were determined. No significant differences were observed between the two products tested. It was found that the average amount of linear dimensional shrinkage that occurred would be undetectable clinically; however, considerable contraction occurred while the processed dentures were stored in distilled water. There was minimal decrease in the vertical occlusal dimension of individual dentures. However, the loss in both upper and lower dentures, combined with selective grinding to perfect the occlusion, will reduce the vertical occlusal height and some overclosure can result unless this loss is compensated for. The clinical significance of the loss is discussed as are future objectives for study of pour technique denture base materials.

Dento-Facial Deformities

The aim of this study was to explore the relationship between dental wear and facial morphology, with particular reference to the occlusal vertical dimension, in modern human skulls.One hundred and three skulls (52 men and 51 women) between the ages of 20 and 50+ years old were studied. The selected skulls were from a modern period (the 17th and the 18th centuries) and included at least one entire condyle and had at least 3 posterior teeth (premolar or molar) in each quadrant to allow for dental articulation. Occlusal wear was evaluated using ordinal scale (0–4) and vertical occlusal dimension was evaluated by measuring upper facial height (UFH), lower facial height (LFH), LFH-to-UFH ratio (L-U-R) and dental wear. Based on the occlusal wear score, two groups were defined: with and without significant wear.Significant relation was observed between age and dental wear (P < 0.01). No significant differences were found in the LFH (P = 0.847) or UFH (P = 0.108) between the two wear groups. In addition, no significant difference (P = 0.132) was demonstrated in the LFH-to-UFH ratio between the groups. No difference was observed in the dental wear score between genders (P = 0.321).Within its limitations, this study demonstrated that dental wear does not influence the vertical dimension of occlusion. Our assumption is that the dento-facial complex fully compensates for the dental effects of wear throughout life.