Cephalometric evaluation of the changes in mandibular symphysis after 7 years of denture wearing.

OBJECTIVE: To evaluate changes in mandibular symphysis during 7 years of complete denture wearing following extraction of natural anterior teeth. DESIGN: Comparison among measurements taken at four different occasions in a prospective cephalometric study. SETTING: The study was conducted at the Dental School of Athens University. SUBJECTS: 10 complete denture wearers (5 women, 5 men) with average age of 53.2 years, at the beginning of the study. MEASURES: Linear and area measurements of the mandibular symphysis. RESULTS: The overall reduction in the anterior mandibular height was 7.87 mm and in the mandibular symphysis area 54.8 mm2 (p < 0.05). Females presented higher total average reduction in both variables tested, and more rapid bone loss during the first two years of denture wear, compared to men. Superimposition of the tracings revealed considerable individual variation in mandibular symphysis changes. CONCLUSION: Results are in line with the findings of other authors indicating continuous reduction and dramatic inter-subject variation in the mandibular alveolar bone, following extraction of natural teeth and wearing of complete dentures.

Changes in mandibular alveolar bone and anterior face height after four years of complete denture wearing.

A 4-year cephalometric study was conducted on 14 wearers of complete dentures to quantify the anterior alveolar bone loss and to study any associated changes in the maxillomandibular relationships. Both the occlusal and the rest-face heights underwent a significant decrease while a parallel tendency for anterior rotation was recorded. The continuous bone loss in the anterior mandible had a significant relationship to the reduction of the anterior face height.

Changes in the mandibular rest position after removal of remaining teeth and insertion of complete dentures.

A 24-month study was conducted to determine changes in the mandibular rest position after removal of the remaining teeth and insertion of complete dentures. A total of 24 patients with at least 10 teeth acting as occlusal stops were included in this study. Serial lateral cephalometric radiographs were made for each patient on four occasions (1) before extraction (2) 7 to 10 days after the initial denture insertion (3) 12 months later, and (4) 24 months later. Two angular measurements and one linear measurement were made for each radiograph and compared. A statistically significant increase in the face rest height with a tendency for posterior mandibular rotation was recorded between stages 1 and 2. This initial posterior rotation was followed by a gradual forward and upward movement, which finally brought the mandibular rest position even below the preextraction levels. The findings confirm the concept of the variability of posture and suggest that the mandibular rest position is an unreliable means of reestablishing the vertical dimension of occlusion that existed before extraction of the natural teeth.