Tooth loss eventually occurs in most adults, and masticatory function is restored with a prosthesis such as a fixed crown & bridge, removable partial denture (RPD), or complete denture according to the extent of loss. For the RPD there are different structural-element combinations and different designs that can be applied to the same loss pattern, so that the effect and prognosis vary. Results from a statistical investigation of removable distal free-end dentures in Japan suggested that in many cases, insufficient consideration was given to mechanical stability and protection of remaining peripheral tissue in the design of removable partial dentures.
A comparison was made of autogenous grafts of rib cartilage with and without removal of the perichondrium, applied to the malar process of rats. Seventy-two male albino rats were divided into two groups according to the kind of graft received by each animal. The experimental periods were 5, 10, 20, 30, 60 and 120 postoperative days. The results showed that, in the control group, the grafts maintained their vitality for the whole experimental period and the perichondrium was biologically integrated into the host bed. Appositional growth was also observed. The treated animals showed intense resorption of the grafts and more intense bone neoformation. The newly formed bone was in intimate contact with the graft in both groups.
An in vitro study was conducted to evaluate the abrasive wear resistance of high-strength denture teeth (HS teeth). Eight types of specimen were used in the experiments; 3 types of HS teeth, 3 types of conventional plastic denture teeth (PL teeth), porcelain teeth and metal teeth. Sliding-induced wear tests were conducted by sliding the samples on a metal plate. The abrasive wear resistance of the samples was evaluated in terms of wear depth, weight loss and SEM observation. Comparison of wear depth showed that abrasive wear resistance of HS teeth was 4.7 times that of PL teeth, 0.7 times that of porcelain teeth and 8.3 times that of metal teeth. In terms of weight loss, the corresponding values were 3.3-fold, 0.2-fold and 11.4-fold, respectively.
The effect of local irrigation of the gingival sulcus, which is considered an important source of bacteremia following dental procedures, with three different antiseptic solutions including hydrogen peroxide, chlorhexidine and povidone iodine, on the frequency of bacteremia after tooth extraction was determined, and the efficacies of the three antiseptics were compared. Although all the antiseptic solutions reduced the frequency of bacteremia to various degrees, povidone iodine was the most effective, and seemed to be the best choice since the decrease was statistically significant. Local administration of antiseptic solutions is therefore recommended as an adjuvant to systemic antibiotic prophylaxis.
A histological study was conducted to evaluate the effects of fibrin adhesive material (FAM) application on periodontal healing in seven experimental dogs. Bilateral class III furcation defects were surgically created at the second and third premolars, then orthodontic wires were placed around the teeth to induce periodontitis. Six weeks later, the wires were removed and the defects were treated by either surgery alone or surgery plus FAM application. A total of 21 specimens were obtained for histological and histometrical analysis on days 7, 21 and 42. The Mann-Whitney U test showed significantly more new attachment and bone regeneration in the FAM-treated group compared to the control (p<0.05). Surgery plus FAM application in the treatment of class III furcation defects seemed to be effective in promoting connective tissue attachment and bone regeneration.
During the past 15 years, 30 patients with squamous cell carcinomas of the maxillary sinus were treated by modified partial maxillectomy following chemo-and radiotherapy, taking care to preserve facial contour and function as far as possible. Follow-up evaluation showed that local recurrences, and regional lymph node and distant metastases were more frequent in T4 patients than in T3 patients. Evaluation of the histopathological effects of preoperative chemo- and radiotherapy at the time of surgery showed that T4 patients tended to have a poorer response to the treatment than T3 patients. Analysis according to the direction of primary tumor extension showed that the incidence of local recurrence was higher in the superolateral type, whereas that of regional lymph node metastasis was higher in the medial type. The cumulative 5-year survival was high (72.2%) in Stage III patients and low (22.5%) in Stage IV patients. The overall rate was 55.4%. The treatment produced relatively good outcomes in T3 patients but poor outcomes in T4 patients. These findings indicate that T4 carcinoma of the maxillary sinus must be managed initially by a combination of irradiation and multi-chemotherapeutic drugs, and then treated by more extensive surgical resection.
Combined orthodontic-prosthodontic procedures will enhance the results of restorative treatment in adult patients. Restoration of malposed teeth using prostheses alone will fail both esthetically and functionally. Rotation, spacing or crowding and tipped teeth will compromise the final restoration if left untreated. Correction of axial inclination will prevent pulp exposure during preparation, as well as improving the periodontal status of the involved teeth. Cooperation between the orthodontist and the prosthodontist will ensure a more favorable final result. Cases treated in this manner are presented, illustrating the orthodontic treatment and the successful end results.