Dental practitioners' evaluation of the metal-resin and metal-ceramic technique in the treatment with fixed prosthetic restorations

To collect information on the use of the metal-resin and the metal-ceramic technique, a questionnaire survey among general practitioners was carried out in Bergen, Norway. Of the 20 dentists (16% sample) randomly selected among the private general practitioners, 17 (85%) responded. The results indicated that 45% metal-resin and 55% metal-ceramic constructions were inserted. Metal-ceramic crowns were selected for their favorable esthetics, whereas metal-resin appliances were preferred because of their repair possibilities and good marginal adaptation. Most dentists (70%) claimed that metal-resin restorations have a better marginal adaptation than metal-ceramic constructions. Location in the mouth, the general periodontal condition, and evidence of wear in the remaining dentition also appeared to influence the selection of the type of tooth-colored veneered crown.

Flexural strength of a high-temperature soldered cobalt-chromium alloy

The flexural strength of a high-temperature soldered cobalt-chromium alloy was compared with that of the intact alloy. In one test group the specimens were soldered by Vitallium welding rods and in the other group Bego cobalt-chromium solder was used. The cylindrical portion of all specimens was mounted equally in an Instron testing machine. No statistically significant differences were found in flexural strength between the groups.

Missing teeth and their replacement in dental school and community practice patients

This study compared tooth mortality and the pattern of prosthodontic replacement in dental patients at the University of Connecticut Dental School and patients from dental practices in the surrounding area. The dental school data were obtained from the dental records of a randomly selected 20 percent of the total patients registered during a one-year period. The dental practice data were collected through an epidemiologic monitoring system that has been established with the local dental society. The age and sex distribution of the two samples were similar. The mean number of missing teeth in dental school patients was higher (7.63 vs. 4.87), as was the proportion of edentulous persons (9.8 percent vs. 3.4 percent). The overall rate of tooth replacement in the community sample was higher than in the dental school. The proportion of fixed and removable prosthodontics was similar in the two samples (85 percent removable and 15 percent fixed). The results suggest that individuals available for the teaching of prosthodontic procedures in the dental school have many of the same intraoral conditions related to prosthodontic treatment as do patients in dental practices in the local community.

Distribution of acid-etched, fixed, and removable prostheses in dental patients

This report describes the pattern of tooth replacement for a random sample of adult dental patients in a major urban area in the northeastern United States. The data were collected by using a practitioner-based epidemiologic monitoring system that had been established with the local dental society. Nearly 90% of the randomly selected dentists collected the data on all adult patients seen during a 1-week period. The 2069 patients examined were predominantly regular users of dental care with a relatively even distribution across 10-year age groups. There was a slight preponderance of women in the sample (55%). There were no significant differences between men and women in terms of mean numbers of missing teeth. Overall, 92% were dentulous in both arches, 6% were edentulous in one arch, and 2% were totally edentulous. When the space was available for replacement, molars and premolars showed the lowest percentages of replacement in both arches for each age group. Overall, 14.4% of the replaced teeth were replaced by a fixed partial denture, of which acid-etched fixed partial dentures contributed 0.6% and conventional fixed partial dentures the remaining 13.8%. Removable prostheses replaced 85.6% of the missing teeth. The proportion of fixed replacements was highest in the youngest age groups and the proportion of removable replacements was dominating in the older age groups. Acid-etched fixed partial dentures were found most frequently in the youngest and oldest age groups.

Clinical and radiographic observations after 6 years on bridge abutment teeth carrying pinledge retainers

A group consisting of 108 bridge recipients (71 female, 37 male) with a total of 114 bridges retained solely (n = 40) by pinledges or retained by a combination (n = 74) of pinledges and complete crowns was examined clinically and radiographically 6 years after completion. The study was to review evidence of any displacement of bridges as well as the incidence of periapical changes and carious lesions of those abutment teeth fitted with pinledges (n = 210). The results showed that bridges retained solely by pinledges had become displaced more frequently than bridges retained by a combination of crowns. The failure rates (%/year) for bridges retained solely by pinledges was 2.5% and for bridges with a combination of retainers 0.25%. Three teeth (1.4%) experienced pulp exposure during the preparatory work and 6 teeth (2.8%) had been or had to be rootfilled after 6 years. Carious lesions had developed in 6 abutments (1.9%).

Alveolar bone loss in bridge recipients after six and twelve years

For a long time the major emphasis in prosthetic dentistry was placed on the technical and mechanical aspects of the different procedures and material used. The relationship between the prosthetic treatment and the periodontal tissues received less attention. As a consequence early results of epidemiological studies were not encouraging since they revealed that prosthetic treatment may be an important contributory factor in the aetiology of periodontal diseases. Research during the last two decades into the aetiology and pathogenesis of these diseases has revealed major principles and finer details relating to the mechanisms of their initiation and progression. Recent research has shown that cooperation between the prosthodontist and the periodontist, based upon agreed fundamental concepts, may give encouraging results in the prosthetic replacement of lost teeth. The study reported here assesses the effects upon the periodontal tissues of fixed bridges over a six and twelve year period.

Margin fit of metal crowns and bridge retainers

The margin fit of metal crowns and bridge retainers was examined radiographically in individuals who were registered to receive treatment at the School of Dentistry, University of Bergen. One sample consisted of 184 individuals registered in 1967-68 and another one of 232 individuals registered in 1982-83. In all, 2057 proximal surfaces could be examined. The margin fit was scored as excess, deficit, or satisfactory. In the 1967-68 single-crown sample margin excess was recorded for 66%, margin deficit for 8%, and satisfactory fit for 26%, on the average. In the 1982-83 single-crown sample margin excess was recorded for 36%, margin deficit for 5%, and satisfactory fit for 59%. In the 1967-68 sample bridge retainer margins on the average scored 60% excess, 10% deficit, and 30% satisfactory fit. In the 1982-83 bridge retainer sample margin excess amounted to 33%, margin deficit to 4%, and satisfactory fit to 63%. The possible reasons for the differences between the two samples are discussed.

Distribution of corrosion products in teeth restored with metal crowns retained by stainless steel posts

The nature and distribution of corrosion products in teeth restored with metal crowns retained by stainless steel posts were examined by means of energy-dispersive X-ray microanalysis, microradiography, and electron microscopy. The corrosion products consisted of calcium, phosphorous, iron, chromium, nickel, zinc, stannum and other elements. A possible root fracturing mechanism is discussed.