Asbjørn Jokstad

Assessment of the periapical and clinical status of crowned teeth over 25 years

OBJECTIVES The purpose of this study was to examine radiographically changes in the periapical status and compare the clinical status of teeth with a vital pulp and root-filled teeth restored with crowns and bridge retainers during 25 years. METHODS During 1967/68, 114 patients received prosthodontic treatment by senior dental students at the Oslo Dental Faculty. In all, 291 teeth with a vital pulp and 106 root-filled teeth were restored with 158 prostheses. All root-filled teeth were restored with a cast dowel and core. The casts were made in a type-3 gold alloy, and cemented with zinc phosphate cement. Forty-six teeth were restored with crowns and 351 teeth with bridge retainers. Radiographs were taken preoperatively, immediately after cementation, and every fifth year. Two independent observers assessed the periapical status on the radiographs according to the PAI-index. At the 25 years examination, 32 patients (28%) with 101 restored teeth (24%) remained in the study. Survival rates of the prostheses and of the restored teeth were estimated using Kaplan-Meyer non-parametric statistics. RESULTS The PAI-score of the periapical status deteriorated in 13 vital and four root-filled teeth. The survival rates of the fixed prostheses were not influenced by the pulp vitality of the restored tooth at the baseline. The survival rates of the restored teeth with a vital pulp and of the root-filled teeth were similar. Clinical failures were recorded on approximately one-third of the restored teeth. The main reason for tooth failure was caries (12%), and for the teeth with a vital pulp also pulpal deterioration (10%). Estimates of the proportions of crowned teeth with a vital pulp that will remain free from signs and symptoms of pulpal deterioration were 98% after five years, 92% after 10 years, 87% after 20 years and 83% after 25 years. CONCLUSIONS The incidence of periapical lesions on radiographs of crowned teeth was low during 25 years observation. Crowned, root-filled teeth with a high quality endodontic treatment and an optimal morphology of the dowel and core have a similar survival rate as crowned teeth with a vital pulp. A high proportion of crowned teeth with a vital pulp will remain free from signs and symptoms of pulpal deterioration over 25 years.

The age of restorations in situ

In a cross-sectional survey the age of restorations in situ was recorded in three patient groups. Group A were randomly examined regular attenders, group B were irregular attenders randomly chosen from patient treatment records, and in group C the age of posterior gold and composite resin restorations was recorded in selected regular attenders. The study material included 8310 restorations in group A, 1281 in group B, and 500 restorations in group C. The three materials amalgam, composite, and gold accounted for more than 90% of all restorations. In group A 3.3% of the restorations were scheduled for replacement. The most prevalent reasons for replacement were secondary caries, bulk fractures of the restoration, and tooth fractures. The median age of the failed restorations was fairly similar to the median age of the acceptable restorations in situ among the regular patients (group A). The data indicate median ages of 20 years for gold restorations, 12-14 years for amalgam restorations, and 7-8 years for composite resin restorations. The restoration ages were influenced by the type and size of the restoration, the restorative material used, and possibly also the intra-oral location of the restorations.

Five-year study of Class II restorations in permanent teeth using amalgam, glass polyalkenoate (ionomer) cermet and resin-based composite materials

Abstract The aim of this study was to compare the clinical performance of an amalgam, a glass polyalkenoate (ionomer) cermet material and a resin-based composite material used in small Class II cavities in permanent teeth. All restorations were inserted under rubber dam. They were examined yearly for 3 years. One clinician continued the study up to 5 years. The clinical examination focused on two criteria: clinically acceptable and failure. In addition, impressions were taken of the prepared cavities immediately before restoration and at each clinical examination using an elastomeric material. The study comprised 274 Class II restorations (88 amalgams, 95 cermets and 91 resin composites) placed in 142 adolescent patients. One hundred and sixty-seven restorations were in molar and 107 in premolar teeth. Patient dropout after 5 years resulted in the loss of 161 restorations, evenly distributed for restorative material and type of tooth involved. Four amalgam restorations, 22 glass ionomer cermet and nine resin composite restorations failed. The glass ionomer cermet and amalgam restorations failed primarily due to bulk fractures, while the resin composite restorations failed due to secondary caries and bulk fractures.

ORAL HEALTH IN INSTITUTIONALIZED ELDERLY PEOPLE IN 1993 COMPARED WITH IN 1980

The dental and periodontal status, oral hygiene, and dental visit habits of 250 residents in long-term care (LTC) facilities for the elderly in a suburban community in Norway were recorded. The findings were compared with the data from an identical examination of the residents in the same LTC facilities in 1980. In 1993 the mean number of remaining teeth per person was 11.7 (CI = 10.3-13.1). The mean number of filled teeth was 5.1 (CI = 4.1-6.0), and the mean number of decayed teeth was 1.8 (CI = 1.4-2.2). The mean number of residual roots per person was 0.8 (CI = 0.5-1.1). Periodontal pockets exceeding 4 mm was recorded on 5% of all teeth. In general, the oral hygiene was poor. Edentulousness had decreased from 80% in 1980 to 54% in 1993, and more remaining and filled teeth and fewer residual roots per person were observed in the 1993 population. The findings show that the objective need for resources to prevent periodontal disease and caries among elderly patients in LTC facilities today is higher than previously.

Ten years' clinical evaluation of three luting cements

OBJECTIVE The aim of the present clinical longitudinal study was to observe, over 10 years, the prognosis of abutment teeth restored with fixed prostheses retained by glass ionomer luting cements and one conventional zinc phosphate cement. METHODS Three dentists prepared 135 abutment teeth in 61 patients to retain 81 fixed prostheses. The prostheses were retained by two glass ionomer luting cements (Ketac-Cem, Fuji Ionomer), or a conventional zinc phosphate cement (De Trey Zinc Zement Improved). The patients were examined yearly for 10 years. RESULTS Post-operative hypersensitivity occurred in five teeth restored with glass ionomer luting cement. The prevailing reason for abutment tooth failure was secondary caries (n = 21) and pulp necrosis (n = 5). Non-parametric survival estimates indicated that 80-85% of the abutment teeth remained intact after 5 years and 71-81% after 10 years. CONCLUSIONS The 10-year results indicate that the prognosis of abutment teeth restored with fixed prostheses is good, regardless of whether a glass ionomer or a zinc phosphate luting cement is used.

Clinical trial of gingival retraction cords.

STATEMENT OF PROBLEM A wide spectrum of different gingival retraction cords is used, while the relative clinical efficacy of these cords remains undocumented. PURPOSE This study aimed to determine whether clinicians were able to identify differences in clinical performance among 3 types of gingival retraction cords. METHODS AND MATERIAL Dental students and faculty members ranked pairs or series of cords according to 6 criteria for clinical performance, with a blind experimental study design. Cords differed in consistency (knitted or twined) and impregnation (8% dl-epinephrine HCl, 0.5 mg/in or 25% aluminum sulfate, 0.5 mg/in). RESULTS Knitted cords were ranked better than twined cords (P =.03). Cords containing epinephrine performed no better clinically than aluminum sulfate cords (P >.05). CONCLUSION Clinicians were unable to detect any clinical advantages of using epinephrine impregnated gingival retraction cords compared with aluminum sulfate cords.

Osseointegration and dental implants

Osseointegration and dental implants / , Osseointegration and dental implants / , کتابخانه دیجیتال جندی شاپور اهواز

Replacement reasons and service time of class-II amalgam restorations in relation to cavity design

Four hundred and sixty-eight class-II amalgam restorations were placed in 210 patients. The restorations had been inserted by seven Scandinavian dentists in their clinics, among their regularly attending patients. Impressions of the teeth with cavity preparations had been made, and epoxy casts fabricated. The designs and qualities of the cavities were assessed in accordance with an evaluation system for class-II cavities designed for use on models. The restorations were observed yearly and scored in accordance with the USPHS criteria. In case of replacement the reason was recorded, and the service time calculated. The restorations were observed throughout a period varying from 8 to 10 years. At the end of the observation period, 212 restorations had been lost owing to dropout patients, 68 restorations had been replaced, and 188 restorations remained functional. The commonest criteria for replacement were secondary caries (n = 30) and restoration bulk fractures (n = 24). Using univariate statistics and multivariate discriminant analyses, the time of service and the reasons for replacement were correlated with different clinical variables, including different indices for the dimensions and qualities of the cavity preparation. Several features of the cavity design could be associated with the service time of the restoration or with the reason for replacement, or both. Secondary caries was primarily associated with cavity design features gingivally on the proximal surface (p less than 0.001). At the patient level the rate of secondary caries correlated with the total number of restorations placed during the observation period, irrespective of the quality of the cavosurface margins or the size of the cavity. Restoration bulk fractures could be related to cavities with narrow and deep occlusal parts, or deep proximal parts (p less than 0.001). The discriminant functions predicted correctly between 70% and 93% of the actually failed restorations in the failure groups. The good prediction performance indicates that a linear discriminant analysis that includes aspects of the prepared cavity may be applied to predict the reasons for failure of restorations.

Dental implant suprastructures using cobalt–chromium alloy compared with gold alloy framework veneered with ceramic or acrylic resin: a retrospective cohort study up to 18 years

BACKGROUND An association between the long-term success and survival of implant-supported prostheses as a function of biomaterial combinations has not been established. The use of cast cobalt-chromium for the suprastructure framework may be an alternative to the conventional approach of using type 3 gold alloys. MATERIALS AND METHODS A retrospective chart audit of all patients who had received implant-supported fixed dental prostheses (FDP) before 1996 was identified in a private practice clinic. Data were recorded for FDPs made from four combinations of alloy frameworks and veneering material, i.e. type 3 gold and cobalt-chromium with ceramic or prefabricated acrylic teeth. The extracted data from the charts were subjected to explorative statistical tests including Kaplan-Meier survival analyses. RESULTS Patients (n=198) with 270 short and extensive FDPs supported entirely by 1117 implants were identified. The average follow-up observation periods varied between 4 and 220 months, with an average of 120 months. The success and survival, as well as event rates and types of biological and technical complications, were similar for implant-supported FDPs using cobalt-chromium and type 3 gold alloy frameworks veneered with ceramics or prefabricated acrylic teeth. An influence of the suprastructure biomaterial combination on the clinical performance of the individual supporting implants could not be established. CONCLUSIONS Implant-supported FDPs made from type 3 gold or cobalt-chromium frameworks and veneered with ceramic or prefabricated acrylic teeth demonstrate comparable clinical performance. The biomaterial combinations do not appear to influence the success or survival of the individual implants.

Wear of teeth due to occupational exposure to airborne olivine dust

Objectives. To clarify whether high tooth wear of employees in a mining industry that extracts the mineral olivine could be associated with airborne dust exposure in their working environment. Method. The cumulative exposure to airborne mineral dust for the workers in the company was calculated on the basis of their period of employment multiplied by the airborne olivine-dust concentrations, which have been monitored continuously during the past 20 years for all divisions of the company. After invitation, 85% of the employees (n=191) were examined clinically and their dentitions were photographed and duplicated in plaster casts. Four clinicians, working independently, examined the sets of casts/photographs for tooth wear and ranked these from most to least. Two groups of employees were compared with regard to tooth wear, i.e. the 30% with the highest (case) and the lowest (control) estimated dust exposure levels. Tooth wear in the case and control groups was compared using a non-parametric test based on rankings (Mann-Whitney test). Results. Tooth wear differed significantly between the workers in the low and the high mineral dust exposure groups (p<0.001). The differences were also apparent within three age subsets, although statistical significance was reached only in the 34–44 years subset (p=0.002). Considerable individual variation was noted within the three exposure groups. Conclusion. Workers with high exposure to airborne olivine dust may contract considerable tooth wear.