Biomedical subjects

A Jokstad

Publications and source records attributed to A Jokstad.

At least 37 records · Page 2Linked to original sources

PubMed1996

Relationships between risk factors and treatment outcome in a group of patients with temporomandibular disorders.

The aim of this study was to compare somatic complaints, anxiety, and pain related to temporomandibular disorders (TMD) in a group of TMD patients who had high scores for headache and muscle palpation compared with that of a group of TMD patients who had low or medium scores for headache and palpation before and 2 years after conservative TMD treatment, consisting of counseling, muscle exercises, and a stabilization splint. The high-score group consisted of 23 patients who had headaches several times a week or daily and had more than three muscles graded as severely tender to palpation. The low/medium-score group comprised 28 patients who had headaches hardly ever, once or twice a month, or several times a month, and with muscles graded as slightly or medium tender to palpation. The patients answered three questionnaires (McGill Pain Questionnaire [Norwegian version], a somatic complaints questionnaire, and the trait part of Spielberger Stait-Trait Anxiety Inventory) before and 2 years after treatment. The findings showed differences between the two groups concerning pain description, general muscle complaints, and anxiety both before and after the treatment, with the high-score group showing the highest values. In general, the treatment outcome had improved in the low/medium-score group but remained unchanged in the high-score group.

Adult↗

PubMed1996

The reporting of pain, somatic complaints, and anxiety in a group of patients with TMD before and 2 years after treatment: sex differences.

The aim of this study was to assess possible gender differences regarding the reporting of pain, somatic complaints, and anxiety in a group of patients suffering from temporomandibular disorders (TMD). The group consisted of 40 females and 13 males who received conservative TMD treatment comprising counseling, muscle exercises, and a stabilization splint. Before and 2 years after treatment, the patients answered three questionnaires (McGill Pain Questionnaire [Norwegian version] including a six-point scale, the Present Pain Intensity; a Somatic Complaints Questionnaire; and the trait part of Spielberger's State-Trait Anxiety Inventory. Before treatment, females reported greater present pain intensity than did males. Two years after treatment, females reported less sensory and emotional pain than at the initial stage; males presented no reduction in these pain scores. There were no gender differences at either stage regarding somatic complaints or anxiety level scores.

Adult↗

PubMed1994

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.

Composite Resins↗

PubMed1994

Clinical performance of three anterior restorative materials over 10 years.

The long-term performance of two chemically activated composite resins was compared to that of one silicate cement. Bulk and cavosurface marginal discoloration was evaluated with both an indirect photographic method and the direct US Public Health Service evaluation system. The results confirmed that composite resins had superior performance but higher secondary caries incidence than did silicate cements. The macrofilled composite resins showed better clinical performance than the microfilled restorations, as well as similar incidences of bulk and marginal discoloration. The agreement between the scores obtained with the direct evaluation criteria and those resulting from the indirect evaluation method was relatively poor. The indirect scores were usually the same or poorer than the direct clinical scores. The results indicated that the clinical evaluation may be the least sensitive of the two methods. The discrepancy in the scorings may, on the other hand, signify that the indirect photographic method records reflectance spectra that are not normally obtained in vivo.

Adolescent↗

PubMed1993

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

The aim of this study was to compare the clinical performance of an amalgam, a glass polyalkenoate (ionomer) cerment 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 cerments 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 cerment and nine resin composite restorations failed. The glass ionomer cerment and amalgam restorations failed primarily due to bulk fractures, while the resin composite restorations failed due to secondary caries and bulk fractures.

Analysis of Variance↗

PubMed1993

Oral hygiene, periodontal conditions and carious lesions in patients treated with dental bridges. A 15-year clinical and radiographic follow-up study.

A longitudinal study, extending over a period of 15 years, was carried out in a group of 102 patients who received 108 bridges made by the senior students at the Dental Faculty, University of Oslo, in 1967/68. The study included 343 abutment teeth, and the remaining teeth in the same jaw which received the restoration, 525 in all, served as control. The oral hygiene, gingival condition, pocket depth, caries on crowned teeth, location of crown margins and changes of alveolar bone level were recorded during the study. During the first 10 years, the patients received oral hygiene prophylaxis every 6 months. The mean age of the patients at the beginning of the study was 48 years. Of the original group of 102 patients, 88 attended the clinical examination after 5 years, 71 after 10 years, and 55 after 15 years. The amount of plaque did not differ between the crowned teeth and the control teeth during the observation period, while GI score 2 and 3 was more frequent in crowned teeth than in the control teeth during this period. This was mainly observed when the crown margins were located sub-gingivally. A slight increase in mean pocket depth was recorded in the crowned teeth while the mean pocket depth for the control teeth remained at the same level during the 15 years. Caries lesions were recorded in 3.3% of the abutment tooth surfaces at the 5th year, in 10.0% at the 10th year and in 12.0% at the 15th year examination. No statistical differences in bone loss could be detected between the control teeth and the crowned teeth.

Adult↗

PubMed1992

Dental amalgam and mercury.

The mercury concentrations in blood (HgB) and urine (HgU) samples, and in exhaled air (HgAir) were measured in 147 individuals from an urban Norwegian population, using cold vapour atomic absorption spectrometry. The study aimed to estimate the mercury exposure from the dental restorations, by correlating the data to the presence of amalgam restorations. Mean values were HgB = 24.8 nmol/l, HgU = 17.5 nmol/l and HgAir = 0.8 micrograms/m3. HgU correlated with HgAir, and both HgU and HgAir with the number of amalgam restorations, amalgam restored surfaces and amalgam restored occlusal surfaces. HgB showed poor correlation to HgU and HgAir and the presence of amalgam restorations. A differentiation of the mercury absorption due to exposure from dental amalgams and from the dietary intake, necessitates measurements of both organic and inorganic mercury in the plasma, and in the erythrocytes. The results suggest that individuals with many amalgam restorations, i.e., more than 36 restored surfaces, absorb 10-12 micrograms Hg/day.

Adolescent↗

PubMed1991

Influence of cavity depth on marginal degradation of amalgam restorations.

In a 5-year clinical trial it was observed that the marginal degradation of class-II amalgam restorations could be related to the bulk of the restoration. The association between the occlusal cavity depth and the marginal degradation was observed after 6 months and varied for the different types of alloy. Ridit scores of the marginal degradation were correlated to various indices of the cavity sizes, to assess the possible reason for this association. The possibilities of the relationship being an indirect effect caused by longer condensation times or by poorer condensation due to the use of larger condenser sizes were rejected. Furthermore, the possibility that the association was the result of potential buildup of stresses on the restoration margins caused by flexible cusps and axial walls was not apparent. A possible mechanism may be that marginal degradation is the result of short-term or long-term expansion, or even extrusion of amalgam. Expansion may theoretically be caused over short periods by temperature changes or over long periods by corrosion or phase shifts in the amalgam. The theory does not exclude the role of creep or corrosion and may furthermore explain the lack of correlation between in-vitro tests and in-vivo performance of amalgam restorations.

Dental Alloys↗

PubMed1991

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 Alloys↗

PubMed1991

Assessment of marginal degradation of restorations on impressions.

The study aimed to validate the scoring of the degree of marginal degradation of amalgam restorations by using impressions, as an alternative to other indirect scoring methods using photographs or casts. Ten-year-old condensation silicone elastomer impressions and epoxy replicas made in 1979 were compared in a scanning electron microscope at 5 kV with different magnifications up to x200. The impression material was not distorted or degraded, and the dimensional stability was good after 10 years of storage in a dry environment. The inter-examiner agreement of the scorings of impressions and a six-point scale reference set was satisfactory as evaluated by kappa statistics, demonstrating that degrees of marginal degradation can be distinguished on impressions with relatively high accuracy. The rating distribution of the scorings of impressions showed good correlation to the rating distributions obtained with the clinical USPHS rating method and with photographs for recording marginal degradation. A slight difference between the photographic and impression ratings at the upper and lower levels of the six-point rating scale was observed. The difference varied with the type of alloy, possibly due to a bias depending on the surface quality--that is, whether the restoration kept the glossiness of high polishing or became heavily tarnished.

Dental Alloys↗

PubMed1991

Analyses of long-term clinical behavior of class-II amalgam restorations.

The purpose of the study was to estimate the influence of different clinical variables on the replacement rate of class-II amalgam restorations in permanent teeth. The study included 210 patients who had 468 restorations placed by 7 Scandinavian dentists. The observation periods varied between 7 and 10 years. At the time of the last recording 188 restorations remained intact in 88 patients, whereas 68 restorations in 53 patients had been replaced. Eighty-six patients with 212 restorations had dropped out of the study. The most prevalent criteria for replacement were secondary caries (n = 30) and restoration bulk fractures (n = 24). Chi-square analyses of the relationship between the prevalence of replacements and the clinical variables indicated effects of the operator and the patients' age and caries activity (p less than 0.001). Similar results were observed when the functional time of the restorations was related to the clinical variables and analyzed by ANOVA and MCA analyses and by survival analyses using logrank and Wilcoxon tests (p less than 0.001). The survival analyses using the Lee-Desu statistic D showed in addition a slight difference between the restorations in the lower premolars and upper and lower molars. There were no differences in the clinical performance between four non-gamma-2 alloys and one conventional alloy. Furthermore, no differences were noted between the survival rates of MC, DO, and MOD restorations. In a Cox regression model the strongest effects on the estimated survival rates were associated with the patients' age and caries activity covariates (global chi-square = 23.5, df = 2, p less than 0.001), whereas the effects of the operator and the other clinical variables were insignificant.

Adolescent↗

PubMed1990

Mercury excretion and occupational exposure of dental personnel.

At the annual congresses of the Norwegian Dental Association in 1986 and 1987 surveys were conducted to assess the significance of potential sources of mercury exposure. Morning urine samples and questionnaires were collected from 672 participants in 1986 and 273 participants in 1987. The mean values of the urinary mercury excretion were 39 nmol/L (SD = 29) in 1986, and 43 nmol/L (SD = 36) in 1987. The excretion values were correlated to the answers on questionnaires supplied from each participant. The data was analyzed using ANOVA, multiple classification analyses, and Pearson correlation. The correlations between environment and practice characteristics and the mercury excretion values reconfirm in general results from previous investigations. In addition, the data indicate that urinary mercury excretion may be gender dependent and that the restorative status of the participants contribute to the daily mercury exposure. Moreover, the excretion correlates not only to the number of placed restorations per week, but also to the number of polished and replaced amalgam restorations per week. Participants working in environments with wooden floors had significantly higher mean mercury values than other dental personnel. Elevated mercury values were also observed for participants working in clinics with installed amalgam separators or other filtering devices. The possibility that the storage of collected scrap amalgam and mercury from the filtering devices increases the mercury vapor in the work environment warrants further investigation.

Adult↗

PubMed1990

Clinical variables affecting the marginal degradation of amalgam restorations.

The influence of different clinical variables on the marginal degradation of amalgam restorations was studied in a clinical trial of class-II amalgam restorations. Seven Scandinavian dentists using 5 different alloys placed 468 restorations in 210 patients. The marginal degradation was scored on impressions of the restored teeth by using a six-point ordinal rating scale and was transformed to ridit values. After 5 years 126 patients with 296 restorations remained in the trial. Ridit analysis and paired comparison tests utilizing the Bonferroni correction factor at each yearly interval indicated that the extent of degradation of the restoration margins was influenced by the location in the mouth, the position on the tooth, the type of alloy, and the operator. The results demonstrate that features of the cavity preparation and the handling of the material by the operator are more important for the degradation of the restoration margins than other clinical variables.

Adolescent↗

PubMed1990

Cavity design and marginal degradation of the occlusal part of Class-II amalgam restorations.

The effect of variations in the design of class-II cavity preparations on the marginal degradation of amalgam restorations was included as a study aim in a clinical trial. Four hundred and sixty-eight restorations were placed in 210 patients by 7 Scandinavian dentists using 5 different alloys. The marginal degradation was scored on impressions of the restored teeth by means of a six-point ordinal rating scale. The scores were then compared with defined characteristics of the occlusal parts of the initial cavity preparations. Characteristics of the cavity that could be related to the marginal degradation were diverging occlusal cavity walls, occlusal cavity depth, fissures perpendicular to the cavosurface angle, and rough or variable occlusal cavosurface angles. Cavity preparation features not influencing the rate of degradation were the occlusal width, the location of the cavosurface angle on the cusp slope, occlusal cavosurface angles with sectors smaller than 90 degrees, and less than 1 mm enamel remaining between the cavity preparation and another restoration. The association between the different cavity design features and the marginal degradation varied with the different alloys. Superior marginal performance is probably the result of optimal condensation or surface treatment, rather than features of the cavity preparation.

Dental Alloys↗

PubMed1990

Longevity of posterior restorations.

The efficacy of restorative dentistry is dependent on a number of factors, including material quality, operator proficiency and the oral hygiene of the patient. The sum effect of all factors can be measured by recording the longevity of the restorations. Many studies focus on the age of restorations at the time of failure, others include the longevity of restorations which remain in situ. The surveys may be either longitudinal, prospective or retrospective, or cross-sectional retrospective studies of dental records. They are all hampered by the lack of uniform criteria defining when to place and replace restorations and by variations in decision-making between clinicians. The present review paper shows that the longevity of amalgam restorations has been studied most frequently. About 50 per cent of all amalgam restorations exceed 8-10 years in age, cast gold restorations may last longer and multisurfaced composite restorations have a shorter life-span. Glass ionomer cements lack the physical properties needed for large posterior restorations. The results of detailed longevity studies should be the basis for selection of materials and techniques in operative/conservative treatment. The cost of dental treatment should be related to the expected lifetime of the tooth rather than to the immediate cost of a simple restoration.

Bicuspid↗

PubMed1989

The quality of routine class II cavity preparations for amalgam.

In spite of many improvements in operative dentistry, the incidence of replacements of amalgam restorations remains high. It is possible that specific cavity features are important for the longevity of the restorations. Six hundred and ten epoxy plastic models, made from impressions of permanent teeth in which class II cavities had been prepared by eight Scandinavian dentists, were examined. The examination showed prevalent imperfect external and internal cavity features. These may reflect the operators' opinion of adequate operative dentistry, neglect to control design features, or lack of training in examining a cavity critically.

Dental Amalgam↗

PubMed1989

The dimensions of everyday class-II cavity preparations for amalgam.

Six hundred and ten epoxy plastic models, made from impressions of permanent teeth in which class-II cavity preparations for amalgam restorations had been prepared by eight Scandinavian dentists, were examined. The outlines of the cavity preparations were relatively large, with mean buccolingual extensions occlusally of 50% of the intercuspal distance and proximally of 40% of the length of the circumference of the proximal surface. There was a gradual increase in the size of the cavities towards the distal part of the dental arch, measured both in millimeters and in relation to the anatomic structures. The amount of hard tissue being removed varied among the operators and was possibly influenced by the dentist's ability to handle the cutting instruments. The large cavity preparations may be the result of using procedures for cavity preparation which are not adjusted to the tremendous cutting potential of modern dental instruments to produce stereotyped 'ideally designed' cavities.

Adolescent↗

PubMed1989

[Class I and II cavities for amalgam restorations].

In a Danish cross-sectional survey of replacements of fillings it was reported that a major reason for replacement of Class II amalgam restorations was bulk fractures (22). This initiated an examination of a sample of 168 Class II cavity preparations made by dentists from Denmark and other Scandinavian countries. The results showed that the Danish cavities were deepest occlusally and buccally, had the most converging proximal walls, and the broadest bucco-lingual outline occlusally. On the basis of the literature, it is not possible to evaluate the clinical significance of these differences and there is no distinct explanation why bulk fractures cause replacement of amalgam fillings more frequently in Denmark than in the rest of Scandinavia. Only a longitudinal clinical examination of the fillings may show whether the observed differences in the cavity preparations results in an increased frequency of isthmus fractures and are of importance for the longevity of the fillings.

Dental Amalgam↗