Biomedical subjects

V Qvist

Publications and source records attributed to V Qvist.

At least 19 recordsLinked to original sources

PubMed1997

Marginal failures of amalgam and composite restorations.

OBJECTIVES: The aim of the study was to clinically assess marginal failures of amalgam and composite restorations. METHOD: Marginal defects with and without clinical evidence of secondary caries were evaluated by practitioners pre-operatively and after the restoration had been carefully removed. RESULTS: Analyses of 235 amalgam and 193 composite restorations with marginal failures showed that secondary caries was the most frequent diagnosis resulting in replacement. The secondary caries was predominately found along the gingival section of the restoration. A comparison of pre-operative diagnoses of marginal discrepancies, and the condition of the cavities at the site of the defects after the restorations had been carefully removed, showed fairly good consistency, but both false negative and false positive diagnoses were made. CONCLUSION: The observations indicated that diagnosis of the outer lesion of secondary caries provides a good basis for treatment planning.

Composite Resins↗

PubMed1997

Longevity and cariostatic effects of everyday conventional glass-ionomer and amalgam restorations in primary teeth: three-year results.

The aim of this study was to compare the longevity and cariostatic effects of everyday conventional glass-ionomer and amalgam restorations in primary teeth. The materials consisted of 515 Ketac-Fil glass-ionomer restorations and 543 Dispersalloy amalgam restorations prepared in 666 children, from 3 to 13 years of age, by 14 dentists within the Danish Public Dental Health Service in the municipalities of Vaerløse and Hillerød. The restorations, of which 79% were of the Class II type, were in contact with 593 unrestored surfaces in adjacent primary and permanent teeth. After 3 years, 6% of the patients had dropped out of the study, and 33% of the teeth were exfoliated with the restoration in situ. A further 37% of the glass-ionomer and 18% of th amalgam restorations were recorded as failed (p < 0.001). The frequency of failures was highest for Class II glass-ionomer restorations, which showed a 50% median survival time of only 34 1/2 months, because of many fractures, while the 75% survival time for Class II amalgam restorations just exceeded the actual 36 months (p < 0.001). Caries progression was most often recorded in surfaces adjacent to amalgam restorations, and 21% of these surfaces needed restorative treatment vs. 12% of the surfaces adjacent to glass-ionomer restorations (p < 0.001). The three-year results indicated that conventional glass ionomer is not an appropriate alternative to amalgam for all types of restorations in primary teeth. In particular, the short longevity of Class II glass-ionomer restorations could not be compensated for by the reduced caries progression and need for restorative therapy of adjacent surfaces.

Adolescent↗

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↗

PubMed1993

Resin restorations: leakage, bacteria, pulp.

Through the development of composite resin materials, the acid-etch technique and dentin adhesives, dentists can now complete perfect and permanent dental restorations--restorations with a color and shape approximating the natural tooth, with perfect marginal adaptation, and no harmful effects to the surrounding tissues, including the dental pulp. However, newer cross-sectional studies indicate that marginal defects are still the main cause of replacement of resin restorations, and that their clinical durability is shorter than that of other types. Moreover, there is no doubt that gap preventive treatments can intensify pulpal reactions to resin restorations if bacterial leakage occurs. The present thesis is based on nine previously published studies (I-IX). The aims of the studies were: to examine the possibilities of minimizing the occurrence of bacterial leakage around resin restorations through the use of various gap preventive procedures, to extend our understanding of their mode of action, and to investigate the pulpal reactions associated with restorations with and without bacterial leakage. The results of earlier research are reviewed, as well as the various methods for registration of gap occurrence around restorations. Studies I-IX are described briefly and followed by a discussion of the results, a summary and some concluding remarks.

Acid Etching, Dental↗

PubMed1993

11-year assessment of Class-III resin restorations completed with two restorative procedures.

This randomized clinical trial was initiated to study the effect of two restorative procedures on the clinical quality and longevity of class-III resin restorations. The material consisted of 52 pairs of class-III restorations in the microfilled resin Silar completed with two modifications of the conventional acid-etch restorative procedure: A) beveling of the margins of the cavity preparations, and B) treatment of the etched butt-joint cavities before filling with the dentin-adhesive NPG-GMA/ethanol together with re-etching and surface coating of the finished restorations with low viscous resin. The restorations were examined at base line and after 2, 4, 6, and 11 years. The cumulative 11-year survival rate for both types of restorations was 84%. Marginal discolorations, marginal discrepancies, and secondary caries were most often recorded corresponding to the beveled type-A restorations, whereas the esthetic quality of the two types of restorations was almost identical. Surface discolorations were most often recorded among smokers, and significant correlations were found between the patients' consumption of alcoholic beverages and corpus discoloration, surface discoloration, and surface wear of restorations.

Acid Etching, Dental↗

PubMed1992

Progression of approximal caries in relation to iatrogenic preparation damage.

The aim of the present study was to evaluate the effect of iatrogenic preparation damage on the need for operative caries treatment of approximal surfaces, adjacent to Class II amalgam restorations. The material was collected by 77 dentists from the Public Dental Child Health Service in Denmark. It consisted of die-stone models of 187 first-time Class II preparations, adjacent to 190 unfilled approximal surfaces of 58 primary and 132 permanent teeth. The cavity preparations were performed in children between 4 and 17 years of age. They were all filled with amalgam. Information about operative treatment and exfoliation or extraction of the preparation teeth and the adjacent teeth during the following seven years was obtained from the patients' records. Stereomicroscopic examination of the models revealed preparation damage on 64% of the unfilled approximal surfaces in primary teeth and on 69% of the corresponding test surfaces in permanent teeth. During the observation period, operative treatment was performed on 10% of the undamaged test surfaces in primary teeth and on 35% of the damaged ones (p less than 0.05). The corresponding figures for test surfaces in permanent teeth were 6% and 15% (p less than 0.05). It is concluded that iatrogenic preparation damage is a frequent side-effect of operative intervention with approximal caries lesions, and represents a dental health problem, since the damage increases caries progression and the perceived need for restorative therapy of the adjacent teeth.

Adolescent↗

PubMed1990

Placement and longevity of amalgam restorations in Denmark.

A survey has been made of the reasons for placement of 4932 amalgam restorations in Denmark. In patients more than 16 years of age 39% of all restorations were made because of primary caries, and 61% were replacements of failed restorations. In children 74% of the restorations in primary teeth and 84% of those in permanent teeth were inserted because of primary caries. The reasons for replacement of restorations depended on dentition, age of the patient, and type of restoration. Secondary caries was the most frequent reason for replacement of failed restorations in permanent teeth and accounted for 38% of all failures. Marginal discrepancies and bulk fracture of fillings were the other two major reasons. In primary teeth fracture and loss of fillings were the commonest reasons, whereas secondary caries accounted for only a quarter of all restorations replaced. The age of the restorations replaced ranged from 0 to 46 years, and half of the failed restorations in permanent teeth of adults were more than 8 years old. A shorter longevity of failed restorations was noted in primary teeth and permanent teeth of children.

Adolescent↗

PubMed1990

Placement and longevity of tooth-colored restorations in Denmark.

A survey has been made of the use of materials and the reasons for placement of 2542 tooth-colored restorations in Denmark. In adults 38% of all the restorations were inserted because of primary caries, and 62% were replacements of failed restorations. In children primary caries was the reason for placing 68% of the restorations in deciduous teeth and 77% of those in permanent teeth. Resin-based materials were the most frequently used tooth-colored restorative, except in the treatment of deciduous teeth, for which glass ionomer cement was used preferentially. Silicate cement was used for less than 2% of the tooth-colored restorations, and the few old silicate cement restorations were most often replaced with resin materials. The reasons for replacement of resin restorations were dependent on dentition, age of the patient, and type of restoration. Secondary caries, fracture of restoration, and loss of fillings were the most frequently recorded failures. The age of the resin restorations replaced ranged from 0 to 19 years, and half of the failed restorations in adults were more than 6 years old. In permanent teeth in children half of the failed resin restorations were replaced within 2 years, whereas half of those in primary teeth were replaced within 1 year.

Adolescent↗

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

Human pulp reactions to resin restorations performed with different acid-etch restorative procedures.

Fifty-eight experimental resin restorations were performed in intact, human premolars, using different leakage-reducing restorative procedures. These were conventional acid-etching and acid-etching followed by cavity treatment with an intermediary layer of low-viscous resin or the dentin adhesive NPG-GMA/ethanol. The teeth were extracted after 4 months and examined for pulpal inflammation/necrosis (I), reduction of odontoblasts (OR), and formation of tertiary dentin (TD). By the general linear model procedure, 91%, 34%, and 56% of the variations in I, OR, and TD, respectively, could be explained by variations in the experimental conditions. The significant independent variables were jaw, stage of root formation, width of pulp, width of cavity, marginal leakage, bacteria in the cavity, bacteria in the exposed dentinal tubules, and the restorative procedure. With regard to the restorative procedure the analyses showed that application of low-viscous resin increased the pulpal reactions OR and I, whereas cavity treatment with NPG-GMA/ethanol had no adverse biologic effect.

Acid Etching, Dental↗

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↗

PubMed1987

Replica patterns on composite restorations performed in vitro with different acid-etch procedures and dentin adhesives.

160 experimental Class V restorations using two chemically cured composite resins were inserted in extracted human teeth with conventional and modified acid-etch restorative procedures. The modifications included cavity treatment with non-composite resin, ethanol, or four different dentin adhesives. Following demineralization of the teeth the fillings were examined in the SEM concerning their replica patterns of the etched cavity walls. In vitro conditions favored resin penetration into pretreated enamel and dentin, but resulted in minor variations between different acid-etch procedures compared with those previously seen on resin restorations placed in vivo in teeth with vital pulps.

Acid Etching, Dental↗

PubMed1987