C M Kreulen

The treatment of proximal caries has changed during the last decade. The present study evaluates a recently developed material, applied in box-only preparations in primary molars. At the twelve-month evaluation of this clinical study, it became obvious that Dyract can be an alternative for Tytin in the primary dentition, though there is some change in color of the Dyract material. In time, the marginal adaptation of Dyract seems to improve. The preparation time for both materials is comparable. The total treatment time of box-only Dyract restorations (including an occlusal sealant), however, is longer compared to conventional class II Tytin restorations. Although in both groups radiolucencies were found at the baseline radiograph evaluation, no sign was found of secondary caries. One recurrent caries lesion was found adjacent to a Dyract restoration. It should be emphasized that one-year data do not indicate the longterm success of restorations.

Fluoride-releasing materials have been reported to be bactericidal in vitro. This may be of benefit to modern dentistry, which is directed to the preservation of tooth tissue during restorative treatment. Little is known about in vivo effects. The aim is to investigate the influence of a resin-modified glass ionomer cement (RM-GIC) on carious dentine that remains under restorations, compared to amalgam. Using a split mouth design, 40 molar pairs in 40 patients (mean age 14.9 years) were selected, based on clinically and radiographically diagnosed occlusal dentine caries. Under aseptic conditions, the enamel was removed and the carious dentine was sampled just beneath the dentino-enamel junction using a round bur. Without further removal of carious dentine, the molars of a pair were alternately restored with RM-GIC or amalgam. The colour and the consistency of the carious dentine were assessed. The samples were processed for microbiological determination of total viable counts (TVC), mutans streptococci (MS), and lactobacilli (LB). After 6 months the molars were reopened, similarly sampled and evaluated, and then permanently restored after complete caries removal. For both materials a substantial decrease in the numbers of TVC, MS and LB was found after the 6-month period. Also a positive effect was observed on the colour and the consistency of the remaining carious dentine, which was comparable for the two materials. RM-GIC showed a significantly larger decrease in counts of MS and LB than amalgam, but not for TVC. Since in only few cavities the number of bacteria decreased under the level of detection, it is still considered essential to remove all carious dentine during restorative treatment.

Ideally, in view of rational practice management, the same GIC material may be used as a restorative material as well as a sealant material. The aim of this study is to compare the retention rates of a GIC designed as sealant material (Fuji Type IIIR,) and a glass-ionomer restorative material (Fuji Type IXR). In a clinical trial using a split mouth design, 104 children (mean age 10.4 years, s.d. 1.2) of the Centre of Youth Dental Health Paramaribo (Surinam) received 208 sealants, 104 per material. The sealants were placed in upper or lower first or second molars by dental auxiliaries. Moisture control was achieved by cotton rolls. After four and nine months the retention of the sealants was checked clinically. For the evaluation at both times 99 molar pairs were available. After four months 46 percent of the Fuji IIIR and 72 percent of the Fuji IXR sealants showed complete retention. After nine months these percentages were 15 percent and 52 percent, respectively. In view of the study design, Relative Risks (RR), and their 95 percent confidence intervals, were calculated. Converted to chance to total absence, the chance to absence of the material for Fuji IX was about 60 percent less than that for Fuji III (four months RR = .44 (.25 - .80) and nine months RR = .42 (.39 - .45)). In conclusion the GIC restorative material showed to be more retentive then the GIC sealant material.

Two methods of evaluating the occlusal marginal adaptation of posterior restorations are compared: a direct and an indirect method. The direct method uses modified Ryge criteria and assessments are performed with mirror, probe and operating lamp. With the indirect method assessments are conducted using photographs of impressions of the restorations. For the purpose of the comparison a selected group of newly placed amalgam and composite restorations is used and attention is paid to a 'section method' of observation. This routine of localization the parts of the outline to be measured, permits independent comparison of the assessments. The two methods were applied by pairs of observers and the indirect photographic method appears to be more reliable (percentual agreement between observers 97 percent versus 80-91 percent for the direct method). The agreement between the indirect and direct methods is rather low. The indirect photographic method is more valid when compared to a yardstick, especially if few deficiencies of the margin are expected. It is not clear which method is preferable if more deficiencies occur with restorations of higher age.

This paper describes the results of an evaluation of the occlusal marginal adaptation of Class II restorations in a clinical trial. The margins of 183 resin composite and 61 amalgam restorations, made by three dentists, were assessed. An indirect evaluative method has been applied, that uses a shadowing photographic technique to produce images of impressions. The restorations were classified into excellent and nonexcellent marginal adaptation categories and on this basis influencing factors were determined. Resin composite restorations appeared to show more 'excellent' margins than amalgam restorations (64.5 percent and 21.3 percent, respectively). The variable mainly influencing the marginal adaptation of the composite restorations was the dentist. In addition, the influence of an occlusal level is discussed, since a difference of marginal adaptation between bevelled and nonbevelled parts of the occlusal outline was observed.

Time registrations for indirect class II resin composite inlays are given. They are compared with treatment times for direct resin composite restorations.

In this article, the baseline results of radiographic evaluation of both Class II resin composite and Class II amalgam restorations are discussed. Attention is paid to the quality of the cervical margin adaptation, the occurrence of radiolucencies adjacent to the restoration, and the homogeneity of the resin composite.

This article describes the results of an investigation into the treatment time required for the placement of Class II composite resin restorations. For purposes of this study, three dentists made 183 standard Class II composite resin restorations, both two-surface and three-surface, according to a detailed treatment protocol. Time registrations were carried out during the treatments, and each treatment was divided into five sections, each representing one stage in the restorative process. Of the various factors which may affect treatment time, the following were studied: the dentist; the type of tooth; the type of restoration; and the presence of an existing amalgam restoration in the tooth to be restored. Following in transformation of the treatment times obtained, an analysis of variance was employed. In this study the average treatment time for Class II composite resin restoration was 41.8 minutes. The results indicated that the factors mentioned above significantly affect the treatment time. In addition, the treatment time of one of the dentists was influenced by a marked learning effect.

Postoperative sensitivity is one of the problems a dentist can encounter after restoration of a tooth with composite resin. To reduce the possible causes of these complaints, the operative procedure has been adapted to some suggestions of other investigators. In this study the postoperative sensitivity was evaluated in a comparison between composite resin and amalgam: 244 (standard) class II restorations were made by three dentists in fifty-six patients. Each patient received one or two series of four experimental restorations: three of composite resin (Herculite XR, Clearfil Ray Posterior, Visiomolar) and one of amalgam (Tytin). All restorations were made according to a fixed protocol. The occurrence of postoperative sensitivity was recorded. Fifty-seven restorations showed a varying period of postoperative sensitivity; no case lasted longer than half a year. Molars have more postoperative sensitivity than premolars; the difference, however, is not significant (P greater than 0.05). The study shows further that there is no difference in postoperative sensitivity between restorations of composite resin and those of amalgam. The occurrence of postoperative sensitivity does not seem to be influenced by the choice of treatment procedure, type of tooth (premolar/molar), or by the patient or the dentist.