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Diabetes mellitus (DM) is diagnosed in 3% to 4% of the population. This metabolic disorder is characterized by hyperglycemia caused by the body's deficient management of insulin. Two main types of DM exist: type 1 is a total deficiency in insulin secretion, and type 2 is a combination of resistance to insulin action and inadequate compensatory insulin secretion. Diagnosis and monitoring of DM is based on blood glucose concentration or glycosylated hemoglobin concentration. The dental practitioner should be aware of the oral manifestations of DM in order to spot initial symptoms of the disease. When treating DM patients, the practitioner must understand the consequences of the disease in relation to dental treatment. In this review, we examine the implications of DM when orthodontic treatment is planned.

Objectives: The marginal quality of four tooth-coloured inlay systems was clinically investigated and subjected to computer-aided semiquantitative marginal analysis under scanning electron microscopy (SEM) after 3 years of clinical service., Methods: Three of the restoration types were made using the Cerec CAD-CAM apparatus: one was milled from preformed glass ceramic blocks, and the two other inlay types were milled from preformed porcelain blocks. The fourth system was based on an experimental indirect resin composite inlay system. Each inlay type was luted with a different luting resin composite. The clinical evaluation was performed with a mirror and explorer by two clinicians separately, and the marginal analysis was conducted microscopically on replicas (SEM x 200)., Results: After 3 years in situ, all the restorations were clinically acceptable. No recurrent caries was observed. Marginal analysis under SEM detected a high percentage of submargination for all four systems, which suggests that their respective resin composite luting agents were all subject to wear. The percentage of marginal fractures on the enamel side as well as on the inlay side did not increase dramatically compared to the 6-month results., Conclusion: The first recall after 6 months of clinical service indicated how tooth-coloured inlays behave at their margins. The 3-year results confirmed the early findings, indicating that wear of resin composite lutes is important and present in all systems. The two ceramic materials showed a similar behaviour at the margins. The resin composite inlay performed better at the inlay site than at the enamel site.

Since dentine exposed to the oral environment undergoes important compositional and morphological transformations, bonding to it differs significantly from bonding to unaffected normal dentine. In this investigation, the interface between resin and sclerotic dentine, the dentine type clinically exhibited by cervical abrasive or erosive lesions, was morphologically characterized by scanning electron microscopy after an argon-ion-beam etching procedure. The microstructure of the resin-sclerotic dentine interface was compared with that produced to normal unaffected dentine in an attempt to find reasons for the reported less reliable bonding of adhesive resins to sclerotic dentine. A resin-dentine interdiffusion zone or hybrid layer with only a limited width was formed at the hypermineralized intertubular dentine. No or only short resin tags were developed in most dentinal tubules, since their orifices were obliterated due to increased peritubular dentine apposition, intratubular deposition of irregular minerals and formation of so-called sclerotic casts. Consequently, it is reasonable to predict that dentine adhesives with an adhesion strategy, which mainly involves micromechanical interlocking by the formations of a resin-dentine interdiffusion zone combined with resin-tag development into the dentinal tubules, will be less effective when applied to sclerotic dentine than to unaffected normal dentine. An adapted adhesive treatment may be necessary to make sclerotic dentine more receptive to bonding. Further research should be directed to develop adhesive systems that bond equally well to various kinds of dentine.

From a clinical point of view, fatigue in dental restorative resins is discussed by the way that fatigue expresses itself in different forms in these materials. In vitro testing of the fatigue sensitivity of dental composites is far from conclusive: there is a need for standardized testing methodology. Some findings obtained with a recently developed fatigue machine, and interpreted as a function of masticatory stresses, indicate that the generalized form of fatigue will probably be limited to microfilled based composites.

Two commercially available dentine-adhesive systems, Tenure and Tripton, were tested in two different cavity designs by placing 132 Class V composite restorations in cervical lesions of 35 patients. In Group A, the cervical restorations were placed totally in dentine without any intentional enamel involvement. In Group B, they were placed in dentine with adjacent enamel margins bevelled and acid etched. The retention rate, the evidence of clinical microleakage, and the marginal integrity were monitored over a 2-year period. The results of this clinical investigation indicate a high failure rate when only dentinal bonding was involved. A loss rate of 30% for Tenure and 55% for Tripton was noted in Group A after 2 years of clinical service. However, both adhesive systems used in combination with micromechanical retention on the enamel border (Group B) performed extremely well with only one restoration each having debonded over the 2-year period. Identically, marginal integrity and evidence of clinical microleakage more severely deteriorated with time for the Group A restorations in comparison with their Group B counterparts. In summary, the overall results were more positive for Tenure than for Tripton. It is concluded that micromechanical retention by acid etching of the enamel margin is still indispensable for the clinical success of cervical Class V composite restorations, primarily for retention and clinical microleakage and also, but to a lesser degree, for marginal adaptation.

The wear of five posterior composites at occlusal contact areas (OCA) and contact free occlusal areas (CFOA) was evaluated in Class II cavities over a 3-year period with an accurate 3D-measuring technique. A clinical evaluation was also performed. The ultrafine compact-filled composites (Willems et al., 1992) showed acceptable OCA-wear rates ranging from 110 to 149 microns after 3 years. This is very similar to the OCA-wear rate of human enamel on molars, which is about 122 microns after 3 years. The fine compact-filled composite had an unacceptable OCA-wear value of 242 microns after 3 years. The ultrafine midway-filled composite showed an exceptionally high CFOA-wear value of 151 microns after 3 years, which gave the impression of it being gradually washed out of the cavity. Clinically, 70% of the restorations made with the ultrafine midway-filled composite showed excellent colour match after 3 years. For most of the compact-filled composites slightly opaque fillings were noted and 63% of the restorations made with one of these materials were clearly opaque. It can be concluded that the investigated ultrafine compact-filled composites can be considered as amalgam alternatives as far as their wear resistance is concerned.

Assessing the wear of both enamel and composite at a shared occlusal contact area offers the opportunity to determine the differential wear between enamel and composite on the same tooth. Differential wear measurements were carried out on five posterior composite materials with an accurate 3D-measuring technique. The distinct wear step between enamel and composite was visualized by means of scanning electron photomicrographs. Both investigated ultrafine midway-filled and fine compact-filled composites (Willems et al., 1992a) have a considerably higher differential wear value and are, therefore, less suitable for rehabilitation of posterior teeth than are the ultrafine compact-filled composites, which have, in this study, a very satisfactory differential wear rate and appear to be highly wear resistant materials suitable for use in stress-bearing areas.

The software driving the Cerec CAD/CAM system has recently been updated. In this study, the marginal accuracy of computer-machined porcelain inlays was determined using the original and the updated software. Two types of MOD cavities in Frasaco resin teeth were prepared with either sharp or rounded box corners. The distance of the occlusal and proximal marginal interface was determined using a measuring microscope. The mean occlusal interfacial distance was 52 microns for both programs. Only the box corners showed a significantly larger space, of which the mean value was approximately 200 microns. The updated version improved the marginal accuracy at the box corners. Further reduction of the interfacial distance was accomplished by rounding the sharp box corners.

This study investigates the margin quality of four different tooth-coloured inlay systems using computer-aided quantitative margin analysis under scanning electron microscopy. Three types of restorations involved chairside procedures using a commercial CAD-CAM apparatus: one type of inlay restoration was milled from preformed glass ceramic blocks, the other two inlay types were milled from preformed porcelain blocks. The fourth system was based on an experimental indirect composite inlay system. Each inlay type was luted with its respective dual-curing luting composite, which was supplied with the system. After 6 months of clinical service, all four systems revealed a significant percentage of submargination indicating occlusal wear of the luting composite. The porcelain inlays and the composite inlays luted with their respective experimental luting composite showed the best marginal adaptation. Luted glass ceramic inlays, in particular, suffered from a significantly higher percentage of inlay margin fractures (9 per cent) and marginal openings (4 per cent) than the other systems. A possible explanation is that the glass ceramic subsurface structure at the inlay-lute interface was weakened by etching with ammonium bifluoride.

A 99.5 per cent pure aluminium step-wedge served as reference for evaluating the radiopacity of 55 anterior and posterior composites. The radiopacity of all materials evaluated was compared with the radiopacity of human enamel and human dentine of equivalent sample thickness. Seventeen composites exhibited a radiopacity significantly greater than that of enamel. Some composites intended for posterior use lack the radiopacity required for posterior composite restorations.

In 1983 and 1988 a questionnaire was sent to a random sample of Belgian dentists to compare the selection of filling materials such as amalgam and gold with the tooth-coloured filling materials, composites and glass polyalkenoate (ionomer) cements, for the restoration of Class II lesions in premolar and permanent molar teeth. Despite the increasing demand for aesthetics to be considered, the use of composite resins in the posterior region only increased moderately over the assessment period, while amalgam maintained its leading position as the restorative material of choice in premolar and molar teeth. Only in situations where aesthetics played a primary role did composite resins gain over silver-based fillings. There was no change in the use of gold as an indirect restorative material. Finally, the selection rate of glass ionomers increased slightly.

The aesthetic limits of light-cured composite resins in anterior teeth are determined mainly by the size and nature of the lesion and the respective preparation. Also the shortcomings of the restorative material itself are of primary importance. The oral environment and the ageing effects ultimately limit the aesthetic expectations.