The influence of restorative materials on marginal gingiva.

BACKGROUND: A great variety of dental materials are now available for use in restorative treatments. Much attention has been devoted to physical and chemical properties, but the biological effects of these materials have been less frequently studied. AIM: The aim of this study is to test the influence of resin based restorations, amalgams and gold alloys, as restorative materials in immediate contact with the gingival tissues. METHODS: In 103 patients (54 male and 49 female, 39 smokers and 64 non-smokers, mean age: 34 +/- 13 years) with 255 restored teeth (101 resin-based materials, 98 amalgams, and 56 gold inlays), the marginal gingiva was examined. The restorations selected had to be in place more than 6 months. The patients participating in the study had no systemic diseases and pregnant patients were excluded, as were those under long-term medication and those with severe periodontal disease. The filling materials were examined for surface roughness, secondary carious lesions and gaps. The marginal gingiva in contact with the restorative materials was tested by reference to Bleeding Index (BI), Gingiva Index (GI), probing depth and degree of tooth mobility. As controls 255 teeth without fillings, of the same type, in the opposite jaw were used. RESULTS: The 101 resin-based restorations had a mean age of 3.1 (+/- 2.0) years, the amalgam fillings were in place 6.6 (+/- 4.1) years and the gold inlays had an average age of 4.7 (+/- 4.6) years. Surface roughness was observed in 66.3% of the resin-based restorations, in 47.9% of the amalgams and in 10.7% of the gold inlays. Absence of bleeding after probing was observed for 25.7% of the resin-based restorations, for 55.1% of the amalgam fillings, and for 58.9% of the gold inlays. All classes of restored teeth showed significant differences from the controls without fillings. The mean probing depth for the resin-based fillings was 3.6 mm (control 2.4 mm), for teeth with amalgams 3mm (control: 2.4 mm) and for teeth with gold inlays 2.5 mm (control 2.1 mm). A significant difference between smokers and non-smokers was only found in the group of resin-based restorations. The Bleeding Index was significantly higher in the group of smokers (p = 0.0005) in comparison to the non-smokers, as was the Gingiva Index (p=0.0106). CONCLUSION: The marginal adaptation of the restored teeth examined showed materially specific differences. The handling of resin-based materials, in comparison to amalgam or gold remains very sensitive and consequently there is prevalent error of technique. The high prevalence of gingival irritation in association with resin based materials may be caused by non-indicated applications, failures of technique, or simply the chemical properties of the materials.