Gingival inflammation by well-adapted subgingival approximal restorations.

Restorative dentistry and periodontal health are closly related. Changes which occur in the periodontal tissues during and after restorative treatments of dental caries can be expected not only on theo retical grounds but also can be observed in the daily routine practice. Various experiments have been made concerning the character of these changes. A series of animal experiments concerning the histological reaction of periodontium from different filling materials and the applied restorative procedures were carried out. They demonstrated that the gingiva after injury may heel farely soon, provided that the area concerned is free from bacterial plaque. However, in practice it appears to be difficult to meet this condition. Rough filling materials, microscopic fissures between the filling and the cavity margins and small overhangs especially situated in the clinical sulcus-are important factors favouring development of plaque accumulations. Clinicians often suppose that extending the margin of dental restorations into the gingival sulcus, is a good caries preventive measure. Several authors, however, have shown, that subgingival fillings are associated with gingival inflammation. Inflammation has been found epidemiologically more pronounced beside welladapted restorations with subgin gival margins than beside fillings with cervical margins placed supragingivally. These findings, however, are in contrast with some histological observations. It was the aim to clarify in clinical experiments whether subgingival restoration margins cause inflammation of the adjacent gingiva. The first study was to clinically and epidemiologically clarify whether gingival inflammation is more pronounced adjacent to sound tooth structure, or to well-adapted supragingival or well-adapted subgingival filling margins. Twenty-nine of 554 recruits had one restoration-free tooth, one tooth with a well-adapted subgingival margin and one tooth with a well-adapted supragingival margin among teeth 16, 24, 36 and 44-the teeth selected for this investigation. The cervical position of the filling margin was determined from the difference between the clinically estimated distance from gingival margin to cementoenamel junction and radiologically determined distance from filling margin to cementenamel junction. Gingival inflammation adjacent to sound tooth surfaces, suband supragingival filling margins was scored with the SBIndex. Plaque accumulation was measured after fuchsin staining,, using the plaque index. Filling ranged from 1 month to 14-years-old. Degree of gingival inflammation was higher adjacent to subgingival filling margins when compared to supra gingival margins or to sound surfaces. There was no significant difference in inflammatory grade between: sound surfaces and supragingival margins. Plaque accumulation was in all three instances statistically similar. These results are in contrast to histological investigations. It should therefore be clarified whether inflammation of adjacent gingiva can be caused by placement of well-adapted subgingival filling margins. A model was worked out for this purpose.