The intraoral television micromeasurement of cavity margin deterioration

Abstract

The purpose of this study was to demonstrate the clinical application of the television microscope for direct intraoral micromeasurement of cavity margin deterioration. Mesiocclusal alloy restorations were placed in fifty-one maxillary second deciduous molars. A cast gold overlay with two proximal margin observation holes, one hole in the occlusal one-third and one hole in the gingival one-third, was fabricated for each restored tooth. The mesiobuccal proximal margins of the restorations were observed by the television microscope, and the marginal deterioration was electronically measured at intervals of one week, two weeks, four weeks, 12 weeks, 24 weeks, and 36 weeks postoperatively. The average gingival marginal deterioration ranged from 4.9 microns at one week to 37.8 microns at 36 weeks; the average occlusal marginal deterioration ranged from 5. 4 microns at one week to 60.1 microns at 36 weeks. The data indicated that the gingival area of the proximal margin deteriorated at a faster rate during the first 12 weeks postoperatively, and the occlusal area of the gingival margin deteriorated at a faster rate during the last 24 weeks. Greater marginal alloy flash in the gingival area was believed to be responsible for the initial gingival deterioration, and repeated masticatory stresses was believed to be major causative factor for the occlusal deterioration during the last 24 weeks of the study.