Overhanging amalgam restorations in young adults attending a periodontal department.

An important factor affecting plaque retention is the presence of amalgam restorations which are poorly contoured at the gingival margin. The aim of the study was to investigate the occurrence and effects of overhanging amalgam restorations in young adults. One hundred patients, aged 20-29 years, referred to the Periodontal Department, School of Dentistry, Belfast were investigated. Bitewing radiographs were used to examine the restorative status of the approximal surfaces of premolar and permanent molar teeth, excluding third molars. Fifty-seven per cent of the patients investigated had at least one amalgam overhang and 27 per cent had three or more overhangs visible on the radiographs. One hundred and seventy-eight (25 per cent) of the restored approximal surfaces had detectable amalgam overhangs. The mean bone level-amelocemental junction (ACJ) distance related to the approximal surfaces with overhangs was 1.77 (s.d. 1.0) mm and 37 (32 per cent) of these surfaces had bone levels which were greater than 2 mm from the ACJ. The mean bone level-ACJ distance for the other approximal surfaces of the teeth with overhangs was 1.63 (s.d. 1.2) mm. The mean bone level-ACJ distance for matching control surfaces on contralateral teeth was 1.86 (s.d. 1.2) mm. It was concluded that overhanging amalgam restorations were common in the restorations of young adults (20-29 years old) referred for periodontal treatment but were not associated with increased levels of bone destruction.