Periodontal conditions and carious lesions following the insertion of fixed prostheses: a 10-year follow-up study.

A longitudinal study, extending over a period of 10 years, was carried out on a group of 114 patients for whom full crowns were placed. Annual records were kept of the plaque index (P1 I) and gingival index (G I) and of the distance from the crown margin to the base of the gingival crevice. The following conclusions can be drawn from this study: 1. Only small differences in P1 I scores were observed between the crowned teeth and the control teeth. 2. On the average, higher G I scores were found when the crown margins were located subgingivally as compared to location at the gingival margin or supragingivally. 3. There was a small increase in pocket depth, and a little more loss of attachment on those teeth where the crown margins had been located in the gingival pocket compared to a supragingival location. 4. When fixed prostheses are adequately made, and the patient maintains a satisfactory oral hygiene, least damage is likely to be caused to the periodontal tissues when the crown margins are located supragingivally. 5. The incidence of carious lesions was about the same whether the crown margins had been located subgingivally, at the gingival margin or supragingivally. 6. Presumably, the oral health in a group of adult patients can be kept acceptable for an extended period of time provided a prophylactic oral hygiene program is catered for.