Proximal contact loss between implant-supported prostheses and adjacent natural teeth: a retrospective study

To determine the prevalence of proximal contact loss between posterior implant-supported prostheses and the adjacent anterior natural tooth and to identify potential contributing factors.

Forty-five consecutive patients, who had received either implant-supported fixed partial denture (FPD) or implant-supported single crown (SC) in the posterior region and were under regular review, were recruited. Interproximal space was assessed by the number of matrix bands that could be placed, and tooth mobility was assessed by Periotest®. A self-reported questionnaire was administered. Effects of various patient and prosthesis parameters on interproximal space were analyzed by Kruskal-Wallis test or Mann-Whitney U test. Correlations were tested by Spearman's rank correlation coefficient. Differences were considered significant if P < 0.05.

Forty-three of 66 (65%) prostheses showed proximal contact loss. Frequent food packing was reported in 40% of the prostheses. The mean interproximal space was 167 (SD = 125) μm, and it was positively correlated with patients' age (P = 0.031) and time since prostheses delivery (P = 0.002). The interproximal space in the FPD group was significantly larger than the SC group (P = 0.008).

Proximal contact loss is not uncommon in posterior implant-supported prostheses. In this study, age of the patient, prosthesis type and time since delivery of prosthesis were found to be contributing factors.