12-year follow-up study of silicoated resin-bonded fixed partial dentures

74 resin-bonded fixed partial dentures (RBFPD's) were placed with 61 patients consecutively, since 1986. Increased mechanical retention of the FPD's was achieved by preparation of horizontal ledges and vertical grooves. 52 were 3-unit anterior, 4 4-unit anterior, 8 6-unit anterior, 1 7-unit anterior, 8 3-unit posterior and 1 4-unit posterior restoration. 60 were cast in a NiCr-alloy (Wiron88, Bego Co.), and 13 in a CoCr-alloy (Remanium CD, Dentaurum Co.) and veneered with Vita VMK68 ceramics. All restorations were seated with Microfill pontic (Kulzer Co.) bis-GMA resin cement after silicoating with the Silicoater (Kulzer) and silane treaetment (Silicoup, Kulzer). Patients were monitored at least once a year. 29 patients were rated as drop-out, as they did not appear for recall for more than one year within the observation period. Results: 14 primary failures (19% of all retorations), i.e. retention loss of one or more retainers, were observed after a mean function time of 4.15 years. Survival rate with regard to primary failures was 0.76 after 120 months (determined by Kaplan-Meier method). 6 failed FPD's were rebonded, thus a survival rate of 0.87 after 120 months of functioning restorations was calculated. With 4 restorations veneer fractures occurred, however, the veneer could be repaired. It is concluded, that silicoated resin-bonded FPD's with a preparation design for increased mechanical retention are a viable treatment means with an acceptable success expectancy. Keywords: resin-bonded fixed partial dentures, bridgework, adhesives, clinical study