[Short-term clinical observation of modified resin-bonded fixed partial denture utilizing tooth undercuts]

To observe a short-term clinical result of modified resin-bonded fixed partial denture(MRBFPD) utilizing tooth undercuts.

One hundred and twenty-nine patients received restoration and totally 196 missing teeth were restored with 148 MRBFPD. According to the positions of abutments in the dental arch, all the MRBFPD were divided into three groups, namely anterior prostheses (40), posterior prostheses (95) and prostheses spanning anterior and posterior (13). The prostheses were examined at 2 weeks, 1 month, 3 months, 6 months, and every year after denture delivery. Retention and marginal integrity of MRBFPD, sensibility, secondary caries and gingival bleeding index were clinically evaluated. The evaluation results were graded as good, acceptable, and bad according to modified United States Public Health service (USPHS) criteria. Survival in this study was defined at two levels: "complete" survival (survival without any debonding), and "functional" survival (survival including loss of retention on one occasion and successful rebonding of the original MRBFPD without further debonding).

The average follow-up period was 26 months. Fifteen prostheses failed and were rated as bad with USPHS criteria, and ten prostheses were evaluated as "acceptable" because the gingival bleeding index has been rated as 3 or more at one appointment but reduced to 1 or 0 after treatment. The results of the other 123 prostheses were evaluated as "good". The "complete" survival rates were 80% (32/40) for anterior prostheses, 11/13 for prostheses spanning anterior and posterior, and 95% (90/95) for posterior prostheses, while the "functional" survival rates were 80% (32/40), 11/13 and 99% (93/95) respectively. The "complete" survival rate of posterior prostheses was statistically higher than that of anterior prostheses (χ(2) = 5.433, P < 0.05). The "functional" survival rate of posterior prostheses was not only higher than that of anterior prostheses (χ(2) = 13.179, P < 0.01)but also higher than that of prostheses spanning anterior and posterior (χ(2) = 4.143, P < 0.05) statistically.

The results of this preliminary study suggest that short term survival rate of MRBFPD in posterior area was statistically better than that in anterior area. The outstanding advantage of MRBFPD is the minimum need of dental tissue reduction. However, their long-term success needs further investigation.