SEM evaluation of fiber-reinforced fixed bridges

OBJECTIVES:

The purpose of this clinical trial was evaluate, using SEM, FRCFPDs, made from pre-impregnated, unidirectional E-glass fiber reinforcements (Sick, Stick Tech Ltd, Turku , Finland) and Sinfony (3M ESPE, Seefeldt, Germany) resin composite, used to replace one missing permanent tooth.

METHODS:

10 patients were recruited to participate in the study. The FRCFPD's were cemented within 7 days of the preparation. For the purpose of SEM evaluation impressions were taken for each case at baseline and at 12 month reviews. The margins of each restoration were examined at X10 – X1500 magnification. The features of the margins of the restorations and adjacent enamel were assessed in terms of marginal qualities, marginal opening, quality of preparation margins, restoration margin quality and surface quality. The following quality parameters were assigned to the margins: excellent margin, underfilled margin, overfilled margin, margin with ditching (worn margin). The data was subjected to a statistical analysis using Chi – square statistical test (Yates correction) and the Fisher exact test.

RESULTS:

Ratings for excellent margins at the tooth restoration interface ranged between 67.1% and 75 %, overfilled margins: 7.9 – 9.3 %, underfilled: 15.7 – 17.1% and margin with ditching: 0 – 7.9% Marginal openings (1.4%), marginal restoration fractures ( 0 -1.4%), marginal tooth fracture (0%), poor margin quality (1.4 – 7.1%) remained low over the period of observation. Differences between the various observation periods regarding the aforementioned parameters were statistically significant for margin quality only (p ═ 0.008).

CONCLUSIONS:

Within the limitations of the study it can be concluded that:

1. After 12 months of clinical service, the retention rate of 10 FRC FPDs was 100%.

2. The micromorphological evaluation of restoration margins using SEM revealed a statistically significant difference with respect to margin quality only.

3. Disturbance of the margin's continuity was observed mainly due to ditching of the luting cement.