Does a face-bow lead to better occlusion in complete dentures? A randomized controlled trial: part I.

Objectives: In a double-blinded randomized controlled clinical trial, the impact of face-bow registration for remounting complete dentures (CDs) on the occlusal parameters (part I) was evaluated.

Materials And Methods: New CDs of 32 patients were duplicated and mounted after intraoral pin registration according to mean settings (group 1) and (group 2) using a face-bow (arbitrary hinge axis). The vertical dimension was reduced to the first occlusal contact point, and a bite record was fabricated in the articulator. The number of contacts and the number of teeth in contact were evaluated by a computer program (laboratory result). After randomization, half of the CDs were adjusted according to protocol of group 1 and group 2 and delivered to the patients. After 3 days (T1) and 84 days (T2), clinical static contact points and teeth in contact were counted. Contact points and teeth in contact of both groups (laboratory results) and at different moments (clinical results) were analyzed statistically with the F test and bootstrapping.

Results: Laboratory: No. 2 (face-bow) showed more occlusal contact points than no. 1 (mean setting), p > 0.05. The number of teeth with at least one occlusal contact was significantly higher in no. 2 (p = 0.027). Clinic: The mean number of teeth with at least one clinical contact point was significantly higher in no. 1 (no. 1 = 7.13, no. 2 = 5.31; p = 0.042). Extent of the vertical shift poorly correlated with number of laboratory occlusal contact points (R  = 0.017).

Conclusions: Considering the complex multistep study design, a limited number of participants, and referring to one specific arbitrary face-bow, the following conclusion could be drawn: no substantial difference by the use of the arbitrary face-bow compared to a mean setting could be determined, when changing the vertical dimension in the articulator within a remounting procedure of complete dentures.

Clinical Relevance: Further research is necessary to determine the effects of different arbitrary face-bows on the fabrication and adaptation of removable dentures.