Influence of loading forces on the vertical accuracy of interocclusal records

Objective: To evaluate the influence of loading forces on the vertical discrepancies caused by interocclusal recording materials. Method and Materials: A custom-made apparatus was used to simulate the maxilla and mandible. Eight interocclusal records were made in each of the following groups: G1- Aluwax (aluminum wax; Aluwax), G2-Beauty Pink wax (hydrocarbon wax compound; Miltex), G3-Futar D, G4-Futar D Fast, G5-Futar Scan (polyvinyl siloxanes; Kettenbach), and G6-Ramitec (polyether; 3M ESPE). The vertical discrepancies were measured by an inductive displacement transducer connected to a carrier frequency amplifier after storage of the records for 1 hour at room temperature. Different compressive loading forces up to 1 kg were applied onto the upper part of the apparatus to evaluate the influence on the vertical discrepancies of the records. Two-way ANOVA was used for statistical analysis. Results: The compressive loading force had a statistically significant influence on the vertical discrepancies (P .01) (ie, higher forces reduced the vertical discrepancies). When a compressive force of 1 kg was applied to the upper part of the apparatus, the mean vertical discrepancies for G1 (11 ± 3 µm) and G2 (12 ± 3 µm) were statistically significantly higher than in groups G3 (1 ± 1 µm), G4 (2 ± 1 µm), G5 (0 ± 1 µm), and G6 (-2 ± 2 µm). Conclusion: A compressive force of 1 kg could be used to stabilize the cast during mounting procedures in an articulator using an interocclusal record made of polyvinyl siloxane without vertically changing the interocclusal relationships. Keywords: aluminum wax, compressive force, dental material, hydrocarbon wax compound, interocclusal record, polyether, polyvinyl siloxane