How to register static occlusion - Correlation of contemporary techniques

A working knowledge of the analytical capacities of contemporary registration methods is essential for prosthetic treatment; however, there is a paucity of studies which coherently investigate the capabilities and limitations of the various diagnostic procedures utilized for prosthetic occlusion.

The present prospective clinical study aimed to evaluate the similarities and differences among contemporary registration methods through comparative analysis.

The habitual static occlusion of 19 healthy individuals (14 women; mean age ± standard deviation, 30.8 ± 4.8 years) was analyzed 3 times a day, using shimstock foil, occlusal foil, wax registration, silicone registration, and computerized registration. The procedures were repeated after 14 days. Statistical analyses included all registrations referencing the first measurement point to assess the mean values of antagonistic contacts and the differences between these measurements. Pearson's and Kendall's correlation analyses were performed as part of the coherent mixed logistic regression model, and marginal probabilities were calculated using the registration technique and repeated measurements.

Strong correlations were found among the various registration techniques. The largest effect sizes were observed among the wax, silicone, occlusion foil, and computerized registrations (r = 0.95, P < 0.001 to r = 0.62, P < 0.001), while the lowest effect sizes were found for shimstock correlations (τ = 0.41, P < 0.001 to τ = 0.27, P < 0.001). Occlusal changes per maxillary arch were observed referencing the first measurement time with wax registration (P < 0.001; 7.4%), shimstock foil (P < 0.001; 13.8%), computerized registration (P < 0.001; 20.3%), silicone registration (P = 0.009; 66.3%), and occlusion foil (P < 0.001; 98.8%). Occlusal changes per maxillary tooth were observed from the first incisor (P < 0.001; 5.7%) to the third molar (P < 0.001; 18.1%).

The results of the present study revealed that there are strong overall correlations among the various contemporary registration techniques. The different affinities of the techniques used to register occlusal changes, however, showed differences in the measurement techniques, which should be neither over- nor underestimated. The differential tendencies of teeth to change should be considered, even if a hypervariable system is assumed.