Fabrication of occlusal rims to record the maxillomandibular relation for complete dentures

Quantitative evaluation of edentulous maxillomandibular relationship record using diagnostic complete dentures fabricated by CAD and 3D printing

PURPOSE

The present study aimed to quantitatively evaluate the accuracy of the edentulous maxillomandibular relationship record for diagnostic complete dentures fabricated using computer-aided design (CAD) and three-dimensional (3D) printing.

METHODS

Six edentulous patients were enrolled. The maxillomandibular relationship obtained from diagnostic complete dentures (DiaCD test group), that obtained from complete dentures with artificial teeth in the intercuspal position (CD control group), and the centric relationship acquired by gothic arch tracing (CR standard group) were recorded, and 3D surface scanning was performed on these records. Using the CR standard group as a reference, the DiaCD test and CD control group displacements were measured in the horizontal antero-posterior, horizontal right-and-left, and vertical directions. The displacements for the DiaCD test group were compared with those for the CD control group using the Wilcoxon matched-pairs signed rank test.

RESULTS

In terms of centric relationship, the 95% confidence interval of displacement in the horizontal antero-posterior direction was (0.54-1.89) mm in the DiaCD test group and (0.32-1.34) mm in the CD control group. The inter-group difference was significant (P = 0.03).

CONCLUSION

It is feasible to record the edentulous maxillomandibular relationship using diagnostic complete dentures fabricated by CAD/3D printing, but the protrusion of edentulous patients should not be neglected.

A pilot study of digital recording of edentulous jaw relations using a handheld scanner and specially designed headgear

The present study aimed to establish and evaluate a method for recording edentulous jaw relations digitally without occlusal bases, using a handheld scanner and specially designed headgear. The headgear maintained the mandibular position. Ten edentulous patients’ upper (U) and lower edentulous jaw models (L) were prepared and scanned. A handheld scanner was used to capture the labial alveolar ridge mucosa relations in the upper and lower anterior arches directly (Dr). U and L were registered to Dr (test group). Complete dentures of patients in the intercuspal position were used to construct the relationship between U and L (control group). Differences in jaw relations in the test and control groups, in terms of vertical difference, displacement and rotation of the anterior and posterior, and displacement and rotation of the left and right were assessed using the Hotelling’s T² test. The differences in the mean values and the mean of the absolute values of the jaw relations between groups were not statistically significant (P = 0.331) and significant (P = 0.016), respectively. Our findings show that it is possible to make digital recording of edentulous jaw relations by using a handheld scanner and headgear.