Digital Determination and Recording of Edentulous Maxillomandibular Relationship Using a Jaw Movement Tracking System

Abstract

To establish a direct digital method for determining and recording edentulous maxillomandibular relationship using a custom-made jaw movement tracking system and evaluate its accuracy. Materials and methods: A novel jaw tracking system was used to record the trajectory of habitual opening-closing jaw movement, and mandibular rest position (MRP) in 10 edentulous patients. 3D surface scanning was performed on the conventional maxillomandibular impressions and facial structures of patients in MRP. The multisource data were registered using a custom-made recording tool. A plane parallel to the ala-tragus and horizontal lines was constructed 2 mm above the MRP, and its vertical position was used to determine the vertical relationship. The intersections of the trajectory passing through the plane were located, and their density distributions were analyzed. The coordinates of highest density, which presented the highest repeatability of jaw movement, were used to construct the digital maxillomandibular relationship (test group). The maxillomandibular relationship of the new complete dentures with artificial teeth in the intercuspal position was defined as the control group. The displacements of the anterior reference point and 3D deviations of the entire mandibular arch were measured and compared between the test and control groups using a Wilcoxon signed-ranks test and a one-sample t-test, respectively. Results: With reference to the centric relationship position, the maximum displacements of the anterior reference points were in the horizontal anteroposterior direction for both groups, and there were no significant differences. Compared to the control group, the 3D deviations of the entire mandibular arch in the test group were significant (95% confidence interval: 0.76 mm to 1.35 mm, p < 0.001). Conclusions: By analyzing the individual trajectory features obtained by the in-house developed jaw tracking system, a digital method for determining and recording edentulous maxillomandibular relationships was established; however, the accuracy needs to be further improved.

Which clinical and laboratory procedures should be used to fabricate digital complete dentures? A systematic review

“…The assessment results for risk of bias for different study designs are presented in Supplementary Tables 2 to 4, available online. Seven randomized controlled trials 13,[26][27][28][29][30][31] had fair to good quality, but 13 cohort studies [1][2][3]20,[32][33][34][35][36][37][38][39][40] and 3 other studies 16,41,42 were considered poor quality. The remaining studies were also considered fair to good quality.…”

“…Among 39 included studies, 7 studies 33,37,38,40,[43][44][45] assessed denture bases, 2 studies 8,36 assessed trial dentures, and 26 studies [1][2][3]5,6,[13][14][15][16][17][18][19][20][26][27][28][29][30][31]41,42,[46][47][48][49][50] investigated definitive complete dentures, including 2 studies 26,29 with implant overdentures (IOD). Four studies 32,34,35,39 assessed digital scans of impression or edentulous jaws for…”

“…Thirty-four studies 1-3,5,6,8,13-15,17-20,26-29,31,32,34-40,43-50 used the conventional impression technique, and 24 2,3,6,[13][14][15]17,18,20,[27][28][29]34,35,[37][38][39][40][43][44][45][46][47][48] of them also adopted border molded impression technique. Among studies using the conventional impression technique, 5 studies 3,38,40,43,44 used CAD-CAM fabricated custom trays after primary impression making (1 milled and four 3D-printed), and 1 study 32 produced 3D-printed custom trays after intraoral scanning.…”

“…Among studies using the conventional impression technique, 5 studies 3,38,40,43,44 used CAD-CAM fabricated custom trays after primary impression making (1 milled and four 3D-printed), and 1 study 32 produced 3D-printed custom trays after intraoral scanning. Four studies 35,36,48,49 used 3D-printed diagnostic or trial dentures as the custom trays. Fourteen studies 3,5,15,17,18,27,28,[34][35][36]43,44,48,49 scanned the impression to digitize the edentulous jaws, 12 studies 20,26,[29][30][31][37][38][39][40]45,47,50 scanned the stone casts, and 2 studies 8,13 scanned the conventional wax trial dentures.…”

“…Four studies 35,36,48,49 used 3D-printed diagnostic or trial dentures as the custom trays. Fourteen studies 3,5,15,17,18,27,28,[34][35][36]43,44,48,49 scanned the impression to digitize the edentulous jaws, 12 studies 20,26,[29][30][31][37][38][39][40]45,47,50 scanned the stone casts, and 2 studies 8,13 scanned the conventional wax trial dentures. An intraoral scanner was used to scan the edentulous jaws in 4 studies, 32,33,38,39 but dentures were not fabricated in these studies.…”