Evaluating the Feasibility and Accuracy of Digitizing a Maxillary Defect Model Simulating Various Trismus Conditions

To compare the feasibility and accuracy of using intraoral scanners to digitize a maxillary defect model simulating various trismus conditions.

Four intraoral scanners were used to digitize a maxillary defect model simulating four different degrees of trismus (mouth opening = 10, 20, 30, and 40 mm), and the scanned areas were compared. The scans were also superimposed on each other for precision analysis and on reference data for trueness analysis using 3D evaluation software. Two-way ANOVA was used to compare area, precision, and trueness among scanners and among conditions.

The surface area for which 3D data were obtained by the intraoral scanners ranged from 2,672 to 6,613 mm². Significant differences were observed between the scanners (P < .001) and between the trismus conditions (P < .001), with a smaller scanned surface area in severe trismus (10 mm). Trueness ranged from 0.033 to 0.301 mm, and precision from 0.022 to 0.397 mm. Significant differences in trueness and precision values were found among the scanners (P = .001 and P = .001, respectively), but not the trismus conditions (P = .260 and P = .075, respectively).

Although trueness and precision differed between intraoral scanners, digitization of the maxillectomy model simulating various trismus conditions appears to be feasible from the perspective of accuracy with all of the scanners used. The smaller scanned surface area in the severe trismus condition was due to lack of data on the defect site in that condition.