[Assessment of the reproducibility of occlusal morphology for digital full crown designed by mandibular trajectory data].

PURPOSE: To metrically assess the reproducibility of mandibular trajectory data and mean frame parameter in guiding the design of occlusal morphology of prosthesis. METHODS: Fifteen subjects with complete dentition were selected, including 6 females and 9 males, with an average age of 22-30 years old. The mandibular trajectory data and mean frame parameter were used to guide the design of occlusal morphology of the prosthesis in the CAD system, then the occlusal morphology was compared to the original natural teeth. The data were statistically analyzed by SPSS 25.0 software package. RESULTS: The general deviation of occlusal morphology between the prosthesis guided by mandibular trajectory data and mean frame parameter with the natural teeth was as follows: mean positive distance was (269.9±63.1) µm, (318.7±51.3) µm; mean negative distance was (-175.8±78.2) µm, (-253.7±65.6) µm; root mean square (RMS) was (267.1±84.9) µm and (304.1±82.2) µm. The vertical distance on mesial buccal cusp was (197.6±86.2) µm and (288.0±79.6) µm，distal buccal cusp was (176.3±85.3) µm and (297.7±63.2) µm, mesial lingual cusp was (171.6±62.4) µm and (246.4±62.8) µm, distal lingual cusp was (166.2±64.6) µm and (232.5±70.7) µm, central fossa was (104.9±42.2) µm and (219.1±69.1) µm. RMS, mean(-) and vertical differences of central fossa and distal buccal cusp were significantly different(P＜0.05). CONCLUSIONS: The occlusal morphology of the prosthesis designed under the guidance of mandibular trajectory data and mean frame parameter both have significant differences with natural occlusion, but the deviation guided by mandibular trajectory data is lower.