[Types and colors of 1 374 chair-side CAD/CAM all-ceramic restorations].

PURPOSE: To analyse the types of chairside CAD/CAM all-ceramic restorations and the color range of all-ceramic materials used so as to provide reference for the application of clinical chairside all-ceramic restoration and the color selection of all-ceramic materials. METHODS: IPS e.max CAD prostheses and related data were collected from January 2021 to December 2021 from the Department of Prosthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine. The number and type of restorations and the color of materials were investigated and analyzed by descriptive statistics. RESULTS: A total of 1 374 restorations were included, of which 624 were crown restorations, accounting for 45.41% of the total restorations. 516 cases were veneer, accounting for 37.55%; 219 were inlays, accounting for 15.94%; fixed bridges were all adhesive bridges, with the least number with only 15 cases, accounting for 1.09%. In terms of the selection of restoration materials, the use rate of low-transparent(LT) ceramic blocks was significantly higher than that of other transparent ceramic blocks. A was the most frequently used ceramic color. The most frequently used porcelain blocks for veneers were LTA2 and LTA1; for inlay were LTA3; for crowns were LTA2 and LTA3. The blocks used in the fixed bridges were all LT, and A3 color was the majority. CONCLUSIONS: Chairside CAD/CAM all-ceramic prostheses made of IPS e.max CAD materials have been widely used in clinical practice. The types of prostheses include veneer, inset, crown and fixed bridge. The most commonly used IPS e.max CAD blocks are LTA2, LTA3 and LTA1. These findings have certain guiding significance for the clinical restoration decision and the reserve of porcelain blocks in primary hospitals.

[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.