Objective:To design and fabricate a new open-window customized tray by newly developed digital software,and to eval-uate its accuracy and fitness.Methods:A matte metal model of a standard mandibular Ken's class Ⅱ dental defect was selected as the initial model,scanned by a desktop scanner and saved in STL format.The model inverted concave filling,tray edge line and support bracket were completed in tray design software;handles,overflow holes and occlusal dike structures were added to complete the tray design.3D printing technology was used to produce 10 pairs of new open-window customized pallets made of polyacrylic acid.The pal-lets were scanned and the data were imported into Geomagic software,the pallet tissue surface was taken as a common area,the pallet CAD data were aligned with the 3D scanning data,and the deviation between the two was mesured by 3D deviation analysis.The"pal-let-model"data was obtained by repositioning the pallet on the initial model and imported into Geomagic software,and the"initial model"and"pallet"data were aligned to the"pallet-model"and"pallet"data respectively.The"initial model"and"pallet"data were aligned to the"pallet-model"data,and the distance deviation between the pallet inner surface data and the initial model data was measured and analyzed.Results:The average deviation of the inner surface printing accuracy of the new windowed customized pallet from the overall RMS estimate(mm)of the design data was 0.140±0.021,that of the support bracket area 0.115±0.024,and that of the free end saddle base area 0.185±0.036,respectively.The average deviation of the average gap size(mm)between the in-ner surface of the pallet and the outer surface of the initial model was 0.998±0.042,that of the support bracket area 0.1 1 9±0.048,and that of the saddle-base area of the free end 0.989±0.082,respectively.Conclusion:The new pallet made by the newly developed software has good accuracy and suitability,and can be used for the fabrication of corrective impressions for free-end dental defects.

Objective:To design and manufacture removable partial dentures with a new configuration,and to evaluate their accuracy and suitability.Method:A structure with abutment tooth preparation was designed in the mesh structure of the bracket.The resin substrate of buccal and tissue surfaces was designed using a layered method.Selective laser melting(SLM),digital light processing(DLP)and CNC cutting techniques were used to produce a pure titanium new configuration removable local denture bracket,base res-in part and crown,respectively,followed by splicing and assembling the new removable partial denture configuration(Test group).The samples in control group was a traditional design removable partial denture bracket made by SLM technology,and the final denture was completed by conventional tooth placement and filling with glue.10 samples were included in each group.The accuracy and suita-bility of the sample were examined,data were statistically analyzed.Results:The accuracy(3D deviation,mm)of the test and control group was 0.153±0.019 and 0.153±0.011(P=0.978),the overall suitability(3D deviation,mm)of the 2 groups was 0.191±0.006 and 0.187±0.007(P=0.218),respectively.Conclusion:The configurtion is simplified and more feassible to design and manufac-ture removable partial denture with proper accuracy and suitability.