Study On The Change Of Occlusal Contact Area Of Adjacent Teeth Using "Three Dimensional Deviation Technique" In Full Crown Restoration

Objective:Digital technology was used to study the changes in the occlusal contact area of the adjacent teeth at each stage of full crown restoration。It aims to analyze the influence of the temporary crown adjacent relationship on the final restoration effect.Method:Patients who came to the Prosthodontics Department of the Affiliated Stomatological Hospital of Nanchang University from August 2020 to January 2021were selected.Under the informed consent,18 subjects who met the inclusion criteria were randomly divided into A(adjacent group)and B(non-adjacent group).Performing functional training on subjects who met the inclusion criteria and bite into the intercuspid position(ICP).Using the 3shape intraoral scanner to perform 4 digital impressions of the affected half of the dentition,and obtaining 72 optical impression files before tooth preparation,after tooth preparation,before crown cementation,and after crown cementation.Using Geomagic Qualify 2013 software’s"three-dimensional deviation chromatic scale method"to process the intraoral scan files and analyze the changes in the occlusal contact areas of the adjacent teeth at each stage of the full crown restoration.Results:1.The total occlusal contact areas of the adjacent teeth before tooth preparation were 59.52±28.23 mm~2,and the total occlusal contact areas of the adjacent teeth after tooth preparation were 73.60±28.13 mm~2,the differences were statistically significant(P<0.05).2.Group A:The total occlusal contact areas of the adjacent teeth before tooth preparation were 67.97±23.95 mm~2,and the total occlusal contact areas of the adjacent teeth before crown cementation were 57.73±28.13 mm~2,there were no significant differences between the two group(P>0.05).Group B:The total occlusal contact areas of adjacent teeth before tooth preparation were 51.07±30.97 mm~2,and the total occlusal contact areas of adjacent teeth before crown cementation were65.15±23.65 mm~2,the difference were statistically significant(P<0.05).3.Group A:The total occlusal contact areas of the adjacent teeth before tooth preparation were 67.97±23.95 mm~2,and the total occlusal contact areas of the adjacent teeth after crown cementation were 57.38±34.46 mm~2.There were no significant difference between the two group(P>0.05).Group B:The total occlusal contact areas of the adjacent teeth before tooth preparation were 51.07±30.97 mm~2and the total occlusal contact areas of the adjacent teeth after crown cementation were51.36±28.91 mm~2,there were no significant difference between the two group(P>0.05).Conclusions:1.The occlusal contact areas of adjacent teeth after tooth preparation were larger than that of adjacent teeth before tooth preparation.2.The occlusal contact areas of adjacent teeth after tooth preparation were similar to that of adjacent teeth before tooth preparation when the adjacent relationship was restored with temporary crown.The occlusal contact areas of adjacent teeth after tooth preparation tended to increase compared with that before tooth preparation when the adjacent relationship were not restored.3.Whether the temporary crown had adjacent relationship or not,the occlusal contact areas of the final restoration were similar to that of the adjacent teeth before tooth preparation.