| [Purpose]The purpose of the study was to evaluate the effects of different fabrication technique and finish line configurations on marginal adaptation of IPS e.max crowns,and to provide references for clinical tooth preparation and the manufactured pattern.[Method]Twenty extracted maxillary premolar teeth without caries or defects were used,and randomly divided into 4 groups of 5,prepared with torpedo carbide instrument(group C135),round end cylinder carbide instrument(group CDC),torpedo diamond instrument(group D135)and round end cylinder diamond instrument(group DDC).After scanning 20 prepared teeth by 3 Shape Trios intraoral scanning system,the crowns were designed by its software.Three fabrication techniques were used on each tooth:conventional wax patterns and lost-wax heat-pressing technique from IPS e.max Press(group WHP),CAD/CAM milling from IPS e.max CAD(group CM)and CAD/CAM manufacturing resin patterns and lost-wax heat-pressing technique from IPS e.max Press(group RHP).The digital replica technique was used in measuring two-dimensional marginal gap and three-dimensional marginal fit of e.max CAD crown before and after crystallization firing,and after glaze firing,as well as IPS e.max Press crowns before and after glaze firing.Two-way ANOVA was performed to assess the influence on the marginal adaptation of the finish line design and fabrication techniques,and one-way ANOVA were used to assess the effects of finish line configuration or fabrication technique on the marginal fit,followed by SNK.[Result]1.The effect of different finish line design on the marginal fit of IPS e.max crownIn group WHP,the marginal gap in two-dimension and three-dimension were as follow:group C135 113.80±35.84?m and 86.35±17.30?m,group CDC 79.36±21.11?m and 71.16±16.13?m,group D135 84.23±10.51?m and 72.20±12.89?m,group DDC 88.48±24.97?m and 81.96±15.57?m.And there was no statistical difference among the finish line design group in group WHP(P>0.05).In group CM,the marginal gap in two-dimension and three-dimension were as follow:group C135 80.48±10.47?m and 98.78±11.75?m,group CDC 76.74±13.57?m and 95.52±11.36?m,group D135 90.90±17.12?m and 113.53±19.53?m,group DDC 79.36±18.48?m and 92.85±18.81 ?m.And there was no statistical difference among the finish line design group in group CM(P>0.05).In group RHP,the marginal gap in two-dimension and three-dimension were as follow:group C135 105.84± 39.39?m and 117.93±23.37?m,group CDC 56.59±18.19?m and 82.37±7.85?m,group D135 90.14±61.26?m and 100.65±37.78?m,group DDC 96.88±36.52?m and 110.79±21.67?m.And there was no statistical difference among the finish line design group in group RHP(P>0.05).2.The effect of different fabrication techniques on the marginal fit of IPS e.max crownIn group CDC,the three-dimensional marginal fit divided by the fabrication technique were as follow:group WHP 71.16±16.13?m,group RHP 82.37±7.85?m and group CM 95.52±11.36?m,which found significant difference(P=0.027<0.05).And no difference was manifested in the marginal among other fabrication technique group.[Conclusion]No significant influence was found between slight chamfer margin and deep chamfer margin in the same fabrication technique,which means both the finish line designs can be used for preparation of all-ceramic crown when considering the marginal fit.And manufactured technique had significant effect on marginal fit of e.max crown,in which the marginal fit of group WHP was smaller than the other. |
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