Clinical marginal and internal gaps of In‐Ceram crowns fabricated using the GN‐I system

Abstract

The marginal and internal gaps of ceramic crowns with alumina copings fabricated using a computer-aided design, computer-aided manufacturing system, were evaluated in vivo using silicone materials. Black and white silicone materials were used to record the marginal and internal gaps of 82 In-Ceram crowns before final cementation. The silicone materials were sectioned bucco-lingually and mesio-distally and viewed under a microscope to measure the thickness of the white silicone layer. Sixteen reference points were measured on each specimen. The mean marginal gaps were compared among the anterior, premolar and molar teeth, and the mean gaps at the reference points within the groups were compared by analysis of variance and the Dunnett T3 test. The mean marginal gap was 66.8 mum. There were no differences in marginal gaps among the three groups. In all the groups, the marginal gaps were the smallest, whereas the occlusal gaps were the largest. The mean marginal gaps of the In-Ceram crowns with the alumina copings fabricated using the GN-I system were within the range of clinically acceptable values.

Die spacer thickness reproduction for central incisor crown fabrication with combined computer-aided design and 3D printing technology: An in vitro study

“…Kokubo et al 23 investigated the internal gaps of 82 In-Ceram crowns produced by CAD/milling technology where the programmed die spacer thickness was set at 50 μm. The average measured internal gaps obtained ranged from 165.9 to 200.3 μm, which were 3 to 4 times greater than the programmed die spacer thickness.…”

Accuracy of Ceramic Restorations Made Using an In-office Optical Scanning Technique: An In Vitro Study

“…This technique was selected as it has been determined that using light-body addition-cured polyvinyl-siloxane impression materials for the replica technique is a reliable and commonly accepted method for evaluating clinical accuracy. [18][19][20][21][22][23][24] In addition, it has been shown that the gap-width values obtained using this technique are similar to those obtained after luting with glass-ionomer cement. 19 Other techniques for determining gap widths of dental restorations are using a light microscope directly after the restoration is placed on the prepared tooth or die stone 8 or luting the restorations on extracted teeth and then sectioning the crowns and teeth to determine the gap width.…”

Adaptación de cofias metálicas confeccionadas con dos técnicas: cera pérdida colada por centrifugación convencional y fresado de bloque blando en CAD/CAM

“…Las que presentaron mejor adaptación interna en la zona axial fueron las cofi as realizadas mediante la CPC y en la zona oclusal presentaron mejor adaptación interna la SMB. La línea de terminación es la confi guración del margen cervical de una preparación dentaria, para una corona metalcerámica podemos usar: chamfer, hombro bisel y bisel de 135º (1)(2)(3)(4)(5)(6)(7)(8). La más recomendable es la terminación tipo chamfer, por que proporciona un adecuado espacio a nivel cervical para el opáquer y la cerámica, una buena adaptación tras el proceso de colado, sufi ciente resistencia para que la cocción de la porcelana no distorsione esa adaptación y proporciona mejor escurrimiento al agente cementante (9-16).…”