PURPOSE This study assessed the effect of preparation design on marginal adaptation and also compared the sensitivity and specificity of clinical evaluation techniques for marginal accuracy of cast restorations to stereomicroscopy. MATERIALS AND METHODS Three Ivorine molar teeth of different designs were prepared. (A)-A complete crown preparation with buccal shoulder and beveled finish line. ...

Fixed dental prosthesis success requires appropriate impression taking of the prepared finish line. This is critical in either tooth supported fixed prosthesis (crown and bridge) or implant supported fixed prosthesis (solid abutment). If the prepared finish line is adjacent to the gingival sulcus, gingival retraction techniques should be used to decrease the marginal discrepancy among the resto...

The present study evaluated the marginal and internal adaptation of single-tooth zirconium dioxide (ZrO2) ceramic copings or crowns with three different finish line designs. Twenty-four steel dies were prepared for maxillary central incisor crowns with the following finish line designs: shoulder (S), rounded shoulder (RS), and chamfer (C) preparations. Twenty-four standardized ZrO2 ceramic copi...

PURPOSE Different types of tooth preparations influence the marginal precision of zirconium-oxide based ceramic single crowns. In this in vivo study, the marginal fits of zirconium-oxide based ceramic single crowns with vertical and horizontal finish lines were compared. MATERIALS AND METHODS Forty-six teeth were chosen in eight patients indicated for extraction for implant placement. CAD/CAM...

In finish-machining, geometric accuracy and surface quality m adversely affected by the tool wear at the minor flank and nose area. This paper describes an investigation into "comprehensive" tool wear estimation, including flank-, crater-. minor flank-, and nose-wear, based on an analysis of dynamic cutting force in oblique machining. The force, measured in terms of its three orthogonal compone...

In grinding operation, on-line process monitoring of dressing will ensure the quality of the grinding wheel and will achieve reproducible surface finish. The results of a study conducted to evaluate the feasibility and effectiveness of Acoustic Emission (AE) sensors in online monitoring of dressing is reported. Two aspects of the process are addressed. The first is the detection of undesired wh...