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Porcelain laminate veneers are a conservative treatment to enhance esthetics, tooth shape, color, and contours. Enamel preservation during tooth preparation is essential for the long-term success of these micromechanically retained partial coverage restorations. Different methods have been described to clinically assess tooth preparation relative to definitive restorative contours. This clinical report describes a digital workflow to fabricate 3-dimensionally (3D) printed tooth reduction guides based on digital esthetic planning. These 3D printed reduction guides help clinicians visualize and gauge tooth preparations relative to the desired restorative contours, aid in enamel preservation, and overcome some of the limitations associated with conventionally fabricated tooth reduction guides. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to evaluate the accuracy of polyetheretherketone (PEEK) based post and core restorations using heat‐pressed and computer‐aided design and computer‐aided manufacturing (CAD‐CAM) methods. Materials and Methods: Post and core patterns (n = 10) were fabricated using an acrylic pattern resin and each pattern was scanned to generate a resin pattern standard tessellation file (STL‐R) to be used as the standard control group for the 3D profilometric analysis. The STL‐R files were loaded into a computer‐aided manufacturing (CAM) machine and a milling disk made of a modified PEEK‐based polymer with 20% ceramic fillers was milled into post and core restorations. Each original post and core resin pattern was sprued, invested and pressed using pellets made of the same PEEK material and a PEEK pressing unit. The resulting post and core restorations from the CAD‐CAM and heat‐pressed methods were scanned to generate STL‐M (milled) and STL‐P (heat‐pressed) files, respectively. STL‐M and STL‐P files were digitally aligned and compared to STL‐R files using a 3D analysis software. The 3D spatial distribution deviation was exported, and the statistical analysis was performed using the 95% CI deviation distribution from the Gaussian function subtraction. The statistical outcome for each group was merged and a 3D color‐coded map was created showing the average deviation (α = 0.05). Results: The heat‐pressed post and core restoration showed 79 ±6% of the areas within ±50 µm while the CAD‐CAM post‐and‐core restoration showed 66 ±9%. The CAD‐CAM post and core restorations show 6 ±5% of the areas above the ideal for marginal adaptation limit threshold of 200 µm, while only 0.7 ±0.7% was found for the heat‐pressed. Conclusions: The heat‐pressed method to manufacture PEEK‐based post and core restorations showed higher accuracy than the CAD‐CAM method. [ABSTRACT FROM AUTHOR]