Xin Guan

This study compares the two (2D)- and three-dimensional (3D) accuracy of tooth reduction depths in porcelain laminate veneer prepared using conventional and 3D-printed guide techniques. Forty 3D-printed maxillary casts were divided into four groups: freehand (FH) (n = 10), silicone guide (SG) (n = 10), cross-shaped 3D-printed guide (3D_C) (n = 10), and stackable 3D-printed guides (3D_S) (n = 10). Butt-joint veneer preparation was performed on the left central incisor. Two-dimensional analysis was performed to assess trueness using mean absolute differences (MADs) from the planned depth at eight designated points, while precision was compared within groups. Three-dimensional analysis evaluated trueness by superimposing post-preparation scans with reference casts and precision via intra-group superimposition, with deviation errors measured using the Root Mean Square (RMS) method. One-way ANOVA and Bonferroni post hoc tests were used (α = 0.05). In 2D analysis, 3D_S exhibited a significantly lower MAD than FH at most of the measured points (p < 0.05), more accurate incisal reduction at mesial and distal points compared to 3D_C (p < 0.001), and more accurate mesial (p = 0.011) and distal (p = 0.001) cervical margin preparation than SG. In the 3D trueness assessment, 3D_S exhibited significantly lower deviation errors than FH (p < 0.001) and SG (p = 0.012) while also achieving the highest overall 3D precision with the lowest RMS (0.067 ± 0.013), followed by 3D_C (0.086 ± 0.019). Veneer preparation guided by a stackable 3D-printed guide resulted in more accurate tooth reduction depths compared to the other three techniques.

Computer-assisted implant surgery (CAIS) using 3D-printed surgical templates has become a preferred approach for improving implant placement accuracy. Despite its clinical advantages over conventional freehand techniques, CAIS remains limited by the presence of cone beam computed tomography (CBCT) metal artefacts, which compromise the 3D data alignment during implant planning and guide fabrication. This narrative review aims to explore the impact of metal artefacts on the accuracy of 3D-printed surgical implant templates and to evaluate current approaches and modifications in implant planning workflows. This article reviews accuracy studies, case reports and technology research on CAIS from the past 5 years. It summarised the CAIS clinical decision framework and data alignment methods to provide alternatives for guided implant therapy in the future. Studies indicate that metal artefacts can distort anatomical data, leading to potential misalignment in 3D data superimposition during surgical guide designs and fabrication. However, various strategies have shown promise in reducing these distortions. Accurate implant planning and template fabrication are essential to ensure clinical success. Special consideration should be given to artefact management during data acquisition. Modified workflows that account for the presence of metal artefacts can enhance guide precision and improve patient outcomes.

Achieving precise veneer preparation is essential for optimal esthetic outcome and bonding strength. Advancements in digital technology enable the design and fabrication of stereolithographic templates to guide veneer preparation, significantly improving precision compared to conventional free-hand and silicone guide techniques. Therefore, this study outlines a digital workflow for designing and fabricating a series of Multijet-printed templates following the four essential steps of veneer preparation. The proposed workflow integrates virtual tooth preparation, virtual template design, and fabrication using an additive manufacturing approach and veneer preparation guided by the stackable Multijet-printed template. The result showed that the tooth reduction depth closely matched the required tooth reduction volume in three-dimensional accuracy analysis when using this innovative approach. This marks a transformative development in CAD/CAM dentistry, offering a more predictable and precise approach for veneer preparation, ultimately leading to improved clinical outcomes.

Computer-assisted preparation of porcelain laminate veneers (PLVs) using stereolithographic templates has been developed to enhance the accuracy of tooth preparation. However, the digital workflows involved in guided PLV preparation remain inconsistently defined across various practices. Therefore, this scoping review aimed to examine publications on computer-assisted PLV preparation to identify the key stage of digital workflows involved in designing and fabricating stereolithographic templates, as well as to highlight the limitations of various template designs. This scoping review aimed to identify publications on digital workflows for designing and fabricating stereolithographic templates in computer-assisted porcelain laminate veneer preparation. A systematic search on MEDLINE/PubMed, Web of Science and Scopus identified English-language articles published from 2014 to March 2024. Eligible articles focused on digitally designed and fabricated tooth reduction templates for porcelain laminate veneers, excluding conventional tooth preparation procedures for tooth reduction assessment. Seven clinical reports were included, demonstrating various 3D data acquisition techniques for virtual patient generation. All articles described virtual diagnostic wax-ups on digital casts, with two using a virtual articulator. Only five articles documented chair-side mock-ups with resin trial restorations to evaluate planned dental esthetics. Additionally, virtual tooth preparation prior to templates design was included in only four articles. The templates were designed using different software and ranged from simple designs with access windows to complex stacked templates with rotary instrument sleeved windows. Each template design had limitations affecting tooth reduction accuracy. All articles reported printing templates in clear acrylic resin using different technologies. In conclusion, the review highlights a lack of standardization in the digital workflow for designing stereolithographic templates for PLVs. Establishing a sound protocol for designing the tooth reduction templates is essential to ensure the accuracy and consistency of veneer preparation.