# Innovative Stackable Multijet-Printed Templates for Precise Veneer Preparation: A Dental Technique
## 4 Discussion  
This article demonstrates a digital workflow for designing and fabricating stackable Multijet-printed templates to provide comprehensive guidance for veneer preparation in four essential steps: incisal, labial, and cervical margin preparation. The core concept of this design is to enhance the accuracy of the tooth preparation depth by incorporating a virtual tooth preparation plan with precisely engineered bur-guiding channels within the template. Several previous studies have reported different designs of tooth reduction templates used for veneer preparation [11], including a cross-shaped design [13], multiple cylindrical guide tubes [10], and an open-window design at the labial surfaces [14]. However, all of these templates only provide tooth reduction depth grooves, and the subsequent tooth preparation still primarily relies on the free-hand technique after removal of the template, which minimizes the accuracy of veneer preparation [15; 18]. Therefore, to improve the accuracy of guided veneer preparation, we designed four distinct templates to guide the clinician through the four key steps of veneer preparation. Each template is tailored to address specific areas of the tooth preparation process, with corresponding depth requirements. Figure 13: Amount of tooth volume loss observed in the 3D deviation map. Color map analysis demonstrates promising outcomes for veneer preparation utilizing stackable tooth reduction templates (RMS = 1.38 \(\pm\) 0.03 mm). The color map provides a visual representation of the reduction achieved across four different tooth surfaces, offering a clear assessment of preparation uniformity. Our tooth reduction template optimizes the margin preparation (\(\pm\)0.3 mm), addressing inaccuracies that are commonly found in veneer preparation using other tooth reduction templates [15; 18]. The results of this study also demonstrated well-controlled preparation on the labial surface (\(\pm\)0.5 mm), with seamless transitions at the incisal-cervical labial junction. The map highlights well-distributed reductions, suggesting that the templates effectively guide the clinician toward achieving consistent and controlled preparation depths. This aligns with a study by [PERSON] et al. [19], which demonstrated that guided veneer preparation using tooth reduction templates resulted in less tooth reduction compared to free-hand and silicone guides. Accurate tooth reduction, as virtually planned, is important to ensure that the required tooth reduction volume is maintained, ultimately enhancing aesthetics and bonding strength within the enamel. Several factors influence the accuracy of stackable tooth reduction templates in veneer preparation, particularly during the design of the template, the 3D printing process, and the veneer preparation phase. When designing a tooth reduction template, it is important to incorporate the estimated tooth reduction volume based on the thickness of the veneer material. This ensures uniform restorative spaces, leading to improved aesthetics. In this study, to achieve this aim, we calculated the actual tooth reduction depth at each designed site and planned the reduction virtually on digital dental casts prior to designing the tooth reduction templates. Basic virtual tooth preparation can typically be performed using the \"inward offset\" tool in CAD software [10; 19]. Alternatively, more precise virtual tooth preparation using virtual burs, as reported by previous studies, enables accurate chair-side tooth preparation simulations. This approach allows for the design and fabrication of definitive veneers for immediate cementation in a single visit [14; 20]. Furthermore, to improve control over bur movements during veneer preparation, bur-guiding channels were integrated into the tooth reduction templates for labial and cervical margin preparation. For labial preparation, an L-shaped bur-guiding channel was designed alongside handpiece access windows to enhance the control of the handpiece and bur during veneer preparation.