# Innovative Stackable Multijet-Printed Templates for Precise Veneer Preparation: A Dental Technique
## 4 Discussion
To ensure proper alignment of the handpiece access window and bur-guiding channels with the burs' dimensions, a commonly used high-speed handpiece and the specific burs for veneer preparation must be scanned in STL format for template design. However, for the cervical margin preparation, a cost-effective modification of a diamond bur with a stopper was proposed to fit into the curved bur-guiding channel within the template, optimizing margin preparation accuracy. A similar approach is observed in a commercially available First-fit system for veneer preparation; however, unlike our approach, a First-fit system requires a specially designed handpiece to accommodate the rotary instrument access windows, leading to higher equipment costs. Verifying the virtual positioning of the burs, as described in this study, is recommended. This step ensures that the actual bur position aligns correctly with the intended tooth surfaces, thereby improving the precision of veneer preparation. In addition, two distinct templates for labial reduction were designed to maintain the two planes of the labial surface during veneer preparation--one for the incisal half and another for the cervical half. Nevertheless, the inclusion of handpiece access windows in both tooth reduction templates increases their bulkiness, which may pose challenges for patients with limited mouth opening. Several factors associated with 3D printing also affect the accuracy of templates in tooth reduction, including the 3D printing technology employed, parameter settings during the printing process, and post-processing procedures [21; 22; 23]. Compared to Stereolithography (SLA) and Digital Light Processing (DLP) technologies, the Multijet Printing (MJP) technology used in this study demonstrates advantages in high-speed printing, excellent surface smoothness, and exceptional detail resolution. In this study, a class VI biocompatible photopolymer resin was used with UV curing and a 45\({}^{\circ}\) build orientation to ensure high dimensional stability and printing precision [24; 25], which are critical for accurate tooth reduction guidance. The translucency of the resin material is beneficial in further facilitating visual inspections of bur positioning and movement during the tooth preparation process, thus enhancing clinical control and accuracy [26; 27]. The stackable tooth reduction template introduced in this study offers several clinically significant advantages in veneer preparation. First, by standardizing reduction depths across critical regions (incisal edge: 1.5 mm, labial surface: 0.5 mm, cervical margins: 0.3 mm) through guided bur movement, this approach significantly reduces operator dependence, a persistent limitation of conventional veneer preparation techniques [6; 7]. This allows clinicians with varying levels of clinical experience to consistently achieve enamel-preserving preparations, especially at the cervical margins, which are critical for long-term bonding success [4; 5], while potentially minimizing postoperative sensitivity and the risk of restoration failure. Second, the sequential guidance in veneer preparation improves clinical efficiency by eliminating the need for repeated depth checks required when using conventional silicone guides. In addition, this innovative technique is compatible with standard burs and integrates easily with CAD/CAM workflows, making it well suited for modern digital prosthodontics and enabling same-day veneer fabrication when combined with intraoral scanning [17; 21]. While the innovative guided veneer preparation approach presented in this study shows promising results, certain limitations should be acknowledged. This study primarily focuses on the digital workflow for developing stackable tooth reduction templates without providing a comparative analysis against other veneer preparation techniques.