Enhancing Incremental Composite Placement Training with 3D‐Printed Enlarged Tooth Models

Incremental layering is a foundational technique in composite resin placement, essential for minimizing polymerization shrinkage, ensuring optimal adaptation, and enhancing the longevity of restorations [1]. However, in preclinical training, students practice on natural-size manikin teeth, making it difficult to visualize and assess thin layers of composite during placement. This limitation contributes to frequent challenges in proper layer placement and maintaining awareness of opposite walls, both critical for developing a clinical technique. This study explored the use of enlarged, non-tooth-colored 3D-printed models [2, 3] to enhance understanding of composite layering. The increased size and color contrast [3] help students better visualize incremental layering. The goal was to evaluate how this training impacts students' understanding, knowledge, and confidence in composite placement. An open-source premolar file was used to 3D-print tooth models enlarged to 20 times their natural size using a SprintRay printer with ProCure, Die & Model gray 2 resin (Figure 1). Preclinical (D1s), and clinical (D3s andD4s) students were recruited (IRB: HP-00112142) and chosen for their varied levels of knowledge and experience with composite placement. The training included instructions, a demonstration, and a brief explanation of its clinical relevance. Students practiced on the enlarged model before repeating the procedure on the manikin tooth, followed by a questionnaire evaluating the training's effectiveness and impact on their confidence and knowledge. Cross tabulations of class year and survey responses were analyzed using Chi-square tests (α = 0.05) in SPSS v.30. Ninety-seven students participated (81 preclinical, 16 clinical). Overall satisfaction was high: 88% of preclinical and 94% of clinical students rating the experience as good to excellent (p < 0.001, Figure 2A). When asked which model best supported their understanding of incremental composite placement, 81% of clinical students preferred 3D-printed model, while preclinical students were more divided favoring typodont teeth or both equally. Likewise, 88% of clinical students found the 3D-printed models more helpful for identifying anatomical features, compared to 43% of preclinical students (Figure 2B). These differences reflect the greater clinical experience of advanced students, allowing them to better recognize the educational value of enlarged models. In response to the statement, “I expect that this exercise will positively impact my manual dexterity”, 96% of preclinical and 72% of clinical students agreed (p = 0.903), though some clinical students remained neutral, possibly due to prior confidence in their skills. Nonetheless, 100% of clinical and 91% of preclinical students recommended the 3D-printed model for preclinical use (p < 0.001). In addition, 84% of preclinical and 94% of clinical students intended to apply the technique in practice (p < 0.001). Confidence also improved: 90% of preclinical and 100% of clinical students agreed that the training enhanced their ability to place composite restorations (p < 0.001), and 63% reported reduced stress during the procedure (Figure 2C). Qualitative feedback suggested adding anterior and posterior teeth, slightly reducing model size to minimize material use, color-coded layering, and visual diagrams during practice. 3D-printed teeth models have been successfully used across various areas of dental education [2, 3], with previous studies reporting positive feedback on color contrast [4], reduced stress, and increased confidence [5]. The training was highly valued across experience levels, with 3D-printed models significantly enhancing confidence, understanding, and perceived clinical preparedness. The authors would like to thank Dr. Tomás Rivera for his support in producing the 3D-printed models. The authors declare no conflicts of interest.