A feasibility study on the use of an intraoral optical coherence tomography system for scanning the subgingival finish line for the fabrication of zirconia crowns: An evaluation of the marginal and internal fit

• Published in: Journal of dentistry 2024-12, Vol.151, p.105386, Article 105386
• Main Authors: Son, KeunBaDa, Lee, Weonjoon, Kim, Wook-Tae, Jeon, Mansik, Kim, Jeehyun, Jin, Myoung-Uk, Kim, So-Yeun, Lee, Kyu-Bok
• Format: Article
• Language: English
• Subjects: Computer-Aided Design; Crowns; Dental Marginal Adaptation; Dental Materials - chemistry; Dental Porcelain - chemistry; Dental Prosthesis Design; Feasibility Studies; Gingiva - anatomy & histology; Gingiva - diagnostic imaging; Humans; Incisor - diagnostic imaging; Intraoral scanner; Marginal and internal fit; Models, Dental; Optical coherence tomography; Subgingival finish line; Surface Properties; Tomography, Optical Coherence - methods; Zirconia crown; Zirconium - chemistry
• ISSN: 0300-5712; 1879-176X; 1879-176X
• DOI: 10.1016/j.jdent.2024.105386

•OCT enhances the marginal fit of zirconia crowns with subgingival finish lines.•Intraoral OCT can precisely scan subgingival finish lines.•Intraoral OCT outputs are superior to those of intraoral scanners.•Integrating OCT with intraoral scans yields superior crown fabrication quality. This study aimed to evaluate the marginal and internal fit of zirconia crowns were fabricated using scan data from an intraoral optical coherence tomography (OCT) scanner and an intraoral scanner (IOS) for scanning the subgingival finish line. An extracted maxillary left central incisor was prepared for a zirconia crown. The prepared tooth was placed in artificial gingiva, created using silicone with a refractive index similar to that of the tooth, ensuring a subgingival depth of 0.50 to 0.70 mm from the labial finish line. Scanning data were obtained from four types of models as follows. (1) CAD reference model (CRM) excluding the gingiva and scanned using a laboratory scanner. (2) IOS group excluding the gingiva (IOS only, IOSO group). (3) IOS group with scanned attached artificial (IOS with gingiva, IOSG group). (4) OCT post-processed data of the subgingival finish line and IOSG data (OCT group). Zirconia crowns were fabricated based on these data, and their marginal and internal fit were evaluated using the silicone replica technique. Statistical analyses were conducted using one-way and two-way ANOVA (α = 0.05). The OCT group exhibited a significantly smaller marginal gap than the IOSG group (P < 0.05). The marginal fit of the OCT group did not significantly differ from that of the CRM group (P > 0.05). The IOSG group exhibited a significantly larger chamfer gap, while both the IOSG and OCT groups had significantly larger axial gaps. Furthermore, the OCT group showed a significantly larger incisal gap (P < 0.05). An intraoral OCT system can enhance the fabrication accuracy of zirconia crowns by achieving superior marginal fit for crowns with subgingival finish lines. The use of an IOS for subgingival finish lines without gingival displacement cords may result in a suboptimal marginal fit. However, integrating OCT technology can effectively address this issue, leading to improved clinical outcomes. [Display omitted]