PURPOSE: Optical coherence tomography (OCT) has been investigated as a novel diagnostic imaging tool. The utilisation of this equipment has been evaluated through several studies in the field of dentistry. The aim of this preliminary study was to determine through basic experiments the effectiveness of OCT in implant dentistry. MATERIALS AND METHODS: To assess detection ability, we captured OCT images of implants in each of the following situations: (1) implants covered with mucosae of various thicknesses that were harvested from the mandibles of pigs; (2) implants installed in the mandibles of pigs; and (3) implants with abutments and crowns fixed with temporary cement. The OCT images were captured before cementation, after cementation, and after removing the excess submucosal cement. RESULTS: If the thickness of the mucosa covering the implant body was less than 1 mm, the images of the implants were clearly detected by OCT. In the implants were installed in pigs' mandibles, it was difficult to capture clear images of the implant and alveolar bone in most of the samples. Remnants of excess cement around the implants were visible in most samples that had a mucosa thickness of less than 3 mm. CONCLUSION: Currently, OCT imaging of implants is limited. Cement remnants at the submucosal area can be detected in some cases, which can be helpful in preventing peri-implant diseases. Still, though there are some restrictions to its application, OCT could have potential as an effective diagnostic instrument in the field of implant dentistry as well.
Cementation ; Crowns ; Dental Implants ; Dentistry ; Diagnostic Imaging ; Mandible ; Mucous Membrane ; Peri-Implantitis ; Pilot Projects* ; Swine ; Tomography, Optical Coherence*

Background: /Aim: The aim of this study was to compare the therapeutic efficacy of ablation and surgery in solitary hepatocellular carcinoma (HCC) measuring ≤5 cm with a large HCC cohort database. Methods: The study included consecutive 2,067 patients with solitary HCC who were treated with either ablation (n=1,248) or surgery (n=819). Th e patients were divided into three groups based on the tumor size and compared the outcomes of the two therapies using propensity score matching. Results: No significant difference in recurrence-free survival (RFS) or overall survival (OS) was found between surgery and ablation groups for tumors measuring ≤2 cm or >2 cm but ≤3 cm. For tumors measuring >3 cm but ≤5 cm, RFS was significantly better with surgery than with ablation (3.6 and 2.0 years, respectively, P=0.0297). However, no significant difference in OS was found between surgery and ablation in this group (6.7 and 6.0 years, respectively, P=0.668). Conclusion The study suggests that surgery and ablation can be equally used as a treatment for solitary HCC no more than 3 cm in diameter. For HCCs measuring 3-5 cm, the OS was not different between therapies; thus, ablation and less invasive therapy can be considered a treatment option; however, special caution should be taken to prevent recurrence.