Hirofumi Kaneko

Background: The association between oral health and gastrointestinal (GI) cancers has been primarily investigated within a periodontitis-centered framework. However, the potential contribution of cumulative oral disease burden, including dental caries and apical pathology, remains insufficiently explored. The Decayed, Missing, and Filled Teeth (DMFT) index reflects lifetime exposure to oral microbial dysbiosis and chronic inflammation. Methods: This retrospective exploratory study included patients with GI cancers referred for perioperative oral screening and management at a tertiary care center between 2015 and 2025. Oral health was evaluated using the DMFT index, periodontal probing depth, and radiographically diagnosed apical periodontitis. Age-stratified DMFT and periodontal parameters were compared with national reference data, while apical periodontitis prevalence was descriptively assessed. Results: Patients with GI cancers demonstrated higher DMFT values than national averages across most adult age groups. The prevalence of periodontal pockets (≥4 mm and ≥6 mm) was also elevated. Apical periodontitis was common, affecting 46.3% of patients, with some age groups exceeding 50%. Overall, these findings indicate oral disease clustering with coexisting chronic oral conditions. Conclusions: Patients with GI cancers exhibit substantial oral disease burden, including increased caries experience, periodontal pathology, and apical lesions. These findings suggest that the oral–gastrointestinal cancer relationship may extend beyond a periodontitis-centered paradigm, and that cumulative oral disease burden—including cariogenic processes—may represent an underrecognized component of this axis. The DMFT index may serve as a surrogate marker of lifelong oral inflammatory exposure. While causal relationships cannot be established, this study provides a basis for future mechanistic and longitudinal investigations.

Tooth bleaching is a widely used esthetic treatment; however, bleaching agents can temporarily alter the surface morphology of enamel, increasing surface roughness and porosity, which may lead to increased susceptibility to discoloration. This in vitro study investigated the effectiveness of fluoride varnish in preventing immediate discoloration of bovine incisors after bleaching. Specimens were bleached with 35% hydrogen peroxide and treated with either Clinpro White Varnish (CW) or Enamelast Fluoride Varnish (EN), whereas control specimens received no treatment after bleaching. The samples were immersed in coffee for 24 h, and the color difference (ΔE₀₀) was calculated using the CIEDE2000 formula. The surface morphology of enamel was examined using SEM. The fluoride varnish groups showed significantly lower color difference values than the control group (p < 0.05), with ΔE₀₀ reduced by approximately two-thirds in both the CW and EN groups. SEM observations showed that the enamel surfaces in the varnish-treated groups exhibited reduced surface irregularities compared to the untreated group, suggesting remineralization. These results suggest that the immediate application of fluoride varnish after bleaching can effectively reduce short-term discoloration by providing physical protection and promoting remineralization. Fluoride varnish may serve as a simple and effective strategy to maintain whitening outcomes and minimize early discoloration.

Background: This study aimed to evaluate the color-matching and light transmission properties of a newly developed aesthetic flowable resin composite, OCFB-001. Methods: Rubber molds containing cylindrical cavities were filled with Estelite Sigma Quick, and 40 resin composite (CR) molds with simulated Class I cavities were prepared in shades A1, A2, A3, and A4, resulting in a total of 160 samples. Following bonding procedures, four different flowable resin composites (n = 10) were introduced into the cavities. The color difference (ΔE₀₀) was calculated using two methods. A two-way analysis of variance was performed, and the interaction was significant, so a post hoc analysis was performed for each shade using Bonferroni’s correction. The morphology of the filler in each material was observed via scanning electron microscopy (SEM). Results: In the A1 shade, OCFB-001 demonstrated color differences comparable to those of other materials. However, in the A2, A3, and A4 shades, OCFB-001 exhibited significantly lower color differences (ΔE₀₀) than the other materials, with a more consistent distribution. SEM analysis revealed that the OCFB-001 structure resembled that of Estelite Bulk Fill Flowable. Conclusions: OCFB-001 showed excellent shade matching in the A2, A3, and A4 ranges and good matching in the A1 shade, on par with existing universal-shade flowable bulk-fill resin composites.