Aims: This in-vitro study was conducted to compare structural reinforcement with composite resin and two different types of posts in structurally compromised teeth. Methods and Materials: Forty-eight human maxillary central incisors were instrumented and obturated. Specimens were randomly divided into four groups. The control group was not compromised and was just restored with a resin composite. In the composite-reinforced group, the access cavity of the compromised teeth was restored only with composite to the cemento-enamel junction (CEJ). In the reinforced glass fiber post group, the compromised cervical area of the teeth was reinforced with a dual-cured composite and a glass fiber post. The reinforced metal cast post group was reinforced with a dual-cured composite and a casting post. The mean fracture load was measured. Data were analyzed by SPSS software using one-way analysis of variance (ANOVA) and chi-square statistical analysis tests. For pair comparison, Duncan was used. P<0.05 was considered statistically significant. Results: The highest fracture resistance values were for the non-compromised samples (170.12 ± 12.44), while the lowest values were for the compromised ones restored only with the resin composite (71.40 ± 17.00). There was no statistically significant difference between the mean fracture resistances of the fiber (129.36 ± 21.34) and cast (116.60 ± 22.60) post groups (P>0.05). Conclusion: The use of a composite resin in a root with thin walls will reinforce the compromised tooth, but the type of the post will not influence the final results.

Objectives. Given the high prevalence of the coronavirus and the high risk of virus transfer to dentists, the use of mouthwashes, which can potentially eliminate this virus, is suggested before dental procedures. Since these mouthwashes may affect the bond strength of composite resin restorations to teeth, this study was conducted to investigate the effect of recommended mouthwashes on the shear bond strength of composite resin restorations to dentin and enamel in selective etch and rinse and two-step self-etch bonding systems. Methods. Five groups of posterior teeth ( n = 15 ) were selected for five groups of cetylpyridinium chloride 0.07%, povidone-iodine 1%, hydrogen peroxide 1%, and chlorhexidine 0.2% as mouthwash and distilled water as the control group. The buccal enamel and lingual dentin of each tooth were rinsed after immersion in a mouthwash. After 20 seconds of enamel acid-etching and 15 seconds of dentin priming, they were impregnated with an adhesive, and composite cylinders were placed on the dentin and enamel surfaces of the tooth. The shear bond strength test was performed after 24 hours, and results were analyzed by ANOVA and paired t -test ( α = 0.05 ). Results. The mean shear bond strength of enamel to composite was significantly ( p < 0.05 ) higher than that of dentin to composite in each study group, but no significant difference was found between the mean shear bond strength of composite to enamel ( p = 0.199 ) and to dentin ( p = 0.335 ) after the use of mouthwashes and that of the control group. Conclusion. The use of mouthwashes used in this study did not have negative effects on the shear bond strength of composite to enamel and dentin.