In Vitro Evaluation of Bond Strength to Dentin of Two Post Systems: Computer-aided Design and Computer-aided Manufacturing Fiber Posts vs Splendor Single Adjustable Post.

AIM: To assess dentin-post bond strength and mode of failure through tensile strength testing of two endodontic post systems: CAD/CAM custom-milled fiber posts vs Splendor SAP. MATERIALS AND METHODS: Thirty extracted single-rooted mandibular premolars were sectioned 2 mm coronal to the cementoenamel junction. Root length was standardized at 15 mm, and the root canals were instrumented with #20 K-files followed by 30/0.03 and 30/0.05 ProDesign Logic rotary files, under irrigation with 2.5% NaOCl, and then submitted to final irrigation with 17% EDTA. Canals were filled with gutta-percha and AH PLUS sealer. After 24 hours, the teeth were prepared for post placement to a depth of 10 mm and randomly allocated into two experimental groups (n = 15): CAD/CAM (CC) and Splendor SAP (SS). All posts were cemented with RelyX U200 dual-cure self-adhesive resin cement. The roots were embedded in acrylic resin, and the specimens were stored for 7 days in moist heat (37°C). Tensile strength testing until failure was then performed in a universal testing machine using a crosshead speed of 0.5 mm/minute. The final failure load was tabulated for statistical analysis, and the G test was used to compare the failure modes observed under light microscopy (5× magnification). RESULTS: There was no significant difference between groups regarding tensile bond strength to root dentin (p = 0.325). Conversely, failure mode differed significantly between groups (p = 0.037). CONCLUSION: The tensile bond strength observed for the CAD/CAM and Splendor SAP post systems was similar. Adhesive failure was predominant in both groups; however, the CAD/CAM custom-milled fiber posts failed predominantly at the dentin-resin cement interface, whereas Splendor SAP posts failed mostly at the post-resin cement interface. CLINICAL SIGNIFICANCE: A strong post-dentin bond is a key to the success of dental restorations and prosthetic rehabilitation. In teeth with severe coronal decay and wide canals, both of the tested systems would be able to achieve good cervical fit.

Laser acupuncture and intravascular laser irradiation of blood for management of pediatric dental anxiety.

The aim of this study was to assess the effectiveness of laser acupuncture and intravascular laser irradiation of blood (ILIB) for managing anxiety in pediatric dentistry. Eighty-four children recruited at a university dental clinic were randomly assigned to three groups: the Sham group (n = 27) underwent sham laser irradiation of three acupuncture points, the ILIB group (n = 25) underwent 10 min of ILIB, and the laser acupuncture group (LAC, n = 32) underwent 40 s of laser acupuncture over points VG20 (Baihui), PC6 (Neiguan), and the Oppression Point. The results suggest that ILIB and laser acupuncture are feasible alternatives for managing dental anxiety in children.

Sealing ability of mineral trioxide aggregate (MTA) combined with distilled water, chlorhexidine, and doxycycline.

The aim of this study was to evaluate the sealing ability of mineral trioxide aggregate (MTA Bio) combined with different mixing agents (distilled water, chlorhexidine, doxycycline), used as an apical root-end filling material. Forty-two extracted human teeth were divided into three groups (n = 12); six teeth were used as controls. Root-ends were resected at 90 degrees, 3 mm from the apex. Root-end cavities were prepared using ultrasonic tips and filled with MTA Bio plus distilled water, 2% chlorhexidine solution, or 10% doxycycline solution. Apical sealing was assessed by microleakage of 50% silver nitrate solution. Roots were longitudinally sectioned in a buccolingual plane and analyzed using an operating microscope (20× magnification). Depth of dye leakage into the dentinal walls was measured in millimeters. Results were analyzed using ANOVA and Tukey's test (P = 0.05). MTA Bio plus distilled water showed significantly higher mean leakage results (1.06 mm) when compared with MTA Bio plus doxycycline (0.61 mm), and higher, although not significant, results when compared with MTA Bio plus chlorhexidine (0.79 mm). In conclusion, replacing distilled water with two biologically active mixing agents (doxycycline and chlorhexidine) did not alter the sealing properties of MTABio. The antimicrobial properties of these combinations should be further investigated.

Microbial contamination and inhibitory effect against Streptococcus mutans from fifth-generation bonding systems.

PURPOSE: The aim of this study was to evaluate microbial contamination and inhibitory effect against Streptococcus mutans (SM) of Prime & Bond (PB), Single Bond (SB) and Excite (EX) bonding systems before use, and after 10 and 20 applications. METHODS: The bonding material was collected by applying a drop of the material directly on broth brain-heart infusion. The samples were homogenized, diluted and seeded on blood agar plates. To evaluate the inhibitory effect on SM, a drop of each bonding material was dispensed on filter discs and placed on blood agar plates. The Cochran statistical analysis was used to evaluate the total amount of viable bacteria among the different bonding systems. Comparisons between the inhibitory effects on SM were made using the Kruskal-Wallis test. RESULTS: Adhesives SB and EX presented microbial contamination (p<0.05) and inhibitory effect (p<0.05) over SM strains with statistically significant differences concerning PB. SB and EX inhibitory capacity remained after 20 applications. CONCLUSIONS: The monomer's variation in chemical composition, solvent and application technique of the bonding systems had an influence on contamination by the total number of bacteria and on the inhibitory effect on SM.