Antibacterial Effect of Cupral® on Oral Biofilms - An In-Vitro Study.

Objective: This study aimed to assess the efficacy of Cupral®, a Ca(OH)2 and Cu2+ based materials used in endodontics, against biofilms of the oral species Streptococcus oralis, Streptococcus gordonii and Aggregatibacter actinomycetemcomitans at different maturation stages. Methods: Biofilms of the bacterial target species were grown in brain heart infusion (BHI) medium for 1 and 5 days on titanium disks (titanium, grade 4) to collect microbial communities at different stages of biofilm maturation. Biofilms were subjected to different Cupral® concentrations (4-, 15- and 50-fold dilution) to assess the antimicrobial- and biofilm dissolving effect. 0.2% chlorhexidine gluconate (CHX) solution was used as a positive control. Biovolume and antibacterial efficacy were analyzed by live/dead staining in combination with confocal laser scanning microscopy (CLSM) to quantify biofilm detachment and antibacterial efficacy. Results: All tested Cupral® concentration showed a strong antibacterial effect on tested bacterial species at all biofilm maturation stages. Efficacy of biofilms detachment was concentration dependent, i.e. higher Cupral® concentrations generally led to increased biofilm detachment. The antibacterial efficacy of tested Cupral® concentration was at least equal to CHX treatment (P=0.03). Conclusion: Cupral® shows a strong anti-biofilm efficacy and may be applied for oral biofilm treatment and control in dental disciplines other than endodontics.

Fracture Strength of Ceramic Posterior Occlusal Veneers for Functional Rehabilitation of an Abrasive Dentition.

PURPOSE: To evaluate the load at fracture and influence of artificial aging of posterior teeth occlusal veneers ("table tops") made of two different ceramics. MATERIALS AND METHODS: A total of 80 table tops were produced from feldspathic ceramic (VM) and zirconia-reinforced lithium silicate ceramic (CD) using computer-aided design/computer-assisted manufacturing (CAD/CAM). Half of the specimens from each ceramic were aged prior to the load test. RESULTS: Mean ± standard deviation (SD) load at fracture was significantly higher for CD (1,571.1 N ± 297.0 N) than for VM (573.6 N ± 86.4 N) (P < .001). After aging, load at fracture increased significantly to 1,819.0 N (± 310.6 N) for CD and to 745.2 N (± 168.3 N) for VM. CONCLUSION: The use of zirconia-reinforced lithium silicate ceramic for molar nonprep table tops should be uncomplicated according to the high load-at-fracture values. Mechanical stability of either ceramic is not compromised by aging.

Retention Forces between Titanium and Zirconia Components of Two-Part Implant Abutments with Different Techniques of Surface Modification.

BACKGROUND: The adhesive connection between titanium base and zirconia coping of two-part abutments may be responsible for the failure rate. A high mechanical stability between both components is essential for the long-term success. PURPOSE: The aim of the present in-vitro study was to evaluate the influence of different surface modification techniques and resin-based luting agents on the retention forces between titanium and zirconia components in two-part implant abutments. MATERIALS AND METHODS: A total of 120 abutments with a titanium base bonded to a zirconia coping were investigated. Two different resin-based luting agents (Panavia F 2.0 and RelyX Unicem) and six different surface modifications were used to fix these components, resulting in 12 test groups (n = 10). The surface of the test specimens was mechanically pretreated with aluminium oxide blasting in combination with application of two surface activating primers (Alloy Primer, Clearfil Ceramic Primer) or a tribological conditioning (Rocatec), respectively. All specimens underwent 10,000 thermal cycles between 5°C and 55°C in a moist environment. A pull-off test was then conducted to determine retention forces between the titanium and zirconia components, and statistical analysis was performed (two-way anova). Finally, fracture surfaces were analyzed by light and scanning electron microscopy. RESULTS: No significant differences were found between Panavia F 2.0 and RelyX Unicem. However, the retention forces were significantly influenced by the surface modification technique used (p < 0.001). For both luting agents, the highest retention forces were found when adhesion surfaces of both the titanium bases and the zirconia copings were pretreated with aluminium oxide blasting, and with the application of Clearfil Ceramic Primer. CONCLUSION: Surface modification techniques crucially influence the retention forces between titanium and zirconia components in two-part implant abutments. All adhesion surfaces should be pretreated by sandblasting. Moreover, a phosphate-based primer serves to enhance long-term retention of the components.