Shear bond strength of luting cements to fixed superstructure metal surfaces under various seating forces

Investigating the Long-Term Success and Complication Rates of Zirconia Dental Implants: A Prospective Clinical Study

This study addresses the durability and complications of zirconia dental implants through a prospective clinical investigation. Zirconia implants are increasingly utilized in dental implantation, and a comprehensive understanding of their long-term performance is essential.

Background

Zirconia dental implants have gained attention due to their biocompatibility and aesthetics. However, research on their extended success and complication rates is limited.

Materials and Methods

A prospective clinical study involved the placement of 30 zirconia dental implants in patients requiring tooth replacement. The implants were followed up for five years. Success was defined as the implant remaining stable and functional. Complications, including peri-implant mucositis and peri-implantitis, were monitored. Statistical analysis included descriptive statistics, Chi-square test, and P-values were set at P < 0.05.

Results

The long-term success rate of zirconia dental implants was found to be 93.3%. Among the 30 implants, only 2 exhibited failure. The most common complication was peri-implant mucositis, occurring in 16.7% of implants. Notably, the incidence of peri-implantitis was limited, observed in 6.7% of implants. Statistical analysis showed significant associations between implant failure and smoking (P = 0.021).

Conclusion

Zirconia dental implants demonstrated a high long-term success rate of 93.3% over five years. Peri-implant mucositis was the predominant complication, with a relatively low occurrence of peri-implantitis. The findings underscore the potential of zirconia implants for reliable dental implantation. Addressing modifiable risk factors, such as smoking, could further enhance implant success. Continued research is recommended to validate and expand upon these outcomes.

Effect of Cement Layer Thickness on the Immediate and Long-Term Bond Strength and Residual Stress between Lithium Disilicate Glass-Ceramic and Human Dentin

This study tested whether three different cement layer thicknesses (60, 120 and 180 μm) would provide the same bonding capacity between adhesively luted lithium disilicate and human dentin. Ceramic blocks were cut to 20 blocks with a low-speed diamond saw under cooling water and were then cemented to human flat dentin with an adhesive protocol. The assembly was sectioned into 1 mm² cross-section beams composed of ceramic/cement/dentin. Cement layer thickness was measured, and three groups were formed. Half of the samples were immediately tested to evaluate the short-term bond strength and the other half were submitted to an aging simulation. The microtensile test was performed in a universal testing machine, and the bond strength (MPa) was calculated. The fractured specimens were examined under stereomicroscopy. Applying the finite element method, the residual stress of polymerization shrinkage according to cement layer thickness was also calculated using first principal stress as analysis criteria. Kruskal–Wallis tests showed that the ‘‘cement layer thickness’’ factor significantly influenced the bond strength results for the aged samples (p = 0.028); however, no statistically significant difference was found between the immediately tested groups (p = 0.569). The higher the cement layer thickness, the higher the residual stress generated at the adhesive interface due to cement polymerization shrinkage. In conclusion, the cement layer thickness does not affect the immediate bond strength in lithium disilicate restorations; however, thinner cement layers are most stable in the short term, showing constant bond strength and lower residual stress.

Effect of different surface treatments on the shear bond strength of luting cements used with implant-supported prosthesis: An in vitro study

PURPOSE

The aim of this study was to investigate the shear bond strength of luting cements used with implant retained restorations on to titanium specimens after different surface treatments.

MATERIALS AND METHODS

One hundred twenty disc shaped specimens were used. They were divided into three groups considering the surface treatments (no treatment, sandblasting, and oxygen plasma treatment). Water contact angle of specimens were determined. The specimens were further divided into four subgroups (n=10) according to applied cement types: polycarboxylate cement (Adhesor Carbofine-AC), temporary zinc oxide free cement (Temporary Cement-ZOC), non eugenol provisional cement for implant retained prosthesis (Premier Implant Cement-PI), and non eugenol acrylic-urethane polymer based provisional cement for implant luting (Cem Implant Cement-CI). Shear bond strength values were evaluated. Two-way ANOVA test and Regression analysis were used to statistical analyze the results.

RESULTS

Overall shear bond strength values of luting cements defined in sandblasting groups were considerably higher than other surfaces (P<.05). The cements can be ranked as AC > CI > PI > ZOC according to shear bond strength values for all surface treatment groups (P<.05). Water contact angles of surface treatments (control, sandblasting, and plasma treatment group) were 76.17° ± 3.99, 110.45° ± 1.41, and 73.80° ± 4.79, respectively. Regression analysis revealed that correlation between the contact angle of different surfaces and shear bond strength was not strong (P>.05).

CONCLUSION

The retentive strength findings of all luting cements were higher in sandblasting and oxygen plasma groups than in control groups. Oxygen plasma treatment can improve the adhesion ability of titanium surfaces without any mechanical damage to titanium structure.