Two‑year clinical performance of indirect restorations fabricated from CAD/CAM nano hybrid composite versus lithium disilicate in mutilated vital teeth. A randomized controlled trial

TRIAL DESIGN

This is a randomized, controlled, superiority, double-blinded, parallel-group, two-arms trial with an allocation ratio of 1:1. The aim of this trial was to compare the two-year clinical performance of partial indirect restorations fabricated from CAD/CAM nano-hybrid composite and ceramic lithium disilicate blocks using the modified USPHS criteria.

METHODS

In two parallel groups (n = 50 restorations), fifty participants having mutilated vital teeth with a minimum of two remaining walls were randomly enrolled in this trial and received indirect restorations of either nano-hybrid composite resin blocks (Brilliant, Coltene, Switzerland) or Lithium Disilicate (IPS Emax CAD). The restorations were assessed using modified USPHS criteria by two independent blinded assessors at baseline, six months, one-year and two years follow-up visits. Categorical and ordinal data were presented as frequencies and percentages. Categorical data were analyzed using the chi-square test. Ordinal data were analyzed using the Mann-Whitney U test for intergroup comparisons and Freidman's test followed by the Nemenyi post hoc test for intragroup comparisons. Numerical data were presented as mean and standard deviation values. They were analyzed for normality using the Shapiro-Wilk test. Data were found to be normally distributed and were analyzed using the independent t-test. The significance level was set at p ≤ 0.05 within all tests.

RESULTS

Forty-eight participants received the allocated intervention and completed the follow-up periods. There was a statistically significant difference between both tested materials for all USPHS criteria regarding Marginal integrity and Marginal discoloration at six-months Follow-up, but with no statistically significant difference at one- and two-year follow-up.

CONCLUSIONS

Both materials showed an acceptable, successful clinical performance along the two-years follow-up period.

CLINICAL RELEVANCE

The CAD/CAM nano-hybrid composite blocks are as reliable as Lithium disilicate for restoring mutilated vital teeth.

Comparative evaluation of mechanical and physical properties of a new bulk-fill alkasite with conventional restorative materials

PURPOSE

The physical and mechanical performance of a newly commercialized dental restorative material (alkasite) was compared with glass ionomer cement (GIC) and nano-hybrid composite.

METHODOLOGY

Human extracted premolars were used to investigate the shear bond strength. Restorative materials were placed on the dentine surface and were aged in deionized water for 14 days. The 3-D surface roughness was evaluated before and after chewing simulation cycles (50,000). The samples were fatigued mechanically using a chewing simulator and investigated with a scanning electron microscope (SEM).

RESULTS

For shear bond strength, alkasite showed significantly high values than GIC, whereas non-significant difference was observed between alkasite and nano-hybrid composite. After the chewing simulation (50,000 cycles), non-significant difference was found between GIC and nano-hybrid composite, where surface roughness values were highest for GIC and lowest for alkasite.

CONCLUSION

The newly developed restorative material (alkasite) has shown better results than existing restorative materials.

Influence of modeling agents on the surface properties of an esthetic nano-hybrid composite

Objective

The aim of this study was to evaluate the influence of different modeling agents on the surface microhardness (Vickers hardness number; VHN), roughness (Ra), and color change (ΔE) of a nano-hybrid composite with or without exposure to discoloration by coffee.

Materials and Methods

Sixty-four cylinder-shaped nano-hybrid composite specimens were prepared using a Teflon mold. The specimens' surfaces were prepared according to the following groups: group 1, no modeling agent; group 2, Modeling Liquid; group 3, a universal adhesive (G-Premio Bond); and group 4, the first step of a 2-step self-adhesive system (OptiBond XTR). Specimens were randomly allocated into 2 groups (n = 8) according to the storage medium (distilled water or coffee). VHN, Ra, and ΔE were measured at 24 hours, 1 week, and 6 weeks. The Kruskal-Wallis test followed by the Bonferroni correction for pairwise comparisons was used for statistical analysis (α = 0.05).

Results

Storage time did not influence the VHN of the nano-hybrid composite in any group (p > 0.05). OptiBond XTR Primer application affected the VHN negatively in all investigated storage medium and time conditions (p < 0.05). Modeling Liquid application yielded improved Ra values for the specimens stored in coffee at each time point (p < 0.05). Modeling Liquid application was associated with the lowest ΔE values in all investigated storage medium and time conditions (p < 0.05).

Conclusion

Different types of modeling agents could affect the surface properties and discoloration of nano-hybrid composites.