An in vitro comparison of different adhesive strategies on the micro push-out bond strength of a glass fiber post

Objectives: To evaluate in vitro the push-out bond strengths of a glass fiber post adhesively luted with self-etching resin based and self-adhesive luting cements, as well as modified application procedure of self-adhesive luting cements in combination with single step self-etch adhesives. Materials and methods: Fifty single-rooted human maxillary central incisor teeth were endodontically treated and divided into five groups (n=10). Glass fiber posts (RelyX Fiber Post) were cemented with the following materials: group 1: ED Primer II/Panavia F 2.0 (PAN); group 2: RelyX Unicem (RU); group 3: Maxcem (MC); group 4: Adper Prompt L-Pop (PLP)/RelyX Unicem; group 5: Optibond all-in-one (OB)/Maxcem. Bonded specimens were cut (1-mm-thick sections) and push-out tests were performed (crosshead-speed, 0.5 mm/min). Data were analyzed by one-way ANOVA followed by the Tukey-HSD test for post hoc comparisons at ? = 0.05. Results: The highest bond strength was recorded for groups 4 and 2, with no statistically significant differences among them (p>0.05). Group 4 showed significantly higher bond strength than group 1 (p<0.001), group 3 (p<0.0001) and group 5 (p<0.0001). Group 1 showed significantly higher bond strength than the group 3 (p<0.05). No statistically significant differences were observed among group 1 and group 2, group 1 and group 5, group 3 and group 5. Group 3 showed significantly lower push-out bond strength than the all other luting strategies except for the group 5. Conclusions: The push-out bond strength values of modified application procedure of self-adhesive luting cements (RU and MC) in combination with single step self-etch dentin adhesives (PLP and OB) did not improve the push-out bond strength of fiber post when compared with those where the conventional use of self-adhesive cements. © Medicina Oral S. L

The cytotoxic evaluation of mineral trioxide aggregate and bioaggregate in the subcutaneous connective tissue of rats

Objectives: The purpose of this study was to evaluate and compare the cytotoxic effects of ProRoot MTA and DiaRoot BA, a bioceramic nanoparticulate cement, on subcutaneous rat tissue. Study D esign: Fifty Sprouge Dawley rats were used in this study. Polyethylene tubes filled with ProRoot MTA and DiaRoot BioAggregate, along with a control group of empty, were implanted into dorsal connective tissue of rats for 7, 15, 30, 60, and 90 days. After estimated time intervals the rats were sacrificed. The specimens were fixed, stained with hematoxylin and eosin, and then evaluated under a light microscope for inflammatory reactions and mineralization. Results: All groups evoked a severe to moderate chronic inflammatory reaction at 7 and 15 days, which decreased with time. Both the MTA and BioAggregate groups showed similar inflammatory reactions, except at 90 days when MTA showed statistically significant greater inflammation (p>0.05). The MTA group showed foreign body reaction at all times. Compared to BioAggregate, MTA showed significantly more foreign body reaction at 60 and 90 days (p<0.0001). After 30 days foreign body reaction of BioAggregate decreased significantly. Both MTA and BioAggregate groups showed similar necrosis at 7 and 15 days (p=0.094 and p=0.186 respectively). No necrosis was observed after 15 days. Similarly there was no fibrosis after 30 days for both MTA and BioAggregate groups (p>0.05). Conclusions: Since DiaRoot BioAggregate showed significantly better results than MTA, we can conclude that it is more biocompatible. However, further studies are required to confirm this result

DENTIN BONDING SYSTEMS AND HYBRIDIZATION

Recently, with the development of adhesive dentistry, multistep dentin bonding to dental tissues was modified to simplified and more user friendly adhesive systems. The mechanism of adhesion is based on the mechanical interlocking within the formation of hybrid layer. Hibrization quality is effected by the type of the adhesive system, dental tissue, application method, materials consistence and physical and chemical properties. The aim of this review is to evaluate the hybridization quality of current adhesive systems