RESUMO
BACKGROUND: The aim of this study was to calculate the stress distribution of fiberglass post associated with resin composite crown restoration and fiberglass posts with zirconia restorations in mature and immature endodontically treated central maxillary incisor under various loading conditions. MATERIALS AND METHODS: The study created six different study models in a virtual environment: healthy mature maxillary central teeth, intact immature maxillary central teeth, mature maxillary central teeth with fiberglass post associated with resin composite crown restoration, immature maxillary central teeth with fiberglass post associated with resin composite crown restoration, mature maxillary central teeth with fiberglass posts and zirconia restoration, and immature maxillary central teeth with fiberglass posts and zirconia restoration. Loading conditions simulating mastication, trauma, and bruxism were applied to each of the models at different angles and amounts. The von Mises and the maximum and minimum principal stress values in tooth structures (dentin) and support structures (bone, PDL) and materials were observed using finite element stress analysis. RESULTS: The highest stress values in the tissue and the restoration structure were observed for masticating force and crowns rehabilitated with zirconia restorations. None of the compared loading conditions and restorations showed destructive stress values on periodontal ligament or bone. CONCLUSION: The mature and immature endodontically treated central maxillary incisors can be better rehabilitated using fiberglass post associated with resin composite crown restoration and may be preferred to zirconia restorations in order to reduce the stresses on the surrounding tissues and teeth. However, further clinical studies are needed to fully explore this topic.
RESUMO
OBJECTIVES: The present study aimed to (1) investigate biocompatibility and cytotoxicity of pulp-capping materials on viability of human dental pulp stem cells (hDPSCs); (2) determine angiogenic, odontogenic, and osteogenic marker mRNA expressions; and (3) observe changes in surface morphology of the hDPSCs using scanning electron microscopy (SEM). METHODS: Impacted third molars were used to isolate the hDPSCs, which were treated with extract-release fluids of the pulp-capping materials (Harvard BioCal-Cap, NeoPUTTY MTA, TheraCal LC, and Dycal). Effects of the capping materials on cell viability were assessed using 3-(4,5-di-methyl-thiazol-2-yl)-5-(3-carboxy-methoxy-phenyl)-2-(4-sulfo-phenyl)-2H-tetrazolium (MTS) assay and the apoptotic/necrotic cell ratios and reactive oxygen species (ROS) levels from flow cytometry. Marker expressions (alkaline phosphatase [ALP], osteocalcin [OCN], collagen type I alpha 1 [Col1A], secreted protein acidic and rich in cysteine [SPARC], osteonectin [ON], and vascular endothelial growth factor [VEGF]) were determined by quantitative reverse-transcription polymerase chain reaction. Changes in surface morphology of the hDPSCs were visualised by SEM. RESULTS: The MTS assay results at days 1, 3, 5, and 7 indicated that Harvard BioCal-Cap, NeoPUTTY MTA, and TheraCal LC did not adversely affect cell viability when compared with the control group. According to the MTS assay results at day 14, no significant difference was found amongst Dycal, Harvard BioCal-Cap, NeoPUTTY MTA, and TheraCal LC affecting cell viability. Dycal was the only capping material that increased ROS level. High levels of VEGF expression were observed with Harvard BioCal-Cap, TheraCal LC, and NeoPUTTY MTA. NeoPUTTY MTA, and Dycal upregulated OCN expression, whereas TheraCal LC upregulated Col1A and SPARC expression. Only Dycal increased ALP expression. HDSCs were visualized in characteristic spindle morphology on SEM when treated with TheraCal LC and Harvard BioCal-Cap. CONCLUSIONS: NeoPUTTY MTA and Harvard BioCal-Cap showed suitable biocompatibility values; in particular, these pulp-capping materials were observed to support the angiogenic marker.