1.
Mechanical properties and microstructure analysis of mineral trioxide aggregate mixed with hydrophilic synthetic polymer.
Noh, YS, Chung, SH, Bae, KS, Baek, SH, Kum, KY, Lee, WC, Shon, WJ, Rhee, SH
Journal of biomedical materials research. Part B, Applied biomaterials. 2015;(4):777-82
Abstract
INTRODUCTION In dentistry, mineral trioxide aggregate (MTA) has been widely used for root perforation, retrograde filling, pulp capping and regenerative endodontics. Despite its superior sealing ability and biocompatibility, MTA has critical drawbacks regarding handling property such as sandy property, lacking cohesive properties and wash-out tendency. So, it is necessary to improve the fluidity of MTA in order to improve its handling properties. In this study, we applied modified liquid to improve handling properties of MTA. METHODS Polyvinyl alcohol (PVA; 3 and 5 wt %) aqueous solutions were prepared and the samples were divided into three groups: DW group (MTA mixed with distilled water), P3 group (MTA mixed with 3% PVA), and P5 group (MTA mixed with 5% PVA). Handling property, initial setting time, and compressive strength were evaluated. The microstructures were observed by Field emission scanning electron microscope (FE-SEM) and X-ray diffractometer (XRD) phase analyses were performed. RESULTS PVA modified group showed similar behavior of IRM compared to DW group. The initial setting time of P3 or P5 group was significantly longer than that of DW group (p < 0.05). The compressive strength of DW group was higher than that of P3 or P5 groups (p < 0.05). Experimental groups (P3 and P5) showed no microstructural differences compared with DW group when the fractured surfaces were observed by FE-SEM with XRD patterns after 3 and 14 days. CONCLUSIONS Polyvinyl alcohol, a modified liquid for MTA, improved the handling properties of the material without violating its microstructure.
2.
Effects of calcium phosphate endodontic sealers on the behavior of human periodontal ligament fibroblasts and MG63 osteoblast-like cells.
Shon, WJ, Bae, KS, Baek, SH, Kum, KY, Han, AR, Lee, WC
Journal of biomedical materials research. Part B, Applied biomaterials. 2012;(8):2141-7
Abstract
In regard to biological properties of endodontic sealers, there are many characteristics that should be considered. The aim of this study was to examine the biological effects of new calcium phosphate-based root canal sealers, CAPSEAL I and CAPSEAL II (CPS), on human periodontal fibroblast cells by examining the expression levels of inflammatory mediators and to compare the effects of CPS on the viability and osteogenic potential of human osteoblast MG63 cells compared to those of other commercially available calcium phosphate sealers [Apatite Root Sealer type I (ARS I) and Apatite Root Sealer III (ARS III); Sankin Kogyo, Tokyo, Japan] and a zinc oxide eugenol-based sealer (Pulp Canal Sealer EWT [PCS EWT]; Kerr, Detroit, MI). The levels of IL-6 in the new CPS group (CAPSEAL I, II) were higher than those in the control and all experimental groups at all time points after 2 h. TGF-β1 and FGF-1 levels decreased at 72 h compared to the levels in the control, in cells treated with every sealers except ARS I. The new CPS sealers showed low cytotoxicity. Reverse transcription polymerase chain reaction showed that CAPSEAL I, II, and Apatite Root Sealer type III induced expression of early stage markers of differentiation (alkaline phosphatase and osteopontin) at 7 days. Also, new CPS showed higher mineralized nodule formation at 28 days. These results suggest that CAPSEAL I and II facilitate the periapical dentoalveolar and alveolar healing by controlling cellular mediators from PDL cells and osteoblast differentiation of precursor cells.