ABSTRACT
The aim of the present study was to investigate the influence of the mechanical properties of three different calcium-silicate-based cements on the stress distribution of three different retrograde cavity preparations. Biodentine™ "BD", MTA Biorep "BR", and Well-Root™ PT "WR" were used. The compression strengths of ten cylindrical samples of each material were tested. The porosity of each cement was investigated by using micro-computed X-ray tomography. Finite element analysis (FEA) was used to simulate three retrograde conical cavity preparations with an apical diameter of 1 mm (Tip I), 1.4 mm (Tip II), and 1.8 mm (Tip III) after an apical 3 mm resection. BR demonstrated the lowest compression strength values (17.6 ± 5.5 MPa) and porosity percentages (0.57 ± 0.14%) compared to BD (80 ± 17 MPa-1.22 ± 0.31%) and WR (90 ± 22 MPa-1.93 ± 0.12%) (p < 0.05). FEA demonstrated that the larger cavity preparation demonstrated higher stress distribution in the root whereas stiffer cement demonstrated lower stress in the root but higher stress in the material. We can conclude that a respected root end preparation associated with cement with good stiffness could offer optimal endodontic microsurgery. Further studies are needed to define the adapted cavity diameter and cement stiffness in order to have optimal mechanical resistance with less stress distribution in the root.
ABSTRACT
PURPOSE: To evaluate the impact of immediate and delayed zirconia implant placement on crestal bone loss and the clinical outcomes achieved with this approach 1 year after prosthetic loading. Further objectives were to evaluate the influence of age, sex, smoking, implant dimensions, platelet-rich fibrin application and location of the implants in the jawbone on the crestal bone level. MATERIALS AND METHODS: Clinical and radiographic analysis were performed to evaluate the success rates for both groups. The data were analysed statistically through a linear regression analysis. RESULTS: No significant difference was found between immediate and delayed implant placement concerning the amount of crestal bone loss. Sex, age, bone augmentation, diabetes and prosthetic complications did not have a statistically significant influence; only smoking had a negative and statistically significant influence on crestal bone loss (P < 0.05). CONCLUSIONS: Immediate or delayed placement of one-piece zirconia implants may be a good alternative to the use of titanium implants concerning success and survival.
Subject(s)
Bone Diseases, Metabolic , Dental Implants , Humans , Retrospective Studies , Dental Implants/adverse effects , SmokingABSTRACT
The purpose of the present study was to evaluate the physicochemical properties and antibacterial activity of three calcium silicate cements. Mineral trioxide aggregate (MTA Biorep "BR"), Biodentine (BD) and Well-Root PT (WR) materials were investigated using scanning electron microscopy (SEM) at 24, 72 and 168 h of immersion in phosphate buffered saline (PBS). The antibacterial activity against Enterococcus faecalis (E. faecalis), the solubility, roughness, pH changes and water contact angle were also analyzed. All results were statistically analyzed using a one-way analysis of variance test. Statistically significant lower pH was detected for BD than WR and BR (p < 0.05). No statistical difference was found among the three materials for the efficacy of kill against E. faecalis (p > 0.05). Good antibacterial activity was observed (kill 50% of bacteria) after 24 h of contact. The wettability and the roughness of BR were higher than for the other cements (p < 0.05). BD was more soluble than WR and BR (p < 0.05). In conclusion, the use of bioceramic cements as retrograde materials may play an important role in controlling bacterial growth and in the development of calcium phosphate surface layer to support healing. Moreover, the premixed cement was easier to use than powder−liquid cement.
