ABSTRACT
The aim of this study was to evaluate the mechanical properties of polymethyl methacrylate (PMMA) after coating with different ceromers. For transverse strength and modulus of elasticity tests, specimens of 65×10×2.5 mm dimensions were prepared (5 groups, n=10). For impact strength test, specimens of 60×7.5×4 mm dimensions were prepared (5 groups, n=10). Test group specimens were coated with one of four different types of ceromers, and specimens in the control group were not coated. After specimens were tested for transverse and impact strengths, the data were analyzed with Kruskal-Wallis and Conover post hoc tests (p<0.05). GLYMOTEOS-TiO2 and A174-TEOS significantly increased the transverse strength of PMMA. All ceromers caused a statistically significant increase in the elastic modulus of PMMA. While GLYMO-TEOS-ZrO2 significantly decreased the impact strength, the other ceromers did not cause any statistically significant difference in impact strength. Coating with ceromers substantially improved the mechanical properties of PMMA.
Subject(s)
Ceramics/chemistry , Coated Materials, Biocompatible/chemistry , Composite Resins/chemistry , Denture Bases , Elastic Modulus , Polymethyl Methacrylate/chemistry , Silanes/chemistry , Dental Stress Analysis , Materials Testing , Stress, Mechanical , Surface PropertiesABSTRACT
Due to the possible aesthetic problems of titanium implants, the developments in ceramic implant materials are increasing. Natural tooth colored ceramic implants may be an alternative to overcome aesthetic problems. The purpose of this article is to give information about the basic properties of dental zirconia implants and present 3 cases treated with two-piece zirconia implants. Two-piece zirconia dental implants, 4.0 mm diameter and 11.5 mm in length, were inserted into maxillary incisor region. They were left for 6 months to osseointegrate. Panoramic and periapical radiographs were obtained and examined for bone-implant osseointegration. During the follow-up period the patients were satisfied with their prosthesis and no complication was observed.
Subject(s)
Dental Implants , Dental Materials/chemistry , Yttrium/chemistry , Zirconium/chemistry , Adult , Esthetics, Dental , Female , Follow-Up Studies , Humans , Incisor/injuries , Male , Maxilla/surgery , Osseointegration/physiology , Patient Satisfaction , Tooth Extraction , Tooth Fractures/surgery , Tooth Socket/surgery , Tooth, Nonvital/surgery , Young AdultABSTRACT
PURPOSE: The aim of the present study was to evaluate the effect of the forces on the implant and supporting alveolar ridge in "all on four" concept and alternative designs using finite element analysis. MATERIALS AND METHODS: Different treatment alternatives with various implant designs were performed in an edentulous mandible. In Design 1, implants were placed according to "All-on-Four" concept; Design 2, two long (13 mm long, 4 mm diameter) and two short (7 mm long, 4 mm diameter) implants; Design 3, four long and two short implants; and Design 4, two long and four short implants were placed vertically. A force of 100 N for each tooth, a total of 300 N load was applied. Finite element analysis was used to evaluate and compare the different designs. RESULTS: The stress concentration within the cortical bone was significantly higher than the trabecular bone around the neck of the implants. The maximum stress values were located around the cortical bone of the distal implant for all designs. The reduction in the number of implants did not diminish the success of the design. CONCLUSIONS: In the presence of vertically resorbed posterior mandibula, although the "all on four" concept is a feasible approach clinically, short implants had decreased the amount of force transmitted to the supporting bone.
Subject(s)
Dental Implantation, Endosseous/methods , Dental Implants , Dental Prosthesis Design , Finite Element Analysis , Imaging, Three-Dimensional , Mandible/diagnostic imaging , Tomography, X-Ray Computed , Alveolar Process/pathology , Biomechanical Phenomena , Dental Stress Analysis , Elastic Modulus , Humans , Jaw, Edentulous/rehabilitation , Mandible/surgery , Radiographic Image Interpretation, Computer-Assisted , SoftwareABSTRACT
PURPOSE: The purpose of this study was to measure spectrophotometrically the color changes of pigmented maxillofacial silicone elastomers with different pigments and pigmenting methods after storing 1 year in the dark environment. METHODS: Three maxillofacial silicones, Cosmesil M511 (CosM511), Cosmesil M522 (CosM522), and Multisil-Epithetic (Mult-Epit), were selected for this study. A total of 240 specimens were fabricated; 80 of each of the 3 elastomers (n = 5) (18 mm in diameter and 2 mm in thickness) were prepared in 6 colorant categories (5 colorant and 1 with no colorant). Specimens were stored in a black box representing a condition of total darkness and placed in a dark environment at ambient room temperature (22°C ± 10°C) and humidity (50% ± 10%) for 1 year. A color spectrophotometer was used to measure the ΔE* values of the test specimens to determine the color changes. RESULTS: The lowest color changes were observed in CosM511 in white color (ΔE* = 1.31) and in Mult-Epit in white color (ΔE* = 1.82) in extrinsic coloration group. The highest color changes were observed in yellow color in CosM511 (ΔE*= 21.61) and CosM522 (ΔE*= 23.78) in silicone pigmented intrinsic coloration method. In coloration methods, intrinsic silicone pigmented groups in all colors except brown in Mult-Epit had the highest ΔE* values. CONCLUSIONS: Significant color changes were observed in both pigmented and unpigmented specimens, which were stored in dark environment and not exposed to sunlight.
