Objective: Reinforcement with fiber is an effective method for considerable improvement in flexural properties of indirect composite resin restorations. The aim of this in-vitro study was to compare the TRANSVERSE STRENGTH of composite resin bars reinforced with pre-impregnated and non-impregnated fibers.Materials and Methods: Thirty six bar type composite resin specimens (3×2×25 mm) were constructed in three groups. The first group was the control group (C) without any fiber reinforcement. The specimens in the second group (P) were reinforced with pre-impregnated fibers and the third group (N) with non-impregnated fibers. These specimens were tested by the three-point bending method to measure primary TRANSVERSE STRENGTH. Data were statistically analyzed with one way ANOVA and Tukey’s tests.Results: There was a significant difference among the mean primary TRANSVERSE STRENGTH in the three groups (P<0.001). The post-hoc (Tukey) test showed that there was a significant difference between the pre-impregnated and control groups in their primary TRANSVERSE STRENGTH (P<0.001). Regarding deflection, there was also a significant difference among the three groups (P=0.001). There were significant differences among the mean deflection of the control group and two other groups (PC&N<.001 and PC&P=.004), but there was no significant difference between the non- and pre-impregnated groups (PN&P=.813).Conclusion: Within the limitations of this study, it was concluded that reinforcement with fiber considerably increased the TRANSVERSE STRENGTH of composite resin specimens, but impregnation of the fiber used implemented no significant difference in the TRANSVERSE STRENGTH of composite resin samples.

In the present study, a new model is derived to estimate the shear capacity of high-STRENGTH concrete slender beams without TRANSVERSE reinforcement using hybrid adaptive neuro-fuzzy inference system (ANFIS) and particle swarm optimization (PSO) based on the wide range of experimental results. The proposed model relates the shear capacity of beam to effective depth, compressive STRENGTH of concrete, percent of longitudinal reinforcement, ratio of shear span to effective depth, and nominal maximum size of coarse aggregate. The experimental data are randomly categorized into two subsets of the training set and test set. After establishing the proposed model, a sensitivity analysis was carried out to assess the validity of proposed ANFIS-PSO model. For this purpose, the results of the proposed model are calculated by considering the variation of the two selected input parameters, whereas the values of other parameters are fixed at the corresponding median values. To check reliability of the proposed model more accurately, the predicted values are compared with the codes and standards such as: ACI 318-14, Eurocode-2, CEB-FIP Model Code, AS 3600-2009, and JSCE Guidelines against the whole experimental specimens based on the three well-known statistical measures,correlation coefficient (R^2), root mean squared error (RMSE), and mean absolute percentage error (MAPE). It can be found that the proposed ANFIS-PSO model passed desired conditions and could estimate the shear capacity of the high-STRENGTH concrete slender beams without TRANSVERSE reinforcement with a good degree of accuracy.

Introduction: High fracture resistance of prostheses are well accepted by both patients and dentists to have a proper restoration of the dentition. The research designated assess polymerization time effect distinct and complete temperatures on mechanical properties (denture base resin) of a high STRENGTH. The research purpose is to assess and compare the procedure used in polymerization distinct effect autoclave on the elastic modulus and TRANSVERSE STRENGTH of a high STRENGTH acrylic resin to the conventional heat polymerizing. Methods: Rectangular sample of ninety-one polymarised high heat STRENGTH denture base resin were created. Polymerized sample done by hot water regarded as control group and the other groups were polymerized in autoclave at different temperatures and time lenghts. After deflasking of sample before procedure it was kept forty eight hours in water. Three parameters were used when conducting TRANSVERSE STRENGTH test bending using calibrated universal testing machine with a load of 500 kg cell and a crosshead speed of 5 mm/min. One-way ANOVA was used in assessing TRANSVERSE STRENGTH and elastic modulus data. And for comparison of the groups application of Tukey HSD trial has been seen appropriate (p<0. 05). Results: Specimens that polymerized by autoclave at 130º C for 20 and 30 minutes showed significantly better characteristics compared to the other groups. Conclusion: Upgrading of base resins TRANSVERSE STRENGTH is required because the research indicated autoclave polymerization at 130° C for 20 and 30 minutes may be an alternative polymerization method.

Statement of problem: Fracture STRENGTH of a denture base resin is of great concern, and many approaches have been used to STRENGTHen acrylic resin dentures. Purpose: The aim of this study was to measure the TRANSVERSE STRENGTH of a heat polymerized acrylic resin, after reinforcement with metal wire and two types of glass fibers. Materials and Methods: Forty rectangular specimens (65.0×10.0×3.3 mm) of a heatcured acrylic resin were made according to ISO/FDI 1567. Group I (control group) consisted of 10 specimens with no reinforcement. Specimens in group II reinforced with sandblasted metal wires. Group III and IV STRENGTHened with woven (Stick Net) and continuous unidirectional (Stick) fibers respectively. The specimens were polymerized according to manufacturer's recommendation. The TRANSVERSE STRENGTHs were assessed with a 3- point bending test at cross head speed of 5mm/min. One-way ANOVA was carried out to compare and detect any differences among groups (a=0.05). Results: Mean TRANSVERSE STRENGTH (SD) of unreinforced specimens was 85.44 (8.6) MPa. The TRANSVERSE STRENGTH increased significantly to 97.97 (5.5) MPa, 109.69 (5.8) MPa, and 127.13 (6.4) MPa in Metal wires, Stick Net, and stick fibers groups, respectively.Conclusion: The TRANSVERSE STRENGTH of heat-polymerized denture base resin was enhanced considerably by using metal wire and glass fibers reinforcements. However, the addition of unidirectional glass fibers was significantly more effective method to improve flexural STRENGTH of denture base acrylic resin.

Objective: The purpose of this study was to evaluate the TRANSVERSE STRENGTH of one brand of denture base material repaired with two autopolymerized acrylic resins with and without wire reinforcement.Materials and Methods: Eighty samples (2.5×10×65 mm3) were fabricated and divided into five groups. The control group was left intact. Groups B and D specimens were repaired with autopolymerizing acrylic resins. Groups A and C specimens were repaired with metal wire and autopolymerizing acrylic resins. After 48 hours of storage at 37oC, the TRANSVERSE STRENGTH of the specimens was measured with a universal testing machine. Data were analyzed by one way ANOVA and Duncan test (a=0.05).Results: Significant differences were found between the control group and the other experimental groups (P<0.05). Among experimental groups, group D showed the highest TRANSVERSE STRENGTH with the mean value of 40.2 (SD=11.8) MPa while group B present the lowest TRANSVERSE STRENGTH of 28.4 (SD=5.4) MPa. The difference between the TRANSVERSE STRENGTH of group D and the other groups was statistically significant (P<0.05).Conclusion: In wire reinforced groups, there was no significant difference between two types of acrylic resin (P=0.93), however in repaired groups without wire, the type of acrylic resin generates a significant difference in the TRANSVERSE STRENGTH of the repaired specimens (P<0.05). The application of wire significantly reduces the TRANSVERSE STRENGTH of the Meliodent repaired groups (P<0.05), however the changes occurred in TRANSVERSE STRENGTH of the Acropars repaired groups was not statistically significant (P=0.28).