PURPOSEThe aim of this in-vitro investigation was to describe the effect of reinforcement with different fibers on impact strength of heat polymerized polymethyl methacrylate (PMMA) denture base resin and to analyze the effect of surface treatment of the fibers on the impact strength.MATERIALS AND METHODSThe specimens were fabricated from the dies formed as per standard ASTM D4812. 2% by weight of glass, polyethylene and polypropylene fibers were incorporated in the PMMA resin. The Izod impact testing was performed on the unnotched specimens and the values obtained were analyzed using appropriate one way ANOVA, followed by unpaired t-test. Fractured ends of the samples were subjected to the SEM analysis.RESULTSThe polypropylene fibers with plasma treatment showed the highest impact strength (9.229 × 102 J/m) followed by the plasma treated polyethylene fibers (9.096 × 102 J/m), untreated polypropylene fibers (8.697 × 102 J/m), untreated polyethylene fibers (7.580 × 102 J/m), silane treated glass fibers (6.448 × 102 J/m) and untreated glass fibers (5.764 × 102 J/m). Also the surface treatment of all the fibers has shown the significant improvement in impact strength. Findings of the SEM analysis justified the improvement in impact strength after surface treatment.CONCLUSIONReinforcement with the fiber is an effective method to increase the impact strength of PMMA denture base resin. The surface treatment of fibers further increases the impact strength significantly.

As a result, the primary surgical repair of the lip and nose heals under minimal tension, thereby reducing scar formation and improving the esthetic result. Frequent surgical intervention to achieve the desired esthetic results can be avoided by PNAM.

PURPOSEThe aim of this study was to compare the flexural strength of polymethyl methacrylate (PMMA) and bis-acryl composite resin reinforced with polyethylene and glass fibers.MATERIALS AND METHODSThree groups of rectangular test specimens (n = 15) of each of the two resin/fiber reinforcement were prepared for flexural strength test and unreinforced group served as the control. Specimens were loaded in a universal testing machine until fracture. The mean flexural strengths (MPa) was compared by one way ANOVA test, followed by Scheffe analysis, using a significance level of 0.05. Flexural strength between fiber-reinforced resin groups were compared by independent samples t-test.RESULTSFor control groups, the flexural strength for PMMA (215.53 MPa) was significantly lower than for bis-acryl composite resin (240.09 MPa). Glass fiber reinforcement produced significantly higher flexural strength for both PMMA (267.01 MPa) and bis-acryl composite resin (305.65 MPa), but the polyethylene fibers showed no significant difference (PMMA resin-218.55 MPa and bis-acryl composite resin-241.66 MPa). Among the reinforced groups, silane impregnated glass fibers showed highest flexural strength for bis-acryl composite resin (305.65 MPa).CONCLUSIONOf two fiber reinforcement methods evaluated, glass fiber reinforcement for the PMMA resin and bis-acryl composite resin materials produced highest flexural strength.Clinical implicationsOn the basis of this in-vitro study, the use of glass and polyethylene fibers may be an effective way to reinforce provisional restorative resins. When esthetics and space are of concern, glass fiber seems to be the most appropriate method for reinforcing provisional restorative resins.

On the basis of this in--vitro study, the use of Glass and Polyethylene fibers tested may be an effective way to reinforce resins used to fabricate fixed provisional restorations.

No abstract