Evaluation Of The Transverse Strength Of Denture Base Resins Repaired With Conventional Heat Cure Or Autopolymerising Resins Under Different Surface Treatments- An In Vitro Study
Evaluation Of The Transverse Strength Of Denture Base Resins
Keywords:
acrylic resin, chemical surface treatment, flexural strength, heat cure resin, mechanical surface treatment, repair materials, self cure resin, strength, surface treatments, transverse strengthAbstract
Aim: Acrylic resin dentures are susceptible to fracture after clinical use. The denture repair should be easy, strong and should not affect the dimensional accurac. Objective: The study was conducted with an objective of evaluating the transverse strength of two types of heat cure resins when repaired with different types of heat cure and autopolymerizing acrylic resins under different surface treatments. Methods: 195 rectangular specimens (65.0 x 10.0 x 3.3mm) of DPI-Heat Cure and Acralyn H were fabricated according to ADA Specification No.12, and stored in distilled water at room temperature for 7 days. 15 specimens of each material remained intact (control). 180 specimens of each material were sectioned in the middle to create a 10mm gap. 60 specimens each were treated with different surface treatments like wetting with methylmethacrylate monomer for 180sec and air borne particle abrasion for 5sec and 60 specimens were repaired without any surface treatment. Among these 60 specimens, 15 each were repaired with materials DPI-Heat Cure, Acralyn H, DPI-RR and Acralyn R. After an additional 7 days of storage at room temperature, the transverse strength of intact and repaired specimens was measured using a 3 point bending test in Universal Testing Machine. The nature of failure was noted as adhesive, cohesive or mixed. The data obtained was subjected to statistical analysis. The mean and standard deviation were calculated for each group. Result: The intact DPI- heat cure specimens had higher strength than Acralyn H. When repaired with heat cure repair resins the strength was higher compared to autopolymerizing resins. Repaired specimens exhibited 3 types of failure; adhesive, cohesive and mixed, with an incidence of 15.6%, 25% and 59.4% respectively. Adhesive failure was commonly seen with no surface treatment. Cohesive type of failure was increased with chemical and mechanical surface treatments. Conclusion: As heat polymerising resins have better strength and the properties than autopolymerising resins, it should more often be used as repair material. [Sankeshwari B NJIRM 2017; 8(1): 60-65]
References
2. Ana MC, Carlos EV, Eunice TG, Maria FA. Water sorption, solubility and bond strength of two autopolymerising acrylic resins and one heat polymerising acrylic resin. J Prosthet Dent 1998; 80: 434-8.
3. Minami H, Suzuki S, Minesaki Y, Kurashige H, Tanaka T. In vitro evaluation of the influence of repairing condition of denture base resin on the bonding of auto polymerizing resins. J Prosthet Dent 2004; 91:164-70.
4. Sarac SY, Sarac D, Kulunk T, Kulunk S. The effect of chemical surface treatment of different denture base resins on the shear bond strength of denture repair. J Prosthet Dent 2005; 94: 259-66.
5. Nogueira SS, Ogle RE, Davis EL. Comparison of accuracy between compression- and injection-molded complete dentures. J Prosthet Dent 1999; 82: 291-300.
6. Tan LH, Chew BS, Thean HP. Shear bond strength of microwaveable acrylic resin for denture repair. J Oral Rehabil 2004; 31: 798-802.
7. Beyli MS, Dent MD, Fraunhofer JA. An analysis of cause of fracture of acrylic resin dentures. J Prosthet Dent 1981; 46:238-240.
8. Rosangela SS, Karin HN, Joao AH. Factors affecting the strength of denture repairs. J Prosthodont; 2007: 16: 302-310.
9. Stipho HD, Stipho AS. Effectiveness and durability of repaired acrylic resin joints. J Prosthet Dent 1987; 58:249-252.
10. William MH, Bruce ES. The effect of joint surface contours on the transverse strength of repaired acrylic resin. J Prosthet Dent 1970; 23:464-470.
11. John WS, Claire LB, George CP. Self curing resins for repairing dentures: Some physical properties. J Am Dent Asssoc 1955; 57:307-315.
12. Eiichi N, Kenji O, Yoshinori S, Shiro S. Repair of denture base resin using woven metal and glass fiber: Effect of methylene chloride pretreatment. J Prosthet Dent 2001; 85: 496-500.
