MATERIALS AND METHODS: To prepare a total of 90 acrylic resin samples (45 acrylic resin samples for each material), four rectangular stainless-steel plates measuring 25 × 25 × 10 mm were fabricated. For both groups, the material was put into the mold at the dough stage. Group I - SR Triplex Hot Heat Cure acrylic; group II - DPI Heat Cure acrylic. Both groups used the same curing procedure. One of the following three techniques was used to cool the material (15 samples from each material) once the curing cycle was finished: (A) water bath, (b) quenching, and (C) air. A traveling microscope was used to measure the distance between the markings on the acrylic samples. The data was recorded and statistically analyzed.
RESULTS: In SR Triplex Hot heat cure acrylic material, the maximum linear dimensional changes were found in the quenching technique (0.242 ± 0.05), followed by the air technique (0.168 ± 0.11) and the least was found in the water bath technique (0.146 ± 0.01). In DPI Heat Cure acrylic material, the maximum linear dimensional changes were found in the quenching technique (0.284 ± 0.09), followed by the air technique (0.172 ± 0.18) and the least was found in the water bath technique (0.158 ± 0.10). There was a statistically significant difference found between these three cooling techniques. On comparison of adaptability, the water bath technique, the marginal gap SR Triplex Hot was 0.012 ± 0.02 and DPI Heat Cure was 0.013 ± 0.02. In the quenching technique, the marginal gap SR Triplex Hot was 0.019 ± 0.04 and DPI Heat Cure was 0.016 ± 0.04. In the air technique, the marginal gap SR Triplex Hot was 0.017 ± 0.01 and DPI Heat Cure was 0.019 ± 0.01.
CONCLUSION: The present study concluded that among the different cooling methods, the water bath technique had the least linear dimensional change, followed by the air and quenching techniques. When comparing the materials, DPI Heat Cure acrylic resin showed a greater linear dimensional change than SR Triplex Hot heat cure acrylic resin.
CLINICAL SIGNIFICANCE: During polymerization, heat-cured acrylic resins experience dimensional changes. Shrinkage and expansion are dimensional changes that occur in heat-cured acrylic resins and have an impact on the occlusal relationship and denture fit. However, the denture base's material qualities and the different temperature variations it experiences during production may have an impact on this. How to cite this article: Kannaiyan K, Rathod A, Bhushan P, et al. Assessment of Adaptability and Linear Dimensional Changes of Two Heat Cure Denture Base Resin with Different Cooling Techniques: An In Vitro Study. J Contemp Dent Pract 2024;25(3):241-244.
MATERIAL AND METHOD: Forty sound permanent mandibular premolars were collected from a dental clinical setting and disinfected. All forty samples were mounted vertically in a rubber mold exposing only the clinical crown. All samples were bleached using Opalescence Boost Professional Teeth Whitening. After the bleaching procedure, each sample was randomly allocated into four groups according to surface treatment. Samples in group 1 were treated with methylene blue photosensitizer (MBP). Samples in group 2 were exposed to 10% sodium ascorbate. Samples in group 3 were treated with Er, Cr: YSGG laser (ECL). Samples in group 4 were not treated (control). All Samples were treated with 37% phosphoric acid and a bonding agent was applied. A bulk-fill composite was cured to all specimens and all samples were treated in a thermocycler. Specimens were placed in a universal testing machine for shear bond strength (SBS) testing. Descriptive statistics were associated by analysis of variance (ANOVA) and Tukey's post hoc test maintaining level of significance (p<0.05) RESULTS: The lowest SBS scores were achieved in the bleached enamel (BE) group (15.25±1.745 MPa). Whereas, the highest bond integrity was attained by AA group (32.23±1.854 MPa). Samples treated with ECL (31.87±1.659 MPa) and AA (32.23±1.854) were comparable (p>0.05). Samples treated with PDT exhibited significantly different SBS (22.41±1.258) compared to other experimental groups CONCLUSION: ECL showed a reversal effect of BE compared to AA and has the potential to be used in clinical settings. BE reversal using MBP needs further investigation.