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.
OBJECTIVES: The aim of this study was to compare the biaxial flexural strength of three core ceramic materials.
MATERIAL AND METHODS: Three groups of 10 disc-shaped specimens (16 mm diameter x 1.2 mm thickness - in accordance with ISO-6872, 1995) were made from the following ceramic materials: Turkom-Cera Fused Alumina [(Turkom-Ceramic (M) Sdn Bhd, Puchong, Selangor, Malaysia)], In-Ceram (Vita Zahnfabrik, Bad Säckingen, Baden-Württemberg, Germany) and Vitadur-N (Vita Zahnfabrik, Bad Säckingen, Baden-Württemberg, Germany), which were sintered according to the manufacturer's recommendations. The specimens were subjected to biaxial flexural strength test in an universal testing machine at a crosshead speed of 0.5 mm/min. The definitive fracture load was recorded for each specimen and the biaxial flexural strength was calculated from an equation in accordance with ISO-6872.
RESULTS: The mean biaxial flexural strength values were: Turkom-Cera: 506.8 ± 87.01 MPa, In-Ceram: 347.4 ± 28.83 MPa and Vitadur-N: 128.7 ± 12.72 MPa. The results were analyzed by the Levene's test and Dunnett's T3 post-hoc test (SPSS software V11.5.0 for Windows, SPSS, Chicago, IL, USA ) at a preset significance level of 5% because of unequal group variances (P<0.001). There was statistically significant difference between the three core ceramics (P<0.05). Turkom-Cera showed the highest biaxial flexural strength, followed by In-Ceram and Vitadur-N.
CONCLUSIONS: Turkom-Cera core had significantly higher flexural strength than In-Ceram and Vitadur-N ceramic core materials.