Khon Kaen University Dental Journal

The Effect of Blood Contamination on Setting Time and Washout Resistance of Three Calcium Silicate Cements

2024-03-22T16:12:56+07:00

The objective of this study was to compare the effect of blood contamination on the setting time and washout resistance of three types of calcium silicate cements including ProRoot MTA, Biodentine, and RetroMTA. Each type was divided into two groups consisting of the blood-contaminated group and the uncontaminated group. The blood-contaminated group, blood was coated inside of the mold and the material was put into the mold. Then, blood was coated on the surface of the material and the specimen was wrapped by the moist gauze. For the blood-uncontaminated group, after putting the material into the mold, it was wrapped by the moist gauze until each material reached initial setting time. Thereafter, the setting time was determined using a universal testing machine until the indenter failed to create a completely circular impression on the surface. In addition, the washout resistance was assessed through metered spray testing, with the subsequent calculation of the percentage of material washed out and analyzed data using two-way ANOVA and post-hoc Sidak test. The results showed that the setting time of all three materials had a significant increase under blood-contaminated conditions. ProRootMTA had the highest setting time which was significantly higher than Biodentine and RetroMTA in both conditions. The washout resistance test demonstrated significant changes in the average washout percentage for all three tested materials under conditions of blood contamination. This study concludes that blood contamination notably increased the setting time across all materials. Regarding washout resistance, a marked difference was observed under both conditions. ProRootMTA exhibited the greatest washout resistance, which diminished upon contamination with blood. In contrast, Biodentine demonstrated the lowest washout resistance in the absence of blood contamination, however the resistance increased when contaminated with blood.

Comparison of Cyclic Fatigue Resistance of M3L-Platinum File with and without Nanoceramic Coating After Sodium Hypochlorite Immersion

2024-04-02T18:29:35+07:00

The purpose of this study was to compare the cyclic fatigue resistance of M3-L Platinum 2018 with M3-L Platinum 2020, which has improved the properties by nanoceramic coating after immersion in sodium hypochlorite. The study was conducted in a simulated root canal using a total of 48 nickel-titanium files divided into 4 groups (n=12) as follows: group 1 M3-L Platinum 2018 without immersion, group 2 M3-L Platinum 2018 immersion in 5.25% NaOCl for 15 minutes, group 3 M3-L Platinum 2020 without immersion, and group 4 M3-L Platinum 2020 immersion in 5.25% NaOCl for 15 minutes. Cyclic fatigue resistance was determined by the number of rotations prior to fracture in a simulated root canal. Data were recorded and analyzed using an Independent t-test at 95% confidence level. The results indicated that M3-L Platinum 2020 in both the immersed and non-immersed groups exhibited statistically significant higher number of cycles to failure than M3-L Platinum 2018. When comparing the mean number of cycles to failure between the same model, whether immersed or not immersed in sodium hypochlorite solution, no statistically significant difference was observed.

The Penetrating Ability of Elastomeric Impression Materials in Simulated Model with Different Sulcular Widths

2024-05-03T16:27:01+07:00

Vinylpolyethersiloxane (VPES) has been developed by combining features of polyether (PE) and polyvinylsiloxane (PVS). Therefore, the study regarding to penetrating ability of this new material in clinically simulated model is scarcely. The purpose of this laboratory study was to evaluate and compare the penetrating ability of VPES, Soft PE, Hydrophilic and Hydrophobic PVS in three different sulcular widths. One hundred forty-four impressions were made from simulated model of sulcular width 0.1, 0.2 and 0.4 mm with four elastomeric impression materials using double-mixed single impression technique. Each impression was sectioned longitudinally then determined the penetrating depth of each specimen by measuring microscope starting from finish line. The data obtained were analyzed by descriptive statistics and two-way ANOVA. There was a statistically significant interaction between the effects of sulcus widths and material types on penetrating ability. VPES and soft PE groups had been shown statistically significant greater penetration than that of PVS groups. While there were no differences between VPES group and soft PE group when sulcus wide 0.4 and 0.2 mm. However, at sulcular width 0.1 mm, VPES was significantly higher penetrating depth than other materials. In conclusions, the penetrating ability of impression materials in wide sulcus was greater than narrow sulcus. VPES had been revealed superior sulcus reproduction in all sulcular widths.

Extraoral Maxillofacial Prosthesis Materials Part I: History and Silicone Elastomer

2024-04-12T22:06:17+07:00

Over time, various materials have been used to create extraoral maxillofacial prostheses. Vulcanized rubber and polyurethane elastomers have certain limitations and are not popular choices for prostheses. In contrast, silicone elastomers are most used due to their softness, flexibility, smoothness, and natural skin-like staining ability. While silicone elastomers are available in various forms, some are specifically designed for maxillofacial prosthesis rehabilitation. However, despite their advantages, silicone elastomer materials have certain limitations and may not always be the best option. Therefore, a thorough study of their properties is essential to fabricate prostheses that offer the best possible outcomes for patients.