Statement Of Problem: It is known that drying dental stones in a microwave oven can save time, but the strength of the material may be affected by different drying methods.
Purpose: This study evaluated the diametral tensile strength (DTS) of 5 type IV gypsum products at different time intervals using microwave and air-drying methods.
Material And Method: . A total of 300 cylinder specimens were prepared from 5 type IV dental stones (Moldano, Amberok, Herastone, Shera-Sockel, and Fujirock; n = 60 per stone) in accordance with the manufacturers' recommendations. Half of the specimens of each stone (n = 30) were dried in open air within a temperature range of 20 +/- 2 degrees C; the other half (n = 30) underwent initial setting in a silicone rubber mold in open air for 10 minutes and then were dried in a microwave oven for 10 minutes. Within these groups, 10 specimens were tested under diametral compression at each of the following time periods: 30, 60, and 120 minutes after drying. Three-way analysis of variance and Scheffe's post hoc test were performed for statistical comparisons at a significance level of P<.05.
Results: At all time intervals, the diametral tensile strength values for dental stones dried in a microwave oven (mean 2.99 MPa) were significantly higher (P<.01) than the values for specimens dried in open air (mean 2.53 MPa).
Conclusion: Within the limitations of this study, microwave oven drying had a positive effect on the diametral tensile strength of 5 type IV dental stones.
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http://dx.doi.org/10.1067/mpr.2002.124095 | DOI Listing |
J Indian Prosthodont Soc
January 2025
Department of Prosthodontics, Chhattisgarh Dental College and Hospital, Rajnandgaon, Chhattishgarh, India.
Aim: The aim of this study was to compare the marginal accuracy of polyetheretherketone (PEEK) and zirconia copings fabricated using computer-aided design/computer-aided manufacturing (CAD/CAM) technology, and to assess the impact of their material properties on accuracy when produced with a 4-axis milling system under controlled conditions.
Settings And Design: The study employed an in vitro design with a stainless steel die model featuring a 6 mm axial wall height, a 6-degree total occlusal convergence, and a radial shoulder finish line.
Materials And Methods: Thirty stone dies were created from silicone impressions of the metal die and poured using type-IV dental stone.
Oral Dis
January 2025
Department of Oral and Maxillofacial Radiology, Peking University School and Hospital of Stomatology & National Center of Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health & NMPA Key Laboratory for Dental Materials, Beijing, China.
Objective: To investigate the microarchitecture and crystalline composition of sialoliths and to explore their formation mechanisms.
Methods: Sixty-six sialolith samples (51 from the submandibular glands and 15 from the parotid glands) were retrospectively collected. Their diameter and quality were measured.
Imaging Sci Dent
December 2024
Department of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, Seoul, Korea.
Purpose: The study was performed to examine the error associated with image superimposition when computed tomography (CT) images of the dental region are substituted with dental scan data, according to the block-out material used in dental impressions.
Materials And Methods: A typodont model was created by bonding orthodontic brackets to teeth on plaster dental stones using melted dental base-plate wax. In the experiment, 2 groups were compared: one using wax and the other using putty as the block-out material to prevent tearing of the impression material during the acquisition of dental impressions.
BMC Oral Health
December 2024
Faculty of Odonto-Stomatology, University of Health Sciences, Vietnam National University Ho Chi Minh City, Ho Chi Minh City, Vietnam.
Background: The success of a restoration largely depends on the quality of its fit. This study aimed to investigate the fit quality of monolithic zirconia veneers (MZVs) produced through traditional and digital workflows.
Methods: A typodont maxillary right central incisor was prepared.
A considerable portion of the global population is affected by pulpitis and periapical lesions. While the impact of infections caused by various microbes and host effector molecules in pulpal and periapical diseases is widely recognized, disease susceptibility and progression are also influenced by the dynamic interaction between host genetic factors and environmental influences. Apical periodontitis occurs as an inflammatory response to microorganisms present in the root canals of infected teeth.
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