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Effects of Thermal Cycling on Surface Hardness, Diametral Tensile Strength and Porosity of an Organically Modified Ceramic (ORMOCER)-Based Visible Light Cure Dental Restorative Resin
Published in P. Mereena Luke, K. R. Dhanya, Didier Rouxel, Nandakumar Kalarikkal, Sabu Thomas, Advanced Studies in Experimental and Clinical Medicine, 2021
Dental restorative material is expected to remain lifelong in the oral environment, which is a thermal cycling system with temperature variation from 5 to 55°C, which changes with the food habits. Variation in temperature can make irreversible changes in properties of the restorative material which adversely affects the clinical performance.
An Introduction to Bioactivity via Restorative Dental Materials
Published in Mary Anne S. Melo, Designing Bioactive Polymeric Materials for Restorative Dentistry, 2020
Mary Anne S. Melo, Ashley Reid, Abdulrahman A. Balhaddad
This book will examine the development of biointeractive/bioactive materials in a context more closely related to restorative dentistry, with the explicit acknowledgment that much of the information has been developed in other specialty disciplines in dentistry. As such, this book will attempt to provide a better understanding of the relative position of bioactive materials in the context of the past and the present status of dental restorative materials.
Release of Nickel Ion from the Metal and Its Alloys as Cause of Nickel Allergy
Published in Jurij J. Hostýnek, Howard I. Maibach, Nickel and the Skin, 2019
Jurij J. Hostýnek, Katherine E. Reagan, Howard I. Maibach
Bumgardner and Lucas (1994) further evaluated the dental alloys Neptune, Rexalloy, Regalloy T, and Vera Bond for their suitability as dental restorative materials, by an electrochemical corrosion test and the cytotoxicity of the resulting metal ion release in culture media. Pure nickel metal released on the order of 400 ppm nickel in cell culture media, compared with 100 to 255 ppb from the four Ni-Cr dental casting alloys. Particularly the comparison of the effect of beryllium as a component of the dental alloys Regalloy T and Vera Bond on their corrosion resistance with nonberyllium, nickel base alloys revealed increased corrosivity due to the presence of Be. All alloys demonstrated decreased corrosion rates in cold solution sterilized samples in complete cell culture media. The viability of human gingival fibroblast cell cultures was not affected by metal ions released from any of the nickel alloys tested.
A review on potential toxicity of dental material and screening their biocompatibility
Published in Toxicology Mechanisms and Methods, 2019
Shahriar Shahi, Mutlu Özcan, Solmaz Maleki Dizaj, Simin Sharifi, Nadin Al-Haj Husain, Aziz Eftekhari, Elham Ahmadian
Biological and immunological adverse reactions attributed to dental materials are infrequent, and the reported side effects are not severe. However, this completely depends on the kind of the materials used and the technique used by staff. In some rare cases, severe reactions have been published. Mjör (1992) reviewed the problems and benefits of dental restorative materials and their adverse effects. He emphasized that the allergic reactions are the most confirmed side effects to dental materials due to their known allergen components such as transition metals and solutions such as formaldehyde (Mjör 1992). Formaldehyde may form as by-product of unreacted monomers from some dental resins that may lead to even enhanced tissue responses.
Cost-effectiveness of partial versus stepwise caries removal of deep caries lesions - a decision-analytic approach
Published in Acta Odontologica Scandinavica, 2023
Nikki Savolainen, Thomas Kvist, Johanna Mannila
Further research on the PCR and SW treatment outcomes is still needed, especially randomised controlled trials with longer follow-up periods since retreatments are resource demanding. It would also be of interest to investigate whether the type of dental restorative material used during the intervention has an effect on the clinical success rate.
Effect of thermal cycling on temperature changes and bond strength in different test specimens
Published in Biomaterial Investigations in Dentistry, 2020
Sigfus Thor Eliasson, Jon Einar Dahl
The most used methods for aging resin-based materials are storing in water and thermal cycling. Less clinically oriented and extreme aging procedures require boiling in water for 8 h and immersion in citric acid for a week [3,4]. Thermocycling is intended to simulate the thermal stress to which the restorative materials and the teeth would be exposed to by consuming drinks and food to get years of aging for the specimens in a short period of time [5]. Unfortunately, a standardized protocol for artificial aging of dental restorative materials does not exist, despite volumes of in vitro studies published and the fact that thermocycling is considered an inevitable method for ageing restorative materials [6]. Variations in the thermal cycling regimens are large in the literature and comparison of results is, therefore, often difficult [7]. Several investigators have measured the temperature fluctuations in the mouth when eating hot and cold food [8–12]. When reviewing the literature, it appears to be a general agreement among investigators that thermal cycling specimens between 5 °C and 55 °C is appropriate well to cover oral temperature fluctuations in the mouth [13]. Soh and Selwyn measured the temperature changes in the pulp chamber of molar teeth when thermocycled between 5 °C and 55 °C water baths with a 30 s dwell time [14]. They found 30 s to be insufficient time to reach water bath temperatures in the pulp chamber and longer dwell times to be needed. Fabris et al. used the finite elements method to simulate the effect of thermal stressing to porcelain fused with metal or zirconia. Their results indicated that the geometry of specimens significantly influenced the stresses generated and maximum stress to be located at the interface between the materials [15]. No studies could be found on the thermal stress developed nor on the thermal gradient within the various sized and shaped composite or tooth/composite specimen combinations during thermal cycling. It appears, however, from the literature that no agreement has been reached on dwell times and the number of cycles when specimens are thermocycled and that investigators determine these parameters on the bases of their convenience [13].