Dental cutting behaviour of mica‐based and apatite‐based machinable glass‐ceramics

Abstract

Some recently developed industrial ceramics have excellent machinability properties. The objective of this study was to evaluate the dental cutting behaviour of two machinable glass-ceramics, mica-containing Macor-M and apatite- and diopside-containing Bioram-M, and to compare them with the cutting behaviour of a composite resin typodont tooth enamel and bovine enamel. Weight-load cutting tests were conducted, using a diamond point driven by an air-turbine handpiece, While the transverse load applied on the point was varied, the handpiece speed during cutting and the volume of removal upon cutting were measured. In general, an increase in the applied load caused a decrease in cutting speed and an increase in cutting volume. However, the intensity of this trend was found to differ between four workpieces. Cutting Macor-M resulted in the second-most reduced cutting speed and the maximum cutting volume. Cutting Bioram-M gave the least reduced cutting speed and the minimum cutting volume. It was suggested that two machinable glass-ceramics could be employed as typodont teeth. This study may also contribute to the development of new restorative dental ceramic materials, prepared by machining.

Evaluation of machinability and flexural strength of a novel dental machinable glass-ceramic

“…11,23,25 Therefore, cleavage of mica crystals localizes the fracture of the glass matrix in the microscopic scales and facilitates the formation of powered chips. 19,20 In this study, the outcome that the machinability of Vita MK II was lower than that of the new machinable glassceramic containing calcium-mica (Group 2) may be the result of Vita MK II without cleavage plane.…”

“…19,20 In a more recent study, Watanabe et al 21 and Kikuchi et al 22 evaluated machinability of dental materials through volume loss of materials which was calculated from the density and the weight loss. This method applies to uniformly dense materials.…”

Castable polymer-infiltrated ceramic network composite for training model tooth with compatible machinability to human enamel

“…However, these previous studies did not perform quantitative evaluations for machinability. Meanwhile, Taira et al conducted quantitative assessments of machinability of bovine enamel and tooth-model materials [10][11][12] . The study examined the machinability of the mica-containing glass-ceramic, apatite-and diopside-containing glass-ceramic, and resin composite 11) , and showed that hardness as well as machinability of these materials differed from that of bovine enamel.…”

“…Owing to the difference in the characteristics between natural teeth and resinbased materials, it is difficult for dental students to experience the grinding sensation of natural teeth during the tooth preparation training which is based on the use of phantom model teeth. To overcome this issue, some materials have been investigated for the model teeth [8][9][10][11][12] . Previous studies examined the mechanical properties of restorative materials, such as porcelain, filler-dispersed resin composites, and polymer-infiltrated ceramic network (PICN) composites 8,9) as potential materials for teeth used in the training model.…”

Relationships between tissue properties and operational parameters of a dental handpiece during simulated cavity preparation

“…Rotational frequency of dental handpieces has been measured using methods such as mechanical tachometers, 12,13 stroboscopes, 14–16 optical counting devices, 17–20 magnetic systems, 21–24 and sound frequency detectors. 25 Of these methods, sound frequency has been one of the easiest techniques to implement.…”