TLD characteristic of glass, feldspathic and lithium disilicate ceramics

Investigation of zinc polycarboxylate cement used in dental treatments in terms of retrospective dosimeter

Zinc polycarboxylate cement is one of the few dental materials that demonstrate true adhesion to tooth structure. It is suitable for use in living organisms without causing harm. Its strong adhesion to teeth and low level of irritancy are two important parameters for the dental applications. In this study, the dosimetry properties of zinc polycarboxylate cement using thermoluminescence (TL) method were investigated and determined the effectiveness of its use as a good dosimeter. According to the results of this study, the sample shows a good TL properties with three main peaks found around 140°C, 220°C and 330°C. It has a wide linear dose response between 72 Gy and 2.3 kGy and good reusability of the TL peak found at 330°C. Unfortunately, the TL peak intensity values are rapidly faded within a short waiting time interval. Zinc polycarboxylate cement, which is frequently used in dental crowns, can be used as a retrospective dosimeter for measuring the amount of radiation in space studies and nuclear accidents due to its wide linear dose-response curve in the high dose region.

Thermoluminescence in pumice stone collected from the Mediterranean coast

Pumice is a low-density, light-coloured volcanic rock (igneous rock) formed when the magma from a volcanic eruption is suddenly cooled. It has a porous structure and can be different colours and have different densities. Pumice stone, unlike other rock, does not sink in water because it has a low density. In the present study, the thermoluminescent (TL) dosimetric characteristics, such as the dose-response, TL signal fading as a function of storage time, heating rate, and reusability of pumice collected on the Mediterranean coast were investigated. From this study, it was concluded that the pumice stone showed TL properties with a TL glow curve including an obviously wide peak at ∼200°C. A wide linear dose-response region up to 144 Gy, low fading of the TL signal when it was kept in a dark room for a long time, and poor reusability properties were observed for dosimetry use.

Thermoluminescence Characteristic of Calcite with Gaussian Process Regression Model of Machine Learning

Thermoluminescence (TL) is defined as a luminescent phenomenon that can be detected when an insulator or semiconductor is thermally stimulated. Defective crystals store radiation until they are stimulated. Thermoluminescence is a method of monitoring the absorbed dose of dosimeters. The irradiation crystal is heated to 500 °C to display the absorbed dose as a luminescent light. The thermoluminescence dosimetric properties of calcite obtained from nature were investigated in this study. Machine learning (ML) was also examined utilizing Gaussian process regression (GPR) for stimulated TL characteristics. According to the experimental output, the TL glow curve has two main peaks located at 90 ^o C and 240 ^o C with good dosimetric properties. In the four regression models of GPR, the data of heating rate of 3 ^o C/sec has the lowest residual.

Feldspathic and Lithium Disilicate Onlays with a 2-Year Follow-Up: Split-Mouth Randomized Clinical Trial

The present study was a prospective, controlled, randomized, clinical short-term trial aiming to evaluate the clinical performance of adhesively luted, lithium disilicate and feldspathic glass-ceramics onlays over a period up to 2 years. A total of 11 patients (7 female, 4 male; age range: 18-60 years, mean age: 39 years) were selected for this study. Each patient received a maximum of two restorations per group in a split-mouth-design. LD: Eleven onlays, performed with lithium disilicate-based ceramic (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein), and FP: Eleven onlays, performed with feldspathic ceramic (Vita Mark II, Vita Zanhfabrik, Bad Säckingen). Recalls were performed at 2 weeks (baseline = R1), 1 year (R2) and 2 years (R3) after the cementation by three calibrated blinded independent investigators using mirrors, magnifying eyeglasses, probes and bitewing radiographs. The postoperative sensitivity, secondary caries, marginal integrity, marginal discoloration, color match, surface roughness, tooth integrity, and restoration integrity were evaluated. The Friedman test was used to determine if there was a statistically significant difference in time-to-time comparison of the parameters in the ceramics restorations. A total of 95.4% of the restorations were clinically acceptable at the 2-year recall, without a difference for any evaluation parameter for both ceramic materials. Based on the 2-year data, the CAD-CAM onlays manufactured with feldspathic and lithium-disilicate based ceramics showed similar clinical performance.