Effect of therapeutic dose X rays on mechanical and chemical properties of esthetic dental materials

Cruz, Adriana Dibo da; Sinhoreti, Mário Alexandre Coelho; Rastelli, Alessandra Nara de Souza; Bagnato, Vanderlei Salvador; Bóscolo, Frab Norberto

doi:10.1590/s1516-14392008000300014

Cited by 15 publications

(9 citation statements)

References 17 publications

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“…At the moment that ionizing radiation can cause a dissolution of the resin matrix, it can improve linking among polymerized chains after photoactivation through molecular excitation and continuous polymerization of the nonpolymerized surface layer [25,40]. Polymerized chains can form crosslinks through hydrogen bonds between OH or NH groups and ether or carbonyl groups, as well as among themselves, especially for hydroxyl-hydroxyl groups of monomers [41,42].…”

Section: Discussionmentioning

confidence: 99%

Effects of ionizing radiation on surface properties of current restorative dental materials

Amorim

Veríssimo

Ribeiro

et al. 2021

J Mater Sci: Mater Med

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To investigate the impact of radiotherapy on surface properties of restorative dental materials. A conventional resin composite—CRC (Aura Enamel), a bulk-fill resin composite—BFRC (Aura Bulk-fill), a conventional glass ionomer cement—CGIC (Riva self cure), and a resin-modified glass ionomer cement—RMGIC (Riva light cure) were tested. Forty disc-shaped samples from each material (8 mm diameter × 2 mm thickness) (n = 10) were produced according to manufacturer directions and then stored in water distilled for 24 h. Surface wettability (water contact angle), Vickers microhardness, and micromorphology through scanning electron microscopy (SEM) before and after exposition to ionizing radiation (60 Gy) were obtained. The data were statistically evaluated using the two-way ANOVA and Tukey posthoc test (p < 0.05). Baseline and post-radiation values of contact angles were statistically similar for CRC, BFRC, and RMGIC, whilst post-radiation values of contact angles were statistically lower than baseline ones for CGIC. Exposition to ionizing radiation statistically increased the microhardness of CRC, and statistically decreased the microhardness of CGIC. The surface micromorphology of all materials was changed post-radiation. Exposure to ionizing radiation negatively affected the conventional glass ionomer tested, while did not alter or improved surface properties testing of the resin composites and the resin-modified glass ionomer cement tested.

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Section: Discussionmentioning

confidence: 99%

Effects of ionizing radiation on surface properties of current restorative dental materials

Amorim

Veríssimo

Ribeiro

et al. 2021

J Mater Sci: Mater Med

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show abstract

“…Due to the use of photoinitiators in the monomers [ 14 ], the harmful effect of the ionising radiation (electromagnetic, but also particle radiation), and its minimal penetration depth when using radiopaque fillers in the monomer [ 8 , 15 ], ionising radiation has no relevance to clinical dentistry, in contrast to the field of science ( Figure 1 ) [ 16 , 17 , 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Is Micro X-ray Computer Tomography a Suitable Non-Destructive Method for the Characterisation of Dental Materials?

et al. 2021

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The aim of the study was to investigate the effect of X-rays used in micro X-ray computer tomography (µXCT) on the mechanical performance and microstructure of a variety of dental materials. Standardised bending beams (2 × 2 × 25 mm3) were forwarded to irradiation with an industrial tomograph. Using three-dimensional datasets, the porosity of the materials was quantified and flexural strength was investigated prior to and after irradiation. The thermal properties of irradiated and unirradiated materials were analysed and compared by means of differential scanning calorimetry (DSC). Single µXCT measurements led to a significant decrease in flexural strength of polycarbonate with acrylnitril-butadien-styrol (PC-ABS). No significant influence in flexural strength was identified for resin-based composites (RBCs), poly(methyl methacrylate) (PMMA), and zinc phosphate cement (HAR) after a single irradiation by measurement. However, DSC results suggest that changes in the microstructure of PMMA are possible with increasing radiation doses (multiple measurements, longer measurements, higher output power from the X-ray tube). In summary, it must be assumed that X-ray radiation during µXCT measurement at high doses can lead to changes in the structure and properties of certain polymers.

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“…A study performed to investigate the influence of therapeutic dose X-rays on the microhardness and degree of conversion of two different aesthetic restorative dental materials found that the therapeutic dose applied to cured material can promote linking and breaking of chain bonds. Thus, the authors recommended that the confection of a new dental restoration with a photo-cured composite resin should be made after the end of radiotherapy and never before, and old restorations should be attended and replaced when necessary 7 .…”

Section: Introductionmentioning

confidence: 99%

Comparative study between laser and conventional techniques for class V cavity preparation in gamma-irradiated teeth (in vitro study)

et al. 2017

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Objective:The purpose of this study was to compare laser with conventional techniques in class V cavity preparation in gamma-irradiated teeth.Methods:Forty extracted human teeth with no carious lesions were used for this study and were divided into two main groups: Group I (n = 20) was not subjected to gamma radiation (control) and Group II (n=20) was subjected to gamma radiation of 60 Gray. Standard class V preparation was performed in buccal and lingual sides of each tooth in both groups. Buccal surfaces were prepared by the Er,Cr:YSGG laser (Waterlase iPlus) 2780 nm, using the gold handpiece with MZ10 Tip in non-contact and the “H” mode, following parameters of cavity preparation – power 6 W, frequency 50 Hz, 90% water and 70% air, then shifting to surface treatment laser parameters – power 4.5 W, frequency 50 Hz, 80% water and 50% air. Lingual surfaces were prepared by the conventional high-speed turbine using round diamond bur. Teeth were then sectioned mesio-distally, resulting in 80 specimens: 40 of which were buccal laser-treated (20 control and 20 gamma-irradiated specimens) and 40 were lingual conventional high-speed bur specimens (20 control and 20 gamma-irradiated specimens).Results:Microleakage analysis revealed higher scores in both gamma groups compared with control groups. Chi-square test revealed no significant difference between both control groups and gamma groups (p=1, 0.819, respectively). A significant difference was revealed between all 4 groups (p=0.00018).Conclusion:Both laser and conventional high-speed turbine bur show good bond strength in control (non-gamma) group, while microleakage is evident in gamma group, indicating that gamma radiation had a dramatic negative effect on the bond strength in both laser and bur-treated teeth.

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Effect of therapeutic dose X rays on mechanical and chemical properties of esthetic dental materials

Cited by 15 publications

References 17 publications

Effects of ionizing radiation on surface properties of current restorative dental materials

Effects of ionizing radiation on surface properties of current restorative dental materials

Is Micro X-ray Computer Tomography a Suitable Non-Destructive Method for the Characterisation of Dental Materials?

Comparative study between laser and conventional techniques for class V cavity preparation in gamma-irradiated teeth (in vitro study)

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