Effect of radiation therapy on fracture resistance of simulated immature teeth submitted to root reinforcement

Abstract

BackgroundThe literature is scanty regarding the effect of radiation therapy (RT) on the mechanical properties of immature permanent teeth.AimTo evaluate the effect of RT on the fracture resistance of simulated immature teeth submitted to different types of root reinforcement.DesignSixty‐four human teeth simulating the Cvek stage 3 of root development were distributed into eight groups (n = 8), according to exposure or not to RT (70 Gy) and the root reinforcement method: Group NR (control)—no reinforcement/no RT; Group NR + RT (control)—no reinforcement/RT; Group PO—tricalcium silicate‐based cement (TS) apical plug/canal obturation/no RT; Group PO + RT—TS apical plug/canal obturation/RT; Group TS—canal filling with TS/no RT; Group TS + RT—canal filling with TS/RT; Group FP—TS apical plug/fibreglass post/no RT; and Group FP + RT—TS apical plug/fibreglass post/RT. Fracture resistance was determined using a universal testing machine (0.5 mm/min).ResultsIn the intergroup comparison, nonirradiated teeth had higher fracture resistance (p < .05). Groups FP and FP + RT had higher fracture resistance (p < .001).ConclusionRadiotherapy affected the fracture resistance of simulated immature teeth. Reinforcement with fibreglass posts increased the fracture resistance, regardless of the radiation.

Assessing push‐out bond strength in re‐irradiated teeth: Universal resin cement performance in self‐etch and self‐adhesive modes

“…70RT was submitted to a total radiation dose of The specimens were immersed in distilled and deionized water inside a plastic support aligned to be equidistant from the center of the beam to allow a proper radiation dose rate distribution (400 UM/min). 42,43 Radiation therapy was fractionated into daily doses of 2 Gy, 5 days a week, for 7 weeks (70RT group), or 14 weeks (70 + 70RT group) with 6MV of energy (photons). 8,[42][43][44] The distilled and deionized water was discarded at the end of each irradiation cycle.…”

“…42,43 Radiation therapy was fractionated into daily doses of 2 Gy, 5 days a week, for 7 weeks (70RT group), or 14 weeks (70 + 70RT group) with 6MV of energy (photons). 8,[42][43][44] The distilled and deionized water was discarded at the end of each irradiation cycle. The specimens were kept in artificial saliva at 37 C overnight to simulate the oral conditions, 45 and to perform a new cycle, the artificial saliva was replaced with new distilled and deionized water.…”

“…The specimens were kept in artificial saliva at 37 C overnight to simulate the oral conditions, 45 and to perform a new cycle, the artificial saliva was replaced with new distilled and deionized water. 42,43 At the end of the radiotherapy protocol (7 or 14 weeks), the specimens were stored in artificial saliva at 37 C until the experiment.…”

“…18 During radiotherapy, the specimens were completely immersed in distilled and deionized water, as recommended by other similar studies. 42,43 The distilled and deionized water was discarded at the end of each irradiation cycle, and the specimens were kept in artificial saliva overnight to simulate the oral conditions. 42,43 Artificial saliva is mainly composed of water, carboxymethyl cellulose, glycerin, and flavoring agents.…”

“…42,43 The distilled and deionized water was discarded at the end of each irradiation cycle, and the specimens were kept in artificial saliva overnight to simulate the oral conditions. 42,43 Artificial saliva is mainly composed of water, carboxymethyl cellulose, glycerin, and flavoring agents. 45 The viscosity and ion concentration of artificial saliva might affect the delivery of ionizing radiation to the specimens.…”