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

BACKGROUND: The literature is scanty regarding the effect of radiation therapy (RT) on the mechanical properties of immature permanent teeth. AIM: To evaluate the effect of RT on the fracture resistance of simulated immature teeth submitted to different types of root reinforcement. DESIGN: Sixty-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). RESULTS: In the intergroup comparison, nonirradiated teeth had higher fracture resistance (p < .05). Groups FP and FP + RT had higher fracture resistance (p < .001). CONCLUSION: Radiotherapy affected the fracture resistance of simulated immature teeth. Reinforcement with fibreglass posts increased the fracture resistance, regardless of the radiation.

Effect of the timing of radiation therapy on the push-out strength of resin cement to root dentine.

This study investigated the effect of radiation timing on the bond strength of resin cement to intraradicular dentine. Fifty human teeth were distributed into 5 groups (n = 10): Control (nonirradiated teeth), Before-RCT (teeth irradiated before root canal treatment), After-CH (teeth irradiated after canal preparation and placement of calcium hydroxide intracanal dressing), After-RCT (teeth irradiated after completion of root canal treatment) and After-FPL (teeth irradiated after luting of a glass fibre post). Each tooth received 70 Gy irradiation. The roots were sectioned for push-out strength testing. After-RCT and After-FPL groups had significantly lower push-out strength than the control at the middle third (p < 0.05). Control and After-CH groups had a higher percentage of cohesive dentine failure. Radiotherapy after root canal obturation and post luting adversely affected the adhesiveness of resin cement to intraradicular dentine. Teeth irradiated before root canal treatment and after placement of calcium hydroxide had the best performance.

Carcinoma Mucoepidermoide Juvenil: Relato de Caso e Revisão da Literatura / Juvenile mucoepidermoid carcinoma: a case report and literature review

O Carcinoma mucoepidermoide juvenil é uma doença rara, que ocorre mais frequentemente nas glândulas menores do palato duro. Os pacientes, em geral, referem edema progressivo e indolor. O tratamento de escolha é a ressecção cirúrgica, estando a radioterapia indicada no pós-operatório, em casos de presença de fatores de mau prognóstico. Relatamos o caso de uma paciente de 12 anos de idade com carcinoma mucoepidermoide juvenil em palato duro com radioterapia adjuvante.

Juvenile mucoepidermoid carcinoma is a rare disease that occurs most often in the minor glands of the hard palate. Patients usually report a progressive, painless swelling. The treatment of choice is surgical resection, with radiotherapy given postoperatively when poor prognostic factors are present. We report the case of a 12-year-old female with mucoepidermoid carcinoma of the hard palate with adjuvant radiotherapy.