ABSTRACT
Purpose: To evaluate the morphological alterations in enamel and dentin of primary teeth following radiotherapy (RT) and to determine the best adhesive technique and time to carry out restorative procedures.
Methods: Enamel and dentin fragments of primary teeth were randomly assigned into four groups (n=30): G1 (control)-non-irradiated, only restorative procedure; G2- restorative procedure immediately before RT; G3-restorative procedure 24 hours after RT; and G4-restorative procedure six months after RT. Each group was divided into one of two subgroups according to the adhesive system used for restoration: (1) AdperSingle Bond 2 (SB); and (2) ClearfillSE Bond (CL). The specimens were submitted to fractionated RT until they reached the final dose of 60 Gy. They were then subjected to confocal microscopy and the shear bond strength test. Data were analyzed using two-way analysis of variance followed by Tukey's tests ( α = five percent).
Results: Morphological changes were first observed in enamel and dentin after 40 Gy of irradiation. G4 bond strength values were similar to G1 in the CL and SB groups for enamel and in the CL group for dentin (P >0.05). G2 showed the lowest values for enamel and dentin (P <0.05). In G3, CL presented the highest strength values in enamel; for G4, the highest values were found in dentin (P <0.05).
Conclusions: Radiotherapy affected the morphological surface of enamel and dentin. The restorations placed immediately after RT had the weakest shear bond strength, and the restorations placed six months after RT had similar means of bond strength compared to the nonirradiated teeth in enamel, regardless of the adhesive system used. In dentin, CL showed better performance than SB.
Subject(s)
Dental Bonding , Dentin-Bonding Agents , Composite Resins , Dental Cements , Dentin , Humans , Materials Testing , Resin Cements , Shear Strength , Tooth, DeciduousABSTRACT
Os autores analisam citigeneticamente doze caos de leucemia näo-linfóide aguda da infância (LNLA), objetivando estabelecer correlaçöes entre alteraçöes cromossômicas, evoluçäo e progressäo da doença. 91,66 por cento dos casos exibiam anomalias. Dois pacientes com classificaçäo FAB M1 e M2 apresentaram translocaçäo t(8;21), associada à monossomia do X e à trissomia desse cromossomo, mais alteraçäo do 7, respectivamente. Ambos faleceram, o primeiro após transplante de medula óssea com recidiva da doença e o segundo com septicemia, confirmando o caráter agerssivo dessa translocaçäo quando associada a outras alteraçöes cromossômicas. Em um dos casos a presença de alteraçöes cromossômicas complexas foi fundamental p[ara a confirmaçäo diagnóstica de eritroleucemia. Cinco pacientes exibiram alteraçöes cromossômicas primárias e seis do tipo secundário. No grupo com alteraçöes primárias se encontram os três pacientes vivos livres da doença. No grupo com alteraçöes secundárias, todos foram a óbito, dois por recidiva, dois por resistência à doença e dois por septicemia, após entrar em remissäo...