RESUMO
ABSTRACT Objective: To evaluate the pulpal temperature changes due to the polymerisation of resin and glass ionomer-based materials in dentine thicknesses in immature permanent teeth with open apices. Material and Methods: Forty extracted sound human third molar teeth with open apices were included. The width of the cavities prepared on the occlusal surface was 4×5 mm. The depth was 2 mm in the resin groups. 4 mm in the groups in which glass ionomer liner was applied before composite restoration. The coronal parts of the samples were then placed on an acrylic plate with three gaps for feeding-extraction needles and the thermocouple. The temperature changes were recorded. The data was analyzed by SPSS. Statistical significance was accepted as p<0.05. Results: The temperature increase in the group of 1 mm remaining dentin thickness revealed higher results than the values detected from the 2 mm group (1.01 °C) (p=0.00). The mean values (1.49 °C, 1mm) of temperature changes in only glass ionomer applied group were lower than the avarage values (2.210°C, 1mm) determined in the polymerization process of resin composites with light-emitting diode devices. Conclusion: In a remaining dentin thickness of 1 mm in teeth with open apices, using a glass ionomer liner might be a useful effort for protecting the pulp from the heat generated by polymerisation devices.