New restorative systems allow for more esthetic restorations, but may cause adverse pulp tissue reactions due to either physical or chemical effects. This study evaluated the effect of glass ionomer liners in limiting temperature rise during composite placement with visible light-cure lamps. Neither chemical or light-cured glass ionomer liners limited the amount of pulp chamber temperature rise. Exposure time of the light-cure lamps played the greatest role in pulpal temperature rise regardless of glass ionomer liner of composite. Visible light-cure lamps varied in the amount of heat emitted.