Evaluation of warming on external root surface during filling of simulated internal root resorption cavities with three different warm Gutta Percha techniques

The aim of this study was to evaluate the temperature on external root surface during filling of internal root resorption cavities with warm gutta percha techniques. Sixty mandibular premolar teeth were used for this study. Root canals were prepared with ProTaper up to size F4. Teeth were vertically sectioned into two halves and internal resorption cavities were created with aplication of nitric acid at the middle section of root canal. Then root sections were re-cemented together in the same position. Dentin thickness between outer border of internal resorption cavities and root surface was standardised and two different thicknesses created ( 0.5mm, 1mm). Subjects divided into six groups according dentin thickness and root filling techniques used. Thermoplastic injectable gutta-percha (TPE) (Beefill), continuous wave of condensation (DDK) (Beefill 2in1) and carrier-based gutta-percha (KTS) (Herofill) techniques were used for root canal filling. Temperature rises on external root surface was measured with infra-red thermal camera. Kolmogorov-Smirnov, One-Way ANOVA, post hoc Bonferroni and Student-T tests were used for statistical analysis. Heat values at small resorption cavities were statistically significantly higher at DDK and TPE techniques than KTS (P˂0.05). Temperature values at large resorption cavities with DDK technique were higher than TPE and DDK (P˂0.05). When resorption sizes compared, temperature values at large resorptions were higher than small ones with all techniques (P˂0.05). Dentin thickness between root canal and root surface reduces with the increasing size of internal root resorption cavities. Reduction of dentinal thickness smaller than 0.5mm can result in temperature rise up to pathological level at outer root surface when warm gutta-percha fillig techniques are used. Keywords: Root resorption, Thermography, Nitric acid, Root canal, Root canal obturation