Dentine reaction and repair depends on the number of cells present in the pulp, within these fibroblasts. The methods designed to obtain a reliable estimate of the amount of cellular elements of the dental pulp have been subjective and biased, especially when evaluating quantitative changes and potential reparative capacity in the presence of caries. The aim of this study was to estimate and quantitatively compare with stereological tools, number, density, volume and surface of fibroblasts in healthy teeth and reversible pulpitis diagnosis due to caries. We obtained premolar teeth from human tooth extractions, divided into healthy and carious groups, which were fixed and decalcified with 5 % nitric. Following the orientator protocol we obtained 5 sections of 5 μm from each tooth which were stained by H-E. The stereological counting of pulp fibroblasts (FP) with M42 multipurpose test was applied. Number densities (Nv), volume (Vv) and surface (Sv) were estimated, and calculated the means (±SD) for a tooth, and Mean (±SE) per group. Differences between groups were analyzed by t-test, p ≤0.05 a statistically significant value. In healthy teeth, the mean (±SE) for Nv FP was 0.393x105/mm3 (±0.020x105/mm3), Vv 15.467 % (±1.334 %) and Sv 16.330 mm2/mm3 (±1.274 mm2/ mm3). In decayed teeth, it was 0.447x105 Nv/mm3 (±0.019x105/ mm3), the Vv 20.171 % (±1.213 %) and Sv 20.150 mm2/mm3 (± 1.447 mm2/mm3). Comparing Nv, the FP carious group increased significantly (p =0.047), as Vv (p =0.0105) and Sv (p =0.013). There is an increased number of FP teeth with reversible pulpitis, which would determine their responsiveness. The methodology can be applied to determine the pulp behavior and odontoblast quantify response variables in impartially and reproducible atraumatic restorative treatments.

KEY WORDS: Stereology; Dental pulp; Fibroblasts.