Abstract The diagnosis of irreversible pulpitis (IP) depends on clinical data, especially the chief complaint of the patient, visual inspection, response to the application of stimuli, and radiographic examination. The characterization of nerve fibers (NF) in IP may contribute to better interpret painful symptoms, but has been barely explored. This study sought to characterize the density and integrity of NF in 16 samples of IP and in five healthy pulps (HP) using S-100 and PGP 9.5 markers. Immunohistochemistry was performed to determine the density/mm2 of S-100+ and PGP 9.5+ in NF. The amount of degenerated NF was obtained by subtracting the total NF density from the amount of intact NF. Associations between NF density and integrity and symptomatology were calculated. All samples were positive for S-100 and PGP 9.5. Compared to HP samples (38.20/mm2), IP samples had a lower density of intact NF (6.24/mm2). A significantly higher density of degenerated NF was found in IP samples with spontaneous pain (39.59/mm2) compared to those with provoked pain (23.96/mm2) (p = 0.02). No association was observed between intensity of the inflammatory infiltrate and NF density and integrity (p > 0.05). The findings of this study suggest that pulpitis may involve different stages of degeneration and may be more advanced in cases with spontaneous pain. The symptoms reported by affected individuals do not appear to depend on the intensity of the inflammatory infiltrate, but rather on the integrity of NF.

Objective: This study evaluated the effect of temperature and curing time on composite sorption and solubility. Material and Methods: Seventy five specimens (8×2 mm) were prepared using a commercial composite resin (ICE, SDI). Three temperatures (10°C, 25°C and 60°C) and five curing times (5 s, 10 s, 20 s, 40 s and 60 s) were evaluated. The specimens were weighed on an analytical balance three times: A: before storage (M1); B: 7 days after storage (M2); C: 7 days after storage plus 1 day of drying (M3). The storage solution consisted of 75% alcohol/25% water. Sorption and solubility were calculated using these three weights and specimen dimensions. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U Tests (α=5%). Results: The results showed that time, temperature and their interaction influenced the sorption and solubility of the composite (p<0.05). At 60°C, the composite sorption showed an inverse relationship with the curing time (p<0.05). The composite cured for 5 s showed higher sorption for the 40 s or 60 s curing times when compared with all temperatures (p<0.05). Curing times of 20 s and 40 s showed similar sorption data for all temperatures (p>0.05). The 60°C composite temperature led to lower values of sorption for all curing times when compared with the 10°C temperature (p<0.05). The same results were found when comparing 10°C and 25°C (p<0.05), except that the 20 s and 40 s curing times behaved similarly (p>0.05). Solubility was similar at 40 s and 60 s for all temperatures (p>0.05), but was higher at 10°C than at 60°C for all curing times (p<0.05). When the composite was cured at 25°C, similar solubility values were found when comparing the 5 s and 10 s or 20 s and 40 s curing times (p>0.05). Conclusions: In conclusion, higher temperatures or longer curing times led to lower sorption and solubility values for the composite tested; however, this trend was only significant in specific combinations of temperature and curing times.

OBJECTIVE: This study evaluated the presence of microorganisms and analyzed microscopically the pulp of 20 traumatized human teeth with intact crowns and clinical diagnosis of pulp necrosis, based on the association of at least three of the clinical criteria: crown discoloration, negative response to thermal and electric pulp vitality tests, positive response to vertical and horizontal percussion, pain on palpation or mobility. MATERIAL AND METHODS: Microbiological collection was performed from the root canals to evaluate the presence of microorganisms. The pulp samples were stained with hematoxylin and eosin (H.E.) for histological evaluation of possible morphological alterations. RESULTS: Analysis of results was performed by statistical tests (linear regression test and diagnostic analysis) and subjective analysis of the sections stained with H.E. and revealed that only 15% of the sample did not exhibit microbial development. The time elapsed between dental trauma and onset of endodontic intervention ranged from 15 days to 31 months; the percussion test presented high sensitivity (80%) for detection of microorganisms in the root canal of traumatized teeth; 3 teeth (15%) did not present pulp tissue, being characterized as complete autolysis; analysis of pulp samples was performed on the other 17 cases, among which 3 (15%) exhibited partial necrosis without possibility of repair and 14 presented complete necrosis; none of the clinical criteria employed for the diagnosis of pulp necrosis in traumatized teeth was pathognomonic. CONCLUSIONS: The present results allowed the following conclusions: with regard to microbiological findings, 85% of teeth presented microorganisms in the root canal, despite the presence of an intact crown. Concerning the microscopic findings, 100% of traumatized teeth presented pulp necrosis; the pulp vitality tests based on pulp response to heat, cold and vertical percussion were the most reliable to diagnose pulp necrosis in traumatized teeth.