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AIM: To evaluate in vitro the effect of calcium hydroxide [Ca(OH)(2)] and Er:YAG laser on bacterial endotoxin [also known as lipopolysaccharide (LPS)] as determined by nitric oxide (NO) detection in J774 murine macrophage cell line culture. METHODOLOGY: Samples of LPS solution (50 microg mL(-1)), Ca(OH)(2) suspension (25 mg mL(-1)) and LPS suspension with Ca(OH)(2) were prepared. The studied groups were: I - LPS (control); II - LPS + Ca(OH)(2); III - LPS + Er:YAG laser (15 Hz 140 mJ); IV - LPS + Er:YAG laser (15 Hz 200 mJ); V - LPS + Er:YAG laser (15 Hz 250 mJ), VI - Pyrogen-free water; VII - Ca(OH)(2). Murine macrophage J774 cells were plated and 10 microL of the samples were added to each well. The supernatants were collected for NO detection by the Griess reaction. Data were analysed statistically by one-way anova and Tukey's test at 5% significance level. RESULTS: The mean and SE (in micromol L(-1)) values of NO release were: I - 10.48 +/- 0.58, II - 6.41 +/- 0.90, III - 10.2 +/- 0.60, IV - 8.35 +/- 0.40, V - 10.40 +/- 0.53, VI - 3.75 +/- 0.70, VII - 6.44 +/- 0.60; and the values for the same experiment repeated after 1 week were: I - 21.20 +/- 1.50, II - 9.10 +/- 0.60, III - 19.50 +/- 1.00, IV - 18.50 +/- 0.60, V - 21.30 +/- 0.90, VI - 2.00+/- 0.20, VII - 6.80 +/- 1.70. There was no significant difference (P > 0.05) between the control and the laser-treated groups (III, IV and V), or comparing groups II, VI and VII to each other (P > 0.05). Group I had significantly higher NO release than group II (P < 0.05). Groups II and VI had similar NO release (P > 0.05). CONCLUSIONS: Calcium hydroxide inactivated the bacterial endotoxin (LPS) whereas none of the Er:YAG laser parameter settings had the same effectiveness.

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PURPOSE: The objective was to determine the level of contamination of toothbrushes by mutans streptococci using microbiological identification, to access the bacterial contamination using scanning electron microscopy (SEM) and to evaluate the efficacy of two toothbrush disinfectants. METHODS: Nineteen children used their toothbrushes once a day, for five consecutive days. The toothbrushes were then immersed into disinfectant solutions for 20 h: Group I--0.12% chlorhexidine gluconate; Group II--1% sodium hypochlorite; Group III--sterile tap water. They were then placed into test tubes containing CaSa B, for 3 to 4 days at 37 degrees C. The number of MS cfu was counted and the toothbrushes were submitted to SEM analysis. RESULTS: There was no bacterial growth in Groups I and II; Group III showed MS growth (range, 21 to 120 cfu). Scanning electron microscopy showed biofilm formation on toothbrush bristles. CONCLUSION: Immersion in 0.12% chlorhexidine gluconate and 1% sodium hypochlorite are efficient methods for toothbrush disinfection.

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Eighty root canals of the premolars of 4 dogs, with vital pulp, were instrumented and filled during the same session with the Sealapex, CRCS, Sealer 26, and Apexit sealers. The animals were sacrificed 180 days after root canal filling and their maxillae and mandibles were removed and fixed in 10% formalin. After routine histologic processing, the sections were stained with hematoxylin-eosin and Mallory trichrome. Histopathologic analysis showed that Sealapex was the sealer that best permitted the deposition of mineralized tissue at the apical level and was the only sealer that provided complete sealing (37.5% of cases). With the use of Sealapex, no inflammatory infiltrate occurred and there was no reabsorption of mineralized tissues. In contrast, partial sealing and a moderate inflammatory infiltrate occurred with the use of CRCS. When Apexit and Sealer 26 were used the absence of sealing was frequent and active reabsorption of mineralized tissues occurred in most cases. The inflammatory infiltrate predominating with the use of Apexit was of the severe type, whereas with the use of Sealer 26 the inflammatory infiltrate was mild or absent.

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The calcium hydroxide ionization of four root canal sealers (Sealapex, CRCS, Sealer 26, and Apexit) was studied by measuring conductivity and pH and by conducting atomic absorption spectrophotometry. Samples 6 mm in diameter and 15 mm long were prepared from these sealers. After setting and 48 h storage in a desiccator, five samples of each material were placed in 50 mL distilled water and analysed after 0,1,2,4,6 and 24 h and 5, 15 and 30 days. The results showed that Sealapex was the root canal sealer showing the highest pH, ionic calcium and total calcium values (P < 0.05) throughout the experimental period, followed by CRCS, Apexit and Sealer 26.

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Aiming to assess the presence of selected anaerobic microorganisms in root canals of human teeth with chronic apical periodontitis. 25 central and lateral upper incisors presenting with radiographic evidence of chronic apical periodontitis were studied. The pulp chamber was opened under aseptic conditions and samples of the root canal content were collected with sterile absorbent paper points, which were placed and dispersed in test tubes containing reduced transport medium RTT. Aliquots were dried on glass slides and stained by indirect immunofluorescence for detection of Actinomyces viscosus, Fusobacterium nucleatum, Porphyromonas gingivalis and Prevotella intermedia. The results showed a positive indirect immunofluorescence reaction in 24 of the 25 samples. Fourteen were positive for the specie Actinomyces viscosus, 12 for Prevotella intermedia, 10 for Fusobacterium nucleatum and 4 for Porphyromonas gingivalis. A semiquantitative assay was easily implemented for assessment of degree of infection by the organisms in individual cases.

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Periapical tissue response was evaluated histologically in teeth of 6-month-old dogs with incomplete root formation and periapical lesions in order to compare the effects of two calcium hydroxide-containing pastes prepared with different vehicles on induced root apex formation and repair of the periapical region. A group of teeth with no root canal dressing was used as control. After induction of the periapical lesion, the root canals were instrumented and filled with one of the two pastes (Calen and Calasept), which were renewed monthly for 90 days. At the end of the follow-up period (3 months), the animals were killed. Block sections from the actual areas were dissected free and prepared for histopathological analysis. Both calcium hydroxide pastes helped induce apical sealing and repair of the region, but the Calen paste yielded better results than Calasept. The induced mineralized tissue was predominantly of the cementoid type after the use of both pastes, but the inflammatory infiltrate was significantly less intense with the use of the Calen paste. In the control group, the absence of a root canal dressing impaired the process of periapical repair and yielded no apical root closure in any of the cases analyzed.

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