Andreza Maria Fábio Aranha

Effects of light-curing time on the cytotoxicity of a restorative composite resin on odontoblast-like cells.

This in vitro study evaluated the cytotoxicity of an experimental restorative composite resin subjected to different light-curing regimens. Methods Forty round-shaped specimens were prepared and randomly assigned to four experimental groups (n=10), as follows: in Group 1, no light-curing; in Groups 2, 3 and 4, the composite resin specimens were light-cured for 20, 40 or 60 s, respectively. In Group 5, filter paper discs soaked in 5 μL PBS were used as negative controls. The resin specimens and paper discs were placed in wells of 24-well plates in which the odontoblast-like cells MDPC-23 (30,000 cells/cm2) were plated and incubated in a humidified incubator with 5% CO2 and 95% air at 37ºC for 72 h. The cytotoxicity was evaluated by the cell metabolism (MTT assay) and cell morphology (SEM). The data were analyzed statistically by Kruskal-Wallis and Mann- Whitney tests (p<0.05). Results In G1, cell metabolism decreased by 86.2%, indicating a severe cytotoxicity of the non-light-cured composite resin. On the other hand, cell metabolism decreased by only 13.3% and 13.5% in G2 and G3, respectively. No cytotoxic effects were observed in G4 and G5. In G1, only a few round-shaped cells with short processes on their cytoplasmic membrane were observed. In the other experimental groups as well as in control group, a number of spindle-shaped cells with long cytoplasmic processes were found. Conclusion Regardless of the photoactivation time used in the present investigation, the experimental composite resin presented mild to no toxic effects to the odontoblast-like MDPC-23 cells. However, intense cytotoxic effects occurred when no light-curing was performed.

Evidence Supporting a Protective Role for Th9 and Th22 Cytokines in Human and Experimental Periapical Lesions

INTRODUCTION The development of periapical granulomas is dependent on the host response and involves Th1, Th2, Th17, and Treg-related cytokines. The discovery of new Th9 and Th22 subsets, with important immunomodulatory roles mediated by interleukin (IL)-9 and IL-22, respectively, emphasizes the need for reevaluation of current cytokine paradigms in context of periapical lesions. We investigated the expression of IL-9 and IL-22 in active and stable human granulomas and throughout experimental lesion development in mice. METHODS Periapical granulomas (N = 83) and control specimens (N = 24) were evaluated regarding the expression of IL-9 and IL-22 via real-time polymerase chain reaction. Experimental periapical lesions were induced in mice (pulp exposure and bacterial inoculation) and the lesions evolution correlation with IL-9 and IL-22 expression kinetics was evaluated. RESULTS IL-9 and IL-22 mRNA expression was higher in periapical lesions than in control samples; higher levels of IL-9 and IL-22 were observed in inactive than in active lesions. In the experimental lesions model, increasing levels of IL-9 and IL-22 mRNA were detected in the lesions, and inverse correlations were found between IL-9 and IL-22 and the increase of lesion area in the different time point intervals. CONCLUSIONS Our results suggest that Th9 and Th22 pathways may contribute to human and experimental periapical lesion stability.

Chronology of Deciduous Teeth Eruption in Children With Cleft Lip and Palate

Objective To determine the chronology and sequence of eruption of the deciduous teeth in children with complete unilateral cleft lip and palate. Design Cross-sectional study. Setting Hospital for Rehabilitation of Craniofacial Anomalies, University of Sao Paulo, Bauru, Sao Paulo, Brazil. Sample A total of 435 children aged 0 to 48 months who presented with complete unilateral cleft lip and palate. Results All teeth on the cleft side in both jaws for both sexes presented a higher mean age of eruption than their homologues at the noncleft side. This difference was statistically significant for the maxillary lateral incisor, maxillary cuspid, and mandibular lateral incisor. There was a statistically significant sex difference regarding the mean age of eruption only for the maxillary second molar for the girls and mandibular cuspid for the boys. The maxillary lateral incisor on the cleft side was the last tooth to erupt, thus modifying the sequence of eruption of the deciduous teeth. Conclusions The results suggest the interference of the cleft on the chronology of eruption of the deciduous teeth that are directly related to it.

The Role of Chemokines and Cytokines in the Pathogenesis of Periodontal and Periapical Lesions: Current Concepts

The oral cavity is a complex environment that may harbor more than 750 bacterial species. Proper oral hygiene is essential to maintain the equilibrium of microbial community and oral health. The ecological balance can be compromised in inadequate microbial control situations and an oral infection can be evoked. The bacteria can aid in the formation of dental plaque and caries, leading to periodontal disease (PD) and periapical lesion (PL). PD is the most common chronic inflammatory disorder of microbial origin that affects toothsupporting tissues including the periodontal ligament and the alveolar bone. Dental caries is characterized by demineralization of enamel and dentine produced by microorganisms’ acids. This process can cause pulp necrosis and root canal infection and the progression through the root apex can induce PL. PD and PLs constitute inflammatory and immune response against oral pathogens. Both processes encompass pathogenic mechanisms of inflammation-mediated soft tissue destruction and bone resorption. The etiopathogenesis of these diseases have been extensively investigated over the last decades and the role of several cell types, cytokines and pathways has been described (Graves, 2008, Graves et al., 2011a, Nair, 1997). Last decades research have documented the importance and commitment of immune system to protect the host from pathogen and also the paradoxical effect accounting for the bone resorption observed in these diseases. More recently, the pattern of immune cell response involved in the lesions progression (i.e. Th1, Th2, Th17, Th9 or T regulatory) has received particular attention (Cardoso et al., 2009, Colic et al., 2009a, Gaffen & Hajishengallis, 2008, Ohlrich et al., 2009, Queiroz-Junior et al, 2011). Although chemokines and cytokines are pivotal to determine these Th patterns, not much is known regarding the expression of these markers in the regulation of bone resorption in sites of PD and PL. This

Tooth ankylosis in deciduous teeth of children with cleft lip and/or palate

The present study aimed at evaluating the prevalence of tooth ankylosis in deciduous molars of Caucasian children with cleft lip and/or palate aged 5 to 12 years, of both genders. A total of 330 patients seen at the Hospital for Rehabilitation of Craniofacial Anomalies of the University of São Paulo for routine treatment were clinically evaluated. The prevalence of ankylosis was analyzed in relation to gender, age range (5-7, 8-10, 11-12 years), type of cleft, affected tooth and arch. The total group showed a prevalence of 18%, with no statistical difference between genders and among types of cleft; ankylosis was more often in the mandibular arch, lower first molars and among children in the age ranges 8-10 and 11-12 years. The results agreed with those observed in the related literature for patients without clefts, pointing out the absence of influence of the cleft on the prevalence of ankylosis. This reinforces the importance of early diagnosis of this anomaly and of the treatment of choice, which are similar in patients with or without clefts.

In vitro effectiveness of Brazilian brown propolis against Enterococcus faecalis

The aim of this study was to evaluate the in vitro antimicrobial activity of Brazilian brown propolis as an intracanal medication against Enterococcus faecalis. Thirty dentin discs prepared from intact freshly extracted bovine maxillary central incisors were infected with E. faecalis for 21 days. The specimens were distributed into six groups according to the medicament used as follows: G1- calcium hydroxide paste; G2- Carbowax 400 (control group); G3- 20% brown propolis paste; G4- 40% brown propolis paste; G5- 20% brown propolis paste + calcium hydroxide paste; and G6- 40% brown propolis paste + calcium hydroxide paste. The experimental pastes were placed into the canal lumen and left for 14 days. After each period, irrigation was performed with sterile saline to remove the medicament, and the canals were dried with sterile paper points. The dentin chips were removed from the canals with sequential sterile round burs at low speed and were immediately collected in separate test tubes containing BHI broth. The tubes were incubated at 37°C, and microbial growth was analyzed by spectrophotometry after 15 days. All the experimental medications significantly reduced the number of viable bacteria. The G4 and G5 pastes were more effective than the G1 paste, with 35.8%, 41%, and 21.3% antibacterial activity, respectively. Brazilian brown propolis shows antibacterial capacity against E. faecalis.