Angiotensin II Regulates Proliferation and Function of Stem Cells of Apical Papilla.

INTRODUCTION: Stem cells of apical papilla (SCAP) may be affected by inflammatory mediators released by activation with lipopolysaccharide (LPS) from infected pulpal cavities of necrotic immature teeth. Therefore, this study aimed to investigate the presence of a local renin-angiotensin system (RAS) and the role of angiotensin II (Ang II) on the modulation of SCAP in vitro. METHODS: Primary cultures of SCAP were incubated with LPS (0.1-10 µg/mL) for cell viability and quantification of the chemokine CCL2. Components of RAS were searched by gene expression of angiotensinogen (AGTN), angiotensin converting enzyme (ACE), renin, angiotensin receptor 1 (AT1) and 2 (AT2), and Mas receptor. Ang II was investigated in SCAP supernatants. Immunofluorescence was used to detect AGTN and AT1. Next, cells were treated with Ang II for viability/proliferation assessment, quantification of CCL2 and interleukin 6, and mineralization assay. Data were evaluated by analysis of variance using Tukey post hoc comparisons or the Student t test. P values <.05 were considered to be significant. RESULTS: LPS increased CCL2 production at 1 and 10 µg/mL. The gene expression of AGTN, renin, ACE, and AT1 was detected, but only ACE was increased by LPS. Ang II peptide was found in SCAP supernatants but unaltered by LPS. Both AGTN and AT1 proteins were detected by immunostaining. Ang II significantly induced SCAP proliferation, increased CCL2 production, down-regulated IL-6 release, and reduced the SCAP mineralization rate. CONCLUSIONS: A local RAS was found at the apical papilla, and Ang II was able to modulate SCAP function in vitro.

Prostaglandin E2 Affects Interleukin 6 and Monocyte Chemoattractant Protein 1/CCL2 Production by Cultured Stem Cells of Apical Papilla.

INTRODUCTION: Root canal treatment of immature necrotic teeth is a major challenge in current endodontics. The effect of inflammatory mediators, such as prostaglandin, on the modulation of stem cells of the apical papilla (SCAP) is not completely understood. The aim of this study was to investigate the role of prostaglandin E2 (PGE2) on SCAP activation by Escherichia coli lipopolysaccharide (LPS) in vitro. METHODS: SCAP cultures were established and characterized. Increasing concentrations of lipopolysaccharide (0.1-10 µg/mL) were used to investigate cyclooxygenase-2 (COX-2/PTGS2) and PGE2 receptors (EP1-4) gene expression. Then, SCAP were treated with a COX-2 inhibitor (indomethacin) before treatment with different concentrations of LPS. The levels of the chemokine CCL2/monocyte chemoattractant protein 1 and interleukin (IL)-6 were detected in cell supernatants (24 hours) by enzyme-linked immunosorbent assay. Data analysis was performed using analysis of variance followed by the Tukey post test. RESULTS: The expression of COX-2 was up-regulated in the group treated with LPS at 1µg/mL compared with that in the control group. EP1-4 were detected in all experimental conditions at similar levels. SCAP treated with indomethacin presented a down-regulation in the production of LPS-induced CCL2 and the secretion of IL-6. CONCLUSIONS: SCAP showed increased COX-2 (PTGS2) gene expression induced by LPS and a PGE2-dependent production of IL-6 and CCL2.

Elementary Schoolteachers' Knowledge and Decision-making Regarding Dental Trauma.

PURPOSE: To evaluate elementary schoolteachers' knowledge and decision making regarding dental trauma in Porto Alegre, Brazil. MATERIALS AND METHODS: A questionnaire-based survey was conducted among elementary schoolteachers (n=442). Questions encompassed sociodemographic characteristics and decision making regarding dental trauma. Data on the appropriate answer regarding what to do with a traumatised or avulsed tooth were analysed with multiple logistic regressions, adjusting for age, gender, work experience and previous training. RESULTS: The study population consisted largely of women (90%), was 40 to 49 years old (44.3%) and had more than 15 years of work experience (56.6%). Women (OR=2.68/p=0.041), teachers under 30 years old (OR=4.95/p=0.041), those with more than 15 years of work experience (OR=8.95/p<0.001) or those who had already received previous dental trauma instructions (OR=1.95/ p=0.119) were more likely to choose the appropriate answer for an avulsion situation. Teachers under 30 years old (OR=2.88/ p=0.279), those with more than 15 years of work experience (OR=4.55/p=0.001) or those who had received previous training (OR=3.39/p=0.009) presented higher probabilites of choosing the appropriate answer for a crown fracture event. CONCLUSION: Greater work experience or previous instructions on how to approach dental trauma in the school environment were found to be major factors in schoolteachers' decision making regarding dental trauma.

Dental avulsion: are the dentist prepared to the correct management?

To evaluate the knowledge of dentists from the health units (HU) of Porto Alegre -Brazil, regarding the management of avulsion of permanent teeth.Material and Methods:All dentists (n = 117) from HU were invited to answer a self-applied questionnaire regarding the treatment and preservation of avulsed permanent teeth in different clinical scenarios, based on the guidelines of the International Association of Dental Trauma (IADT). The professional data were also collected. The correlation between the performance of each professional and professional data was performed, (StudentÆs t test, PearsonÆs and SpearmanÆs correlations), assuming 5% significance.Results:The response rate was 56.41%. The mean performance rate of the dentists regarding the clinical questions was 69.3%, but 37.4% had poor performance (less than 70% correct). The greatest number of hits was where the patient comes with the already replanted teeth (89.2%); 87.3% agreed in situations where the injured child reaches two hours of trauma with the tooth in a liquid medium, however in cases that period of trauma was more than two hours and tooth was dehydrated, the professionals performance was reduced (64.9%). There was a lack of knowledge about the use of intracanal medication (error rate of 56.9%); 41% are mistaken about the period to start endodontics procedures; 32.8% did the wrong about contention of avulsed teeth and clinical and radiographs follow-up. Dentists with postgraduate performed better than those without (p = 0.011)...