Root canal dressings for revascularization influence in vitro mineralization of apical papilla cells.

Endodontic revascularization is based on cell recruitment into the necrotic root canal of immature teeth after chemical disinfection. The clinical outcome depends on the ability of surviving cells from the apical tissue to differentiate and promote hard tissue deposition inside the dentinal walls. OBJECTIVE: To investigate the effect of calcium hydroxide (CH) and modified triple antibiotic paste (mTAP - ciprofloxacin, metronidazole and cefaclor) on the viability and mineralization potential of apical papilla cells (APC) in vitro . MATERIAL AND METHODS: APC cultures were kept in contact with CH or mTAP (250-1000 µg/mL) for 5 days, after which cell viability was assessed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Next, APCs were subjected to CH or mTAP at 250 µg/mL for 5 days before inducing the differentiation assay. After 14 and 21 days, calcium deposition was assessed by the Alizarin Red S staining method, followed by elution and quantification using spectrophotometry. Data were analyzed using ANOVA followed by Tukey post hoc test. RESULTS: CH induced cell proliferation, whereas mTAP showed significant cytotoxicity at all concentrations tested. APC treated with CH demonstrated improved mineralization capacity at 14 days, while, for mTAP, significant reduction on the mineralization rate was observed for both experimental periods (14 and 21 days). CONCLUSION: Our findings showed that CH induces cell proliferation and improves early mineralization, whereas mTAP was found cytotoxic and reduced the mineralization potential in vitro of APCs.

Root canal dressings for revascularization influence in vitro mineralization of apical papilla cells

Abstract Endodontic revascularization is based on cell recruitment into the necrotic root canal of immature teeth after chemical disinfection. The clinical outcome depends on the ability of surviving cells from the apical tissue to differentiate and promote hard tissue deposition inside the dentinal walls. Objective To investigate the effect of calcium hydroxide (CH) and modified triple antibiotic paste (mTAP - ciprofloxacin, metronidazole and cefaclor) on the viability and mineralization potential of apical papilla cells (APC) in vitro . Material and Methods APC cultures were kept in contact with CH or mTAP (250-1000 µg/mL) for 5 days, after which cell viability was assessed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Next, APCs were subjected to CH or mTAP at 250 µg/mL for 5 days before inducing the differentiation assay. After 14 and 21 days, calcium deposition was assessed by the Alizarin Red S staining method, followed by elution and quantification using spectrophotometry. Data were analyzed using ANOVA followed by Tukey post hoc test. Results CH induced cell proliferation, whereas mTAP showed significant cytotoxicity at all concentrations tested. APC treated with CH demonstrated improved mineralization capacity at 14 days, while, for mTAP, significant reduction on the mineralization rate was observed for both experimental periods (14 and 21 days). Conclusion Our findings showed that CH induces cell proliferation and improves early mineralization, whereas mTAP was found cytotoxic and reduced the mineralization potential in vitro of APCs.

Microbiological analysis of infected root canals from symptomatic and asymptomatic teeth with periapical periodontitis and the antimicrobial susceptibility of some isolated anaerobic bacteria.

The purpose of the present study was to investigate the correlation between the composition of the bacterial flora isolated from infected root canals of teeth with apical periodontitis with the presence of clinical signs and symptoms, and to test the antibiotic susceptibility of five anaerobic bacteria mostly commonly found in the root canals of symptomatic teeth against various substances using the E-test. Microbial samples were taken from 48 root canals, 29 symptomatic and 19 asymptomatic, using adequate techniques. A total of 218 cultivable isolates were recovered from 48 different microbial species and 19 different genera. Root canals from symptomatic teeth harbored more obligate anaerobes and a bigger number of bacterial species than the asymptomatic teeth. More than 70% of the bacterial isolates were strict anaerobes. Statistical analysis used a Pearson Chi-squared test or a one-sided Fisher's Exact test as appropriate. Suggested relationships were found between specific microorganisms, especially gram-negative anaerobes, and the presence of spontaneous or previous pain, tenderness to percussion, pain on palpation and swelling amoxicillin, amoxicillin + clavulanate and cephaclor were effective against all the strains tested. The lowest susceptibility rate was presented by Prevotella intermedia/nigrescens against Penicillin G. Our results suggested that specific bacteria are associated with endodontic symptoms of infected teeth with periapical periodontitis and the majority of the anaerobic bacterial species tested were susceptible to all antibiotics studied.

Prevalência de Haemophilus influenzae resistentes a ampicilina, cefaclor, cefotaxime, cloranfenicol e cotrimoxazol isolados de laboratórios na cidade de Säo Paulo / Prevalence of Haemophilus influenzae resistant to ampicillin, cefaclor, cefotaxime, chloramphenicol and cotrimoxazol isolated from laboratories in the city of Säo Paulo, Brazil

Objetivo: Determinar a resistência à ampicilina e outros antimicrobianos de amostras de H. influenzae isoladas de diferentes materiais clínicos. Métodos; As amostras de H. influenzae foram identificadas por cultura com fatores V e X e prova do ácido amino-levulínico. A produçäo de ß-lactamase (ßLac) foi detectada pela nitrocefina. A sensibilidade aos antimicrobianos foi testada por difusäo do disco e diluiçäo em meio sólido. O sorotipo b foi testado por coaglutinaçäo. Resultados: De 245 H. influenzae identificados, 155 foram testados para o sorotipo b e 28 por cento (43/155) mostraram-se positivos...

In vitro activity of BMY-28100, a new oral cephalosporin.

BMY-28100 is a new orally absorbed cephalosporin whose in vitro activity was compared with that of cefaclor. BMY-28100 was more active against Staphylococcus aureus and Haemophilus influenzae than was cefaclor. In addition, there was only a small rise in MIC50 and MIC90 values for BMY-28100 when the inoculum size was increased 100- or 10,000-fold. In contrast, MIC50 and MIC90 values increased significantly for cefaclor with similar increases in inoculum size. These data suggest that BMY-28100 may be a promising agent to test for oral administration in infections caused by S. aureus and H. influenzae.