In vivo antibacterial efficacy of 1%chlorhexidine gel as intracanal medication

Objective:Evaluate antibacterial efficacy of 1%chlorhexidine gel(CHX) as intracanal medication in necrotic primary molars, compared to a combination of calcium hydroxide+camphorated paramonochlorophenol(Ca(OH)2+CPMC) in a randomized, blind, split-mouth clinical trial. Methods:Ten healthy, 4-8-year old children with 2 necrotic primary molars were selected to participate in the study. Twenty teeth were randomly divided into 2 different groups, which received either Ca(OH)2+CPMC(CallenPMCC®)(G1) or CHX(G2). All participants received both treatments. Each tooth was anesthetized and isolated with a rubber dam. Pulp chambers were accessed and initial microbiological samples were immediately collected using sterile size-15 paper-point that was kept in place for 60 seconds and transferred to a test tube containing RTF. Instrumentation-irrigation was performed using Sodium Hypochloride, root canals were dried and filled with the selected medication, teeth were temporarily sealed with glass ionomer. After 14-days root canals were re-opened following the same protocol and medication was removed. Root canals were left empty and teeth were temporarily restored. After 48-hours a second sample was collected as previously described. For detection of mutans streptococci(MS), samples were diluted, plated on MSB medium, incubated at 37^oC, during 48-hours, under microaerofilic conditions. For anaerobic bacteria detection, samples were plated on Brucella-blood-agar, incubated for 7 days in anaerobic jars. Bacterial counts were expressed as CFU/mL. To reduce asymmetries, data was converted to natural logarithm for statistical analysis. Results:When comparing initial versus final anaerobe levels in G1(9.96±2.45 versus 6.57±3.84,Paired t-test, p=0.024) and G2(11.21 versus 8.75, Wilcoxon test,p=0.020), treatments were equally effective(p=0.88).G1 did not significantly reduce MS(4.39±4.12 versus 4.52±4.76,Paired t-test,p=0.94),but G2 caused significant MS reduction(7.77±4.47 versus 4.07±4.75,Paired t-test,p=0.002). Conclusion:Ca(OH)2+CPMC was ineffective against MS and 1%CHX gel demonstrated great efficacy in the reduction of anaerobes and MS in root canals of necrotic primary molars. This work was approved by Federal University of Ceara(Brazil) Ethics Committee and was partly funded by FUNCAP(Brazil).