Comparison of the effect of calcium hydroxide and chlorhexidine 2% gel on bacterial contamination of post space

 One of the most important problems after post space preparation is its bacterial contamination especially before post placement and its effect on overall treatment success and incidence of dental infections. So the purpose of this study was to compare the effect of calcium hydroxide and chlorhexidine 2% gel on bacterial contamination of post space.
Material and  This study was a clinical trial (IRCT2017041232777N1)  and was performed as single blinded randomized clinical trial. 45 maxillary incisors from 23 Patients which were corresponded with inclusion criteria were selected and included. After access preparation and WL determination, canals were prepared with Mtwo rotary files till 35/0.06.Sodium hypochlorite was used as irrigant. Finally EDTA was applied to remove smear layer. Canals were obturated by lateral obturation technique with AH26.After post space preparation first sampling was taken and CFU was determined.       Then sampled were randomly divided into first experimental group was calcium hydroxide and the second was chlorhexidine 2% gel.The control group had not delivered any medicament. Then teeth were temporized with Cavisol and after two weeks by discharging and neutralizing the medicaments the second sampling was done .then the change of CFU of bacteria was compared using ANOVA test, also TAMHANE test was used to compare groups two by two.  In control group s.mutans after two weeks had increased 21%. In calcium hydroxide group these bacteies had decreased with the amount of 34 % and in chlorhexidine group this decrease was 17 % (p<0.001). So the most effective medicament against S.mutans was calcium hydroxide. For E.faecalis in control group after two weeks had increased 400 %. In calcium hydroxide group these bacteies had decreased with the amount 35% and in chlorhexidine group this decrease was 98 % (p<0.001). It was seems that calcium hydroxide has better efficacy on S,mutans and Chlorhexidine has better efficacy on E.faecalis bacteria in dental post spaces.