Microbiological evaluation of clindamycin as a root canal dressing in teeth with apical periodontitis. Isolation of yeasts and enteric bacteria in root-filled teeth with chronic apical periodontitis. Clinical efficacy of treatment procedures in endodontic infection control and one year follow-up of periapical healing. Prevention of the ingress of a known virulent bacterium into the root canal system by intracanal medications. The relationship of intracanal medicaments to postoperative pain in endodontics. Outcome of one-visit and two-visit endodontic treatment of necrotic teeth with apical periodontitis: a randomized controlled trial with one-year evaluation. Influence of calcium hydroxide intracanal dressings on the prognosis of teeth with endodontically induced periapical lesions. Reduction in intracanal bacteria during root canal preparation with and without apical enlargement. Antibacterial efficacy of MTAD final rinse and two percent chlorhexidine gel medication in teeth with apical periodontitis: a randomized double-blinded clinical trial. Microbiological evaluation of different irrigation protocols on root canal disinfection in teeth with apical periodontitis: an in vivo study. Ability of chemomechanical preparation with either rotary instruments or self-adjusting file to disinfect oval-shaped root canals. Effects of instrumentation, irrigation and dressing with calcium hydroxide on infection in pulpless teeth with periapical bone lesions. Tissue response to root canal irrigation systems in dogs’ teeth with apical periodontitis Antimicrobial effectiveness of intracanal medicaments on Enterococcus faecalis: chlorhexidine versus octenidine. Postoperative pain after endodontic retreatment: single- versus two-visit treatment. Antimicrobial effect of 0.2% chlorhexidine in infected root canals. Intracanal medications versus placebo in reducing postoperative endodontic pain--a double-blind randomized clinical trial. One visit apicectomy technique using calcium hydroxide cement as the canal filling material combined with retrograde amalgam. The effect of smear layer on microbial coronal leakage of gutta-percha root fillings. Investigation of pH at different dentinal sites after placement of calcium hydroxide dressing by two methods. Microbiological evaluation of one- and two-visit endodontic treatment of teeth with apical periodontitis: a randomized, clinical trial. Periapical healing of endodontically treated teeth in one and two visits obturated in the presence or absence of detectable microorganisms. Influence of an apical negative pressure irrigation system on bacterial elimination during endodontic therapy: a prospective randomized clinical study.
The present investigation was design ed to study the effect of clindamycin on  root canal infection  when placed as an intracanal dressing . Twenty-five teeth with necrotic pulps and periapical radiolucencies were included . Following initial bacteriological sampling and routine instrumentation , clindamycin powder mixed to a paste with saline was applied for 14 days . The presence or absence of bacteria was determined in sample s taken immediately after removal of the dressing , and after a period of 7 days during which the canals were filled with sampling fluid . Bacteria were recovered from four and six teeth respectively . The results indicated that clindamycin offered no advantage over conventional root canal dressings , such as calcium hydroxide , and it is therefore not recommended for use in routine endodontic therapy AIMS The aim of this study was to determine the occurrence and role of yeasts , enteric gram-negative rods and Enterococcus species in root-filled teeth with chronic apical periodontitis , and the antimicrobial effect of iodine potassium iodide ( IKI ) irrigation . METHODOLOGY Forty symptom-free root-filled teeth with chronic apical periodontitis were included in the study . The patients were divided into two groups . In group A the canals were filled with calcium hydroxide for 10 - 14 days after cleaning and shaping ; in group B the canals were irrigated with IKI for 5 min after cleaning and shaping followed by a permanent root filling . Microbiological sample s were taken from the canals before and after the chemomechanical preparation and after iodine irrigation ( group B ) . RESULTS Microbes were isolated from 33 of 40 teeth in the initial sampling . Yeasts were isolated from six teeth , three of them together with E. faecalis . Enteric rods ( Escherichia coli , Klebsiella pneumoniae and Proteus mirabilis ) were present in three teeth and E. faecalis was isolated from 21 of the 33 culture positive teeth , 11 in pure culture . Growth was detected in 10 teeth of the second sample s. Six of the 10 cases were E. faecalis , with five being a pure culture . All third sample s ( after IKI ) except one were negative . The number of microbial cells per sample did not correlate with lesion size . Two flare-ups were recorded , both in teeth with a mixed infection . CONCLUSION The high prevalence of enteric bacteria and yeasts in root-filled teeth with chronic apical periodontitis was established . IKI improved the antimicrobial effect of the treatment The objective was to evaluate the clinical efficacy of chemomechanical preparation of the root canals with sodium hypochlorite and interappointment medication with calcium hydroxide in the control of root canal infection and healing of periapical lesions .  Fifty teeth diagnosed with chronic apical periodontitis were r and omly allocated to one of three treatments : Single visit ( SV group , n = 20 ) , calcium hydroxide for one week ( CH group n = 18 ) , or leaving the canal empty but sealed for one week ( EC group , n = 12 ) . Microbiological sample s were taken to monitor the infection during treatment . Periapical healing was controlled radiographically following the change in the periapical index at 52 wk and analyzed using one-way ANOVA . All cases showed microbiological growth in the beginning of the treatment . After mechanical preparation and irrigation with sodium hypochlorite in the first appointment , 20 to 33 % of the cases showed growth . At the second appointment 33 % of the cases in the CH group revealed bacteria , whereas the EC group showed remarkably more culture positive cases ( 67 % ) .  Sodium hypochlorite  was effective also at the second appointment and only two teeth remained culture positive . Only minor differences in periapical healing were observed between the treatment groups . However , bacterial growth at the second appointment had a significant negative impact on healing of the periapical lesion ( p < 0.01 ) . The present study indicates good clinical efficacy of sodium hypochlorite irrigation in the control of root canal infection . Calcium hydroxide dressing between the appointments did not show the expected effect in disinfection the root canal system and treatment outcome , indicating the need to develop more efficient inter-appointment dressings Contamination of the root canal system by persistent , enteric bacteria via leakage through interim restorations has been well documented . This in vitro study evaluated the ability of interappointment medications to prevent contamination of the root canal system by Enterococcus faecalis . Coronally unsealed , medicated tooth roots fixed in a closed system were contaminated daily with a st and ardized , aerobic , broth culture of E. faecalis . Four medications were evaluated ( n = 15 ) : group A , calcium hydroxide/methylcellulose paste ; group B , camphorated parachlorophenol/calcium hydroxide paste ; group C , 1 % chlorhexidine/methylcellulose gel ; and group D , calcium hydroxide points . The mean number of days to contamination as indicated by turbidity in the closed system was the following : group A , 37 ; group B , 46 ; group C , 16 ; group D , 5 ; and a positive control ( no medication ) , 3 . A one-way analysis of variance with a Scheffe post hoc test ( p = 0.05 ) detected significant differences in effectiveness with A and B superior to C and D , and C superior to AIM To investigate the relationship of postoperative pain to three different medicaments placed in the root canal after a complete biomechanical debridement of the root canal system in patients presenting for emergency relief of pain . METHODOLOGY Two hundred and twenty-three teeth belonging to 221 patients presenting as emergencies to the Royal Dental Hospital of Melbourne were included in the study . Inclusion was limited to patients with a diagnosis of pulp necrosis and acute apical periodontitis . All teeth underwent conventional root canal treatment  , which involved the instrumentation to the apices of each canal at the first visit . Canals were instrumented using a stepback technique and h and -files along with irrigants using Milton 's ( 1 % sodium hypochlorite ) solution followed by 15 % EDTAC . The canals were dried and one of the following three medicaments was inserted into the canal in r and om sequence : Group 1 : Ledermix paste ( Lederle Pharmaceuticals , Division of Cyanamid , Wolfratshausen , Germany ) ; Group 2 : calcium hydroxide paste ( Calcipulpe , Septodont , France ) ; and Group 3 : no dressing . Before dismissal , the preoperative pain experienced on the previous night was recorded using a visual analogue pain scale . Patients were then instructed to record the degree of pain experienced 4 h after treatment and daily for a further 4 days . RESULTS The mean score pain for all three groups was between 42 and 48 prior to treatment being commenced . After 4 days , the pain score for Group 2 was 10 , for Group 3 was 7 and for Group 1 was 4 . Mean preoperative pain level was 44.4 ( of a maximum 100 ) for all groups , and declined by 50 % ( to 22.1 ) after 24 h. Patients in Group 1 ( Ledermix ) experienced significantly less ( P = 0.04 ) postoperative pain than those in the other two groups . There was no significant difference between Group 2 ( calcium hydroxide ) and Group 3 ( no dressing ) . CONCLUSION Under the conditions of this study , painful teeth with acute apical periodontitis that had been dressed with Ledermix paste gave rise to less pain than that experienced by patients who had a dressing of calcium hydroxide or no dressing at all . Ledermix is an effective intracanal medicament for the control of postoperative pain associated with acute apical periodontitis , with a rapid onset of pain reduction The choice of one-visit versus two-visit root canal therapy for necrotic teeth with apical periodontitis is a source of current debate . The primary objective of this r and omized controlled clinical trial was to compare radiographic evidence of periapical healing after root canal therapy completed in one visit or two visits with an interim calcium hydroxide/chlorhexidine paste dressing .  Ninety-seven patients met the inclusion criteria and consented to participate in this study . Patients were r and omly assigned to either the one-visit or two-visit group , and root canal therapy was performed with a st and ardized protocol . Patients in the two-visit group received an intracanal dressing of calcium hydroxide/chlorhexidine paste . Sixty-three patients , 33 in the one-visit group and 30 in the two-visit group , were evaluated at 12 months . The primary outcome measure was change in apical bone density by using the periapical index ( PAI ) . Secondary outcome measures were proportion of teeth healed or improved in each group . Both groups exhibited equally favorable periapical healing at 12 months , with no statistically significant differences between groups AIM This prospect i ve clinical study explored the influence of calcium hydroxide as an interappointment dressing on the healing of periapical lesions associated with pulpless teeth that had not been endodontically treated previously . This was achieved by comparing the prognosis after a two-visit root canal treatment with that following a one-visit treatment . METHODOLOGY Seventy-three patients were recruited having one tooth with an endodontically induced lesion . Of these patients , 67 could be re-examined .  Calcium hydroxide was placed in the instrumented root canals of 31 teeth for at least one week and the treatment finished at the second visit . Thirty-six teeth were root canal treated at one visit . The criteria for success were the absence of signs and symptoms indicating an acute phase of periapical periodontitis and radiographically a periodontal ligament space of normal width . Methods for event time analysis were used to evaluate and compare the prognosis of both treatment approaches . RESULTS The probability that complete periapical healing will take place increased continuously with the length of the observation period . In both treatment groups the likelihood that the root canal treatment yields a success within an observation time of five years exceeded 90 % . A statistically significant difference between the two treatment groups could not be detected . CONCLUSIONS From a microbiological perspective , one-visit root canal treatment created favourable environmental conditions for periapical repair similar to the two-visit therapy when calcium hydroxide was used as antimicrobial dressing . One-visit root canal treatment is an acceptable alternative to two-visit treatment for pulpless teeth associated with an endodontically induced lesion AIM To compare in vitro intracanal bacterial reduction using nickel-titanium rotary instruments with and without apical enlargement . METHODOLOGY Thirty-eight palatal roots of maxillary molar teeth , with mature apices were subdivided according to lengths and then r and omly assigned to two experimental and one control groups . The roots were sterilized and then reinfected with Enterococcus faecalis , which served as a bacteriological marker . All roots in the experimental groups were prepared in a step-down sequence with engine-driven GT rotary files at 350 rpm . In experimental group A ( n = 16 ) additional apical enlargement to ISO size 35 was performed . In group B ( n = 16 ) a serial step-back technique was followed with no apical enlargement . This was combined in groups A and B with irrigation with NaOCl and EDTA . In the control group ( group C , n = 6 ) irrigation only was carried out , with no mechanical preparation . Sample s were then taken from the root canals to determine the numbers of remaining bacteria . RESULTS In groups A and B , 15 ( 94 % ) and 13 ( 81 % ) specimens were rendered bacteria-free , respectively . In the control group C none of the specimens were bacteria-free . There was a significant difference ( P < 0.001 ) in the antibacterial effects of experimental and control regimens . There was , however , no significant difference ( P = 0.276 ) between the preparation methods used in the experimental groups . CONCLUSIONS There was no significant difference in intracanal bacterial reduction when Ni-Ti GT rotary preparation with NaOCl and EDTA irrigation was used with or without apical enlargement preparation technique . It may therefore not be necessary to remove dentine in the apical part of the root canal when a suitable coronal taper is achieved to allow satisfactory irrigation of the root canal system with antimicrobial agents INTRODUCTION Clinical assessment of the efficacy of novel root canal disinfection protocol s is an important focus in endodontic research . This r and omized double-blinded study assessed the antibacterial efficacy of a final rinse with BioPure MTAD ( MTAD ) and intracanal medication with 2 % chlorhexidine gel ( CHX ) in teeth with apical periodontitis . METHODS Canals in 30 teeth ( single-rooted and multi-rooted ) were prepared by using 1.3 % NaOCl , rinsed with MTAD or saline in r and om sequence , medicated with CHX for 7 days , irrigated with 1.3 % NaOCl , and filled . Bacteriologic root canal sample s were obtained by aspiration before ( 1A ) and after ( 1B ) canal preparation , after the final rinse ( 1C ) , after CHX was flushed ( 2A ) , and after final irrigation ( 2B ) . Bacteria were enumerated by epifluorescence-microscopy ( EFM ) by using 2 staining methods and by colony-forming-unit ( CFU ) counts after 14 days of incubation . RESULTS Bacterial counts ( EFM ) in 1B were greater than 95 % decreased from 1A . Low bacterial densities in 1B , 1C , 2A , and 2B did not differ significantly from each other . EFM counts were consistently higher than CFU counts . CONCLUSIONS The final rinse with MTAD and medication with CHX did not reduce bacterial counts beyond levels achieved by canal preparation with NaOCl The present in vivo study was design ed to evaluate the efficacy of apical negative pressure irrigation ( ANP ) , passive ultrasonic irrigation ( PUI ) and positive pressure irrigation ( PP ) in the reduction of intracanal bacteria of dogs ' teeth with pulp necrosis and apical periodontitis . Eighty root canals were r and omly distributed into 3 experimental and 2 control groups according to the irrigation delivery system : group ANP ( n=20 ) , group PUI ( n=20 ) , group PP ( n=20 ) , group PC ( positive control - sterile saline irrigation ; n=10 ) and group NC ( negative control - vital pulps not subjected to bacterial inoculation ; n=10 ) . The first sample ( S1 ) was collected at baseline , and the second sample ( S2 ) was collected after the disinfection protocol s. All sample s were seeded in culture media for anaerobic bacteria . CFU counts were analyzed statistically by the Kruskal-Wallis , Dwass-Steel-Critchlow-Fligner post-hoc and Chi-square followed by Tukey like multiple comparisons for proportions ( α=0.05 ) . All experimental groups were effective in reducing Gram-positive bacteria compared with PC ( p<0.05 ) . Regarding the reduction of Gram-negative bacteria , group ANP was significantly better than PP ( p<0.05 ) . No statistically significant difference could be found between PP and PUI ( p>0.05 ) . In dog 's teeth with apical periodontitis , the use of ANP and PUI can be considered promising disinfection protocol s as both delivery systems promoted a significant bacterial reduction INTRODUCTION Oval-shaped root canals might represent a great challenge for proper disinfection . This study compared the capability of a newly developed instrument , the self-adjusting file ( SAF ) , and rotary nickel-titanium ( NiTi ) instrumentation to eliminate Enterococcus faecalis population s from long oval root canals of extracted human teeth . As a secondary purpose , the ability of a modification in sampling technique to recover bacteria lodged in recesses of oval canals was evaluated . METHODS Long oval canals from m and ibular incisors and maxillary second premolars were infected with E. faecalis ( ATCC 29212 ) for 30 days and then r and omly distributed into 2 experimental groups . In group 1 , canals were prepared up to a 40/04 rotary BioRaCe instrument by using irrigation with NaviTip needles ; in group 2 , canals were prepared by using the SAF system with continuous irrigation . NaOCl and ethylenediaminetetraacetic acid were used as irrigants . Bacteriologic sample s were taken before ( S1 ) and after preparation ( S2a and S2b ) . RESULTS Reduction in the bacterial population s was highly significant in both groups ( P < .001 ) . Preparation of long oval canals with the SAF was significantly more effective than rotary NiTi instrumentation in reducing intracanal E. faecalis counts ( P = .01 ) . Frequency of positive cultures in S2 sample s was 11 of 20 ( 55 % ) for rotary instrumentation and 4 of 20 ( 20 % ) for SAF instrumentation ( P = .048 ) . S2b sample s ( modified method ) yielded more positive sample s than S2a ( 12/40 vs 5/40 ) , but this difference reached no statistical significance ( P > .05 ) . CONCLUSIONS The SAF system was significantly more effective than rotary NiTi instrumentation used with syringe/needle irrigation in disinfecting long oval root canals in vitro . A modified sampling technique might be necessary for oval canals AIM The aim of this study was to evaluate the fate of microorganisms in root canals of teeth with infected pulps and periapical bone lesions with and without the use of calcium hydroxide medication . METHODOLOGY Endodontic sample s were cultured and microorganisms were counted and identified in 43 teeth before ( sample 1 ) and after ( sample 2 ) treatment during the first visit and before ( sample 3 ) and after ( sample 4 ) treatment during the second visit . In the first visit teeth were instrumented and half of the teeth were filled with a thick slurry of calcium hydroxide in sterile saline . The other teeth were obturated with gutta-percha and AH-2 6 sealer . After 4 weeks the teeth with calcium-hydroxide were accessed again and after microbiological sampling they were obturated with gutta-percha and AH-26 sealer . RESULTS The mean total colony forming unit ( CFU ) counts of positive sample s dropped significantly as a result of canal preparation during the first visit from 1.0 x 10(6 ) to 1.8 x 10(3 ) ( between sample s 1 and 2 ) but increased to 9.3 x 10(3 ) in the period between the two visits ( sample 2 and 3 ) . There was no difference in mean total CFU counts of positive sample s between the end of the first ( sample 2 ) and the end of the second visit ( sample 4 ) . The most frequently isolated species were Prevotella intermedia , Capnocytophaga spp .. Actinomyces odontolyticus . Propionibacterium acnes and Peptostreptococcus micros . CONCLUSIONS Although a calcium hydroxide paste was placed in the prepared canals , the number of positive canals had increased in the period between visits . However , the number of microorganisms had only increased to 0.93 % of the original number of CFU ( sample 1 ) . It is concluded that a calcium hydroxide and sterile saline slurry limits but does not totally prevent regrowth of endodontic bacteria Objectives The aim of this study was to compare the efficacy of apical negative pressure irrigation ( ANP ) and passive ultrasonic irrigation ( PUI ) with apical positive pressure irrigation ( PP — conventional irrigation ) in the periapical repair of dogs ’ teeth with apical periodontitis . Methods Forty-nine mesial and distal root canals of premolars of three dogs with experimentally induced periapical lesions were subjected to a single-session root canal treatment . The teeth were r and omly assigned to three groups : ANP , PUI , and PP ( control ) . After 180 days , the animals were euthanized , and the anatomic pieces were removed and subjected to histotechnical processing for morphological and morphometric histological analyses of hematoxylin and eosin (HE)-stained sections under conventional and fluorescence microscopy . Periapical lesion size before and 180 days after root canal treatment was measured by periapical radiographic examination . Tartrate-resistant acid phosphatase ( TRAP ) histoenzymology was performed for osteoclast counting and Brown and Brenn staining to assess bacteria . Data were analyzed statistically by the Kruskal-Wallis test ( α = 5 % ) . Result There were no statistically significant differences among the groups regarding periapical lesion size in the radiographic evaluation ( p = 0.91 ) . In the comparison of histopathological parameters , group ANP presented more homogeneous results . There was a statistically significant difference ( p = 0.02 ) between groups ANP and PP , with better results for group ANP in which milder infiltrate inflammatory was observed . No statistically significant difference ( p > 0.05 ) was found among the groups with respect to periodontal ligament space , presence of mineralized tissue resorption , size of the periapical lesions , and number of osteoclasts . Conclusion Although the three irrigation systems elicited similar periapical tissue response with respect to almost all evaluated parameters , ANP presented the mildest inflammatory infiltrate , suggesting an advantage over PP in the indication for clinical use . Clinical relevance Irrigation of the root canal systems is an extremely important step in root canal treatment . Therefore , it is of relevance to evaluate the efficacy of these systems by in vivo experimental models to provide scientific background for the clinical practice AIM To determine the viability of Enterococcus faecalis in infected human root dentine in vitro after exposure to root canal medicaments based on chlorhexidine and octenidine . METHODOLOGY Human root segments ( n = 40 ) were infected with E. faecalis for 8 weeks . Root dentine sample s ( rd ) collected at week 4 served as individual baseline values . At week 8 , the root segments were r and omly divided into four test groups ( n = 10 each ) for the placement of one of the following medicaments in the root canals : calcium hydroxide paste ( CH ) , chlorhexidine gel ( CHX-gel ) ( 5.0 % ) , chlorhexidine/gutta-percha points ( CHX-GP ) ( active points ( ® ) ; Roeko , Langenau , Germany ) and octenidine gel ( OCT-gel ) ( 5.0 % ) followed by incubation for 4 weeks . The effect on E. faecalis viability was assessed by two fluorescent dyes ( syto 9/propidium iodide ) to determine the ' proportion of viable bacteria ' ( PVB% ) and number of ' colony-forming units ' ( CFU ) . Mean values and 95 % confidence intervals ( CI ) were calculated for PVB% and log CFU , and the difference between groups was established . RESULTS Viable and dead bacterial cells were detected in all ' rd ' sample s at weeks 4 and 8 . The treatment with CHX-gel , CHX-GP and OCT-gel result ed in significantly lower PVB% values with 15.4 % , 3.5 % and 0 % , respectively . No growth ( CFU ) was recorded for these sample s at week 12 . When medicated by CH , the PVB% was increased without a corresponding change in CFUs . CONCLUSIONS In contrast to calcium hydroxide , both CHX - and octenidine-based intracanal medicaments were effective in decreasing the viability of E. faecalis . OCT showed the most favourable results and may have potential as an endodontic medicament OBJECTIVE The purpose of this clinical study was to determine the effect of 1- or 2-visit root canal treatment on the postoperative pain in the retreatment cases . STUDY DESIGN Two hundred eighteen cases that required retreatment were included in the study . Obturated and unfilled canal space and the status of periapical tissues were evaluated according to the PAI index . The patients were subcategorized in regard to the presence or the absence of preoperative pain . Approximately half of each category was treated in 1 appointment . After removing the previous root canal obturation material s and biomechanic preparation of root canals , the teeth in the 1-visit group were obturated at the first appointment by using AH 26 sealer and laterally compacted gutta-percha , and those in the 2-visit group were medicated with calcium hydroxide-chlorhexidine combination and then closed with a temporary filling material . One week after the initial appointment , patients were asked about the occurrence of postoperative pain . The level of discomfort was rated as no pain , mild pain , moderate pain , or severe pain ( flare-up ) . Data were statistically analyzed using the chi-squared and Fischer exact tests . RESULTS Eight patients from the 1-visit group and 2 patients from the 2-visit group had flare-ups . There was a statistical difference between the groups ( P < .05 ) . Two-visit root canal treatment was more effective in completely eliminating pain than 1-visit treatment of previously symptomatic teeth ( P < .05 ) . CONCLUSIONS Two-visit endodontic treatment with intracanal medication was found to be effective in reducing postoperative pain of previously symptomatic teeth and decreased the number of flare-ups in all retreatment cases The aim of this study was to identify bacteria from the infected root canals of teeth with chronic apical periodontitis , and to evaluate the antibacterial effect of 0.2 % chlorhexidine ( CHX ) , as an irrigant , in reducing the microbial flora 48h after root canal preparation . A total of 44 subjects were r and omly divided in the experimental group and the control group . The first bacterial sample s from all root canals were obtained in the beginning , before any treatment . During mechanical instrumentation , root canals were irrigated three times , with 0.2 % CHX in the experimental group , and with saline solution in the control group . All canals were dried and temporarily sealed with zinc oxide-sulfate cement . After 48 h the second sample s were obtained . Bacterial sample s were subjected to microbiologic processing . The study indicates that 0.2 % CHX is significantly effective in reducing the microbial flora , and could be used as an irrigant solution This prospect i ve r and omized , double-blind factorial study aim ed to compare the efficacy of three different intracanal medicaments with the placebo in controlling the postoperative pain after complete root canal preparation . The study was performed on 64 m and ibular molars of 64 patients with diagnosis of pulp necrosis and acute apical periodontitis . After chemomechanical procedures using the stepback technique and 1 % sodium hypochlorite , the teeth were r and omized into four treatment groups ( n=16 ) . In group I , canals were filled with calcium hydroxide paste mixed with 2 % chlorhexidine gel , group II received 2 % chlorhexidine gel , group III was treated with calcium hydroxide paste , and group IV received no dressing ( control ) . Before dismissal , preoperative pain experience was recorded using a visual analog pain scale . Patients were then instructed to quantify the degree of pain experienced 4h after treatment and daily for a further 24 , 48 , 72 and 96h . Two-way repeated measures ANOVA test and post hoc Tukey 's HSD test revealed that at each time interval groups I and II were significantly more effective in reducing the postoperative pain values than groups III and IV ( p<0.05 ) . Dunnett 's test showed that groups I and II differed significantly from control whereas difference between group III and control was not significant ( p>0.05 ) . Patients with pulp necrosis and acute apical periodontitis that had been dressed with chlorhexidine alone and calcium hydroxide plus chlorhexidine gave rise to less pain than that experienced by patients who had a calcium hydroxide dressing alone or no dressing at all A prospect i ve study was set up to evaluate a one-visit  apicectomy technique . Calcium hydroxide cement was used as the root canal filling material . The calcium hydroxide cement set rapidly and clearly revealed the position , size and outline form of the root canals at the level of resection . This facilitated preparation of the apical cavities to a depth of 3 mm . Each cavity was varnished before placement of the amalgam .  Sixty-eight patients ( 93 teeth ) were included in the study . Five patients ( 8 teeth ) were lost to follow-up . The success rate , based on clinical and radiographic examination after a minimum of 2 years , was 91.8 per cent The aim of this in vitro study was to determine the effect of removal of the smear layer on canal obturation as measured by penetration of bacteria from a coronal direction . One hundred and twenty extracted human teeth with straight , single root canals were decoronated . The canals were prepared using the modified double-flared technique with balanced force under copious irrigation . The apical matrix was prepared to size 40 and apical patency subsequently confirmed with a size 15 file . The teeth were divided r and omly into experimental groups ( 80 teeth ) and control groups ( 40 teeth ) . The root canals of 40 experimental and 20 control teeth were rinsed with 40 % citric acid and 2 % NaOCl to remove the smear layer before obturation . In experimental groups , 20 teeth with smear layer intact and 20 teeth with smear layer removed were obturated with lateral condensation of cold gutta-percha and Apexit sealer . A further 20 teeth with smear layer intact and 20 teeth with smear layer removed were obturated with the Trifecta technique with the same sealer . In control groups , 10 teeth with smear layer intact and 10 teeth with smear layer removed were obturated with lateral condensation of cold gutta-percha and Apexit sealer . These teeth were completely sealed both coronally and apically to serve as negative controls . The remaining 20 teeth with either smear layer intact or smear layer removed were not obturated and served as the positive controls . The root surface of each tooth was sealed with nail varnish . The cut end of a polypropylene tube was sealed around the coronal part of each root canal so that bacteria placed therein could move only through the obturated canal space . Each root was placed in a glass bottle containing sterile Todd-Hewitt Broth ( THB ) and aliquots of 0.5 ml of THB were injected into the polypropylene tube . The model system was centrifuged at 168 g. An innoculum of Streptococcus sanguis in THB was placed in each coronal chamber at 5-day intervals and daily observations were made for bacterial growth in the apical reservoir for 90 days . All positive control teeth showed bacterial penetration within 24 h , while the negative control teeth remained uncontaminated throughout the test period . Leakage through the experimental teeth was variable ranging from 7 to 86 days . There was no statistical significant difference ( P > 0.05 ) in leakage between the obturated canal when the smear layer was either removed or intact OBJECTIVE The dentin pH at different sites following placement of calcium hydroxide paste using 2 different methods was evaluated . STUDY DESIGN One hundred twenty Extracted teeth were instrumented and r and omly divided into 6 different groups . Then they were dressed with calcium hydroxide by 2 different methods using paper points or Lentulo spiral , according to their respective groups , and stored . After the experimental period of time , half of the sample s were cut transversally into slices and the other half split longitudinally and rinsed with distilled water . The dentin pH of cervical , middle , and apical thirds was measured from the root canal wall surface and 1 mm away from the root canal lumen in the inner dentin . The results were compared and statistically analyzed . RESULTS The highest pH values were obtained on the root canal walls when the calcium hydroxide was placed with Lentulo spiral filler ( P > .05 ) . There was a significant reduction in pH values in the inner dentin . When the cross sections of teeth were compared at 7 days , the Lentulo group was statistically different only in the apical third . CONCLUSIONS Placement of the calcium hydroxide paste with a Lentulo spiral with subsequent compaction with the blunt end of a sterile paper point obtained a higher pH value on the canal walls and in the inner dentin than paper points only The antimicrobial efficacy of endodontic procedures performed in one-visit ( including a 10-min intraappointment dressing with 5 % iodine-potassium-iodide ) was compared with a two-visit procedure ( including an interappointment dressing with calcium-hydroxide paste ) . Teeth with apical periodontitis ( n = 96 ) were r and omly assigned to either group .  Root canal sampling and culturing  were performed before and immediately after instrumentation , and after medication . Initial sampling demonstrated the presence of microorganisms in 98 % of the teeth . Postinstrumentation sampling showed reduction of cultivable microbiota . Antibacterial dressing further reduced the number of teeth with surviving microbes . In the postmedication sample s , residual microorganisms were recovered in 29 % of the one-visit teeth and in 36 % of the two-visit treated teeth . No statistically significant differences between the groups were discerned . It was concluded that from a microbiological point of view , treatment of teeth with apical periodontitis performed in two appointments was not more effective than the investigated one-visit procedure AIM The purpose of the present study is to evaluate the healing of periapical lesions of teeth with positive and negative canal cultures at the time of obturation , and to evaluate the periapical healing of teeth treated in one visit ( without ) or in two visits with an interappointment dressing of calcium hydroxide . METHODOLOGY Thirty-nine patients received root-canal treatment .  In the first visit , teeth were instrumented , and 18 of these teeth were filled ( after microbiological sampling ) with calcium hydroxide in sterile saline . The other 21 teeth were obturated with gutta-percha and AH-26 sealer after microbiological sampling . Four weeks later , the teeth with calcium hydroxide were accessed again and after microbiological sampling they were obturated with gutta-percha and AH-26 sealer .  Healing of periapical radiolucency was recorded over a period up to 4.5 years . RESULTS In both the treatment groups , the size of the periapical lesions reduced significantly during the follow-up period . Complete radiographic healing was observed in 81 % of the cases in the one-visit group , and in 71 % of the cases in the two-visit group . The probability of success increased continuously over time for both treatment groups . Seven out of eight cases ( 87.5 % ) that showed a positive root-canal culture at the time of obturation healed . The number of colony forming units ( CFU ) in six out of eight positive canals was < 10(2 ) CFU mL(-1 ) . CONCLUSIONS Within the limitations of this study , no significant differences in healing of periapical radiolucency was observed between teeth that were treated in one visit ( without ) and two visits with inclusion of calcium hydroxide for 4 weeks . The presence of a positive bacterial culture ( CFU<10(2 ) ) at the time of filling did not influence the outcome of treatment INTRODUCTION Recent in vitro studies that use an apical negative pressure irrigation system , EndoVac , have demonstrated promising results in the production of debris-free root canals , while also preventing potential extrusion of irrigants into the periapical region . We conducted a r and omized , controlled , prospect i ve clinical study to determine whether the use of EndoVac irrigation ( EndoVac group ) was more efficient compared with st and ard needle irrigation ( control group ) in obtaining canals from which microbes could not be cultivated . METHODS Routine endodontic therapy was performed in 48 patients with necrotic , single-rooted , single-canal teeth . The patients were r and omly assigned to either the EndoVac group ( n = 25 ) or control group ( n = 23 ) . Irrigation with either method was carried out with 0.5 % sodium hypochlorite . After surface disinfection , before instrumentation and on completion of chemomechanical preparation , intracanal microbial sample s were obtained and cultured under anaerobic conditions . The frequency of microbial cultivability by using either irrigation system was analyzed . RESULTS The frequency of obtaining culture-negative root canals was 90.9 % and 82.6 % for the control group and EndoVac group , respectively . There was no significant difference in the antimicrobial efficacy of either control group or EndoVac group ( Fisher exact test , P = .665 ) . Furthermore , no significant association between study variables and the irrigation systems ' antimicrobial efficacy was found ( P > .05 ) . CONCLUSIONS The results of this prospect i ve in vivo study demonstrate that the antimicrobial efficacy of EndoVac irrigation is comparable to that of st and ard irrigation
Calcium hydroxide has limited effectiveness in eliminating bacteria from human root canal when assessed by culture techniques
AIM To determine to what extent does calcium hydroxide intracanal medication eliminate bacteria from human root canals , compared with the same canals before medication , as measured by the number of positive cultures , in patients undergoing root canal treatment for apical periodontitis ( teeth with an infected root canal system ) .