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.
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
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 ) .