***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: INTRODUCTION The extrusion of irrigation solutions beyond the apical constriction may result in postoperative pain .  Sodium hypochlorite can cause severe tissue irritation and necrosis outside the root canal system if extruded into the periodontal ligament ( PDL ) space . Different delivery techniques were discussed to reduce this potential risk . The aim of this study was to compare the postoperative level of pain after root canal therapy using either endodontic needle irrigation or a negative apical pressure device . MATERIAL AND METHODS In a prospect i ve r and omized clinical trial , 110 asymptomatic single-rooted anterior and premolar teeth were treated endodontically with two different irrigation techniques . The teeth were r and omly assigned to two groups . In the MP group ( n = 55 ) , procedures were performed using an endodontic irrigating syringe ( Max-i-Probe ; Dentsply Rinn , Elgin , IL ) . The EV group ( n = 55 ) used an irrigation device based on negative apical pressure ( EndoVac ; Discus Dental , Culver City , CA ) . Postoperatively , the patients were prescribed ibuprofen 200 mg to take every 8 hours if required . Pain levels were assessed by an analog scale question naire after 4 , 24 , and 48 hours . The amount of ibuprofen taken was recorded at the same time intervals . RESULTS During the 0- to 4- , 4- to 24- , and 24- to 48-hour intervals after treatment , the pain experience with the negative apical pressure device was significantly lower than when using the needle irrigation ( p < 0.0001 [ 4 , 24 , 48 hours ] ) . Between 0 and 4 and 4 and 24 hours , the intake of analgesics was significantly lower in the group treated by the negative apical pressure device ( p < 0.0001 [ 0 - 4 hours ] , p = 0.001 [ 4 - 24 hours ] ) . The difference for the 24- to 48-hour period was not statistically different ( p = 0.08 ) . The Pearson correlation coefficient revealed a strongly positive and significant relationship for the MP group ( r = 0.851 , p < 0.001 ) and the EV group ( r = 0.596 , p < 0.0001 ) between pain intensity and the amount of analgesics . CONCLUSION The outcome of this investigation indicates that the use of a negative apical pressure irrigation device can result in a significant reduction of postoperative pain levels in comparison to conventional needle irrigation 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 Irrigation of root canals during endodontic therapy is an important step . Sodium hypochlorite ( NaOCl ) , hydrogen peroxide ( H2O2 ) , chlorhexidine ( CHX ) and normal saline are commonly used intracanal irrigants to disinfect and clean the root canals . This prospect i ve study was set to observe the efficacy of normal saline ( 0.9 % NaCl ) irrigation with sequential irrigation of 3 % H2O2 , 5.2 % NaOCl and 0.9 % NaCl .  A total number of 228 dental patients were screened and 104 patients fulfilling the inclusion criteria were enrolled for the endodontic therapy of mature permanent teeth for the period of one year . Two treatment groups were constituted in which patients were r and omly allocated equally in each treatment group . Post-obturation pain , swelling , analgesic use and eight weeks post-obturation radiological evaluation of the patients were carried out as the measurement of clinical and radiological success of the endodontic treatment . No statistically significant differences were observed in the measured treatment outcomes between two groups . However , studies involving larger sample size and longer post-obturation follow up are recommended for the further either confirmation or rejection of present findings OBJECTIVE The purpose of this study was to establish whether addition of a 2 % chlorhexidine rinse to a conventional treatment protocol enhances the rate of the successful disinfection of the root canal system in vivo . STUDY DESIGN Twenty-four teeth with infected necrotic pulps and resorbing apical periodontitis were treated with a conventional technique in which 1 % NaOCl as irrigant was used . Half of the cases received an additional rinse with 2 % chlorhexidine . Prereduced thioglycollate medium was used to take cultures that were incubated for 4 weeks . RESULTS Cultivable bacteria were retrieved at the conclusion of the first visit in 1 out of 12 chlorhexidine cases whereas in the control group 7 out of 12 cases showed growth . This difference was significant ( P < .05 ) . CONCLUSION The findings are clinical ly important AIM The purpose of this study was to compare the patient 's postoperative discomfort when  root canal irrigation was performed either with st and ard sodium hypochlorite or with sodium hypochlorite with the adjunct of a proteolytic enzyme . METHODS Two hundred patients were endodontically treated in two clinics . The type of irrigant to be used during root canal instrumentation was r and omly assigned . Final irrigation was done using EDTA 17 % . The canals were filled by warm vertical condensation with guttha-percha and the coronal seal was made using IRM . Patients were given a question naire to assess pain and swelling and the number of analgesics and other drugs taken during the first week after treatment . RESULTS A total of 166 question naires could have been evaluated . No significant difference was found between groups for pain , swelling and analgesics taken . Moderate pain and swelling was reported only in the first two days after treatment . No antibiotics use was reported . No guttha-percha excess beyond root apex was found by radiographic assessment . CONCLUSIONS The irrigating solution containing a proteolytic enzyme does not produce greater postoperative discomfort as compared to the conventional sodium hypochlorite in patients undergoing endodontic therapy Four common oral analgesics were tested in a single-blind trial to determine their relative efficacy in the management of postsurgical pain in 103 patients who had their impacted third molars surgically removed under general anesthesia . The analgesics tested were acetylsalicylic acid ( 26 patients ) , ibuprofen ( 26 patients ) , a paracetamol/codeine/caffeine combination ( Solpadeine ) ( 25 patients ) , and dihydrocodeine ( 26 patients ) . The paracetamol/codeine/caffeine combination , ibuprofen , and acetylsalicylic acid preparations produced equally effective analgesia .  Dihydrocodeine was found to be a poor analgesic in this pain model . There were no adverse reactions to any of the preparations 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 purpose of this study was to compare levels of postoperative discomfort after cleaning and shaping of root canals using two protocol s for removal of smear layer . Seventy-three consecutive patients requiring root canal treatment were included . At r and om , canals were cleaned and shaped with one of the following protocol s. In group 1 , 5.25 % sodium hypochlorite was used as the root canal irrigant . The smear layer was removed by placing 17 % EDTA in the canal(s ) for 1 min followed by a 5-ml rinse with 5.25 % NaOCl . In group 2 , canals were irrigated with 1.3 % NaOCl ; the smear layer was removed by placing MTAD in the canal(s ) for 5 min . Access cavities were closed with a sterile cotton pellet and Cavit . The patients recorded degree of discomfort at various time intervals after cleaning and shaping on a visual analogue scale for 1 wk . No significant statistical difference was found in the degree of discomfort between the two groups ( p = 0.58 ) In this study , the antibacterial activity of the different antibacterial solutions using as root canal irrigant was compared in the teeth with pulpal necrosis and with periapical pathosis . Thirty root canals of incisors and premolars of 20 patients were used . Before and after the root canal preparation , two canal sample s were obtained by a harvesting method using a sterile paper point in the first appointment . During the biomechanical preparation , both irrigant solutions were used for each tooth which were r and omly divided into two groups . Last sample s were also obtained before the root filling procedure . Sample s obtained from the root canals were subjected to microbiologic processing , including anaerobic incubation on trypticase soy agar for 5 to 7 days . After counting of CFU on the plates , we concluded that both chlorhexidine gluconate and sodium hypochlorite were significantly effective to reduce the microorganisms in the teeth with necrotic pulp , periapical pathologies , or both , and could be used successfully as an irrigant solution AIM To compare the levels of postoperative pain after cleaning and shaping of root canals using two different root canal irrigants for debridement . MATERIAL S AND METHODS Forty patients with irreversible pulpitis , pulp necrosis and non-vital teeth exhibiting acute apical periodontitis requiring root canal treatment were included . At r and om , canals were cleaned and shaped with the following protocol s. 2 % chlorhexidine solution in group I and 5.25 % sodium hypochlorite solution in group II were used as an irrigants . Access cavities were closed with a sterile cotton pellet and cavit . The patients recorded degree of pain at various time intervals after cleaning and shaping on a visual analogue scale for 1 week . RESULTS The mean pain score for group I was between 0.65 and 3.35 and for group II was between 0.95 and 4.50 . There was significant difference in the pain level between the two groups only at 6 th hour postoperatively ( P<0.05 ) and the pain was more in sodium hypochlorite group . CONCLUSIONS More pain was present in teeth irrigated using 5.25 % sodium hypochlorite when compared to that in teeth irrigated using 2 % chlorhexidine solution . Significant difference in pain level was present only at 6th hour postoperatively , and at all other periods ( 24 th hour , 4 th and 7 th days ) there was no significant difference in pain level between the two groups Objective To compare the effect of a combination of 20 % citric acid solution and photo-activated disinfection with the use of 20 % citric acid and 2.25 % sodium hypochlorite solutions on bacterial load on the dentine walls in prepared canals in vivo . Subjects and methods Sixty-four r and omly selected cases were evaluated and allocated to one of two groups . In Group 1 , after gaining access to the root canal , bacterial load on the canal walls was sample d using endodontic files . A further sample was taken after apex location and initial widening of the canal had been completed and the photo-activated disinfection process carried out . A final sample was taken after completion of the canal preparation using citric acid and sodium hypochlorite solutions . In Group 2 , the initial sample was taken as described previously . A second sample was taken after conventional preparation using 20 % citric acid and sodium hypochlorite solutions as co-irrigants . A final sample was then taken after a subsequent PAD treatment . All sample s were cultured for facultative anaerobic bacteria . Results Of the canals treated in Group 1 only two of the 2 
    Output:
    
There is currently insufficient reliable evidence showing the superiority of any one individual irrigant .
The strength and reliability of the supporting evidence was variable and clinicians should be aware that changes in bacterial counts or pain in the early postoperative period may not be accurate indicators of long-term success .