human
***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 INTRODUCTION The purpose of this investigation was to determine the effect that apical preparation size and preparation taper had on the volume of irrigant delivered to the working length of a root canal preparation in a clinical ly relevant amount of time . METHODS Forty intact human single-rooted teeth were r and omly distributed into 2 separate phases . The first phase aim ed to determine the smaller apical size that will allow more volume of irrigant at working length . All sample s had the same taper and were sequentially instrumented to sizes of 30.06 , 35.06 , 40.06 , and 45.06 . The second phase aim ed to determine the taper that will allow more volume of irrigant at working length . Teeth were sequentially instrumented to 40.02 , 40.04 , 40.06 , and 40.08 . All sample s were irrigated by using the micro-cannula , and the volume of sodium hypochlorite suctioned at working length under negative pressure was measured during a period of 30 seconds by using a custom recovery device . RESULTS An increase in size from ISO # 35 to ISO # 40 result ed in a percentage gain of approximately 44 % in mean irrigant volume , whereas an increase in size from ISO # 40 to ISO # 45 result ed in a percentage gain of approximately 4 % . An increase in taper from 0.02 through 0.08 result ed in percentage gains of approximately 74 % , 5.4 % , and 2.4 % increase , respectively . CONCLUSIONS The data demonstrated that an increase in apical preparation size and taper result ed in a statistically significant increase in the volume of irrigant . In addition , an apical enlargement to ISO # 40 with a 0.04 taper will allow for tooth structure preservation and maximum volume of irrigation at the apical third when using the apical negative pressure irrigation system INTRODUCTION Several irrigation techniques have been recently introduced with the main objective of improving root canal disinfection . This in vitro study aim ed at comparing the intracanal bacterial reduction promoted by chemomechanical preparation with 3 different irrigation techniques . METHODS Root canals from extracted teeth were contaminated with Enterococcus faecalis ATCC 29212 for 7 days and then r and omly distributed into 3 experimental groups of 20 teeth each : group 1 , conventional irrigation with NaviTip needles inserted up to 3 mm short of the working length ; group 2 , same as group 1 , but supplemented with final irrigant activation by the EndoActivator system ; and group 3 , irrigation with the EndoVac system . NaOCl and ethylenediaminetetraacetic acid ( EDTA ) were the irrigants used in all experimental groups . The overall preparation time was kept constant for the groups , but the total volume ranged from 20 mL ( groups 1 and 2 ) to 43 mL ( group 3 ) . The control group was irrigated with saline solution ( total volume , 43 mL ) . Sample s taken before and after chemomechanical procedures were cultured , and the colony-forming units ( CFUs ) were counted . RESULTS Reduction in the bacterial population s was highly significant for all groups . The 3 experimental groups with NaOCl and EDTA as irrigants were significantly more effective than the control group with saline in reducing CFU counts . There were no significant differences between the 3 techniques tested . CONCLUSIONS There was no evident antibacterial superiority of any of the irrigation techniques evaluated in the present in vitro model R and omized controlled clinical trials are conducted to determine whether differences of clinical importance exist between selected treatment regimens . When statistical analysis of the study data finds a P value greater than 5 % , it is convention to deem the assessed difference nonsignificant . Just because convention dictates that such study findings be termed nonsignificant , or negative , however , it does not necessarily follow that the study found nothing of clinical importance . Subject sample s used in controlled trials tend to be too small . The studies therefore lack the necessary power to detect real , and clinical ly worthwhile , differences in treatment . Freiman et al. found that only 30 % of a sample of 71 trials published in the New Engl and Journal of Medicine in 1978 - 79 with a P value greater than 10 % were large enough to have a 90 % chance of detecting even a 50 % difference in the effectiveness of the treatments being compared , and they found no improvement in a similar sample of trials published in 1988 . It is therefore wrong and unwise to interpret so many negative trials as providing evidence of the ineffectiveness of new treatments . One must instead seriously question whether the absence of evidence is a valid justification for inaction . Efforts must be made to look for quantification of an association rather than just a P value , especially when the risks under investigation are small . The authors cite a recent trial comparing octreotide and sclerotherapy in patients with variceal bleeding  , as well as the overview of clinical trials evaluating fibrinolytic treatment for preventing reinfa rct ion after acute myocardial infa rct ion as examples INTRODUCTION This study evaluated the prepared surface areas of oval-shaped canals in distal roots of m and ibular molars using four different instrumentation techniques . METHODS Teeth were prescanned and reconstructed using micro-computed tomography ( MCT ) scans at low resolution ( 68 microm ) . Forty-eight molars with ribbon-shaped/oval distal root canals were selected and r and omly assigned to four groups . Distal canals ( n = 12 each ) were prepared by circumferential filing using Hedström files to apical size # 40 ( group H/CF ) ; with ProTaper nickel-titanium rotaries to finishing file 4 ( F4 ) considering the distal canal as 1 canal ( group PT/1 ) ; ProTaper to F4 considering buccal and oral aspects of the distal canal as 2 individual canals ( group PT/2 ) ; ProTaper to F4 in a circumferential filing motion ( PT/CF ) . Before and after shaping , teeth were evaluated using MCT at 34-microm resolution . The percentage of prepared surface was assessed for the full canal length and the apical 4 mm . Statistical analysis was performed using analysis of variance and Bonferroni/Dunn multiple comparisons . RESULTS Preoperatively , canal anatomy was statistically similar among the groups ( p = 0.56 ) . Mean ( + /- st and ard deviation ) untreated areas ranged from 59.6 % ( + /-14.9 , group PT/2 ) to 79.9 % ( + /-10.3 , PT/1 ) for the total canal length and 65.2 % to 74.7 % for the apical canal portion , respectively . Canals in group PT/1 had greater untreated surface areas ( p < 0.01 ) than groups PT/2 and PT/CF . Among all groups , amounts of treated surface areas were statistically similar in the apical 4 mm . CONCLUSIONS Preparations of oval-shaped root canals in m and ibular molars left a variable portion of surface area unprepared regardless of the instrumentation technique used . However , considering oval canals as two separate entities during preparation appeared to be beneficial in increasing overall prepared surface 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 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 INTRODUCTION The purpose of this study was to evaluate the canal isthmus debridement efficacy of a new modified EndoVac ( Discus Dental , Culver City , CA ) irrigation protocol in comparison with EndoVac , passive 
    Output:
    
agent
Inconclusive results were reported about the cleaning and disinfection accomplished by the two irrigation methods .
There is insufficient evidence to cl aim general superiority of any one of these methods .
***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 INTRODUCTION The purpose of this investigation was to determine the effect that apical preparation size and preparation taper had on the volume of irrigant delivered to the working length of a root canal preparation in a clinical ly relevant amount of time . METHODS Forty intact human single-rooted teeth were r and omly distributed into 2 separate phases . The first phase aim ed to determine the smaller apical size that will allow more volume of irrigant at working length . All sample s had the same taper and were sequentially instrumented to sizes of 30.06 , 35.06 , 40.06 , and 45.06 . The second phase aim ed to determine the taper that will allow more volume of irrigant at working length . Teeth were sequentially instrumented to 40.02 , 40.04 , 40.06 , and 40.08 . All sample s were irrigated by using the micro-cannula , and the volume of sodium hypochlorite suctioned at working length under negative pressure was measured during a period of 30 seconds by using a custom recovery device . RESULTS An increase in size from ISO # 35 to ISO # 40 result ed in a percentage gain of approximately 44 % in mean irrigant volume , whereas an increase in size from ISO # 40 to ISO # 45 result ed in a percentage gain of approximately 4 % . An increase in taper from 0.02 through 0.08 result ed in percentage gains of approximately 74 % , 5.4 % , and 2.4 % increase , respectively . CONCLUSIONS The data demonstrated that an increase in apical preparation size and taper result ed in a statistically significant increase in the volume of irrigant . In addition , an apical enlargement to ISO # 40 with a 0.04 taper will allow for tooth structure preservation and maximum volume of irrigation at the apical third when using the apical negative pressure irrigation system INTRODUCTION Several irrigation techniques have been recently introduced with the main objective of improving root canal disinfection . This in vitro study aim ed at comparing the intracanal bacterial reduction promoted by chemomechanical preparation with 3 different irrigation techniques . METHODS Root canals from extracted teeth were contaminated with Enterococcus faecalis ATCC 29212 for 7 days and then r and omly distributed into 3 experimental groups of 20 teeth each : group 1 , conventional irrigation with NaviTip needles inserted up to 3 mm short of the working length ; group 2 , same as group 1 , but supplemented with final irrigant activation by the EndoActivator system ; and group 3 , irrigation with the EndoVac system . NaOCl and ethylenediaminetetraacetic acid ( EDTA ) were the irrigants used in all experimental groups . The overall preparation time was kept constant for the groups , but the total volume ranged from 20 mL ( groups 1 and 2 ) to 43 mL ( group 3 ) . The control group was irrigated with saline solution ( total volume , 43 mL ) . Sample s taken before and after chemomechanical procedures were cultured , and the colony-forming units ( CFUs ) were counted . RESULTS Reduction in the bacterial population s was highly significant for all groups . The 3 experimental groups with NaOCl and EDTA as irrigants were significantly more effective than the control group with saline in reducing CFU counts . There were no significant differences between the 3 techniques tested . CONCLUSIONS There was no evident antibacterial superiority of any of the irrigation techniques evaluated in the present in vitro model R and omized controlled clinical trials are conducted to determine whether differences of clinical importance exist between selected treatment regimens . When statistical analysis of the study data finds a P value greater than 5 % , it is convention to deem the assessed difference nonsignificant . Just because convention dictates that such study findings be termed nonsignificant , or negative , however , it does not necessarily follow that the study found nothing of clinical importance . Subject sample s used in controlled trials tend to be too small . The studies therefore lack the necessary power to detect real , and clinical ly worthwhile , differences in treatment . Freiman et al. found that only 30 % of a sample of 71 trials published in the New Engl and Journal of Medicine in 1978 - 79 with a P value greater than 10 % were large enough to have a 90 % chance of detecting even a 50 % difference in the effectiveness of the treatments being compared , and they found no improvement in a similar sample of trials published in 1988 . It is therefore wrong and unwise to interpret so many negative trials as providing evidence of the ineffectiveness of new treatments . One must instead seriously question whether the absence of evidence is a valid justification for inaction . Efforts must be made to look for quantification of an association rather than just a P value , especially when the risks under investigation are small . The authors cite a recent trial comparing octreotide and sclerotherapy in patients with variceal bleeding  , as well as the overview of clinical trials evaluating fibrinolytic treatment for preventing reinfa rct ion after acute myocardial infa rct ion as examples INTRODUCTION This study evaluated the prepared surface areas of oval-shaped canals in distal roots of m and ibular molars using four different instrumentation techniques . METHODS Teeth were prescanned and reconstructed using micro-computed tomography ( MCT ) scans at low resolution ( 68 microm ) . Forty-eight molars with ribbon-shaped/oval distal root canals were selected and r and omly assigned to four groups . Distal canals ( n = 12 each ) were prepared by circumferential filing using Hedström files to apical size # 40 ( group H/CF ) ; with ProTaper nickel-titanium rotaries to finishing file 4 ( F4 ) considering the distal canal as 1 canal ( group PT/1 ) ; ProTaper to F4 considering buccal and oral aspects of the distal canal as 2 individual canals ( group PT/2 ) ; ProTaper to F4 in a circumferential filing motion ( PT/CF ) . Before and after shaping , teeth were evaluated using MCT at 34-microm resolution . The percentage of prepared surface was assessed for the full canal length and the apical 4 mm . Statistical analysis was performed using analysis of variance and Bonferroni/Dunn multiple comparisons . RESULTS Preoperatively , canal anatomy was statistically similar among the groups ( p = 0.56 ) . Mean ( + /- st and ard deviation ) untreated areas ranged from 59.6 % ( + /-14.9 , group PT/2 ) to 79.9 % ( + /-10.3 , PT/1 ) for the total canal length and 65.2 % to 74.7 % for the apical canal portion , respectively . Canals in group PT/1 had greater untreated surface areas ( p < 0.01 ) than groups PT/2 and PT/CF . Among all groups , amounts of treated surface areas were statistically similar in the apical 4 mm . CONCLUSIONS Preparations of oval-shaped root canals in m and ibular molars left a variable portion of surface area unprepared regardless of the instrumentation technique used . However , considering oval canals as two separate entities during preparation appeared to be beneficial in increasing overall prepared surface 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 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 INTRODUCTION The purpose of this study was to evaluate the canal isthmus debridement efficacy of a new modified EndoVac ( Discus Dental , Culver City , CA ) irrigation protocol in comparison with EndoVac , passive 
    Output:
    