***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: The present study was design ed to quantitatively assess radiographic changes in alveolar bone density in intrabony defects treated with  exp and ed polytetrafluorethylene membranes ( ePTFE ) or by conventional flap surgery alone .  15 patients with 2 periodontal defects of comparable morphology which could be depicted on a single radiograph made up the test panel . St and ardized radiographs of the periodontal defects were taken immediately prior to surgery and 12 months later . The 2 defects were treated simultaneously using the modified Widman flap procedure and prepared for membrane placement . Then one of the lesions was r and omly assigned for treatment with the membrane . All radiographs and surgical procedures were managed by one person . The radiographs were assessed by another person according to a blind design . Periodontal defects treated with ePTFE membranes ( test ) , and sites treated by conventional flap procedures ( control ) were then analyzed using a computerized image analysis program . In 8 patients , the test site outcome was better than the outcome in the control site . 6 of the control sites indicated increased bone density , while 7 sites showed decreased values , and 2 sites were unchanged . The corresponding values from the test sites were 5 , 6 and 4 , respectively . In the present controlled clinical study , the use of an ePTFE membrane to cover the opening of a vertical bone defects during periodontal surgery did not predictably increase the bone density of the defects The purpose of this study was to evaluate the clinical effectiveness of a connective tissue graft including periosteum used as a barrier for guided periodontal tissue regeneration in interproximal bony defects . An open flap debridement of a comparable interproximal bony defect in the same patient was used as a control . This study was performed at 2 different clinical centers . Six paired defects were treated at one center , and 16 paired defects at the other .  Reentry surgeries were performed at 6 months . Preoperative comparisons of control and experimental sites with respect to clinical parameters and osseous measurements were similar . Post-surgical experimental sites produced more gain in clinical attachment ( 1.25 mm on buccal and 1.25 mm on lingual sites at center A and 1.26 mm on buccal and 1.18 mm on lingual sites at center B ) and osseous defect fill ( 1.84 mm on buccal and 2.00 mm on lingual sites at center A and 1.66 mm on buccal and 2.04 mm on lingual sites at center B ) when compared to control sites . The results of this trial indicate that clinical resolution of interproximal periodontal defects can be obtained with periosteal grafts used as barriers This clinical and radiological study evaluated the healing of 3 + 2 + 1 wall-combined intrabony defects treated using the guided tissue regeneration technique ( GTR ) with and without hydroxyapatite-collagen alloplastic graft material s ( HAC ) , in comparison to that of HAC alone and conventional flap surgery ( CF ) .  40 interproximal defects with probing depth > 6 mm were treated in 18 adult periodontitis patients of ages 35 - 60 years . After non-surgical therapy , the defects were r and omly grouped into 4 groups of 10 defects each . These groups were design ated : ( 1 ) exp and ed polytetrafluoroethylene membrane ( e-PTFE ) , ( 2 ) e-PTFE + HAC , ( 3 ) HAC alone and ( 4 ) CF . At 6 months , the following changes in parameters were recorded . Mean PPD reduction for each group was 5.83 , 5.85 , 3.80 and 3.17 mm respectively . PPD reduced very significantly in all groups ( p < 0.01 ) , the highest and lowest reductions in PPD being for the e-PTFE + HAC and CF group respectively . Comparison between the 4 groups showed higher PPD reduction in both membrane groups than in either of the non membrane groups ( p < 0.05 ) with the difference between the e-PTFE and CF groups being very highly significant ( p < 0.001 ) . Mean attachment gain for the 4 groups was 3.70 , 3.80 , 2.60 and 2.1 mm , respectively . Similarly attachment gain for all groups was very significant ( p < 0.01 ) and the highest and lowest attachment gains were for the e-PTFE + HAC and CF group respectively . Both membrane groups showed significantly more attachment gain than the CF group ( p < 0.05 ) . Change in probing bone level ( BL ) for the 4 groups was 1.60 , 1.90 , 1.0 and 0.65 mm respectively . Again the highest changes in BL were recorded for the e-PTFE + HAC group . Significant differences were found between both membrane groups and the CF group ( p < 0.05 ) . Radiological evaluation using st and ardized radiographs and millimeter grids showed change in radiographic bone level at the deepest point of the defect on the radiograph to be 1.50 , 1.55 , 0.85 and 0.60 mm , respectively and this was significantly higher in both membrane groups than in the CF group ( p < 0.05 ) . This study therefore found e-PTFE membranes both alone and when combined with HAC to lead to more attachment gain and bone fill than did HAC alone or CF . It found HAC combined with e-PTFE to perform better although not significantly better than e-PTFE alone The aim of this controlled , clinical study was to evaluate guided tissue regeneration using a bioabsorbable membrane in periodontal intraosseous defects . Forty patients , each contributing one defect > or = 4 mm in depth participated . The control group ( 18 individuals ) received conventional flap therapy , while the test group ( 22 individuals ) was treated using the bioabsorbable membrane , Guidor . Clinical assessment s were made by one examiner , blinded with respect to treatment group , at baseline , 6 and 12 months following surgery . Baseline probing pocket depths of 7.7+/-1.4 mm in the membrane group and 7.6+/-1.9 mm in the control group were measured . Twelve month results showed a significant clinical attachment level gain in both control ( 1.1+/-1.8 mm ) , and membrane group ( 1.3+/-2.1 mm ) . Probing pocket depth reduction of 2.6+/-1.9 mm and 2.7+/-1.9 mm was observed in the respective groups . Bone sounding showed a non-significant gain of 0.4+/-1.8 mm and 0.6+/-1.4 mm at membrane and control sites , respectively . Radiographic evaluation confirmed these results . There were no significant differences found between treatment groups for any of the tested variables . Smoking had a negative effect on healing in both groups . In conclusion , clinical and radiographic results indicate that guided tissue regeneration using a bioabsorbable membrane at intraosseous defects did not predictably achieve greater clinical attachment level gain nor bone gain when compared to conventional flap therapy The purpose of this controlled clinical trial was to compare the clinical efficacy of 3 treatment modalities in the treatment of deep interproximal intrabony defects . Thirty-six ( 36 ) defects in 36 patients were r and omly assigned to 1 of 3 treatment groups by blocking to prognostic variables . The test was treated with bioresorbable membranes positioned coronal to the interproximal bone crest ; the second group ( membrane control ) was treated with conventional non-resorbable ( ePTFE ) barrier membranes applied coronal to the alveolar crest ; the third group ( flap Control ) was treated with an access flap procedure ( MWF ) . No differences were observed in terms of baseline oral hygiene and defect characteristics among the 3 groups , indicating that the blocking approach was effective . A stringent infection control program was enforced for 1 year . The results indicated that : 1 ) at 1 year all treatment modalities result ed in clinical ly significant improvements in clinical attachment levels ( CAL ) and reductions in probing depths ; 2 ) a statistically significant treatment effect ( P < 0.0001 , ANOVA ) was observed comparing the test ( 4.6 + /- 1.2 mm ) , the membrane control ( 5.2 + /- 1.4 mm ) , and the flap control groups ( 2.3 + /- 0.8 mm ) in terms of CAL gain ; 3 ) differences in terms of CAL gain between the test ( bioresorbable ) and the membrane control ( ePTFE ) groups were not statistically significant ( P = 0.19 , t-test ) ; 4 ) both the test and the membrane control groups gained significantly more CAL at 1 year than the MWF group ( P < 0.0001 , t-test ) . CAL gains > or = 4 mm were observed in 83.3 % of cases in both GTR groups , while CAL gains of this magnitude were not detected in the MWF group . We concluded that clinical ly significant CAL gains can be obtained with GTR procedures using both bioresorbable and non-resorbable membranes . Patients ' morbidity , however , was lower in the group treated with bioresorbable membranes BACKGROUND , AIMS The purpose of the present study was to compare the efficacy of 3 different surgical procedures in the treatment of infrabony defects :  guided tissue regeneration ( GTR ) with non-resorbable membranes , Widman modified flap ( WMF ) and enamel matrix derivative ( EMD ) . METHOD 30 patients with an infrabony component > or = 4 mm were selected . 10 were treated with exp and ed polytetrafluorethylene ( ePTFE ( Gore - Tex W. L. Gore and Associates , Flagstaff , AZ , USA ) ) membranes , 10 with WMF and 10 with enamel matrix derivatives ( Emdogain ( U Biora AB Malm , Sweden ) ) . The efficacy of each treatment modality was investigated through regression analysis . Probing attachment level ( PAL ) gain , probing depth ( PD ) reduction and gingival recession ( REC ) variation were analyzed . RESULTS Both Emdogain ( enamel matrix derivative ) and ePTFE treatment show significant better results as compared to the WMF procedure in which there were no significant changes in PAL gain and PD reduction at baseline and 1 year after surgery . CONCLUSIONS Results from our analysis suggest that there is no statistically significant difference in PAL gain between GTR and EMD . The clinical outcomes of this pilot study may be of little significance , considering the small number of patients , but it has provided an important base for a controlled clinical trial ( with a larger number of patients ) which is currently in progress OBJECTIVES Current literature is ambivalent on the use of barrier membranes for regeneration of intraosseous defects . One of the reasons for unpredictable results may be related to infection before , during and after the surgical procedure . Therefore , the purpose of the present controlled study was to evaluate both the use of membranes ( MEM ) and antibiotics ( AB ) , separately and in combination . METHODS In all , 25 patients with two intraosseous periodontal defects each were r and omized in two groups : AB+ group receiving systemic antibiotics ( n = 13 ) and AB- group without antibiotics ( n = 12 ) . After raising flaps and after debridement , both defects in each patient were covered by a bioresorbable membrane ( MEM+ ) . However , just before suturing the flaps in a coronal position , the membrane over one of the two defects was removed at r and om ( MEM- ) . This protocol result ed in four groups of defects : ( i ) . MEM- AB- ; ( ii ) . MEM+ AB- ; ( iii ) . MEM- AB+ ; ( iv ) . MEM+ AB+ . Patients were monitored clinical ly and microbiologically for 1 year . Data were analyzed in repeated measures ancova 's and adjusted means for clinical variables were obtained from the final statistical model . RESULTS Reduction in probing pocket depth ( PPD ) at 12 months postoperatively varied between 2.54 and 3.06 mm between the four treatment modalities , but overall no main effect of  MEM  or  AB  was found . Gains in probing attachment level ( PAL ) at 12 months postoperatively varied between 0.56 and 1.96 mm for the 4 treatments . In the overall analysis for PAL , no main effect of  MEM or AB  was found . Gains in probing bone level ( PBL ) 12 months postoperatively ranged from 1.39 to 2.09 mm between the treatment groups . Again , overall , no main effects of  MEM or AB  were found for PBL . Explorative statistical analyses indicated that smoking and not MEM or AB is a determining factor for gain in PBL ( P = 0.0009 ) . Nonsmokers were estimated to gain 2.04 mm PBL compared to 0.52 mm in smokers . The prevalence of several periodontal pathogens , at the day of surgery or postoperatively , and specific defect characteristics , were not determining factors for gain in PAL and PBL . CONCLUSIONS Neither the application of barrier membranes nor the use of systemic antibiotics showed an additional effect over control on both soft and hard tissue measurements in the treatment of intraosseous defects . In contrast , smoking was a determining factor severely limiting gain in PBL in surgical procedures aim ed at regeneration of intraosseous defects BACKGROUND Different types of barriers are used in guided tissue regenerative procedures . AIM This prospect i ve study compared resorbable citric acid ester softened polylactic acid membranes ( RM ) and non-resorbable exp and ed polytetrafluoroethylene ( ePTFE ) barriers ( NRM ) in GTR treatment of intrabony defects . METHODS 29 subjects were r and omly assigned to the RM group or NRM group . Each patient received one GTR procedure . An open flap debridement ( FD 
    Output:
    
Regarding hard tissue probing at surgical re-entry , a statistically significant greater gain was found for GTR compared with open flap debridement .