***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: BACKGROUND The primary aims of this two-part prospect i ve study were : 1 ) to compare the safety and efficacy of beta-tricalcium phosphate ( beta-TCP ) + 0.3 mg/ml recombinant human platelet-derived growth factor-BB ( rhPDGF-BB ) with a bioabsorbable collagen wound-healing dressing and a coronally advanced flap ( CAF ) to a subepithelial connective tissue graft ( CTG ) in combination with a CAF in subjects with gingival recession defects using a r and omized , controlled , split-mouth design ; and 2 ) to compare , through histologic and microcomputed tomography ( micro-CT ) examination , the periodontal regenerative potential of these two therapies in surgically created gingival recession defects in restoring missing cementum , periodontal ligament ( PDL ) , and supporting alveolar bone . METHODS In the r and omized controlled trial ( RCT ) , 30 patients with Miller Class II buccal gingival recession , > or = 3 mm deep and > or = 3 mm wide in contralateral quadrants of the same jaw were treated and followed for 6 months . Using a split-mouth design with similar bilateral recession defects , test sites were treated with 0.3 mg/ml rhPDGF-BB + beta-TCP + bioabsorbable collagen wound-healing dressing ; contralateral control sites were treated with a CTG , each in combination with a CAF . In the histologic/micro-CT study segment , recession defects were created in six teeth , each requiring extraction for orthodontic therapy . These defects were created with a recession depth > or = 3 mm , the osseous crest 2 to 3 mm apical to the gingival margin , and with 2 to 3 mm of keratinized tissue . The defects were treated with a CTG ( control ) or rhPDGF-BB + beta-TCP + wound-healing dressing ( test ) , plus CAF . Nine months after surgical correction , en bloc resections were obtained and examined histologically and with micro-CT . RESULTS In the RCT , test and control treatments demonstrated clinical ly significant improvements from baseline through month 6 . Statistically significant results favoring the CTG were found in recession depth reduction ( -2.9 + 0.5 mm , test ; -3.3 + 0.6 mm , control ; P = 0.009 ) , root coverage ( 90.8 % , test ; 98.6 % , control ; P = 0.013 ) , and -3.9 + /- 0.7 mm , control , -3.3 + /- 1.3 mm , test , recession width reduction ( P = 0.035 ) , whereas mid-buccal probing depth ( PD ) and PD reduction ( PDR ) reduction favored the test group ( 1.4 + /- 0.4 mm , test ; 1.8 + /- 0.1 mm , control ; P < 0.001 PD and -0.0 mm test ; + 0.4 mm control PDR ) . For all other parameters , the two treatments were statistically equivalent , including increases in keratinized tissue , esthetic results , and subject satisfaction . In the histologic/micro-CT portion , all four sites treated with rhPDGF-BB + beta-TCP showed evidence of regeneration of cementum , PDL with inserting connective tissue fibers , and supporting alveolar bone , whereas neither CTG-treated site exhibited any signs of periodontal regeneration . CONCLUSIONS CTG and rhPDGF-BB + beta-TCP + wound-healing dressing are effective treatment modalities for clinical ly correcting gingival recession defects . In addition , the current study demonstrated that regeneration of the periodontium in gingival recession defects was possible through a growth factor-mediated approach BACKGROUND Purified recombinant human platelet-derived growth factor BB ( rhPDGF-BB ) is a potent wound healing growth factor and stimulator of the proliferation and recruitment of both periodontal ligament ( PDL ) and bone cells . The hypothesis tested in this study was that application of rhPDGF-BB incorporated in bone allograft would induce regeneration of a complete new attachment apparatus , including bone , periodontal ligament , and cementum in human interproximal intrabony defects and molar Class II furcation lesions . METHODS Nine adult patients ( 15 sites ) with advanced periodontitis exhibiting at least one tooth requiring extraction due to an extensive interproximal intrabony and /or molar Class II furcation defect were entered into the study . Eleven defects were r and omly selected to receive rhPDGF-BB . Following full-thickness flap reflection and initial debridement , the tooth roots were notched at the apical extent of the calculus , the osseous defects were thoroughly debrided , and the tooth root(s ) were planed/prepared . The osseous defects were then filled with demineralized freeze-dried bone allograft ( DFDBA ) saturated with one of three concentrations of rhPDGF-BB ( 0.5 mg/ml , 1.0 mg/ml , or 5.0 mg/ml ) . Concurrently , four interproximal defects were treated with a well accepted commercially available graft ( anorganic bovine bone in collagen , ABB-C ) and a bilayer collagen membrane .  Radiographs , clinical probing depths , and attachment levels were obtained preoperatively ( at baseline ) and 9 months later . At 9 months postoperatively , the study tooth and surrounding tissues were removed en bloc . Clinical and radiographic data were analyzed for change from baseline by defect type and PDGF concentration . The histologic specimens were analyzed for the presence of regeneration of a complete new attachment apparatus coronal to the reference notch . RESULTS The post-surgical wound rapidly healed and was characterized by firm , pink gingivae within 7 to 10 days of surgery . There were no unfavorable tissue reactions or other safety concerns associated with the treatments throughout the course of the study . In rhPDGF/allograft sites , the vertical probing depth ( vPD ) reduction for interproximal defects was 6.42 + /- 1.69 mm ( mean + /- SD ) and clinical attachment level ( CAL ) gain was 6.17 + /- 1.94 mm ( both P < 0.01 ) . Radiographic fill was 2.14 + /- 0.85 mm . Sites filled with ABB-C had a PD reduction and CAL gain of 5.75 + /- 0.5 and 5.25 + /- 1.71 , respectively . Furcation defects treated with rhPDGF/allograft exhibited a mean horizontal and vertical PD reduction of 3.40 + /- 0.55 mm ( P < 0.001 ) and 4.00 + /- 1.58 mm ( P < 0.005 ) , respectively . The CAL gain for furcation defects was 3.2 + /- 2.17 mm ( P < 0.030 ) . Histologic evaluation revealed regeneration of a complete periodontal attachment apparatus , including new cementum , PDL , and bone coronal to the root notch in four of the six interproximal defects and all evaluable ( four of four ) furcation defects treated with PDGF . Two of the four interproximal intrabony defects treated with ABB-C and membrane exhibited regeneration . CONCLUSIONS Use of purified rhPDGF-BB mixed with bone allograft results in robust periodontal regeneration in both Class II furcations and interproximal intrabony defects . This is the first report of periodontal regeneration demonstrated histologically in human Class II furcation defects AIM the objective of the study was to evaluate the safety and efficacy of a formulation containing recombinant human platelet-derived growth factor ( rhPDGF-BB ) and β-tricalcium phosphate ( β-TCP ) in patients with periodontal defects and to compare it with those of β-TCP alone . MATERIAL S AND METHODS in this double-blind , prospect i ve , parallel , active-controlled , r and omized , multi-centre clinical trial , 54 patients with periodontal osseous defects were r and omly assigned to rhPDGF-BB+β-TCP or β-TCP . Following periodontal surgery , respective implantation was performed . The primary and secondary end points of treatment were evaluated at the third and the sixth month . RESULTS among the outcome measures , the extent of linear bone growth ( p<0.01 ) and per cent bone fill ( p<0.004 ) at the sixth month over baseline were significantly higher in the rhPDGF-BB+β-TCP group when compared with the β-TCP group . Similarly , it also result ed in significantly higher area under the curve clinical attachment level gain at 0 - 6 months ( p<0.01 ) , CAL gain and greater reduction in probing depth at the third and the sixth month than that with β-TCP treatment alone . The incidence of adverse events was similar in both the groups and no serious adverse events were reported in any of the patients . CONCLUSIONS rhPDGF-BB+β-TCP is safe and effective in the treatment of periodontal defects . It increases bone formation and soft tissue healing ( clinical trials.gov , number NCT00496847 ; CTRI No. : CTRI/2008/091/000152 ) BACKGROUND Growth factors are generally accepted to be essential mediators of tissue repair via well-established mechanisms of action that include stimulatory effects on angiogenesis and cellular proliferation , ingrowth , differentiation , and matrix bio synthesis . The aim of this study was to evaluate in a large-scale , prospect i ve , blinded , and r and omized controlled clinical trial the safety and effectiveness of purified recombinant human platelet-derived growth factor ( rhPDGF-BB ) mixed with a synthetic beta-tricalcium phosphate ( beta-TCP ) matrix for the treatment of advanced periodontal osseous defects at 6 months of healing . METHODS Eleven clinical centers enrolled 180 subjects , each requiring surgical treatment of a 4 mm or greater intrabony periodontal defect and meeting all inclusion and exclusion criteria . Subjects were r and omized into one of three treatment groups : 1 ) beta-TCP + 0.3 mg/ml rhPDGF-BB in buffer ; 2 ) beta-TCP + 1.0 mg/ml rhPDGF-BB in buffer ; and 3 ) beta-TCP + buffer ( active control ) . Safety data were assessed by the frequency and severity of adverse events . Effectiveness measurements included clinical attachment levels ( CAL ) and gingival recession ( GR ) measured clinical ly and linear bone growth ( LBG ) and percent bone fill ( % BF ) as assessed radiographically by an independent central ized radiology review center . The area under the curve ( AUC ) , an assessment of the rate of healing , was also calculated for CAL measurements . The surgeons , clinical and radiographic evaluators , patients , and study sponsor were all masked with respect to treatment groups . RESULTS CAL gain was significantly greater at 3 months for group 1 ( rhPDGF 0.3 mg/ml ) compared to group 3 ( beta-TCP + buffer ) ( 3.8 versus 3.3 mm ; P = 0.032 ) , although by 6 months , this finding was not statistically significant ( P = 0.11 ) . This early acceleration of CAL gain led to group 1 exhibiting a significantly greater rate of CAL gain between baseline and 6 months than group 3 as assessed by the AUC ( 68.4- versus 60.1-mm weeks ; P = 0.033 ) . rhPDGF ( 0.3 mg/ml)-treated sites also had significantly greater linear bone gain ( 2.6 versus 0.9 mm , respectively ; P < 0.001 ) and percent defect fill ( 57 % versus 18 % , respectively ; P < 0.001 ) than the sites receiving the bone substitute with buffer at 6 months . There was less GR at 3 months in group 1 compared to group 3 ( P = 0.04 ) ; at 6 months , GR for group 1 remained unchanged , whereas there was a slight gain in gingival height for group 3 result ing in comparable GR . There were no serious adverse events attributable to any of the treatments . CONCLUSIONS To our knowledge , this study is the largest prospect i ve , r and omized , triple-blinded , and controlled pivotal clinical trial reported to date assessing a putative periodontal regenerative and wound healing therapy . The study demonstrated that the use of rhPDGF-BB was safe and effective in the treatment of periodontal osseous defects . Treatment with rhPDGF-BB stimulated a significant increase in the rate of CAL gain , reduced gingival recession at 3 months post-surgery , and improved bone fill as compared to a beta-TCP bone substitute at 6 months This prospect i ve multicenter intra-individual r and omized controlled clinical trial was design ed to compare the efficacy of guided tissue regeneration ( GTR ) with bioresorbable barrier membranes versus access flap surgery , in intrabony defects . 2 similar defects were selected in each of 23 patients and r and omly assigned to 1 of the 2 treatments . Surgery consisted of an identical procedure except for the omission of the barrier membrane in the flap control sites . At 1-year , probing pocket depth reductions were 4.3+/-2.3 mm in GTR treated sites and 3.0+/-1.5 mm in the flap control sites ( p=0.02 , paired t-test ) . Clinical attachment level ( CAL ) gains were 3.0 
    Output:
    
Histologic evidence demonstrated greater periodontal regeneration when using growth factors compared to other regenerative techniques and an increased healing and bone maturation rate compared to other regenerative and bone augmentation techniques in these human studies .
Within the limits of this systematic review , the use of recombinant human platelet-derived growth factor-BB ( rhPDGF-BB ) led to greater clinical attachment level gain of ≈1 mm compared to an osteoconductive control , β-tricalcium phosphate ( β-TCP ) .
The use of rhPDGF-BB led to greater percentage bone fill of ≈40 % compared to the osseoconductive control , β-TCP .
Last , the use of rhPDGF-BB led to an increased rate of bone growth of ≈2 mm compared to the osseoconductive control , β-TCP