***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 aim of this clinical study was to evaluate the association of locally delivered doxycycline ( 10 % ) with scaling and root planing in the periodontal treatment of smokers . METHODS Forty-three patients with chronic periodontitis and a minimum of four pockets ( > or = 5 mm ) on anterior teeth that bled on probing were selected . Patients were r and omly assigned to scaling and root planing ( SRP ) or scaling and root planing followed by local application of doxycycline ( SRP-D ) .  Plaque , bleeding on probing , gingival recession , relative attachment level ( RAL ) , and probing depth ( PD ) were recorded at baseline , 45 days , and 3 and 6 months . Differences between baseline and each period were considered for analysis . RESULTS At 6 months , no difference was found between groups regarding plaque , bleeding reduction , gingival recession or PD ( P > 0.05 ) . However , RAL gain was greater for SRP-D ( 1.63 + /- 0.93 mm ) than for SRP ( 1.04 + /- 0.71 mm ) ( P = 0.025 ) . In addition , deep pockets ( > or = 7 mm ) showed a significant reduction ( 3.78 + /- 1.41 versus 2.60 + /- 1.28 mm , P = 0.039 ) and RAL gain ( 2.54 + /- 1.27 mm versus 1.29 + /- 0.95 mm , P = 0.01 ) when doxycycline was applied . The proportion of sites showing RAL gain of 1 to 2 mm was 36.8 % versus 21.7 % for SRP-D and SRP , respectively ( P = 0.01 ) . CONCLUSION The use of locally delivered doxycycline may constitute an important adjunct for the treatment of severe periodontal disease in smokers BACKGROUND Although scaling and root planing are considered the therapeutic st and ard for periodontitis , weakly responding sites often occur . To improve treatment outcome , several chemomechanical treatment concepts have been developed . Recently , the clinical surplus value of a highly concentrated chlorhexidine varnish has been shown when used as an adjunct to sequential scaling and root planing . The aim of this study was to explore the clinical effects of a treatment strategy for chronic periodontitis based on a combination of same-day full-mouth root planing and subgingival chlorhexidine varnish administration . METHODS A r and omized , controlled , single-blind , parallel trial was conducted on 12 chronic periodontitis patients . The control group received oral hygiene instructions and same-day full-mouth root planing . The test group received the same instructions and treatment ; however , all pockets were additionally disinfected using a chlorhexidine varnish .  Clinical response parameters were recorded at baseline and subsequently after 1 and 3 months . RESULTS Both treatment strategies showed significant reductions in probing depth at both follow-up visits in comparison with baseline levels ( P < or=0.029 ) . Yet , at 3 months , initially diseased sites of the test group showed significant additional pocket reductions between 0.70 and 1.37 mm ( P < or=0.021 ) . Furthermore , a significant additive clinical attachment gain of 1.17 mm ( P = 0.049 ) for initially deep pockets ( > or=7 mm ) was found favoring the test group . CONCLUSION These preliminary findings suggest that the outcome of same-day full-mouth root planing may benefit from the subgingival administration of a highly concentrated chlorhexidine varnish The present study was performed to assess and compare the clinical healing and the microbiological findings following local application of metronidazole or tetracycline to augment subgingival scaling in previously untreated adult periodontitis sites . Eighteen patients with moderate to severe adult periodontitis at single-rooted teeth were selected . In each patient , 3 interproximal sites having comparable root anatomy , probing depth > or = 5 mm and bleeding on probing were r and omly assigned to 1 of 3 treatment groups : 1 ) two sessions of subgingival scaling and root planing ; 2 ) similar to 1 , with each treatment supplemented with a 25 % metronidazole sustained release gel ; 3 ) similar to 1 with each treatment supplemented with a 3 % tetracycline ointment . The treatments were performed by 1 operator and the clinical variables probing depth , attachment level , and bleeding on probing were evaluated at baseline , 3 months and 6 months by a second blinded examiner . The microbiological findings were evaluated using a commercial test kit . The average probing depth reduction for the 3 groups at 6 months was 1.5 mm and the average gain of clinical attachment was 0.8 mm . There were no significant differences between the effects following topical application of the metronidazole gel or the tetracycline ointment . Scaling and root planing alone appeared as effective as the drug augmented regimens , although there was a weak but non-significant tendency for better results in sites treated with the antibiotic drugs . Actinobacillus actinomycetemcomitans was generally not detected ; Prevotella intermedia was not significantly reduced , while Porphyromonas gingivalis was significantly reduced in all treatment groups . It was concluded that the augmentative effect of the metronidazole gel and the tetracycline ointment was comparable but small compared to scaling and root planing alone . The clinical importance of such small augmentation effects should be further evaluated BACKGROUND Currently , several local antimicrobial delivery systems are available to periodontists . The aim of this 6-month follow-up parallel study was to evaluate the efficacy of three commercially available local delivery systems as adjuncts to scaling and root planing in the treatment of sites with persistent periodontal lesions . METHODS Seventy-nine patients with 4 pockets > or = 5 mm and bleeding on probing and /or suppuration were r and omized into 4 treatment groups which included : scaling and root planing alone ( S ) ( 20 patients ) , or in conjunction with the application of 25 % tetracycline fibers ( S+Tet ) ( 19 patients ) , or 2 % minocycline gel ( S+Min ) ( 21 patients ) , or 25 % metronidazole gel ( S+Met ) ( 19 patients ) . Clinical measurements were taken at baseline , 6 weeks , 3 months , and 6 months after antimicrobial application . Treatments were applied using the distributors ' recommended protocol s. RESULTS All 4 therapies result ed in significant improvements from baseline in probing depth , attachment level , bleeding on probing , and the Modified Gingival Index ( MGI ) scores . The improvements in clinical parameters were greater in all 3 adjunctive treatment groups than scaling and root planing alone . The mean probing depth reductions at 6 months were : scaling + tetracycline = 1.38 mm ; scaling + metronidazole = 0.93 mm ; scaling + minocycline = 1.10 mm ; and scaling alone = 0.71 mm . The probing depth reduction at all time points was significantly greater in the scaling plus tetracycline fiber group than the scaling and root planing alone group ( P<0.01 ) . There was also a significant improvement for scaling plus tetracycline fiber application over scaling and metronidazole at both 6 weeks and 3 months , although this did not remain significant at the 6-month visit . While the frequency of sites with suppuration was markedly reduced following all antimicrobial treatments , the most effective reductions were seen in the scaling plus tetracycline fiber group , followed by the minocycline group . CONCLUSIONS Although all 3 locally applied antimicrobial systems seem to offer some benefit over scaling and root planing alone , a treatment regimen of scaling and root planing plus tetracycline fiber placement gave the greatest reduction in probing depth over the 6 months after treatment BACKGROUND Several antibacterial agents have been studied as a means to produce bactericidal or bacteriostatic activity as an adjunct to mechanical treatment of periodontal disease . The primary purpose of this study was to evaluate the efficacy of tetracycline strips administered singly or in multiples in conjunction with root planing , versus root planing alone , or to an untreated control . Secondary purpose s were to compare gingival crevicular fluid ( GCF ) volume and GCF concentrations of tetracycline in pockets treated with strips ; to evaluate strip insertion time ; and to compare ease of placement for single or multiple strips . METHODS Using a 4-quadrant design , 4 test teeth in 24 patients were treated with either root planing and single strip application ; root planing and multiple strip application ; root planing alone ; or an untreated control . RESULTS Single and multiple strip placement result ed in a significant reduction in probing depth ( P = 0.033 ) compared to root planing and untreated groups . The multiple strip group significantly decreased bleeding on probing ( P = 0.05 ) compared to all other treatment groups . There was no treatment effect on GCF ; however , there was a significant reduction in the GCF volume over time ( P = 0.001 ) . The time required for placement was , on average , 1.9 minutes for single strips and 3.25 minutes for multiple strips . CONCLUSIONS Our data suggest that multiple strips are superior to a single strip in reducing bleeding on probing , and that local delivery of tetracycline is superior to root planing alone in reducing probing depth AIM To determine whether adjunctive metronidazole therapy would compensate for the poorer treatment response to scaling and root planing reported in smokers . METHOD A single-blind , r and omised clinical trial of 28 smokers and 56 non-smokers , stratified for periodontitis disease severity and r and omly allocated to 3 treatment groups : ( 1 ) Scaling and root planing using an ultrasonic scaler with local anaesthesia ( SRP ) , ( 2 ) SRP+ metronidazole tabs 200 mg tds for 7 days , ( 3 ) SRP + 2 subgingival applications of 25 % metronidazole gel .  Probing depths ( PD ) and attachment levels ( AL ) were recorded with a Florida probe at baseline , 2 months and 6 months post treatment by a single examiner who was unaware of the treatment modality . Results were analysed for all sites with baseline probing depths equal to or greater than Florida probe recordings of 4.6 mm using analysis of variance . RESULTS Reductions in probing depth at 6 months were significantly less ( p < 0.001 ) in the smokers ( mean 1.23 mm , 95 % confidence intervals = 1.05 to 1.40 mm ) than in the non-smokers ( 1.92 , 1.75 to 2.09 mm ) . Attachment level gains were approximately 0.55 mm and there was no statistically significant difference between smokers and non-smokers . There were no differences in any clinical measure in response to the three treatment regimens at 2 or 6 months for either smokers or non-smokers . A reduction in the proportion of spirochaetes was observed at 6 months which was less in smokers than in non-smokers ( p = 0.034 ) . Multiple linear regression analysis on probing depth at 6 months demonstrated that smoking was a significant explanatory factor ( p < 0.001 ) for poor treatment outcome , whilst the presence or absence of adjunctive metronidazole was not ( p = 0.620 ) . CONCLUSION This study confirms that smokers have a poorer treatment response to SRP , regardless of the application of either systemic or locally applied adjunctive metronidazole BACKGROUND Tetracyclines have been extensively used as adjunctives to conventional periodontal therapy . Emergence of resistant strains , however , has been reported . This study evaluated longitudinally the tetracycline resistance patterns of the subgingival microbiota of periodontitis subjects treated with systemic or local tetracycline therapy+scaling and root planing ( SRP ) . METHODS Thirty chronic periodontitis patients were r and omly assigned to three groups : SRP+500 mg of systemic tetracycline twice/day for 14 days ; SRP alone and SRP+tetracycline fibers ( Actsite ) at four selected sites for 10 days . Subgingival plaque sample s were obtained from four sites with probing pocket depths ( PPD ) > or = 6 mm in each patient at baseline , 1 week , 3 , 6 and 12 months post-therapy . Sample s were dispersed and diluted in pre-reduced anaerobically sterilized Ringer 's solution , plated on Trypticase Soy Agar (TSA)+5 % blood with or without 4 microg/ml of tetracycline and incubated anaerobically for 10 days . The percentage of resistant microorganisms were determined and the isolates identified by DNA probes and the checkerboard method . Significance of differences among and within groups over time was sought using the Kruskal-Wallis and Friedman tests , respectively . RESULTS The percentage of resistant microorganisms increased significantly at 1 week in the tetracycline groups , but dropped to baseline levels over time . The SRP+Actsite group presented the lowest proportions of resistant species at 6 and 12 months . No significant changes were observed in the SRP group . The predominant tetracycline-resistant species included Streptococcus spp . , Veillonela parvula , Peptostreptococcus micros , Prevotella intermedia , Gemella morbillorum and Actinobacillus actinomycetemcomitans ( Aa ) . A high percentage of sites with resistant Aa , Porphyromonas gingivalis and Tanerella forsythensis was observed in all groups at baseline . However , T. forsythensis was not detected in any group and P. gingival 
    Output:
    
The local application of chlorhexidine and metronidazole showed a minimal effect when compared with placebo ( WMD between 0.1 and 0.4 mm ) .
The scientific evidence supports the adjunctive use of local antimicrobials to debridement in deep or recurrent periodontal sites , mostly when using vehicles with proven sustained release of the antimicrobial