complete pooling of data for a more comprehensive analyses. it was difficult to establish definitive conclusions, although patients with deep pockets, progressive or 'active' disease, or specific microbiological profile, can benefit more from this adjunctive therapy." there is currently low-quality evidence suggesting if adjunctive systemic antimicrobials are beneficial for the non-surgical treatment of periodontitis. it is not sure whether some antibiotics are better than others when used alongside scaling and root planning). locally delivered adjunctive antimicrobial treatment chemical antimicrobials may be used by the clinician to help reduce the bacterial load in the diseased pocket. "among the locally administered adjunctive antimicrobials, the most positive results occurred for tetracycline, minocycline, metronidazole, and chlorhexidine. adjunctive local therapy generally reduced pd levels....whether such improvements, even if statistically significant, are clinically meaningful remains a question." minocycline is typically delivered via slim syringe applicators. chlorhexidine impregnated chips are also available. hydrogen peroxide is a naturally occurring antimicrobial that can be delivered directly to the gingival sulcus or periodontal pocket using a custom formed medical device called a perio tray. [title = custom tray application of peroxide gel as an adjunct to scaling and root planing in the treatment of periodontitis: a randomized, controlled three-month clinical trial j clin dent 2012;23:48–56.] hydrogen peroxide gel was demonstrated to be effective in controlling the bacteria biofilm the research shows that a direct application of hydrogen peroxide gel killed virtually all of the bacterial biofilm, was directly and mathematically delivered up to 9mm into periodontal pockets. modulating the host response sub-antimicrobial doses of doxycycline (sdd) have been used to alter host response to the periodontal pathogens. this is believed to disrupt the action of matrix metalloproteinases and thus minimise host mediated tissue destruction. "the adjunctive use of sdd with srp is statistically more effective than srp alone in reducing pd and in achieving cal gain." systemic factors chronic periodontitis is an inflammatory immune response against the presence of bacteria present. recent research has suggested that epithelial lining ulceration in chronic periodontal pockets are due to systemic bacterial dissemination and widespread bacterial inflammatory markers present in the host. two of the most widely investigated systemic diseases associated with chronic periodontitis is diabetes mellitus and cardiovascular disease. diabetes mellitus both type 1 and type 2 diabetes have shown a link with the treatment and progression of chronic periodontitis. chronic periodontitis is more serve in patients that have diabetes than those without, confirming a significant association. with type 2 diabetes patients being shown to have 3.8 times more bone loss and 2.8 times more clinical attachment loss than non-diabetic individuals. with patients with poorly controlled diabetes having a higher risk of alveolar bone loss. chronic periodontitis can also be a metabolic stressor influencing diabetes control, influencing insulin resistance or becoming a source of inflammatory marker secretion which may strengthen the amount of advanced glycation end product (age) mediated cytokine response. monocytic hyperresponsiveness to bacterial antigen is a biological mechanism that links periodontal disease and diabetes. increased production of proinflammatory cytokines and mediators cause tissue destruction, attachment loss as well as bone loss causing delayed wound healing. cardiovascular disease chronic periodontitis is a marker for cardiovascular disease (cvd). mechanisms associated with cardiovascular risk are that chronic periodontitis increases inflammatory mediator levels and this may contribute to the onset of cvd, while treatment of chronic periodontitis reduces systemic levels of inflammatory mediators. certain bacteria found in the periodontal pockets have also been associated to cause atheromatous plaques. treatment protocol for chronic periodontitis with cvd does not need to be modified as normal periodontal treatment techniques are seen to be effective in cvd patients with additional supportive therapy. costs of treatment "costs for tooth retention via supportive periodontal therapy are relatively low compared with alternatives (e.g. implants or bridgework) even in periodontally impaired teeth.". however, health outcomes of periodontal therapy are not directly comparable with those from implants or bridgework. research management for adults without severe periodontitis and who get routine dental care, regular scale and polish treatment does not make any difference to gingivitis, probing depths or other oral health-related problems. it seems that there is also no difference in plaque levels. lasers are increasingly being used in treatments for chronic periodontitis. however, there is some controversy over their use: "no consistent evidence supports the efficacy of laser treatment as an adjunct to non-surgical periodontal treatment in adults with chronic periodontitis." tentative links to other conditions there is little evidence linking progression of periodontal disease to low birth weight or preterm birth: "in these women with periodontitis and within this study's limitations, disease progression was not associated with an increased risk for delivering a pre-term or a low birthweight infant." there is recently emerged evidence linking chronic periodontitis with head and neck squamous cell carcinoma: "patients with periodontitis were more likely to have poorly differentiated oral cavity scc than those without periodontitis (32.8% versus 11.5%; p = 0.038)".