Risk is part of all health professions and generally indicates the chance of getting some form of illness. For dental practitioners this includes periodontitis or peri‐implantitis, the focus of this issue. Many risk factors are involved in the development of disease and most likely interact or overlap. Most patients will probably have multiple risk factors, some of which will be the same for both periodontitis and peri‐implantitis. The most recent classification of periodontal disease recognises the importance of risk factors and contemporary dental practice requires that clinicians be aware of and manage them. Broadly speaking risk factors can be patient, environment or practitioner related. Patient risk factors would include socio‐economic status, smoking, substance use disorders, diabetes, diet and dietary supplements, mental health disorders, old age, poor home dental care or understanding of the need for good home care and use of medications. Environmental modification of the host response through gene function is an emerging risk factor. Lastly, practitioner‐related factors in implant dentistry are now known to affect risk. These would include the use of digital technology, but patient related factors such implant location and the body’s reaction to an implant itself add to the risk of developing disease. This edition of Periodontology provides an uptodate review of many of these risk factors and their impact summarising current knowledge.

Mental health disorders, particularly depression and anxiety, affect a significant number of the global population. Several pathophysiological pathways for these disorders have been identified, including the hypothalamic‐pituitary‐adrenal axis, autonomic nervous system, and the immune system. In addition, life events, environmental factors, and lifestyle affect the onset, progression, and recurrence of mental health disorders. These may all overlap with periodontal and/or peri‐implant disease. Mental health disorders are associated with more severe periodontal disease and, in some cases, poorer healing outcomes to nonsurgical periodontal therapy. They can result in behavior modification, such as poor oral hygiene practices, tobacco smoking, and alcohol abuse, which are also risk factors for periodontal disease and, therefore, may have a contributory effect. Stress has immunomodulatory effects regulating immune cell numbers and function, as well as proinflammatory cytokine production. Stress markers such as cortisol and catecholamines may modulate periodontal bacterial growth and the expression of virulence factors. Stress and some mental health disorders are accompanied by a low‐grade chronic inflammation that may be involved in their relationship with periodontal disease and vice versa. Although the gut microbiome interacting with the central nervous system (gut‐brain axis) is thought to play a significant role in mental illness, less is understood about the role of the oral microbiome. The evidence for mental health disorders on implant outcomes is lacking, but may mainly be through behaviourial changes. Through lack of compliance withoral hygiene and maintenance visits, peri‐implant health can be affected. Increased smoking and risk of periodontal disease may also affect implant outcomes. Selective serotonin reuptake inhibitors have been linked with higher implant failure. They have an anabolic effect on bone, reducing turnover, which could account for the increased loss.

Background: There is a large body of evidence using cells and animal models demonstrating the effectiveness of growth factors in periodontal regeneration. However, there appears to be minimal literature comparing the efficacy of growth factors in human periodontal regeneration compared to other techniques and procedures. Therefore, the aim of this study is to perform a systematic review of human studies using growth factors for periodontal regeneration and to compare the efficacy of these growth factors to other accepted techniques for periodontal regeneration.Methods: An electronic and manual search based on agreed search phrases between the primary investigator and a secondary investigator was performed to identify the use of growth factors in periodontics for the literature review. The articles that were identified by this systematic review were analyzed in detail, which included the study of their inclusion and exclusion criteria, outcome measures determination and analysis, risk of bias, adverse events, and conclusions or inference of the efficacy of growth factors to the general population.Results: Five papers fulfilled the inclusion criteria. Two papers were identified that had sufficiently similar study design that a meta‐analysis of their outcomes was possible. Most of the reported outcomes from the selected papers were descriptive. The articles demonstrated periodontal regeneration at least comparable to their respective positive controls, with only a couple of articles demonstrating significantly greater outcomes compared to their respective positive controls. 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.Conclusions: 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.