| biofilm “The frequent intake of fermentable sugars in the diet, along with a reduction in the flow of saliva, can lead to dysbiosis,” adds Marsh. These sugars, by initiating the development of dental caries, are metabolised into acid, which generates a low pH level in the biofilm. As Peter- son et al. demonstrated in a 2013 study, this low pH can constrain the growth of many bacteria responsible for the health of tooth enamel, decreasing the diversity of the oral microbiome. Some other common causes of dysbiosis include the use of broad-spectrum antibiotics, smoking, physio- logical changes like pregnancy or puberty, and certain diseases that are associated with periodontitis, such as diabetes. Dental implants and biofilm As the popularity of dental implants continues to rise, their use has become more successful in terms of both aesthetics and function. However, even successful pro- 34 prevention 1 2018 cedures can lead to peri-implant mucositis, an inflamma- tory lesion at the mucosal and bone level, which then can progress to peri-implantitis, an inflammatory lesion of the tissue surrounding the implant. Peri-implantitis can develop for a number of reasons. One of the most common is the presence of periodon- tal disease when the implant is placed. If the patient has deep periodontal pockets filled with harmful bacteria, it can lead to colonisation of biofilm around the implant and possibly implant failure. Dr Lisa Heitz-Mayfield is, among other roles, a uni- versity lecturer and a periodontist in private practice. As implant specialist, she says that infection control prior to and after implant placement is essential for control of biofilm and peri-implantitis. “Having good infection control before placing implants is crucial, as it is the best way to prevent these infections occurring later on,” she says. “A preventive approach re- quires several elements to work effectively: regular mon- itoring and supportive periodontal therapy with profes- sional biofilm control, a healthy and regular at-home oral hygiene routine, and controlling for other risk factors, such as smoking and uncontrolled diabetes.” Orthodontic patients and biofilm Despite the advances in technology that have made orthodontic appliances smaller and more comfortable than ever, intraoral problems often arise from their use. A 2014 study by Ren et al. published in Clinical Oral Investigations estimated that at least 60 per cent of all orthodontic patients develop at least one biofilm-related complication. These complications develop primarily be- cause the presence of orthodontic appliances can im- pede toothbrushing and other oral hygiene activities, ren- dering these techniques less effective in disrupting the formation of dental plaque biofilm. Chemical control An alternative method of controlling dental plaque bio- film in orthodontic patients is chemical control through the use of antimicrobials. Chlorhexidine is considered to be the most effective antiseptic agent available, with nu- merous studies demonstrating its efficacy against dental plaque when present in mouthwash. However, Valen et al. found that prolonged daily use of an antimicrobial might lead to resistance to not just the applied substance but other antimicrobials as well. With this in mind, they recommended that daily anti- microbial use for the control and eradication of bio- film should be limited to situations in which mechanical cleaning and patient behavioural change are inadequate or unachievable.