The effect of orthodontic appliances on the Oral Candida colonisation: a systematic review

Objectives To evaluate the influence of Fixed (FOA) and Removable Orthodontic Appliances (ROA) on oral Candida colonisation. Methods A search for articles published in the English language until September 2021, was carried out using Pubmed, Scopus and Web of Knowledge databases and by applying the search terms "orthodontic" OR "orthodontics" OR "fixed appliance" OR "removable appliance" OR "bracket" OR "removable aligner" AND "Candida" OR "Candidiasis" OR "Candidosis" to identify all potentially relevant human studies. After the removal of duplicate articles and data extraction according to the PICOS scheme, the methodological quality of the included papers was assessed by applying the Swedish Council on Technology Assessment in Health Care Criteria for Grading Assessed Studies (SBU). Results The initial search identified 533 articles, 157 of which were selected by title and abstract. After full-text reading, sixteen articles were selected. The evidence quality for all the studies was moderate. Conclusions ROA induced a temporary increase of Candida counts from the early stage of treatment but which returned to the pre-treatment level after ROA removal. Contrasting results were reported for FOA treatment which promoted the oral colonisation of non-albicans species, although the most prevalent species was Candida albicans in both groups. This review should be interpreted with caution because of the number, quality, and heterogeneity of the included studies.