Acrylic orthodontic retainer is not a risk factor for focal Candida colonization in young healthy patients: A pilot study

Background Denture enhances the risk of Candida colonization because of adherence to acrylic base and interference with salivary rinsing. Acrylic orthodontic appliances may also create retentive areas for food debris and microbial pathogens; moreover, patients are instructed to use the retainers at night, when salivary secretion is reduced. We studied the Candida colonization in orthodontic patients using acrylic retainer. Methods Participants were orthodontic patients with full compliance during the retention phase with no signs or symptoms or being at risk for Candida, divided into users of (a) Hawley retainer (study group) and (b) other retainers (vacuum-formed/fixed bonded retainer; control group). Collected data included demographic characteristics and habits. Samples were collected from palate mucosa, cultured and incubated (28°C) for 3 days. Positive Candida species were recultured to identify the Candida species. Results Fifty-one patients participated (mean age 20.9 ± 9.6 years); 22 had maxillary Hawley retainer and 29 had maxillary vacuum-formed/fixed bonded retainer. Candida albicans colonization in the hard palate was identified in 2 patients (3.9%) - 1 (4.5%) from the Hawley retainer study group and 1 (3.4%) from the control group. Conclusions The hypothesis that palatal coverage by acrylic orthodontic retainer might enhance Candida colonization on the palatal mucosa is not supported by this pilot study.