Effect of Probiotic Tablets and Topical Probiotic Oil (Lactobacillus. Reuteri) on Oral Wound Healing (Pilot Study)

Intervention: after informed consent and baseline collection of clinical data (age,sex), the participants will be randomly assigned to one of the order of the treatments. As a run-in period, they will be given a supply of probiotic or placebo tablets enough for seven days. The participants are instructed to take two tablets daily (one in the morning and one in the evening, days 0-7) and are asked to refrain from any other foods or supplements containing probiotics. On day eight, the participant will attend to the clinics and a punch biopsy will be performed. Depending on the allocation group, probiotic or placebo oil will be supplied. The participant will be instructed to apply the oil locally on the wound with a plastic microbrush for 9 days every evening, and strongly reinforced to continue with the assigned tablets twice daily. The participant will attend the clinics on days two, five and eight post-wounding for follow-up photographies of wound healing. The first intervention period terminates with a wash-out period of four weeks, and then the second run-in an intervention period start following the same procedures.

The probiotic tablets and the probiotic oil (at the recommended dose) contain 2x10^8 CFU of Lactobacillus reuteri. Both the placebo tablets and oil are identical in size and composition but without the addition of the probiotic strains. The tablets and oil are packed in identical pots/bottles with color coding. The code will be kept from the investigators until the analysis are finished. Both the tablets and oil are provided by BIOGAIA AB.

Clinical procedures and sampling

All clinical procedures and sample collections will be conducted by a qualified and authorized dentist from the Institute of Odontology, Section for Cariology, Endodontics, Pediatric Dentistry and Clinical Genetics, Faculty of Health and Medical Sciences, University of Copenhagen. Collected samples (saliva, wound exudate and bacterial smear) will be stored in a freezer at -80 °C until all samples from all patients are gathered -for a maximum of six months. Running of all collected samples at the same time allows laboratory analyses to be carried out efficiently and avoids errors.

Punch biopsy: on day eight, a standardized circular wound of 3.5 mm diameter and approximately 1.5 mm deep will be created in the mucosa of the hard palate with aid of a biopsy punch. The biopsy is performed under aseptic conditions and local anesthesia using lidocaine 2% combined with epinephrine for local hemostasis. A scalpel is used to remove the surface epithelium and underlying superficial connective tissue, which will be discarded according to biosafety regulations from the Institute of Dentistry, University of Copenhagen. After wounding, the wound site will be photographed (blind-coded) with an intraoral camera, placing a standard-sized 6 mm diameter template around the wound as reference. The participant will attend to the dental clinics on days two, five and eight post-wounding to have a photograph of the wound taken by Ph.D student Gina Castiblanco. The wound-size on photographs will be measured by two raters and will be expressed as the ratio of the wound surface area relative to the standard label size with aid of software (Canvas 7, ACD Systems of America). The endpoint will be the percentage of initial wound size, measured at days two, five and eight post-wounding.