Effect of chlorhexidine varnish on gingival growth in orthodontic patients: a randomized prospective split-mouth study

INTRODUCTION: Fixed orthodontic appliances patients suffer limitations on the effective control of biofilm by mechanical methods, bringing the need of a coadjutant in the control of inflammation and oral health improvement. OBJECTIVE: The aim of this prospective split-mouth blind study was to analyze the effect of a 40% chlorhexidine (CHX) varnish on gingival growth of patients with orthodontic fixed appliances. Methods: Healthy teenage patients with fixed orthodontic appliances and increased gingival volume were recruited (n = 30). Each individual was his own control, having in the maxilla one control side and one treatment side. An application of varnishes occurred on the vestibular area of the upper premolars and first molar crowns, on the control side (placebo varnish) and on the experimental side (EC40((r)) Biodentic CHX varnish). The varnishes and sides were randomly chosen and its identification and group was kept by a third party observer and it was not revealed to the researchers and participants until the end of study. In order to establish a baseline registration, digital photographs were taken by a trained photographer before varnish application at baseline (T(0)), as well as 14 days (T(14)) and 56 days (T(56)) after the application. The gingival volume was calculated indirectly using the vestibular areas (mm(2)) of the upper second premolars' clinical crowns by RapidSketch((r)) software, at all study times. The data were analyzed using ANOVA and the Turkey-Krammer test. RESULTS: It was observed, in the final sample of 30 individuals, that at T(0), the control and treatment groups were similar. At T(14) and T(56), a progressive reduction of the clinical crown area was seen in the control group, and an increase in the average area was detected in the experimental group (p < 0,05). CONCLUSIONS: The use of 40% CHX varnish decreases the gingival overgrowth in patients undergoing orthodontic treatment. Further studies are necessary to set the action time and frequency of application.