Abstract The objective of this study was to evaluate the in vitro effects, including surface morphological characteristics and chemical elemental properties, of different mouthwash formulations on enamel and dental restorative materials, simulating up to 6 months of daily use. Human enamel samples, hydroxyapatite, composite resin, and ceramic surfaces were exposed to 3 different mouthwashes according to label directions — Listerine® Cool Mint®, Listerine® Total Care, and Listerine® Whitening — versus control (hydroalcohol solution) to simulate daily use for up to 6 months. The samples were analyzed using scanning electron microscopy (SEM), infrared spectrophotometry (µ-Fourier transform infrared microscopy), energy-dispersive X-ray (EDX) spectroscopy, and color analysis before and after exposure. No relevant changes were observed in the morphological characteristics of the surfaces using SEM techniques. The physical and chemical aspects of the enamel surfaces were evaluated using mid-infrared spectroscopy, and EDX fluorescence was used to evaluate the elemental aspects of each surface. There was no variation in the relative concentrations of calcium and phosphorus in enamel, silicon and barium in composite resin, and silicon and aluminum in the ceramic material before and after treatment. No relevant changes were detected in the biochemical and color properties of any specimen, except with Listerine® Whitening mouthwash, which demonstrated a whitening effect on enamel surfaces. Long-term exposure to low pH, alcohol-containing, and peroxide-containing mouthwash formulations caused no ultra-structural or chemical elemental changes in human enamel or dental restorative materials in vitro.

Two antimicrobial agents, a fixed combination of essential oils (EOs) and 0.07% cetylpyridinium chloride (CPC) are found in commercially available mouthrinses, Listerine® Antiseptic and Crest® Pro HealthTM, respectively. Both mouthrinses have been shown to control dental plaque and gingivitis in short and longer term studies. The aim of this study was to determine the comparative effectiveness of these two mouthrinses using a 2-week experimental gingivitis model. Qualified subjects were randomly assigned to one of three mouthrinse groups: a fixed combination of EOs, 0.07% CPC, or negative control (C) rinse. Following baseline clinical assessments and a dental prophylaxis, subjects began a two-week period in which they rinsed twice daily with their assigned rinse and abstained from any mechanical oral hygiene procedures or other oral care products. Subjects were reassessed at the end of the two-week period. One hundred and forty-seven subjects were randomized and 142 completed this study. After two weeks use, the EOs rinse was superior (p < 0.011) to the CPC rinse in inhibiting the development of gingivitis, plaque, and bleeding, with 9.4% and 6.6% reductions compared to CPC for gingivitis and plaque, respectively. Both rinses were superior to the negative control rinse (p < 0.001). This study demonstrates that the essential oil-containing mouthrinse has superior antiplaque/antigingivitis effectiveness compared to the 0.07% CPC-containing mouthrinse without mechanical oral hygiene influence.

The objective of this randomized, examiner blind, parallel group, controlled clinical trial was to compare the antiplaque and antigingivitis efficacy of an essential oil-containing mouthrinse (EO) to two mouthrinses containing 0.05% Cetylpyridinium Chloride (CPC), one with alcohol and one alcohol-free, using a two-week experimental gingivitis validated-model with a 5% hydroalcohol rinse serving as the negative control. One hundred and fifty-nine subjects, 56 males and 103 females; ranging in age from 18 to 58 years in good general health were assigned to one of the four treatment groups: EO (n = 40), 0.05% CPC with alcohol (CPCa, n = 39), 0.05% CPC alcohol-free (CPCna, n = 40), and 5% hydroalcohol negative control (n = 40). The Mean Turesky Modification of the Quigley-Hein Plaque Index (PI) and the Mean Modified Gingival Index (MGI) were the primary efficacy endpoints and were evaluated at baseline and at two weeks. Following baseline examinations, subjects received a complete dental prophylaxis and began supervised rinsing with their assigned mouthrinse twice daily for two weeks, as their sole oral hygiene measure; 151 subjects completed the trial. Two weeks after baseline the EO adjusted mean PI and MGI scores were significantly lower than those of both CPC rinses and negative control (p < 0.001). In conclusion, the EO mouthrinse demonstrated significantly greater antiplaque and antigingivitis efficacy than both CPC-containing mouthrinses and the negative control.