Robert J. Gambogi

A randomized trial of ethyl lauroyl arginate‐containing mouthrinse in the control of gingivitis

Abstract Aim This 4‐week, single‐centre, randomized, examiner‐blind, controlled study investigated the efficacy and safety of 0.15% ethyl lauroyl arginate (LAE)‐containing mouthrinse in adults with mild‐to‐moderate gingivitis. Material and Methods Subjects were randomized to use 0.15% LAE‐containing mouthrinse or 5% hydroalcohol‐negative control twice daily after brushing with standard fluoride toothpaste. Plaque, gingivitis and bleeding were assessed at baseline and Weeks 2 and 4. The oral microflora was analysed at baseline and Week 4. Results Eighty‐seven subjects were randomized to treatment. The 0.15% LAE‐containing mouthrinse was associated with statistically significantly (p < 0.001) greater reductions in mean plaque and gingivitis scores versus the negative control at Week 2 (difference [95% confidence interval]: plaque 0.83 [0.64, 1.02], 29.1%; gingivitis 0.11 [0.07, 0.14], 4.8%) and Week 4 (co‐primary endpoints: plaque 1.23 [1.07, 1.39], 42.6%; gingivitis 0.23 [0.19, 0.28], 10.7%). Bleeding‐index scores were significantly (p < 0.001) reduced versus the control at Weeks 2 (by 0.04 [0.03, 0.06], 36.3%) and 4 (by 0.06 [0.04, 0.08], 50.9%). No shifts were detected in the oral microflora. There were no treatment‐related adverse events. Conclusions The 0.15% LAE‐containing mouthrinse was well tolerated and significantly reduced plaque, gingivitis and bleeding when used as an adjunct to tooth brushing for 4 weeks.

Impact of an Anticaries Mouthrinse on In Vitro Remineralization and Microbial Control

Objective. The objective of this research was to evaluate the caries control potential of a new fluoride mouthrinse that also contained antimicrobial agents and a biofilm disrupting agent using different in vitro models. Methods. Four in vitro studies were conducted to assess the performance of this three pronged approach to caries control: (1) traditional enamel fluoride uptake, (2) surface microhardness study using pH cycling model and subsequent fluoride uptake, (3) a salivary biofilm flow-through study to determine the anti-microbial activity, and (4) a single species biofilm model measuring effect on biofilm matrix disruption. Results. The data showed that a LISTERINE rinse with fluoride, essential oils and xylitol was superior in promoting enamel fluoride uptake and in enhancing antimicrobial activity over traditional commercially available fluoridated products. An increase of the surface microhardness was observed when the LISTERINE rinse was used in combination with fluoridated toothpaste versus the fluoridated toothpaste alone. Finally, it was demonstrated that xylitol solutions disrupted and reduced the biovolume of biofilm matrix of mature Streptococcus mutans. Conclusion. These in vitro studies demonstrated that a fluoride mouthrinse with antimicrobial agent and biofilm matrix disrupting agent provided multifaceted and enhanced anti-caries efficacy by promoting remineralization, reducing acidogenic bacteria and disrupting biofilm matrix.

Diminishing biofilm resistance to antimicrobial nanomaterials through electrolyte screening of electrostatic interactions

The extracellular polymer substances (EPS) generated by biofilms confers resistance to antimicrobial agents through electrostatic and steric interactions that hinder molecular diffusion. This resistance mechanism is particularly evident for antibacterial nanomaterials, which inherently diffuse more slowly compared to small organic antibacterial agents. The aim of this study was to determine if a biofilms resistance to antibacterial nanomaterial diffusion could be diminished using electrolytes to screen the EPSs electrostatic interactions. Anionic (+) alpha-tocopherol phosphate (α-TP) liposomes were used as the antimicrobial nanomaterials in the study. They self-assembled into 700 nm sized structures with a zeta potential of -20 mV that were capable of killing oral bacteria (S. oralis growth inhibition time of 3.34 ± 0.52 h). In a phosphate (-ve) buffer the -ve α-TP liposomes did not penetrate multispecies oral biofilms, but in a Tris (hydroxymethyl)aminomethane (+ve) buffer they did (depth - 12.4 ± 3.6 μm). The Tris did not modify the surface charge of the α-TP nanomaterials, rather it facilitated the α-TP-biofilm interactions through electrolyte screening (Langmuir modelled surface pressure increase of 2.7 ± 1.8 mN/ m). This data indicated that EPS resistance was mediated through charge repulsion and that this effect could be diminished through the co-administration of cationic electrolytes.

In vitro efficacy of essential oil mouthrinse versus dentifrices

OBJECTIVES To compare the antimicrobial efficacy and kill penetration of essential oils (EO) mouthrinse versus stannous fluoride, and triclosan dentifrice slurries on saliva-derived biofilms using confocal laser scanning microscopy (CLSM). METHODS Saliva-derived biofilms were grown for 48h on hydroxyapatite discs using pooled, homogenized saliva from 8 healthy volunteers as the inoculum. The mean thickness of these biofilms was 84μm (range, 23-241μm). CLSM with viability mapping was used to visualize the antimicrobial kill penetration of each treatment regime within a biofilm. RESULTS At 30s treatment durations, CLSM imaging revealed greater antimicrobial activity and kill penetration of EO mouthrinse compared to sodium fluoride-, stannous fluoride-, and triclosan-containing dentifrice slurries. Quantification of biovolume revealed that EO mouthrinse treatment at 30s resulted in a greater non-viable biovolume proportion (84.6%±15.0%) than other treatment groups. Increasing the treatment duration of the triclosan dentifrice (to 60 and 120s) resulted in better penetration and an increased reduction of viable cells, comparable to EO mouthrinse treatment at 30s duration. Further, CLSM imaging showed that the combined treatment of a non-antimicrobial dentifrice (45s) with EO mouthrinse (30s) showed superior antimicrobial activity (96.2%±3.7%) compared to the antimicrobial triclosan-containing dentifrice used without a mouthrinse step (26.0%±32.0%). CONCLUSIONS Within typical exposure times, the EO-containing mouthrinse can penetrate deep into the accumulating plaque biofilm compared to the chemotherapeutic dentifrice slurries, and may provide an efficacious alternative to triclosan, when used as an adjunct with a mechanical oral care regimen. CLINICAL SIGNIFICANCE Using viability mapping and CLSM, this study demonstrated that EO-containing mouthrinse penetrates and kills microorganisms deeper and more effectively in plaque biofilm in typical exposure times when compared to dentifrice chemotherapeutic agents, providing an efficacious alternative to triclosan or stannous fluoride when used as an adjunct to mechanical oral care.