The effects of essential oil mouthrinses with or without alcohol on plaque and gingivitis: a randomized controlled clinical study.

BACKGROUND: The efficacy of several variants of essential oil mouthrinses has been studied extensively. This is the first study to compare the anti-plaque and anti-gingivitis efficacy of two marketed essential oil mouthrinses: one is an alcohol containing mouthrinse and the other one is an alcohol-free mouthrinse. METHODS: This examiner-blind, parallel-group study randomized subjects to three groups: 1) Mechanical Oral Hygiene (MOH) only; 2) MOH plus Alcohol-Containing essential oil Mouthrinse (ACM); 3) MOH plus Alcohol-Free essential oil Mouthrinse (AFM). Primary endpoint was whole-mouth mean Modified Gingival Index (MGI) at six months. Secondary endpoints included whole-mouth mean MGI at one and three months, and whole-mouth mean Plaque Index (PI) and whole-mouth mean Bleeding Index (BI) at one, three and six months. Safety assessments were conducted at all time points. RESULTS: A total of 370 subjects were enrolled; 348 subjects completed the study. After six months, subjects using essential oil mouthrinses with or without alcohol showed significant reduction (p < 0.001) in gingivitis (28.2% and 26.7%, respectively) and significant reduction (p < 0.001) in plaque (37.8% and 37.0%, respectively), compared to those performing MOH only. Significant reductions in MGI, PI, and BI (p < 0.001) were observed at one and three months and also at six months for mean BI. No statistically significant differences were observed for all measured indices between ACM and AFM groups at any time point. Both mouthrinses were well tolerated. CONCLUSIONS: No significant differences were observed in the efficacy of ACM and AFM to reduce plaque and gingivitis, when used in addition to MOH, over six months. TRIAL REGISTRATION: The trial was registered on clinicaltrials.gov on November 30, 2016. The registration number is NCT02980497 .

Excited-state electronic coupling and photoinduced multiple electron transfer in two related ligand-bridged hexanuclear mixed-valence compounds.

The synthesis, characterization, electrochemical, photophysical, and photochemical properties of two hexanuclear mixed-valence compounds are reported. Each supramolecular species consists of two cyano-bridged [(NC)(5)Fe(II)-CN-Pt(IV)(NH(3))(3)L-NC-Fe(II)(CN)(5)] triads that are linked to each other through a Pt(IV)-L-Pt(IV) bridge, where L = 4,4'-dipyridyl (bpy) or 3,3'-dimethyl-4,4'-dipyridyl (dmb). The major difference between the two compounds is the electronic nature of the bridging ligand between the two Pt atoms. Both species exhibit a broad Fe(II) --> Pt(IV) intervalent (IT) absorption band at 421 nm with an oscillator strength that is approximately four times that for [(NC)(5)Fe(II)-CN-Pt(IV)(NH(3))(5)] and twice that for [(NC)(5)Fe(II)-CN-Pt(IV)(NH(3))(4)-NC-Fe(II)(CN)(5)].(4-) When L = bpy, the resonance Raman spectrum obtained by irradiating the IT band at 488 nm exhibits several dipyridyl ring modes at 1604, 1291, and 1234 cm(-1) which are not present in the spectrum when L = dmb. In addition, femtosecond pump-probe spectroscopy performed at 400 nm yields a transient bleach of the IT absorption band with a single exponential decay of 3.5 ps for L = bpy, compared with only 1.8 ps for L = dmb and 2.1 ps for [(NC)(5)Fe(II)-CN-Pt(IV)(NH(3))(4)-NC-Fe(II)(CN)(5)].(4-) Last, prolonged irradiation of the complexes at 488 nm leads to the formation of 4 equiv of ferricyanide with a quantum efficiency of 0.0014 for L = bpy and 0.0011 for L = dmb. The transient absorption, resonance Raman, and photochemical data suggest that the degree of excited electronic coupling in these compounds is tunable by changing the electronic nature of the Pt-L-Pt bridging ligand.