A single M-EO is an effective measure against the de novo biofilm, presenting a good alternative to clorhexidine such as a preoperative rinse, in periodontal procedures or post-treatment applications.

ObjectiveTo evaluate the in situ antibacterial activity of a mouthrinse with 0.2% Chlorhexidine (M-0.2% CHX) on undisturbed de novo plaque-like biofilm (PL-biofilm) and on salivary flora up to 7 hours after its application.MethodsA special acrylic appliance was designed, with 3 inserted glass disks on each buccal side, allowing for PL-biofilm growth. Fifteen healthy volunteers wore the appliance for 48 hours and then performed an M-0.2% CHX; disks were removed at 30 seconds and 1, 3, 5 and 7 hours after the mouth-rinsing. Applying a washout period, saliva samples were collected from each volunteer at 30 seconds and 1, 3, 5 and 7 hours after performing an M-0.2% CHX. The PL-biofilm and saliva samples were analysed by confocal laser scanning and epifluorescence microscopes, respectively.ResultsAt 30 seconds after M-0.2% CHX, the levels of viable bacteria detected in saliva were significantly lower than those observed in PL-biofilm. The difference in the percentage of live bacteria detected in saliva was significantly higher than that observed in PL-biofilm at 5 and 7 hours after M-0.2% CHX.ConclusionAfter a single mouthrinse of the 0.2% CHX formulation tested in the present study, the 2-day PL-biofilm presented a significantly higher resistance to this antiseptic in situ than that observed in salivary flora. However, this 0.2% CHX formulation showed a higher substantivity on PL-biofilm than on salivary flora at 5 and 7 hours after mouth-rinsing, which could be related to the slower growth rate of PL-biofilm and the possible reservoir function for antimicrobial agents associated with the undisturbed de novo PL-biofilm.

ObjectiveTo evaluate the in situ antiplaque effect after 4 days of using of 2 commercial antimicrobial agents in short term on undisturbed plaque-like biofilm.Trial Design and ParticipantsAn observer-masked, crossover randomised clinical trial on 15 oral and systemically healthy volunteers between 20–30 years who were randomly and sequentially allocated in the same group which performed 3 interventions in different randomised sequences.InterventionThe participants wore an appliance in 3 different rinsing periods doing mouthwashes twice a day (1/0/1) with essential oils, 0.2% chlorhexidine or sterile water (negative control). At the end of each 4-day mouthwash period, samples were removed from the appliance. Posteriorly, after bacterial vital staining, samples were analysed using a Confocal Laser Scanning Microscope.Main Outcome MeasuresBacterial vitality, thickness and covering grade by the biofilm after 4 days of applying each of the mouthwashes.ResultsThe essential oils and the 0.2% chlorhexidine were significantly more effective than the sterile water at reducing bacterial vitality, thickness and covering grade by the biofilm. No significant differences were found between the 0.2% chlorhexidine and the essential oils at reducing the bacterial vitality (13.2% vs. 14.7%). However, the 0.2% chlorhexidine showed more reduction than the essential oils in thickness (6.5 μm vs. 10.0 μm; p<0.05) and covering grade by the biofilm (20.0% vs. 54.3%; p<0.001).ConclusionThe essential oils and 0.2% chlorhexidine showed a high antiplaque effect. Although the 0.2% chlorhexidine showed better results with regard to reducing the thickness and covering grade by the biofilm, both antiseptics showed a high and similar antibacterial activity.Clinical RelevanceDaily essential oils or 0.2% chlorhexidine mouthwashes are effective when reducing dental plaque formation in the short term. Although 0.2% chlorhexidine continues to be the “gold standard” in terms of antiplaque effect, essential oils could be considered a reliable alternative.Trial RegistrationClinicalTrials.gov NCT02124655

Audi tory processing and phonemic discrimination are essential for communication. Type of study: Retrospective. Aim:To evaluate auditory processing and phonemic discrimination in children with normal and disordered phonological development. Material and Methods:An evaluation of 46 children was carried out: 22 had phonological disorders and 24 had normally developing speech. Diotic , monotic and dichotic tests were applied to assess auditory processing and a test to evaluate phonemic discrimination abilities.Design: Cross-sectional, contemporary. Results:The values of normally-developing children were within the normal range in all auditory processing tests; these children attained maximum phonemic discrimination test scores. Children with phonological disorders performed worse in the latter, and presented disordered auditory processing. Conclusion:Auditory processing and phonemic discrimination in children with phonological disorders are altered. Braz J Otorhinolaryngol. 2010;76(6):762-8. ORIGINAL ARTICLE BJORL

Currently, there is little evidence on the in situ antibacterial activity of essential oils (EO) without alcohol. This study aimed to evaluate in situ the substantivity and antiplaque effect on the plaque-like biofilm (PL-biofilm) of two solutions, a traditional formulation that contains EO with alcohol (T-EO) and an alcohol-free formulation of EO (Af-EO). Eighteen healthy adults performed a single mouthwash of: T-EO, Af-EO, and sterile water (WATER) after wearing an individualized disk-holding splint for 2 days. The bacterial viability (BV) and thickness of the PL-biofilm were quantified at baseline, 30 s, and 1, 3, 5, and 7 h post-rinsing (Test 1). Subsequently, each volunteer wore the splint for 4 days, applying two daily mouthwashes of: T-EO, Af-EO, and WATER. The BV, thickness, and covering grade (CG) of the PL-biofilm were quantified (Test 2). Samples were analyzed by confocal laser scanning microscopy after staining with the LIVE/DEAD® BacLight™ solution. To conduct the computations of the BV automatically, a Matlab toolbox called Dentius Biofilm was developed. In test 1, both EO antiseptics had a similar antibacterial effect, reducing BV after a single rinse compared to the WATER, and keeping it below baseline levels up to 7 h post-rinse (P < 0.001). The mean thickness of the PL-biofilm after rinsing was not affected by any of the EO formulations and ranged from 18.58 to 20.19 μm. After 4 days, the T-EO and Af-EO solutions were significantly more effective than the WATER, reducing the BV, thickness, and CG of the PL-biofilm (P < 0.001). Although, both EO antiseptics presented a similar bactericidal activity, the Af-EO rinses led to more significant reductions in the thickness and CG of the PL-biofilm than the T-EO rinses (thickness = 7.90 vs. 9.92 μm, P = 0.012; CG = 33.36 vs. 46.61%, P = 0.001). In conclusion, both essential oils antiseptics had very high immediate antibacterial activity and substantivity in situ on the 2-day PL-biofilm after a single mouthwash. In the 4-day PL-biofilm, both essential oils formulations demonstrated a very good antiplaque effect in situ, although the alcohol-free formula performed better at reducing the biofilm thickness and covering grade.