In search for natural products with antimicrobial properties for use in the prevention and treatment of peri-implantitis, the purpose of this investigation was to evaluate the antimicrobial activity of curcumin and xanthohumol, using an in vitro multi-species dynamic biofilm model including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of curcumin (5 mM) and xanthohumol (100 μM) extracts, and the respective controls, were evaluated with 72-h biofilms formed over dental implants by their submersion for 60 seconds. The evaluation was assessed by quantitative polymerase chain reaction (qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). For the data analysis, comparisons were tested applying ANOVA tests with post-hoc Bonferroni corrections to evaluate the antimicrobial activity of both extracts. With qPCR, statistically significant reductions in bacterial counts were observed for curcumin and xanthohumol, when compared to the negative control. The results with CLSM and SEM were consistent with those reported with qPCR. It was concluded that both curcumin and xanthohumol have demonstrated antimicrobial activity against the six bacterial species included in the dynamic in vitro biofilm model used.

Microbial biofilm modeling has improved in sophistication and scope, although only a limited number of standardized protocols are available. This review presents an example of a biofilm model, along with its evolution and application in studying periodontal and peri-implant diseases. In 2011, the ETEP (Etiology and Therapy of Periodontal and Peri-Implant Diseases) research group at the University Complutense of Madrid developed an in vitro biofilm static model using representative bacteria from the subgingival microbiota, demonstrating a pattern of bacterial colonization and maturation similar to in vivo subgingival biofilms. When the model and its methodology were standardized, the ETEP research group employed the validated in vitro biofilm model for testing in different applications. The evolution of this model is described in this manuscript, from the mere observation of biofilm growth and maturation on static models on hydroxyapatite or titanium discs, to the evaluation of the impact of dental implant surface composition and micro-structure using the dynamic biofilm model. This evolution was based on reproducing the ideal microenvironmental conditions for bacterial growth within a bioreactor and reaching the target surfaces using the fluid dynamics mimicking the salivary flow. The development of this relevant biofilm model has become a powerful tool to study the essential processes that regulate the formation and maturation of these important microbial communities, as well as their behavior when exposed to different antimicrobial compounds.

The primary objective was to assess the safety of a new toothpaste formulation containing cetylpyridinium chloride (CPC) and cymenol as active agents. In addition, clinical efficacy and patient perception were evaluated. A 6-week randomized clinical trial was designed and patients were randomly allocated to use a test or control dentifrice. Adverse effects were assessed at 3- and 6-week follow-up visits, together with the following clinical parameters: Turesky plaque index (PlI), bleeding on marginal probing (BOMP), bleeding on probing (BOP) and Gründemann modification of the stain index (GMSI). Patient-reported outcome measures (PROMs) were also evaluated. A total of 60 patients were randomized and 55 were finally included in the analysis (test, 29; control, 26). Both toothpastes were safe and well tolerated by the patients. Statistically significant differences between test and control groups were observed for BOP changes between baseline week 6 (p = 0.031) and lower levels of plaque were registered in the test group at the 3- and 6-week visits (p < 0.05). No differences were observed for staining or PROMs. The use of a toothpaste containing CPC and cymenol was safe and not associated with any adverse effects. Significantly better clinical results were observed for the test group in terms of PlI levels and BOP reductions.

Multiple toothbrush designs have been developed to enhance dental biofilm removal and decrease bacterial contamination and retention over time. Therefore, the aim of this clinical study was to compare the efficacy of a prototype of a new double-sided thermoplastic polyurethane-based toothbrush with that of a conventional nylon-bristle toothbrush. A crossover study was conducted in systemically healthy volunteers (n = 24) for two one-week periods plus one washout week. As outcome variables, plaque and gingival indices, total bacterial contamination of the toothbrushes by quantitative polymerase chain reaction (qPCR), and patient-reported outcomes were measured. Clinical and microbiological variables were analysed using a general linear model and Friedman and Wilcoxon signed-rank tests. No statistically significant differences between toothbrushes were detected neither for full-mouth PlI (p > 0.05) nor for GI (p > 0.05). Similarly, no statistically significant differences were detected for bacterial contamination after 40 seconds or 1 week of use, with results expressed either in CFU/mL or in CFU/mm² (p > 0.05). In conclusion, the tested prototype toothbrush was as effective and safe as the control toothbrush, and the participating subjects did not experience any adverse effects from its use and rated its efficiency and effectiveness in cleaning their teeth as satisfactory.

The aim of this study was to evaluate a newly formulated mouth rinse containing cymenol in patients undergoing supportive periodontal care in terms of safety (primary outcome) and the impact on dental biofilm and gingival inflammation (secondary outcomes). This research was designed as a pilot, controlled, randomized, parallel, triple-blinded, single-center, clinical trial of a 12-week duration. Adverse events and product perception were assessed by a questionnaire. Clinical, patient-reported outcomes (PROs), compliance, tooth staining, dentin hypersensitivity and microbiological variables were also evaluated. Student T, Mann–Whitney-U and Chi-square tests were applied. Thirty participants (15 per group) were included, randomized and followed for 12 weeks. No adverse events were reported. The questionnaire showed an overall rating of 7.2 (out of 10) in the experimental group and of 8.2 in the control group (p = 0.165) at 12 weeks. No statistically significant differences were observed in terms of gingival health, tooth staining, dentin hypersensitivity or microbiological outcomes between groups at baseline, 6- and 12-week visits. The adjuvant use of the new mouth rinse formulation proved to be as safe as the control product and no significant differences were observed in terms of clinical efficacy.