Salivary pellicle modulates biofilm formation on titanium surfaces.

OBJECTIVES: The present study aimed to evaluate the potential of the salivary pellicle (SP) formed on titanium (Ti) surfaces to modulate the formation of a biofilm composed of Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis. MATERIALS AND METHODS: Ti substrates were incubated for 2 h with a pool of saliva samples obtained from 10 systemically and periodontally healthy subjects. Enamel substrates were included as a biological reference. Scanning electron microscopy (SEM) and Raman spectroscopy analysis were used to analyze the formation of the salivary pellicle. After the SP formation, the surfaces were incubated for 12 h with a mix of Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis. The number of bacterial cells attached to each surface was determined by the XTT assay while bacterial viability was analyzed by fluorescence microscopy using the LIVE/DEAD® BacLightTM kit. RESULTS: The SEM and Raman spectroscopy analysis confirmed the presence of a salivary pellicle formed on the tested surfaces. Regarding the biofilm formation, the presence of the SP decreases the number of the bacterial cells detected in the test surfaces, compared with the uncover substrates. Even more, the SP-covered substrates showed similar bacterial counts in both Ti and enamel surfaces, meaning that the physicochemical differences of the substrates were less determinant than the presence of the SP. While on the SP-uncover substrates, differences in the bacterial adhesion patterns were directly related to the physicochemical nature of the substrates. CONCLUSIONS: The salivary pellicle was the main modulator in the development of the biofilm consisting of representative oral bacteria on the Ti substrates. CLINICAL RELEVANCE: The results of this study provide valuable information on the modulatory effect of the salivary pellicle on biofilm formation; such information allows us to understand better the events involved in the formation of oral biofilms on Ti dental implants.

Probiotic Monotherapy with Lactobacillus reuteri (Prodentis) as a Coadjutant to Reduce Subgingival Dysbiosis in a Patient with Periodontitis.

(1) Background: Probiotics can be considered a non-invasive periodontal monotherapy for the modulation of microbiota when periodontal treatment is not accessible. The aim was to evaluate the ability of Lactobacillus reuteri Prodentis as monotherapy to modulate periodontal parameters and subgingival biofilm dysbiosis. (2) Methods: A 30-year-old patient with periodontitis was followed longitudinally after one month of daily consumption of L. reuteri Prodentis (T0). Periodontal measurements and microbial identification by Checkerboard DNA−DNA hybridization of 40 bacteria were compared between baseline (T0) and 30 days (T1) or 90 days (T2), using the Kruskal−Wallis (KW) and Mann−Whitney U (MW) tests. (3) Results: Low values of pocket depth, attachment level, dental plaque, gingival erythema (GE), and suppuration were observed at T0 vs. T1, with the clinical improvement of GE (p < 0.05, MW) and the recovery of tooth 46 fistulation. T1 vs. T0 comparisons showed lower levels (Lev) or proportions (Prop) of Parvimonas micra (Lev: p < 0.05, MW; Prop: p < 0.01, MW) and Streptococcus gordonii (Prop: p < 0.05, MW), and a predominance (Lev/Prop) of Actinomyces odontolyticus and Streptococcus mitis; lower levels and proportions of P. micra, Eubacterium saburreum, Porphyromonas gingivalis, and Tannerella forsythia were observed in tooth 46 (T1/T2 vs. T0). (4) Conclusions: Under monotherapy with L. reuteri Prodentis, periodontal measurements of the patient were maintained, with selective changes in the subgingival microbiota that were proportional to the time of probiotic administration, with any additional periodontal treatment.

Roughness and wettability of titanium implant surfaces modify the salivary pellicle composition.

This study reports the differences in the protein composition of salivary pellicles formed under in situ conditions on two Titanium (Ti) surfaces, with different roughness and wettability. Smooth pretreatment Ti surfaces (Ti-PT) with an average roughness (Ra) of 0.45 µm and a water contact angle (WCA) of 92.4°, as well as a more rough sandblasted, large grit, acid-etched treatment Ti surfaces (Ti-SLA) with a Ra of 3.3 µm and WCA of 131.8°, were tested. The salivary pellicles were quantitatively analyzed by bicinchoninic acid assays, and the protein identification was performed by Nano-LC-MS/MS (nano mass spectrometry). Protein levels of 2.5, and 9.1 µg/ml were quantified from the detached salivary pellicle formed on the Ti-PT and Ti-SLA surfaces, respectively. Using Nano-LC-MS/MS, a total of 597 proteins were identified on all the substrates tested; 43 proteins were identified only on the Ti-PT, and 226 proteins were adsorbed solely on the Ti-SLA substrates. The physicochemical characteristics of the Ti implant surfaces modified the amount and the identity of the salivary proteome of the pellicles formed, confirming the high selectivity of the protein pellicle formed on a surface once is exposed in the oral cavity.

Antibacterial activity of a glass ionomer cement doped with copper nanoparticles.

Copper nanoparticles (NCu) were synthetized and added to commercial glass ionomer cement, to evaluate in vitro its antibacterial activity against oral cavity strains. The NCu were synthesized by copper acetate reduction with L-ascorbic acid and characterized by FTIR, Raman, XPS, XRD and TEM. Then, commercial glass ionomer cement (GIC) was modified (MGIC) with various concentrations of NCu and physicochemically characterized. Cell viability was tested against human dental pulp fibroblasts (HDPFs) by Alamar-Blue assay and antibacterial test was performed against S. mutans and S. sanguinis by colony forming unit (CFU) growth method. Synthesized NCu rendered a mixture of both metallic copper and cuprous oxide (Cu2O). HDPF viability reduces with exposure time to the extracts (68-72% viability) and MGIC with 2-4 wt% NCu showed antimicrobial activity against the two tested strains.

Chlorhexidine rinsing inhibits biofilm formation and causes biofilm disruption on dental enamel in situ.

OBJECTIVES: This in situ study aims to evaluate the effects of chlorhexidine (CHX) mouth rinsing on biofilm formation and moreover on the disruption of existing mature dental biofilms. METHODS: Biofilms were formed in situ by five volunteers on bovine enamel specimens fixed to individual acrylic splints. For biofilm formation analysis, the volunteers intraorally exposed the splint for 48 h. Mouth rinsing using 10 ml of 0.2% CHX or water as control was performed for 30 s every 12 h. For analysis of biofilm disruption, the biofilm was formed on enamel specimens for 48 h. Then, the first CHX rinse was carried out. A second rinse followed after an additional 12 h, again for 30 s using 10 ml of 0.2% CHX. Biofilm vitality was imaged by fluorescence microscopy after vital fluorescence staining. Additionally, the ultrastructure of the biofilm was examined by transmission electron microscopy. RESULTS: Rinses with 0.2% CHX significantly reduced biofilm formation on enamel. Both biofilm colonization and vitality were dramatically impaired. Moreover, a considerable biofilm disruption induced by the CHX rinses was observed. Remarkably, a single application of CHX to a 48-h mature biofilm causes biofilm ultrastructure alterations and induces a substantial reduction in biofilm thickness and bacterial vitality. CONCLUSIONS: CHX mouth rinses induced a significant inhibition of biofilm formation on native enamel. Furthermore, an important biofilm disrupting effect under in situ conditions was detected. CLINICAL RELEVANCE: CHX rinses could be used as a short-term treatment protocol for biofilm management focused on patients unable to reach adequate oral hygiene.

Influence of the Periodontal Status on the Initial-Biofilm Formation on Titanium Surfaces.

BACKGROUND: Dental implants will be exposed to a complex ecosystem once they are placed in the oral cavity. The bacterial colonization and biofilm formation on these devices will depend not only on the physicochemical surface implant properties but also on the periodontal health conditions of the patients, as these devices are exposed. PURPOSE: The aim of this study was to correlate the subgingival microbial profile with the composition of initial biofilm formed on different microstructured titanium (Ti) surfaces. MATERIALS AND METHODS: Ten periodontitis and 10 periodontally healthy subjects were included in this study. The subjects wore a removable acrylic device with four different fixed Ti surfaces for 48 hours. Microbial samples of subgingival plaque and the biofilm formed on each Ti surface were individually analyzed by the checkerboard DNA-DNA hybridization technique. RESULTS: Despite the roughness or hydrophilicity of the Ti surfaces, a characteristic pattern of bacterial adhesion was observed on each of the study groups. However, significant differences in the proportion of the species that colonized the Ti surfaces were found between the periodontitis and periodontally healthy groups. Treponema denticola, Neisseria mucosa, Eikenella corrodens, and Tannerella forsythia were detected in higher proportions on the Ti disks placed in the periodontitis subjects, while significant higher proportions of Capnocytophaga sputigena, Fusobacterium periodonticum, Prevotella melaninogenica, and Streptococcus mitis were detected on the Ti disks placed in the periodontally healthy group. CONCLUSIONS: The results obtained in this study shows that the composition and the proportion of the species that initially colonize Ti surfaces are highly influenced by the periodontal status more than the surface characteristics of the Ti implant.