Three-dimensional analysis of initial biofilm formation on polytetrafluoroethylene in the oral cavity.

AIM: There is published evidence that polytetrafluoroethylene (PTFE) exhibits beneficial surface characteristics by means of long-term biofilm accumulation. The purpose of this study was to investigate and compare early biofilm formation on polytetrafluoroethylene, ceramic-reinforced polytetrafluoroethylene and as the control group, stainless steel. MATERIALS AND METHODS: This study comprised 10 healthy volunteers (5 females and 5 males) with a mean age of 27.3 ± 3.7 years. Three different slabs (two PTFE coatings: one pure and one ceramic-reinforced polytetrafluoroethylene, and stainless steel) were placed in random order on a splint in the mandibular molar region. Intraoral splints were inserted for 48 h. After 48 h, we removed the slabs from the splints and stained the biofilm with a two-color fluorescence assay for bacterial viability (LIVE/DEAD BacLight-Bacterial Viability Kit 7012, Invitrogen, Mount Waverley, Australia). The amount of biofilm accumulation was assessed using confocal laser scanning microscopy (CLSM). RESULTS: The biofilm surface coverage was 55.8 ± 39.8% on pure PTFE-coated probes, 55.9 ± 35.0% on ceramic-reinforced PTFE-coated probes, and 33.3 ± 37.8% on stainless steel. The differences among the three groups were not significant (p = 0.301). Biofilm depth was 5.6 ± 5.4 µm on pure PTFE-coated probes, 5.2 ± 3.8 µm on ceramic-reinforced PTFE-coated probes, and 2.4 ± 2.9 µm on stainless steel. The Friedman test revealed a significant difference in biofilm depth (p = 0.002). Pairwise comparison of biofilm accumulation yielded a significant difference between pure PTFE and ceramic-reinforced PTFE compared to stainless steel (p = 0.017; p = 0.005). CONCLUSION: Our results indicate that the beneficial surface characteristics of PTFE coatings by reducing long-term biofilm are not a result of inhibiting initial bacterial adhesion.

16S rDNA-based metagenomic analysis of human oral plaque microbiota in patients with atherosclerosis and healthy controls.

To address the question if an altered oral microbiota is associated with atherosclerosis. Twenty patients suffering from atherosclerosis and 10 controls were recruited. Clinical oral, medical and laboratory investigations were performed. Oral bacteria were collected and 16S rDNA was sequenced following Single strand conformation polymorphism.(SSCP) Probing pocket depths in patients were significantly elevated. The oral microbiota of patients and controls were dominated by Fusobacterium (16%/17%), Streptococcus (21%/14%), Prevotella (10%/12%), Enterococcus (12%/12%), Porphyromonas (8%/7%), TM7 (0%/7%) and Veillonella (6%/7%). Differences in diversity were not significant between groups. The pathology of atherosclerosis may not be related to significant qualitative changes of the oral microbiota.

Microbial diversity of supra- and subgingival biofilms on freshly colonized titanium implant abutments in the human mouth.

Supra- and subgingival biofilm formation is considered to be mainly responsible for early implant failure caused by inflammations of periimplant tissues. Nevertheless, little is known about the complex microbial diversity and interindividual similarities around dental implants. An atraumatic assessment was made of the diversity of microbial communities around titanium implants by single strand conformation polymorphism (SSCP) analysis of the 16S rRNA gene amplicons as well as subsequent sequence analysis. Samples of adherent supra- and subgingival periimplant biofilms were collected from ten patients. Additionally, samples of sulcusfluid were taken at titanium implant abutments and remaining teeth. The bacteria in the samples were characterized by SSCP and sequence analysis. A high diversity of bacteria varying between patients and within one patient at different locations was found. Bacteria characteristic for sulcusfluid and supra- and subgingival biofilm communities were identified. Sulcusfluid of the abutments showed higher abundance of Streptococcus species than from residual teeth. Prevotella and Rothia species frequently reported from the oral cavity were not detected at the abutments suggesting a role as late colonizers. Different niches in the human mouth are characterized by specific groups of bacteria. Implant abutments are a very valuable approach to study dental biofilm development in vivo.

The Effectiveness of Poly-(4-vinyl-N-hexylpyridiniumbromide) as an Antibacterial Implant Coating: An In Vitro Study.

The clinical success of osseointegrated dental implants depends on the strong attachment of the surrounding hard and soft tissues. Bacterial adhesion on implant surfaces can cause inflammatory reactions and may influence healing and long-term success of dental implants. Promising implant coatings should minimize bacterial adhesion, but allow epithelial and connective tissue attachment. Therefore, the present study has examined the bioactive effect of poly-(4-vinyl-N-hexylpyridiniumbromide) regarding typical oral bacteria as well as cytotoxicitiy to human cells considering different methods of connecting polymers to silicate-containing surfaces. The results revealed that the application of putative antibacterial and biocompatible polymer in coating strategies is affected by a variety of parameters. Published findings regarding reduced bacterial adhesion could not be verified using oral pathogens whereas hexylated polymers seem problematic for strong adhesion of soft tissue. Concerning innovative coatings for dental implants basic aspects (surface roughness, thickness, alkylation, combination with other polymers) have to be considered in further investigations.

Reduction of biofilm on orthodontic brackets with the use of a polytetrafluoroethylene coating.

SUMMARY: Treatment with fixed orthodontic appliances can cause enamel demineralization by increased biofilm adhesion. The purpose of the present study was to investigate whether a polytetrafluoroethylene (PTFE) coating reduces biofilm formation on orthodontic brackets. One PTFE-coated bracket and one uncoated stainless steel bracket were bonded symmetrically on the first or second (four maxillary and nine mandibular) primary molars in 13 adolescent patients (five females and eight males, aged 11.2 +/- 2.8 years; four dropouts) for 8 weeks. Quantitative biofilm formation on brackets was analysed with the Rutherford backscattering detection (RBSD) method, a scanning electron microscopy technique. A total of five RBSD micrographs were obtained per bracket with views from the buccal, mesial, distal, cervical, and occlusal aspects. A two-sided paired t-test was used to compare data. A P-value less than 0.05 was considered significant. Total biofilm formation was 4.0 +/- 3.6 per cent of the surface on the PTFE-coated brackets and 22.2 +/- 5.4 per cent on uncoated brackets. Differences between the two groups were statistically significant (P < 0.05). Pairwise comparison of biofilm formation with respect to location (buccal, mesial, distal, cervical, and occlusal) revealed a significantly lower biofilm accumulation on PTFE-coated brackets on all surfaces. The results indicate that PTFE coating of brackets reduces biofilm adhesion to a minimum and might have the potential to reduce iatrogenic side effects, e.g. decalcification during orthodontic treatment with fixed appliances.

Short-term influence of lingual orthodontic therapy on microbial parameters and periodontal status. A preliminary study.

OBJECTIVE: To perform a preliminary study of the short-term effect of fixed, customized lingual orthodontic appliances on periodontal and microbial parameters. MATERIALS AND METHODS: The sample comprised 20 subjects (6 males and 14 females) with a mean age of 22.3 years +/- 8.6 years. Before (T(0)) and 4 weeks after placement (T(1)) of custom-made lingual appliances on the lower teeth only, plaque index (PI), probing pocket depth (PPD), and bleeding on probing (BOP) were measured. A 16S rRNA-based polymerase chain reaction (PCR) method was used to detect Aggregatibacter actinomycetemcomitans ( Aa ) and Porphyromonas gingivalis ( Pg ) in the crevicular fluid. To compare periodontal parameters on bonded lingual (testing) and unbonded palatal (control) and labial (control) sites between T(0) and T(1), the Wilcoxon test was applied. RESULTS: On the lingual aspects of bonded teeth, a significant increase of BOP (T(0): 23.4 +/- 22.5%; T(1): 46.2 +/- 23.5%; P = .001) and PI (T(0): 0.3 +/- 0.3; T(1): 1.0 +/- 0.7; P = .001) was observed, but no significant changes for PPD (T(0): 2.1 +/- 0.4 mm; T(1): 2.2 +/- 0.3 mm; P = .286) were found. On control sites, no significant changes were recorded for any periodontal parameter. Aa was found in 25% of the patients at baseline (5 subjects) and in 35% of the patients at T(1) (2 additional positive subjects), whereas Pg was found in 5% of the cohort at T(0) and at T(1) (same patient). CONCLUSIONS: Even in the short term, insertion of fixed lingual appliances induced a worsening of periodontal parameters restricted to bonded lingual sites.

Influence of lingual orthodontic therapy on microbial parameters and periodontal status in adults.

Insertion of fixed orthodontic appliances can induce an increase in oral biofilm and thereby cause inflammation of the periodontal tissues. The purpose of this study was to perform a longitudinal analysis of clinical and microbial parameters after insertion of lingual brackets. Bleeding on probing (BOP), plaque index (PI), and pocket probing depth (PPD) were measured in 10 adults (8 females and 2 males, aged 29.0 +/- 4.7 years) who received treatment with custom-made lingual appliances (Incognito/iBraces) before (T0) and 3 months after beginning of treatment (T1). No supportive dental prophylaxis was undertaken. In addition, a 16S rRNA-based polymerase chain reaction (PCR) method was used to detect Aggregatibacter actinomycetemcomitans (Aa) and Porphyromonas gingivalis (Pg) in the crevicular fluid. A Wilcoxon test was used to compare clinical parameters at the buccal (control) and lingual sites between T0 and T1. At T0, BOP was 12.4 +/- 8.2 per cent, PPD 2.1 +/- 0.3 mm, and PI 0.1 +/- 0.2 at the buccal sites and at T1 14.3 +/- 8.1 per cent, 2.1 +/- 0.2 mm and 0.1 +/- 0.2, respectively. At the lingual sites, BOP was 22.2 +/- 19.0 per cent, PPD 2.3 +/- 0.3 mm, and PI 0.1 +/- 0.2 at T0 and at T1 56.2 +/- 31.6 per cent, 2.9 +/- 0.3 mm, and 1.2 +/- 1.1, respectively. Differences between T0 and T1 were significant for clinical parameters only at the lingual sites. Aa was found in five patients at baseline and in four at T1, whereas Pg was found in one patient at T0 and in two at T1. Insertion of fixed lingual appliances without supportive dental prophylaxis induced a worsening of clinical parameters restricted to the lingual sites, whereas the relative prevalence of Aa and Pg remained unchanged.

Analysis of supra- and subgingival long-term biofilm formation on orthodontic bands.

Insertion of fixed orthodontic appliances induces increased biofilm formation caused by a higher number of plaque-retentive sites. The purpose of the study was to perform a quantitative analysis of supra- and subgingival long-term biofilm formation on orthodontic bands. Ten patients (five females and five males, aged 18.3+/-5.4 years) who had received therapy with fixed orthodontic appliances for 24+/-9 months were enrolled in the study. Biofilm formation on 28 orthodontic bands was analyzed quantitatively with the Rutherford backscattering detection method, a scanning electron microscopy technique. The biofilm formation for the supra- and subgingival surfaces was calculated from the grey values. Statistical analysis was performed with a mixed model with the patient as the random factor. A P-value <0.05 was considered significant. A biofilm was found on 16.1+/-9.2 per cent of supragingival surfaces and on 3.6+/-4.4 per cent of subgingival surfaces. Differences in biofilm formation in supra- and subgingival surfaces were statistically significant (P<0.05) and formed a distinct demarcation line. Despite the presence of supragingival biofilm, no mature subgingival biofilm was found on the tested orthodontic bands.

Analysis of early biofilm formation on oral implants in man.

Biofilm formation on oral implants can cause inflammation of peri-implant tissues, which endangers the long-term success of osseointegrated implants. It has been reported previously that implants revealing signs of peri-implantitis contain subgingival microbiota similar to those of natural teeth with periodontitis. The purpose of the first part of this study was an atraumatic, quantitative investigation of biofilm formation on oral implant abutments; the objective of the second part was to investigate whether Haemophilus actinomycetemcomitans and Porphyromonas gingivalis were present in the crevicular fluid around oral implants. Biofilm formation on 14 healing abutments, inserted for 14 days in 10 patients, was analysed quantitatively by use of secondary-electron and Rutherford-backscattering-detection methods. A 16S rRNA-based polymerase chain reaction detection method was used to detect the presence of H. actinomycetemcomitans and P. gingivalis in the crevicular fluid. For this investigation, samples of sulcus fluid were collected with sterile paper points at four measurement points per abutment. The difference between biofilm coverage of supragingival surfaces (17.5 +/- 18.3%) and subgingival surfaces (0.8 +/- 1.0%) was statistically significant (P < 0.05). By use of universal primers, bacteria were found in all the samples taken, although the two periodontal pathogens were not found in any of the samples. The absence of periodontal pathogens from the sulcus fluid during initial bacterial colonization, despite massive supragingival biofilm formation, substantiates the assumption that cellular adherence of peri-implant tissue by means of hemidesmosoma, actin filaments and microvilli reduces the risk of formation of anaerobic subgingival pockets.