Wieland Heuer

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.

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.

Comparative analysis of long-term biofilm formation on metal and ceramic brackets.

OBJECTIVE To test the null hypothesis that stainless steel and ceramic brackets show no differences in biofilm adhesion. MATERIALS AND METHODS Twenty adolescents (6 boys, 14 girls) who had received fixed orthodontic therapy for 18.9 ± 3.2 months were divided into a metal and a ceramic bracket group. Thirty brackets per group were taken from central incisors, canines, and second premolars and quantitatively analyzed for biofilm coverage with the Rutherford backscattering detection method. Five micrographs were obtained per bracket with views from the buccal, mesial, distal, gingival, and occlusal aspects, resulting in a total of 300 images. Biofilm formation between groups was compared using the Mann-Whitney U-test (α = .05). RESULTS Total biofilm formation was 12.5% ± 5.7% (3.3 ± 1.6 mm(2)) of the surface on metal and 5.6% ± 2.4% (1.5 ± 0.6 mm(2)) on ceramic brackets. Differences between groups were statistically significant (P < .05). A pairwise comparison of biofilm formation revealed significantly lower biofilm formation on ceramic brackets with respect to intraoral location (central incisor, canine, second premolar) and bracket surface (buccal, mesial, distal). CONCLUSIONS The hypothesis was rejected. The results indicate that ceramic brackets exhibit less long-term biofilm accumulation than metal brackets.

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.

Composition of Microbial Oral Biofilms during Maturation in Young Healthy Adults

In the present study we aimed to analyze the bacterial community structure of oral biofilms at different maturation stages in young healthy adults. Oral biofilms established on membrane filters were collected from 32 human subjects after 5 different maturation intervals (1, 3, 5, 9 and 14 days) and the respective phylogenetic diversity was analyzed by 16S rDNA amplicon sequencing. Our analyses revealed highly diverse entire colonization profiles, spread into 8 phyla/candidate divisions and in 15 different bacterial classes. A large inter-individual difference in the subjects’ microbiota was observed, comprising 35% of the total variance, but lacking conspicuous general temporal trends in both alpha and beta diversity. We further obtained strong evidence that subjects can be categorized into three clusters based on three differently occurring and mutually exclusive species clusters.

Experimental Gingivitis Induces Systemic Inflammatory Markers in Young Healthy Individuals: A Single-Subject Interventional Study

Objectives We here investigated whether experimental gingivitis enhances systemic markers of inflammation which are also known as surrogate markers of atherosclerotic plaque development. Background Gingivitis is a low-level oral infection induced by bacterial deposits with a high prevalence within Western populations. A potential link between the more severe oral disease periodontitis and cardiovascular disease has already been shown. Methods 37 non-smoking young volunteers with no inflammatory disease or any cardiovascular risk factors participated in this single-subject interventional study with an intra-individual control. Intentionally experimental oral inflammation was induced by the interruption of oral hygiene for 21 days, followed by a 21-days resolving phase after reinitiation of oral hygiene. Primary outcome measures at baseline, day 21 and 42 were concentrations of hsCRP, IL-6, and MCP-1, as well as adhesion capacity and oxLDL uptake of isolated blood monocytes. Results The partial cessation of oral hygiene procedures was followed by the significant increase of gingival bleeding (34.0%, P<0.0001). This local inflammation was associated with a systemic increase in hsCRP (0.24 mg/L, P = 0.038), IL-6 (12.52 ng/L, P = 0.0002) and MCP-1 (9.10 ng/l, P = 0.124) in peripheral blood samples between baseline and day 21, which decreased at day 42. Monocytes showed an enhanced adherence to endothelial cells and increased foam cell formation after oxLDL uptake (P<0.050) at day 21 of gingivitis. Conclusions Bacterial-induced gingival low-level inflammation induced a systemic increase in inflammatory markers. Dental hygiene almost completely reversed this experimental inflammatory process, suggesting that appropriate dental prophylaxis may also limit systemic markers of inflammation in subjects with natural gingivitis. International Clinical Trials Register Platform of the World Health Organization, registry number: DRKS00003366, URL: http://apps.who.int/trialsearch/Default.aspx

Prevention of Early Vascular Graft Infection Using Regional Antibiotic Release

BACKGROUND Infections after prosthetic replacement of the aorta remain a serious and life-threatening complication. The only appropriate treatment is the surgical removal of the infected prosthesis. Accordingly, there is a need for new procedures to prevent the infection of vascular prostheses. This in vitro experiment investigated the effect of the pretreatment of vascular prostheses with antibiotics (daptomycin or baneocin) and the effect of antibiotics combined with fibrin sealant as possible prophylaxis of perioperative graft infection. METHODS Untreated prostheses served as controls. Pretreated prostheses of double woven velour vascular grafts were contaminated with Staphylococcus epidermidis, and colony-forming units were counted each day (CFU/mL). RESULTS The period of sterility differed significantly as a function of the pretreatment. Uncoated prostheses were immediately non-sterile and exhibited 2.63 ± 0.61 × 10(5) CFU/mL. Baneocin pretreatment resulted in sterility for 1.7 ± 0.6 (95% confidence interval (CI) 1.0-2.4) d before we detected 2.14 ± 0.57 × 10(5) CFU/mL on the prostheses. Pretreatment with daptomycin yielded 2.9 ± 0.4 (CI 2.6-3.2) and fibrin sealant/baneocin compound yielded 3.1 ± 0.3 (CI 2.9-3.3) d of sterility, after which 1.81 ± 0.86 × 10(5) CFU/mL and 1.04 ± 0.77 × 10(5) CFU/mL were recorded. Finally, pretreatment with fibrin sealant/daptomycin led to sterility for 7.1 ± 0.3 (CI 6.9-7.3) d, after which 0.77 ± 0.60 × 10(5) CFU/mL were observed on the prostheses. CONCLUSIONS The risk of vascular graft infection is reduced by pretreating the prostheses with antibiotics. The antibiotic/fibrin compound exhibited an effect of delayed antibiotic release. Vascular prostheses should therefore be pretreated with antibiotic solution to reduce bacterial adhesion. This procedure might be an effective prophylaxis for perioperative vascular graft infection and provides suitable protection for the prosthetic material.

Economic implications of infections of implantable cardiac devices in a single institution.

INTRODUCTION The use of medical devices, such as cardiac pacemakers, prosthetic heart valves and vascular prostheses, has become a routine treatment procedure in cardiovascular medicine. Unfortunately, bacterial infections of these devices are a serious and sometimes life-threatening for the patient, necessitating explantation. Despite implementing different prophylactic strategies to avoid contamination of the device, infections do occur. This study analysed the additional hospital costs associated with managing cardiac device infections, with special focus on cardiac pacemakers/defibrillators, prosthetic heart valves and vascular prostheses. METHODS Out of more than 2000 operations performed in our institution in 2006, we had 462 implantations/replacements of cardiac pacemakers/implantable cardioverter defibrillators (ICDs), 577 valve replacement procedures and 613 vascular operations. Among these, we analysed all patients who received operations because of an infection of their cardiac or vascular device. Our investigations focussed on standard parameters regarding additional hospital costs, including length of stay in hospital, required time in the operating room and time in the intensive care unit. RESULTS In 2006, we had nine cases (n=9) of prosthetic valve endocarditis in our hospital. The average length of stay in hospital for these patients was 25 days, resulting in euro72096 of additional hospital costs per case. Infection of vascular prostheses (n=6) leads to euro35506 per case and 28 days in the hospital. If an infection of cardiac pacemakers (n=7) does occur, the therapy causes a mean additional hospital cost of euro7091. CONCLUSION Cardiac device infections are serious and sometimes life-threatening. Therapy and eradication are difficult and protracted and cause high additional hospital costs. Based on our statistical data and the mean incidence of cardiac device infections, we presume for Germany between euro38 and euro140 million in additional hospital costs per year are incurred by infections of implantable cardiovascular devices. Active surveillance and establishment of a central register with documentation of every implantation and the occurrence of any infection can only realise detailed estimates of the economic damage caused by infection of cardiovascular implants. In consideration of the economic consequences, successful strategies must be developed to reduce the incidence of infections.

Introducing a Semi-Coated Model to Investigate Antibacterial Effects of Biocompatible Polymers on Titanium Surfaces

Peri-implant infections from bacterial biofilms on artificial surfaces are a common threat to all medical implants. They are a handicap for the patient and can lead to implant failure or even life-threatening complications. New implant surfaces have to be developed to reduce biofilm formation and to improve the long-term prognosis of medical implants. The aim of this study was (1) to develop a new method to test the antibacterial efficacy of implant surfaces by direct surface contact and (2) to elucidate whether an innovative antimicrobial copolymer coating of 4-vinyl-N-hexylpyridinium bromide and dimethyl(2-methacryloyloxyethyl) phosphonate (VP:DMMEP 30:70) on titanium is able to reduce the attachment of bacteria prevalent in peri-implant infections. With a new in vitro model with semi-coated titanium discs, we were able to show a dramatic reduction in the adhesion of various pathogenic bacteria (Streptococcus sanguinis, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis), completely independently of effects caused by soluble materials. In contrast, soft tissue cells (human gingival or dermis fibroblasts) were less affected by the same coating, despite a moderate reduction in initial adhesion of gingival fibroblasts. These data confirm the hypothesis that VP:DMMEP 30:70 is a promising antibacterial copolymer that may be of use in several clinical applications.