Purpose: This study investigated the magnitude, direction, and temporal aspects of the force applied during instrumentation with a piezoelectric ultrasonic periodontal scaler, compared this force with recommendations in the literature, and assessed the influence of the profession (dentist or dental hygienist) and calculus hardness. Materials and Methods: The force applied by ten dental hygienists and six dentists during debridement of comparatively soft and hard artificial dental calculus with a piezoelectric ultrasonic scaler was recorded in-vitro. The total force and its components in three axes were statistically analysed. Results: During debridement of soft artificial dental calculus, the mean total force applied by dental hygienists was 0.34 N (± 0.18 N, range: 0.13 N to 0.59 N) and by dentists 0.28 N (± 0.33 N, range: 0.06 N to 0.95 N), and the total force exceeded 0.5 N approximately 23% and 14% of the time for dental hygienists and dentists, respectively. During debridement of hard artificial dental calculus, the mean total force applied by dental hygienists was 0.63 N (± 0.40 N, range: 0.28 N to 1.64 N) and by dentists 0.57 N (± 0.17 N, range: 0.34 N to 0.76 N); the total force exceeded 0.5 N more than half of the time for both professions. On average, dental hygienists applied 1.85x (p = 0.04) and dentists 2.04x (p = 0.06) higher force on hard than on soft artificial calculus. However, dental hygienists and dentists used similar forces during the debridement of both hard (p = 1.00) and soft (p = 0.26) calculus. Conclusion: The force applied during the debridement of hard artificial dental calculus was statistically significantly higher than during the debridement of soft artificial dental calculus. No statistically significant difference between dentists and dental hygienists was found. The force applied by both groups on soft and hard artificial dental calculus frequently exceeded recommended values. Keywords: calculus, debridement, periodontal, piezoelectric, ultrasonic

Im Jahr 1928 beobachtete Alexander Flemming, dass in der Umgebung eines Schimmelpilzes (Kontamination einer Agarplatte) Staphylococcus-aureus-Bakterien nicht mehr wuchsen. Die vom Schimmelpilz produzierte Substanz mit antibakteriellen Eigenschaften wurde später Penicillin genannt. Die Ära der Antibiotika begann. Antibiotika (gegen das Leben) gehören wie die antiviralen Mittel und die Antimykotika zu den Antiinfektiva. Im Englischen wird auch oft die Bezeichnung „Antibacterials“ verwendet, vor allem in der deutschen Sprache wird von Antibiotika gesprochen.

Purpose: Antibiotics play an important role in treating periodontal diseases. Due to the effectiveness of antibiotic therapies, their usage in dentistry has significantly increased. The aim of this study focused on the in-vitro susceptibility of different gram-negative oral bacteria species – which are associated with periodontal diseases (Fusobacterium spp., Capnocytophaga spp. and Leptotrichia buccalis) and have different geographical origins (Asia and Europe) – against antimicrobials that are clinically relevant in dental therapy. Materials and Methods: A total of 45 strains were tested (29 Fusobacterium spp., 13 Capnocytophaga spp. and 3 L. buccalis) that were either isolated from Chinese patients or were obtained from different strain collections. Their antimicrobial susceptibility to the antimicrobial agents benzylpenicillin, amoxicillin, amoxicillin-clavulanic acid, ciprofloxacin, moxifloxacin, clindamycin, doxycycline, tetracycline and metronidazole was tested using the E-Test. Strains with particular resistance to penicillin, clindamycin and metronidazole were further analysed for resistance genes. Results: All tested bacterial isolates were sensitive to amoxicillin, amoxicillin-clavulanic acid, doxycycline and tetracycline, but showed variable sensitivity towards other antibiotics such as benzylpenicillin, ciprofloxacin, moxifloxacin, clindamycin and metronidazole. Conclusion: The results of the present study suggest that certain periodontal disease-related bacterial strains can be resistant towards antimicrobial agents commonly used in adjuvant periodontal therapy. Keywords: antibiotics, resistance, oral bacteria, clinical isolates, E-test

Purpose: To evaluate the effect of bovine milk and yogurt on selected oral microorganisms and different oral biofilms. Materials and Methods: Milk was prepared from 0.5% fat (low-fat) and 16% fat (high fat) milk powder. For yogurt preparation, the strains Lactobacillus delbrueckii ssp. bulgarcius and Streptococcus thermophilus were added to the milk. Minimal inhibitory concentrations (MIC) and minimal microbiocidal concentrations (MMC) of the test compounds were measured against various microorganisms by the microbroth dilution technique. Cariogenic periodontal biofilms and one containing Candida were created on plastic surfaces coated with test substances. Further, preformed biofilms were exposed to the test substances at a concentration of 100% for 10 min and thereafter 10% for 50 min. Both colony forming units (cfu) and metabolic activity were quantified in the biofilms. Results: Neither high-fat milk, low-fat milk nor casein inhibited the growth of any species. Yogurt and L. delbrueckii ssp. bulgaricus at low MIC and MMC suppressed the growth of Porphyromonas gingivalis and other bacteria associated with periodontal disease. High-fat yogurt decreased cfu in the forming periodontal biofilm by 90%. Both low- and high-fat yogurts reduced metabolic activity in newly forming and preformed periodontal and Candida biofilms, but not in the cariogenic biofilm. Conclusions: Yogurt and L. delbru eckii ssp. bulgaricus, but not milk, were bactericidal against periodontopathogenic bacteria. Yoghurt reduced the metabolic activity of a Candida biofilm and a periodontal biofilm. Yogurt and L. delbrueckii ssp. bulgaricus may have potential in prevention and therapy of periodontal diseases and Candida infections. Keywords: Candida, caries, milk products, oral bacteria, periodontitis

Purpose: To evaluate the use of hydrogen peroxide as an adjunct to ultrasonication (US) in biofilm removal and whether it can limit the spread of viable microorganisms in the aerosol. Materials and Methods: Multi-species biofilms were formed on dentin disks and titanium disks fixed on a plastic surface. After placing the specimens in a periodontal pocket model, an ultrasonic scaler was applied for 30 s, in part combined with 0.25% or 0.5% H2O2. After treatment, the remaining biofilm was analysed for bacterial counts (colony forming units [CFU]), biofilm quantity and metabolic activity. Further, the cytotoxic effect of hydrogen peroxide on periodontal ligament fibroblasts was assessed and the spread of bacteria in aerosol was quantified. Results: Ultrasonication reduced bacterial counts in biofilm, biofilm mass and metabolic activity on both dentin and titanium disks. Adjunctive use of 0.25% and 0.5% H2O2 more effectively reduced the viable bacteria in biofilm than ultrasonication alone; this was also found on both dentin and titanium. The different concentrations of H2O2 did not lead to corresponding differences in bacterial mass and metabolic activity. The spread of bacteria through aerosols was statistically significantly reduced when adjunctive H2O2 was used. However, a certain cytotoxic effect on periodontal ligament fibroblasts by H2O2 could not be ruled out. Conclusions: Irrigating with H2O2 during periodontal instrumentation with an ultrasonic scaler increases the reduction of viable bacteria within biofilms. It might limit bacterial spreading via aerosols. Keywords: aerosol, biofilm, hydrogen peroxide, periodontal therapy

Objectives: To verify the effect of adjunctive enamel matrix derivative (EMD) in subgingival reinstrumentation during supportive periodontal therapy. Method and materials: Using a split-mouth design, residual periodontal pockets with probing depth (PD) of 5 to 8 mm in 13 patients were treated by subgingival reinstrumentation with (test teeth) and without (control teeth) EMD. At baseline and after 6 and 12 months the clinical variables PD, clinical attachment level (CAL), and bleeding on probing (BOP) were recorded. At the same appointments gingival crevicular fluid (GCF) was collected to analyze for interleukin (IL)-1β, matrix metalloproteinase (MMP)-8, IL-10, and transforming growth factor (TGF)-β. Results: Statistically significant improvements in PD, CAL, and BOP occurred in both groups. The reduction of PD was significantly higher in the test group than in the control group after 12 months (P = .005). The change of IL-1β within 12 months was significantly different between both groups (P = .019). No other significant differences were detected between both groups. Conclusion: The study suggests that subgingival reinstrumentation with adjunctive EMD could additionally reduce probing pocket depth and the need for periodontal surgery. (Quintessence Int 2021;52:506–513; doi: 10.3290/j.qi.b1044079) Keywords: biomarkers, clinical variables, enamel matrix proteins, periodontitis, scaling and root planing

Purpose: To compare clinical outcomes and oral fluid biomarkers in gingivitis subjects using an electric toothbrush/irrigator combination (test) or a manual toothbrush alone (control) over 8 weeks. Materials and Methods: Subjects were randomly assigned to two groups of n = 30. In both groups, toothbrushing was performed twice daily at home and no additional interdental cleaning aids were allowed. Plaque Index (PLI), Gingival Index (GI), whole saliva (WS), and gingival crevicular fluid (GCF) samples were collected at weeks 2, 4, and 8. Results: Subjects’ mean age was 23 years and 52% were female. Overall baseline means were 1.31 for PLI, 1.07 for GI, and 34.9 for number of bleeding sites. At every follow-up visit, both groups differed statistically significantly (p < 0.001) from baseline for all clinical parameters. The test group demonstrated statistically significantly (p < 0.001) greater reductions in GI vs the control group by 18% at week 2, 17% at week 4 and 24% at week 8. The test group also demonstrated statistically significantly (p < 0.002) greater reductions in the number of bleeding sites vs the control group by 33% at week 2, 34% at week 4 and 43% at week 8. Between-group comparisons for both WS and GCF revealed numerical trends for decreased levels of interleukin (IL)-1β in GCF after 4 and 8 weeks, but these were not statistically significant. Conclusion: In subjects using the electric toothbrush/irrigator combination, increased clinical improvements may be found accompanied by similarly improved trends for oral fluid biomarkers such as IL-1β. Keywords: gingival crevicular fluid, gingivitis, prevention, toothbrushing

Purpose: The topical fluoride treatment of teeth can lead to a formation of CaF2-like material, which is considered to play a significant role in caries prevention. Different types of fluoride sources are applied. The aim of this study was to analyse the in vitro fluoridation effect of the lesser known organic fluoride compound nicomethanol hydrofluoride (NH) regarding fluoride accumulation and morphological changes on dental enamel surfaces. Materials and Methods: The fluoridation effect was investigated by scanning electron microscopy (SEM) and energy dispersive x-ray analysis (EDX) after treatment with fluoride solutions at a concentration of 1350 ppm F - and a pH value of 5.5. NH was tested against inorganic sodium fluoride (NaF) as reference. Fluoridation was done on pellicle-free and pellicle-covered enamel. Results: Formation of globular CaF2-like material was observed for both fluoride types. However, NH led to considerably higher calcium fluoride accumulation on the enamel surface as shown by both EDX and SEM. The globule diameters varied between 0.2 and 0.8 µm. Cross-sectional analysis revealed that the globular precipitates lay directly on the enamel surface; only the very surface-near volume was affected. No statistically significant difference of the fluoridation effect was measured with vs without saliva pre-treatment. Conclusion: The experiments showed a 6 times greater F - surface uptake on dental enamel with NH compared to sodium fluoride, thus suggesting an important role of NH during remineralization phases, fostering equilibrium between de- and remineralization. Keywords: amine fluorides, calcium fluoride precipitation, enamel, energy dispersive x-ray analysis, scanning electron microscopy

Purpose: Systemic inflammation is characteristic for the pathogenesis of Alzheimer’s disease (AD) and is responsible for the accumulation of its disease-specific Tau-protein and β-amyloid plaques. Studies focusing on an association with periodontitis showed worse periodontal conditions in patients with dementia, but until now, no study has investigated the differences between AD and other forms of dementia (noAD/DEM). Expecting severe periodontal disease in AD, the aim of this pilot-study was to compare the periodontal and dental status in patients with either AD or noAD/DEM. Materials and Methods: Twenty patients recently diagnosed with AD and 20 with noAD/DEM between the ages of 50 and 70 years were recruited at the Department of Neurology, University Hospital, Münster, Germany and clinically examined at the Department of Periodontology, School of Dental Medicine, Münster, Germany. Neuropsychological testing, levels of Tau-protein and β-amyloid in serum and liquor were used to distinguish between both groups. Dental and periodontal parameters such as clinical attachment loss (CAL), probing pocket depth (PPD), bleeding-on-probing (BOP), radiographic bone loss, full-mouth plaque score (FMPS), and missing and restored teeth were recorded. Results: Periodontitis was diagnosed in all patients. Patients with AD presented mean BOP of 54.7 ± 31.1% and radiographic bone loss of 42.5 ± 25.3%; the mean BOP of those with noAD/DEM was 52.0 ± 23.7% and radiographic bone loss was 40.9 ± 32.3%. There was also no statistically significant difference regarding other periodontal and dental parameters. Conclusions: Both patients with AD and noAD/DEM had periodontal disease. Consequently, patients with all forms of dementia (AD/other) need special dental care to improve periodontal and oral health. Keywords: Alzheimer’s disease, dementia, dental care, oral health, periodontal disease

Purpose: Grape-seed extract (GSE) contains polyphenols that readily adhere to proteins and modify the acquired enamel pellicle (AEP). The first step in biofilm formation is bacterial adhesion to the AEP-covered enamel. The aim of this in vitro study was to test whether AEP modification with GSE, fluoride (F-), or their combination (GSE+F-) modulates bacterial adhesion, biofilm metabolism and composition, or cariogenic demineralisation of the enamel. Materials and Methods: The study comprised 3 parts: 1) single-strain Streptococcus gordonii species, 2) a five-species biofilm model, or 3) biofilm (re-)formation using the five-species biofilm model after removal of initial biofilm with toothbrushing. Human whole-mouth stimulated saliva was used to form an AEP on human enamel specimens. The AEP was incubated in water (control), or modified with GSE, F-, or GSE+F-. Bacterial adhesion, biofilm diversity, metabolic activity, biofilm mass, and cariogenic demineralisation (surface hardness) of enamel were assessed after incubation in bacterial broths after 4 h or 22 h. Differences between groups were analysed with one-way ANOVA and post-hoc Bonferroni tests. Results: GSE and GSE+F- statistically significantly decreased single-strain S. gordonii adhesion, but had no relevant influence when the five-species biofilm model was used. In the biofilm (re-)formation model, GSE reduced bacterial adhesion compared to GSE+F-, while F- caused less cariogenic demineralisation than was found in the control group. Conclusion: AEP modified with GSE retards S. gordonii adhesion, but it does not influence the formation, metabolism and composition of a cariogenic multi-species biofilm. Keywords: biofilms, caries, dental pellicle, enamel, fluoride, grape-seed extract, pellicle modification