Thickness of softened human enamel removed by toothbrush abrasion: an in vitro study

The aim of the study was to assess the thickness of softened enamel removed by toothbrushing. Human enamel specimens were indented with a Knoop diamond. Softening was performed with citric acid or orange juice. The specimens were brushed in a brushing machine with a manual soft toothbrush in toothpaste slurry or in artificial saliva. Enamel loss was calculated from the change in indentation depth of the same indent before and after abrasion. Mean surface losses (95% confidence interval) were recorded in treatment groups (in nanometers): (1) citric acid, abrasion with slurry = 339 (280-398); (2) citric acid, abrasion with artificial saliva = 16 (5-27); (3) orange juice, abrasion with slurry = 268 (233-303); (4) orange juice, abrasion with artificial saliva = 14 (5-23); (5) no softening, abrasion with slurry = 28 (10-46). The calculated thickness of the softened enamel varied between 254 and 323 nm, depending on the acid used.

Clinical and antibacterial effect of an anti-inflammatory toothpaste formulation with Scutellaria baicalensis extract on experimental gingivitis

It was the aim of the study to evaluate the clinical and antibacterial effect of a dentifrice containing an anti-inflammatory plant extract (SB) versus a placebo (PLA) using an experimental gingivitis model. Forty subjects (20 per group) discontinued all oral hygiene measures for four teeth for a period of 21 days using a shield (to generate a possible gingivitis) while they could brush the other teeth normally. After brushing, the shield was removed and teeth were treated with the randomly assigned toothpaste slurry for 1 min. Löe and Silness gingival index (GI), Silness and Löe plaque index (PI), and biofilm vitality (VF%) were assessed at days 0, 14, and 21, respectively. Subjects of the PLA group developed a GI of 0.82?±?0.342 (day 14) and 1.585?±?0.218 (day 21), while the data of the SB group were significantly reduced (0.355?±?0.243 and 0.934?±?0.342, p?

Preventing erosion with novel agents

Objectives: This in vitro study aimed to investigate the protective effect of four commercial novel agents against erosion. Methods: Ninety human molars were distributed into 9 groups, and after incubation in human saliva for 2 h, a pellicle was formed. Subsequently, the specimens were submitted to demineralization (orange juice, pH 3.6, 3 min) and remineralization (paste slurry containing one of the tested novel agents, 3 min) cycles, two times per day, for 4 days. The tested agents were: (1) DenShield Tooth; active ingredient: 7.5% W/W NovaMin® (calcium sodium phosphosilicate); (2) Nanosensitive hca; active ingredient: 7.5% W/W NovaMin®; (3) GC Tooth Mousse; active ingredient: 10% Recaldent™ (CPP-ACP); (4) GC MI Paste Plus; active ingredients: 10% Recaldent™, 900 ppm fluoride. Two experimental procedures were performed: in procedure 1, the tested agents were applied prior to the erosive attack, and in procedure 2 after the erosive attack. A control group receiving no prophylactic treatment was included. Surface nanohardness (SNH) of enamel specimens was measured after pellicle formation and after completion of daily cyclic treatment. Results: SNH significantly decreased at the end of the experiment for all groups (p < 0.05). In both procedures, there was no statistically significant difference between the control group and those treated with paste slurries (p > 0.05). In addition, the changes in SNH (ΔSNH = SNHbaseline − SNHfinal) did not show statistically significant difference between both procedures (p > 0.05). Conclusion: Tooth erosion cannot be prevented or repaired by these novel agents, regardless of fluoride content.

Osteogenic potential of autogenous bone grafts harvested with four different surgical techniques

The osteogenic potential of autogenous bone grafts is superior to that of allografts and xenografts because of their ability to release osteoinductive growth factors and provide a natural osteoconductive surface for cell attachment and growth. In this in vitro study, autogenous bone particles were harvested by four commonly used techniques and compared for their ability to promote an osteogenic response. Primary osteoblasts were isolated and seeded on autogenous bone grafts prepared from the mandibles of miniature pigs with a bone mill, piezo-surgery, bone scraper, and bone drill (bone slurry). The osteoblast cultures were compared for their ability to promote cell attachment, proliferation, and differentiation. After 4 and 8 hrs, significantly higher cell numbers were associated with bone mill and bone scraper samples compared with those acquired by bone slurry and piezo-surgery. Similar patterns were consistently observed up to 5 days. Furthermore, osteoblasts seeded on bone mill and scraper samples expressed significantly elevated mRNA levels of collagen, osteocalcin, and osterix at 3 and 14 days and produced more mineralized tissue as assessed by alizarin red staining. These results suggest that the larger bone graft particles produced by bone mill and bone scraper techniques have a higher osteogenic potential than bone slurry and piezo-surgery.

Comparison of gingival crevicular fluid sampling methods in patients with severe chronic periodontitis

The analysis of samplings from periodontal pockets is important in the diagnosis and therapy of periodontitis. In this study, three different sampling techniques were compared to determine whether one method yielded samples suitable for the reproducible and simultaneous determination of bacterial load, cytokines, neutrophil elastase, and arginine-specific gingipains (Rgps). Rgps are an important virulence factor of Porphyromonas gingivalis, the exact concentration of which in gingival crevicular fluid (GCF) has not been quantified.

Impact of Bone Harvesting Techniques on Cell Viability and the Release of Growth Factors of Autografts

Background: Autogenous bone grafts obtained by different harvesting techniques behave differently during the process of graft consolidation; the underlying reasons are however not fully understood. One theory is that harvesting techniques have an impact on the number and activity of the transplanted cells which contribute to the process of graft consolidation. Materials and Methods: To test this assumption, porcine bone grafts were harvested with four different surgical procedures: bone mill, piezosurgery, bone drilling (bone slurry), and bone scraper. After determining cell viability, the release of molecules affecting bone formation and resorption was assessed by reverse transcription polymerase chain reaction and immunoassay. The mitogenic and osteogenic activity of the conditioned media was evaluated in a bioassay with isolated bone cells. Results: Cell viability and the release of molecules affecting bone formation were higher in samples harvested by bone mill and bone scraper when compared with samples prepared by bone drilling and piezosurgery. The harvesting procedure also affected gene expression, for example, bone mill and bone scraper samples revealed significantly higher expression of growth factors such as bone morphogenetic protein-2 and vascular endothelial growth factor compared with the two other modalities. Receptor activator of nuclear factor kappa B ligand expression was lowest in bone scraper samples. Conclusion: These data can provide a scientific basis to better understand the impact of harvesting techniques on the number and activity of transplanted cells, which might contribute to the therapeutic outcome of the augmentation procedure.

Conventional and anti-erosion fluoride toothpastes: effect on enamel erosion and erosion-abrasion

New toothpastes with anti-erosion claims are marketed, but little is known about their effectiveness. This study investigates these products in comparison with various conventional NaF toothpastes and tin-containing products with respect to their erosion protection/abrasion prevention properties. In experiment 1, samples were demineralised (10 days, 6 × 2 min/day; citric acid, pH 2.4), exposed to toothpaste slurries (2 × 2 min/day) and intermittently stored in a mineral salt solution. In experiment 2, samples were additionally brushed for 15 s during the slurry immersion time. Study products were 8 conventional NaF toothpastes (1,400-1,490 ppm F), 4 formulations with anti-erosion claims (2 F toothpastes: NaF + KNO(3) and NaF + hydroxyapatite; and 2 F-free toothpastes: zinc-carbonate-hydroxyapatite, and chitosan) and 2 Sn-containing products (toothpaste: 3,436 ppm Sn, 1,450 ppm F as SnF(2)/NaF; gel: 970 ppm F, 3,030 ppm Sn as SnF(2)). A mouth rinse (500 ppm F as AmF/NaF, 800 ppm Sn as SnCl(2)) was the positive control. Tissue loss was quantified profilometrically. In experiment 1, most NaF toothpastes and 1 F-free formulation reduced tissue loss significantly (between 19 and 42%); the Sn-containing formulations were the most effective (toothpaste and gel 55 and 78% reduction, respectively). In experiment 2, only 4 NaF toothpastes revealed significant effects compared to the F-free control (reduction between 29 and 37%); the F-free special preparations and the Sn toothpaste had no significant effect. The Sn gel (reduction 75%) revealed the best result. Conventional NaF toothpastes reduced the erosive tissue loss, but had limited efficacy regarding the prevention of brushing abrasion. The special formulations were not superior, or were even less effective.

Vertical transmission of a fluoroquinolone-resistant Escherichia coli within an integrated broiler operation

The epidemiology of an enrofloxacin-resistant Escherichia coli clone was investigated during two separate outbreaks of colibacillosis in the Danish broiler production. In total five flocks were reported affected by the outbreaks. Recorded first-week mortalities were in the range of 1.7-12.7%. The clone was first isolated from dead broilers and subsequently demonstrated in samples from associated hatchers and the parent flock with its embryonated eggs, suggesting a vertical transmission from the parents. The second outbreak involved two broiler flocks unrelated to the affected flocks from the first outbreak. However, the clone could not be demonstrated in the associated parent flock. Furthermore, samplings from grand-parent flocks were negative for the outbreak clone. The clonality was evaluated by plasmid profiling and pulsed-field gel electrophoresis. None of the recognized virulence factors were demonstrated in the outbreak clone by microarray and PCR assay. The molecular background for the fluoroquinolone-resistance was investigated and point mutations in gyrA and parC leading to amino-acid substitutions in quinolone-resistance determining regions of GyrA and ParC were demonstrated. Vertical transmission of enrofloxacin-resistant E. coli from healthy parents resulting in high first-week mortality in the offspring illustrates the potential of the emergence and spreading of fluoroquinolone-resistant bacteria in animal husbandry, even though the use of fluoroquinolones is restricted.

Impact of different toothpastes on the prevention of erosion

The aim of the present study was to test the impact of different toothpastes on the prevention of erosion. Enamel demineralization and remineralization were monitored using surface microhardness (SMH) measurements. Human enamel specimens were treated following two different procedures: (1) incubation in toothpaste slurry followed by acid softening and artificial saliva exposure; (2) acid softening followed by incubation in toothpaste slurry and artificial saliva exposure. For the control procedure, toothpaste treatment was excluded. The following toothpastes were tested: Zendium, Sensodyne Proschmelz (Pronamel), Prodent Rocket Power, Meridol and Signal active. Normalized SMH values compared to the baseline (= 1.00) after 1-hour artificial saliva exposure for procedure 1 (respectively for procedure 2) were as follows (mean: 95% CI): Sensodyne Proschmelz 0.97: 0.93, 1.00 (0.92: 0.90, 0.94), Zendium 0.97: 0.94, 1.00 (0.89: 0.83, 0.95), Meridol 0.97: 0.94, 1.00 (0.94: 0.92, 0.96), Signal active 0.94: 0.91, 0.97 (0.95: 0.91, 0.99), Prodent Rocket Power 0.92: 0.90, 0.94 (0.93: 0.89, 0.97) and control 0.91: 0.88, 0.94. Further exposure to artificial saliva for up to 4 h showed no significant improvement of SMH. Regression analyses revealed a significant impact of the applied procedure. Incubation in toothpaste slurries before the acid challenge seems to be favorable to prevent erosion. None of the tested toothpastes showed statistically significant better protection than another against an erosive attack.

Controlled toothbrush abrasion of softened human enamel

The aim of this in vitro study was to compare toothbrush abrasion of softened enamel after brushing with two (soft and hard) toothbrushes. One hundred and fifty-six human enamel specimens were indented with a Knoop diamond. Salivary pellicle was formed in vitro over a period of 3 h. Erosive lesions were produced by means of 1% citric acid. A force-measuring device allowed a controlled toothbrushing force of 1.5 N. The specimens were brushed either in toothpaste slurry or with toothpaste in artificial saliva for 15 s. Enamel loss was calculated from the change in indentation depth of the same indent before and after abrasion. Mean surface losses (95% CI) were recorded in ten treatment groups: (1) soft toothbrush only [28 (17-39) nm]; (2) hard toothbrush only [25 (16-34) nm]; (3) soft toothbrush in Sensodyne MultiCare slurry [46 (27-65) nm]; (4) hard toothbrush in Sensodyne MultiCare slurry [45 (24-66) nm]; (5) soft toothbrush in Colgate sensation white slurry [71 (55-87) nm]; (6) hard toothbrush in Colgate sensation white slurry [85 (60-110) nm]; (7) soft toothbrush with Sensodyne MultiCare [48 (39-57) nm]; (8) hard toothbrush with Sensodyne MultiCare [40 (29-51) nm]; (9) soft toothbrush with Colgate sensation white [51 (37-65) nm]; (10) hard toothbrush with Colgate sensation white [52 (36-68) nm]. Neither soft nor hard toothbrushes produced significantly different toothbrush abrasion of softened human enamel in this model (p > 0.05).

Two-year outcome with Nobel Direct implants: a retrospective radiographic and microbiologic study in 10 patients

INTRODUCTION: The Nobel Direct implant (Nobel Biocare AB, Göteborg, Sweden) was developed to minimize marginal bone resorption and to result in "soft tissue integration" for an optimized aesthetic outcome. However, conflicting results have been presented in the literature. The aim of this present study was to evaluate the clinical and microbiologic outcomes of Nobel Direct implants. MATERIALS AND METHODS: Ten partially edentulous subjects without evidence of active periodontitis (mean age 55 years) received 12 Nobel Direct implants. Implants were loaded with single crowns after a healing period of 3 to 6 months. Treatment outcomes were assessed at month 24. Routine clinical assessments, intraoral radiographs, and microbiologic samplings were made. Histologic analysis of one failing implant and chemical spectroscopy around three unused implants was performed. Paired Wilcoxon signed-rank test was used for the evaluation of bone loss; otherwise, descriptive analysis was performed. RESULTS: Implants were functionally loaded after 3 to 6 months. At 2 years, the mean bone loss of remaining implants was 2.0 mm (SD +/- 1.1 mm; range: 0.0-3.4 mm). Three out of 12 implants with an early mean bone loss >3 mm were lost. The surviving implants showed increasing bone loss between 6 and 24 months (p = .028). Only 3 out of the 12 implants were considered successful and showed bone loss of <1.7 mm after 2 years. High rates of pathogens, including Aggregatibacter actinomycetemcomitans, Fusobacterium spp., Porphyromonas gingivalis, Pseudomonas aeruginosa, and Tanerella forsythia, were found. Chemical spectroscopy revealed, despite the normal signals from Ti, O, and C, also peaks of P, F, S, N, and Ca. A normal histologic image of osseointegration was observed in the apical part of the retrieved implant. CONCLUSION: Radiographic evidence and 25% implant failures are indications of a low success rate. High counts and prevalence of significant pathogens were found at surviving implants. Although extensive bone loss had occurred in the coronal part, the apical portion of the implant showed some bone to implant integration.

Randomised in situ study on the efficacy of a tin/chitosan toothpaste on erosive-abrasive enamel loss

Tin is a notable anti-erosive agent, and the biopolymer chitosan has also shown demineralisation-inhibiting properties. Therefore, the anti-erosive/anti-abrasive efficacy of the combination of both compounds was tested under in situ conditions. Twenty-seven volunteers were included in a randomised, double-blind, three-cell crossover in situ trial. Enamel specimens were recessed on the buccal aspects of mandibular appliances, extraorally demineralised (6 × 2 min/day) and intraorally treated with toothpaste slurries (2 × 2 min/day). Within the slurry treatment time, one-half of the specimens received additional intraoral brushing (5 s, 2.5 N). The tested toothpastes included a placebo toothpaste, an experimental NaF toothpaste (1,400 ppm F(-)) and an experimental F/Sn/chitosan toothpaste (1,400 ppm F(-), 3,500 ppm Sn(2+), 0.5% chitosan). The percentage reduction of tissue loss (slurry exposure/slurry exposure + brushing) compared to placebo was 19.0 ± 47.3/21.3 ± 22.4 after use of NaF and 52.5 ± 30.9/50.2 ± 34.3 after use of F/Sn/chitosan. F/Sn/chitosan was significantly more effective than NaF (p ≤ 0.001) and showed good efficacy against erosive and erosive-abrasive tissue loss. This study suggests that the F/Sn/chitosan toothpaste could provide good protection for patients who frequently consume acidic foodstuffs.

Impact of bone graft harvesting techniques on bone formation and graft resorption: a histomorphometric study in the mandibles of minipigs.

BACKGROUND: Harvesting techniques can affect cellular parameters of autogenous bone grafts in vitro. Whether these differences translate to in vivo bone formation, however, remains unknown. OBJECTIVE: The purpose of this study was to assess the impact of different harvesting techniques on bone formation and graft resorption in vivo. MATERIAL AND METHODS: Four harvesting techniques were used: (i) corticocancellous blocks particulated by a bone mill; (ii) bone scraper; (iii) piezosurgery; and (iv) bone slurry collected from a filter device upon drilling. The grafts were placed into bone defects in the mandibles of 12 minipigs. The animals were sacrificed after 1, 2, 4 and 8 weeks of healing. Histology and histomorphometrical analyses were performed to assess bone formation and graft resorption. An explorative statistical analysis was performed. RESULTS: The amount of new bone increased, while the amount of residual bone decreased over time with all harvesting techniques. At all given time points, no significant advantage of any harvesting technique on bone formation was observed. The harvesting technique, however, affected bone formation and the amount of residual graft within the overall healing period. Friedman test revealed an impact of the harvesting technique on residual bone graft after 2 and 4 weeks. At the later time point, post hoc testing showed more newly formed bone in association with bone graft processed by bone mill than harvested by bone scraper and piezosurgery. CONCLUSIONS: Transplantation of autogenous bone particles harvested with four techniques in the present model resulted in moderate differences in terms of bone formation and graft resorption.

Chronic bovine besnoitiosis: intra-organ parasite distribution, parasite loads and parasite-associated lesions in subclinical cases.

Bovine besnoitiosis caused by Besnoitia besnoiti is a chronic and debilitating disease. The most characteristic clinical signs of chronic besnoitiosis are visible tissue cysts in the scleral conjunctiva and the vagina, thickened skin and a generally poor body condition. However, many seropositive animals remain subclinically infected, and the role that these animals may play in spreading the disease is not known. The aim of the present study was to assess the intra-organ parasite distribution, the parasite load and the parasite-associated lesions in seropositive but subclinically infected animals. These animals were seropositive at the time of several consecutive samplings, had visible tissue cysts in the past and, at time of slaughter, had detectable specific anti-Besnoitia spp. antibody levels, but they did not show evident clinical signs at culling. Thus, histopathological, immunohistochemical and molecular analyses of several samples from the respiratory tract, reproductive tract, other internal organs and skin from six cows were performed. The tissue cysts were located primarily in the upper respiratory tract, i.e., in the rhinarium and larynx/pharynx (four cows), followed by the distal genital tract (vulva/vagina) and the skin of the neck (three and two cows, respectively, out of the four cows with cysts in the respiratory tract). We were unable to detect any parasites in the two remaining cows. Cysts were associated with a significant non-purulent inflammatory infiltrate consisting predominantly of T lymphocytes and activated monocytes/macrophages in two cows. The parasite burden, estimated by quantitative real-time PCR, was very low. It is noteworthy that the only animal that showed a recent increase in the antibody titre had the highest parasite burden and the most conspicuous inflammatory reaction against the cysts. In conclusion, although these cows no longer displayed any visible signs of besnoitiosis, they remained infected. Therefore, cows without visible signs of disease may still be able to transmit the parasite.

Clinical outcomes and molecular genotyping of Staphylococcus aureus isolated from milk samples of dairy primiparous Mediterranean buffaloes (Bubalus bubalis)

Staphylococcus aureus is one of the most important pathogens causing mastitis in dairy cows and in Mediterranean buffaloes. Genotype B (GTB) is contagious in dairy cows and may occur in up to 87% of cows of a dairy herd. It was the aim of this study to evaluate genotypes present, clinical outcomes, and prevalence of Staph. aureus in milk samples of primiparous Mediterranean dairy buffaloes. Two hundred composite milk samples originating from 40 primiparous buffaloes were collected from May to June 2012, at d 10, 30, 60, 90, and 150 d in milk (DIM) to perform somatic cell counts and bacteriological cultures. Daily milk yields were recorded. Before parturition until 40 to 50 DIM, all primiparous animals were housed separated from the pluriparous animals. Milking was performed in the same milking parlor, but the primiparous animals were milked first. After 50 DIM, the primiparous were mixed with the pluriparous animals, including the milking procedure. Individual quarter samples were collected from each animal, and aliquots of 1 mL were mixed and used for molecular identification and genotyping of Staph. aureus. The identification of Staph. aureus was performed verifying the presence of nuc gene by nuc gene PCR. All the nuc-positive isolates were subjected to genotype analysis by means of PCR amplification of the 16S-23S rRNA intergenic spacer region and analyzed by a miniaturized electrophoresis system. Of all 200 composite samples, 41 (20.5%) were positive for Staph. aureus, and no genotype other than GTB was identified. The prevalence of samples positive for Staph. aureus was 0% at 10 DIM and increased to a maximum of 22/40 (55%) at 90 DIM. During the period of interest, 14 buffaloes tested positive for Staph. aureus once, 6 were positive twice, and 5 were positive 3 times, whereas 15 animals were negative at every sampling. At 90 and 150 DIM, 7 (17.5%) and 3 buffaloes (7.5%), respectively, showed clinical mastitis (CM), and only 1 (2.5%) showed CM at both samplings. At 60, 90, and 150 DIM, 1 buffalo was found with subclinical mastitis at each sampling. At 30, 60, 90, and 150 DIM, 2.5 (1/40), 22.5 (9/40), 35 (14/40), and 10% (4/40) were considered affected by intramammary infection, respectively. Buffaloes with CM caused by Staph. aureus had statistically significantly higher mean somatic cell count values (6.06 ± 0.29, Log10 cells/mL ± standard deviation) and statistically significantly lower mean daily milk yields (7.15 ± 1.49, liters/animal per day) than healthy animals (4.69 ± 0.23 and 13.87 ± 2.64, respectively), buffaloes with IMI (4.82 ± 0.23 and 11.16 ± 1.80, respectively), or with subclinical mastitis (5.47 ± 0.10 and 10.33 ± 0.68, respectively). Based on our knowledge, this is the first time that Staph. aureus GTB has been identified in milk samples of dairy Mediterranean buffaloes.