Assessing the hierarchical structure of titanium implant surfaces.

The physical texture of implant surfaces are known to be one important factor in creating a stable bone-implant interface. Simple roughness parameters (for e.g., Sa or Sz) are not entirely adequate when characterizing surfaces possessing hierarchical structure (macro, micro, and nano scales). The aim of this study was to develop an analytical approach to quantify hierarchical surface structure of implant surfaces possessing nearly identical simple roughness. Titanium alloys with macro/micro texture (MM) and macro/micro/nano texture (MMN) were chosen as model surfaces to be evaluated. There was no statistical difference (p > 0.05) in either Sa (13.56 vs. 13.43 µm) or Sz (91.74 vs. 92.39 µm) for the MM and MMN surfaces, respectively. However, when advanced filtering algorithms were applied to these datasets, a statistical difference in roughness was found between MM (Sa = 0.54 µm) and MMN (Sa = 1.06 µm; p < 0.05). Additionally, a method was developed to specifically quantify the density of surface features appearing similar in geometry to natural osteoclastic pits. This analysis revealed a significantly greater numbers of these features (i.e., valleys) on the MMN surface as compared to the MM surface. Finally, atomic force microscopy showed a rougher nano-texture on the MMN surface compared with the MM surface (p < 0.05). The results support recent published studies that show a combination of appropriate micron and nano surface results in a more robust cellular response and increased osteoblast differentiation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1083-1090, 2016.

NovaMin and dentin hypersensitivity--in vitro evidence of efficacy.

OBJECTIVE: The objective of this study was to determine the ability of a calcium sodium phosphosilicate (NovaMin) particulate to occlude dentin tubules, and to characterize the nature of the occlusion through a number of in vitro studies. METHODS: Four experiments were designed to demonstrate the ability of NovaMin to 1) rapidly occlude tubules, 2) remain on the dentin surface in the face of acid challenges, and 3) form a biologically stable hydroxycarbonate apatite layer on the surface of dentin. Bovine dentin samples, polished to 1200 grit silicon and etched in 40% w/w o-phosphoric acid solution for 15 minutes to remove the smear layer, were employed in all four experiments. Four different experimental techniques were used to evaluate the effects of NovaMin and other marketed calcium-based products on tubule occlusion in 1) a single-treatment model, 2) a 10-day acid challenge cycling model to evaluate tubule occlusion, 3) a 10-day acid challenge cycling model to evaluate changes in surface hardness, and 4) a calcium-release model. Samples were assessed for tubule occlusion by scanning electron microscopy, surface mineralization by microhardness, and calcium release by inductively coupled mass spectroscopy. RESULTS: For the single-treatment model, statistical analysis showed that all treatment groups had statistically fewer open tubules than the control group (untreated; p < 0.001), and that the NovaMin group occluded significantly more tubules than the Quell group (p < 0.001). For the cycling models, after a one-time brushing with the NovaMin (SootheRx) dentifrice, significantly fewer open tubules were visible compared to the untreated control (p < 0.001). After the 10-day cycle, there were few visible open tubules on the samples treated with SootheRx, a significant reduction when compared to the control samples (p < 0.001). The hardness of dentin treated with NovaMin during the 10-day cycle was significantly greater than sound and demineralized dentin (p < 0.001). The calcium-release model demonstrated NovaMin-based dentifrices released less calcium initially compared to the other treatment groups. After four hours, a higher release of calcium was observed that was sustained over 24 hours. CONCLUSION: NovaMin adheres to an exposed dentin surface and reacts with it to form a mineralized layer. The layer formed is resistant to acid challenges and is mechanically strong. The continuous release of calcium over time is suggested to maintain the protective effects on dentin, and provide continual occlusion of the dentin tubules.

The role of ionic release from NovaMin (calcium sodium phosphosilicate) in tubule occlusion: an exploratory in vitro study using radio-labeled isotopes.

OBJECTIVE: The primary objective of this work was to develop a method of quantifying the levels and source of calcium and phosphate deposited on dental hard tissue from a novel calcium phosphosilicate (NovaMin) material using neutron activation analysis (NAA). A second objective was to explore the utility of radiotracing to determine dentin porosity following exposure to calcium phosphosilicate. METHODS: Neutron activation was used to create isotopes of Ca and P in the calcium phosphosilicate particles. Gamma radiation emitted from these isotopes was used to identify and measure their uptake (concentration) onto dental hard tissue. Three experiments were conducted to explore calcium and phosphate uptake to dental hard tissue: 1) a dose response to quantify the relative levels of calcium and phosphate deposited on dental hard tissue as a function of calcium phosphosilicate dose; 2) the effect of calcium phosphosilicate particle size on the relative levels of calcium and phosphate uptake; and 3) the permeability of calcium phosphosilicate-treated dentin by employing the radiotracer technetium. For all experiments, extracted bovine incisors were employed as the test substrate. RESULTS: The results indicate there is a strong dose relationship between the wt% and particle size of calcium phosphosilicate in the dentifrice formulation and new Ca and P deposition. At above 5.0 wt% calcium phosphosilicate, there appears to be an exponential increase in the number of counts from the tooth surface. Finer particle size calcium phosphosilicate appears to deposit much higher levels of Ca and P than the larger range of particle sizes. The results from the technetium study show that when treated with the dentifrice slurry containing calcium phosphosilicate, dentin shows only a slight amount of technetium infiltration, indicating a lowering of dentin permeability. CONCLUSION: This exploratory study has demonstrated that NAA and the use of radio isotopes have utility in monitoring the uptake of Ca and P into both dentin and enamel tooth structure. The data generated from these studies have shown that there is a dose dependence and particle size effect for calcium phosphosilicate on the deposition of calcium and phosphate to dental hard tissue.

A clinical study of the effect of calcium sodium phosphosilicate on dentin hypersensitivity--proof of principle.

OBJECTIVE: NovaMin is technically described as amorphous sodium calcium phosphosilicate, and has been shown in laboratory studies to rapidly occlude dentin tubules through the deposition of particles that react to form a protective layer, similar to bone mineral, on the dentin surface. NovaMin was originally developed as a bone regenerative material and is highly biocompatible. The objective of this pilot study was to compare the safety and effectiveness of two prototype formulations containing 2.5% and 7.5% w/w NovaMin to a placebo dentifrice for the treatment of dentin hypersensitivity. METHODS: This was a randomized, double-blind, placebo-controlled pilot study. Sixty-six subjects with a confirmed diagnosis of dentin hypersensitivity were randomized to one of three treatments: 2.5% NovaMin, 7.5% NovaMin, or placebo. Two standard test stimuli, tactile and thermal air, were applied to sensitive cervical dentin surfaces. Subjects recorded the intensity of sensitivity in response to each stimulus on a visual analog scale at baseline, and after two, four, and eight weeks of twice-daily product use. Oral soft tissues were examined and spontaneous reports of adverse experiences were also monitored. RESULTS: Comparison of the mean change from baseline among the three treatment groups indicated a meaningful reduction in sensitivity scores in the 7.5% group that was significant compared to reductions observed in the placebo control group at all time points. CONCLUSION: The results of this study are supportive of the incorporation of NovaMin into products intended for the reduction of dentin hypersensitivity.

A clinical study comparing oral formulations containing 7.5% calcium sodium phosphosilicate (NovaMin), 5% potassium nitrate, and 0.4% stannous fluoride for the management of dentin hypersensitivity.

UNLABELLED: To determine and compare the clinical performance of formulations containing 7.5% calcium sodium phosphosilicate (NovaMin), 5% potassium nitrate, and 0.4% stannous fluoride for the management of dentin hypersensitivity. METHODS: This was a single-center, randomized, double-blind, parallel-group design with a duration of 12 weeks. The study included a total of 120 subjects and measured sensitivity to cold water and air blast by the use of a visual analogue scale. Measurements were taken at baseline, two, four, and 12 weeks. RESULTS: All three products significantly reduced sensitivity versus baseline at each time point, although the calcium sodium phosphosilicate (NovaMin) dentifrice reduced sensitivity significantly more than the others at the two- and four-week time points. At the two-week time point, for air and water, respectively, the dentifrice containing NovaMin reduced sensitivity 45% and 49%, the stannous fluoride gel 30% and 26%, and the potassium nitrate dentifrice 35% and 34%. At the 12-week time point, the dentifrice containing NovaMin reduced sensitivity 87% and 91%, stannous fluoride gel 87% and 85%, and potassium nitrate dentifrice 84% and 79%. CONCLUSION: In this study, all three products were effective. Compared to the potassium nitrate and stannous fluoride formulations, the dentifrice containing NovaMin provided more substantial and significant improvements at the early time points.

Clinical evaluation of a dentifrice containing calcium sodium phosphosilicate (novamin) for the treatment of dentin hypersensitivity.

PURPOSE: To evaluate the efficacy of a dentifrice containing calcium sodium phosphosilicate (NovaMin) study versus a placebo and a commercially-available SrCl2 containing dentifrice for the treatment of dentin hypersensitivity. METHODS: This was a 6-week, randomized, parallel-arm, double-blind clinical study. 71 subjects ranging in age from 21 to 56 years old completed the study. Evaporative and thermal stimuli were used to measure pain using a VAS scale. Measurements were obtained at baseline, 2 weeks and 6 weeks. RESULTS: The placebo and the NovaMin groups showed a statistically significant decrease in sensitivity by both measures after 6 weeks (P < 0.05). The SrCl2 group showed a statistically significant decrease from baseline at the 2-week time point, but not at the 6-week time point for the evaporative stimulus. The percent reduction in sensitivity at 6 weeks for the NovaMin test group was 35% for air and 39% for cold water stimulus, versus 11% for air and 22% for cold water for the SrCl2 paste. The reductions for the placebo paste were 21% for the air stimulus and 18% for water. A cross tabulation measure of the reduction in sensitivity at each time point for all three treatments showed that the NovaMin product was more effective than either of the other products. For the air stimulus in the NovaMin group, 58% of subjects improved at each time point compared with 26% for the SrCl2 group and 20% for the placebo group. These results demonstrate that the NovaMin dentifrice was more effective at reducing sensitivity compared with a commercial dentifrice and placebo control.

The effect of the ionic products of Bioglass dissolution on human osteoblasts growth cycle in vitro.

In this study, in order to observe the effect of Bioglass and its ionic products on human esteoblasts growth cycle in vitro, the ionic products of Bioglass have been introduced to a cell culture medium by dissolving Bioglass particles in Dulbecco's modified Eagle's medium (DMEM) at 37 degrees C for 24 h; this was used as the experimental medium, while DMEM without Bioglass modification was used as the control medium. Human osteoblasts isolated from trabecular bone were treated by the two media and the timing of the osteoblast growth cycle was examined. Cell growth curves were derived after 7 days. Also, human osteoblasts were treated for 1-6 days by the two media, and the G(1), S, G(2) phase percentages of osteoblasts were recorded by flow cytometry every day, resulting in the cell proliferation activity index: SPF (S-phase fraction) and PI (proliferation index). The difference in cell growth was shown after the second day of culture (p < 0.01), and cell growth in the experimental groups was greater than in control groups. The SPF and PI of the experimental groups were also higher than the control groups in 2 days of culture (p < 0.05 and p < 0.01), which indicates that the growth cycle of the human osteoblasts in experimental medium is about 2 days. In conclusion, Bioglass can promote osteoblast proliferation, reducing the human osteoblast growth cycle to pass through G(1) and S phase and then enter G(2) phase quickly.

Anti-gingivitis effect of a dentifrice containing bioactive glass (NovaMin) particulate.

BACKGROUND: The objective of this pilot clinical trial was to evaluate the anti-gingivitis and anti-plaque effects of a dentifrice containing bioactive glass (NovaMin) compared with a placebo control dentifrice in a 6 weeks clinical study. METHODS: The study design was a randomized, double-blinded, controlled clinical trial. One hundred volunteers took part in the study and were matched for plaque index (PLI), gingival bleeding index (GBI), age and gender. The protocol was reviewed and approved by the Ethical Committee of the University. The subjects received a supragingival prophylaxis to remove all plaque, calculus and extrinsic stain. Following the baseline examination, subjects were instructed to brush with their assigned dentifrice and toothbrush. The PLI and GBI were determined for the baseline and 6 weeks. The data were analysed using a repeated-measures anova conducted on the two dependent measures to compare the effect between the test and control group. RESULTS: Ninety-five subjects finished the study. The results showed that the PLI (baseline=1.54, 6 weeks=1.29) and GBI (baseline=1.14, 6 weeks=0.47) were significantly reduced, respectively, over the 6 weeks period in the test group (p<0.001 for each measure). There was a 58.8% reduction in gingival bleeding and a 16.4% reduction in plaque growth. There was no difference of the PLI (baseline=1.60, 6 weeks=1.57) and GBI (baseline=1.18, 6-week=1.02) over the 6 week period in the control group. CONCLUSION: This study demonstrated that a dentifrice containing NovaMin significantly improves oral health as measured by a reduction in gingival bleeding and reduction in supragingival plaque compared with a negative dentifrice over the 6 weeks study period.

Bioactivity of tape cast and sintered bioactive glass-ceramic in simulated body fluid.

A common ceramic processing technique, tape casting, was used to produce thin, flexible sheets of bioactive glass (Bioglass 45S5) particulate in an organic matrix. Tape casting offers the possibility of producing three-dimensional shapes, as the final material is built up layer by layer. Bioactive glass tapes were sintered together to form small discs for in vitro bioactivity testing in simulated body fluid (SBF). Four different sintering schedules were investigated: 800, 900, and 1000 degrees C for 3 h; and 1000 degrees C for 6 h. Each schedule produced a crystalline material of major phase Na2Ca2Si3O9. Tape cast and sintered bioactive glass-ceramic processed at 1000 degrees C formed crystalline hydroxyapatite layers after 20-24 h in SBF as indicated by Fourier transform infrared spectroscopy, Scanning electron microscopy, and EDS data. FTIR revealed that the greatest amount of hydroxyapatite formation after 2 h was observed for samples sintered at 900 degrees C. The differences in bioactive response were likely caused by the variation in the extent of sintering and, consequently, the amount of surface area available for reaction with SBF.