In Vitro Ability of a Novel Nanohydroxyapatite Oral Rinse to Occlude Dentine Tubules.

Objectives. The aim of the study was to investigate the ability of a novel nanohydroxyapatite (nHA) desensitizing oral rinse to occlude dentine tubules compared to selected commercially available desensitizing oral rinses. Methods. 25 caries-free extracted molars were sectioned into 1 mm thick dentine discs. The dentine discs (n = 25) were etched with 6% citric acid for 2 minutes and rinsed with distilled water, prior to a 30-second application of test and control oral rinses. Evaluation was by (1) Scanning Electron Microscopy (SEM) of the dentine surface and (2) fluid flow measurements through a dentine disc. Results. Most of the oral rinses failed to adequately cover the dentine surface apart from the nHa oral rinse. However the hydroxyapatite, 1.4% potassium oxalate, and arginine/PVM/MA copolymer oral rinses, appeared to be relatively more effective than the nHA test and negative control rinses (potassium nitrate) in relation to a reduction in fluid flow measurements. Conclusions. Although the novel nHA oral rinse demonstrated the ability to occlude the dentine tubules and reduce the fluid flow measurements, some of the other oral rinses appeared to demonstrate a statistically significant reduction in fluid flow through the dentine disc, in particular the arginine/PVM/MA copolymer oral rinse

Bioactive glass engineered coatings for Ti6Al4V alloys: Influence of strontium substitution for calcium on sintering behaviour

NOTICE: this is the author’s version of a work that was accepted for publication in JOURNAL OF NON-CRYSTALLINE SOLIDS. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in JOURNAL OF NON-CRYSTALLINE SOLIDS, [VOL 356, ISSUE 44-49, (2010), DOI 10.1016/j.jnoncrysol.2010.05.01

High phosphate content significantly increases apatite formation of fluoride-containing bioactive glasses

NOTICE: this is the author’s version of a work that was accepted for publication in Acta Biomaterialia. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Acta Biomaterialia, [VOL 7, ISSUE 4, (2001)] DOI: 10.1016/j.actbio.2010.11.03

Comparing the Air Abrasion Cutting Efficacy of Dentine Using a Fluoride-Containing Bioactive Glass versus an Alumina Abrasive: An In Vitro Study.

Air abrasion as a caries removal technique is less aggressive than conventional techniques and is compatible for use with adhesive restorative materials. Alumina, while being currently the most common abrasive used for cutting, has controversial health and safety issues and no remineralisation properties. The alternative, a bioactive glass, 45S5, has the advantage of promoting hard tissue remineralisation. However, 45S5 is slow as a cutting abrasive and lacks fluoride in its formulation. The aim of this study was to compare the cutting efficacy of dentine using a customised fluoride-containing bioactive glass Na0SR (38-80 μm) versus the conventional alumina abrasive (29 μm) in an air abrasion set-up. Fluoride was incorporated into Na0SR to enhance its remineralisation properties while strontium was included to increase its radiopacity. Powder outflow rate was recorded prior to the cutting tests. Principal air abrasion cutting tests were carried out on pristine ivory dentine. The abrasion depths were quantified and compared using X-ray microtomography. Na0SR was found to create deeper cavities than alumina (p < 0.05) despite its lower powder outflow rate and predictably reduced hardness. The sharper edges of the Na0SR glass particles might improve the cutting efficiency. In conclusion, Na0SR was more efficacious than alumina for air abrasion cutting of dentine

The Effect of Bioactive Glasses in Air Abrasion Procedures

Objective: To analyse the effect of particle size and shape of a new bioactive glass BioMinF® on air abrasion compared to an air polishing powder (Sylc®) using an enamel substitute material (Macor®). Method: The materials used in the study were: 1) Macor®, (Precision Ceramics UK) 2) BioMinF®: 500gm of glass frit (Cera Dynamics Ltd, UK) and 3) Sylc®: Sylc 45S5 glass (Velopex International, UK). An AquaCare Air Abrasion & Polishing System (Velopex) with a hand piece with a 0.8 mm diameter tip was used with a 2mm thick Macor® sheet with a feed rate of 1 and an air pressure of 2 bar. The BioMinF glass was milled for 45 seconds in five batches each containing 100 gm of BioMinF® frit using a milling machine (Gy-Ro Mill, Glen Creston, and London). The angular particles produced were separated using different sieves to produce <38 micron, 38-63 microns, 63-80 microns, 80-125 microns and 125-250 microns particle size(s) respectively. To obtain the rounded particles, samples of 38-63, 63-80 and 80-125 micron powders were ball milled for 20 minutes. Evaluation of the samples was undertaken using Particle size Analysis, SEM and White Light Profilometry techniques. Results: Particle size, has a direct effect on air abrasion with abrasivity correlating with the D90 particle size. Sylc® was demonstrated to be more abrasive than BioMinF®. Conclusion: The results from the present study would suggest that air polishing with BioMinF® would be a better choice for polishing enamel with the advantage of localized fluoride release. However further studies are required using different substrates that more closely mimic human enamel

Quantification of Tooth Wear by Selected Desensitizing Polishing Pastes Using White Light Profilometry

Objectives: To analyse tooth wear using white light non-contact profilometry following the polishing of the tooth surface with selected polishing pastes. Methods: Three polishing pastes containing a range of particles sizes and different coarseness (extra-fine, medium, course) were compared with commercially available prophylaxis pastes (Nupro with Novamin® and Nupro with Fluoride) as controls. Particle size distribution was analysed using a using particle size analyser and quantified using Masterizer software. Teeth were in 70% ethanol prior to evaluation. 25 extracted human premolar teeth were distributed in five groups (n=5), and the teeth were mounted in a silicone putty matrix leaving an exposed buccal surface. White light profilometry with Proscan 2000 software was used to scan each tooth surface before and after polishing. Scantron ProForm software was used to superimpose images and measure surface loss and analyse the difference between the two surfaces-scans by the Proscan 2000 software. Results: Particle size analysis indicated that all samples consisted of a wide distribution of particles’ sizes (DX 10, 50, and 90). The course polishing paste had the largest DX 90 whereas Nupro with Fluoride had the lowest DX 90. The extra-fine pumice had the lowest DX 90, although this paste had larger values for DX 10 and DX 50 compared to the medium paste. The volume tooth loss analysis demonstrated that the course pumice had the most tooth surface loss compared to the extra-fine pumice which had the least amount of tooth surface loss. The average volume loss per group was 0.808, 0.022, 0.014, 0.022, 0.026 (course, medium, extra-fine, Nupro with Fluoride, and Nupro with Novamin®) respectively. Conclusions: The results indicated that the larger the DX 90 within the paste, the more tooth surface loss occurred due to the abrasivity of the paste. There was however minimal or no significant difference in the amount of tooth loss between the control polishing pastes

Zinc bioglasses regulate mineralization in human dental pulp stem cells

China Scholarship Council (CSC

The In vitro Effectiveness of Oxalate Based Desensitizing Products on Tubular Occlusion

Introduction: Dentine hypersensitivity (DH) is one of the most common clinically encountered conditions globally, affecting up to 74%. It has been described as a short, sharp pain resulting from changes in the fluid flow of exposed dentinal tubules, in response to physical and chemical stimuli. Objective: To compare the effectiveness of oxalate containing desensitizing products in reducing both dentine permeability and tubular occlusion vs. a control product using a recognized in vitro model. Methods: Three oxalate containing products were tested (Listerine® Advanced Defence Sensitive [LADS] mouth rinse, a 3% oxalate solution and an oxalate containing herbal toothpaste), vs. an artificial saliva control. The permeability of the acid-etched dentine discs was measured by hydraulic conductance (Lp). Dentine discs were examined using scanning electron microscopy and energy dispersive X-ray spectroscopy. After establishing the baseline permeability of the acid-etched dentine discs, discs (n=4) were randomly treated with the desensitizing products together with the addition of artificial saliva for 2 mins, followed by rinsing with distilled water (60 s). Permeability was measured at 30 s intervals for a total of 150 s. The occluded discs were acid challenged to assess tubular occlusion stability following the application of both the test and control products. Results: The oxalate containing desensitizing products in combination with artificial saliva significantly occluded the dentinal tubules by up to 65%, in comparison to the artificial saliva control that occluded ≤21% of the dentinal tubules. The occlusion associated with the oxalate containing desensitizing agents was substantially more stable in resisting an acid challenge compared to the control as determined by hydraulic conductance. Furthermore, the SEM images of the oxalate containing desensitising agents and control were consistent with the hydraulic conductance data. Of interest was that the oxalate containing herbal toothpaste deposited more precipitation on the surface than inside the tubules. The EDX analysis confirmed the presence of oxalates, calcium, and other ingredients of toothpaste. The results from the present study are in broad agreement with those of a previous study in that an oxalate containing mouth rinse provided a more stable tubular occlusion which was more resistant to an acid challenge compared to the other test products. Conclusion: Oxalate containing desensitizing agents were significantly more effective in occluding the dentinal tubules vs. an artificial saliva control. These results are of clinical significance as they demonstrate that oxalate containing desensitizing agents provide both significant and stable tubular occlusion of the open dentinal tubules following an acidic challenge