Effect of Model Variables on in vitro Erosion

2015 ◽  
Vol 49 (5) ◽  
pp. 508-514 ◽  
Author(s):  
Miten Mistry ◽  
Shanshan Zhu ◽  
Rebecca Moazzez ◽  
Nora Donaldson ◽  
David W. Bartlett
Keyword(s):  
Acrylic Resin ◽  
Smear Layer ◽  
Step Height ◽  
Tooth Surface ◽  
Height Loss ◽  
Permanent Molar ◽  
Detailed Method ◽  
Tooth Surfaces ◽  
Molar Teeth

The aim of this study was to investigate the effects of tooth type (molar/premolar), tooth surface (buccal/lingual), smear layer or no smear layer, storage of specimens in deionised water, mode and speed of agitation, and rinsing method between cycles on mean step height loss and Knoop microhardness (KHN) change. Polished human enamel specimens embedded in acrylic resin were prepared from sound permanent molar and premolar tooth surfaces. A 0.3% (pH 3.2) solution of citric acid was used to erode the specimens, in a cycling procedure, consisting of 10 min immersion followed by rinsing in deionised water for 30 s with a spray bottle, for 5 cycles. The specimens were analysed with a non-contact white light profilometer and KHN. Molar teeth (148.99 ± 24.49 KHN) and buccal surfaces (155.62 ± 30.35 KHN) produced significantly less microhardness change compared to premolar (186.40 ± 20.74 KHN) and lingual surfaces (179.76 ± 23.21 KHN; p < 0001). The effect of storage and rinsing showed little difference in mean step height loss (<1 µm) and microhardness change. With no smear layer a significantly lower mean step height loss and microhardness change (p < 0.001) was observed. Agitation was performed with Orbital, Gyro and See-Saw rockers at 30, 40, 60, and 70 rpm. The mean step height loss was largest for See-Saw at 70 rpm (11.73 ± 0.91 μm) and lowest for Orbital at 30 rpm (2.76 ± 1.12 μm). A statistical difference was found between all types of agitation and speeds (p < 0.001). In conclusion, this study has shown that the variables investigated here have a significant impact on the measurable outcome, highlighting the importance of accurate and detailed method sections.

scholarly journals Exopolysaccharides Produced by Streptococcus mutans Glucosyltransferases Modulate the Establishment of Microcolonies within Multispecies Biofilms

2010 ◽  
Vol 192 (12) ◽  
pp. 3024-3032 ◽  
Author(s):  
H. Koo ◽  
J. Xiao ◽  
M. I. Klein ◽  
J. G. Jeon
Keyword(s):  
Streptococcus Mutans ◽  
Extracellular Polysaccharide ◽  
Fluorescence Labeling ◽  
Tooth Surface ◽  
Bacterial Cells ◽  
Actinomyces Naeslundii ◽  
Multispecies Biofilm ◽  
Tooth Surfaces ◽  
Glucan Synthesis

ABSTRACT Streptococcus mutans is a key contributor to the formation of the extracellular polysaccharide (EPS) matrix in dental biofilms. The exopolysaccharides, which are mostly glucans synthesized by streptococcal glucosyltransferases (Gtfs), provide binding sites that promote accumulation of microorganisms on the tooth surface and further establishment of pathogenic biofilms. This study explored (i) the role of S. mutans Gtfs in the development of the EPS matrix and microcolonies in biofilms, (ii) the influence of exopolysaccharides on formation of microcolonies, and (iii) establishment of S. mutans in a multispecies biofilm in vitro using a novel fluorescence labeling technique. Our data show that the ability of S. mutans strains defective in the gtfB gene or the gtfB and gtfC genes to form microcolonies on saliva-coated hydroxyapatite surfaces was markedly disrupted. However, deletion of both gtfB (associated with insoluble glucan synthesis) and gtfC (associated with insoluble and soluble glucan synthesis) is required for the maximum reduction in EPS matrix and biofilm formation. S. mutans grown with sucrose in the presence of Streptococcus oralis and Actinomyces naeslundii steadily formed exopolysaccharides, which allowed the initial clustering of bacterial cells and further development into highly structured microcolonies. Concomitantly, S. mutans became the major species in the mature biofilm. Neither the EPS matrix nor microcolonies were formed in the presence of glucose in the multispecies biofilm. Our data show that GtfB and GtfC are essential for establishment of the EPS matrix, but GtfB appears to be responsible for formation of microcolonies by S. mutans; these Gtf-mediated processes may enhance the competitiveness of S. mutans in the multispecies environment in biofilms on tooth surfaces.

scholarly journals Evaluation of a novel fixed-space maintainer made of light-cured acrylic resin: an in vitro study

BDJ Open ◽  
2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Yasser R. Souror ◽  
Tayseer Maaly ◽  
Mohammed Sameer Khawandanah
Keyword(s):  
Flexural Strength ◽  
Bond Strength ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Tooth Surface ◽  
Significant Difference ◽  
Space Maintainer ◽  
Fixed Space

Abstract To evaluate a fixed-space maintainer made of light-cure acrylic resin (LCAR) for its flexural and shear bond strength using different bonding systems to the enamel. 45 extracted primary teeth were selected. They were randomly divided into three equal groups (n = 15) along with the type of adhesive system (Tetric Flow, Transbond XT, and Fuji Ortho LC) used for bonding (LCAR) to the tooth surface. Surfaces were treated; LCAR was attached to the treated surfaces using a split Teflon mold. For flexural strength testing, ten bars of LCAR were made using another Teflon-split mold. Shear bond strength and mean flexural strength values were evaluated by a universal testing machine. The highest values of bond strength were recorded for Transbond XT, followed by Tetric Flow, while the lowest values were for Fuji Ortho LC. Various groups had a significant difference as investigated by ANOVA. ARI scores showed no significant difference in debond sites. Mean value and standard deviation of flexural strength for LCAR were 82.83  ± 5.2. LCAR has superior mechanical properties and could be an alternative to currently-in-use space maintainer though in vivo and in vitro trials are needed to progress the ultimate design of LCAR.

scholarly journals Cup-Shaped Tooth Wear Defects: More than Erosive Challenges?

2019 ◽  
Vol 53 (4) ◽  
pp. 467-474 ◽  
Author(s):  
Jan L. Ruben ◽  
F. Joost M. Roeters ◽  
Gert-Jan Truin ◽  
Bas A.C. Loomans ◽  
Marie-Charlotte D.N.J.M. Huysmans
Keyword(s):  
Tooth Wear ◽  
Underlying Mechanism ◽  
Tissue Loss ◽  
Height Loss ◽  
Average Height ◽  
Micro Computed Tomography ◽  
Significant Difference ◽  
Before And After ◽  
Tooth Surfaces

Background/Aim: The underlying mechanism of the development of cups and grooves on occlusal tooth surfaces is still unclear. The aim of this study was to evaluate factors contributing to in vitro cup formation, in order to elucidate the clinical process. Methods: A total of 48 extracted human molar teeth were exposed to acidic aqueous solutions at pH of 4.8 and 5.5 in constant motion, in combination with different loading conditions: no load (0N group, control), 30 N (30N group) or 50 N (50N group) (n = 8 per group). Before and after 3 months of exposure (1,422,000 loading cycles), the samples were scanned using a non-contact profilometer. Pre- and post-exposure scans were subtracted and height loss and volume tissue loss were calculated. Representative samples with wear and cupping lesions were imaged using scanning electron microscopy, light microscopy and micro-computed tomography. Results: Average height and volume tissue loss at pH 5.5 was 54 µm and 3.4 mm3 (0N), 52 µm and 3.4 mm3 (30N) and 58 µm and 3.7 mm3 (50N), respectively, with no statistically significant differences. Average height and volume loss at pH 4.8 were 135 µm and 8.7 mm3 (0N), 172 µm and 12.6 mm3 (30N) and 266 µm and 17.8 mm3 (50N), respectively, with a statistically significant difference between 0N and 50N (p < 0.002). Cup-shaped lesions had formed only at pH of 4.8, in the 30N and 50N groups. Conclusion: The study showed that a cup can arise fully in enamel and that mechanical loading in addition to erosive challenges are required.

scholarly journals SEM Evaluation of Tooth Surface after a Composite Filling Removal Using Er:YAG Laser, Drills with and without Curettes, and Optional EDTA or NaOCl Conditioning

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4469
Author(s):  
Jan Kiryk ◽  
Jacek Matys ◽  
Kinga Grzech-Leśniak ◽  
Marzena Dominiak ◽  
Małgorzata Małecka ◽  
...  
Keyword(s):  
Surface Structure ◽  
Sodium Hypochlorite ◽  
Er:Yag Laser ◽  
Mechanical Damage ◽  
Smear Layer ◽  
Tooth Surface ◽  
Dentinal Tubules ◽  
Sem Image ◽  
Diamond Drill ◽  
Tooth Surfaces

(1) Background: This study aimed to evaluate the microporosity of the tooth surface structure adjacent to the cemento-enamel junction (CEJ) after the removal of composite fillings with a drill in comparison with removal by an Er:YAG laser and after cleaning with a periodontal curette, chemical EDTA and NaOCl (sodium hypochlorite) conditioning. (2) Methods: The research material consisted of 30 extracted premolars with cervical composite fillings. The teeth were divided into six groups according to the method of tooth preparation: group G1 (n = 5)—a diamond drill; group G2 (n = 5)—a diamond drill + curette; group G3 (n = 5)—a diamond drill + 24% EDTA (PrefGel, Straumann, Switzerland); group G4 (n = 5)—an Er:YAG laser (LightWalker, Fotona, Ljubljana, Slovenia) set with the following parameters: power: 1.65 W (composite removal, CR), 1.2 (tooth conditioning, TC), energy: 110 mJ (CR), 80 mJ (TC), frequency: 15 Hz, pulse duration: 50 μs, tip diameter: 1 mm, air/fluid cooling: 4, distance 1.5 mm, energy density: 14.01 J/cm2 (CR), 10.19 J/cm2 (TC); group G5 (n = 5)—an Er:YAG laser + 2% sodium hypochlorite (NaOCl); group G6 (n = 5)—an Er:YAG laser + 5.25% NaOCl. In each tooth, three cavities were made and subjected to analysis. The dentin surface was evaluated using a scanning electron microscope (SEM). (3) Results: Groups G1 and G2 exhibited mechanical damage to the tooth surface structure caused by the rotary motion of a diamond drill. The SEM image showed a smear layer that could only be removed chemically using 24% EDTA gel (group G3). The tooth surfaces prepared with the Er:YAG laser (groups G4–G6) revealed a homogeneous structure without damage along with open dentinal tubules (without smear layer) and visible denaturation of collagen fibers. The sodium hypochlorite (NaOCl) conditioning did not increase the visibility of dentinal tubules. (4) Conclusions: Dentin surfaces have open dentinal tubules after removal of the composite filling using the Er:YAG laser and therefore do not require additional NaOCl conditioning.

scholarly journals Comparison of Canal Transportation, Separation Rate, and Preparation Time between One Shape and Neoniti (Neolix): An In Vitro CBCT Study

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Maryam Kuzekanani ◽  
Faranak Sadeghi ◽  
Nima Hatami ◽  
Maryam Rad ◽  
Mansoureh Darijani ◽  
...  
Keyword(s):  
File Systems ◽  
In Vitro Study ◽  
Acrylic Resin ◽  
Preparation Time ◽  
Technical Performance ◽  
Molar Teeth ◽  
Canal Transportation ◽  
Time Required ◽  
Instrument Separation

Purpose. This in vitro study compared root canal preparation in curved mesiobuccal canals of molar teeth using either the One Shape™ or the Neoniti (Neolix) rotary NiTi single-file systems, assessing canal transportation, instrument separation and time required for preparation. Methods. Extracted maxillary and mandibular human molar teeth with mesiobuccal canals having apical angles of curvature between 25 and 35o were selected and embedded in acrylic resin blocks, and an initial CBCT was taken. The teeth were divided into two equal groups (n = 20), and the canals were cleaned and shaped using either Neoniti™ or One Shape™ engine-driven NiTi rotary files. Each individual instrument was used to prepare 5 canals. The time required for the preparation of each canal was recorded. Postpreparation CBCT scans were taken and used to determine the extent of canal transportation at levels of 2, 4, 6, and 8 mm from the apex. The Kolmogorov–Smirnov test for normality was applied, and then, datasets were compared using independent t-tests, with a threshold of P < 0.05 . Results. Neoniti rotary files caused significantly less canal transportation of the curved canals ( P = 0.0001 ). On the other hand, the time required for canal preparation was significantly shorter for One Shape ( P = 0.0001 ). No instrument separation was recorded in both groups. Conclusion. Based on these results, the Neoniti™ rotary file system is preferred because it maintains the original shape of curved root canals better than One Shape™; even though this benefit comes at the cost of an increase in preparation time in clinical practice, the better technical performance may be more important than a difference in procedural time.

scholarly journals An Intraoral OCT Probe to Enhanced Detection of Approximal Carious Lesions and Assessment of Restorations

2020 ◽  
Vol 9 (10) ◽  
pp. 3257
Author(s):  
Hartmut Schneider ◽  
Martin Ahrens ◽  
Michaela Strumpski ◽  
Claudia Rüger ◽  
Matthias Häfer ◽  
...  
Keyword(s):  
Dental Treatment ◽  
Blind Spot ◽  
Tooth Surface ◽  
Posterior Teeth ◽  
Common Chronic Disease ◽  
Spectral Domain Oct ◽  
Diagnostic Potential ◽  
Tooth Surfaces

Caries, the world’s most common chronic disease, remains a major cause of invasive restorative dental treatment. To take advantage of the diagnostic potential of optical coherence tomography (OCT) in contemporary dental prevention and treatment, an intraorally applicable spectral-domain OCT probe has been developed based on an OCT hand-held scanner equipped with a rigid 90°-optics endoscope. The probe was verified in vitro. In vivo, all tooth surfaces could be imaged with the OCT probe, except the vestibular surfaces of third molars and the proximal surface sections of molars within a "blind spot" at a distance greater than 2.5 mm from the tooth surface. Proximal surfaces of 64 posterior teeth of four volunteers were assessed by intraoral OCT, visual-tactile inspection, bitewing radiography and fiber-optic transillumination. The agreement in detecting healthy and carious surfaces varied greatly between OCT and established methods (18.2–94.7%), whereby the established methods could always be supplemented by OCT. Direct and indirect composite and ceramic restorations with inherent imperfections and failures of the tooth-restoration bond were imaged and qualitatively evaluated. The intraoral OCT probe proved to be a powerful technological approach for the non-invasive imaging of healthy and carious hard tooth tissues and gingiva as well as tooth-colored restorations.

scholarly journals Estimation of the frequency of second mesiobuccal root canal in maxillary first permanent molar teeth in subjects visiting teaching dental hospitals of Peshawar.

2020 ◽  
Vol 27 (10) ◽  
pp. 2203-2209
Author(s):  
Ambereen Humayun ◽  
Munawar Aziz Khattak ◽  
Aamir Mehmood Khan ◽  
Nighat Ara ◽  
Farooq Khan ◽  
...  
Keyword(s):  
Root Canal ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Permanent Molar ◽  
Dental Hospital ◽  
Molar Teeth ◽  
Clearing Technique ◽  
And Gender ◽  
Second Mesiobuccal Canal

Objectives: To determine the frequency of second mesiobuccal canal (MB2) in a sample of 223 extracted maxillary permanent 1st molars. Study Design: In-vitro Cross-sectional study. Setting: Department of Endodontic at Peshawar Dental Hospital. Period: June 2019-Nov 2019. Material & Methods: The samples were processed with application of the Clearing Technique which includes demineralization with nitric acid, dehydration with ethanol and clearing with methyl salicylate. The samples were classified according to Weine’s system of root canal classification. Results: Among the 223 samples, 30% were found to have Weine’s type1 root canal in the mesiobuccal root (second mesiobuccal canal absent).  Second mesiobuccal canal was present in majority of the samples (70%) with Weines type2 (2-1) predominant with 23.32%, Weines type3 (2-2) present in 15.7% and Weines type 4 (1-2) present in 21% of the samples. 9% of the samples could not fit into Weines classification so they were placed in Vertuccis classification for root canal system type 6 (2-1-2). Conclusion: The present study concludes that the second mesiobuccal canal is more frequently found in maxillary permanent 1st molar teeth than our textbooks report, irrespective of quadrant and gender. Therefore, time should be given to evaluation of its anatomy by the clinician before starting the root canal treatment for the greater good of the community.

scholarly journals Phosphopeptides derived from human salivary acidic proline-rich proteins. Biological activities and concentration in saliva

1990 ◽  
Vol 270 (2) ◽  
pp. 297-304 ◽  
Author(s):  
G Madapallimattam ◽  
A Bennick
Keyword(s):  
Biological Activities ◽  
Human Saliva ◽  
Tooth Surface ◽  
Mineral Formation ◽  
Parotid Saliva ◽  
Whole Saliva ◽  
Tooth Surfaces ◽  
In Vivo Degradation

Human saliva contains a large number of phosphopeptides derived by cleavage of acidic proline-rich proteins (APRPs). These peptides were purified by column chromatography and they constituted 0.5% of APRPs in parotid saliva, but 11% of APRPs in saliva expectorated from the mouth (whole saliva), indicating that there is considerable cleavage of APRPs after secretion from the gland. Similarly to APRP, the phosphopeptides bind Ca2+, but they accounted for only 4% of protein-bound Ca2+ in whole saliva. APRPs as well as the phosphopeptides inhibited formation of hydroxyapatite, but, whereas 19-20 micrograms of APRP was needed for 50% inhibition, only 0.7-3.3 micrograms of purified peptides was needed for the same degree of activity, and the phosphopeptides accounted for 18% of total inhibitory activity in whole saliva. All phosphopeptides adsorbed on hydroxyapatite in vitro, and adsorption of phosphopeptides on tooth surfaces in vivo could also be demonstrated, indicating that they would be able to inhibit unwanted mineral formation on the tooth surface in vivo. Degradation of APRPs after secretion therefore does not lead to a loss of their biological activities.

scholarly journals Tooth-Binding Micelles for Dental Caries Prevention

2009 ◽  
Vol 53 (11) ◽  
pp. 4898-4902 ◽  
Author(s):  
Fu Chen ◽  
Xin-Ming Liu ◽  
Kelly C. Rice ◽  
Xue Li ◽  
Fang Yu ◽  
...  
Keyword(s):  
Caries Prevention ◽  
Tooth Surface ◽  
Hydrodynamic Diameter ◽  
Local Concentration ◽  
Binding Ability ◽  
Biofilm Inhibition ◽  
Tooth Surfaces ◽  
Delivery Platform ◽  
Inhibition Studies

ABSTRACT Maintenance of the effective local concentration of antimicrobials on the tooth surface is critical for the management of cariogenic bacteria in the oral cavity. We report on the design of a simple tooth-binding micellar drug delivery platform that would effectively bind to tooth surfaces. To achieve tooth-binding ability, the chain termini of biocompatible Pluronic copolymers were modified with a biomineral-binding moiety (i.e., alendronate). The micelles formulated with this polymer were shown to be able to swiftly (<1 min) bind to hydroxyapatite (HA; a model tooth surface) and gradually release the encapsulated model antimicrobial (farnesol). These tooth-binding micelles were negatively charged and had an average effective hydrodynamic diameter of less than 100 nm. In vitro biofilm inhibition studies demonstrated that the farnesol-containing tooth-binding micelles were able to provide significantly stronger inhibition of Streptococcus mutans UA159 biofilm formation on HA discs than the untreated blank control micelles (P < 0.0001). Upon further optimization, this delivery platform could provide an effective tool for caries prevention and treatment.

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