Search results for "Tooth"

Effect of cavity preparation instruments (oscillating or rotating) on the composite-dentin interface in primary teeth.

2003

Abstract Objectives: To evaluate the effect of preparation of instruments on the interfacial integrity between cavity wall and composite restoration. Methods: Two class II slot preparations were done in 10 primary teeth either with SonicSys® or with a conventional bur. The cavities were filled using an adhesive system. One layer of a flowable composite and one layer of a condensable composite were applied. The specimens were analyzed by confocal laser scanning microscopy. Results: In the SonicSys® group the mean thickness of the hybrid layer was 6.12 (0.60) μm; in the control group it was 6.04 (0.63) μm. The difference was not statistically significant. Two fractures were observed in one to…

The Use of Atomic Force Microscopy in Determining the Stiffness and Adhesion Force of Human Dentin After Exposure to Bleaching Agents

2009

Introduction: Oxidant bleaching agents may induce several alterations on mineralized teeth tissues. Our aim is to study,at the ultrastructurallevel,mechanicalmodifications induced on dentin after exposure to different bleaching agents.Methods: Nanoindentation performed with atomic force microscopy was used to measure changes in dentin stiffness as well as the adhesion force between the tip and the tissue both in intertubular and peritubulardentin.Foreachspecimen,dentinlocalization, and bleaching agent, 100 independent nanoindentations were performed. Carbamide peroxide (30%) and hydrogenperoxide(35%) wereusedasbleaching agents. Results: A significant reduction of both stiffness and adhesion…

In vivo and in vitro effects of an Er:YAG laser, a GaAlAs diode laser, and scaling and root planing on periodontally diseased root surfaces: A compar…

2003

Background and Objectives The aim of the present histologic study was to compare the in vivo and in vitro effects of an erbium: yttrium, aluminum, and garnet (Er:YAG) laser (ERL), combined with a fluorescent calculus detection system, a diode laser (DL) and scaling and root planing (SRP) on periodontally diseased root surfaces. Study Design/Materials and Methods Twenty-four single rooted teeth, considered for extraction due to severe periodontal destruction, were included in the study. Prior to extraction all mesial root surfaces were randomly assigned to the following treatment groups: (1) ERL combined with a calculus detection system with fluorescence induced by 655 nm InGaAsP DL radiatio…

Strukturelle Veränderungen in säuregeätztem Schmelz im konfokalen Laser-Scanning-Mikroskop

1996

The aim of the present investigation was to elucidate structural alternations in enamel subjected to acid etch technique and treatment under remineralizing conditions by means of a new microscopy technique known as confocal laser scanning microscopy (CLSM). Blocks of enamel were treated with 37% phosphoric acid and exposed for 3 weeks to an oral environment. Tomographic CLSM images were subsequently obtained and compared with controls. CLSM proved to be a reliable, highly reproducible and simple method of qualitative assessment of structural changes occurring on the surface of enamel and in areas below the surface as deep as 100 microns or more. Structural alterations associated with acid a…

The effect of oxalate-based desensitizers on the microleakage and shear bond strength of resin modified glass ionomer

2017

Background The first line of intervention to alleviate tooth sensitivity is to use dentin desensitizers such as oxalate-based desensitizers. When the dentin sensitivity continues even after application of desensitizers the next intervention would be restoration of the lesion. The aim of this in vitro study was to investigate the effect of prior application of oxalate-based desensitizer on the marginal microleakage and shear bond strength of resin modified glass ionomer (RMGI) restorations. Material and methods In order to prepare the specimens for microleakage test standard class v cavities were prepared on buccal surfaces of 45 teeth. The specimens were randomly divided into three equal gr…

Fluoride-induced precipitates on enamel surface and subsurface areas visualised by electron microscopy and confocal laser scanning microscopy

1997

The present study examined the enamel surface after in vitro topical treatments with a neutral 2% NaF solution. For minimising the risk of artefacts, samples were inspected without pre-treatment as fresh, naturally wet specimens by complementary techniques: variable pressure electron microscopy (VP-SEM) and confocal laser scanning microscopy (CLSM). VP-SEM provided information on the surface morphology, whereas CLSM allowed non-destructive visualisation of subsurface areas. Neutral NaF solutions induced globular precipitates on the enamel surfaces. If the globules formed may be described as "calcium fluoride like material", the additional information of this experiment is that, after intera…

A portable fiber-optic raman spectrometer concept for evaluation of mineral content within enamel tissue

2017

BACKGROUND Measurement of tooth enamel mineralization using a clinically viable method is essential since variation of mineralization may be used to monitor caries risk or in assessing the effectiveness of remineralization therapy. Fiber optic Raman systems are becoming more affordable and popular in context of biomedical applications. However, the applicability of fiber optic Raman systems for measurement of mineral content within enamel tissue has not been elucidated significantly in the prior literature. MATERIAL AND METHODS Human teeth with varying degrees of enamel mineralization were selected. In addition alligator, boar and buffalo teeth which have increasing amount of mineral conten…

OR 48 Quantitative pulp diagnostic by means of optical transillumination

1997

Inclusion of the periodontal ligament in studies on the biomechanical behavior of fiber post-retained restorations: An in vitro study and three-dimen…

2016

Endodontically treated teeth are known to have reduced structural strength. Periodontal ligament may influence fracture resistance. The purpose of this study was to assess the influence of including the periodontal ligament in biomechanical studies about endodontically treated and restored teeth. Forty human maxillary central incisors were treated endodontically and randomly divided into four groups: non-crowned (with and without an artificial ligament) and crowned (with and without an artificial ligament) with glass-ceramic crowns. All groups received prefabricated glass-fiber posts and a composite resin core. Specimens were tested, under a flexural–compressive load, until failure occurre…

Incremental lines in root cementum of human teeth: an approach to their ultrastructural nature by microscopy.

1998

In ground sections of human teeth, root cementum shows under the light microscope as alternating, almost concentric, dark and light rings. In paleontology and forensic medicine, the number of these incremental lines or annulations is used to derive the age-at-death of the individual. To find the ultrastructural features underlying these cemental annulations, we used bright-field light microscopy (LM), confocal laser scanning microscopy (CLSM), transmission electron microscopy (TEM), and electron-dispersive x-radiation (EDX) in a scanning electron microscope (SEM). Annulations visible in ground sections of about 100-μm thickness were no longer visible in semi-thin sections (thickness, 1-2 μ…