Search results for "Enamel"
showing 10 items of 277 documents
Effect of water contamination on the shear bond strength of five orthodontic adhesives
2010
Objectives: To evaluate the shear bond strength and site of failure of brackets bonded to dry and wet enamel. Study design: 50 teeth were divided into ten groups of 5 teeth each (10 surfaces). In half the groups enamel was kept dry before bonding, and in the other half distilled water was applied to wet the surface after etching. The following groups were established: 1)Acid/Transbond-XT (dry/wet) XT; 2) Transbond Plus Self Etching Primer (TSEP)/Transbond-XT paste (dry/wet); 3) Concise (dry), Transbond MIP/Concise (wet), 4) FujiOrtho-LC (dry/ wet); 5) SmartBond (dry/wet). Brackets were bonded to both buccal and lingual surfaces. Specimens were stored in distilled water (24 hours at 37ºC) an…
Casein phosphopeptide-amorphous calcium phosphate effects on brackets shear bond strength and enamel damage
2017
Background The aim of study was to evaluate the application of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride regarding their effect on the shear bond strength (SBS), bond failure pattern of brackets using the adhesive remnant index (ARI) and assessing the quality of enamel surface using the enamel damage index (EDI). Material and methods Sixty extracted premolar teeth were randomly divided into four groups regarding pretreatment application of CPP-ACP and fluoride. Brackets were bonded using the conventional method. Specimens were thermocycled for 1000 cycles and were subsequently tested for the SBS in a universal testing machine. After debonding, the teeth were e…
Resistance of bonded premolars to four artificial ageing models post enamel conditioning with a novel calcium-phosphate paste
2020
Background This in vitro study compares a novel calcium-phosphate etchant paste to conventional 37% phosphoric acid gel for bonding metal and ceramic brackets by evaluating the shear bond strength, remnant adhesive and enamel damage following water storage, acid challenge and fatigue loading. Material and Methods Metal and ceramic brackets were bonded to 240 extracted human premolars using two enamel conditioning protocols: conventional 37% phosphoric acid (PA) gel (control), and an acidic calcium-phosphate (CaP) paste. The CaP paste was prepared from β-tricalcium phosphate and monocalcium phosphate monohydrate powders mixed with 37% phosphoric acid solution, and the resulting phase was con…
In vitro bond strengths post thermal and fatigue load cycling of sapphire brackets bonded with self-etch primer and evaluation of enamel damage
2020
Background This in vitro study compares a self-etch primer (SEP) to an etch-and-rinse (EaR) for bonding sapphire brackets by evaluation of the enamel etch-pattern, shear bond strength, amount of remnant adhesive and enamel surface damage following thermal and fatigue cyclic loading. Material and Methods Ceramic (sapphire) brackets were bonded to 80 extracted human premolars using two enamel etching protocols: conventional EaR using 37% phosphoric acid (PA) gel (control), and a SEP (Transbond Plus). Each group was subdivided into two subgroups (n=20 teeth) according to the time of bracket debonding: after 24 h water storage or following 5000 thermo-cycles plus 5000 cycles fatigue loading, to…
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…
Effect of different bleaching protocols on whitening efficiency and enamel superficial microhardness
2018
Background Tooth bleaching is a popular aesthetic treatment to modify the color of teeth. Despite the extensive literature concerning the subject, there is still no consensus regarding the application mode of the different bleaching agents and their effect on enamel. Therefore, this study evaluated the influence of different bleaching protocols on whitening efficiency and enamel superficial hardness. Material and methods Bovine enamel fragments were embedded in acrylic resin and wet-sanded to obtain a flat buccal surface. The specimens were then randomly divided into 6 groups (n=10), based on the bleaching material [HP Maxx 35% (35% hydrogen peroxide), HP Blue 35% (35% hydrogen peroxide + C…
X-ray fluorescence investigation of gilded and enamelled silver: The case study of four medieval processional crosses from central Italy
2013
Abstract The presence of multilayered structures is common in such cultural artefacts as paintings, corroded metals, objects that underwent a whatever form of surface qualification. One of the most usual and complete ways to investigate such structures is observing a cross section, which requires sampling. There are however situations where at least part of the stratigraphic information can be derived non-destructively: the literature shows that X-ray fluorescence (XRF) has frequently been used, in recent years, for this purpose, with special regard to paintings and gilded metals. Aim of this paper is to further explore the suitability of XRF-based techniques to characterise multilayered st…
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…
Evaluation of surface roughness of enamel after various bonding and clean-up procedures on enamel bonded with three different bonding agents : an in-…
2016
Background The purpose of this study was to analyze and compare the enamel surface roughness before bonding and after debonding, to find correlation between the adhesive remnant index and its effect on enamel surface roughness and to evaluate which clean-up method is most efficient to provide a smoother enamel surface. Material and methods 135 premolars were divided into 3 groups containing 45 premolars in each group. Group I was bonded by using moisture insensitive primer, Group II by using conventional orthodontic adhesive and Group III by using self-etching primer. Each group was divided into 3 sub-groups on the basis of type of clean-up method applied i,e scaling followed by polishing, …
The effect of combining laser and nanohydroxy-apatite on the surface properties of enamel with initial defects
2017
Background The aim of this study was to evaluate the effect of combining fractional CO2 LASER and nanohydroxy apatite on surface microhardness and color of enamel with initial defects. Material and Methods Two types of nano hydroxylapatite (nHAP) was prepared; Pure hydroxyapatite (nHA) and Fluoro hydroxyapatite (nFHA), Sixty extracted premolar teeth without visible caries or structural defects on enamel surface were used, immersed in 10 ml of a demineralizing solution for 2 weeks to create artificial white spot lesions, they were randomly allocated into two groups; Group 1: nHA, Group 2: nFHA, each group is then subdivided into 2 subgroups (A and B) where two different in vitroremineralizat…