Scanning Electron Microscopy of the Human Enamel Surface Layer of Incipient Carious Lesions

1983 ◽  
Vol 17 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Y. Haikel ◽  
R.M. Frank ◽  
J.C. Voegel
2006 ◽  
Vol 30 (3) ◽  
pp. 247-250 ◽  
Author(s):  
Caio Zanet ◽  
Victor Arana-Chavez ◽  
Marcelo Fava

Acid etching promotes microporosities on enamel surface, which provide a better bonding surface to adhesive materials. The purpose of this study was to comparatively analyze the microstructure of enamel surface after etching with 37% phosphoric acid or with two self-etching primers, Non-rinse conditioner (NRC) and Clearfil SE Bond (CSEB) using scanning electron microscopy. Thirty sound premolars were divided into 3 groups with ten teeth each: Group 1: the buccal surface was etched with 37% phosphoric acid for 15 seconds; Group 2: the buccal surface was etched with NRC for 20 seconds; Group 3: the buccal surface was etched with CSEB for 20 seconds. Teeth from Group 1 were rinsed with water; teeth from all groups were air-dried for 15 seconds. After that, all specimens were processed for scanning electron microscopy and analyzed in a Jeol 6100 SEM. The results showed deeper etching when the enamel surface was etched with 37% phosphoric acid, followed by NRC and CSEB. It is concluded that 37% phosphoric acid is still the best agent for a most effective enamel etching.


2005 ◽  
Vol 13 (2) ◽  
pp. 204-211 ◽  
Author(s):  
Carolina Baptista Miranda ◽  
Clovis Pagani ◽  
Ana Raquel Benetti ◽  
Fábio da Silva Matuda

Since bleaching has become a popular procedure, the effect of peroxides on dental hard tissues is of great interest in research. Purpose: The aim of this in vitro study was to perform a qualitative analysis of the human enamel after the application of in-office bleaching agents, using Scanning Electron Microscopy (SEM). Materials and Methods: Twenty intact human third molars extracted for orthodontic reasons were randomly divided into four groups (n=5) treated as follows: G1- storage in artificial saliva (control group); G2- four 30-minute applications of 35% carbamide peroxide (total exposure: 2h); G3- four 2-hour exposures to 35% carbamide peroxide (total exposure: 8h); G4- two applications of 35% hydrogen peroxide, which was light-activated with halogen lamp at 700mW/cm² during 7min and remained in contact with enamel for 20min (total exposure: 40min). All bleaching treatments adopted in this study followed the application protocols advised by manufacturers. Evaluation of groups submitted to 35% carbamide peroxide was carried out after two time intervals (30 minutes and 2 hours per session), following the extreme situations recommended by the manufacturer. Specimens were prepared for SEM analysis performing gold sputter coating under vacuum and were examined using 15kV at 500x and 2000x magnification. Results: Morphological alterations on the enamel surface were similarly detected after bleaching with either 35% carbamide peroxide or 35% hydrogen peroxide. Surface porosities were characteristic of an erosive process that took place on human enamel. Depression areas, including the formation of craters, and exposure of enamel rods could also be detected. Conclusion: Bleaching effects on enamel morphology were randomly distributed throughout enamel surface and various degrees of enamel damage could be noticed. Clinical significance: In-office bleaching materials may adversely affect enamel morphology and therefore should be used with caution.


2019 ◽  
Vol 25 (4) ◽  
pp. 2744-2750
Author(s):  
Ekaterina Karteva ◽  
◽  
Neshka Manchorova-Veleva ◽  
Zhelyazko Damyanov ◽  
Teodora Karteva ◽  
...  

2020 ◽  
Vol 14 (02) ◽  
pp. 299-305
Author(s):  
Kiatanan Sugsompian ◽  
Ratchawan Tansalarak ◽  
Thosapol Piyapattamin

Abstract Objective This study aimed to compare the enamel surface roughness created by four polishing methods after debonding, by using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Materials and Methods Four experimental polishing groups (Sof-Lex disc, SD; sandblaster, SB; tungsten carbide bur, TB; and white stone bur, WB) and one control group were selected from 100 premolars (n = 20/group). The experimental teeth were bonded with a bracket, thermocycled, and debonded. Residual adhesive was removed by either of the respective methods. Pre and postdebonding root mean square (Rq) values were obtained from AFM evaluations. All specimens were examined and evaluated with SEM using a modified enamel surface index (modified ESI). Statistical Analysis Differences among the polishing methods were compared with analysis of variance and Fisher’s least significant difference test at p < 0.05. Results Both microscopic evaluations indicated that the surface with the greatest roughness herein belonged to the SD group, followed by that for SB, TB, and WB groups. AFM measurements indicated a maximum postdebonding Rq herein for the WB group and a significantly greater surface roughness for the TB and WB groups than for the SD and SB groups. Among the experimental groups, SEM followed by modified ESI evaluations revealed similar data to those obtained with AFM. Significant differences were seen among all paired groups, except for that between the SB and TB groups. Conclusion Within the limitations of this study, all four polishing methods were concluded to be clinically acceptable for removing residual orthodontic adhesives.


1972 ◽  
Vol 39 (3) ◽  
pp. 247-296 ◽  
Author(s):  
Tadao Kirino ◽  
Takashi Ichijo ◽  
Masatoshi Goto ◽  
Takeshi Ono ◽  
Yukishige Kozawa ◽  
...  

2016 ◽  
Vol 674 ◽  
pp. 189-194 ◽  
Author(s):  
Margarita A. Skotnikova ◽  
Galina V. Tsvetkova ◽  
Nikolay A. Krylov ◽  
Evgeniy K. Ivanov ◽  
Viktoriy V. Medvedeva ◽  
...  

In this article by the example of two abrasive materials from oxide of aluminum and nitride of boron, the processes developing in a thin surface layer between a grain of abrasive and the material, processed by microcutting with speeds of 40 and 160 m/s, the preforms from armko-iron, steels R18, 45, H18N10T and alloy titanium VT6 are investigated, using the scanning electron microscopy method.


1980 ◽  
Vol 1 ◽  
Author(s):  
L. Buene ◽  
E. N. Kaufmann ◽  
C. M. Preece ◽  
C. W. Draper

ABSTRACTLaser pulse melted single crystals of several metals have been examined by the Rutherford backscattering/channeling technique and with optical and scanning electron microscopy. Metals belonging to the three major structure groups; fcc (Ni, Pd, Rh); bcc(Mo, Nb, W, Fe); and hcp (Be, Ti, Re) have been studied at various laser power levels and in different crystallographic orientations. Of these cases, Be, Ti and Fe show high temperature allotropes which are expected to influence the character of the resolidified surface layer.


2011 ◽  
Vol 467-469 ◽  
pp. 1280-1284
Author(s):  
Jun Hui Yin ◽  
Jian Zheng ◽  
Chang Zhi Jia ◽  
Ming Hui Ye

As a special hot-work progress, artillery shooting test was put in practice, and rotating band specimen of Cu-4 Mass%Zn alloy was prepared. The mesostructure and microstructure evolution of the alloy under instantaneous extrusion and high speed friction were observed by optical microscopy (OM) and scanning electron microscopy (SEM). Severe plastic deformation (SPD) and dynamic recrystallization phenomena were researched. The analysis results are as follows. At the beginning of SPD, under the instantaneous compression, the surface layer of alloy became fibrous tissue with the phenomena of work-hardening. With the plastic deformation continue, temperature of alloy arising rapidly under the high speed friction. Recrystallization occurs within the outermost part of fibrous tissue due to heating, so subgrains gradually become homogeneous equiaxed grains. In addition, SPD has little effect on the inner tissue, which is full of equiaxed grains still. Between equiaxed grains and fibrous tissue, there are many oblique strip grains which formed by radial extrusion stress , tangential slip stress and axial sliding stress .


2015 ◽  
Vol 21 (5) ◽  
pp. 1264-1270 ◽  
Author(s):  
Manila Chieruzzi ◽  
Stefano Pagano ◽  
Carlo De Carolis ◽  
Stefano Eramo ◽  
José M. Kenny

AbstractThe inflammatory resorption of dental root apex (i.e., the process of removal of cementum and/or dentine through the activity of resorbing cells) may show different configurations and damage the apical root structure. As knowing the morphology of resorption areas of human teeth is essential for the success of endodontic treatments, we investigated the apical resorption by scanning electron microscopy, focusing on roots with granulomas. A total of 30 teeth (with penetrating carious lesions and chronic periapical lesions) were examined, the apical third of the roots were removed and analyzed to estimate periforaminal and foraminal resorption, shape and morphology of foramen resorption, centering of the periforaminal resorption area, and diameters of each apical foramen. Periforaminal resorption was present in all samples, whereas foraminal resorption was present in 92% of cases (mainly funnel shaped). Lacunae were observed in the foraminal resorption area with an average diameter of 35±14 μm. The major and minor diameters of the foramina in teeth with resorption were 443 and 313 μm, respectively (higher than in healthy teeth). This result indicates an expansion of the apical diameters caused by the pathology, which could encourage a different clinical instrumentation for these teeth.


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