Enamel Deproteinization using Papacarie and 10% Papain Gel on Shear Bond Strength of Orthodontic Brackets Before and After Acid Etching.

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Agarwal, R M; Yeluri, R; Singh, C; Munshi, A K

2015-01-01

To suggest Papacarie(®) as a new deproteinizing agent in comparison with indigenously prepared 10% papain gel before and after acid etching that may enhance the quality of the bond between enamel surface and composite resin complex. One hundred and twenty five extracted human premolars were utilized and divided into five groups: In the group 1, enamel surface was etched and primer was applied. In group 2, treatment with papacarie(®) for 60 seconds followed by etching and primer application. In group 3, etching followed by treatment with papacarie(®) for 60 seconds and primer application. In group 4, treatment with 10% papain gel for 60 seconds followed by etching and primer application. In group 5, etching followed by treatment with 10% papain gel for 60 seconds and primer application . After bonding the brackets, the mechanical testing was performed using a Universal testing machine. The failure mode was analyzed using an adhesive remnant index. The etching patterns before and after application of papacarie(®) and 10% papain gel was also evaluated using SEM. The values obtained for shear bond strength were submitted to analysis of variance and Tukey test (p Adhesive remnant index no statistical difference was seen between the groups (p=0.538). Papacarie(®) or 10% papain gel can be used to deproteinize the enamel surface before acid etching to enhance the bond strength of orthodontic brackets.

Shear bond strength of one-step self-etch adhesives to enamel: effect of acid pretreatment.

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Poggio, Claudio; Scribante, Andrea; Della Zoppa, Federica; Colombo, Marco; Beltrami, Riccardo; Chiesa, Marco

2014-02-01

The purposes of this study were to evaluate the effect of surface pretreatment with phosphoric acid on the enamel bond strength of four-one-step self-etch adhesives with different pH values. One hundred bovine permanent mandibular incisors were used. The materials used in this study included four-one-step self-etch adhesives with different pH values: Adper(™) Easy Bond Self-Etch Adhesive (ph = 0,8-1), Futurabond NR (ph = 1,4), G-aenial Bond (ph = 1,5), Clearfil(3) S Bond (ph = 2,7). One two-step self-etch adhesive (Clearfil SE Bond/ph = 0,8-1) was used as control. The teeth were assigned into two subgroups according to bonding procedure. In the first subgroup (n = 50), no pretreatment agent was applied. In the second subgroup (n = 50), etching was performed using 37% phosphoric acid for 30 s. After adhesive systems application, a nanohybrid composite resin was inserted into the enamel surface. The specimens were placed in a universal testing machine (Model 3343, Instron Corp., Canton, Mass., USA). After the testing procedure, the fractured surfaces were examined with an optical microscope at a magnification of 10× to determine failure modes. The adhesive remnant index (ARI) was used to assess the amount of adhesive left on the enamel surface. Descriptive statistics of the shear bond strength and frequency distribution of ARI scores were calculated. Enamel pretreatment with phosphoric acid significantly increased bond strength values of all the adhesives tested. No significant differences in bond strength were detected among the four different one-step self-etch adhesives with different pH. Two-step self-etch adhesive showed the highest bond strength. © 2013 John Wiley & Sons A/S.

Bond strength and morphology of enamel using self-etching adhesive systems with different acidities

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Sandra Kiss Moura

2009-08-01

Full Text Available OBJECTIVES: To assess the bond strength and the morphology of enamel after application of self-etching adhesive systems with different acidities. The tested hypothesis was that the performance of the self-etching adhesive systems does not vary for the studied parameters. MATERIAL AND METHODS: Composite resin (Filtek Z250 buildups were bonded to untreated (prophylaxis and treated (bur-cut or SiC-paper enamel surfaces of third molars after application of four self-etching and two etch-and-rinse adhesive systems (n=6/condition: Clearfil SE Bond (CSE; OptiBond Solo Plus Self-Etch (OP; AdheSe (AD; Tyrian Self Priming Etching (TY, Adper Scotchbond Multi-Purpose Plus (SBMP and Adper Single Bond (SB. After storage in water (24 h/37°C, the bonded specimens were sectioned into sticks with 0.8 mm² cross-sectional area and the microtensile bond strength was tested at a crosshead speed of 0.5 mm/min. The mean bond strength values (MPa were subjected to two-way ANOVA and Tukey's test (α=0.05. The etching patterns of the adhesive systems were also observed with a scanning electron microscope. RESULTS: The main factor adhesive system was statistically significant (p<0.05. The mean bond strength values (MPa and standard deviations were: CSE (20.5±3.5, OP (11.3±2.3, AD (11.2±2.8, TY (11.1±3.0, SBMP (21.9±4.0 and SB (24.9±3.0. Different etching patterns were observed for the self-etching primers depending on the enamel treatment and the pH of the adhesive system. CONCLUSION: Although there is a tendency towards using adhesive systems with simplified application procedures, this may compromise the bonding performance of some systems to enamel, even when the prismless enamel is removed.

Influence of laser etching on enamel and dentin bond strength of Silorane System Adhesive.

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Ustunkol, Ildem; Yazici, A Ruya; Gorucu, Jale; Dayangac, Berrin

2015-02-01

The aim of this in vitro study was to evaluate the shear bond strength (SBS) of Silorane System Adhesive to enamel and dentin surfaces that had been etched with different procedures. Ninety freshly extracted human third molars were used for the study. After the teeth were embedded with buccal surfaces facing up, they were randomly divided into two groups. In group I, specimens were polished with a 600-grit silicon carbide (SiC) paper to obtain flat exposed enamel. In group II, the overlying enamel layer was removed and exposed dentin surfaces were polished with a 600-grit SiC paper. Then, the teeth in each group were randomly divided into three subgroups according to etching procedures: etched with erbium, chromium:yttrium-scandium-gallium-garnet laser (a), etched with 35% phosphoric acid (b), and non-etched (c, control). Silorane System Adhesive was used to bond silorane restorative to both enamel and dentin. After 24-h storage in distilled water at room temperature, a SBS test was performed using a universal testing machine at a crosshead speed of 1 mm/min. The data were analyzed using two-way ANOVA and Bonferroni tests (p enamel and dentin (p > 0.05). The SBS of self-etch adhesive to dentin was not statistically different from enamel (p > 0.05). Phosphoric acid treatment seems the most promising surface treatment for increasing the enamel and dentin bond strength of Silorane System Adhesive.

Characterization of the porosity of human dental enamel and shear bond strength in vitro after variable etch times: initial findings using the BET method.

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Nguyen, Trang T; Miller, Arthur; Orellana, Maria F

2011-07-01

(1) To quantitatively characterize human enamel porosity and surface area in vitro before and after etching for variable etching times; and (2) to evaluate shear bond strength after variable etching times. Specifically, our goal was to identify the presence of any correlation between enamel porosity and shear bond strength. Pore surface area, pore volume, and pore size of enamel from extracted human teeth were analyzed by Brunauer-Emmett-Teller (BET) gas adsorption before and after etching for 15, 30, and 60 seconds with 37% phosphoric acid. Orthodontic brackets were bonded with Transbond to the samples with variable etch times and were subsequently applied to a single-plane lap shear testing system. Pore volume and surface area increased after etching for 15 and 30 seconds. At 60 seconds, this increase was less pronounced. On the contrary, pore size appears to decrease after etching. No correlation was found between variable etching times and shear strength. Samples etched for 15, 30, and 60 seconds all demonstrated clinically viable shear strength values. The BET adsorption method could be a valuable tool in enhancing our understanding of enamel characteristics. Our findings indicate that distinct quantitative changes in enamel pore architecture are evident after etching. Further testing with a larger sample size would have to be carried out for more definitive conclusions to be made.

Selective Acid Etching Improves the Bond Strength of Universal Adhesive to Sound and Demineralized Enamel of Primary Teeth.

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Antoniazzi, Bruna Feltrin; Nicoloso, Gabriel Ferreira; Lenzi, Tathiane Larissa; Soares, Fabio Zovico Maxnuck; Rocha, Rachel de Oliveira

To evaluate the influence of enamel condition and etching strategy on bond strength of a universal adhesive in primary teeth. Thirty-six primary molars were randomly assigned to six groups (n = 6) according to the enamel condition (sound [S] and demineralized [DEM]/cariogenic challenge by pH cycling prior to restorative procedures) and adhesive system (Scotchbond Universal Adhesive [SBU]) used in either etch-and-rinse (ER) or selfetching (SE) mode, with Clearfil SE Bond as the self-etching control. The adhesives were applied to flat enamel surfaces and composite cylinders (0.72 mm2) were built up. After 24-h storage in water, specimens were subjected to the microshear test. Bond strength (MPa) data were analyzed using two-way ANOVA and Tukey's post-hoc tests (α = 0.05). Significant differences were found considering the factors adhesive system (p = 0.003) and enamel condition (p = 0.001). Demineralized enamel negatively affected the bond strength, with μSBS values approximately 50% lower than those obtained for sound enamel. SBU performed better in etch-and-rinse mode, and the bond strength found for SBU applied in self-etching mode was similar to that of CSE. Enamel etching with phosphoric acid improves the bond strength of a universal adhesive system to primary enamel. Demineralized primary enamel results in lower bond strength.

Femtosecond laser etching of dental enamel for bracket bonding.

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Kabas, Ayse Sena; Ersoy, Tansu; Gülsoy, Murat; Akturk, Selcuk

2013-09-01

The aim is to investigate femtosecond laser ablation as an alternative method for enamel etching used before bonding orthodontic brackets. A focused laser beam is scanned over enamel within the area of bonding in a saw tooth pattern with a varying number of lines. After patterning, ceramic brackets are bonded and bonding quality of the proposed technique is measured by a universal testing machine. The results are compared to the conventional acid etching method. Results show that bonding strength is a function of laser average power and the density of the ablated lines. Intrapulpal temperature changes are also recorded and observed minimal effects are observed. Enamel surface of the samples is investigated microscopically and no signs of damage or cracking are observed. In conclusion, femtosecond laser exposure on enamel surface yields controllable patterns that provide efficient bonding strength with less removal of dental tissue than conventional acid-etching technique.

Comparative evaluation of self-etching primers and phosphoric acid effectiveness on composite to enamel bond: an in vitro study.

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Patil, Basanagouda S; Rao, Bk Raghavendra; Sharathchandra, Sm; Hegde, Reshma; Kumar, G Vinay

2013-09-01

The aim of the present study was to investigate the effectiveness of the one total-etch self-priming adhesive, one two-step self-etching primer adhesive, and one 'all-in-one' self-etching adhesive system on the adhesion of a resin composite to enamel. Thirty-six freshly extracted human mandibular molars were selected for this study. A fat area about 5 mm in diameter was created on the exposed mesial surface of enamel of each tooth by moist grinding with 320, 420 and 600 grit silicon carbide paper. Twelve teeth were randomly assigned into three groups. In group 1, Adper Easy One (3M ESPE), a one step self-etching primer adhesive was applied and light curing unit for 10 seconds. In group 2, Adper SE Plus, a two-step self-etching primer with bottle A containing the aqueous primer and bottle B containing the acidic adhesive was applied and light cured for 10 seconds. Group 3 (control)-etchant 37% phosphoric acid is applied to the surface for 15 seconds and rinsed with water and air dried and adhesive (single bond 2) is applied to the surface and tube is placed and light cured for 20 seconds. Composite material (Z350) was placed in the tube and light cured for 40 seconds in all the groups. Bond strength testing was done using universal testing machine at the enamel-composite interface. The debonded enamel surface was evaluated in stereomicroscope to assess the cohesive, adhesive or mixed fracture. Data was statistically analyzed by one way analysis of variance (ANOVA). Group 1 performed least among all groups with a mean score of 19.46 MPa. Group 2 had a mean score of 25.67 MPa. Group 3 had a mean score of 27.16 MPa. Under the conditions of this in vitro study, the bond strength values of the two-step self-etching primer systems tested were similar to the total-etch. And, one step self-etching primers have lower bond strength compared to the total-etch.

Two-year Randomized Clinical Trial of Self-etching Adhesives and Selective Enamel Etching.

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Pena, C E; Rodrigues, J A; Ely, C; Giannini, M; Reis, A F

2016-01-01

The aim of this randomized, controlled prospective clinical trial was to evaluate the clinical effectiveness of restoring noncarious cervical lesions with two self-etching adhesive systems applied with or without selective enamel etching. A one-step self-etching adhesive (Xeno V(+)) and a two-step self-etching system (Clearfil SE Bond) were used. The effectiveness of phosphoric acid selective etching of enamel margins was also evaluated. Fifty-six cavities were restored with each adhesive system and divided into two subgroups (n=28; etch and non-etch). All 112 cavities were restored with the nanohybrid composite Esthet.X HD. The clinical effectiveness of restorations was recorded in terms of retention, marginal integrity, marginal staining, caries recurrence, and postoperative sensitivity after 3, 6, 12, 18, and 24 months (modified United States Public Health Service). The Friedman test detected significant differences only after 18 months for marginal staining in the groups Clearfil SE non-etch (p=0.009) and Xeno V(+) etch (p=0.004). One restoration was lost during the trial (Xeno V(+) etch; p>0.05). Although an increase in marginal staining was recorded for groups Clearfil SE non-etch and Xeno V(+) etch, the clinical effectiveness of restorations was considered acceptable for the single-step and two-step self-etching systems with or without selective enamel etching in this 24-month clinical trial.

Enamel and dentin bond strengths of a new self-etch adhesive system.

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Walter, Ricardo; Swift, Edward J; Boushell, Lee W; Braswell, Krista

2011-12-01

statement of problem:  Self-etch adhesives typically are mildly acidic and therefore less effective than etch-and-rinse adhesives for bonding to enamel.   The purpose of this study was to evaluate the enamel and dentin shear bond strengths of a new two-step self-etch adhesive system, OptiBond XTR (Kerr Corporation, Orange, CA, USA).   The labial surfaces of 80 bovine teeth were ground to create flat, 600-grit enamel or dentin surfaces. Composite was bonded to enamel or dentin using the new two-step self-etch system or a three-step etch-and-rinse (OptiBond FL, Kerr), two-step self-etch (Clearfil SE Bond, Kuraray America, Houston, TX, USA), or one-step self-etch adhesive (Xeno IV, Dentsply Caulk, Milford, DE, USA). Following storage in water for 24 hours, shear bond strengths were determined using a universal testing machine. The enamel and dentin data sets were subjected to separate analysis of variance and Tukey's tests. Scanning electron microscopy was used to evaluate the effects of each system on enamel.   Mean shear bond strengths to enamel ranged from 18.1 MPa for Xeno IV to 41.0 MPa for OptiBond FL. On dentin, the means ranged from 33.3 MPa for OptiBond FL to 47.1 MPa for Clearfil SE Bond. OptiBond XTR performed as well as Clearfil SE Bond on dentin and as well as OptiBond FL on enamel. Field emission scanning electron microscope revealed that OptiBond XTR produced an enamel etch pattern that was less defined than that of OptiBond FL (37.5% phosphoric acid) but more defined than that of Clearfil SE Bond or Xeno IV.   The new two-step self-etch adhesive system formed excellent bonds to enamel and dentin in vitro. OptiBond XTR, a new two-step self-etch adhesive system, is a promising material for bonding to enamel as well as to dentin. © 2011 Wiley Periodicals, Inc.

Etching of enamel for direct bonding with a thulium fiber laser

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Kabaş Sarp, Ayşe S.; Gülsoy, Murat

2011-03-01

Background: Laser etching of enamel for direct bonding can decrease the risk of surface enamel loss and demineralization which are the adverse effects of acid etching technique. However, in excess of +5.5°C can cause irreversible pulpal responses. In this study, a 1940- nm Thulium Fiber Laser in CW mode was used for laser etching. Aim: Determination of the suitable Laser parameters of enamel surface etching for direct bonding of ceramic brackets and keeping that intrapulpal temperature changes below the threshold value. Material and Method: Polycrystalline ceramic orthodontic brackets were bonded on bovine teeth by using 2 different kinds of etching techniques: Acid and Laser Etching. In addition to these 3 etched groups, there was also a group which was bonded without etching. Brackets were debonded with a material testing machine. Breaking time and the load at the breaking point were measured. Intrapulpal temperature changes were recorded by a K-type Thermocouple. For all laser groups, intrapulpal temperature rise was below the threshold value of 5.5°C. Results and Conclusion: Acid-etched group ( 11.73 MPa) significantly required more debonding force than 3- second- irradiated ( 5.03 MPa) and non-etched groups ( 3.4 MPa) but the results of acid etched group and 4- second- irradiated group (7.5 MPa) showed no significant difference. Moreover, 4- second irradiated group was over the minimum acceptable value for clinical use. Also, 3- second lasing caused a significant reduction in time according to acid-etch group. As a result, 1940- nm laser irradiation is a promising method for laser etching.

Effect of Phosphoric Acid Pre-etching on Fatigue Limits of Self-etching Adhesives.

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Takamizawa, T; Barkmeier, W W; Tsujimoto, A; Scheidel, D D; Erickson, R L; Latta, M A; Miyazaki, M

2015-01-01

The purpose of this study was to use shear bond strength (SBS) and shear fatigue limit (SFL) testing to determine the effect of phosphoric acid pre-etching of enamel and dentin prior to application of self-etch adhesives for bonding resin composite to these substrates. Three self-etch adhesives--1) G- ænial Bond (GC Corporation, Tokyo, Japan); 2) OptiBond XTR (Kerr Corp, Orange, CA, USA); and 3) Scotchbond Universal (3M ESPE Dental Products, St Paul, MN, USA)--were used to bond Z100 Restorative resin composite to enamel and dentin surfaces. A stainless-steel metal ring with an inner diameter of 2.4 mm was used to bond the resin composite to flat-ground (4000 grit) tooth surfaces for determination of both SBS and SFL. Fifteen specimens each were used to determine initial SBS to human enamel/dentin, with and without pre-etching with a 35% phosphoric acid (Ultra-Etch, Ultradent Products Inc, South Jordan, UT, USA) for 15 seconds prior to the application of the adhesives. A staircase method of fatigue testing (25 specimens for each test) was then used to determine the SFL of resin composite bonded to enamel/dentin using a frequency of 10 Hz for 50,000 cycles or until failure occurred. A two-way analysis of variance and Tukey post hoc test were used for analysis of SBS data, and a modified t-test with Bonferroni correction was used for the SFL data. Scanning electron microscopy was used to examine the area of the bonded restorative/tooth interface. For all three adhesive systems, phosphoric acid pre-etching of enamel demonstrated significantly higher (padhesives clearly demonstrated different tendencies between enamel and dentin. The effect of using phosphoric acid, prior to the application of the self-etching adhesives, on SBS and SFL was dependent on the adhesive material and tooth substrate and should be carefully considered in clinical situations.

Acids with an equivalent taste lead to different erosion of human dental enamel.

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Beyer, Markus; Reichert, Jörg; Bossert, Jörg; Sigusch, Bernd W; Watts, David C; Jandt, Klaus D

2011-10-01

The consumption of acidic soft drinks may lead to demineralization and softening of human dental enamel, known as dental erosion. The aims of this in vitro study were to determine: (i) if different acids with a similar sensorial acidic taste lead to different hardness loss of enamel and (ii) if the fruit acids tartaric, malic, lactic or ascorbic acid lead to less hardness loss of enamel than citric or phosphoric acid when their concentration in solution is based on an equivalent sensorial acidic taste. Enamel samples of non-erupted human third molars were treated with acidic solutions of tartaric (TA), malic (MA), lactic (LA), ascorbic (AA), phosphoric (PA) and citric (CA) acids with a concentration that gave an equivalent sensorial acidic taste. The acidic solutions were characterized by pH value and titratable acidity. Atomic force microscopy (AFM) based nanoindentation was used to study the nano mechanical properties and scanning electron microscopy (SEM) was used to study the morphology of the treated enamel samples and the untreated control areas, respectively. The investigated acids fell into two groups. The nano hardnesses of MA, TA and CA treated enamel samples (group I) were statistically significantly greater (penamel samples (group II). Within each group the nano hardness was not statistically significantly different (p>0.05). The SEM micrographs showed different etch prism morphologies depending on the acid used. In vitro, the acids investigated led to different erosion effects on human dental enamel, despite their equivalent sensorial acidic taste. This has not been reported previously. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Histological structures and acidic etching sensitivities of the enamels at the occlusal pit parts in the deciduous and permanent teeth

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Takahashi, Masashi; Zheng, Jinhua; Mori, Kazuhisa; Mataga, Izumi; Kobayashi, Kan

2006-01-01

The purpose of this study is to compare the histological structures and acidic etching sensitivities of the enamels at the occlusal pit parts between the deciduous molars and permanent molars. They were observed by the polarizing and scanning electron microscopies. The enamel rods were less made slender by EDTA etching and the outlines of the apatite crystals, constituting the enamel rods, were clearer at the occlusal pit part of the deciduous molar than that of the permanent molar in reverse of that at the cusp part. It is thought that the enamel at the occlusal pit part of the permanent molar is more easily decayed by the dental caries than that of the deciduous molar because the former is more easily decayed by the acidic etching than the latter in reverse at the cusp part. It is considered that the thin superficialmost layer of the enamel at the occlusal pit part of the permanent molar has originally higher degree of resistance to the dental caries

Histological structures and acidic etching sensitivities of the enamels at the occlusal pit parts in the deciduous and permanent teeth

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Takahashi, Masashi [Department of Dental Hygiene, Nippon Dental University College at Niigata, Niigata 951-8580 (Japan)]. E-mail: masashi@ngt.ndu.ac.jp; Zheng, Jinhua [Department of Oral Anatomy, School of Dentistry at Niigata, Nippon Dental University, Niigata 951-8580 (Japan); Mori, Kazuhisa [Department of Oral Surgery, School of Dentistry at Niigata, Nippon Dental University, Niigata 951-8580 (Japan); Mataga, Izumi [Department of Oral Surgery, School of Dentistry at Niigata, Nippon Dental University, Niigata 951-8580 (Japan); Kobayashi, Kan [Department of Oral Anatomy, School of Dentistry at Niigata, Nippon Dental University, Niigata 951-8580 (Japan)

2006-05-15

The purpose of this study is to compare the histological structures and acidic etching sensitivities of the enamels at the occlusal pit parts between the deciduous molars and permanent molars. They were observed by the polarizing and scanning electron microscopies. The enamel rods were less made slender by EDTA etching and the outlines of the apatite crystals, constituting the enamel rods, were clearer at the occlusal pit part of the deciduous molar than that of the permanent molar in reverse of that at the cusp part. It is thought that the enamel at the occlusal pit part of the permanent molar is more easily decayed by the dental caries than that of the deciduous molar because the former is more easily decayed by the acidic etching than the latter in reverse at the cusp part. It is considered that the thin superficialmost layer of the enamel at the occlusal pit part of the permanent molar has originally higher degree of resistance to the dental caries.

The Effect of Phosphoric Acid Pre-etching Times on Bonding Performance and Surface Free Energy with Single-step Self-etch Adhesives.

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Tsujimoto, A; Barkmeier, W W; Takamizawa, T; Latta, M A; Miyazaki, M

2016-01-01

The purpose of this study was to evaluate the effect of phosphoric acid pre-etching times on shear bond strength (SBS) and surface free energy (SFE) with single-step self-etch adhesives. The three single-step self-etch adhesives used were: 1) Scotchbond Universal Adhesive (3M ESPE), 2) Clearfil tri-S Bond (Kuraray Noritake Dental), and 3) G-Bond Plus (GC). Two no pre-etching groups, 1) untreated enamel and 2) enamel surfaces after ultrasonic cleaning with distilled water for 30 seconds to remove the smear layer, were prepared. There were four pre-etching groups: 1) enamel surfaces were pre-etched with phosphoric acid (Etchant, 3M ESPE) for 3 seconds, 2) enamel surfaces were pre-etched for 5 seconds, 3) enamel surfaces were pre-etched for 10 seconds, and 4) enamel surfaces were pre-etched for 15 seconds. Resin composite was bonded to the treated enamel surface to determine SBS. The SFEs of treated enamel surfaces were determined by measuring the contact angles of three test liquids. Scanning electron microscopy was used to examine the enamel surfaces and enamel-adhesive interface. The specimens with phosphoric acid pre-etching showed significantly higher SBS and SFEs than the specimens without phosphoric acid pre-etching regardless of the adhesive system used. SBS and SFEs did not increase for phosphoric acid pre-etching times over 3 seconds. There were no significant differences in SBS and SFEs between the specimens with and without a smear layer. The data suggest that phosphoric acid pre-etching of ground enamel improves the bonding performance of single-step self-etch adhesives, but these bonding properties do not increase for phosphoric acid pre-etching times over 3 seconds.

Laser etching of enamel for direct bonding - An in vitro study

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Rajesh K Reddy

2010-01-01

Full Text Available The aim of the study was to determine the shear bond strength of mesh shaped stainless steel orthodontic brackets, bonded to acid etched enamel and laser etched enamel and to compare the shear bond strength following acid etching and laser etching. 50 non carious extracted premolar teeth divided in to 5 groups of 10 each were employed in the study. The buccal surfaces of group - I were subjected to conventional etching using 37% phosphoric acid for 30 seconds, while the other four groups were subjected to Nd:YAG laser etching at different power settings of 80mj, 100mj, 150mj and 200mj respectively for 15 seconds. Brackets were later bonded on to these teeth using Ultimate- light curing primer and adhesive. The shear bond strength of each sample was determined using a universal testing machine and the results were evaluated.

Crystal growth vs. conventional acid etching: A comparative evaluation of etch patterns, penetration depths, and bond strengths

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Devanna Raghu

2008-01-01

Full Text Available The present study was undertaken to investigate the effect on enamel surface, penetration depth, and bond strength produced by 37% phosphoric acid and 20% sulfated polyacrylic acid as etching agents for direct bonding. Eighty teeth were used to study the efficacy of the etching agents on the enamel surface, penetration depth, and tensile bond strength. It was determined from the present study that a 30 sec application of 20% sulfated polyacrylic acid produced comparable etching topography with that of 37% phosphoric acid applied for 30 sec. The 37% phosphoric acid dissolves enamel to a greater extent than does the 20% sulfated polyacrylic acid. Instron Universal testing machine was used to evaluate the bond strengths of the two etching agents. Twenty percent sulfated polyacrylic acid provided adequate tensile bond strength. It was ascertained that crystal growth can be an alternative to conventional phosphoric acid etching as it dissolves lesser enamel and provides adequate tensile bond strength.

Comparison of shear bond strength of universal adhesives on etched and nonetched enamel.

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Beltrami, Riccardo; Chiesa, Marco; Scribante, Andrea; Allegretti, Jessica; Poggio, Claudio

2016-04-06

The purpose of this study was to evaluate the effect of surface pretreatment with 37% phosphoric acid on the enamel bond strength of different universal adhesives. One hundred and sixty bovine permanent mandibular incisors freshly extracted were used as a substitute for human teeth. The materials tested in this study included 6 universal adhesives, and 2 self-etch adhesives as control. The teeth were assigned into 2 groups: In the first group, etching was performed using 37% phosphoric acid for 30 seconds. In the second group, no pretreatment agent was applied. After adhesive application, a nanohybrid composite resin was inserted into the enamel surface by packing the material into cylindrical-shaped plastic matrices. After storing, the specimens were placed in a universal testing machine. The normality of the data was calculated using the Kolmogorov-Smirnov test. Analysis of variance (ANOVA) was applied to determine whether significant differences in debond strength values existed among the various groups. Groups with phosphoric acid pretreatment showed significantly higher shear bond strength values than groups with no enamel pretreatment (p<0.001). No significant variation in shear strength values was detected when comparing the different adhesive systems applied onto enamel after orthophosphoric acid application (p>0.05). All adhesives provide similar bond strength values when enamel pretreatment is applied even if compositions are different. Bond strength values are lower than promised by manufacturers.

Comparison of Shear Bond Strength of Orthodontic Brackets Bonded to Enamel Prepared By Er:YAG Laser and Conventional Acid-Etching

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Hosseini, M.H.; Namvar, F.; Chalipa, J.; Saber, K.; Chiniforush, N.; Sarmadi, S.; Mirhashemi, A.H.

2012-01-01

Introduction: The purpose of this study was to compare shear bond strength (SBS) of orthodontic brackets bonded to enamel prepared by Er:YAG laser with two different powers and conventional acid-etching. Materials and Methods: Forty-five human premolars extracted for orthodontic purposes were randomly assigned to three groups based on conditioning method: Group 1- conventional etching with 37% phosphoric acid; Group 2- irradiation with Er:YAG laser at 1 W; and Group 3- irradiation with Er:YAG laser at 1.5 W. Metal brackets were bonded on prepared enamel using a light-cured composite. All groups were subjected to thermocycling process. Then, the specimens mounted in auto-cure acryle and shear bond strength were measured using a universal testing machine with a crosshead speed of 0.5 mm per second. After debonding, the amount of resin remaining on the teeth was determined using the adhesive remnant index (ARI) scored 1 to 5. One-way analysis of variance was used to compare shear bond strengths and the Kruskal-Wallis test was performed to evaluate differences in the ARI for different etching types. Results: The mean and standard deviation of conventional acid-etch group, 1W laser group and 1.5W laser group was 3.82 ± 1.16, 6.97 ± 3.64 and 6.93 ± 4.87, respectively. Conclusion: The mean SBS obtained with an Er:YAG laser operated at 1W or 1.5W is approximately similar to that of conventional etching. However, the high variability of values in bond strength of irradiated enamel should be considered to find the appropriate parameters for applying Er:YAG laser as a favorable alternative for surface conditioning. PMID:22924098

Bonding efficacy of new self-etching, self-adhesive dual-curing resin cements to dental enamel.

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Benetti, Paula; Fernandes, Virgílio Vilas; Torres, Carlos Rocha; Pagani, Clovis

2011-06-01

This study evaluated the efficacy of the union between two new self-etching self-adhesive resin cements and enamel using the microtensile bond strength test. Buccal enamel of 80 bovine teeth was submitted to finishing and polishing with metallographic paper to a refinement of #600, in order to obtain a 5-mm2 flat area. Blocks (2 x 4 x 4 mm) of laboratory composite resin were cemented to enamel according to different protocols: (1) untreated enamel + RelyX Unicem cement (RX group); (2) untreated enamel + Bifix SE cement (BF group); (3) enamel acid etching and application of resin adhesive Single Bond + RelyX Unicem (RXA group); (4) enamel acid etching and application of resin adhesive Solobond M + Bifix SE (BFA group). After 7 days of storage in distillated water at 37°C, the blocks were sectioned for obtaining microbar specimens with an adhesive area of 1 mm2 (n = 120). Specimens were submitted to the microtensile bond strength test at a crosshead speed of 0.5 mm/min. The results (in MPa) were analyzed statistically by ANOVA and Tukey's test. Enamel pre-treatment with phosphoric acid and resin adhesive (27.9 and 30.3 for RXA and BFA groups) significantly improved (p ≤ 0.05) the adhesion of both cements to enamel compared to the union achieved with as-polished enamel (9.9 and 6.0 for RX and BF). Enamel pre-treatment with acid etching and the application of resin adhesive significantly improved the bond efficacy of both luting agents compared to the union achieved with as-polished enamel.

Comparison Of Bond Strength Of Orthodontic Molar Tubes Using Different Enamel Etching Techniques And Their Effect On Enamel

International Nuclear Information System (INIS)

Abd el Rahman, H.Y.

2013-01-01

In fixed orthodontic treatment, brackets and tubes are used for transferring orthodontic forces to the teeth. Those attachments were welded to cemented bands. Fifty years ago, direct bonding of brackets and other attachments has become a common technique in fixed orthodontic treatment. Orthodontists used to band teeth, especially molars and second premolars, to avoid the need for re bonding accessories in these regions of heavy masticatory forces. However, it is a known fact that direct bonding saves chair time as it does not require prior band selection and fitting, has the ability to maintain good oral hygiene, improve esthetics and make easier attachment to crowded and partially erupted teeth. Moreover, when the banding procedure is not performed with utmost care it can damage periodontal and/or dental tissues. Molar tubes bonding decreases the chance of decalcification caused by leakage beneath the bands. Since molar teeth are subjected to higher masticatory impact, especially lower molars, it would be convenient to devise methods capable of increasing the efficiency of their traditional bonding. These methods may include variation in bond able molar tube material, design, bonding materials and etching techniques. For achieving successful bonding, the bonding agent must penetrate the enamel surface; have easy clinical use, dimensional stability and enough bond strength. Different etching techniques were introduced in literature to increase the bond strength which includes: conventional acid etching, sandblasting and laser etching techniques. The process of conventional acid etching technique was invented In (1955) as the surface of enamel has great potential for bonding by micromechanical retention, to form ‘the mechanical lock‘. The primary effect of enamel etching is to increase the surface area. However, this roughens the enamel microscopically and results in a greater surface area on which to bond. By dissolving minerals in enamel, etchants remove the

Effect of pre-etching on sealing ability of two current self-etching adhesives

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K Khosravi

2005-05-01

Full Text Available Background: We evaluated the effect of phosphoric acid etching on microleakage of two current self-etching adhesives on enamel margins in comparison to a conventional total- etch system. Methods: Sixty buccal class V cavities were made at the cemento-enamel junction with beveled enamel margins of extracted human premolar teeth and randomly divided into five groups (12 specimens in each group. Group 1 was applying with Clearfil SE bond, Group 2 with 35% phosphoric acid etching of enamel margins plus Clearfil SE bond, Group3 with I bond, Group 4 with 35% phosphoric acid etching of enamel margins plus I bond and Group5 with Scotchbond multi-purpose. All groups restored with a composite resins. After 24 hours storage with 100% humidity, the samples were thermocycled, immersed in a dye solution and sectioned buccoligually and enamel margins microleakage were evaluated on a scale of 0 to 2. Results: The differences between Groups 1 & 3 and Groups 3 & 4 were significant (P<0.05 but no significant differences between Groups1 & 2 or 1 & 5 were observed. Conclusion: The findings suggest that all-in-one adhesive systems need pre-etching enamel margins with phosphoric acid for effectively seal. Key words: Self-Etching Adhesives, Microleakage, Enamel, Total-Etch system

Performance of a new one-step multi-mode adhesive on etched vs non-etched enamel on bond strength and interfacial morphology.

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de Goes, Mario Fernando; Shinohara, Mirela Sanae; Freitas, Marcela Santiago

2014-06-01

To compare microtensile bond strength (μTBS) and interfacial morphology of a new one-step multimode adhesive with a two-step self-etching adhesive and two etch-and-rinse adhesives systems on enamel. Thirty human third molars were sectioned to obtain two enamel fragments. For μTBS, 48 enamel surfaces were ground using 600-grit SiC paper and randomly assigned into 6 groups (n = 8): nonetched Scotchbond Universal [SBU]; etched SBU [SBU-et]; non-etched Clearfil SE Bond [CSE]; etched CSE [CSE-et]; Scotchbond Multi-PURPOSE [SBMP]; Excite [EX]. The etched specimens were conditioned with 37% phosphoric acid for 30 s, each adhesive system was applied according to manufacturers' instructions, and composite resin blocks (Filtek Supreme Plus, 3M ESPE) were incrementally built up. Specimens were sectioned into beams with a cross-sectional area of 0.8-mm2 and tested under tension (1 mm/min). The data were analyzed with oneway ANOVA and Fisher's PLSD (α = 0.05). For interface analysis, two samples from each group were embedded in epoxy resin, polished, and then observed using scanning electron microscopy (SEM). The μTBS values (in MPa) and the standard deviations were: SBU = 27.4 (8.5); SBU-et = 33.6 (9.3); CSE = 28.5 (8.3); CSE-et = 34.2 (9.0); SBMP = 30.4 (11.0); EX = 23.3 (8.2). CSE-et and SBU-et presented the highest bond strength values, followed by SBMP, CSE, and SBU which did not differ significantly from each other. EX showed the statistically significantly lowest bond strength values. SEM images of interfaces from etched samples showed long adhesive-resin tags penetrating into demineralized enamel. Preliminary etching of enamel significantly increased bond strength for the new one-step multimode adhesive SBU and two-step self-etching adhesive CSE.

Comparison of Shear Bond Strength of Orthodontic Brackets Bonded to Enamel Prepared By Er:YAG Laser and Conven-tional Acid-Etching

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M.H. Hosseini

2012-01-01

Full Text Available Introduction: The purpose of this study was to compare shear bond strength (SBS of orthodontic brackets bonded to enamel prepared by Er:YAG laser with two different powers and conventional acid-etching.Materials and Methods: Forty-five human premolars extracted for orthodontic purposes were randomly assigned to three groups based on conditioning method: Group 1- conventional etching with 37% phosphoric acid; Group 2- irradiation with Er:YAG laser at 1 W; and Group 3- irradiation with Er:YAG laser at 1.5 W. Metal brackets were bonded on prepared enamel using a light-cured composite. All groups were subjected to thermocycling process. Then, the specimens mounted in auto-cure acryle and shear bond strength were measured using a universal testing machine with a crosshead speed of 0.5 mm per second. After debonding, the amount of resin remaining on the teeth was determined using the adhesive remnant index (ARI scored 1 to 5. One-way analysis of variance was used to compare shear bond strengths and the Kruskal-Wallis test was performed to evaluate differences in the ARI for different etching types.Results: The mean and standard deviation of conventional acid-etch group, 1W laser group and 1.5W laser group was 3.82 ± 1.16, 6.97 ± 3.64 and 6.93 ± 4.87, respectively.Conclusion: The mean SBS obtained with an Er:YAG laser operated at 1W or 1.5W is approximately similar to that of conventional etching. However, the high variability of values in bond strength of irradiated enamel should be considered to find the appropriate parameters for applying Er:YAG laser as a favorable alternative for surface conditioning.

Influence of Etching Mode on Enamel Bond Durability of Universal Adhesive Systems.

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Suzuki, T; Takamizawa, T; Barkmeier, W W; Tsujimoto, A; Endo, H; Erickson, R L; Latta, M A; Miyazaki, M

2016-01-01

The purpose of this study was to determine the enamel bond durability of three universal adhesives in different etching modes through fatigue testing. The three universal adhesives used were Scotchbond Universal, Prime&Bond Elect universal dental adhesive, and All-Bond Universal light-cured dental adhesive. A single-step self-etch adhesive, Clearfil S 3 Bond Plus was used as a control. The shear bond strength (SBS) and shear fatigue strength (SFS) to human enamel were evaluated in total-etch mode and self-etch mode. A stainless steel metal ring with an internal diameter of 2.4 mm was used to bond the resin composite to the flat-ground (4000-grit) tooth surfaces for determination of both SBS and SFS. For each enamel surface treatment, 15 specimens were prepared for SBS and 30 specimens for SFS. The staircase method for fatigue testing was then used to determine the SFS of the resin composite bonded to the enamel using 10-Hz frequencies for 50,000 cycles or until failure occurred. Scanning electron microscopy was used to observe representative debonded specimen surfaces and the resin-enamel interfaces. A two-way analysis of variance and the Tukey post hoc test were used for analysis of the SBS data, whereas a modified t-test with Bonferroni correction was used for the SFS data. All adhesives in total-etch mode showed significantly higher SBS and SFS values than those in self-etch mode. Although All-Bond Universal in self-etch mode showed a significantly lower SBS value than the other adhesives, there was no significant difference in SFS values among the adhesives in this mode. All adhesives showed higher SFS:SBS ratios in total-etch mode than in self-etch mode. With regard to the adhesive systems used in this study, universal adhesives showed higher enamel bond strengths in total-etch mode. Although the influence of different etching modes on the enamel-bonding performance of universal adhesives was found to be dependent on the adhesive material, total-etch mode

Comparison of Self-Etch Primers with Conventional Acid Etching System on Orthodontic Brackets

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Zope, Amit; Zope-Khalekar, Yogita; Chitko, Shrikant S.; Kerudi, Veerendra V.; Patil, Harshal Ashok; Jaltare, Pratik; Dolas, Siddhesh G

2016-01-01

Introduction The self-etching primer system consists of etchant and primer dispersed in a single unit. The etching and priming are merged as a single step leading to fewer stages in bonding procedure and reduction in the number of steps that also reduces the chance of introduction of error, resulting in saving time for the clinician. It also results in smaller extent of enamel decalcification. Aim To compare the Shear Bond Strength (SBS) of orthodontic bracket bonded with Self-Etch Primers (SEP) and conventional acid etching system and to study the surface appearance of teeth after debonding; etching with conventional acid etch and self-etch priming, using stereomicroscope. Materials and Methods Five Groups (n=20) were created randomly from a total of 100 extracted premolars. In a control Group A, etching of enamel was done with 37% phosphoric acid and bonding of stainless steel brackets with Transbond XT (3M Unitek, Monrovia, California). Enamel conditioning in left over four Groups was done with self-etching primers and adhesives as follows: Group B-Transbond Plus (3M Unitek), Group C Xeno V+ (Dentsply), Group D-G-Bond (GC), Group E-One-Coat (Coltene). The Adhesive Remnant Index (ARI) score was also evaluated. Additionally, the surface roughness using profilometer were observed. Results Mean SBS of Group A was 18.26±7.5MPa, Group B was 10.93±4.02MPa, Group C was 6.88±2.91MPa while of Group D was 7.78±4.13MPa and Group E was 10.39±5.22MPa respectively. In conventional group ARI scores shows that over half of the adhesive was remaining on the surface of tooth (score 1 to 3). In self-etching primer groups ARI scores show that there was no or minor amount of adhesive remaining on the surface of tooth (score 4 and 5). SEP produces a lesser surface roughness on the enamel than conventional etching. However, statistical analysis shows significant correlation (pbracket bonding after enamel conditioning with any of the SEPs tested. The SEPs used in Groups C (Xeno V

Bond strength of a pit-and-fissure sealant associated to etch-and-rinse and self-etching adhesive systems to saliva-contaminated enamel: individual vs. simultaneous light curing.

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Gomes-Silva, Jaciara Miranda; Torres, Carolina Paes; Contente, Marta Maria Martins Giamatei; Oliveira, Maria Angélica Hueb de Menezes; Palma-Dibb, Regina Guenka; Borsatto, Maria Cristina

2008-01-01

This study evaluated in vitro the shear bond strength (SBS) of a resin-based pit-and-fissure sealant [Fluroshield (F), Dentsply/Caulk] associated with either an etch-and-rinse [Adper Single Bond 2 (SB), 3M/ESPE] or a self-etching adhesive system [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] to saliva-contaminated enamel, comparing two curing protocols: individual light curing of the adhesive system and the sealant or simultaneous curing of both materials. Mesial and distal enamel surfaces from 45 sound third molars were randomly assigned to 6 groups (n=15), according to the bonding technique: I - F was applied to 37% phosphoric acid etched enamel. The other groups were contaminated with fresh human saliva (0.01 mL; 10 s) after acid etching: II - SB and F were light cured separately; III - SB and F were light cured together; IV - S3 and F were light cured separately; V - S3 and F were light cured simultaneously; VI - F was applied to saliva-contaminated, acid-etched enamel without an intermediate bonding agent layer. SBS was tested to failure in a universal testing machine at 0.5 mm/min. Data were analyzed by one-way ANOVA and Fisher's test (alpha=0.05).The debonded specimens were examined with a stereomicroscope to assess the failure modes. Three representative specimens from each group were observed under scanning electron microscopy for a qualitative analysis. Mean SBS in MPa were: I-12.28 (+/-4.29); II-8.57 (+/-3.19); III-7.97 (+/-2.16); IV-12.56 (+/-3.11); V-11.45 (+/-3.77); and VI-7.47 (+/-1.99). In conclusion, individual or simultaneous curing of the intermediate bonding agent layer and the resin sealant did not seem to affect bond strength to saliva-contaminated enamel. S3/F presented significantly higher SBS than the that of the groups treated with SB etch-and-rinse adhesive system and similar SBS to that of the control group, in which the sealant was applied under ideal dry, noncontaminated conditions.

[Evaluation of shear bond strengths of self-etching and total-etching dental adhesives to enamel and dentin].

Science.gov (United States)

Yu, Ling; Liu, Jing-Ming; Wang, Xiao-Yan; Gao, Xue-Jun

2009-03-01

To evaluate the shear bond strengths of four dental adhesives in vitro. The facial surfaces of 20 human maxillary incisors were prepared to expose fresh enamel and randomly divided into four groups, in each group 5 teeth were bonded with one adhesives: group A (Clearfil Protect Bond, self-etching two steps), group B (Adper( Prompt, self-etching one step), group C (SwissTEC SL Bond, total-etching two steps), group D (Single Bond, total-etching two steps). Shear bond strengths were determined using an universal testing machine after being stored in distilled water for 24 h at 37 degrees C. The bond strengths to enamel and dentin were (25.33 +/- 2.84) and (26.07 +/- 5.56) MPa in group A, (17.08 +/- 5.13) and (17.93 +/- 4.70) MPa in group B, (33.14 +/- 6.05) and (41.92 +/- 6.25) MPa in group C, (22.51 +/- 6.25) and (21.45 +/- 7.34) MPa in group D. Group C showed the highest and group B the lowest shear bond strength to enamel and dentin among the four groups. The two-step self-etching adhesive showed comparable shear bond strength to some of the total-etching adhesives and higher shear bond strength than one-step self-etching adhesive.

Does active application of universal adhesives to enamel in self-etch mode improve their performance?

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Loguercio, Alessandro D; Muñoz, Miguel Angel; Luque-Martinez, Issis; Hass, Viviane; Reis, Alessandra; Perdigão, Jorge

2015-09-01

To evaluate the effect of adhesion strategy on the enamel microshear bond strengths (μSBS), etching pattern, and in situ degree of conversion (DC) of seven universal adhesives. 84 extracted third molars were sectioned in four parts (buccal, lingual, proximal) and divided into 21 groups, according to the combination of the main factors adhesive (AdheSE Universal [ADU], All-Bond Universal [ABU], Clearfil Universal [CFU], Futurabond U [FBU], G-Bond Plus [GBP], Prime&Bond Elect (PBE), and Scotchbond Universal Adhesive [SBU]), and adhesion strategy (etch-and-rinse, active self-etch, and passive self-etch). Specimens were stored in water (37°C/24h) and tested at 1.0mm/min (μSBS). Enamel-resin interfaces were evaluated for DC using micro-Raman spectroscopy. The enamel-etching pattern was evaluated under a field-emission scanning electron microscope (direct and replica techniques). Data were analyzed with two-way ANOVA and Tukey's test (α=0.05). Active self-etch application increased μSBS and DC for five out of the seven universal adhesives when compared to passive application (padhesives in the etch-and-rinse strategy. A slight improvement in etching ability was observed in active self-etch application compared to that of passive self-etch application. Replicas of GBP and PBE applied in active self-etch mode displayed morphological features compatible with water droplets. The DC of GBP and PBE were not affected by the application/strategy mode. In light of the improved performance of universal adhesives when applied actively in SE mode, selective enamel etching with phosphoric acid may not be crucial for their adhesion to enamel. The active application of universal adhesives in self-etch mode may be a practical alternative to enamel etching in specific clinical situations. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Different Protocols in Preconditioning With EDTA in Sclerotic Dentin and Enamel Before Universal Adhesives Applied in Self-etch Mode.

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Martini, E C; Parreiras, S O; Gutierrez, M F; Loguercio, A D; Reis, A

The aim of this study was to investigate the effect of different protocols of 17% ethylene diamine tetra-acetic acid (EDTA) conditioning on the etching pattern and immediate bond strength of universal adhesives to enamel and sclerotic dentin. Forty bovine teeth with sclerotic dentin and 20 human third molars were randomly divided into eight groups resulting from the combination of the main factors surface treatment (none, two-minute EDTA conditioning manual application, 30-second EDTA manual application, 30-second EDTA sonic application) and adhesives systems (Scotchbond Universal Adhesive [SBU] and Prime & Bond Elect [PBE]). Resin-dentin and enamel-dentin bond specimens were prepared and tested under the microtensile bond strength (μTBS) and microshear bond strength (μSBS) tests, respectively. The etching pattern produced on the unground enamel and the sclerotic dentin surfaces under the different protocols and adhesive systems was evaluated under scanning electron microscopy. For enamel, only the main factor adhesive was significant (padhesives in the self-etch mode on sclerotic dentin, mainly when applied for 30 seconds with the aid of a sonic device. EDTA pretreatment also improves the retentive etching pattern of enamel, but it does not result in higher enamel bond strength.

Bond efficacy and interface morphology of self-etching adhesives to ground enamel.

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Abdalla, Ali I; El Zohairy, Ahmed A; Abdel Mohsen, Mohamed M; Feilzer, Albert J

2010-02-01

This study compared the microshear bond strengths to ground enamel of three one-step self-etching adhesive systems, a self-etching primer system and an etch-and-rinse adhesive system. Three self-etching adhesives, Futurabond DC (Voco), Clearfil S Tri Bond (Kuraray) and Hybrid bond (Sun-Medical), a self-etching primer, Clearfil SE Bond (Kuraray), and an etch-and-rinse system, Admira Bond (Voco), were selected. Thirty human molars were used. The root of each tooth was removed and the crown was sectioned into halves. The convex enamel surfaces were reduced by polishing on silicone paper to prepare a flat surface. The bonding systems were applied on this surface. Prior to adhesive curing, a hollow cylinder (2.0 mm height/0.75 mm internal diameter) was placed on the treated surfaces. A resin composite was then inserted into the tube and cured. After water storage for 24 h, the tube was removed and shear bond strength was determined in a universal testing machine at a crosshead speed of 0.5 mm/min. The results were analyzed with ANOVA and the Tukey.-Kramer test at a 59 degrees confidence level. The enamel of five additional teeth was ground, and the etching component of each adhesive was applied and removed with absolute ethanol instead of being light cured. These teeth and selected fractured surfaces were examined by SEM. Adhesion to ground enamel of the Futurabond DC (25 +/- 3.5 MPa) and Clearfil SE Bond (23 +/- 2.9 MPa) self-etching systems was not significantly different from the etch-and-rinse system Admira Bond (27 +/- 2.3 MPa). The two self-etching adhesives Clearfil S Tri bond and Hybrid Bond demonstrated significantly lower bond strengths (14 +/- 1.4 MPa; 11 +/- 1.9 MPa) with no significant differences between them (p adhesive systems are dependent on the type of adhesive system. Some of the new adhesive systems showed bond strength values comparable to that of etch-and-rinse systems. There was no correlation between bond strength and morphological changes in

Measurement of Ca, Zn and Sr in enamel of human teeth by XRF

Energy Technology Data Exchange (ETDEWEB)

Wielopolski, L.; Featherstone, J.D.B.; Cohn, S.H.

1984-01-01

Energy dispersive x-ray fluorescence (EDXRF) has been employed to measure Ca, Zn, and Sr in enamel of human teeth. The calibration of the EDXRF system was performed by comparing Sr/Ca ratios with values obtained by atomic absorption analysis of acid etched biopsies of the enamel surface. Two calibration lines were obtained, one line for untreated teeth and the second line for teeth immersed (treated) in solutions containing Sr. A simple analytical model demonstrated that the two calibration lines were the result of the difference in the depth of the enamel sampled by EDXRF and by the acid-etched biopsy. The multi-elemental, non-destructive and quantitative aspects of EDXRF permit the sequential monitoring of the effects of Sr and Zn ions on the mineralization and demineralization processes in human enamel. The portability of the system and adaptability to non-invasive measurements makes it suitable for field studies. 26 references, 4 figures.

Measurement of Ca, Zn and Sr in enamel of human teeth by XRF

International Nuclear Information System (INIS)

Wielopolski, L.; Featherstone, J.D.B.; Cohn, S.H.

1984-01-01

Energy dispersive x-ray fluorescence (EDXRF) has been employed to measure Ca, Zn, and Sr in enamel of human teeth. The calibration of the EDXRF system was performed by comparing Sr/Ca ratios with values obtained by atomic absorption analysis of acid etched biopsies of the enamel surface. Two calibration lines were obtained, one line for untreated teeth and the second line for teeth immersed (treated) in solutions containing Sr. A simple analytical model demonstrated that the two calibration lines were the result of the difference in the depth of the enamel sampled by EDXRF and by the acid-etched biopsy. The multi-elemental, non-destructive and quantitative aspects of EDXRF permit the sequential monitoring of the effects of Sr and Zn ions on the mineralization and demineralization processes in human enamel. The portability of the system and adaptability to non-invasive measurements makes it suitable for field studies. 26 references, 4 figures

Measurement of Ca, Zn, and Sr in enamel of human teeth by XRF

International Nuclear Information System (INIS)

Wielopolski, L.; Featherstone, J.D.b.; Cohn, S.H.

1984-01-01

Energy dispersive x-ray fluorescence (EDXRF) has been employed to measure Ca, Zn, and Sr in enamel of human teeth. The calibration of the EDXRF system was performed by comparing Sr/Ca ratios with values obtained by atomic absorption analysis of acid etched biopsies of the enamel surface. Two calibration lines were obtained, one line for untreated teeth and the second line for teeth immersed (treated) in solutions containing Sr. A simple analytical model demonstrated that the two calibration lines were the result of the difference in the depth of the enamel sampled by EDXRF and by the acid-etched biopsy. The multi-elemental, non-destructive and quantitative aspects of EDXRF permit the sequential monitoring of the effects of Sr and Zn ions on the mineralization and demineralization processes in human enamel. The portability of the system and adaptability to non-invasive measurements makes it suitable for field studies. 26 references, 4 figures

Enamel proteins mitigate mechanical and structural degradations in mature human enamel during acid attack

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Lubarsky, Gennady V.; Lemoine, Patrick; Meenan, Brian J.; Deb, Sanjukta; Mutreja, Isha; Carolan, Patrick; Petkov, Nikolay

2014-04-01

A hydrazine deproteination process was used to investigate the role of enamel proteins in the acid erosion of mature human dental enamel. Bright field high resolution transmission electron micrographs and x-ray diffraction analysis show no crystallographic changes after the hydrazine treatment with similar nanoscale hydroxyapatite crystallite size and orientation for sound and de-proteinated enamel. However, the presence of enamel proteins reduces the erosion depth, the loss of hardness and the loss of structural order in enamel, following exposure to citric acid. Nanoindentation creep is larger for sound enamel than for deproteinated enamel but it reduces in sound enamel after acid attack. These novel results are consistent with calcium ion-mediated visco-elasticty in enamel matrix proteins as described previously for nacre, bone and dental proteins. They are also in good agreement with a previous double layer force spectroscopy study by the authors which found that the proteins electrochemically buffer enamel against acid attack. Finally, this suggests that acid attack, and more specifically dental erosion, is influenced by ionic permeation through the enamel layer and that it is mitigated by the enamel protein matrix.

Enamel proteins mitigate mechanical and structural degradations in mature human enamel during acid attack

International Nuclear Information System (INIS)

Lubarsky, Gennady V; Lemoine, Patrick; Meenan, Brian J; Deb, Sanjukta; Mutreja, Isha; Carolan, Patrick; Petkov, Nikolay

2014-01-01

A hydrazine deproteination process was used to investigate the role of enamel proteins in the acid erosion of mature human dental enamel. Bright field high resolution transmission electron micrographs and x-ray diffraction analysis show no crystallographic changes after the hydrazine treatment with similar nanoscale hydroxyapatite crystallite size and orientation for sound and de-proteinated enamel. However, the presence of enamel proteins reduces the erosion depth, the loss of hardness and the loss of structural order in enamel, following exposure to citric acid. Nanoindentation creep is larger for sound enamel than for deproteinated enamel but it reduces in sound enamel after acid attack. These novel results are consistent with calcium ion-mediated visco-elasticty in enamel matrix proteins as described previously for nacre, bone and dental proteins. They are also in good agreement with a previous double layer force spectroscopy study by the authors which found that the proteins electrochemically buffer enamel against acid attack. Finally, this suggests that acid attack, and more specifically dental erosion, is influenced by ionic permeation through the enamel layer and that it is mitigated by the enamel protein matrix. (papers)

Influence of pH, bleaching agents, and acid etching on surface wear of bovine enamel

Science.gov (United States)

Soares, Ana Flávia; Bombonatti, Juliana Fraga Soares; Alencar, Marina Studart; Consolmagno, Elaine Cristina; Honório, Heitor Marques; Mondelli, Rafael Francisco Lia

2016-01-01

ABSTRACT Development of new materials for tooth bleaching justifies the need for studies to evaluate the changes in the enamel surface caused by different bleaching protocols. Objective The aim of this study was to evaluate the bovine dental enamel wear in function of different bleaching gel protocols, acid etching and pH variation. Material and Methods Sixty fragments of bovine teeth were cut, obtaining a control and test areas. In the test area, one half received etching followed by a bleaching gel application, and the other half, only the bleaching gel. The fragments were randomly divided into six groups (n=10), each one received one bleaching session with five hydrogen peroxide gel applications of 8 min, activated with hybrid light, diode laser/blue LED (HL) or diode laser/violet LED (VHL) (experimental): Control (C); 35% Total Blanc Office (TBO35HL); 35% Lase Peroxide Sensy (LPS35HL); 25% Lase Peroxide Sensy II (LPS25HL); 15% Lase Peroxide Lite (LPL15HL); and 10% hydrogen peroxide (experimental) (EXP10VHL). pH values were determined by a pHmeter at the initial and final time periods. Specimens were stored, subjected to simulated brushing cycles, and the superficial wear was determined (μm). ANOVA and Tukey´s tests were applied (α=0.05). Results The pH showed a slight decrease, except for Group LPL15HL. Group LPS25HL showed the highest degree of wear, with and without etching. Conclusion There was a decrease from the initial to the final pH. Different bleaching gels were able to increase the surface wear values after simulated brushing. Acid etching before bleaching increased surface wear values in all groups. PMID:27008254

The effect of additional enamel etching and a flowable composite to the interfacial integrity of Class II adhesive composite restorations.

Science.gov (United States)

Belli, S; Inokoshi, S; Ozer, F; Pereira, P N; Ogata, M; Tagami, J

2001-01-01

This in vitro study evaluated the interfacial integrity of Class II resin composite restorations. The influence of a flowable composite and additional enamel etching was also evaluated. Deep, saucer-shaped Class II cavities were prepared in the mesial and distal proximal surfaces of 25 extracted human molars and assigned to five treatment groups. The gingival margins were extended to approximately 1 mm above the CEJ in 40 cavities and below the CEJ in 10 cavities. The prepared cavities were then restored with a self-etching primer system (Clearfil Liner Bond II) and a hybrid resin composite (Clearfil AP-X), with and without a flowable composite (Protect Liner F) and additional enamel etching with 37% phosphoric acid gel (K-etchant). After finishing, polishing and thermocycling (4 and 60 degrees C, x300), the samples were longitudinally sectioned through the restorations and resin-tooth interfaces were observed directly under a laser scanning microscope. Statistical analysis indicated that the use of a flowable composite produced significantly more (p = 0.04) gap-free resin-dentin interfaces than teeth restored without the flowable composite. However, both flowable composite and enamel etching could not prevent gap formation at enamel-resin interfaces and crack formation on enamel walls.

Two-year water degradation of self-etching adhesives bonded to bur ground enamel

NARCIS (Netherlands)

Abdalla, A.I.; Feilzer, A.J.

2009-01-01

To evaluate the effect of water storage on the microshear bond strength to ground enamel of three "all-in-one" self-etch adhesives: Futurabond DC, Clearfil S Tri Bond and Hybrid bond; a self-etching primer; Clearfil SE Bond and an etch-and-rinse adhesive system, Admira Bond. Sixty human molars were

Tensile bond strength and SEM analysis of enamel etched with Er:YAG laser and phosphoric acid: a comparative study in vitro

International Nuclear Information System (INIS)

Sasaki, Luis H.; Tanaka, Celso Shin-Ite; Lobo, Paulo D.C.; Villaverde, Antonio B.; Moriyama, Eduardo H.; Brugnera Junior, Aldo; Moriyama, Yumi; Watanabe, Ii-Sei

2008-01-01

Er:YAG laser has been studied as a potential tool for restorative dentistry due to its ability to selectively remove oral hard tissue with minimal or no thermal damage to the surrounding tissues. The purpose of this study was to evaluate in vitro the tensile bond strength (TBS) of an adhesive/composite resin system to human enamel surfaces treated with 37% phosphoric acid, Er:YAG laser (λ=2.94 μm) with a total energy of 16 J (80 mJ/pulse, 2Hz, 200 pulses, 250 ms pulse width), and Er:YAG laser followed by phosphoric acid etching. Analysis of the treated surfaces was performed by scanning electron microscopy (SEM) to assess morphological differences among the groups. TBS means (in MPa) were as follows: Er:YAG laser + acid (11.7 MPa) > acid (8.2 MPa) > Er:YAG laser (6.1 MPa), with the group treated with laser+acid being significantly from the other groups (p=0.0006 and p= 0.00019, respectively). The groups treated with acid alone and laser alone were significantly different from each other (p=0.0003). The SEM analysis revealed morphological changes that corroborate the TBS results, suggesting that the differences in TBS means among the groups are related to the different etching patterns produced by each type of surface treatment. The findings of this study indicate that the association between Er:YAG laser and phosphoric acid can be used as a valuable resource to increase bond strength to laser-prepared enamel. (author)

Comparison of enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives in self-etch mode.

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Tsujimoto, Akimasa; Barkmeier, Wayne W; Hosoya, Yumiko; Nojiri, Kie; Nagura, Yuko; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2017-10-01

To comparatively evaluate universal adhesives and two-step self-etch adhesives for enamel bond fatigue durability in self-etch mode. Three universal adhesives (Clearfil Universal Bond; G-Premio Bond; Scotchbond Universal Adhesive) and three two-step self-etch adhesives (Clearfil SE Bond; Clearfil SE Bond 2; OptiBond XTR) were used. The initial shear bond strength and shear fatigue strength of the adhesive to enamel in self-etch mode were determined. The initial shear bond strengths of the universal adhesives to enamel in self-etch mode was significantly lower than those of two-step self-etch adhesives and initial shear bond strengths were not influenced by type of adhesive in each adhesive category. The shear fatigue strengths of universal adhesives to enamel in self-etch mode were significantly lower than that of Clearfil SE Bond and Clearfil SE Bond 2, but similar to that OptiBond XTR. Unlike two-step self-etch adhesives, the initial shear bond strength and shear fatigue strength of universal adhesives to enamel in self-etch mode was not influenced by the type of adhesive. This laboratory study showed that the enamel bond fatigue durability of universal adhesives was lower than Clearfil SE Bond and Clearfil SE Bond 2, similar to Optibond XTR, and was not influenced by type of adhesive, unlike two-step self-etch adhesives.

In vitro evaluation of microleakage around orthodontic brackets using laser etching and Acid etching methods.

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Mohammad Hossein Toodehzaeim

2014-06-01

Full Text Available path of microleakage between the enamel and adhesive potentially allows microbial ingress that may consequently cause enamel decalcification. The aim of this study was to compare microleakage of brackets bonded either by laser or acid etching techniques.The specimens were 33 extracted premolars that were divided into three groups as the acid etching group (group 1, laser etching with Er:YAG at 100 mJ and 15 Hz for 15s (group 2, and laser etching with Er:YAG at 140 mJ and 15 Hz for 15s (group 3. After photo polymerization, the teeth were subjected to 500 thermal cycles. Then the specimens were sealed with nail varnish, stained with 2% methylen blue for 24hs, sectioned, and examined under a stereomicroscope. They were scored for marginal microleakage that occurred between the adhesive-enamel and bracket-adhesive interfaces from the occlusal and gingival margins. Data were analyzed with the Kruskal- Wallis test.For the adhesive-enamel and bracket-adhesive surfaces, significant differences were not observed between the three groups.According to this study, the Er:YAG laser with 1.5 and 2.1 watt settings may be used as an adjunctive for preparing the surface for orthodontic bracket bonding.

Bonding characteristics of self-etching adhesives to intact versus prepared enamel.

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Perdigão, Jorge; Geraldeli, Saulo

2003-01-01

This study tested the null hypothesis that the preparation of the enamel surface would not affect the enamel microtensile bond strengths of self-etching adhesive materials. Ten bovine incisors were trimmed with a diamond saw to obtain a squared enamel surface with an area of 8 x 8 mm. The specimens were randomly assigned to five adhesives: (1) ABF (Kuraray), an experimental two-bottle self-etching adhesive; (2) Clearfil SE Bond (Kuraray), a two-bottle self-etching adhesive; (3) One-Up Bond F (Tokuyama), an all-in-one adhesive; (4) Prompt L-Pop (3M ESPE), an all-in-one adhesive; and (5) Single Bond (3M ESPE), a two-bottle total-etch adhesive used as positive control. For each specimen, one half was roughened with a diamond bur for 5 seconds under water spray, whereas the other half was left unprepared. The adhesives were applied as per manufacturers' directions. A universal hybrid composite resin (Filtek Z250, 3M ESPE) was inserted in three layers of 1.5 mm each and light-cured. Specimens were sectioned in X and Y directions to obtain bonded sticks with a cross-sectional area of 0.8 +/- 0.2 mm2. Sticks were tested in tension in an Instron at a cross-speed of 1 mm per minute. Statistical analysis was carried out with two-way analysis of variance and Duncan's test at p adhesive, resulted in statistically higher microtensile bond strength than any of the other adhesives regardless of the enamel preparation (unprepared = 31.5 MPa; prepared = 34.9 MPa, not statistically different at p adhesives resulted in higher microtensile bond strength when enamel was roughened than when enamel was left unprepared. However, for ABF and for Clearfil SE Bond this difference was not statistically significant at p > .05. When applied to ground enamel, mean bond strengths of Prompt L-Pop were not statistically different from those of Clearfil SE Bond and ABF. One-Up Bond F did not bond to unprepared enamel. Commercial self-etching adhesives performed better on prepared enamel than on

Enamel microhardness and bond strengths of self-etching primer adhesives.

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Adebayo, Olabisi A; Burrow, Michael F; Tyas, Martin J; Adams, Geoffrey G; Collins, Marnie L

2010-04-01

The aim of this study was to determine the relationship between enamel surface microhardness and microshear bond strength (microSBS). Buccal and lingual mid-coronal enamel sections were prepared from 22 permanent human molars and divided into two groups, each comprising the buccal and lingual enamel from 11 teeth, to analyze two self-etching primer adhesives (Clearfil SE Bond and Tokuyama Bond Force). One-half of each enamel surface was tested using the Vickers hardness test with 10 indentations at 1 N and a 15-s dwell time. A hybrid resin composite was bonded to the other half of the enamel surface with the adhesive system assigned to the group. After 24 h of water storage of specimens at 37 degrees C, the microSBS test was carried out on a universal testing machine at a crosshead speed of 1 mm min(-1) until bond failure occurred. The mean microSBS was regressed on the mean Vickers hardness number (VHN) using a weighted regression analysis in order to explore the relationship between enamel hardness and microSBS. The weights used were the inverse of the variance of the microSBS means. Neither separate correlation analyses for each adhesive nor combined regression analyses showed a significant correlation between the VHN and the microSBS. These results suggest that the microSBS of the self-etch adhesive systems are not influenced by enamel surface microhardness.

Bond strength of one-step self-etch adhesives and their predecessors to ground versus unground enamel.

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Yazici, A Ruya; Yildirim, Zeren; Ertan, Atila; Ozgunaltay, Gül; Dayangac, Berrin; Antonson, Sibel A; Antonson, Donald E

2012-07-01

The aim of this study was to compare the shear bond strength of several self-etch adhesives to their two-step predecessors to ground and unground enamel. Seventy-five extracted, non-carious human third molar teeth were selected for this study. The buccal surfaces of each tooth were mechanically ground to obtain flat enamel surfaces (ground enamel), while the lingual surfaces were left intact (unground enamel). The teeth were randomly divided into five groups according to the adhesive systems (n=15): one-step self-etch adhesive - Clearfil S3 Bond, its two-step predecessor - Clearfil SE Bond, one-step self-etch adhesive - AdheSE One, and its two-step predecessor - AdheSE, and a two-step etch-and-rinse adhesive - Adper Single Bond 2(control). After application of the adhesives to the buccal and lingual enamel surfaces of each tooth, a cylindrical capsule filled with a hybrid composite resin (TPH) was seated against the surfaces. The specimens were stored in distilled water at 37°C for 24 hours, followed by thermocy-cling (5°C-55°C/500 cycles). They were subjected to shear bond strength test in a universal testing machine at a crosshead speed of 1.0 mm/minute. The data were compared using a two-way ANOVA, followed by Bonferroni test at Padhesives exhibited statistically similar bond strengths to ground and unground enamel except for the etch-and-rinse adhesive that showed significantly higher bond strengths than the self-etch adhesives (Padhesives tested (P=.17). Similar bond strengths to ground and unground enamel were achieved with one-step self-etch adhesives and their predecessors. Enamel preparation did not influence the bonding performance of the adhesives tested.

Bond strength of one-step self-etch adhesives and their predecessors to ground versus unground enamel

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Yazici, A. Ruya; Yildirim, Zeren; Ertan, Atila; Ozgunaltay, Gül; Dayangac, Berrin; Antonson, Sibel A; Antonson, Donald E

2012-01-01

Objective The aim of this study was to compare the shear bond strength of several self-etch adhesives to their two-step predecessors to ground and unground enamel. Methods: Seventy-five extracted, non-carious human third molar teeth were selected for this study. The buccal surfaces of each tooth were mechanically ground to obtain flat enamel surfaces (ground enamel), while the lingual surfaces were left intact (unground enamel). The teeth were randomly divided into five groups according to the adhesive systems (n=15): one-step self-etch adhesive - Clearfil S3 Bond, its two-step predecessor - Clearfil SE Bond, one-step self-etch adhesive - AdheSE One, and its two-step predecessor - AdheSE, and a two-step etch-and-rinse adhesive - Adper Single Bond 2(control). After application of the adhesives to the buccal and lingual enamel surfaces of each tooth, a cylindrical capsule filled with a hybrid composite resin (TPH) was seated against the surfaces. The specimens were stored in distilled water at 37°C for 24 hours, followed by thermocy-cling (5°C–55°C/500 cycles). They were subjected to shear bond strength test in a universal testing machine at a crosshead speed of 1.0 mm/minute. The data were compared using a two-way ANOVA, followed by Bonferroni test at Padhesives exhibited statistically similar bond strengths to ground and unground enamel except for the etch-and-rinse adhesive that showed significantly higher bond strengths than the self-etch adhesives (Penamel for any of the adhesives tested (P=.17). Conclusion: Similar bond strengths to ground and unground enamel were achieved with one-step self-etch adhesives and their predecessors. Enamel preparation did not influence the bonding performance of the adhesives tested. PMID:22904656

A comparison of orthodontic bracket shear bond strength on enamel deproteinized by 5.25% sodium hypochlorite using total etch and self-etch primer

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Ongkowidjaja, F.; Soegiharto, B. M.; Purbiati, M.

2017-08-01

The shear bond strength (SBS) can be increased by removing protein pellicles from the enamel surface by deproteinization using 5.25% sodium hypochlorite (NaOCl). The SBS of a self-etch primer is lower than that of a total etch primer; nonetheless, it prevents white spot lesions. This study aimed to assess the SBS of the Anyetch (AE) total etch primer and FL-Bond II Shofu (FL) self-etch primer after enamel deproteinization using 5.25% NaOCl. Forty eight human maxillary first premolars were extracted, cleaned, and divided into four groups. In group A, brackets were bonded to the enamel without deproteinization before etching (A1: 10 teeth using total etch primer (AE); A2: 10 teeth using self-etch primer (FL)). In group B, brackets were bonded to the enamel after deproteinization with 5.25% NaOCl before etching (B1: 10 teeth using total etch primer (AE); B2: 10 teeth using self-etch primer (FL)). Brackets were bonded using Transbond XT, stored in artificial saliva for 24 h at 37°C, mounted on acrylic cylinders, and debonded using a Shimadzu AG-5000 universal testing machine. There were no significant differences in SBS between the total etch (AE) groups (p > 0.05) and between the self-etch (FL) groups (p > 0.05). There were significant differences in SBS between groups A and B. The mean SBS for groups A1, A2, B1, and B2 was 12.91±3.99, 4.46±2.47, 13.06±3.66, and 3.62±2.36 MPa, respectively. Deproteinization using NaOCl did not affect the SBS of the total etch primer (AE) group; it reduced the SBS of the self-etch primer (FL) group, but not with a statistically significant difference.

In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method

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Wu, Xiaoguang; Zhao, Xu; Li, Yi; Yang, Tao; Yan, Xiujuan; Wang, Ke

2015-01-01

In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO 3 layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO 3 layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO 3 coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). - Graphical abstract: FESEM images of enamel slices etched for 60 s and repaired by the two-step method with Glu concentration of 20.00 mmol/L. (A) The boundary (dotted line) of the repaired areas (b) and unrepaired areas (a). (Some selected areas of etched enamel slices were coated with a nail polish before the reaction, which was removed by acetone after the reaction); (B) high magnification image of Ga, (C) high magnification image of Gb. In situ fabrication of carbonated

In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method

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Wu, Xiaoguang [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China); Zhao, Xu [College of Chemistry, Jilin University, Changchun 130021 (China); Li, Yi, E-mail: lyi99@jlu.edu.cn [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China); Yang, Tao [Department of Stomatology, Children' s Hospital of Changchun, 130051 (China); Yan, Xiujuan; Wang, Ke [Department of Pediatric Dentistry, The Hospital of Stomatology, Jilin University, Changchun 130021 (China)

2015-09-01

In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO{sub 3} layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO{sub 3} layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO{sub 3} coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). - Graphical abstract: FESEM images of enamel slices etched for 60 s and repaired by the two-step method with Glu concentration of 20.00 mmol/L. (A) The boundary (dotted line) of the repaired areas (b) and unrepaired areas (a). (Some selected areas of etched enamel slices were coated with a nail polish before the reaction, which was removed by acetone after the reaction); (B) high magnification image of Ga, (C) high magnification image of Gb. In situ fabrication of

Influence of de/remineralization of enamel on the tensile bond strength of etch-and-rinse and self-etching adhesives.

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Farias de Lacerda, Ana Julia; Ferreira Zanatta, Rayssa; Crispim, Bruna; Borges, Alessandra Bühler; Gomes Torres, Carlos Rocha; Tay, Franklin R; Pucci, Cesar Rogério

2016-10-01

To evaluate the bonding behavior of resin composite and different adhesives applied to demineralized or remineralized enamel. Bovine tooth crowns were polished to prepare a 5 mm2 enamel bonding area, and divided into five groups (n= 48) according to the surface treatment: CONT (sound enamel control), DEM (demineralized with acid to create white spot lesions), REMS (DEM remineralized with artificial saliva), REMF (DEM remineralized with sodium fluoride) and INF (DEM infiltrated with Icon resin infiltrant). The surface-treated teeth were divided into two subgroups (n= 24) according to adhesive type: ER (etch-and-rinse; Single Bond Universal) and SE (self-etching; Clearfill S3 Bond), and further subdivided into two categories (n= 12) according to aging process: Thermo (thermocycling) and NA (no aging). Composite blocks were made over bonded enamel and sectioned for microtensile bond strength (MTBS) testing. Data were analyzed with three-way ANOVA and post-hoc Tukey's test (α= 0.05). Significant differences were observed for enamel surface treatment (Padhesive type (PUniversal had higher MTBS than Clearfil S3 Bond; thermo-aging resulted in lower MTBS irrespective of adhesive type and surface treatment condition. The predominant failure mode was mixed for all groups. Enamel surface infiltrated with Icon does not interfere with adhesive resin bonding procedures. Treatment of enamel surface containing white spot lesions or cavities with cavosurface margins in partially-demineralized enamel can benefit from infiltration with a low viscosity resin infiltrant prior to adhesive bonding of resin composites.

Effect of acidity upon attrition-corrosion of human dental enamel.

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Wu, Yun-Qi; Arsecularatne, Joseph A; Hoffman, Mark

2015-04-01

Attrition-corrosion is a synthesized human enamel wear process combined mechanical effects (attrition) with corrosion. With the rising consumption of acidic food and beverages, attrition-corrosion is becoming increasingly common. Yet, research is limited and the underlying mechanism remains unclear. In this study, in vitro wear loss of human enamel was investigated and the attrition-corrosion process and wear mechanism were elucidated by the analysis of the wear scar and its subsurface using focused ion beam (FIB) sectioning and scanning electron microscopy (SEM). Human enamel flat-surface samples were prepared with enamel cusps as the wear antagonists. Reciprocating wear testing was undertaken under load of 5N at the speed of 66 cycle/min for 2250 cycles with lubricants including citric acid (at pH 3.2 and 5.5), acetic acid (at pH 3.2 and 5.5) and distilled water. All lubricants were used at 37°C. Similar human enamel flat-surface samples were also exposed to the same solutions as a control group. The substance loss of enamel during wear can be linked to the corrosion potential of a lubricant used. Using a lubricant with very low corrosion potential (such as distilled water), the wear mechanism was dominated by delamination with high wear loss. Conversely, the wear mechanism changed to shaving of the softened layer with less material loss in an environment with medium corrosion potential such as citric acid at pH 3.2 and 5.5 and acetic acid at pH 5.5. However, a highly corrosive environment (e.g., acetic acid at pH 3.2) caused the greatest loss of substance during wear. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluating the shear bond strength of enamel and dentin with or without etching: A comparative study between dimethacrylate-based and silorane-based adhesives

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Hajizadeh, Hila; Nasseh, Atefeh; Rahmanpour, Naim

2015-01-01

Background Silorane-based composites and their specific self-etch adhesive were introduced to conquest the polymerization shrinkage of methacrylate-based composites. It has been shown that additional etching of enamel and dentin can improve the bond strength of self-etch methacrylate-based adhesives but this claim is not apparent about silorane-based adhesives. Our objective was to compare the shear bond strength (SBS) of enamel and dentin between silorane-based adhesive resin and a methacrylate-based resin with or without additional etching. Material and Methods 40 sound human premolars were prepared and divided into two groups: 1- Filtek P60 composite and Clearfil SE Bond adhesive; 2- Filtek P90 composite and Silorane adhesive. Each group divided into two subgroups: with or without additional etching. For additional etching, 37% acid phosphoric was applied before bonding procedure. A cylinder of the composite was bonded to the surface. After 24 hours storage and 500 thermo cycling between 5-55°C, shear bond strength was assessed with the cross head speed of 0.5 mm/min. Then, bonded surfaces were observed under stereomicroscope to determine the failure mode. Data were analyzed with two-way ANOVA and Fischer exact test. Results Shear bond strength of Filtek P60 composite was significantly higher than Filtek P90 composite both in enamel and dentin surfaces (Penamel or dentin for each of the composites (P>0.05). There was no interaction between composite type and additional etching (P>0.05). Failure pattern was mainly adhesive and no significant correlation was found between failure and composite type or additional etching (P>0.05). Conclusions Shear bond strength of methacrylate-based composite was significantly higher than silorane-based composite both in enamel and dentin surfaces and additional etching had no significant effect on shear bond strength in enamel or dentin for each of the composites. The mode of failure had no meaningful relation to the type of

Effect of a whitening agent application on enamel bond strength of self-etching primer systems.

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Miyazaki, Masashi; Sato, Hikaru; Sato, Tomomi; Moore, B Keith; Platt, Jeffrey A

2004-06-01

Though reduction in bond strength after tooth whitening has been reported, little is known about it's effect on enamel bond strength of two-step bonding systems that exclude phosphoric acid etching prior to bonding agent application. The purpose of this study was to determine the effect of whitening procedure using an in-office whitening agent on enamel bond strength of self-etching primer systems. Three self-etching primer systems, Imperva Fluoro Bond, Mac Bond II, Clearfil SE Bond, and a one-bottle adhesive system Single Bond as a control material, were used. Bovine mandibular incisors were mounted in self-curing resin and the facial enamel or dentin surfaces were ground wet on 600-grit SiC paper. An in-office whitening agent, Hi-Lite was applied on the tooth surface according to the manufacturer's instruction. Bonding procedures were done soon after rinsing off the whitening agent or after 24 hours storage in distilled water. Specimens without whitening procedure were prepared as controls. Fifteen specimens per test group were stored in 37 degrees C distilled water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA followed by Duncan multiple range test were used for statistical analysis of the results. For the specimens made soon after rinsing off the whitening agent, a significant decrease in enamel bond strength was observed for all the bonding systems used. For the specimens made after 24 hours storage in water, a small decrease in enamel bond strength was observed and no significant differences were found compared to those of controls (without whitening). From the results of this study, enamel bond strengths of the self-etching primer systems might be affected to a lesser degree after rinsing with water followed by 24 hours storage in water.

Influence of Different Etching Modes on Bond Strength to Enamel using Universal Adhesive Systems.

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Diniz, Ana Cs; Bandeca, Matheus C; Pinheiro, Larissa M; Dos Santosh Almeida, Lauber J; Torres, Carlos Rg; Borges, Alvaro H; Pinto, Shelon Cs; Tonetto, Mateus R; De Jesus Tavarez, Rudys R; Firoozmand, Leily M

2016-10-01

The adhesive systems and the techniques currently used are designed to provide a more effective adhesion with reduction of the protocol application. The objective of this study was to evaluate the bond strength of universal adhesive systems on enamel in different etching modes (self-etch and total etch). The mesial and distal halves of 52 bovine incisors, healthy, freshly extracted, were used and divided into seven experimental groups (n = 13). The enamel was treated in accordance with the following experimental conditions: FUE-Universal System - Futurabond U (VOCO) with etching; FUWE - Futurabond U (VOCO) without etching; SB-Total Etch System - Single Bond 2 (3M); SBUE-Universal System - Single Bond Universal (3M ESPE) with etching; SBUWE - Single Bond Universal (3M ESPE) without etching; CLE-Self-etch System - Clearfil SE Bond (Kuraray) was applied with etching; CLWE - Clearfil SE Bond (Kuraray) without etching. The specimens were made using the composite spectrum TPH (Dentsply) and stored in distilled water (37 ± 1°C) for 1 month. The microshear test was performed using the universal testing machine EMIC DL 2000 with the crosshead speed of 0.5 mm/minute. The bond strength values were analyzed using statistical tests (Kruskal-Wallis test and Mann-Whitney test) with Bonferroni correction. There was no statistically significant difference between groups (p adhesive interface revealed that most failures occurred between the interface composite resin and adhesive. The universal adhesive system used in dental enamel varies according to the trademark, and the previous enamel etching for universal systems and the self-etch both induced greater bond strength values. Selective enamel etching prior to the application of a universal adhesive system is a relevant strategy for better performance bonding.

Shear Bond Strength of Saliva Contaminated and Re-etched All-in-One Adhesive to Enamel

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M. Khoroushi

2008-12-01

Full Text Available Objective: The aim of this study was to investigate the effect of phosphoric acid re-etching of an enamel surface treated via a one-bottle adhesive system on shear bond strength between resin composite and the enamelsurface in different stages of adhesive application.Materials and Methods: Extracted intact premolars (n=84 were divided into sevengroups (n=12. In the control group 1, the adhesive i-Bond was used according to the manufacturer's instructions, with nocontamination. In groups 2 to 4, the conditioned and saliva, contaminated enamel was blot dried only, rinsed,and blot dried, rinsed blot dried and re-etched, respectively. In groups 5, 6and 7 cured adhesive was contaminated with saliva and then rinsed and blot-dried, blot dried only and rinsed, blot-dried and re-etched respectively. In groups 3, 4, 6 and 7 the adhesive was reapplied. Afterward, Z100 compos-ite cylinders were bonded to the enamel surfaces. The samples were thermocycled (5°C and 55°C, 30 s, dwelling time: 10 s, 500 cycles. Finally, the samples were sheared using Dartec testing machine and shear bond strength data were subjected to one-way ANOVA analysis and Tukey's HSD test.Results: There were statistically significant differences among groups 1 and 5-7. The samples in groups 1 and 4 demonstrated higher bond strengths than those in the other groups.Conclusion: Using phosphoric acid etching may be effective, only where contamination occurs prior to curing of the adhesive. After curing of the adhesive, none of the methods in this study would be preferred.

Comparative study of the shear bond strength of composite resin bonded to enamel treated with acid etchant and erbium, chromium: Yttrium, scandium, gallium, garnet laser

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Adel Sulaiman Alagl

2016-01-01

Full Text Available Aim: The purpose of this investigation is in vitro comparison of the shear bond strength (SBS of composite resin bonded to enamel pretreated with an acid etchant against enamel etched with erbium, chromium: yttrium, scandium, gallium, garnet (Er, Cr:YSGG laser. Materials and Methods: Sixty premolars were sectioned mesiodistally and these 120 specimens were separated into two groups of 60 each (Groups A and B. In Group A (buccal surfaces, enamel surface was etched using 37% phosphoric acid for 15 s. In Group B (lingual surfaces, enamel was laser-etched at 2W for 10 s by Er, Cr:YSGG laser operational at 2780 nm with pulse duration of 140 μs and a frequency of 20 Hz. After application of bonding agent on all test samples, a transparent plastic cylinder of 1.5 mm × 3 mm was loaded with composite and bonded by light curing for 20 s. All the samples were subjected to SBS analysis using Instron Universal testing machine. Failure modes were observed under light microscope and grouped as adhesive, cohesive, and mixed. Failure mode distributions were compared using the Chi-square test. Results: SBS values obtained for acid-etched enamel were in the range of 7.12–28.36 megapascals (MPa and for laser-etched enamel were in the range of 6.23–23.35 MPa. Mean SBS for acid-etched enamel was 15.77 ± 4.38 MPa, which was considerably greater (P < 0.01 than laser-etched enamel 11.24 ± 3.76 MPa. The Chi-square test revealed that the groups showed no statistically significant differences in bond failure modes. Conclusions: We concluded that the mean SBS of composite with acid etching is significantly higher as compared to Er, Cr: YSGG (operated at 2W for 10 s laser-etched enamel.

Influence of microhybrid resin and etching times on bleached enamel for the bonding of ceramic brackets

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Leily Macedo Firoozmand

2013-04-01

Full Text Available The aim of this study was to evaluate the shear bond strength (SBS of polycrystalline ceramic brackets (PCB bonded after bleaching treatment using different composite resins and enamel etching times. A total of 144 bovine incisors were randomly divided into two study groups (n = 72, each as follows: G1, enamel bleached with 35% hydrogen peroxide, and G2 (control group, enamel unbleached. After the bleaching treatment, the samples were stored in artificial saliva for 14 days. These groups were further divided into two subgroups (n = 36, each as follows: GA, brackets bonded with Transbond XT (3M and GB, brackets bonded with Filtek Z250 (3M. For each resin used, three different etching times with 37% phosphoric acid (15, 30 and 60 seconds were tested. SBS tests were performed using a universal testing machine (EMIC, and the adhesive remnant index (ARI score was verified. Significant differences among the three experimental conditions and interactions between the groups were observed. The type of composite resin accounted for 24% of the influence on the bond strength, whereas the etching time and bleaching treatment accounted for 14.5% and 10% of the influence on bond strength, respectively. The ARI revealed that the most common area of adhesion failure was at the composite resin-bracket interface. The type of composite resin, etching time and external bleaching significantly influenced the SBS of PCB on enamel, even after 14 days of saliva storage.

Self-etch and etch-and-rinse adhesive systems in clinical dentistry.

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Ozer, Fusun; Blatz, Markus B

2013-01-01

Current adhesive systems follow either an "etch-and-rinse" or "self-etch" approach, which differ in how they interact with natural tooth structures. Etch-and-rinse systems comprise phosphoric acid to pretreat the dental hard tissues before rinsing and subsequent application of an adhesive. Self-etch adhesives contain acidic monomers, which etch and prime the tooth simultaneously. Etch-and-rinse adhesives are offered as two- or three-step systems, depending on whether primer and bonding are separate or combined in a single bottle. Similarly, self-etch adhesives are available as one- or two-step systems. Both etch-and-rinse and self-etch systems form a hybrid layer as a result of resins impregnating the porous enamel or dentin. Despite current trends toward fewer and simpler clinical application steps, one-step dentin bonding systems exhibit bonding agent lower bond strengths and seem less predictable than multi-step etch-and-rinse and self-etch systems. The varying evidence available today suggests that the choice between etch-and-rinse and self-etch systems is often a matter of personal preference. In general, however, phosphoric acid creates a more pronounced and retentive etching pattern in enamel. Therefore, etch-and-rinse bonding systems are often preferred for indirect restorations and when large areas of enamel are still present. Conversely, self-etch adhesives provide superior and more predictable bond strength to dentin and are, consequently, recommended for direct composite resin restorations, especially when predominantly supported by dentin.

Bond efficacy and interface morphology of self-etching adhesives to ground enamel

NARCIS (Netherlands)

Abdalla, A.I.; El Zohairy, A.A.; Mohsen, M.M.A.; Feilzer, A.J.

2010-01-01

Purpose: This study compared the microshear bond strengths to ground enamel of three one-step self-etching adhesive systems, a self-etching primer system and an etch-and-rinse adhesive system. Materials and Methods: Three self-etching adhesives, Futurabond DC (Voco), Clearfil S Tri Bond (Kuraray)

Comparison of Enamel Morphologic Characteristics after Conditioning with Various Combinations of Acid Etchant and Er:YAG Laser in Bonding and Rebonding Procedures: A SEM Analysis

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Mohammad Sadegh Ahmad Akhoundi

2017-10-01

Full Text Available Objectives: Many studies have evaluated re-etched enamel by using scanning electron microscopy (SEM; however, there is no evidence regarding the use of Erbium-doped yttrium aluminium garnet (Er:YAG laser at primary and secondary bonding instead of acid etching with regards to enamel surface changes. The purpose of the present study was to determine that whether or not the methods of primary and secondary enamel preparation affect enamel characteristics after rebonding, by using SEM analysis.Materials and Methods: Twelve freshly extracted premolars were divided into 4 groups. The samples in each group were conditioned by acid etchant or Er:YAG laser at primary conditioning, according to the instructions. Afterwards, they were bonded with orthodontic brackets. After debonding, the samples were prepared for second conditioning. Also, two samples were conditioned only once with acid etchant or laser, to compare enamel morphology changes with those after re-etching. Finally, buccal enamel surfaces were evaluated using SEM.Results: Enamel etching patterns were observed in the samples which had been acid-conditioned at first or at both conditionings. The samples irradiated by Er:YAG laser showed amorphous and irregular surfaces, with no signs of typical etching patterns. A large deep gap was seen in one of the samples irradiated with laser at primary and secondary conditionings, which might have penetrated the underling layers of enamel and dentin.Conclusions: Enamel surface preparation with Er:YAG laser produces irregular and indistinct morphologic changes, completely different from those produced after acid etching at both conditioning and reconditioning. Therefore, it is recommended to use this laser with caution to avoid permanent enamel damage.

Impact of pH and application time of meta-phosphoric acid on resin-enamel and resin-dentin bonding.

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Cardenas, A F M; Siqueira, F S F; Bandeca, M C; Costa, S O; Lemos, M V S; Feitora, V P; Reis, A; Loguercio, A D; Gomes, J C

2018-02-01

To evaluate the immediate microshear resin-enamel bond strength (μSBS) and the immediate and 6-month microtensile bond strength (μTBS) and nanoleakage (NL) of the adhesive interface performed by different pHs of 40% meta-phosphoric acid (MPA) were compared with conventional 37% ortho-phosphoric acid (OPA) under different application times. Additionally, the enamel etching patterns were evaluated and the chemical/morphological changes induced by these differents groups were evaluated. One hundred and ninety-eight extracted human molars were randomly assigned into experimental groups according to the combination of independent variables: Acid [37% ortho-phosphoric acid (OPA), 40% meta-phosphoric acid (MPA) at pHs of: 0.5, 1 and 2] and Application Time [7, 15 and 30s]. Enamel-bond specimens were prepared and tested under μSBS. Resin-dentin beams were tested under μTBS tested immediately or after 6-months of water storage. Nanoleakage was evaluated using bonded-beams of each tooth/time-period. Enamel etching pattern and chemical and ultra-morphology analyses were also performed. The μSBS (MPa) data were subjected to a two-way repeated measures ANOVA (Acid vs. Application time). For μTBS, Acid vs application time vs storage time data were subjected to three-way ANOVA and Tukey's test (α = 0.05). MPA pH 0.5 showed μTBS similar to OPA, independently of the application time on enamel (p>0.05) or dentin (p>0.05). OPA provided higher nanoleakage values than MPA (p = 0.003). Significant decreases in TBS and increases in NL were only observed for OPA after 6 months (p = 0.001). An increase in the application time resulted in a more pronounced etching pattern for MPA. Chemical analysis showed that dentin demineralized by MPA depicted peaks of brushite and octacalcium phosphate. MPA exposed less collagen than OPA. However, optimal results for MPA were dependent on pH/application time. The use of 40% meta-phosphoric acid with a pH of 0.5 is an alternative acid-etching

Bond durability of universal adhesive to bovine enamel using self-etch mode.

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Suzuki, Soshi; Takamizawa, Toshiki; Imai, Arisa; Tsujimoto, Akimasa; Sai, Keiichi; Takimoto, Masayuki; Barkmeier, Wayne W; Latta, Mark A; Miyazaki, Masashi

2018-04-01

The purpose of this study was to examine the enamel bond durability of universal adhesives in the self-etch mode under 2-year water storage and thermal cycling conditions. Three commercially available universal adhesives and a gold standard two-step self-etch adhesive were used. Ten specimens of bovine enamel were prepared per test group, and shear bond strength (SBS) was measured to determine the bonding durability after thermal cycling (TC) or long-term water storage (WS). The bonded specimens were divided into three groups: (1) specimens subjected to TC, where the bonded specimens were stored in 37 °C distilled water for 24 h before being subjected to 3000, 10,000, 20,000 or 30,000 TC; (2) specimens stored in 37 °C distilled water for 3 months, 6 months, 1 year or 2 year; and (3) specimens stored in 37 °C distilled water for 24 h, serving as a baseline. The two-step self-etch adhesive showed significantly higher SBS than the universal adhesives tested, regardless of the type of degradation method. All universal adhesives showed no significant enamel SBS reductions in TC and WS, when compared to baseline and the other degradation conditions. Compared to the bond strengths obtained with the two-step self-etch adhesive, significantly lower bond strengths were obtained with universal adhesives. However, the enamel bond durability of universal adhesives was relatively stable under both degradation conditions tested. The present data indicate that the enamel bond durability of universal adhesives in the self-etch mode might be sufficient for clinical use.

Shear bond strength of orthodontic brackets after acid-etched and erbium-doped yttrium aluminum garnet laser-etched

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Shiva Alavi

2014-01-01

Full Text Available Background: Laser ablation has been suggested as an alternative method to acid etching; however, previous studies have obtained contrasting results. The purpose of this study was to compare the shear bond strength (SBS and fracture mode of orthodontic brackets that are bonded to enamel etched with acid and erbium-doped yttrium aluminum garnet (Er:YAG laser. Materials and Methods: In this experimental in vitro study, buccal surfaces of 15 non-carious human premolars were divided into mesial and distal regions. Randomly, one of the regions was etched with 37% phosphoric acid for 15 s and another region irradiated with Er:YAG laser at 100 mJ energy and 20 Hz frequency for 20 s. Stainless steel brackets were then bonded using Transbond XT, following which all the samples were stored in distilled water for 24 h and then subjected to 500 thermal cycles. SBS was tested by a chisel edge, mounted on the crosshead of universal testing machine. After debonding, the teeth were examined under Χ10 magnification and adhesive remnant index (ARI score determined. SBS and ARI scores of the two groups were then compared using t-test and Mann-Whitney U test. Significant level was set at P < 0.05. Results: The mean SBS of the laser group (16.61 ± 7.7 MPa was not significantly different from that of the acid-etched group (18.86 ± 6.09 MPa (P = 0.41. There was no significant difference in the ARI scores between two groups (P = 0.08. However, in the laser group, more adhesive remained on the brackets, which is not suitable for orthodontic purposes. Conclusion: Laser etching at 100 mJ energy produced bond strength similar to acid etching. Therefore, Er:YAG laser may be an alternative method for conventional acid-etching.

Effect of Oxygen Inhibition Layer of Universal Adhesives on Enamel Bond Fatigue Durability and Interfacial Characteristics With Different Etching Modes.

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Ouchi, H; Tsujimoto, A; Nojiri, K; Hirai, K; Takamizawa, T; Barkmeier, W W; Latta, M A; Miyazaki, M

The purpose of this study was to evaluate the effect of the oxygen inhibition layer of universal adhesive on enamel bond fatigue durability and interfacial characteristics with different etching modes. The three universal adhesives used were Scotchbond Universal Adhesive (3M ESPE, St Paul, MN, USA), Adhese Universal (Ivoclar Vivadent, Schaan, Lichtenstein), and G-Premio Bond (GC, Tokyo, Japan). The initial shear bond strength and shear fatigue strength to enamel was determined in the presence and absence of the oxygen inhibition layer, with and without phosphoric acid pre-etching. The water contact angle was also measured in all groups using the sessile drop method. The enamel bonding specimens with an oxygen inhibition layer showed significantly higher (padhesive type and etching mode. Moreover, the water contact angles on the specimens with an oxygen inhibition layer were significantly lower (puniversal adhesives significantly increases the enamel bond fatigue durability and greatly changes interfacial characteristics, suggesting that the bond fatigue durability and interfacial characteristics of these adhesives strongly rely on its presence.

Influence of Conditioning Time of Universal Adhesives on Adhesive Properties and Enamel-Etching Pattern.

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Cardenas, A M; Siqueira, F; Rocha, J; Szesz, A L; Anwar, M; El-Askary, F; Reis, A; Loguercio, A

2016-01-01

To evaluate the effect of application protocol in resin-enamel microshear bond strength (μSBS), in situ degree of conversion, and etching pattern of three universal adhesive systems. Sixty-three extracted third molars were sectioned in four parts (buccal, lingual, and proximals) and divided into nine groups, according to the combination of the main factors-Adhesive (Clearfil Universal, Kuraray Noritake Dental Inc, Tokyo, Japan; Futurabond U, VOCO, Cuxhaven, Germany; and Scotchbond Universal Adhesive, 3M ESPE, St Paul, MN, USA)-and enamel treatment/application time (etch-and-rinse mode [ER], self-etch [SE] application for 20 seconds [SE20], and SE application for 40 seconds [SE40]). Specimens were stored in water (37°C/24 h) and tested at 1.0 mm/min (μSBS). The degree of conversion of the adhesives at the resin-enamel interfaces was evaluated using micro-Raman spectroscopy. The enamel-etching pattern was evaluated under a scanning electron microscope. Data were analyzed with two-way analysis of variance and Tukey test (α=0.05). In general, the application of the universal adhesives in the SE40 produced μSBS and degree of conversion that were higher than in the SE20 (puniversal adhesives in the SE mode may be a viable alternative to increase the degree of conversion, etching pattern, and resin-enamel bond strength.

A New Approach to Amino Acid Racemization in Enamel: Testing of a Less Destructive Sampling Methodology.

NARCIS (Netherlands)

Griffin, R.C.; Moody, H.; Penkman, K.E.H.; Fagan, M.J.; Curtis, N.; Collins, M.J.

2008-01-01

Aspartic acid racemization has been found to be an accurate measure of age at death for recent forensic material. This paper examines the practicality of using acid etching of the tooth surface to extract amino acids from the enamel for racemization analysis. By serial etching of the tooth and

Effect of Storage Time on Bond Strength and Nanoleakage Expression of Universal Adhesives Bonded to Dentin and Etched Enamel.

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Makishi, P; André, C B; Ayres, Apa; Martins, A L; Giannini, M

2016-01-01

To investigate bond strength and nanoleakage expression of universal adhesives (UA) bonded to dentin and etched enamel. Extracted human third molars were sectioned and ground to obtain flat surfaces of dentin (n = 36) and enamel (n = 48). Dentin and etched enamel surfaces were bonded with one of two UAs, All-Bond Universal (ABU) or Scotchbond Universal (SBU); or a two-step self-etching adhesive, Clearfil SE Bond (CSEB). A hydrophobic bonding resin, Adper Scotchbond Multi-Purpose Bond (ASMP Bond) was applied only on etched enamel. Following each bonding procedure, resin composite blocks were built up incrementally. The specimens were sectioned and subjected to microtensile bond strength (MTBS) testing after 24 hours or one year water storage, or immersed into ammoniacal silver nitrate solution after aging with 10,000 thermocycles and observed using scanning electron microscopy. The percentage distribution of silver particles at the adhesive/tooth interface was calculated using digital image-analysis software. The MTBS (CSEB = SBU > ABU, for dentin; and CSEB > ABU = SBU = ASMP Bond, for etched enamel) differed significantly between the adhesives after 24 hours. After one year, MTBS values were reduced significantly within the same adhesive for both substrates (analysis of variance, Bonferroni post hoc, padhesives for etched enamel. Silver particles could be detected within the adhesive/dentin interface of all specimens tested. Kruskal-Wallis mean ranks for nanoleakage in ABU, SBU, and CSEB were 16.9, 18.5 and 11, respectively (p>0.05). In the short term, MTBS values were material and dental-substrate dependent. After aging, a decrease in bonding effectiveness was observed in all materials, with nanoleakage at the adhesive/dentin interface. The bonding of the UAs was equal or inferior to that of the conventional restorative systems when applied to either substrate and after either storage period.

Fluoride uptake from restorative dental materials by human enamel

International Nuclear Information System (INIS)

Forsten, L.; Rytoemaa, I.; Anttila, A.; Keinonen, J.

1976-01-01

The purpose of the study was to determine the uptake in vitro of fluoride from restorative materials by tooth enamel and whether prior etching of the enamel causes a change of uptake. The outermost layer of the labial surface of extracted canines was removed by grinding and the enamel was covered with five different fluoride-containing materials ; a silicate, a composite resin, an amalgam, a silicophosphate, and a polycarboxylate luting cement. The material was either removed immediately or after storing the tooth in distilled water. The fluoride content was determined using a sensitive physical method based on the 19 F (p, αγ) 16 O reaction. In addition, the fluoride content of enamel after etching for different periods of time and of etched enamel which had been in contact with silicate cement was determined. The mean fluoride content of uncovered interior enamel was 226 parts 10 6 . All materials, except the composite, increased clearly the fluoride content of the underlying enamel. Etching of interior enamel also increased the fluoride values. No difference could be shown in fluoride uptake from silicate and composite resin between etched and unetched enamel. (author)

A comparative study of different bleaching agents on the morphology of human enamel: an in vitro SEM study.

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Uthappa, Roshan; Suprith, M L; Bhandary, Shreetha; Dash, Sumit

2012-11-01

The purpose of the study was to compare two different commercial bleaching agents, Opalescence with Colgate Platinum, and 30% phosphoric acid used as aggressive agent on the morphology of human enamel. Ten freshly extracted, noncarious, human maxillary central incisors extracted for periodontal reasons were used in this study. The labial surface of the disinfected teeth were polished using a polishing paste with the help of rubber cup and a slow speed handpiece. Each tooth was sectioned at cement-enamel junction and the crown was separated into four specimens, all taken from labial surface. Group 1 was treated with Colgate Platinum for 7 hours, group 2 with Opalescence for 7 hours, group 3 was treated with 30% phosphoric acid for 30 seconds and group 4 was untreated and used as control. After the treatment period, the specimens were washed with normal saline and stored in sterile bottle and sealed. Photomicrographs obtained from the scanning electron microscopy (SEM) after surface treatments were examined for no alteration, slight alteration, moderate alteration and severe alterations. The specimens treated with commercial bleaching agents revealed no enamel surface morphologic alterations compared to control group. The specimen treated with phosphoric acid showed severe alterations. Ten percent carbamide peroxide evaluated in this study does not etch tooth enamel or alter enamel surface morphology as do conventional etching techniques. Carbamine peroxide is a safe and effective tooth whitening agent even when used for extended period of time. The enamel surface remains smooth which reduces caries due to plaque collection.

Comparison of shear bond strength of self-etch and self-adhesive cements bonded to lithium disilicate, enamel and dentin.

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Naranjo, Jennifer; Ali, Mohsin; Belles, Donald

2015-11-01

Comparison of shear bond strength of self-etch and self-adhesive cements bonded to lithium disilicate, enamel and dentin. With several self-adhesive resin cements currently available, there is confusion about which product and technique is optimal for bonding ceramic restorations to teeth. The objective of this study was to compare the shear bond strength of lithium disilicate cemented to enamel and dentin using 5 adhesive cements. 100 lithium disilicate rods were pretreated with 5% hydrofluoric acid, silane, and cemented to 50 enamel and 50 dentin surfaces using five test cements: Variolink II (etch-and-rinse) control group, Clearfil Esthetic (two step self-etch), RelyX Unicem, SpeedCEM, and BifixSE (self-adhesive). All specimens were stored (37 degrees C, 100% humidity) for 24 hours before testing their shear bond strength using a universal testing machine (Instron). Debonded surfaces were observed under a low-power microscope to assess the location and type of failure. The highest bond strength for both enamel and dentin were recorded for Variolink II, 15.1MPa and 20.4MPa respectively, and the lowest were recorded for BifixSE, 0.6MPa and 0.9MPa respectively. Generally, higher bond strengths were found for dentin (7.4MPa) than enamel (5.3MPa). Tukey's post hoc test showed no significant difference between Clearfil Esthetic and SpeedCem (p = 0.059), Unicem and SpeedCem (p = 0.88), and Unicem and BifixSE (p = 0.092). All cements bonded better to lithium disilicate than to enamel or dentin, as all bond failures occurred at the tooth/adhesive interface except for Variolink II. Bond strengths recorded for self-adhesive cements were very low compared to the control "etch and rinse" and self-etch systems. Further improvements are apparently needed in self-adhesive cements for them to replace multistep adhesive systems. The use of conventional etch and rinse cements such as Veriolink II should be preferred for cementing all ceramic restorations over self-adhesive cements

The effects of three different food acids on the attrition-corrosion wear of human dental enamel

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Zhang, Yichi; Arsecularatne, Joseph A.; Hoffman, Mark

2015-07-01

With increased consumption of acidic drinks and foods, the wear of human teeth due to attrition in acidic environments is an increasingly important issue. Accordingly, the present paper investigates in vitro the wear of human enamel in three different acidic environments. Reciprocating wear tests in which an enamel cusp slides on an enamel flat surface were carried out using acetic, citric and lactic acid lubricants (at pH 3-3.5). Distilled water was also included as a lubricant for comparison. Focused ion beam milling and scanning electron microscopy imaging were then used to investigate the enamel subsurfaces following wear tests. Nanoindentation was used to ascertain the changes in enamel mechanical properties. The study reveals crack generation along the rod boundaries due to the exposure of enamel to the acidic environments. The wear mechanism changes from brittle fracture in distilled water to ploughing or shaving of the softened layer in acidic environments, generating a smooth surface with the progression of wear. Moreover, nanoindentation results of enamel samples which were exposed to the above acids up to a duration of the wear tests show decreasing hardness and Young’s modulus with exposure time.

An evaluation of shear bond strength of self-etch adhesive on pre-etched enamel: an in vitro study.

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Rao, Bhadra; Reddy, Satti Narayana; Mujeeb, Abdul; Mehta, Kanchan; Saritha, G

2013-11-01

To determine the shear bond strength of self-etch adhesive G-bond on pre-etched enamel. Thirty caries free human mandibular premolars extracted for orthodontic purpose were used for the study. Occlusal surfaces of all the teeth were flattened with diamond bur and a silicon carbide paper was used for surface smoothening. The thirty samples were randomly grouped into three groups. Three different etch systems were used for the composite build up: group 1 (G-bond self-etch adhesive system), group 2 (G-bond) and group 3 (Adper single bond). Light cured was applied for 10 seconds with a LED unit for composite buildup on the occlusal surface of each tooth with 8 millimeters (mm) in diameter and 3 mm in thickness. The specimens in each group were tested in shear mode using a knife-edge testing apparatus in a universal testing machine across head speed of 1 mm/ minute. Shear bond strength values in Mpa were calculated from the peak load at failure divided by the specimen surface area. The mean shear bond strength of all the groups were calculated and statistical analysis was carried out using one-way Analysis of Variance (ANOVA). The mean bond strength of group 1 is 15.5 Mpa, group 2 is 19.5 Mpa and group 3 is 20.1 Mpa. Statistical analysis was carried out between the groups using one-way ANOVA. Group 1 showed statistically significant lower bond strength when compared to groups 2 and 3. No statistical significant difference between groups 2 and 3 (p adhesive G-bond showed increase in shear bond strength on pre-etched enamel.

Effect of bracket bonding with Er: YAG laser on nanomechanical properties of enamel.

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Alavi, Shiva; Birang, Reza; Hajizadeh, Fatemeh; Banimostafaee, Hamed

2014-01-01

The aim of this study was to compare the effects of conventional acid etching and laser etching on the nano-mechanical properties of the dental enamel using nano-indentation test. In this experimental in vitro study, buccal surfaces of 10 premolars were divided into three regions. One of the regions was etched with 37% phosphoric acid and another etched with Er:YAG laser, the third region was not etched. The brackets were bonded to both of etched regions. After thermocycling for 500 cycles, the brackets were removed and the teeth were decoronated from the bracket bonding area. Seven nano-indentations were applied at 1-31 μm depth from the enamel surface in each region. Mean values of the hardness and elastic modulus were analyzed with repeated measures analysis of variance and Tukey HSD tests, using the SPSS software (SPSS Inc., version16.0, Chicago, Il, USA). P < 0.05 was considered as significant. The hardness up to 21 μm in depth and elastic modulus up to 6 μm in depth from the enamel surface for laser-etched enamel had significantly higher values than control enamel and the hardness up to 11 μm in depth and elastic modulus up to 6 μm in depth for acid-etched enamel had significantly lower values than the control enamel. The mechanical properties of the enamel were decreased after bracket bonding with conventional acid etching and increased after bonding with Er:YAG laser.

Effect of bracket bonding with Er: YAG laser on nanomechanical properties of enamel

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Shiva Alavi

2014-01-01

Full Text Available Background: The aim of this study was to compare the effects of conventional acid etching and laser etching on the nano-mechanical properties of the dental enamel using nano-indentation test. Materials and Methods: In this experimental in vitro study, buccal surfaces of 10 premolars were divided into three regions. One of the regions was etched with 37% phosphoric acid and another etched with Er:YAG laser, the third region was not etched. The brackets were bonded to both of etched regions. After thermocycling for 500 cycles, the brackets were removed and the teeth were decoronated from the bracket bonding area. Seven nano-indentations were applied at 1-31 μm depth from the enamel surface in each region. Mean values of the hardness and elastic modulus were analyzed with repeated measures analysis of variance and Tukey HSD tests, using the SPSS software (SPSS Inc., version16.0, Chicago, Il, USA. P < 0.05 was considered as significant. Results: The hardness up to 21 μm in depth and elastic modulus up to 6 μm in depth from the enamel surface for laser-etched enamel had significantly higher values than control enamel and the hardness up to 11 μm in depth and elastic modulus up to 6 μm in depth for acid-etched enamel had significantly lower values than the control enamel. Conclusion: The mechanical properties of the enamel were decreased after bracket bonding with conventional acid etching and increased after bonding with Er:YAG laser.

The use of a 'bleach-etch-seal' deproteinization technique on MIH affected enamel.

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Gandhi, Shan; Crawford, Peter; Shellis, Peter

2012-11-01

To ascertain whether deproteinization pretreatment of molar-incisor hypomineralization (MIH) enamel affects resin sealant infiltration. Thirty one extracted MIH teeth were divided into three sections and randomly allocated into the Control (etch and FS), Treatment 1 (5% NaOCl, etched and fissure sealed), and Treatment 2 (5% NaOCl and fissure sealed with no etch) groups. Two hundred seventy nine sealant tag/enamel grade observations were recorded by scanning electron microscopy. Control and Treatment 1 were similar in their outcomes, and Treatment 2 was markedly different. There was no statistical evidence to suggest that there was any difference between Treatment 1 and the Control Treatment (95% CI, 0.52, 1.51; P = 0.6). There was a marked difference between Treatment 2 and the Control Treatment (95% CI, 0.07, 0.25; P MIH enamel, regardless of which of the three treatments was used. © 2012 The Authors. International Journal of Paediatric Dentistry © 2012 BSPD, IAPD and Blackwell Publishing Ltd.

Influence of Application Time and Etching Mode of Universal Adhesives on Enamel Adhesion.

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Sai, Keiichi; Takamizawa, Toshiki; Imai, Arisa; Tsujimoto, Akimasa; Ishii, Ryo; Barkmeier, Wayne W; Latta, Mark A; Miyazaki, Masashi

2018-01-01

To investigate the influence of application time and etching mode of universal adhesives on enamel adhesion. Five universal adhesives, Adhese Universal, Bondmer Lightless, Clearfil Universal Bond Quick, G-Premio Bond, and Scotchbond Universal, were used. Bovine incisors were prepared and divided into four groups of ten teeth each. SBS, Ra, and SFE were determined after the following procedures: 1. self-etch mode with immediate air blowing after application (IA); 2. self-etch mode with prolonged application time (PA); 3. etch-and-rinse mode with IA; 4. etch-and-rinse mode with PA. After 24-h water storage, the bonded assemblies were subjected to shear bond strength (SBS) tests. For surface roughness (Ra) and surface free energy (SFE) measurements, the adhesives were simply applied to the enamel and rinsed with acetone and water before the measurements were carried out. Significantly higher SBS and Ra values were obtained with etch-and-rinse mode than with self-etch mode regardless of the application time or type of adhesive. Although most adhesives showed decreased SFE values with increased application time in self-etch mode, SFE values in etch-and-rinse mode were dependent on the adhesive type and application time. Etching mode, application time, and type of adhesive significantly influenced the SBS, Ra, and SFE values.

Influence of frequency on shear fatigue strength of resin composite to enamel bonds using self-etch adhesives.

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Takamizawa, Toshiki; Scheidel, Donal D; Barkmeier, Wayne W; Erickson, Robert L; Tsujimoto, Akimasa; Latta, Mark A; Miyazaki, Masashi

2016-09-01

The purpose of this study was to determine the influence of different frequency rates on of bond durability of self-etch adhesives to enamel using shear fatigue strength (SFS) testing. A two-step self-etch adhesive (OX, OptiBond XTR), and two single step self-etch adhesives (GB, G-ӕnial Bond and SU, Scotchbond Universal) were used in this study. The shear fatigue strength (SFS) to enamel was obtained. A staircase method was used to determine the SFS values with 50,000 cycles or until failure occurred. Fatigue testing was performed at frequencies of 5Hz, 10Hz, and 20Hz. For each test condition, 30 specimens were prepared for the SFS testing. Regardless of the bond strength test method, OX showed significantly higher SFS values than the two single-step self-etch adhesives. For each of the three individual self-etch adhesives, there was no significant difference in SFS depending on the frequency rate, although 20Hz results tended to be higher. Regardless of the self-etch adhesive system, frequencies of 5Hz, 10Hz, and 20Hz produced similar results in fatigue strength of resin composite bonded to enamel using 50,000 cycles or until bond failure. Accelerated fatigue testing provides valuable information regarding the long term durability of resin composite to enamel bonding using self-etch adhesive system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of CPP-ACP on the remineralization of acid-eroded human tooth enamel: nanomechanical properties and microtribological behaviour study

International Nuclear Information System (INIS)

Zheng, L; Zheng, J; Zhang, Y F; Qian, L M; Zhou, Z R

2013-01-01

Casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP) has been used to enhance tooth remineralization in the dental clinic. But the contribution of CPP-ACP to the remineralization of acid-eroded human tooth enamel is of widespread controversy. To confirm the application potential of CPP-ACP in the remineralization repair of tooth erosion caused by acid-attack, the effect of remineralization in vitro in 2% w/v CPP-ACP solution on the acid-eroded human tooth enamel was investigated in this study. The repair of surface morphology and the improvement of nanomechanical and microtribological properties were characterized with laser confocal scanning microscope, scanning electron microscope, nanoindentation tester and nanoscratch tester. Results showed that a layer of uneven mineral deposits, which were mainly amorphous calcium phosphate (ACP) in all probability, was observed on the acid-eroded enamel surface after remineralization. Compared with the acid-eroded enamel surface, the nanoindentation hardness and Young's modulus of the remineralized enamel surface obviously increased. Both the friction coefficient and wear volume of the acid-eroded enamel surface decreased after remineralization. However, both the nanomechanical and the anti-wear properties of the remineralized enamel surface were still inferior to those of original enamel surface. In summary, tooth damage caused by acid erosion could be repaired by remineralization in CPP-ACP solution, but the repair effect, especially on the nanomechanical and anti-wear properties of the acid-eroded enamel, was limited. These results would contribute to a further exploration of the remineralization potential of CPP-ACP and a better understanding of the remineralization repair mechanism for acid-eroded human tooth enamel. (paper)

Effect of CPP-ACP on the remineralization of acid-eroded human tooth enamel: nanomechanical properties and microtribological behaviour study

Science.gov (United States)

Zheng, L.; Zheng, J.; Zhang, Y. F.; Qian, L. M.; Zhou, Z. R.

2013-10-01

Casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP) has been used to enhance tooth remineralization in the dental clinic. But the contribution of CPP-ACP to the remineralization of acid-eroded human tooth enamel is of widespread controversy. To confirm the application potential of CPP-ACP in the remineralization repair of tooth erosion caused by acid-attack, the effect of remineralization in vitro in 2% w/v CPP-ACP solution on the acid-eroded human tooth enamel was investigated in this study. The repair of surface morphology and the improvement of nanomechanical and microtribological properties were characterized with laser confocal scanning microscope, scanning electron microscope, nanoindentation tester and nanoscratch tester. Results showed that a layer of uneven mineral deposits, which were mainly amorphous calcium phosphate (ACP) in all probability, was observed on the acid-eroded enamel surface after remineralization. Compared with the acid-eroded enamel surface, the nanoindentation hardness and Young's modulus of the remineralized enamel surface obviously increased. Both the friction coefficient and wear volume of the acid-eroded enamel surface decreased after remineralization. However, both the nanomechanical and the anti-wear properties of the remineralized enamel surface were still inferior to those of original enamel surface. In summary, tooth damage caused by acid erosion could be repaired by remineralization in CPP-ACP solution, but the repair effect, especially on the nanomechanical and anti-wear properties of the acid-eroded enamel, was limited. These results would contribute to a further exploration of the remineralization potential of CPP-ACP and a better understanding of the remineralization repair mechanism for acid-eroded human tooth enamel.

Preliminary surface analysis of etched, bleached, and normal bovine enamel

International Nuclear Information System (INIS)

Ruse, N.D.; Smith, D.C.; Torneck, C.D.; Titley, K.C.

1990-01-01

X-ray photoelectron spectroscopic (XPS) and secondary ion-mass spectroscopic (SIMS) analyses were performed on unground un-pumiced, unground pumiced, and ground labial enamel surfaces of young bovine incisors exposed to four different treatments: (1) immersion in 35% H2O2 for 60 min; (2) immersion in 37% H3PO4 for 60 s; (3) immersion in 35% H2O2 for 60 min, in distilled water for two min, and in 37% H3PO4 for 60 s; (4) immersion in 37% H3PO4 for 60 s, in distilled water for two min, and in 35% H2O2 for 60 min. Untreated unground un-pumiced, unground pumiced, and ground enamel surfaces, as well as synthetic hydroxyapatite surfaces, served as controls for intra-tooth evaluations of the effects of different treatments. The analyses indicated that exposure to 35% H2O2 alone, besides increasing the nitrogen content, produced no other significant change in the elemental composition of any of the enamel surfaces investigated. Exposure to 37% H3PO4, however, produced a marked decrease in calcium (Ca) and phosphorus (P) concentrations and an increase in carbon (C) and nitrogen (N) concentrations in unground un-pumiced specimens only, and a decrease in C concentration in ground specimens. These results suggest that the reported decrease in the adhesive bond strength of resin to 35% H2O2-treated enamel is not caused by a change in the elemental composition of treated enamel surfaces. They also suggest that an organic-rich layer, unaffected by acid-etching, may be present on the unground un-pumiced surface of young bovine incisors. This layer can be removed by thorough pumicing or by grinding. An awareness of its presence is important when young bovine teeth are used in a model system for evaluation of resin adhesiveness

Influence of water storage on fatigue strength of self-etch adhesives.

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Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Scheidel, Donal D; Watanabe, Hidehiko; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

2015-12-01

The purpose of this study was to determine enamel and dentin bond durability after long-term water storage using self-etch adhesives. Two single step self-etch adhesives (SU, Scotchbond Universal and GB, G-ӕnial Bond) and a two-step self-etch adhesive (OX, OptiBond XTR) were used. The shear bond strength (SBS) and shear fatigue strength (FS) of the enamel and dentin were obtained with and without phosphoric acid pre-etching prior to application of the adhesives. The specimens were stored in distilled water at 37 °C for 24 h, 6 months, and one year. A staircase method was used to determine the FS using a frequency of 10 Hz for 50,000 cycles or until failure occurred. The SBS and FS of enamel bonds were significantly higher with pre-etching, when compared to no pre-etching for the same water storage period. The FS of dentin bonds with pre-etching tended to decrease relative to no pre-etching at the same storage period. For the one year storage period, SU and GB with pre-etching showed significantly lower FS values than the groups without pre-etching. The influence of water storage on FS of the self-etch adhesives was dependent on the adhesive material, storage period and phosphoric acid pre-etching of the bonding site. Phosphoric acid pre-etching of enamel improves the effectiveness of self-etch adhesive systems. Inadvertent contact of phosphoric acid on dentin appears to reduce the ability of self-etch adhesives to effectively bond resin composite materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of enamel conditioning on the shear bond strength of different adhesives.

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Brauchli, Lorenz; Muscillo, Teodoro; Steineck, Markus; Wichelhaus, Andrea

2010-11-01

Phosphoric acid etching is the gold standard for enamel conditioning. However, it is possible that air abrasion or a combination of air abrasion and etching might result in enhanced adhesion. The aim of this study was to investigate the effect of different enamel conditioning methods on the bond strength of six adhesives. Three different enamel conditioning procedures (phosphoric acid etching, air abrasion, air abrasion + phosphoric acid etching) were evaluated for their influence on the shear bond strength of six different adhesives (Transbond™ XT, Cool-Bond™, Fuji Ortho LC, Ultra Band-Lok, Tetric(®) Flow, Light-Bond™). Each group consisted of 15 specimens. Shear forces were measured with a universal testing machine. The scores of the Adhesive Remnant Index (ARI) were also analyzed. There were no significant differences between phosphoric acid etching and air abrasion + phosphoric acid etching. Air abrasion as a single conditioning technique led to significantly lower shear forces. The ARI scores did not correlate with the shear strengths measured. There were greater variations in shear forces for the different adhesives than for the conditioning techniques. The highest shear forces were found for the conventional composites Transbond™ XT and Cool- Bond™ in combination with conventional etching. Air abrasion alone and in combination with phosphoric acid etching showed no advantages compared with phosphoric acid etching alone and, therefore, cannot be recommended.

Relationship between enamel bond fatigue durability and surface free-energy characteristics with universal adhesives.

Science.gov (United States)

Nagura, Yuko; Tsujimoto, Akimasa; Barkmeier, Wayne W; Watanabe, Hidehiko; Johnson, William W; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2018-04-01

The relationship between enamel bond fatigue durability and surface free-energy characteristics with universal adhesives was investigated. The initial shear bond strengths and shear fatigue strengths of five universal adhesives to enamel were determined with and without phosphoric acid pre-etching. The surface free-energy characteristics of adhesive-treated enamel with and without pre-etching were also determined. The initial shear bond strength and shear fatigue strength of universal adhesive to pre-etched enamel were higher than those to ground enamel. The initial shear bond strength and shear fatigue strength of universal adhesive to pre-etched enamel were material dependent, unlike those to ground enamel. The surface free-energy of the solid (γ S ) and the hydrogen-bonding force (γSh) of universal adhesive-treated enamel were different depending on the adhesive, regardless of the presence or absence of pre-etching. The bond fatigue durability of universal adhesives was higher to pre-etched enamel than to ground enamel. In addition, the bond fatigue durability to pre-etched enamel was material dependent, unlike that to ground enamel. The surface free-energy characteristics of universal adhesive-treated enamel were influenced by the adhesive type, regardless of the presence or absence of pre-etching. The surface free-energy characteristics of universal adhesive-treated enamel were related to the results of the bond fatigue durability. © 2018 Eur J Oral Sci.

Laser investigation of the non-uniformity of fluorescent species in dental enamel

Science.gov (United States)

Tran, Stephanie U.; Ridge, Jeremy S.; Nelson, Leonard Y.; Seibel, Eric J.

In the present study, artificial type I and type II erosions were created on dental specimen using acetic acid and EDTA respectively. Specimens were prepared by etching extracted teeth samples in acid to varying degrees, after which the absolute fluorescence intensity ratio of the etched enamel relative to sound enamel was recorded for each specimen using 405 and 532 nm laser excitation. Results showed differences in the fluorescence ratio of etched to sound enamel for type I and II erosions. These findings suggest a non-uniform distribution of fluorescent species in the interprismatic region as compared to the prismatic region.

Comparative study of etched enamel and dentin for the adhesion of composite resins with the Er:YAG 2,94 μm laser and CO2 9,6 μm laser: morphological (SEM) and tensile bond strength analysis

International Nuclear Information System (INIS)

Marraccini, Tarso Mugnai

2002-01-01

The aim of this study was to evaluate and compare the tensile bond strength of a composite resin adhered to the enamel and dentin which have received superficial irradiation with an Er:YAG laser (2.94 μm) or with CO 2 laser ( 9.6 μm) and later on etched with the phosphoric acid at 35%. After the use of the adhesive system, resin cones were made on the etched surfaces by both lasers and tensile bond strength tests were performed. All samples were observed at the SEM - there was an increase of the degree of fusion and resolidification in the irradiated enamel and dentin samples with the CO 2 laser (9.6 μm), creating a vitrified layer with tiny craters. With the Er:YAG laser (2.94 μm) there were typical morphological explosive microablation with the exposition of the tubules in the dentin.The surface acquired by the association of the CO 2 laser ( 9.6 μm) plus acid etching no longer presented the aspect of fusion being this layer completely removed. There were statistical significant differences among ali three methods of etching in the treatment of the enamel and dentin surface. The tensile bond strength test showed that etching of these enamel and dentin surfaces with acid exclusively (control group) presented great values, surpassing the values of the etching acquired with the Er:YAG laser (2.94 μ) plus acid or the CO 2 laser (9.6 μm) plus acid. With the parameters used in this experiment the Er:YAG laser (2.94 μm) showed to be more effective than the CO 2 laser (9.6 μm) for the hard dental surfaces etching procedure. (author)

Effects of a non-rinse conditioner on the enamel of primary teeth

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Fava Marcelo

2003-01-01

Full Text Available The aim of this in vitro study was to evaluate by scanning electron microscopy the morphological aspects of the enamel of primary teeth after etching with 36% phosphoric acid or a non-rinse conditioner. Ten naturally exfoliated anterior primary teeth were selected. The samples were subjected to prophylaxis with pumice paste and water using a low-speed hand piece. Etching was done on the buccal surface. Specimens were divided into 2 groups: G1 (n=10: etching with 36% phosphoric acid gel - Conditioner 36 (Dentsply for 20 s, followed by water rinse for 15 s; G2 (n=10: etching with NRC - Non Rinse Conditioner (Dentsply for 20 s, followed by air drying for 15 s. The samples were dehydrated, mounted on metal stubs, coated with gold and observed with Jeol JSM-6100 scanning electron microscope. Electron-micrographic analysis showed that both etching agents were effective for etching the enamel of primary teeth causing the formation of microporosities on the enamel surface, although the etching pattern was more effective with the use of 36% phosphoric acid gel.

Measurement of the efficacy of calcium silicate for the protection and repair of dental enamel.

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Parker, Alexander S; Patel, Anisha N; Al Botros, Rehab; Snowden, Michael E; McKelvey, Kim; Unwin, Patrick R; Ashcroft, Alexander T; Carvell, Mel; Joiner, Andrew; Peruffo, Massimo

2014-06-01

To investigate the formation of hydroxyapatite (HAP) from calcium silicate and the deposition of calcium silicate onto sound and acid eroded enamel surfaces in order to investigate its repair and protective properties. Calcium silicate was mixed with phosphate buffer for seven days and the resulting solids analysed for crystalline phases by Raman spectroscopy. Deposition studies were conducted on bovine enamel surfaces. Acid etched regions were produced on the enamel surfaces using scanning electrochemical cell microscopy (SECCM) with acid filled pipettes and varying contact times. Following treatment with calcium silicate, the deposition was visualised with FE-SEM and etch pit volumes were measured by AFM. A second set of bovine enamel specimens were pre-treated with calcium silicate and fluoride, before acid exposure with the SECCM. The volumes of the resultant acid etched pits were measured using AFM and the intrinsic rate constant for calcium loss was calculated. Raman spectroscopy confirmed that HAP was formed from calcium silicate. Deposition studies demonstrated greater delivery of calcium silicate to acid eroded than sound enamel and that the volume of acid etched enamel pits was significantly reduced following one treatment (penamel was 0.092 ± 0.008 cm/s. This was significantly reduced, 0.056 ± 0.005 cm/s, for the calcium silicate treatments (penamel surfaces. Calcium silicate can provide significant protection of sound enamel from acid challenges. Calcium silicate is a material that has potential for a new approach to the repair of demineralised enamel and the protection of enamel from acid attacks, leading to significant dental hard tissue benefits. © 2014 Elsevier Ltd. All rights reserved.

Does ErbiumiYttrium-Aluminum-Garnet Laser to Enamel improve the Performance of Etch-and-rinse and Universal Adhesives?

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De Jesus Tavarez, Rudys R; Rodrigues, Lorrany Lc; Diniz, Ana C; Lage, Lucas M; Torres, Carlos Rg; Bandeca, Matheus C; Firoozmand, Leily M

2018-03-01

This study aims to evaluate the effect of erbium: Yttrium-aluminum-garnet (Er:YAG) laser irradiation on the enamel microshear bond strength (μSBS), followed by the utilization of etch-and-rinse and universal adhesive systems. A total of 32 molars were sectioned in the mesiodistal direction producing 64 samples that were randomized into two groups (n = 32): single bond 2 (SB2) (etch-and-rinse system; 3M), SB universal (SBU) (universal etching system; The SB2 and SBU groups were then divided into two subgroups (n = 16): (i) enamel was irradiated with an Er:YAG laser (λ = 2.94 μm, 60 mJ, 10 Hz), and (ii) enamel served as a control. The samples were restored with TPH3 (Dentsply), stored in artificial saliva for 24 hours, and subjected to a micro-shear test. Kruskal-Wallis (p enamel interface. The previous irradiation of enamel with Er:YAG laser does not interfere with the performance of simplified two-step etch-and-rinse and universal adhesive systems. The increasing use of Er:YAG laser is important to evaluate the influence of this irradiation on the adhesion of restorative materials. Thus, to obtain the longevity of the restorative procedures, it is necessary to know the result of the association of the present adhesive systems to the irradiated substrate.

Bonding performance of universal adhesives to er,cr:YSGG laser-irradiated enamel.

Science.gov (United States)

Ayar, Muhammet Kerim; Erdemir, Fatih

2017-04-01

Universal adhesives have been recently introduced for use as self-etch or etch-and-rinse adhesives depending on the dental substrate and clinical condition. However, their bonding effectiveness to laser-irradiated enamel is still not well-known. Thus, the aim of this study was to compare the shear bond strength (SBS) of universal adhesives (Single Bond Universal; Nova Compo-B Plus) applied to Er,Cr:YSGG laser-irradiated enamel with SBS of the same adhesives applied in self-etch and acid-etching modes, respectively. Crown segments of sixty bovine incisors were embedded into standardized acrylic blocks. Flattened enamel surfaces were prepared. Specimens were divided into six groups according to universal adhesives and application modes randomly (n = 10), as follows: Single Bond Universal/acid-etching mode; Nova Compo-B Plus/acid-etching mode; Single Bond Universal/self-etching mode; Nova Compo-B Plus/self-etching mode; and Single Bond Universal/Er,Cr:YSGG Laser-etching mode; Nova Compo-B Plus/Er,Cr:YSGG Laser-etching mode. After surface treatments, universal adhesives were applied onto surfaces. SBS was determined after storage in water for 24 h using a universal testing machine with a crosshead speed of 0.5 mm min -1 . Failure modes were evaluated using a stereomicroscope. Data was analyzed using two-way of analyses of variances (ANOVA) (p = 0.05). Two-way ANOVA revealed that adhesive had no effect on SBS (p = 0.88), but application mode significantly influenced SBS (p = 0.00). Acid-etching significantly increased SBS, whereas there are no significant differences between self-etch mode and laser-etching for both adhesives. The bond strength of universal adhesives may depend on application mode. Acid etching may significantly increase bond strength, while laser etching may provide similar bond strength when compared to self-etch mode. © 2016 Wiley Periodicals, Inc.

Shear bond strength of composite bonded with three adhesives to Er,Cr:YSGG laser-prepared enamel.

Science.gov (United States)

Türkmen, Cafer; Sazak-Oveçoğlu, Hesna; Günday, Mahir; Güngör, Gülşad; Durkan, Meral; Oksüz, Mustafa

2010-06-01

To assess in vitro the shear bond strength of a nanohybrid composite resin bonded with three adhesive systems to enamel surfaces prepared with acid and Er,Cr:YSGG laser etching. Sixty extracted caries- and restoration-free human maxillary central incisors were used. The teeth were sectioned 2 mm below the cementoenamel junction. The crowns were embedded in autopolymerizing acrylic resin with the labial surfaces facing up. The labial surfaces were prepared with 0.5-mm reduction to receive composite veneers. Thirty specimens were etched with Er,Cr:YSGG laser. This group was also divided into three subgroups, and the following three bonding systems were then applied on the laser groups and the other three unlased groups: (1) 37% phosphoric acid etch + Bond 1 primer/adhesive (Pentron); (2) Nano-bond self-etch primer (Pentron) + Nano-bond adhesive (Pentron); and (3) all-in-one adhesive-single dose (Futurabond NR, Voco). All of the groups were restored with a nanohybrid composite resin (Smile, Pentron). Shear bond strength was measured with a Zwick universal test device with a knife-edge loading head. The data were analyzed with two-factor ANOVA. There were no significant differences in shear bond strength between self-etch primer + adhesive and all-in-one adhesive systems for nonetched and laser-etched enamel groups (P > .05). However, bond strength values for the laser-etched + Bond 1 primer/adhesive group (48.00 +/- 13.86 MPa) were significantly higher than the 37% phosphoric acid + Bond 1 primer/adhesive group (38.95 +/- 20.07 MPa) (P enamel surface more effectively than 37% phosphoric acid for subsequent attachment of composite material.

Marginal microleakage in vitro study on class V cavities prepared with Er:YAG laser and etched with acid or etched with Er:YAG laser and acid

International Nuclear Information System (INIS)

Tavares, Henrique Dutra Simoes

2001-01-01

Microleakage at the interface between the teeth and the restorative materials remains a problem with composite resin restorations. Microleakage at the gingival margins of class V cavities restorations still challenge as they are usually placed in dentin and/or cementum. Previous studies have shown that the cavity preparation with Er:YAG laser is possible. It has been reported that Er:YAG laser has ability to create irregular surface providing micromechanical retention for adhesive dental restorative materials and to improve marginal sealing. The purpose of this in vitro study was to evaluate the marginal microleakage on class V cavities prepared with Er:YAG laser and etched with acid or with Er:YAG laser and acid, in compared to those prepared and etched conventionally. Thirty human molars were divided into three groups, namely: group I - prepared with Er:YAG laser (KaVo KEY Laser II - Germany) and etched with 37% phosphoric acid; group II - prepared with Er:YAG laser and etched with Er:YAG laser and 37% phosphoric acid; group III (control group) - prepared with high speed drill and etched with 37% phosphoric acid. All cavities were treated with same adhesive system (Single Bond - 3M) and restored with the composite resin (Z100 - 3M), according to the manufacturer's instructions. The specimens were stored at 37 deg C in water for 24 hours, polished with Sof-Lex discs (3M), thermally stressed, sealed with a nail polish coating except for the area of the restoration and 1 mm around it, and immersed in a 50% aqueous solution of silver nitrate for 24 hours. After that, the specimens were rinsed in water, soaked in a photodeveloping solution and exposed to a fluorescent light for 8 hours. The teeth were embedded in an autopolymerizing resin and sectioned longitudinally using a diamond saw microtome under running water. The sections were photographed. The microleakage at the occlusal cavity and at the gingival margins of each specimen was evaluated with scores (0-3) by

Enamel Bond Strength of New Universal Adhesive Bonding Agents.

Science.gov (United States)

McLean, D E; Meyers, E J; Guillory, V L; Vandewalle, K S

2015-01-01

Universal bonding agents have been introduced for use as self-etch or etch-and-rinse adhesives depending on the dental substrate and clinician's preference. The purpose of this study was to evaluate the shear bond strength (SBS) of composite to enamel using universal adhesives compared to a self-etch adhesive when applied in self-etch and etch-and-rinse modes over time. Extracted human third molars were used to create 120 enamel specimens. The specimens were ground flat and randomly divided into three groups: two universal adhesives and one self-etch adhesive. Each group was then subdivided, with half the specimens bonded in self-etch mode and half in etch-and-rinse mode. The adhesives were applied as per manufacturers' instructions, and composite was bonded using a standardized mold and cured incrementally. The groups were further divided into two subgroups with 10 specimens each. One subgroup was stored for 24 hours and the second for six months in 37°C distilled water and tested in shear. Failure mode was also determined for each specimen. A three-way analysis of variance (ANOVA) found a significant difference between groups based on bonding agent (p0.05). Clearfil SE in etch-and-rinse and self-etch modes had more mixed fractures than either universal adhesive in either mode. Etching enamel significantly increased the SBS of composite to enamel. Clearfil SE had significantly greater bond strength to enamel than either universal adhesive, which were not significantly different from each other.

Effect of a functional monomer (MDP) on the enamel bond durability of single-step self-etch adhesives.

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Tsuchiya, Kenji; Takamizawa, Toshiki; Barkmeier, Wayne W; Tsubota, Keishi; Tsujimoto, Akimasa; Berry, Thomas P; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

2016-02-01

The present study aimed to determine the effect of the functional monomer, 10-methacryloxydecyl dihydrogen phosphate (MDP), on the enamel bond durability of single-step self-etch adhesives through integrating fatigue testing and long-term water storage. An MDP-containing self-etch adhesive, Clearfil Bond SE ONE (SE), and an experimental adhesive, MDP-free (MF), which comprised the same ingredients as SE apart from MDP, were used. Shear bond strength (SBS) and shear fatigue strength (SFS) were measured with or without phosphoric acid pre-etching. The specimens were stored in distilled water for 24 h, 6 months, or 1 yr. Although similar SBS and SFS values were obtained for SE with pre-etching and for MF after 24 h of storage in distilled water, SE with pre-etching showed higher SBS and SFS values than MF after storage in water for 6 months or 1 yr. Regardless of the pre-etching procedure, SE showed higher SBS and SFS values after 6 months of storage in distilled water than after 24 h or 1 yr. To conclude, MDP might play an important role in enhancing not only bond strength but also bond durability with respect to repeated subcritical loading after long-term water storage. © 2015 Eur J Oral Sci.

Influence of the number of cycles on shear fatigue strength of resin composite bonded to enamel and dentin using dental adhesives in self-etching mode.

Science.gov (United States)

Tsujimoto, Akimasa; Barkmeier, Wayne W; Erickson, Robert L; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2018-01-30

The influence of the number of cycles on shear fatigue strength to enamel and dentin using dental adhesives in self-etch mode was investigated. A two-step self-etch adhesive and two universal adhesives were used to bond to enamel and dentin in self-etch mode. Initial shear bond strength and shear fatigue strength to enamel and dentin using the adhesive in self-etch mode were determined. Fatigue testing was used with 20 Hz frequency and cycling periods of 50,000, 100,000 and 1,000,000 cycles, or until failure occurred. For each of the cycling periods, there was no significant difference in shear fatigue strength across the cycling periods for the individual adhesives. Differences in shear fatigue strength were found between the adhesives within the cycling periods. Regardless of the adhesive used in self-etch mode for bonding to enamel or dentin, shear fatigue strength was not influenced by the number of cycles used for shear fatigue strength testing.

Comparative Evaluation of Shear Bond Strength of Orthodontic Brackets using Laser Etching and Two Conventional Etching Techniques: An in vitro Study

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Shilpa Chawla Jamenis

2011-01-01

Conclusion : These results indicate that the shear bond strength of all the three groups was clinically acceptable with no significant difference between them but more adhesive was left on enamel treated with acid and laser as compared to self-etch primer treated enamel.

Two-year water degradation of self-etching adhesives bonded to bur ground enamel.

Science.gov (United States)

Abdalla, Ali I; Feilzer, Albert J

2009-01-01

To evaluate the effect of water storage on the microshear bond strength to ground enamel of three "all-in-one" self-etch adhesives: Futurabond DC, Clearfil S Tri Bond and Hybrid bond; a self-etching primer; Clearfil SE Bond and an etch-and-rinse adhesive system, Admira Bond. Sixty human molars were used. The root of each tooth was removed and the crown was sectioned into two halves. The convex enamel surfaces were reduced by polishing on silicon paper to prepare a flat surface that was roughened with a parallel-sided diamond bur with abundant water for five seconds. The bonding systems were applied on this surface. Prior to adhesive curing, a hollow cylinder (2.0 mm in height/0.75 mm in internal diameter) was placed on the treated surfaces and cured. A resin composite was then inserted into the tube and cured. For each adhesive, two procedures were carried out: A--the specimens were kept in water for 24 hours, then the tube was removed and the microshear bond strength was determined in a universal testing machine at a crosshead speed of 0.5 mm/minute; B--the specimens were stored in water for two-years before microshear testing. The fractured surface of the bonded specimens after each test procedure was examined by SEM. For the 24-hour control, there was no significant difference in bond strength between the tested adhesives. After two years of water storage, the bond strength of Admira Bond, Clearfil SE Bond and Futurabond DC decreased, but the reduction was not significantly different from that of 24 hours. For Clearfil S Tri Bond and Hybrid Bond, the bond strengths were significantly reduced compared to their 24-hour results.

Adhesion of multimode adhesives to enamel and dentin after one year of water storage.

Science.gov (United States)

Vermelho, Paulo Moreira; Reis, André Figueiredo; Ambrosano, Glaucia Maria Bovi; Giannini, Marcelo

2017-06-01

This study aimed to evaluate the ultramorphological characteristics of tooth-resin interfaces and the bond strength (BS) of multimode adhesive systems to enamel and dentin. Multimode adhesives (Scotchbond Universal (SBU) and All-Bond Universal) were tested in both self-etch and etch-and-rinse modes and compared to control groups (Optibond FL and Clearfil SE Bond (CSB)). Adhesives were applied to human molars and composite blocks were incrementally built up. Teeth were sectioned to obtain specimens for microtensile BS and TEM analysis. Specimens were tested after storage for either 24 h or 1 year. SEM analyses were performed to classify the failure pattern of beam specimens after BS testing. Etching increased the enamel BS of multimode adhesives; however, BS decreased after storage for 1 year. No significant differences in dentin BS were noted between multimode and control in either evaluation period. Storage for 1 year only reduced the dentin BS for SBU in self-etch mode. TEM analysis identified hybridization and interaction zones in dentin and enamel for all adhesives. Silver impregnation was detected on dentin-resin interfaces after storage of specimens for 1 year only with the SBU and CSB. Storage for 1 year reduced enamel BS when adhesives are applied on etched surface; however, BS of multimode adhesives did not differ from those of the control group. In dentin, no significant difference was noted between the multimode and control group adhesives, regardless of etching mode. In general, multimode adhesives showed similar behavior when compared to traditional adhesive techniques. Multimode adhesives are one-step self-etching adhesives that can also be used after enamel/dentin phosphoric acid etching, but each product may work better in specific conditions.

Enamel shear bond strength of two orthodontic self-etching bonding systems compared to Transbond™ XT.

Science.gov (United States)

Hellak, Andreas; Rusdea, Patrick; Schauseil, Michael; Stein, Steffen; Korbmacher-Steiner, Heike Maria

2016-11-01

The aim of this in vitro study was to compare the shear bond strength (SBS) and Adhesive Remnant Index (ARI) scores of two self-etching no-mix adhesives (Prompt L-Pop™ and Scotchbond™) for orthodontic appliances to the commonly used total etch system Transbond XT™ (in combination with phosphoric acid). In all, 60 human premolars were randomly divided into three groups of 20 specimens each. In group 1 (control), brackets were bonded with Transbond™ XT primer. Prompt L-Pop™ (group 2) and Scotchbond™ Universal (group 3) were used in the experimental groups. Lower premolar brackets were bonded by light curing the adhesive. After 24 h of storage, the shear bond strength (SBS) was measured using a Zwicki 1120 testing machine. The adhesive remnant index (ARI) was determined under 10× magnification. The Kruskal-Wallis test was used to statistically compare the SBS and the ARI scores. No significant differences in the SBS between any of the experimental groups were detected (group 1: 15.49 ± 3.28 MPa; group 2: 13.89 ± 4.95 MPa; group 3: 14.35 ± 3.56 MPa; p = 0.489), nor were there any significant differences in the ARI scores (p = 0.368). Using the two self-etching no-mix adhesives (Prompt L-Pop™ and Scotchbond™) for orthodontic appliances does not affect either the SBS or ARI scores in comparison with the commonly used total-etch system Transbond™ XT. In addition, Scotchbond™ Universal supports bonding on all types of surfaces (enamel, metal, composite, and porcelain) with no need for additional primers. It might therefore be helpful for simplifying bonding in orthodontic procedures.

Bond strength with various etching times on young permanent teeth

Energy Technology Data Exchange (ETDEWEB)

Wang, W.N.; Lu, T.C. (School of Dentistry, National Defense Medical Center, Taipei, Taiwan (China))

1991-07-01

Tensile bond strengths of an orthodontic resin cement were compared for 15-, 30-, 60-, 90-, or 120-second etching times, with a 37% phosphoric acid solution on the enamel surfaces of young permanent teeth. Fifty extracted premolars from 9- to 16-year-old children were used for testing. An orthodontic composite resin was used to bond the bracket directly onto the buccal surface of the enamel. The tensile bond strengths were tested with an Instron machine. Bond failure interfaces between bracket bases and teeth surfaces were examined with a scanning electron microscope and calculated with mapping of energy-dispersive x-ray spectrometry. The results of tensile bond strength for 15-, 30-, 60-, or 90-second etching times were not statistically different. For the 120-second etching time, the decrease was significant. Of the bond failures, 43%-49% occurred between bracket and resin interface, 12% to 24% within the resin itself, 32%-40% between resin and tooth interface, and 0% to 4% contained enamel fragments. There was no statistical difference in percentage of bond failure interface distribution between bracket base and resin, resin and enamel, or the enamel detachment. Cohesive failure within the resin itself at the 120-second etching time was less than at other etching times, with a statistical significance. To achieve good retention, to decrease enamel loss, and to reduce moisture contamination in the clinic, as well as to save chairside time, a 15-second etching time is suggested for teenage orthodontic patients.

Bond strengths of brackets bonded to enamel surfaces conditioned with femtosecond and Er:YAG laser systems.

Science.gov (United States)

Aglarci, Cahide; Demir, Necla; Aksakalli, Sertac; Dilber, Erhan; Sozer, Ozlem Akinci; Kilic, Hamdi Sukur

2016-08-01

The aim of this study was to compare femtosecond and Er:YAG laser systems with regard to enamel demineralization and bracket bond strength. Human-extracted premolars were randomized to three groups (n = 17) depending on the conditioning treatment used for the buccal surfaces: 37 % orthophosphoric acid, Er:YAG laser etching (MSP mode 120 mJ, 10 Hz, 1.2 W), and femtosecond laser etching (0.4 W, 800 nm, 90 fs/pulse, 1 kHz). Metal brackets were bonded with Transbond XT to the conditioned surfaces and light cured for 20 s. The samples were thermocycled (5000 cycles, 5-55 °C) and subjected to shear bond strength (SBS) testing using a universal testing machine. Failure types were analyzed under an optical stereomicroscope and SEM. The adhesive remnant index (ARI) was evaluated to assess residual adhesive on the enamel surface. The results revealed no significant differences in SBS between the Er:YAG laser (7.2 ± 3.3 MPa) and acid etching groups (7.3 ± 2.7 MPa; p enamel interface.

Bond strength of etch-and-rinse and self-etch adhesive systems to enamel and dentin irradiated with a novel CO2 9.3 μm short-pulsed laser for dental restorative procedures.

Science.gov (United States)

Rechmann, Peter; Bartolome, N; Kinsel, R; Vaderhobli, R; Rechmann, B M T

2017-12-01

The objective of this study was to evaluate the influence of CO 2 9.3 μm short-pulsed laser irradiation on the shear bond strength of composite resin to enamel and dentin. Two hundred enamel and 210 dentin samples were irradiated with a 9.3 µm carbon dioxide laser (Solea, Convergent Dental, Inc., Natick, MA) with energies which either enhanced caries resistance or were effective for ablation. OptiBond Solo Plus [OptiBondTE] (Kerr Corporation, Orange, CA) and Peak Universal Bond light-cured adhesive [PeakTE] (Ultradent Products, South Jordan, UT) were used. In addition, Scotchbond Universal [ScotchbondSE] (3M ESPE, St. Paul, MN) and Peak SE self-etching primer with Peak Universal Bond light-cured adhesive [PeakSE] (Ultradent Products) were tested. Clearfil APX (Kuraray, New York, NY) was bonded to the samples. After 24 h, a single plane shear bond test was performed. Using the caries preventive setting on enamel resulted in increased shear bond strength for all bonding agents except for self-etch PeakSE. The highest overall bond strength was seen with PeakTE (41.29 ± 6.04 MPa). Etch-and-rinse systems achieved higher bond strength values to ablated enamel than the self-etch systems did. PeakTE showed the highest shear bond strength with 35.22 ± 4.40 MPa. OptiBondTE reached 93.8% of its control value. The self-etch system PeakSE presented significantly lower bond strength. The shear bond strength to dentin ranged between 19.15 ± 3.49 MPa for OptiBondTE and 43.94 ± 6.47 MPa for PeakSE. Etch-and-rinse systems had consistently higher bond strength to CO 2 9.3 µm laser-ablated enamel. Using the maximum recommended energy for dentin ablation, the self-etch system PeakSE reached the highest bond strength (43.9 ± 6.5 MPa).

Microstructural analysis of demineralized primary enamel after in vitro toothbrushing

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Neves Aline de Almeida

2002-01-01

Full Text Available The aim of this study was to investigate, in vitro, the morphological characteristics of demineralized primary enamel subjected to brushing with a dentifrice with or without fluoride. In order to do so, 32 enamel blocks were divided in 4 different groups containing 8 blocks each. They were separately immersed in artificial saliva for 15 days. The experimental groups were: C - control; E - submitted to etching with 37% phosphoric acid gel (30 s; EB - submitted to etching and brushing 3 times a day with a non-fluoridated dentifrice; EBF = submitted to etching and brushing 3 times a day with a fluoridated dentifrice. The toothbrushing force was standardized at 0.2 kgf and 15 double strokes were performed on each block. After the experimental period, the samples were prepared and examined under SEM. The control group (C showed a smooth surface, presenting scratches caused by habitual toothbrushing. The etched samples (E exhibited different degrees of surface disintegration, but the pattern of acid etching was predominantly the type II dissolution. The brushed surfaces were smooth, with elevations which corresponded to the exposure of Tomes? process pits and depressions which corresponded to interrod enamel. Particles resembling calcium carbonate were found in the most protected parts of the grooves. No morphological differences were observed between brushing with fluoridated (EBF and non-fluoridated (EB dentifrice. The results suggest that the mechanical abrasion caused by brushing demineralized enamel with dentifrice smoothes the rough etched surface, and the presence of fluoride does not cause morphological modifications in this pattern.

Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser

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Patrícia T Pires

2013-01-01

Full Text Available Context: Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching. Aims: Evaluate shear bond strength (SBS values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values. Subjects and Methods: One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15 and to enamel morphology analysis ( n = 5 after Er:YAG laser preparation as follows: Group I - 37% phosphoric acid (PA+ ExciTE® ; Group II - ExciTE® ; Group III - AdheSE® self-etching; Group IV - FuturaBond® no-rinse. NR; Group V - Xeno® V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min. Statistical Analysis Used: One-way ANOVA and post-hoc tests (p < 0.05. For the morphology evaluation, specimens were immersed in Ethylenediamine tetraacetic acid (EDTA and the etching pattern analyzed under Scanning Electron Microscope (SEM. Results: Mean bond strengths were Group I - 47.17 ± 1.61 MPa (type I etching pattern; Group II - 32.56 ± 1.64 MPa, Group III - 29.10 ± 1.34 MPa, Group IV - 23.32 ± 1.53 MPa (type III etching pattern; Group V - 24.43 MPa ± 1.55 (type II etching pattern. Conclusions: Different adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE® and ExciTE® without condition with PA. FuturaBond® NR and Xeno® V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.

SEM analysis of enamel surface treated by Er:YAG laser: influence of irradiation distance.

Science.gov (United States)

Souza-Gabriel, A E; Chinelatti, M A; Borsatto, M C; Pécora, J D; Palma-Dibb, R G; Corona, S A M

2008-07-01

Depending on the distance of laser tip to dental surface a specific morphological pattern should be expected. However, there have been limited reports that correlate the Er:YAG irradiation distance with dental morphology. To assess the influence of Er:YAG laser irradiation distance on enamel morphology, by means of scanning electron microscopy (SEM). Sixty human third molars were employed to obtain discs (approximately =1 mm thick) that were randomly assigned to six groups (n=10). Five groups received Er:YAG laser irradiation (80 mJ/2 Hz) for 20 s, according to the irradiation distance: 11, 12, 14, 16, or 17 mm and the control group was treated with 37% phosphoric acid for 15 s. The laser-irradiated discs were bisected. One hemi-disc was separated for superficial analysis without subsequent acid etching, and the other one, received the phosphoric acid for 15 s. Samples were prepared for SEM. Laser irradiation at 11 and 12 mm provided an evident ablation of enamel, with evident fissures and some fused areas. At 14, 16 and 17 mm the superficial topography was flatter than in the other distances. The subsequent acid etching on the lased-surface partially removed the disorganized tissue. Er:YAG laser in defocused mode promoted slight morphological alterations and seems more suitable for enamel conditioning than focused irradiation. The application of phosphoric acid on lased-enamel surface, regardless of the irradiation distance, decreased the superficial irregularities.

Effects of a pulsed Nd:YAG laser on enamel and dentin

Science.gov (United States)

Myers, Terry D.

1990-06-01

Enamel and dentin samples were exposed extraorally to a pulsed neodymium yttriuma1uminumgarnet (Nd:YAG) laser. The lased samples were observed using both scanning electron microscopy and histological techniques to determine the effects of the laser. The present study has provided the following points: (1) Properly treated, enamel can be 1aser etched to a depth comparable to that achieved with phosphoric acid etching; and (2) both carious and noncarious dentin can be vaporized by the Nd:YAG laser. No cracking or chipping of any enamel or dentin sample was observed histologically or under the SEM.

Effect of ethanol-wet-bonding technique on resin–enamel bonds

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Muhammet Kerim Ayar

2014-03-01

Conclusion: The ethanol-wet-bonding technique may increase the bond strength of commercial adhesives to enamel. The chemical composition of the adhesives can affect the bond strength of adhesives when bonding to acid-etched enamel, using the ethanol-wet-bonding technique. Some adhesive systems used in the present study may simultaneously be applied to enamel and dentin using ethanol-wet-bonding. Furthermore, deploying ethanol-wet-bonding for the tested commercial adhesives to enamel can increase the adhesion abilities of these adhesives to enamel.

COMPARATIVE STUDY OF THE SHEAR BOND STRENGTH OF COMPOSITE RESIN TO DENTAL ENAMEL CONDITIONED WITH PHOSPHORIC ACID OR Nd: YAG LASER

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EDUARDO Carlos de Paula

1997-01-01

Full Text Available This study has been focused on a comparison between the shear bond strength of a composite resin attached to dental enamel surface, after a 35% phosphoric acid etching and after a Nd:YAG laser irradiation with 165.8 J/cm2 of energy density per pulse. After etching and attaching resin to these surfaces, the specimens were thermocycled and then underwent the shearing bond strength tests at a speed of 5 mm/min. The results achieved, after statistical analysis with Student's t-test, showed that the adhesion was significantly greater in the 35% phosphoric acid treated group than in the group treated with the Nd:YAG laser, thus demonstrating the need for developing new studies to reach the ideal parameters for an effective enamel surface conditioning as well as specific adhesives and composite resins when Nd:YAG laser is used

Evaluation of human dental loss caused by carbamide peroxide bleacher compared with phosphoric acid conditioning - radioactive method

International Nuclear Information System (INIS)

Adachi, Eduardo Makoto; Yousseff, Michel Nicolau; Saiki, Mitiko

2002-01-01

The radiometric method was applied to the evaluation of dental loss caused by carbamide peroxide when it is applied on the surface layers of enamel and dentin tissues. Also the dental loss caused by the etching with 37% phosphoric acid procedure used in aesthetic restoration was assessed for comparison with those results obtained. The tooth samples irradiated with a P standard in a thermal neutron flux of the nuclear reactor were placed in contact with 10% carbamide peroxide or with 37% phosphoric acid solution. The radioactivity of 32 P transferred from the radioactive teeth to the bleaching gel or to etching acid was measured using a Geiger Muller detector to calculate the mass of P removed in this treatment and losses were calculated after obtaining their P concentrations. Results obtained indicated that enamel and dentin exposed to carbamide peroxide bleaching agent lose phosphorus. The extent of enamel loss was smaller than that obtained for dentin. In the case of acid etching, there was no difference between the results obtained for enamel and dentin loss. Also the dentin loss obtained after a treatment of 30 applications of 10% carbamide peroxide was the same magnitude of that one application of 37% phosphoric acid. (author)

Electrophoretic demonstration of glycoproteins, lipoproteins, and phosphoproteins in human and bovine enamel

DEFF Research Database (Denmark)

Kirkeby, S; Moe, D; Bøg-Hansen, T C

1990-01-01

Enamel proteins from fully mineralized human molars and from bovine tooth germs were separated by electrophoresis. The gels were stained for detection of glycoproteins, lipoproteins, and phosphoproteins. Glycoproteins were shown by periodic acid-Schiff staining and lectin blotting. In mature human...... enamel a number of high molecular weight proteins could be demonstrated after ethylenediaminetetra-acetic acid demineralization and subsequent Triton X-100 extraction. These proteins are suggested to be lipoproteins. Phosphoproteins could only be visualized in enamel matrix from the tooth germs....

Sealing effectiveness of fissure sealant bonded with universal adhesive systems on saliva-contaminated and noncontaminated enamel.

Science.gov (United States)

Memarpour, Mahtab; Shafiei, Fereshteh; Zarean, Mehran; Razmjoei, Faranak

2018-01-01

The effectiveness of sealants is dependent upon their adhesion to enamel surface. The aim of the study was to evaluate the sealing ability of a pit and fissure sealant used with a universal adhesive (etch-and-rinse vs. self-etch modes) when the site is contaminated with saliva. Adhesive properties were evaluated as microleakage and scanning electron microscopic (SEM) characteristics. A total of 72 mandibular third molars were randomly divided into 6 groups (n=12). Occlusal pits and fissures were sealed with an unfilled resin fissure sealant (FS) material with or without saliva contamination. The groups included: 1) phosphoric acid etching + FS (control), 2) phosphoric acid etching + Scotchbond Universal (etch-and-rinse) + FS, 3) phosphoric acid etching + saliva + Scotchbond Universal (etch-and-rinse) + FS, 4) Scotchbond Universal (self-etching) + FS,5) Scotchbond Universal (self-etching) + saliva + FS, and 6) Scotchbond Universal (self-etching) + saliva + Scotchbond Universal + FS. After thermocycling, the teeth were placed in 0.5% fuchsin, sectioned, and evaluated by digital microscopy. Two samples from each group were also observed by SEM. The data were analyzed with Kruskal-Wallis and Mann-Whitney tests for a significance of p universal adhesive in etch-and-rinse or self-etch modes was similar to that of conventional acid etching. Saliva contamination had a negative effect on sealant adhesion to pretreated enamel. Key words: Pit and fissure sealant, Universal adhesive, Saliva.

Effect of bromelain and papain gel on enamel deproteinisation before orthodontic bracket bonding.

Science.gov (United States)

Pithon, Matheus Melo; Campos, Matheus Souza; Coqueiro, Raildo da Silva

2016-05-01

To test the hypothesis that enamel surface deproteinisation with different concentrations of bromelain in association with 10% papain increases the shear bond strength (SBS) of brackets bonded with orthodontic composite and resin modified glass ionomer cement (RMGIC). Orthodontic brackets were attached according to the following protocols to 195 bovine incisors, which were acquired and divided into 13 groups: 1) Transbond XT (TXT) according to the manufacturer's recommendations; 2) Deproteinisation with 3% bromelain (BD) plus 10% papain and TXT; 3) 6% BD plus 10% Papain and TXT; 4) RMGIC, without enamel deproteinisation and without acid etching; 5) RMGIC, with 3% BD plus 10% papain and without acid etching; 6) RMGIC, with 6% BD plus 10% papain and without acid etching; 7) attachment using RMGIC following etching with polyacrylic acid; 8) 3% BD plus 10% papain, attachment using RMGIC and etching with polyacrylic acid; 9) 6% BD plus 10% papain, and attachment using RMGIC following etching with polyacrylic acid; 10) etching with 37% phosphoric acid and attachment using RMGIC; 11) 3% BD plus 10% papain, etching with 37% phosphoric acid and attachment using RMGIC; 12) 6% BD plus 10% papain, etching with 37% phosphoric acid and attachment using RMGIC; 13) deproteinisation with 2.5% sodium hypochlorite (NaOCl), etching with polyacrylic acid and RMGIC. After bonding, the brackets were removed by a universal mechanical testing machine, which recorded shear bond strength at failure. The material remaining on the tooth was assessed using the adhesive remnant index (ARI). Deproteinisation with 3% and 6% bromelain gel plus papain significantly increased the shear bond strength (p < 0.05), when acid etching was performed with phosphoric acid, followed by primer application and attachment using Transbond XT (Group 3) and when attached with RMGIC without etching. Deproteinisation with 6% bromelain gel plus papain significantly increased (p < 0.05) the ARI score only when

In vitro effect of energy drinks on human enamel surface

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Marise Sano Suga MATUMOTO

Full Text Available Abstract Introduction Energy drinks (ED possess low pH and citric acid in their composition, making them potentially erosive beverages that can contribute to the high dental erosion rates found currently in the general population and also in young people. Objective To evaluate the mean pH and titratable acidity of commercial ED and the influence of a brand of ED on the superficial microhardness of human enamel. Material and method Ten commercial ED were selected and the pH of two lots of each ED with and without gas was obtained. Acid titration was conducted with the addition of NaOH aliquots until the pH 7 was reached. Eighteen human enamel specimens were allocated in three groups (N=6, Red Bull (RB, Red Bull Light (RBL and distilled water (C, submitted to an acid challenge with the ED, six consecutive times, with 12 hours intervals, during three days. Knoop microhardness was measured before and after the acid challenge. Result All ED brands tested presented low pH levels ranging from 2.1 to 3.2. Regarding titratable acidity, it was found that the amount of base required promoting the neutralization of the solutions ranged from 1200μL to 3750μL. Samples of human enamel in the RB and RBL groups submitted to the acid challenge presented significantly decreased Knoop microhardness when compared with the group C. Conclusion All ED examined have potential to promote mineral loss due to the low pH and high titratable acidity. The ED analyzed promoted significant mineral losses on the dental enamel surface.

Shear bond strength and SEM morphology evaluation of different dental adhesives to enamel prepared with ER:YAG laser.

Science.gov (United States)

Pires, Patrícia T; Ferreira, João C; Oliveira, Sofia A; Azevedo, Alvaro F; Dias, Walter R; Melo, Paulo R

2013-01-01

Early observations of enamel surfaces prepared by erbium lasers motivated clinicians to use laser as an alternative to chemical etching. Evaluate shear bond strength (SBS) values of different dental adhesives on Erbium:Yttrium Aluminum Garnet (Er:YAG) laser prepared enamel and to evaluate possible etching patterns correlations between dental adhesives and SBS values. One hundred bovine incisors were randomly assigned to SBS tests on enamel (n = 15) and to enamel morphology analysis (n = 5) after Er:YAG laser preparation as follows: Group I - 37% phosphoric acid (PA)+ ExciTE(®); Group II - ExciTE(®); Group III - AdheSE(®) self-etching; Group IV - FuturaBond(®) no-rinse. NR; Group V - Xeno(®) V. Teeth were treated with the adhesive systems and subjected to thermal cycling. SBS were performed in a universal testing machine at 5 mm/min. One-way ANOVA and post-hoc tests (P adhesive systems yielded significantly different SBSs. Acid etching significantly increased the adhesion in laser treated enamel. No differences in SBS values were obtained between AdheSE(®) and ExciTE(®) without condition with PA. FuturaBond(®) NR and Xeno(®) V showed similar SBS, which was lower in comparison to the others adhesives. No correlation between enamel surface morphology and SBS values was observed, except when PA was used.

Microtensile bond strength of eleven contemporary adhesives to enamel.

Science.gov (United States)

Inoue, Satoshi; Vargas, Marcos A; Abe, Yasuhiko; Yoshida, Yasuhiro; Lambrechts, Paul; Vanherle, Guido; Sano, Hidehiko; Van Meerbeek, Bart

2003-10-01

To compare the microtensile bond strength (microTBS) to enamel of 10 contemporary adhesives, including three one-step self-etch systems, four two-step self-etch systems and three two-step total-etch systems, with that of a conventional three-step total-etch adhesive. Resin composite (Z100, 3M) was bonded to flat, #600-grit wet-sanded enamel surfaces of 18 extracted human third molars using the adhesives strictly according to the respective manufacturer's instructions. After storage overnight in 37 degrees C water, the bonded specimens were sectioned into 2-4 thin slabs of approximately 1 mm thickness and 2.5 mm width. They were then trimmed into an hourglass shape with an interface area of approximately 1 mm2, and subsequently subjected to microTBS-testing with a cross-head speed of 1 mm/minute. The microTBS to enamel varied from 3.2 MPa for the experimental one-step self-etch adhesive PQ/Universal (self-etch) to 43.9 MPa for the two-step total-etch adhesive Scotchbond 1. When compared with the conventional three-step total-etch adhesive OptiBond FL, the bond strengths of most adhesives with simplified application procedures were not significantly different, except for two one-step self-etch adhesives, experimental PQ/Universal (self-etch) and One-up Bond F, that showed lower bond strengths. Specimen failures during sample preparation were recorded for the latter adhesives as well.

Effect of gallic acid on the wear behavior of early carious enamel

International Nuclear Information System (INIS)

Gao, S S; Huang, S B; Yu, H Y; Qian, L M

2009-01-01

The purpose of this research was to investigate the wear behavior of early carious enamel remineralized with gallic acid. Forty natural human premolar specimens with early caries lesions were prepared. A remineralization pH-cycling treatment agent of 4000 ppm gallic acid was used for 12 days to treat the early lesions. The changes in microhardness were monitored. Nanoscratch tests were used to evaluate wear resistance. The experimental data were analyzed by using a t-test. The widths of traces were measured by an AMBIOS XP-2 stylus profilometer. After remineralization, all samples re-hardened significantly. The coefficients of friction became higher, and the widths of scratches were larger than they were before remineralization. Gallic acid significantly improved the early carious enamel's hardness. The wear damage of the samples treated with gallic acid was more severe than that of the control group. There were more obvious cracks and delaminations on the traces of the treated group. Compared with the control group, the enamel remineralized with gallic acid had inferior wear resistance. After remineralization, the dominant damage mechanisms of early carious enamel had changed from plastic deformation and adhesive wear to a combination of brittle cracks and delamination of enamel.

The effects of NaF, Fluor-protector and Aminofluoride on the enamel of permanent teeth in children

OpenAIRE

Beloica, Dragan

1984-01-01

The effects of three fluor preparation (NaF, Fluor-Protector and Aminofluoride) on the enamel of permanent teeth has been studied by determinig the fluor concentrations in the enamel surface layer and the resistance of enamel to the effects of acids. The fluor preparations were applied to intact extracted teeth. Fluor concentrations were determined in the enamel samples using a Bedkman electrode with pH meter for fliuorides. Acid resistance was established by etching the enamnel samples, prev...

Effects of potassium oxalate on knoop hardness of etch-and-rinse adhesives.

Science.gov (United States)

Silva, S M A; Malacarne-Zanon, J; Carvalho, R M; Alves, M C; De Goes, M F; Anido-Anido, A; Carrilho, M R

2012-01-01

The objective of this study was to determine whether the hardness of etch-and-rinse adhesives may be affected by the pretreatment of acid-etched dentin with potassium oxalate desensitizer. Unerupted human third molars were cut into crown segments by removing the occlusal enamel and roots. The pulp chamber of these crown segments was connected to a syringe barrel filled with phosphate-buffered saline so that the moisture of dentin was maintained during the bonding procedures. Three etch-and-rinse adhesives-two two-step systems (Adper Single Bond 2 [SB], One-Step [OS]) and one three-step system (Adper Scotchbond Multi-Purpose [MP])-were applied to acid-etched dentin that had been treated (experimental groups) or not (control groups) with potassium oxalate (BisBlock). The Knoop hardness (KHN) of adhesives was taken at different sites of the outer surface of the adhesive-bonded dentin. The KHN of the three tested adhesives applied to acid-etched dentin treated with potassium oxalate was significantly lower than that exhibited by the respective controls (not treated with oxalate; padhesive, the treatment with potassium oxalate reduced the adhesives' KHN (psystem exhibiting the lowest KHN compared with the MP and SB systems.

Composite shear bond strength to dry and wet enamel with three self-etch adhesives

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Shafiee F

2006-01-01

Full Text Available Background and Aim: The bonding mechanisms of self etching primers, based upon the simultaneous etching and priming of dentin, simplifies the bonding technique, but the efficiency of these systems is still controversial. This study compared the shear bond strength of three self etch adhesive systems in dry and wet conditions. Materials and Method: In this experimental study, 77 intact bovine lower incisors with flat 600 grit sanded enamel surface were fixed in acrylic molds and divided into 7 groups, of 11 teeth. The enamel surfaces were treated according to a special procedure as follows: Group 1: Prompt L-Pop (PLP in dry condition, Group 2: Prompt L-Pop in wet condition, Group 3: Clearfield SE Bond (CSEB in dry condition, Group 4: Clearfield SE Bond in wet condition, Group 5: iBond (iB in dry condition, Group 6: iBond in wet condition, Group 7: Margin Bond (Control in dry condition. Surfaces were air dried for ten seconds, or blot dried in wet condition. Composite resin was bonded on the enamel and built up by applying a cylindric teflon split mold (4 mm height 2mm diameter. After 24 hours storage in dionized water at room temperature, all specimens were thermocycled and shear bond test was employed by a universal testing machine (Instron with a cross-head speed of 1mm/min. The shear bond strength was recorded in MPa and data were analyzed with ANOVA and Scheffe statistical tests. P<0.05 was considered as statistically significant. The mode of failure was examined under a stereomicroscope. Results: 1- Shear bond strength of CSEB in dry condition (21.5 ± 4.8 MPa was significantly higher than PLP and iB groups (p<0.0001. 2- Shear bond strength of iB and PLP groups in dry condition (9.60 ± 2.2, 9.49 ± 3 MPa were significantly lower than CSEB and control (2.99 ± 5.1 MPa (P<0.0001. 3- There was no significant difference between PLP and iB groups in dry condition (P=1. 4- Shear bond strength of CSEB in wet condition (21.8 ± 3 MPa was

Effect of gallic acid on the wear behavior of early carious enamel

Energy Technology Data Exchange (ETDEWEB)

Gao, S S; Huang, S B; Yu, H Y [State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041 (China); Qian, L M, E-mail: yhyang6812@scu.edu.c [Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)

2009-06-15

The purpose of this research was to investigate the wear behavior of early carious enamel remineralized with gallic acid. Forty natural human premolar specimens with early caries lesions were prepared. A remineralization pH-cycling treatment agent of 4000 ppm gallic acid was used for 12 days to treat the early lesions. The changes in microhardness were monitored. Nanoscratch tests were used to evaluate wear resistance. The experimental data were analyzed by using a t-test. The widths of traces were measured by an AMBIOS XP-2 stylus profilometer. After remineralization, all samples re-hardened significantly. The coefficients of friction became higher, and the widths of scratches were larger than they were before remineralization. Gallic acid significantly improved the early carious enamel's hardness. The wear damage of the samples treated with gallic acid was more severe than that of the control group. There were more obvious cracks and delaminations on the traces of the treated group. Compared with the control group, the enamel remineralized with gallic acid had inferior wear resistance. After remineralization, the dominant damage mechanisms of early carious enamel had changed from plastic deformation and adhesive wear to a combination of brittle cracks and delamination of enamel.

Wear of human enamel: a quantitative in vitro assessment.

Science.gov (United States)

Kaidonis, J A; Richards, L C; Townsend, G C; Tansley, G D

1998-12-01

Many factors influence the extent and rate at which enamel wears. Clinical studies in humans are limited by difficulties in the accurate quantification of intra-oral wear and by a lack of control over the oral environment. The purpose of this study was to determine the wear characteristics of human dental enamel under controlled experimental conditions. An electro-mechanical tooth wear machine, in which opposing enamel surfaces of sectioned, extracted teeth were worn under various conditions, was used to simulate tooth grinding or bruxism. Enamel surface wear was quantified by weight to an accuracy of 0.1 mg, with water uptake and loss controlled. The variables considered included the structure and hardness of enamel, facet area, duration of tooth contact, relative speed of opposing surfaces, temperature, load, pH, and the nature of the lubricant. Enamel wear under non-lubricated conditions increased with increasing load over the range of 1.7 to 16.2 kg. The addition of a liquid lubricant (pH = 7) reduced enamel wear up to 6.7 kg, but when the load increased above this threshold, the rate of wear increased dramatically. With the viscosity of the lubricant constant and pH = 3, the rate of wear was further reduced to less than 10% of the non-lubricated rate at 9.95 kg, after which the rate again increased substantially. Under more extreme conditions (pH = 1.2, simulating gastric acids), the wear was excessive under all experimental loads. When saliva was used as a lubricant, the amount of wear was relatively low at 9.95 kg, but rapid wear occurred at 14.2 kg and above. These results indicate that under non-lubricated conditions, enamel wear remains low at high loads due to the dry-lubricating capabilities of fine enamel powder. Under lubricated conditions, low loads with an acidic lubricant lead to little enamel wear, whereas very low pH results in a high rate of wear under all loads.

An In Vitro Evaluation of Leakage of Two Etch and Rinse and Two Self-Etch Adhesives after Thermocycling

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Geerts, Sabine; Bolette, Amandine; Seidel, Laurence; Guéders, Audrey

2012-01-01

Our experiment evaluated the microleakage in resin composite restorations bonded to dental tissues with different adhesive systems. 40 class V cavities were prepared on the facial and lingual surfaces of each tooth with coronal margins in enamel and apical margins in cementum (root dentin). The teeth were restored with Z100 resin composite bonded with different adhesive systems: Scotchbond Multipurpose (SBMP), a 3-step Etch and Rinse adhesive, Adper Scotchbond 1 XT (SB1), a 2-step Etch and Rinse adhesive, AdheSE One (ADSE-1), a 1-step Self-Etch adhesive, and AdheSE (ADSE), a 2-step Self-Etch adhesive. Teeth were thermocycled and immersed in 50% silver nitrate solution. When both interfaces were considered, SBMP has exhibited significantly less microleakage than other adhesive systems (resp., for SB1, ADSE-1 and ADSE, P = 0.0007, P adhesives, microleakage was found greater at enamel than at dentin interfaces (for ADSE, P = 0.024 and for ADSE-1, P adhesive systems, there was no significant difference between enamel and dentin interfaces; (3) SBMP was found significantly better than other adhesives both at enamel and dentin interfaces. In our experiment Etch and Rinse adhesives remain better than Self-Etch adhesives at enamel interface. In addition, there was no statistical difference between 1-step (ADSE-1) and 2-step (ADSE) Self-Etch adhesives. PMID:22675358

The shear bond strength of self-adhesive resin cements to dentin and enamel: an in vitro study.

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Rodrigues, Raphaela F; Ramos, Carla M; Francisconi, Paulo A S; Borges, Ana Flávia S

2015-03-01

Clinicians continue to search for ways to simplify bonding procedures without compromising clinical efficacy. The purpose of this study was to evaluate the shear strength of self-adhesive cements RelyX U100 and RelyX U200, and conventional resin cement RelyX ARC to enamel and dentin after different surface treatments. The crowns of 120 bovine incisor teeth were separated from the roots and embedded in epoxy resin in polyvinyl chloride tubes. In each tooth, the area to be cemented was delimited with central holed adhesive tape. The teeth were distributed into 12 groups (n=10) according to the substrate; etched or not with 37% phosphoric acid; and cement type of enamel-U100, enamel-phosphoric acid-U100, enamel-U200, enamel-phosphoric acid-U200, enamel-ARC, enamel-phosphoric acid-ARC, dentin-U100, dentin-phosphoric acid-U100, dentin-U200, dentin-phosphoric acid-U200, dentin-ARC, and dentin-phosphoric acid-ARC. After 7 days of storage in artificial saliva, shear strength tests were performed by using a universal testing machine (0.5 mm/min). The data were analyzed with 3-way ANOVA and the Tukey test (α=.05). Fracture analysis was performed with a light microscope. Two specimens from each group were analyzed with a scanning electron microscope. In enamel, ARC (9.96 MPa) had higher shear strength (P=.038) than U100 (5.14 MPa); however, after surface etching, U100 (17.81 MPa) and U200 (17.52 MPa) had higher shear strength (Padhesive type. U200 self-adhesive cement had similar bond strength to the ARC in enamel, but the combination with phosphoric acid had the best bond strength. For dentin, self-adhesive resin cements are equally effective alternatives to conventional resin cement. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Effect of etching on bonding of a self-etch adhesive to dentine affected by amelogenesis imperfecta.

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Epasinghe, Don Jeevanie; Yiu, Cynthia Kar Yung

2018-02-01

Dentine affected by amelogenesis imperfecta (AI) is histologically altered due to loss of hypoplastic enamel and becomes hypermineralized. In the present study, we examined the effect of additional acid etching on microtensile bond strength of a self-etch adhesive to AI-affected dentine. Flat coronal dentine obtained from extracted AI-affected and non-carious permanent molars were allocated to two groups: (a) Clearfil SE Bond (control); and (b) Clearfil SE Bond and additional etching with 34% phosphoric acid for 15 seconds. The bonded teeth were sectioned into .8-mm 2 beams for microtensile bond strength testing, and stressed to failure under tension. The bond strength data were analyzed using two-way analysis of variance (dentine type and etching step) and Student-Newman-Keuls multiple comparison test (P<.05). Representative fractured beams from each group were examined under scanning electron microscopy. Both factors, dentine substrate (P<.001) and etching step (P<.05), and their interactions (P<.001), were statistically significant. Additional etching had an adverse effect on the bond strength of Clearfil SE Bond to normal dentine (P<.005), and no significant improvement was found for AI-affected dentine (P=.479). Additional acid etching does not improve the bond strength of a self-etch adhesive to AI-affected dentine. © 2017 John Wiley & Sons Australia, Ltd.

Deformation behavior of human enamel and dentin-enamel junction under compression.

Science.gov (United States)

Zaytsev, Dmitry; Panfilov, Peter

2014-01-01

Deformation behavior under uniaxial compression of human enamel and dentin-enamel junction (DEJ) is considered in comparison with human dentin. This deformation scheme allows estimating the total response from all levels of the hierarchical composite material in contrast with the indentation, which are limited by the mesoscopic and microscopic scales. It was shown for the first time that dental enamel is the strength (up to 1850MPa) hard tissue, which is able to consider some elastic (up to 8%) and plastic (up to 5%) deformation under compression. In so doing, it is almost undeformable substance under the creep condition. Mechanical properties of human enamel depend on the geometry of sample. Human dentin exhibits the similar deformation behavior under compression, but the values of its elasticity (up to 40%) and plasticity (up to 18%) are much more, while its strength (up to 800MPa) is less in two times. Despite the difference in mechanical properties, human enamel is able to suppress the cracking alike dentin. Deformation behavior under the compression of the samples contained DEJ as the same to dentin. This feature allows a tooth to be elastic-plastic (as dentin) and wear resistible (as enamel), simultaneously. © 2013 Elsevier B.V. All rights reserved.

Bond strengths of different orthodontic adhesives after enamel conditioning with the same self-etching primer.

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Scougall-Vilchis, Rogelio J; Zárate-Díaz, Chrisel; Kusakabe, Shusuke; Yamamoto, Kohji

2010-05-01

To determine the shear bond strengths (SBS) of stainless steel brackets bonded with seven light-cured orthodontic adhesives after the enamel was conditioned with the same self-etching primer. A total of 140 extracted human molars were randomly divided into seven groups (N = 20). In all the groups, the enamel was conditioned with Transbond Plus SEP (TPSEP). Stainless steel brackets were bonded with the following orthodontic adhesives: Group I, Transbond XT; Group II, Blūgloo; Group III, BeautyOrtho Bond; Group IV, Enlight; Group V, Light Bond; Group VI, Transbond CC; Group VII, Xeno Ortho. The teeth were stored in distilled water at 37 degrees C for 24 hours and debonded with a universal testing machine. The modified adhesive remnant index (ARI) was also recorded. There were no significant differences in the SBS values among the groups: I (18.0 +/- 7.4 MPa); II (18.3 +/- 5.1 MPa); III (14.8 +/- 4.3 MPa); IV (18.3 +/- 7.0 MPa); V (16.4 +/- 4.3 MPa); VI (20.3 +/- 5.3 MPa); VII (15.9 +/- 6.4 MPa), but significant differences in ARI were found. The seven orthodontic adhesives evaluated in this study can be successfully used for bonding stainless steel brackets when the enamel is conditioned with TPSEP, however, the differences among some groups might influence the clinical bond strengths. In addition, the amount of residual adhesive remaining on the teeth after debonding differed among the adhesives. Further studies are required to better understand the differences in SBS and ARI.

Comparison of shear bond strength between unfilled resin to dry enamel and dentin bonding to moist and dry enamel

Directory of Open Access Journals (Sweden)

Yasini E.

2005-05-01

Full Text Available Statement of Problem: The use of dentine bondings on enamel and dentin in total etch protocols has recently become popular. Unfilled resin is hydrophobic and dentin bonding is hydrophilic in nature. This chemical difference could be effective in enamel bonding process. Purpose: The aim of this study was to compare the shear bond strength of unfilled resin to dry enamel and dentin bonding to dry and moist enamel. Materials and Methods: In this experimental study, a total of 30 incisor teeth were used. The specimens were randomly assigned to three groups of 10. 37% phosphoric acid etchant was applied to the enamel surfaces in each group for 15 seconds, rinsed with water for 20 seconds and dried for 20 seconds with compressed air in groups one and two. After conditioning, group 1 received unfilled resin (Margin Bond, Colten and group 2 received dentin bonding (Single Bond, 3M and in group 3 after conditioning and rinsing with water, a layer of dentin bonding (Single Bond was applied on wet enamel. The enamel and dentin bonding were light cured for 20 seconds. A ring mold 3.5 mm in diameter and 2 mm height was placed over the specimens to receive the composite filling material (Z100, 3M. The composite was cured for 40 seconds. The specimens were thermocycled and shear bond strengths were determined using an Instron Universal Testing Machine. The findings were analyzed by ANOVA One-Way and Tukey HSD tests. Results: Shear bond strength of dentin bonding to dry enamel was significantly less than unfilled resin to dry enamel (P<0.05. There was no significant difference between the bond strength of dentin bonding to moist and dry enamel. In addition bond strength of dentin bonding to wet enamel was not significantly different from unfilled resin to dry enamel. Conclusion: Based on the findings of this study, it is suggested that enamel surface should remain slightly moist after etching before bonding with single bond but when using unfilled resin, the

Effect of a New Surface Treatment Solution on the Bond Strength of Composite to Enamel

Science.gov (United States)

2016-06-01

Bond Strength of Composite to Enamel " is appropriately acknowledged and, beyond brief excerpts, is with the permission of the copyright owner...Solution on the Bond Strength of Composite to Enamel ABSTRACT Clean & Boost (Apex Dental Materials) is a novel surface treatment solution...designed to be used in place of phosphoric acid to increase the bond strength of self-etch adhesives to enamel and more effectively remove contaminants

Bond strength of compomers to dentin using acidic primers.

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Tate, W H; You, C; Powers, J M

1999-10-01

To determine the in vitro bond strengths of seven compomer/bonding agent restorative systems to human dentin. Seven compomer/bonding agents were bonded to human dentin, stored in water at 37 degrees C for 24 hours, and debonded in tension. Bonding conditions were with and without phosphoric acid etching, with and without the use of combined primer/bonding agents, and under moist and wet bond interfaces. Without phosphoric acid etching, F2000/F2000 Compomer Primer/Adhesive and F2000/Single Bond Dental Adhesive System were less sensitive to dentin wetness. With moist dentin, bond strengths of Dyract/Prime & Bond 2.1, Dyract AP/Prime & Bond 2.1, Hytac/OSB light-curing, one-component bonding agent, F2000/Single Bond, and Freedom/STAE single component light-cured dentin/enamel adhesive system, were improved with phosphoric acid etching. Also, with moist dentin, the bond strength of F2000/F2000 Compomer Primer/Adhesive in the 3M Clicker dispensing system was higher without phosphoric acid etching, whereas bonds of Compoglass/Syntac Single-component were not affected by phosphoric acid etching. Bonding did not occur without primer/bonding agent, regardless of surface condition or use of phosphoric acid etching.

Effect of Water Storage on the Micro-shear Bond Strength of Two Self-etch Adhesives to Enamel and Dentin

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Z. Jaberi Ansari

2007-06-01

Full Text Available Objective: This study evaluated the influence of storage time on micro-shear bond strength of two self-etching materials to enamel and dentin.Materials and Methods: Human third molar teeth were sectioned to 1.5 mm thick beams and randomly divided into 2 groups. In group I, SE Bond and in group II, Tri-S Bond was used to bond a composite rod (AP-X to each treated surface. Specimens were prepared according to manufacturer instructions. Each group was further divided into three subgroups according to water storage time; 1 day, 6 and 12 months. Microshear bond strengths were determined under a crosshead speed of 1mm/min using a universal testing machine and expressed in MPa. Data was statistically analyzed by ANOVA and Dunnett post hoc test.Results: Micro-shear bond strength of two adhesives to enamel and dentin showed a slight but not significant decrease over time (P>0.5. After one day, the mean bond strength of enamel in groups I and II were 39.47 and 34.65 MPa and in dentin were 45.20 and 36.0 MPa respectively. There was no statistically significant differencebetween two materials (P=0.190, P=0.082. After six months the bond strength in group I and II was 35.93 and 35.18 MPa for enamel, and 38.27and 35.19 MPa for dentin respectively, these differences was not statistically significant (P=0.520, P=0.179.After one year, the bond strength of enamel in groups I and II, were 34.47and 29.91MPa, and in dentin were 33.86 and 32.53 MPa respectively which was not statistically significant (P=0.609, P=0.991.Conclusion: The micro-shear bond strength of both adhesives to enamel and dentin decreased slightly over time; however these decreases were not statistically significant.

In vitro study of the diode laser effect on artificial demineralized surface of human dental enamel

International Nuclear Information System (INIS)

Ebel, Patricia

2003-01-01

In scientific literature there are many reports about fusion and resolidification of dental enamel after laser irradiation and their capability to generate surfaces with increased resistance to demineralization compared to non-irradiated areas. The use of high power diode laser on demineralized surfaces of human dental enamel is presented as a good alternative in caries prevention. The purpose of this study is to investigate the morphological changes produced by the use of one high power diode laser on human dental enamel surface after demineralization treatment with lactic acid, under chosen parameters. Fifteen samples of human dental molars were used and divided in four groups: control - demineralization treatment with lactic acid and no irradiation, and demineralization treatment with lactic acid followed of irradiation with 212,20 mJ/cm 2 , 282,84 mJ/cm 2 and 325,38 mJ/cm 2 , respectively. The samples were irradiated with high power diode laser (808 nm) with a 300 μm diameter fiber optics. Black ink was used on enamel surface to enhance the superficial absorption. The samples were studied by optical microscopy and scanning electron microscopy. Modifications on the enamel surfaces were observed. Such modifications were characterized by melted and re-solidified region of the enamel. According with our results the best parameter was 2.0 W, presenting the most uniform surface. The use of high power diode laser as demonstrated in this study is able to promote melting and re-solidification on human dental enamel. (author)

Effects of various debonding and adhesive clearance methods on enamel surface: an in vitro study

OpenAIRE

Fan, Xiao-Chuan; Chen, Li; Huang, Xiao-Feng

2017-01-01

Background The purpose of this study was to evaluate orthodontic debonding methods by comparing the surface roughness and enamel morphology of teeth after applying two different debonding methods and three different polishing techniques. Methods Forty eight human maxillary premolars, extracted for orthodontic reasons, were randomly divided into three groups. Brackets were bonded to teeth with RMGIC (Fuji Ortho LC, GC, Tokyo, Japan) (two groups, n?=?18 each) after acid etching (30s), light cur...

A comparative study of shear bond strength of orthodontic bracket after acid-etched and Er:YAG treatment on enamel surface

Science.gov (United States)

Leão, Juliana C.; Mota, Cláudia C. B. O.; Cassimiro-silva, Patricia F.; Gomes, Anderson S. L.

2016-02-01

This study aimed to evaluate the shear bond strength (SBS) of teeth prepared for orthodontic bracket bonding with 37% phosphoric acid and Er:YAG laser. Forty bovine incisors were divided into two groups. In Group I, the teeth were conditioned with 37% phosphoric acid and brackets were bonded with Transbond XT; in Group II, the teeth were irradiated with Er:YAG and bonding with Transbond XT. After SBS test, the adhesive remnant index was determined. Adhesion to dental hard tissues after Er:YAG laser etching was inferior to that obtained after acid etching but exceeded what is believed to be clinically sufficient strength, and therefore can be used in patients.

Analysis of enamel microbiopsies in shed primary teeth by Scanning Electron Microscopy (SEM) and Polarizing Microscopy (PM)

International Nuclear Information System (INIS)

Costa de Almeida, Glauce Regina; Molina, Gabriela Ferian; Meschiari, Cesar Arruda; Barbosa de Sousa, Frederico; Gerlach, Raquel Fernanda

2009-01-01

The aims of this study were 1) to verify how close to the theoretically presumed areas are the areas of enamel microbiopsies carried out in vivo or in exfoliated teeth; 2) to test whether the etching solution penetrates beyond the tape borders; 3) to test whether the etching solution demineralizes the enamel in depth. 24 shed upper primary central incisors were randomly divided into two groups: the Rehydrated Teeth Group and the Dry Teeth Group. An enamel microbiopsy was performed, and the enamel microbiopsies were then analyzed by Scanning Electron Microscopy (SEM) and Polarizing Microscopy (PM). Quantitative birefringence measurements were performed. The 'true' etched area was determined by measuring the etched enamel using the NIH Image analysis program. Enamel birefringence was compared using the paired t test. There was a statistically significant difference when the etched areas in the Rehydrated teeth were compared with those of the Dry teeth (p = 0.04). The etched areas varied from - 11.6% to 73.5% of the presumed area in the Rehydrated teeth, and from 6.6% to 61.3% in the Dry teeth. The mean percentage of variation in each group could be used as a correction factor for the etched area. Analysis of PM pictures shows no evidence of in-depth enamel demineralization by the etching solution. No statistically significant differences in enamel birefringence were observed between values underneath and outside the microbiopsy area in the same tooth, showing that no mineral loss occurred below the enamel superficial layer. Our data showed no evidence of in-depth enamel demineralization by the etching solution used in the enamel microbiopsy proposed for primary enamel. This study also showed a variation in the measured diameter of the enamel microbiopsy in nineteen teeth out of twenty four, indicating that in most cases the etching solution penetrated beyond the tape borders.

Shear bond strength of orthodontic brackets bonded with different self-etching adhesives.

Science.gov (United States)

Scougall Vilchis, Rogelio José; Yamamoto, Seigo; Kitai, Noriyuki; Yamamoto, Kohji

2009-09-01

The purpose of this study was to compare the shear bond strength (SBS) of orthodontic brackets bonded with 4 self-etching adhesives. A total of 175 extracted premolars were randomly divided into 5 groups (n = 35). Group I was the control, in which the enamel was etched with 37% phosphoric acid, and stainless steel brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif). In the remaining 4 groups, the enamel was conditioned with the following self-etching primers and adhesives: group II, Transbond Plus and Transbond XT (3M Unitek); group III, Clearfil Mega Bond FA and Kurasper F (Kuraray Medical, Tokyo, Japan); group IV, Primers A and B, and BeautyOrtho Bond (Shofu, Kyoto, Japan); and group V, AdheSE and Heliosit Orthodontic (Ivoclar Vivadent AG, Liechtenstein). The teeth were stored in distilled water at 37 degrees C for 24 hours and debonded with a universal testing machine. The adhesive remnant index (ARI) including enamel fracture score was also evaluated. Additionally, the conditioned enamel surfaces were observed under a scanning electron microscope. The SBS values of groups I (19.0 +/- 6.7 MPa) and II (16.6 +/- 7.3 MPa) were significantly higher than those of groups III (11.0 +/- 3.9 MPa), IV (10.1 +/- 3.7 MPa), and V (11.8 +/- 3.5 MPa). Fluoride-releasing adhesives (Kurasper F and BeautyOrtho Bond) showed clinically acceptable SBS values. Significant differences were found in the ARI and enamel fracture scores between groups I and II. The 4 self-etching adhesives yielded SBS values higher than the bond strength (5.9 to 7.8 MPa) suggested for routine clinical treatment, indicating that orthodontic brackets can be successfully bonded with any of these self-etching adhesives.

Evaluation of shear bond strength with different enamel pretreatments: An in vitro study

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Anila Charles

2014-01-01

Conclusions: The current findings indicate that enamel surface preparation using bur abrasion results in a significant higher than air abrasion; within the limitations of this study recommend bur abrasion as a viable alternative to acid etching.

Enamel Thickness before and after Orthodontic Treatment Analysed in Optical Coherence Tomography

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Koprowski, Robert; Safranow, Krzysztof; Woźniak, Krzysztof

2017-01-01

Despite the continuous development of materials and techniques of adhesive bonding, the basic procedure remains relatively constant. The technique is based on three components: etching substance, adhesive system, and composite material. The use of etchants during bonding orthodontic brackets carries the risk of damage to the enamel. Therefore, the article examines the effect of the manner of enamel etching on its thickness before and after orthodontic treatment. The study was carried out in vitro on a group of 80 teeth. It was divided into two subgroups of 40 teeth each. The procedure of enamel etching was performed under laboratory conditions. In the first subgroup, the classic method of enamel etching and the fifth-generation bonding system were used. In the second subgroup, the seventh-generation (self-etching) bonding system was used. In both groups, metal orthodontic brackets were fixed and the enamel was cleaned with a cutter fixed on the micromotor after their removal. Before and after the treatment, two-dimensional optical coherence tomography scans were performed. The enamel thickness was assessed on the two-dimensional scans. The average enamel thickness in both subgroups was not statistically significant. PMID:28243604

Enamel Thickness before and after Orthodontic Treatment Analysed in Optical Coherence Tomography

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Julia Seeliger

2017-01-01

Full Text Available Despite the continuous development of materials and techniques of adhesive bonding, the basic procedure remains relatively constant. The technique is based on three components: etching substance, adhesive system, and composite material. The use of etchants during bonding orthodontic brackets carries the risk of damage to the enamel. Therefore, the article examines the effect of the manner of enamel etching on its thickness before and after orthodontic treatment. The study was carried out in vitro on a group of 80 teeth. It was divided into two subgroups of 40 teeth each. The procedure of enamel etching was performed under laboratory conditions. In the first subgroup, the classic method of enamel etching and the fifth-generation bonding system were used. In the second subgroup, the seventh-generation (self-etching bonding system was used. In both groups, metal orthodontic brackets were fixed and the enamel was cleaned with a cutter fixed on the micromotor after their removal. Before and after the treatment, two-dimensional optical coherence tomography scans were performed. The enamel thickness was assessed on the two-dimensional scans. The average enamel thickness in both subgroups was not statistically significant.

Light-Cured Self-Etch Adhesives Undergo Hydroxyapatite-Triggered Self-Cure

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Liu, Y.; Bai, X.; Liu, Y.W.; Wang, Y.

2015-01-01

Light cure is a popular mode of curing for dental adhesives. However, it suffers from inadequate light delivery when the restoration site is less accessible, in which case a self-cure mechanism is desirable to salvage any compromised polymerization. We previously reported a novel self-cure system mediated by ethyl 4-(dimethylamino)-benzoate (4E) and hydroxyapatite (HAp). The present work aims to investigate if such self-cure phenomenon takes place in adhesives that underwent prior inadequate light cure and to elucidate if HAp released from the dental etching process is sufficient to trigger it. Model self-etch adhesives were formulated with various components, including bis[2-methacryloyloxy)ethyl]-phosphate (2MP) as acidic monomer and trimethylbenzoyl-diphenylphosphine oxide (TPO) as photoinitiator. In vitro evolution of degree of conversion (DC) of HAp-incorporated adhesives was monitored by infrared spectroscopy during light irradiation and dark storage. Selected adhesives were allowed to etch and extract HAp from enamel, light-cured in situ, and stored in the dark, after which Raman line mapping was used to obtain spatially resolved DC across the enamel-resin interface. Results showed that TPO+4E adhesives reached DC similar to TPO-only counterparts upon completion of light irradiation but underwent another round of initiation that boosted DC to ~100% regardless of HAp level or prior light exposure. When applied to enamel, TPO-only adhesives had ~80% DC in resin, which gradually descended to ~50% in enamel, whereas TPO+4E adhesives consistently scored ~80% DC across the enamel-resin interface. These observations suggest that polymerization of adhesives that underwent insufficient light cure is salvaged by the novel self-cure mechanism, and such salvaging effect can be triggered by HAp released from dental substrate during the etching process. PMID:26635279

Light-Cured Self-Etch Adhesives Undergo Hydroxyapatite-Triggered Self-Cure.

Science.gov (United States)

Liu, Y; Bai, X; Liu, Y W; Wang, Y

2016-03-01

Light cure is a popular mode of curing for dental adhesives. However, it suffers from inadequate light delivery when the restoration site is less accessible, in which case a self-cure mechanism is desirable to salvage any compromised polymerization. We previously reported a novel self-cure system mediated by ethyl 4-(dimethylamino)-benzoate (4E) and hydroxyapatite (HAp). The present work aims to investigate if such self-cure phenomenon takes place in adhesives that underwent prior inadequate light cure and to elucidate if HAp released from the dental etching process is sufficient to trigger it. Model self-etch adhesives were formulated with various components, including bis[2-methacryloyloxy)ethyl]-phosphate (2MP) as acidic monomer and trimethylbenzoyl-diphenylphosphine oxide (TPO) as photoinitiator. In vitro evolution of degree of conversion (DC) of HAp-incorporated adhesives was monitored by infrared spectroscopy during light irradiation and dark storage. Selected adhesives were allowed to etch and extract HAp from enamel, light-cured in situ, and stored in the dark, after which Raman line mapping was used to obtain spatially resolved DC across the enamel-resin interface. Results showed that TPO+4E adhesives reached DC similar to TPO-only counterparts upon completion of light irradiation but underwent another round of initiation that boosted DC to ~100% regardless of HAp level or prior light exposure. When applied to enamel, TPO-only adhesives had ~80% DC in resin, which gradually descended to ~50% in enamel, whereas TPO+4E adhesives consistently scored ~80% DC across the enamel-resin interface. These observations suggest that polymerization of adhesives that underwent insufficient light cure is salvaged by the novel self-cure mechanism, and such salvaging effect can be triggered by HAp released from dental substrate during the etching process. © International & American Associations for Dental Research 2015.

Clinical acceptability of two self-etch adhesive resins for the bonding of orthodontic brackets to enamel.

Science.gov (United States)

Schnebel, Bradley; Mateer, Scott; Maganzini, Anthony Louis; Freeman, Katherine

2012-12-01

To determine whether two self-adhesive resin cements, Clearfil SA and RelyX, can be used to successfully bond orthodontic brackets to enamel. Seventy extracted premolars were custom mounted, cleaned and randomly divided into three groups. In group 1 (control), orthodontic brackets were bonded to 25 premolars using the Transbond Plus and Transbond XT two step adhesive systerm adhesive. In group 2, brackets were bonded to 25 premolars using Clearfil SA. In group 3, brackets were bonded to 20 premolars using RelyX. The brackets were debonded using a universal testing machine and shear bond strengths recorded. After debonding, each tooth was examined under 20× magnification to evaluate the residual adhesive remaining. An ANOVA with Duncan's Multiple Range Test was used to determine whether there were significant differences in shear bond strength between the groups. A Kruskal-Wallis Test and a Bonferroni multiple comparison procedure were used to compare the bond failure modes (adhesive remnant index scores) between the groups. The mean shear bond strengths for the brackets bonded using Clearfil SA and RelyX were 5·930±1·840 and 3·334±1·953 MPa, respectively. Both were significantly lower than that for the brackets bonded using Transbond (7·875±3·611 MPa). Both self-etch adhesive resin cement groups showed a greater incidence of bracket failure at the enamel/adhesive interface while the Transbond group showed a higher incidence at the bracket/adhesive interface. The shear bond strengths of the self-etch adhesive resin cements may be inadequate to successfully bond orthodontic brackets to enamel.

Comparative study of etched enamel and dentin for the adhesion of composite resins with the Er:YAG 2,94 {mu}m laser and CO{sub 2} 9,6 {mu}m laser: morphological (SEM) and tensile bond strength analysis; Estudo comparativo do condicionamento do esmalte e dentina para a adesao de resinas compostas com os lasers Er:YAG 2,94 {mu}m e com o laser CO{sub 2} de 9,6 {mu}m: analise morfologica e de resistencia a tracao

Energy Technology Data Exchange (ETDEWEB)

Marraccini, Tarso Mugnai

2002-07-01

The aim of this study was to evaluate and compare the tensile bond strength of a composite resin adhered to the enamel and dentin which have received superficial irradiation with an Er:YAG laser (2.94 {mu}m) or with CO{sub 2} laser ( 9.6 {mu}m) and later on etched with the phosphoric acid at 35%. After the use of the adhesive system, resin cones were made on the etched surfaces by both lasers and tensile bond strength tests were performed. All samples were observed at the SEM - there was an increase of the degree of fusion and resolidification in the irradiated enamel and dentin samples with the CO{sub 2} laser (9.6 {mu}m), creating a vitrified layer with tiny craters. With the Er:YAG laser (2.94 {mu}m) there were typical morphological explosive microablation with the exposition of the tubules in the dentin.The surface acquired by the association of the CO{sub 2} laser ( 9.6 {mu}m) plus acid etching no longer presented the aspect of fusion being this layer completely removed. There were statistical significant differences among ali three methods of etching in the treatment of the enamel and dentin surface. The tensile bond strength test showed that etching of these enamel and dentin surfaces with acid exclusively (control group) presented great values, surpassing the values of the etching acquired with the Er:YAG laser (2.94 {mu}) plus acid or the CO{sub 2} laser (9.6 {mu}m) plus acid. With the parameters used in this experiment the Er:YAG laser (2.94 {mu}m) showed to be more effective than the CO{sub 2} laser (9.6 {mu}m) for the hard dental surfaces etching procedure. (author)

In situ synthesis carbonated hydroxyapatite layers on enamel slices with acidic amino acids by a novel two-step method.

Science.gov (United States)

Wu, Xiaoguang; Zhao, Xu; Li, Yi; Yang, Tao; Yan, Xiujuan; Wang, Ke

2015-09-01

In situ fabrication of carbonated hydroxyapatite (CHA) remineralization layer on an enamel slice was completed in a novel, biomimetic two-step method. First, a CaCO3 layer was synthesized on the surface of demineralized enamel using an acidic amino acid (aspartic acid or glutamate acid) as a soft template. Second, at the same concentration of the acidic amino acid, rod-like carbonated hydroxyapatite was produced with the CaCO3 layer as a sacrificial template and a reactant. The morphology, crystallinity and other physicochemical properties of the crystals were characterized using field emission scanning electron microscopy (FESEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and energy-dispersive X-ray analysis (EDAX), respectively. Acidic amino acid could promote the uniform deposition of hydroxyapatite with rod-like crystals via absorption of phosphate and carbonate ions from the reaction solution. Moreover, compared with hydroxyapatite crystals coated on the enamel when synthesized by a one-step method, the CaCO3 coating that was synthesized in the first step acted as an active bridge layer and sacrificial template. It played a vital role in orienting the artificial coating layer through the template effect. The results show that the rod-like carbonated hydroxyapatite crystals grow into bundles, which are similar in size and appearance to prisms in human enamel, when using the two-step method with either aspartic acid or acidic glutamate (20.00 mmol/L). Copyright © 2015 Elsevier B.V. All rights reserved.

Acid-catalyzed kinetics of indium tin oxide etching

Energy Technology Data Exchange (ETDEWEB)

Choi, Jae-Hyeok; Kim, Seong-Oh; Hilton, Diana L. [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); Cho, Nam-Joon, E-mail: njcho@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Centre for Biomimetic Sensor Science, Nanyang Technological University, 50 Nanyang Drive, 637553 (Singapore); School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, 637459 (Singapore)

2014-08-28

We report the kinetic characterization of indium tin oxide (ITO) film etching by chemical treatment in acidic and basic electrolytes. It was observed that film etching increased under more acidic conditions, whereas basic conditions led to minimal etching on the time scale of the experiments. Quartz crystal microbalance was employed in order to track the reaction kinetics as a function of the concentration of hydrochloric acid and accordingly solution pH. Contact angle measurements and atomic force microscopy experiments determined that acid treatment increases surface hydrophilicity and porosity. X-ray photoelectron spectroscopy experiments identified that film etching is primarily caused by dissolution of indium species. A kinetic model was developed to explain the acid-catalyzed dissolution of ITO surfaces, and showed a logarithmic relationship between the rate of dissolution and the concentration of undisassociated hydrochloric acid molecules. Taken together, the findings presented in this work verify the acid-catalyzed kinetics of ITO film dissolution by chemical treatment, and support that the corresponding chemical reactions should be accounted for in ITO film processing applications. - Highlights: • Acidic conditions promoted indium tin oxide (ITO) film etching via dissolution. • Logarithm of the dissolution rate depended linearly on the solution pH. • Acid treatment increased ITO surface hydrophilicity and porosity. • ITO film etching led to preferential dissolution of indium species over tin species.

Human enamel structure studied by high resolution electron microscopy

International Nuclear Information System (INIS)

Wen, S.L.

1989-01-01

Human enamel structural features are characterized by high resolution electron microscopy. The human enamel consists of polycrystals with a structure similar to Ca10(PO4)6(OH)2. This article describes the structural features of human enamel crystal at atomic and nanometer level. Besides the structural description, a great number of high resolution images are included. Research into the carious process in human enamel is very important for human beings. This article firstly describes the initiation of caries in enamel crystal at atomic and unit-cell level and secondly describes the further steps of caries with structural and chemical demineralization. The demineralization in fact, is the origin of caries in human enamel. The remineralization of carious areas in human enamel has drawn more and more attention as its potential application is realized. This process has been revealed by high resolution electron microscopy in detail in this article. On the other hand, the radiation effects on the structure of human enamel are also characterized by high resolution electron microscopy. In order to reveal this phenomenon clearly, a great number of electron micrographs have been shown, and a physical mechanism is proposed. 26 references

In vitro wear of four ceramic materials and human enamel on enamel antagonist.

Science.gov (United States)

Nakashima, Jun; Taira, Yohsuke; Sawase, Takashi

2016-06-01

The purpose of the present study was to evaluate the wear of four different ceramics and human enamel. The ceramics used were lithium disilicate glass (e.max Press), leucite-reinforced glass (GN-Ceram), yttria-stabilized zirconia (Aadva Zr), and feldspathic porcelain (Porcelain AAA). Hemispherical styli were fabricated with these ceramics and with tooth enamel. Flattened enamel was used for antagonistic specimens. After 100,000 wear cycles of a two-body wear test, the height and volume losses of the styli and enamel antagonists were determined. The mean and standard deviation for eight specimens were calculated and statistically analyzed using a non-parametric (Steel-Dwass) test (α = 0.05). GN-Ceram exhibited greater stylus height and volume losses than did Porcelain AAA. E.max Press, Porcelain AAA, and enamel styli showed no significant differences, and Aadva Zr exhibited the smallest stylus height and volume losses. The wear of the enamel antagonist was not significantly different among GN-Ceram, e.max Press, Porcelain AAA, and enamel styli. Aadva Zr resulted in significantly lower wear values of the enamel antagonist than did GN-Ceram, Porcelain AAA, and enamel styli. In conclusion, leucite-reinforced glass, lithium disilicate glass, and feldspathic porcelain showed wear values closer to those for human enamel than did yttria-stabilized zirconia. © 2016 Eur J Oral Sci.

Comparison of the shear bond strength of self-adhesive resin cements to enamel and dentin with different protocol of application.

Science.gov (United States)

Moghaddas, Mohammad Javad; Hossainipour, Zahra; Majidinia, Sara; Ojrati, Najmeh

2017-08-01

The aim of the present study was to determine the shear bond strength of self-adhesive resin cements to enamel and dentin with and without surface treatments, and compare them with conventional resin cement as the control group. In this experimental study, buccal and lingual surface of the thirty sound human premolars were polished in order to obtain a flat surface of enamel (E) in buccal, and dentin (D) in lingual. Sixty feldspathic ceramic blocks (2×3×3 mm) were prepared and randomly divided into six groups (n=10). Each block was cemented to the prepared surface (30 enamel and 30 dentin surface) according to different protocol: E1 and D1; RelyX ARC as control group, E2, D2; RelyX Unicem, E3, D3; acid etching +RelyX Unicem. The specimens were termocycled and subjected to shear forces by a universal testing machine at a cross head speed of 0.5 mm/min. The mode of fracture were evaluated by stereomicroscope. Data were analyzed with descriptive statistical methods using SPSS version 15. One-way ANOVA, and post hoc Tukey tests were used to compare bond strengths between the groups with different adhesives at α=0.05. Statistical analysis showed no significant differences within the enamel subgroups, but there were significant differences within the dentinal subgroups, and statistically significant differences were found between the groups D1and D3 (p=0.02). Comparison between similar enamel and dentinal subgroups showed that there was a significant difference just between the subgroups E3 and D3 (p=0.01). Elective etching of enamel did not lead to significant increase in the shear bond strength of RelyX Unicem in comparison to RelyX ARC. On the other hand, elective etching of dentin reduces the bond strength of RelyX Unicem with the dentin.

Is laser conditioning a valid alternative to conventional etching for aesthetic brackets?

Science.gov (United States)

Sfondrini, M F; Calderoni, G; Vitale, M C; Gandini, P; Scribante, A

2018-03-01

ER:Yag lasers have been described as a more conservative alternative to conventional acid-etching enamel conditioning technique, when bonding conventional metallic orthodontic brackets. Since the use of aesthetic orthodontic brackets is constantly increasing, the purpose of the present report has been to test laser conditioning with different aesthetic brackets. Study Design: Five different aesthetic brackets (microfilled copolymer, glass fiber, sapphire, polyoxymethylene and sintered ceramic) were tested for shear bond strength and Adhesive Remnant Index scores using two different enamel conditioning techniques (acid etching and ER:Yag laser application). Two hundred bovine incisors were extracted, cleaned and embedded in resin. Specimens were then divided into 10 groups with random tables. Half of the specimens were conditioned with conventional orthophosphoric acid gel, the other half with ER:Yag laser. Different aesthetic brackets (microfilled copolymer, glass fiber, sapphire, polyoxymethylene and sintered ceramic) were then bonded to the teeth. Subsequently all groups were tested in shear mode with a Universal Testing Machine. Shear bond strength values and adhesive remnant index scores were recorded. Statistical analysis was performed. When considering conventional acid etching technique, sapphire, polyoxymethylene and sintered ceramic brackets exhibited the highest SBS values. Lowest values were reported for microfilled copolymer and glass fiber appliances. A significant decrease in SBS values after laser conditioning was reported for sapphire, polyoxymethylene and sintered ceramic brackets, whereas no significant difference was reported for microfilled copolymer and glass fiber brackets. Significant differences in ARI scores were also reported. Laser etching can significantly reduce bonding efficacy of sapphire, polyoxymethylene and sintered ceramic brackets.

Microtensile bond strength of contemporary adhesives to primary enamel and dentin.

Science.gov (United States)

Marquezan, Marcela; da Silveira, Bruno Lopes; Burnett, Luiz Henrique; Rodrigues, Célia Regina Martins Delgado; Kramer, Paulo Floriani

2008-01-01

The purpose of this study was to assess bond strength of three self-etching and two total-etch adhesive systems bonded to primary tooth enamel and dentin. Forty extracted primary human molars were selected and abraded in order to create flat buccal enamel and occlusal dentin surfaces. Teeth were assigned to one of the adhesive systems: Adper Scotch Bond Multi Purpose, Adper Single Bond 2, Adper Prompt L-Pop, Clearfil SE Bond and AdheSE. Immediately to adhesive application, a composite resin (Filtek Z250) block was built up. After 3 months of water storage, each sample was sequentially sectioned in order to obtain sticks with a square cross-sectional area of about 0.72 mm2. The specimens were fixed lengthways to a microtensile device and tested using a universal testing machine with a 50-N load cell at a crosshead speed of 0.5 mm/min. Microtensile bond strength values were recorded in MPa and compared by Analysis of Variance and the post hoc Tukey test (a = 0.05). In enamel, Clearfil SE Bond presented the highest values, followed by Adper Single Bond 2, AdheSE and Adper Scotch Bond Multi Purpose, without significant difference. The highest values in dentin were obtained with Adper Scotch Bond Multi Purpose and all other adhesives did not present significant different values from that, except Adper Prompt L-Pop that achieved the lowest bond strength in both substrates. Adper Scotch Bond Multi Purpose and Adper Single Bond 2 presented significantly lower values in enamel than in dentin although all other adhesives presented similar results in both substrates. contemporary adhesive systems present similar behaviors when bonded to primary teeth, with the exception of the one-step self-etching system; and self-etching systems can achieve bond strength values as good in enamel as in dentin of primary teeth.

Self-etching ceramic primer versus hydrofluoric acid etching: Etching efficacy and bonding performance.

Science.gov (United States)

El-Damanhoury, Hatem M; Gaintantzopoulou, Maria D

2018-01-01

This study assessed the effect of pretreatment of hybrid and glass ceramics using a self-etching primer on the shear bond strength (SBS) and surface topography, in comparison to pretreatment with hydrofluoric acid and silane. 40 rectangular discs from each ceramic material (IPS e.max CAD;EM, Vita Mark II;VM, Vita Enamic;VE), were equally divided (n=10) and assigned to one of four surface pretreatment methods; etching with 4.8% hydrofluoric acid followed by Monobond plus (HFMP), Monobond etch & prime (Ivoclar Vivadent) (MEP), No treatment (NT) as negative control and Monobond plus (Ivoclar Vivadent) with no etching (MP) as positive control. SBS of resin cement (Multilink-N, Ivoclar Vivadent) to ceramic surfaces was tested following a standard protocol. Surface roughness was evaluated using an Atomic force microscope (AFM). Surface topography and elemental analysis were analyzed using SEM/EDX. Data were analyzed with two-way analysis of variance (ANOVA) and post-hoc Bonferroni test at a significance level of α=0.05. Pretreatment with HFMP resulted in higher SBS and increased surface roughness in comparison to MEP and MP. Regardless the method of surface pretreatment, the mean SBS values of EM ceramic was significantly higher (pceramics for resin-luting cementation. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Shear bond strength of three adhesive systems to enamel and dentin of permanent teeth

Directory of Open Access Journals (Sweden)

Niloofar Shadman

2012-01-01

Full Text Available Background and Aims: The purpose of this experimental study was to investigate the shear bond strength of three new adhesive systems to enamel and dentin of permanent human teeth using three new etch and rinse and self-etch adhesive systems.Materials and Methods: Sixty intact caries-free third molars were selected and randomly divided into 6 groups. Flat buccal and lingual enamel and dentin surfaces were prepared and mounted in the acrylic resin perpendicular to the plan of the horizon. Adhesives used in this study were Tetric N-Bond, AdheSE and AdheSE-One F (Ivoclar/Vivadent, Schaan, Liechtenstein. The adhesives were applied on the surfaces and cured with quartz tungsten halogen curing unit (600 mW/cm2 intensity for 20 s. After attaching composite to the surfaces and thermocycling (500 cycles, 5-55ºC, shear bond strength was measured using a universal testing machine at a crosshead speed of 0.5 mm/min. The failure modes were examined under a stereomicroscope. The data were statistically analyzed using T-test, one-way ANOVA, Tukey and Fisher's exact tests.Results: In enamel, Tetric N-Bond (28.57±4.58 MPa and AdheSE (21.97±7.6 MPa had significantly higher bond strength than AdheSE-One F (7.16±2.09 MPa (P0.05.Conclusion: Shear bond strength to dentin in Tetric N-Bond (etch and rinse system( was higher than self-etch adhesives (AdheSE and AdheSE-One F. The bond strength to enamel and dentin in two-step self-etch (AdheSE was higher than one-step self-etch (AdheSE-One F.

Evaluation of human dental loss caused by carbamide peroxide bleacher compared with phosphoric acid conditioning - radioactive method; Avaliacao da perda dental humana com o uso do clareador peroxido de carbamida comparado ao condicionamento com acido fosforico - metodo radiometrico

Energy Technology Data Exchange (ETDEWEB)

Adachi, Eduardo Makoto; Yousseff, Michel Nicolau [Sao Paulo Univ., SP (Brazil). Faculdade de Odontologia. Dept. de Dentistica; Saiki, Mitiko [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Lab. de Analise por Ativacao Neutronica

2002-07-01

The radiometric method was applied to the evaluation of dental loss caused by carbamide peroxide when it is applied on the surface layers of enamel and dentin tissues. Also the dental loss caused by the etching with 37% phosphoric acid procedure used in aesthetic restoration was assessed for comparison with those results obtained. The tooth samples irradiated with a P standard in a thermal neutron flux of the nuclear reactor were placed in contact with 10% carbamide peroxide or with 37% phosphoric acid solution. The radioactivity of {sup 32} P transferred from the radioactive teeth to the bleaching gel or to etching acid was measured using a Geiger Muller detector to calculate the mass of P removed in this treatment and losses were calculated after obtaining their P concentrations. Results obtained indicated that enamel and dentin exposed to carbamide peroxide bleaching agent lose phosphorus. The extent of enamel loss was smaller than that obtained for dentin. In the case of acid etching, there was no difference between the results obtained for enamel and dentin loss. Also the dentin loss obtained after a treatment of 30 applications of 10% carbamide peroxide was the same magnitude of that one application of 37% phosphoric acid. (author)

Microtensile Bond Strength and Micromorphology of Bur-cut Enamel Using Five Adhesive Systems.

Science.gov (United States)

Vinagre, Alexandra; Ramos, João; Messias, Ana; Marques, Fernando; Caramelo, Francisco; Mata, António

2015-04-01

This study compared the microtensile bond strengths (μTBS) of two etch-and-rinse (ER) (OptiBond FL [OBFL]; Prime & Bond NT [PBNT]) and three self-etching (SE) (Clearfil SE Bond [CSEB]; Xeno III [XIII]; Xeno V+ [XV+]) adhesives systems to bur-prepared human enamel considering active (AA) and passive (PA) application of the self-etching systems. Ninety-six enamel surfaces were prepared with a medium-grit diamond bur and randomly allocated into 8 groups to receive adhesive restorations: G1: OBFL; G2: PBNT; G3: CSEB/PA; G4: CSEB/ AA; G5: XIII/PA; G6: XIII/AA; G7: XV+/PA; G8: XV+/AA. After composite buildup, samples were sectioned to obtain a total of 279 bonded sticks (1 mm2) that were submitted to microtensile testing (μTBS; 0.5 mm/min) after 24-h water storage (37°C). Etching patterns and adhesive interfacial ultramorphology were also evaluated with confocal laser scanning (CLSM) and scanning electron microscopy (SEM). Data was analyzed with one-way ANOVA (α = 0.05). Weibull probabilistic distribution was also determined. Regarding μTBS, both adhesive system and application mode yielded statistically significant differences (p systems together with CSEB/AA and XIII/PA recorded the highest and statistically similar bond strength results. XV+ presented very low bond strength values, regardless of the application mode. Among self-etching adhesives, CSEB produced significantly higher μTBS values when applied actively. Qualitative evaluation by SEM and CLSM revealed substantial differences between groups both in adhesive interfaces and enamel conditioning patterns. ER and SE adhesive systems presented distinctive bond strengths to bur-cut enamel. The application mode effect was adhesive dependent. Active application improved etching patterns and resin interfaces micromorphology.

[Effects of tooth whitening agents and acidic drinks on the surface properties of dental enamel].

Science.gov (United States)

Chen, Xiaoling; Chen, Zhiqun; Lin, Yao; Shao, Jinquan; Yin, Lu

2013-10-01

Using tooth whitening agents (bleaching clip) in vitro and acidic drinks, we conducted a comparative study of the changes in enamel surface morphology, Ca/P content, and hardness. Tooth whitening glue pieces, cola, and orange juice were used to soak teeth in artificial saliva in vitro. Physiological saline was used as a control treatment. The morphology of the four groups was observed under a scanning electron microscope (SEM) immediately after the teeth were soaked for 7 and 14 d. The changes in Ca/P content and microhardness were analyzed. The enamel surfaces of the teeth in the three test groups were demineralized. The Ca/P ratio and the average microhardness were significantly lower than those of the control group immediately after the teeth were soaked (P 0.05). Bleaching agents caused transient demineralization of human enamel, but these agents could induce re-mineralization and repair of enamel over time. Demineralization caused by bleaching covered a relatively normal range compared with acidic drinks and daily drinking.

Adhesive interfaces of enamel and dentin prepared by air-abrasion at different distances

International Nuclear Information System (INIS)

Chinelatti, Michelle Alexandra; Andreolli do Amaral, Thais Helena; Borsatto, Maria Cristina; Palma-Dibb, Regina Guenka; Corona, Silmara Aparecida Milori

2007-01-01

The purpose of this study was to analyse, by scanning electron microscopy (SEM), the morphology of enamel and dentin/adhesive interfaces in cavities prepared by air-abrasion at different working distances. Thirty sound third human molars were selected and, on both their buccal and lingual surfaces, class V cavities were prepared by air-abrasion, at 2-, 4-, 6-, 8- and 10-mm working distances, or high-speed bur (control group). After preparation, all cavities were etched with 35% phosphoric acid gel and restored with Single Bond/Filtek Z-250. Buccal and lingual surfaces were separated and restorations sectioned in a buccolingual direction, providing two sections of each cavity, which were analysed by scanning electron microscopy. It was observed that the distances of 6 and 8 mm promoted more homogeneous dentin/adhesive interfaces, with tags formation, and more uniform for enamel, which were similar to the control group. It may be concluded that the air-abrasion working distance can influence the morphology of enamel and dentin/adhesive interfaces, and the intermediate distances provided better adhesive interfaces

Quantitative analysis of enamel on debonded orthodontic brackets.

Science.gov (United States)

Cochrane, Nathan J; Lo, Thomas W G; Adams, Geoffrey G; Schneider, Paul M

2017-09-01

Iatrogenic damage to the tooth surface in the form of enamel tearouts can occur during removal of fixed orthodontic appliances. The aim of this study was to assess debonded metal and ceramic brackets attached with a variety of bonding materials to determine how frequently this type of damage occurs. Eighty-one patients close to finishing fixed orthodontic treatment were recruited. They had metal brackets bonded with composite resin and a 2-step etch-and-bond technique or ceramic brackets bonded with composite resin and a 2-step etch-and- bond technique, and composite resin with a self-etching primer or resin-modified glass ionomer cement. Debonded brackets were examined by backscattered scanning electron microscopy with energy dispersive x-ray spectroscopy to determine the presence and area of enamel on the base pad. Of the 486 brackets collected, 26.1% exhibited enamel on the bonding material on the bracket base pad. The incidences of enamel tearouts for each group were metal brackets, 13.3%; ceramic brackets, 30.2%; composite resin with self-etching primer, 38.2%; and resin-modified glass ionomer cement, 21.2%. The percentage of the bracket base pad covered in enamel was highly variable, ranging from 0% to 46.1%. Enamel damage regularly occurred during the debonding process with the degree of damage being highly variable. Damage occurred more frequently when ceramic brackets were used (31.9%) compared with metal brackets (13.3%). Removal of ceramic brackets bonded with resin-modified glass ionomer cement resulted in less damage compared with the resin bonding systems. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Marginal microleakage in vitro study on class V cavities prepared with Er:YAG laser and etched with acid or etched with Er:YAG laser and acid; Estudo in vitro da microinfiltracao marginal em cavidades classe V preparadas com laser de Er:YAG e condicionadas com acido ou com laser de Er:YAG e acido

Energy Technology Data Exchange (ETDEWEB)

Tavares, Henrique Dutra Simoes

2001-07-01

Microleakage at the interface between the teeth and the restorative materials remains a problem with composite resin restorations. Microleakage at the gingival margins of class V cavities restorations still challenge as they are usually placed in dentin and/or cementum. Previous studies have shown that the cavity preparation with Er:YAG laser is possible. It has been reported that Er:YAG laser has ability to create irregular surface providing micromechanical retention for adhesive dental restorative materials and to improve marginal sealing. The purpose of this in vitro study was to evaluate the marginal microleakage on class V cavities prepared with Er:YAG laser and etched with acid or with Er:YAG laser and acid, in compared to those prepared and etched conventionally. Thirty human molars were divided into three groups, namely: group I - prepared with Er:YAG laser (KaVo KEY Laser II - Germany) and etched with 37% phosphoric acid; group II - prepared with Er:YAG laser and etched with Er:YAG laser and 37% phosphoric acid; group III (control group) - prepared with high speed drill and etched with 37% phosphoric acid. All cavities were treated with same adhesive system (Single Bond - 3M) and restored with the composite resin (Z100 - 3M), according to the manufacturer's instructions. The specimens were stored at 37 deg C in water for 24 hours, polished with Sof-Lex discs (3M), thermally stressed, sealed with a nail polish coating except for the area of the restoration and 1 mm around it, and immersed in a 50% aqueous solution of silver nitrate for 24 hours. After that, the specimens were rinsed in water, soaked in a photodeveloping solution and exposed to a fluorescent light for 8 hours. The teeth were embedded in an autopolymerizing resin and sectioned longitudinally using a diamond saw microtome under running water. The sections were photographed. The microleakage at the occlusal cavity and at the gingival margins of each specimen was evaluated with scores (0-3) by

Marginal microleakage in vitro study on class V cavities prepared with Er:YAG laser and etched with acid or etched with Er:YAG laser and acid; Estudo in vitro da microinfiltracao marginal em cavidades classe V preparadas com laser de Er:YAG e condicionadas com acido ou com laser de Er:YAG e acido

Energy Technology Data Exchange (ETDEWEB)

Tavares, Henrique Dutra Simoes

2001-07-01

Microleakage at the interface between the teeth and the restorative materials remains a problem with composite resin restorations. Microleakage at the gingival margins of class V cavities restorations still challenge as they are usually placed in dentin and/or cementum. Previous studies have shown that the cavity preparation with Er:YAG laser is possible. It has been reported that Er:YAG laser has ability to create irregular surface providing micromechanical retention for adhesive dental restorative materials and to improve marginal sealing. The purpose of this in vitro study was to evaluate the marginal microleakage on class V cavities prepared with Er:YAG laser and etched with acid or with Er:YAG laser and acid, in compared to those prepared and etched conventionally. Thirty human molars were divided into three groups, namely: group I - prepared with Er:YAG laser (KaVo KEY Laser II - Germany) and etched with 37% phosphoric acid; group II - prepared with Er:YAG laser and etched with Er:YAG laser and 37% phosphoric acid; group III (control group) - prepared with high speed drill and etched with 37% phosphoric acid. All cavities were treated with same adhesive system (Single Bond - 3M) and restored with the composite resin (Z100 - 3M), according to the manufacturer's instructions. The specimens were stored at 37 deg C in water for 24 hours, polished with Sof-Lex discs (3M), thermally stressed, sealed with a nail polish coating except for the area of the restoration and 1 mm around it, and immersed in a 50% aqueous solution of silver nitrate for 24 hours. After that, the specimens were rinsed in water, soaked in a photodeveloping solution and exposed to a fluorescent light for 8 hours. The teeth were embedded in an autopolymerizing resin and sectioned longitudinally using a diamond saw microtome under running water. The sections were photographed. The microleakage at the occlusal cavity and at the gingival margins of each specimen was evaluated with scores (0

Effects of conditioners on microshear bond strength to enamel after carbamide peroxide bleaching and/or casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) treatment.

Science.gov (United States)

Adebayo, O A; Burrow, M F; Tyas, M J

2007-11-01

To evaluate (a) the enamel microshear bond strength (MSBS) of a universal adhesive and (b) the effects of conditioning with a self-etching primer adhesive with/without prior bleaching and/or casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) application. Thirty-five molars were cut into four sections, assigned randomly to four groups (no treatment; 16% carbamide peroxide bleaching; CPP-ACP-containing paste (Tooth Mousse, TM); bleaching and TM) and treated accordingly. Specimens were divided into two for bonding with either a self-etching primer (Clearfil SE Bond, CSE) or a total-etch adhesive (Single Bond, SB). Specimens for CSE bonding were subdivided for one of four preconditioning treatments (no conditioning; 30-40% phosphoric acid (PA); 15% EDTA; 20% polyacrylic acid conditioner (Cavity conditioner, CC) and treated. The adhesives were applied and resin composite bonded to the enamel using microtubes (internal diameter 0.75mm). Bonds were stressed in shear until failure, mean MSBS calculated and data analysed using ANOVA with Tukey's HSD test (alpha=0.05). The modes of bond failure were assessed and classified. Two-way ANOVA revealed significant differences between treatments (Padhesive system on treated enamel may significantly improve bond strengths.

Salivary a-amylase protects enamel surface against acid induced softening

DEFF Research Database (Denmark)

Lazovic, Maja Bruvo; Moe, Dennis; Kirkeby, Svend

Objectives: Recently we have demonstrated individual differences in protection against acid-induced enamel softening offered by experimentally developed saliva pellicles. Although ethnicity seemed to be related to protection level, the saliva proteins responsible for the differences were not iden......Objectives: Recently we have demonstrated individual differences in protection against acid-induced enamel softening offered by experimentally developed saliva pellicles. Although ethnicity seemed to be related to protection level, the saliva proteins responsible for the differences were......, and one Chinese. After collection, saliva was dialysed and lyophilised and re-dissolved at 0.5% in Type I water. Next, four polished bovine enamel specimens were immersed into each sample under gentle and constant shaking for 12 hours. Last, specimens were exposed to an erosive challenge of pH 2.3 for 4......-TOF mass fingerprinting following trypsin digestion. Each persistent peak in the HPLC chromatograms was related to the protective effect against acid-induced enamel softening obtained by the corresponding saliva sample by multiple regression analysis. Results: One peak identified as a-amylase had...

Shear bond strength of hydrophilic adhesive systems to enamel.

Science.gov (United States)

Hara, A T; Amaral, C M; Pimenta, L A; Sinhoreti, M A

1999-08-01

To compare the enamel shear bond strength of four hydrophilic adhesive systems: one multiple-bottle (Scotchbond Multi-Purpose Plus), two one-bottle (Stae, Single Bond) and one self-etching (Etch & Prime). 120 bovine incisor teeth were obtained, embedded in polyester resin, polished to 600 grit to form standardized enamel surfaces, and randomly assigned to four groups (n = 30). Each adhesive system was used on enamel according to the manufacturer's instructions, and resin-based composite (Z100) cylinders with 3 mm diameter and 5 mm height were bonded. Specimens were stored in humid environment for 1 week, and bond strength was determined using a universal testing machine, at a crosshead speed of 0.5 mm/minute. The mean shear bond strength values (MPa +/- SD) were: Single Bond: 24.28 +/- 5.27 (a); Scotchbond Multi-Purpose Plus: 21.18 +/- 4.35 (ab); Stae: 19.56 +/- 4.71 (b); Etch & Prime 3.0: 15.13 +/- 4.92 (c). ANOVA revealed significant difference in means (P < 0.01) and Tukey's test showed the statistical differences that are expressed by different letters for each group. It could be concluded that the self-etching adhesive system did not provide as good a bond to enamel surface, as did the one- and multiple-bottle systems.

Immediate adhesive properties to dentin and enamel of a universal adhesive associated with a hydrophobic resin coat.

Science.gov (United States)

Perdigão, J; Muñoz, M A; Sezinando, A; Luque-Martinez, I V; Staichak, R; Reis, A; Loguercio, A D

2014-01-01

To evaluate the effect of acid etching and application of a hydrophobic resin coat on the enamel/dentin bond strengths and degree of conversion (DC) within the hybrid layer of a universal adhesive system (G-Bond Plus [GB]). A total of 60 extracted third molars were divided into four groups for bond-strength testing, according to the adhesive strategy: GB applied as a one-step self-etch adhesive (1-stepSE); GB applied as in 1-stepSE followed by one coat of the hydrophobic resin Heliobond (2-stepSE); GB applied as a two-step etch-and-rinse adhesive (2-stepER); GB applied as in 2-stepER followed by one coat of the hydrophobic resin Heliobond (3-stepER). There were 40 teeth used for enamel microshear bond strength (μSBS) and DC; and 20 teeth used for dentin microtensile bond strength (μTBS) and DC. After restorations were constructed, specimens were stored in water (37°C/24 h) and then tested at 0.5 mm/min (μTBS) or 1.0 mm/min (μSBS). Enamel-resin and dentin-resin interfaces from each group were evaluated for DC using micro-Raman spectroscopy. Data were analyzed with two-way analysis of variance for each substrate and the Tukey test (α=0.05). For enamel, the use of a hydrophobic resin coat resulted in statistically significant higher mean enamel μSBS only for the ER strategy (3-stepER vs 2-stepER, penamel etching technique, because it improves bond strengths to enamel when applied with the ER strategy and to dentin when used with the SE adhesion strategy. The application of a hydrophobic resin coat may improve DC in resin-dentin interfaces formed with either the SE or the ER strategy. On enamel, DC may benefit from the application of a hydrophobic resin coat over 1-stepSE adhesives.

Indentation Damage and Crack Repair in Human Enamel*

OpenAIRE

Rivera, C.; Arola, D.; Ossa, A.

2013-01-01

Tooth enamel is the hardest and most highly mineralized tissue in the human body. While there have been a number of studies aimed at understanding the hardness and crack growth resistance behavior of this tissue, no study has evaluated if cracks in this tissue undergo repair. In this investigation the crack repair characteristics of young human enamel were evaluated as a function of patient gender and as a function of the distance from the Dentin Enamel Junction (DEJ). Cracks were introduced ...

Nanoindentation creep behavior of human enamel.

Science.gov (United States)

He, Li-Hong; Swain, Michael V

2009-11-01

In this study, the indentation creep behavior of human enamel was investigated with a nanoindentation system and a Berkovich indenter at a force of 250 mN with one-step loading and unloading method. A constant hold period of 900 s was incorporated into each test at the maximum load as well at 5 mN minimum load during unloading. The indentation creep at the maximum load and creep recovery at the minimum load was described with a double exponential function and compared with other classic viscoelastic models (Debye/Maxwell and Kohlrausch-Williams-Watts). Indentation creep rate sensitivity, m, of human enamel was measured for the first time with a value of approximately 0.012. Enamel displayed both viscoelastic and viscoplastic behavior similar to that of bone. These results indicate that, associated with entrapment of particulates between teeth under functional loading and sliding wear conditions, the enamel may inelastically deform but recover upon its release. This behavior may be important in explaining the excellent wear resistance, antifatigue, and crack resistant abilities of natural tooth structure. (c) 2008 Wiley Periodicals, Inc.

Enamel microstructure and microstrain in the fracture of human and pig molar cusps.

Science.gov (United States)

Popowics, T E; Rensberger, J M; Herring, S W

2004-08-01

The role of microstructure in enamel strain and breakage was investigated in human molar cusps and those of the pig, Sus scrofa. Rosette strain gauges were affixed to cusp surfaces (buccal human M3, n=15, and lingual pig M1, n=13), and a compressive load was applied to individual cusps using an MTS materials testing machine. Load and strain data were recorded simultaneously until cusp fracture, and these data were used to estimate enamel stresses, principal strains, and stiffness. Fractured and polished enamel fragments were examined in multiple planes using scanning electron microscopy (SEM). Human cusp enamel showed greater stiffness than pig enamel (P=0.02), and tensile stress at yield was higher (17.9 N/mm2 in humans versus 8.9 N/mm2 in pigs, P=0.06). SEM revealed enamel rod decussation in both human and pig enamel; however, only pig enamel showed a decussation plane between rod and inter-rod crystallites. Human inter-rod enamel was densely packed between rods, whereas in pig enamel, inter-rod enamel formed partitions between rows of enamel rods. Overall, human enamel structure enabled molar cusps to withstand horizontal tensile stress during both elastic and plastic phases of compressive loading. In contrast, pig cusp enamel was less resistant to horizontal tensile stresses, but appeared to fortify the enamel against crack propagation in multiple directions. These structural and biomechanical differences in cusp enamel are likely to reflect species-level differences in occlusal function.

Evaluation of human enamel surfaces treated with theobromine: a pilot study.

Science.gov (United States)

Kargul, Betul; Özcan, Mutlu; Peker, Sertac; Nakamoto, Tetsuo; Simmons, William B; Falster, Alexander U

2012-01-01

The objectives of this in-vitro study were to investigate the effect of theobromine, which is the principle xanthine species in Theobroma cacao, at two concentrations on the surface hardness and topography of human enamel. Twenty-four freshly extracted human third molars were collected and stored in distilled water with 0.1% thymol solution at room temperature prior to the experiments. The enamel specimens were treated with one coat of theobromine at two concentrations (100 mg/l or 200 mg/l in distilled water) for 5 min. Enamel surfaces in the control group received no theobromine. They were then kept in distilled water for 1 week and subjected to SEM analysis. The specimens were demineralised by storing them in acidic hydroxyethylcellulose for three days. After baseline microhardness measurements, they were incubated either in 100 or 200 mg/l theobromine for 5 min. The control group was kept in distilled water. After washing the specimens under distilled water, they were kept in a remineralising solution for 18 h. Microhardness of the enamel surface was initially determined for each specimen before artificial demineralisation. After demineralisation, the experimental groups were incubated in 100 mg or 200 mg theobromine and control-group specimens were placed in remineralising solution. Enamel surfaces of the untreated control group presented a generally smooth and slightly hummocky surface with small lines of pits. Specimens treated with theobromine showed differences between the two concentrations. The group treated with 200 mg/l solution for 5 min showed a greater quantity of globules on enamel than did specimens treated with 100 mg/l solution. As shown by the microhardness values, a consistent and remarkable protection of the enamel surface was found with the application of theobromine.

Influence of different conditioning methods on the shear bond strength of novel light-curing nano-ionomer restorative to enamel and dentin.

Science.gov (United States)

Korkmaz, Yonca; Ozel, Emre; Attar, Nuray; Ozge Bicer, Ceren

2010-11-01

The purpose of this study was to investigate shear bond strength (SBS) between a light-curing nano-ionomer restorative and enamel or dentin after acid etching, after erbium:yttrium-aluminum-garnet (Er:YAG) laser etching, or after combined treatment. Forty third molars were selected, the crowns were sectioned, and 80 tooth slabs were obtained. The specimens were assigned to two groups, which were divided into four subgroups(n = 10). Group 1 [enamel (e)], treated with 37% phosphoric acid (A) + Ketac nano-primer (K); group 2 [dentin (d)], (A) + (K); group 3(e), Er:YAG laser etching (L) + (A) + (K); group 4(d), (L) + (A) + (K); group 5(e), (L) + (K); group 6(d), (L) + (K); group 7(e), (K); group 8(d), (K). The SBS of the specimens was measured with a universal test machine (1 mm/min). Data were analyzed by independent samples t-test, one-way analysis of variance (ANOVA) and a post-hoc Duncan test (p 0.05). Group 7 exhibited higher SBS values than those of groups 3 and 5 (p 0.05). No difference was observed between groups 2 and 4 (p > 0.05). However, group 2 presented higher SBSs than did group 6 (p adhesion of the light-curing nano-ionomer restorative to both enamel and dentin.

Enamel Wetness Effects on Microshear Bond Strength of Different Bonding Agents (Adhesive Systems): An in vitro Comparative Evaluation Study.

Science.gov (United States)

Kulkarni, Girish; Mishra, Vinay K

2016-05-01

The purpose of this study was to compare the effect of enamel wetness on microshear bond strength using different adhesive systems. To evaluate microshear bond strength of three bonding agents on dry enamel; to evaluate microshear bond strength of three bonding agents on wet enamel; and to compare microshear bond strength of three different bonding agents on dry and wet enamel. Sixty extracted noncarious human premolars were selected for this study. Flat enamel surfaces of approximately 3 mm were obtained by grinding the buccal surfaces of premolars with water-cooled diamond disks. This study evaluated one etch-and-rinse adhesive system (Single Bond 2) and two self-etching adhesive systems (Clearfil SE Bond and Xeno-V). The specimens were divided into two groups (n = 30). Group I (dry) was air-dried for 30 seconds and in group II (wet) surfaces were blotted with absorbent paper to remove excess water. These groups were further divided into six subgroups (n = 10) according to the adhesives used. The resin composite, Filtek Z 250, was bonded to flat enamel surfaces that had been treated with one of the adhesives, following the manufacturer's instructions. After being stored in water at 37°C for 24 hours, bonded specimens were stressed in universal testing machine (Fig. 3) at a crosshead speed of 1 mm/min. The data were evaluated with one-way and two-way analysis of variance (ANOVA), t-test, and Tukey's Multiple Post hoc tests (a = 0.05). The two-way ANOVA and Tukey's Multiple Post hoc tests showed significant differences among adhesive systems, but wetness did not influence microshear bond strength (p = 0.1762). The one-way ANOVA and t-test showed that the all-in-one adhesive (Xeno-V) was the only material influenced by the presence of water on the enamel surface. Xeno-V showed significantly higher microshear bond strength when the enamel was kept wet. Single Bond 2 adhesive showed significantly higher microshear bond strength as compared with Xeno-V adhesive but no

ON THE R-CURVE BEHAVIOR OF HUMAN TOOTH ENAMEL

OpenAIRE

Bajaj, Devendra; Arola, Dwayne

2009-01-01

In this study the crack growth resistance behavior and fracture toughness of human tooth enamel were quantified using incremental crack growth measures and conventional fracture mechanics. Results showed that enamel undergoes an increase in crack growth resistance (i.e. rising R-curve) with crack extension from the outer to the inner enamel, and that the rise in toughness is function of distance from the Dentin Enamel Junction (DEJ). The outer enamel exhibited the lowest apparent toughness (0...

Influence of Adhesives and Methods of Enamel Pretreatment on the Shear Bond Strength of Orthodontic Brackets.

Science.gov (United States)

Jurišić, Sanja; Jurišić, Gordan; Jurić, Hrvoje

2015-12-01

The objective of present study was to examine influence of adhesives and methods of enamel pretreatment on the shear bond strength (SBS) of orthodontic brackets. The adhesives used were resin-reinforced glass ionomer cements-GIC (Fuji Ortho LC) and composite resin (Transbond XT). The experimental sample consisted of 80 extracted human first premolars. The sample was divided into four equal groups, and the metal brackets were bonded with different enamel pretreatments by using two adhesives: group A-10% polyacrylic acid; Fuji Ortho LC, group B-37% phosphoric acid; Fuji Ortho LC, group C-self etching primer; Transbond XT, group D-37% phosphoric acid, primer; Transbond XT. SBS of brackets was measured. After debonding of brackets, the adhesive remnant index (ARI) was evaluated. After the statistical analysis of the collected data was performed (ANOVA; Sheffe post-hoc test), the results showed that significantly lower SBS of the group B was found in relation to the groups C (p=0.031) and D (p=0.026). The results of ARI were similar in all testing groups and it was not possible to determine any statistically significant difference of the ARI (Chi- square test) between all four experimental groups. The conclusion is that the use of composite resins material with appropriate enamel pretreatment according to manufacturer's recommendation is the "gold standard" for brackets bonding for fixed orthodontic appliances.

Influence of application method on surface free-energy and bond strength of universal adhesive systems to enamel.

Science.gov (United States)

Imai, Arisa; Takamizawa, Toshiki; Sai, Keiichi; Tsujimoto, Akimasa; Nojiri, Kie; Endo, Hajime; Barkmeier, Wayne W; Latta, Mark A; Miyazaki, Masashi

2017-10-01

The aim of the present study was to determine the influence of different adhesive application methods and etching modes on enamel bond effectiveness of universal adhesives using shear bond strength (SBS) testing and surface free-energy (SFE) measurements. The adhesives Scotchbond Universal, All-Bond Universal, Adhese Universal, and G-Premio Bond were used. Prepared bovine enamel specimens were divided into four groups, based on type of adhesive, and subjected to the following surface treatments: (i) total-etch mode with active application; (ii) total-etch mode with inactive application; (iii) self-etch mode with active application; and (iv) self-etch mode with inactive application. Bonded specimens were subjected to SBS testing. The SFE of the enamel surfaces with adhesive was measured after rinsing with acetone and water. The SBS values in total-etch mode were significantly higher than those in self-etch mode. In total-etch mode, significantly lower SBS values were observed with active application compared with inactive application; in contrast, in self-etch mode there were no significant differences in SBS between active and inactive applications. A reduction in total SFE was observed for active application compared with inactive application. The interaction between etching mode and application method was statistically significant, and the application method significantly affected enamel bond strength in total-etch mode. © 2017 Eur J Oral Sci.

Morphology of resin-dentin interfaces after Er,Cr:YSGG laser and acid etching preparation and application of different bonding systems.

Science.gov (United States)

Beer, Franziska; Buchmair, Alfred; Körpert, Wolfram; Marvastian, Leila; Wernisch, Johann; Moritz, Andreas

2012-07-01

The goal of this study was to show the modifications in the ultrastructure of the dentin surface morphology following different surface treatments. The stability of the adhesive compound with dentin after laser preparation compared with conventional preparation using different bonding agents was evaluated. An Er,Cr:YSGG laser and 36% phosphoric acid in combination with various bonding systems were used. A total of 100 caries-free human third molars were used in this study. Immediately after surgical removal teeth were cut using a band saw and 1-mm thick dentin slices were created starting at a distance of 4 mm from the cusp plane to ensure complete removal of the enamel. The discs were polished with silicon carbide paper into rectangular shapes to a size of 6 × 4 mm (±0,2 mm).The discs as well as the remaining teeth stumps were stored in 0.9% NaCl at room temperature. The specimens were divided into three main groups (group I laser group, group II etch group, group III laser and etch group) and each group was subdivided into three subgroups which were allocated to the different bonding systems (subgroup A Excite, subgroup B Scotchbond, subgroup C Syntac). Each disc and the corresponding tooth stump were treated in the same way. After preparation the bonding composite material was applied according to the manufacturers' guidelines in a hollow tube of 2 mm diameter to the disc as well as to the corresponding tooth stump. Shear bond strength testing and environmental scanning electron microscopy were used to assess the morphology and stability of the resin-dentin interface. The self-etching bonding system showed the highest and the most constant shear values in all three main groups, thus enabling etching with phosphoric acid after laser preparation to be avoided. Thus we conclude that laser preparation creates a surface texture that allows prediction of the quality of the restoration without the risk of negative influences during the following treatment steps. This

Indentation Damage and Crack Repair in Human Enamel*

Science.gov (United States)

Rivera, C.; Arola, D.; Ossa, A.

2013-01-01

Tooth enamel is the hardest and most highly mineralized tissue in the human body. While there have been a number of studies aimed at understanding the hardness and crack growth resistance behavior of this tissue, no study has evaluated if cracks in this tissue undergo repair. In this investigation the crack repair characteristics of young human enamel were evaluated as a function of patient gender and as a function of the distance from the Dentin Enamel Junction (DEJ). Cracks were introduced via microindentation along the prism direction and evaluated as a function of time after the indentation. Microscopic observations indicated that the repair of cracks began immediately after crack initiation and reaches saturation after approximately 48 hours. During this process he crack length decreased up to 10% of the initial length, and the largest degree of reduction occurred in the deep enamel, nearest the DEJ. In addition, it was found that the degree of repair was significantly greater in the enamel of female patients. PMID:23541701

Initial and long-term bond strengths of one-step self-etch adhesives with silane coupling agent to enamel-dentin-composite in combined situation.

Science.gov (United States)

Mamanee, Teerapong; Takahashi, Masahiro; Nakajima, Masatoshi; Foxton, Richard M; Tagami, Junji

2015-01-01

This study evaluated the effect of adding silane coupling agent on initial and long-term bond strengths of one-step self-etch adhesives to enamel-dentin-composite in combined situation. Cervical cavities were prepared on extracted molars and filled with Clearfil AP-X. After water-storage for one-week, the filled teeth were sectioned in halves to expose enamel, dentin and composite surfaces and then enamel-dentin-composite surface was totally applied with one of adhesive treatments (Clearfil SE One, Clearfil SE One with Clearfil Porcelain Bond Activator, Beautibond Multi, Beautibond Multi with Beautibond Multi PR Plus and Scotchbond Universal). After designed period, micro-shear bond strengths (µSBSs) to each substrate were determined. For each period of water-storage, additive silane treatments significantly increased µSBS to composite (penamel (p>0.05). Moreover, the stability of µSBS was depended on materials and substrates used.

Fracture Resistance of Lithium Disilicate Ceramics Bonded to Enamel or Dentin Using Different Resin Cement Types and Film Thicknesses.

Science.gov (United States)

Rojpaibool, Thitithorn; Leevailoj, Chalermpol

2017-02-01

To investigate the influence of cement film thickness, cement type, and substrate (enamel or dentin) on ceramic fracture resistance. One hundred extracted human third molars were polished to obtain 50 enamel and 50 dentin specimens. The specimens were cemented to 1-mm-thick lithium disilicate ceramic plates with different cement film thicknesses (100 and 300 μm) using metal strips as spacers. The cements used were etch-and-rinse (RelyX Ultimate) and self-adhesive (RelyX U200) resin cements. Compressive load was applied on the ceramic plates using a universal testing machine, and fracture loads were recorded in Newtons (N). Statistical analysis was performed by multiple regression (p enamel showed the highest mean fracture load (MFL; 1591 ± 172.59 N). The RelyX Ultimate groups MFLs were significantly higher than the corresponding RelyX U200 groups (p enamel (p enamel. Reduced resin film thickness could reduce lithium disilicate restoration fracture. Etch-and-rinse resin cements are recommended for cementing on either enamel or dentin, compared with self-adhesive resin cement, for improved fracture resistance. © 2015 by the American College of Prosthodontists.

Shear bond strength of two 2-step etch-and-rinse adhesives when bonding ceramic brackets to bovine enamel.

Science.gov (United States)

Godard, Marion; Deuve, Benjamin; Lopez, Isabelle; Hippolyte, Marie-Pascale; Barthélemi, Stéphane

2017-09-01

The present study assessed a fracture analysis and compared the shear bond strength (SBS) of two 2-step etch-and-rinse (E&R) adhesives when bonding ceramic orthodontic brackets to bovine enamel. Thirty healthy bovine mandibular incisors were selected and were equally and randomly assigned to 2 experimental groups. Ceramic brackets (FLI Signature Clear ® , RMO) were bonded onto bovine enamel using an adhesive system. In group 1 (n=15), the conventional E&R adhesive (OrthoSolo ® +Enlight ® , Ormco) was used, and in group 2 (n=15), the new E&R adhesive limited to ceramic bracket bonding (FLI ceramic adhesive ® : FLI sealant resin ® +FLI adhesive paste ® , RMO) was used. In order to obtain appropriate enamel surfaces, the vestibular surfaces of mandibular bovine incisors were flat ground. After bonding, all the samples were stored in distilled water at room temperature for 21 days and subsequently tested for SBS, using the Instron ® universal testing machine. The Adhesive Remnant Index (ARI) scores were evaluated. Failure modes were assessed using optical microscopy at magnification ×40. A statistic data analysis was performed using the Mann-Whitney U-test (Penamel/adhesive interface. A statistically significant difference was found for the ARI scores between the two groups (P=0.00996). Only two fractured brackets, which remained bonded onto the bovine enamel, were reported. Both occurred in group 1. When bonded to ceramic brackets, FLI ceramic adhesive ® (RMO) was demonstrated to be very predictable and safe for clinical application in enamel bonding, whereas the results obtained with the conventional adhesive system (OrthoSolo ® +Enlight ® , Ormco) were less reproducible and revealed slightly excessive shear bond strength values. Copyright © 2017 CEO. Published by Elsevier Masson SAS. All rights reserved.

Biofilm three-dimensional architecture influences in situ pH distribution pattern on the human enamel surface.

Science.gov (United States)

Xiao, Jin; Hara, Anderson T; Kim, Dongyeop; Zero, Domenick T; Koo, Hyun; Hwang, Geelsu

2017-06-01

To investigate how the biofilm three-dimensional (3D) architecture influences in situ pH distribution patterns on the enamel surface. Biofilms were formed on human tooth enamel in the presence of 1% sucrose or 0.5% glucose plus 0.5% fructose. At specific time points, biofilms were exposed to a neutral pH buffer to mimic the buffering of saliva and subsequently pulsed with 1% glucose to induce re-acidification. Simultaneous 3D pH mapping and architecture of intact biofilms was performed using two-photon confocal microscopy. The enamel surface and mineral content characteristics were examined successively via optical profilometry and microradiography analyses. Sucrose-mediated biofilm formation created spatial heterogeneities manifested by complex networks of bacterial clusters (microcolonies). Acidic regions (pHinterior of microcolonies, which impedes rapid neutralization (taking more than 120 min for neutralization). Glucose exposure rapidly re-created the acidic niches, indicating formation of diffusion barriers associated with microcolonies structure. Enamel demineralization (white spots), rougher surface, deeper lesion and more mineral loss appeared to be associated with the localization of these bacterial clusters at the biofilm-enamel interface. Similar 3D architecture was observed in plaque-biofilms formed in vivo in the presence of sucrose. The formation of complex 3D architectures creates spatially heterogeneous acidic microenvironments in close proximity of enamel surface, which might correlate with the localized pattern of the onset of carious lesions (white spot like) on teeth.

The molecular basis of hereditary enamel defects in humans.

Science.gov (United States)

Wright, J T; Carrion, I A; Morris, C

2015-01-01

The formation of human enamel is highly regulated at the molecular level and involves thousands of genes. Requisites for development of this highly mineralized tissue include cell differentiation; production of a unique extracellular matrix; processing of the extracellular matrix; altering of cell function during different stages of enamel formation; cell movement and attachment; regulation of ion and protein movement; and regulation of hydration, pH, and other conditions of the microenvironment, to name just a few. Not surprising, there is a plethora of hereditary conditions with an enamel phenotype. The objective of this review was to identify the hereditary conditions listed on Online Mendelian Inheritance in Man (OMIM) that have an associated enamel phenotype and whether a causative gene has been identified. The OMIM database was searched with the terms amelogenesis, enamel, dental, and tooth, and all results were screened by 2 individuals to determine if an enamel phenotype was identified. Gene and gene product function was reviewed on OMIM and from publications identified in PubMed. The search strategy revealed 91 conditions listed in OMIM as having an enamel phenotype, and of those, 71 have a known molecular etiology or linked genetic loci. The purported protein function of those conditions with a known genetic basis included enzymes, regulatory proteins, extracellular matrix proteins, transcription factors, and transmembrane proteins. The most common enamel phenotype was a deficient amount of enamel, or enamel hypoplasia, with hypomineralization defects being reported less frequently. Knowing these molecular defects allows an initial cataloging of molecular pathways that lead to hereditary enamel defects in humans. This knowledge provides insight into the diverse molecular pathways involved in enamel formation and can be useful when searching for the genetic etiology of hereditary conditions that involve enamel. © International & American Associations for

The Molecular Basis of Hereditary Enamel Defects in Humans

Science.gov (United States)

Carrion, I.A.; Morris, C.

2015-01-01

The formation of human enamel is highly regulated at the molecular level and involves thousands of genes. Requisites for development of this highly mineralized tissue include cell differentiation; production of a unique extracellular matrix; processing of the extracellular matrix; altering of cell function during different stages of enamel formation; cell movement and attachment; regulation of ion and protein movement; and regulation of hydration, pH, and other conditions of the microenvironment, to name just a few. Not surprising, there is a plethora of hereditary conditions with an enamel phenotype. The objective of this review was to identify the hereditary conditions listed on Online Mendelian Inheritance in Man (OMIM) that have an associated enamel phenotype and whether a causative gene has been identified. The OMIM database was searched with the terms amelogenesis, enamel, dental, and tooth, and all results were screened by 2 individuals to determine if an enamel phenotype was identified. Gene and gene product function was reviewed on OMIM and from publications identified in PubMed. The search strategy revealed 91 conditions listed in OMIM as having an enamel phenotype, and of those, 71 have a known molecular etiology or linked genetic loci. The purported protein function of those conditions with a known genetic basis included enzymes, regulatory proteins, extracellular matrix proteins, transcription factors, and transmembrane proteins. The most common enamel phenotype was a deficient amount of enamel, or enamel hypoplasia, with hypomineralization defects being reported less frequently. Knowing these molecular defects allows an initial cataloging of molecular pathways that lead to hereditary enamel defects in humans. This knowledge provides insight into the diverse molecular pathways involved in enamel formation and can be useful when searching for the genetic etiology of hereditary conditions that involve enamel. PMID:25389004

Morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel.

Science.gov (United States)

Manuela Díaz-Monroy, Jennifer; Contreras-Bulnes, Rosalía; Fernando Olea-Mejía, Oscar; Emma Rodríguez-Vilchis, Laura; Sanchez-Flores, Ignacio

2014-06-01

Several scientific reports have shown the effects of Er:YAG laser irradiation on enamel morphology. However, there is lack of information regarding the morphological alterations produced by the acid attack on the irradiated surfaces. The aim of this study was to evaluate the morphological changes produced by acid dissolution in Er:YAG laser irradiated dental enamel. Forty-eight enamel samples were divided into four groups (n = 12). GI (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm(2) ), 200 mJ (25.5 J/cm(2) ), and 300 mJ (38.2 J/cm(2) ), respectively, at 10 Hz without water irrigation. Enamel morphology was evaluated before-irradiation, after-irradiation, and after-acid dissolution, by scanning electron microscopy (SEM). Sample coating was avoided and SEM analysis was performed in a low-vacuum mode. To facilitate the location of the assessment area, a reference point was marked. Morphological changes produced by acid dissolution of irradiated enamel were observed, specifically on laser-induced undesired effects. These morphological changes were from mild to severe, depending on the presence of after-irradiation undesired effects. © 2014 Wiley Periodicals, Inc.

Indentation damage and crack repair in human enamel.

Science.gov (United States)

Rivera, C; Arola, D; Ossa, A

2013-05-01

Tooth enamel is the hardest and most highly mineralized tissue in the human body. While there have been a number of studies aimed at understanding the hardness and crack growth resistance behavior of this tissue, no study has evaluated if cracks in this tissue undergo repair. In this investigation the crack repair characteristics of young human enamel were evaluated as a function of patient gender and as a function of the distance from the Dentin Enamel Junction (DEJ). Cracks were introduced via microindentation along the prism direction and evaluated as a function of time after the indentation. Microscopic observations indicated that the repair of cracks began immediately after crack initiation and reaches saturation after approximately 48 h. During this process he crack length decreased up to 10% of the initial length, and the largest degree of reduction occurred in the deep enamel, nearest the DEJ. In addition, it was found that the degree of repair was significantly greater in the enamel of female patients. Copyright © 2013 Elsevier Ltd. All rights reserved.

Marginal microleakage of resin-modified glass-ionomer and composite resin restorations: Effect of using etch-and-rinse and self-etch adhesives

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Maryam Khoroushi

2012-01-01

Full Text Available Objectives: Previous studies have shown that dental adhesives increase the bond strength of resin-modified glass-ionomer (RMGI restorative materials to dentin. This in vitro study has evaluated the effect of etch-and-rinse and self-etch bonding systems v/s cavity conditioner, and in comparison to similar composite resin restorations on maintaining the marginal sealing of RMGI restorations. Materials and Methods: 98 rectangular cavities (2.5×3×1.5 mm were prepared on buccal and palatal aspects of 49 human maxillary premolars, randomly divided into 7 groups (N=14. The cavities in groups 1, 2 and 3 were restored using a composite resin (APX. The cavities in groups 4, 5, 6 and 7 were restored using a resin-modified glass-ionomer (Fuji II LC. Before restoring, adhesive systems (Optibond FL = OFL, three-step etch-and-rinse; One Step Plus = OSP, two-step etch-and-rinse; Clearfil Protect Bond = CPB, two-step self-etch were used as bonding agents in groups 1-6 as follow: OFL in groups 1 and 4, OSP in groups 2 and 5, and CPB in groups 3 and 6, respectively. The specimens in group 7 were restored with GC cavity conditioner and Fuji II LC. All the specimens were thermo-cycled for 1000 cycles. Microleakage scores were determined using dye penetration method. Statistical analyzes were carried out with Kruskal-Wallis and Mann-Whitney U tests (α=0.05. Results: There were significant differences in microleakage scores at both enamel and dentinal margins between the study groups (P<0.05. The lowest microleakage scores at enamel and dentin margins of RMGI restorations were observed in group 6. Conclusion: Use of two-step self-etch adhesive, prior to restoring cervical cavities with RMGIC, seems to be more efficacious than the conventional cavity conditioner in decreasing marginal microleakage.

Retrospective dosimetry assessment using the 380 deg. C thermoluminescence peak of tooth enamel

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Secu, C.E. [National Institute for Materials Physics, PO Box MG-7, 77125 Bucharest-Magurele (Romania); Cherestes, M. [Dozimed Ltd., Dosimetry Laboratory, 77125 Bucharest-Magurele (Romania); Secu, M., E-mail: msecu@infim.ro [National Institute for Materials Physics, PO Box MG-7, 77125 Bucharest-Magurele (Romania); Cherestes, C.; Paraschiva, V. [Dozimed Ltd., Dosimetry Laboratory, 77125 Bucharest-Magurele (Romania); Barca, C. [Faculty of Physics, University of Bucharest, 77125 Bucharest-Magurele (Romania)

2011-10-15

The thermoluminescence (TL) response to gamma-ray irradiation of tooth enamel is reported. The tooth enamel was separated from dentine by using mechanical and physico-chemical procedures followed by grinding (grain size {approx}100 {mu}m) and etching. The TL was attributed to the recombination of CO{sub 2}{sup -} radicals incorporated into or attached to the surface of hydroxyapatite crystals. The growth of the {approx}380 deg. C TL peak with absorbed dose was examined with irradiated tooth enamel samples and reconstructed doses evaluated for tooth enamel samples from four human subjects. - Highlights: > Thermoluminescence response after gamma-ray irradiation of tooth enamel was investigated. > Thermoluminescence was attributed to the recombination of CO{sub 2}{sup -} radicals. > CO{sub 2}{sup -} radicals are produced inside or at the surface of hydroxyapatite crystals. > From the growth of the 380C peak reconstructed doses have been evaluated.

Morphology and structure of polymer layers protecting dental enamel against erosion.

Science.gov (United States)

Beyer, Markus; Reichert, Jörg; Sigusch, Bernd W; Watts, David C; Jandt, Klaus D

2012-10-01

Human dental erosion caused by acids is a major factor for tooth decay. Adding polymers to acidic soft drinks is one important approach to reduce human dental erosion caused by acids. The aim of this study was to investigate the thickness and the structure of polymer layers adsorbed in vitro on human dental enamel from polymer modified citric acid solutions. The polymers propylene glycol alginate (PGA), highly esterified pectin (HP) and gum arabic (GA) were used to prepare polymer modified citric acids solutions (PMCAS, pH 3.3). With these PMCAS, enamel samples were treated for 30, 60 and 120s respectively to deposit polymer layers on the enamel surface. Profilometer scratches on the enamel surface were used to estimate the thickness of the polymer layers via atomic force microscopy (AFM). The composition of the deposited polymer layers was investigated with X-ray photoelectron spectroscopy (XPS). In addition the polymer-enamel interaction was investigated with zeta-potential measurements and scanning electron microscopy (SEM). It has been shown that the profilometer scratch depth on the enamel with deposited polymers was in the range of 10nm (30s treatment time) up to 25nm (120s treatment time). Compared to this, the unmodified CAS-treated surface showed a greater scratch depth: from nearly 30nm (30s treatment time) up to 60nm (120s treatment time). Based on XPS measurements, scanning electron microscopy (SEM) and zeta-potential measurements, a model was hypothesized which describes the layer deposited on the enamel surface as consisting of two opposing gradients of polymer molecules and hydroxyapatite (HA) particles. In this study, the structure and composition of polymer layers deposited on in vitro dental enamel during treatment with polymer modified citric acid solutions were investigated. Observations are consistent with a layer consisting of two opposing gradients of hydroxyapatite particles and polymer molecules. This leads to reduced erosive effects of

Synthetic tooth enamel: SEM characterization of a fluoride hydroxyapatite coating for dentistry applications

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Marise Oliveira

2007-06-01

Full Text Available An alternative to etching enamel for retention of an adhesive is to grow crystals on the enamel surface. The potential advantages of crystal growth include easy procedure and less damage to the enamel. These crystals retain the adhesive or are the actual dental restoration. In this work, a paste of synthetic enamel was used to grow crystals of fluoride hydroxyapatite (F-HA onto the human tooth surface. This technique can be used for several dentistry applications like enamel whitening, strengthening and restoration of early carie lesions. The low cost of reagents and simplicity of the technique along with the biocompatibility of the paste render possible the utilization on the market. The samples were prepared through the application of the paste by the incremental technique. The results obtained by scanning electron microscope (SEM/EDX have indicated the deposition of a homogeneous layer of calcium phosphate that was grown onto the enamel substrate. The average thickness of the deposited film was in the range of 50-100 µm and with a similar density from the natural enamel observed by radiographic images.

Influence of warm air-drying on enamel bond strength and surface free-energy of self-etch adhesives.

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Shiratsuchi, Koji; Tsujimoto, Akimasa; Takamizawa, Toshiki; Furuichi, Tetsuya; Tsubota, Keishi; Kurokawa, Hiroyasu; Miyazaki, Masashi

2013-08-01

We examined the effect of warm air-drying on the enamel bond strengths and the surface free-energy of three single-step self-etch adhesives. Bovine mandibular incisors were mounted in self-curing resin and then wet ground with #600 silicon carbide (SiC) paper. The adhesives were applied according to the instructions of the respective manufacturers and then dried in a stream of normal (23°C) or warm (37°C) air for 5, 10, and 20 s. After visible-light irradiation of the adhesives, resin composites were condensed into a mold and polymerized. Ten samples per test group were stored in distilled water at 37°C for 24 h and then the bond strengths were measured. The surface free-energies were determined by measuring the contact angles of three test liquids placed on the cured adhesives. The enamel bond strengths varied according to the air-drying time and ranged from 15.8 to 19.1 MPa. The trends for the bond strengths were different among the materials. The value of the γS⁺ component increased slightly when drying was performed with a stream of warm air, whereas that of the γS⁻ component decreased significantly. These data suggest that warm air-drying is essential to obtain adequate enamel bond strengths, although increasing the drying time did not significantly influence the bond strength. © 2013 Eur J Oral Sci.

Effect of a low-viscosity adhesive resin on the adhesion of metal brackets to enamel etched with hydrochloric or phosphoric acid combined with conventional adhesives.

Science.gov (United States)

Yetkiner, Enver; Ozcan, Mutlu; Wegehaupt, Florian Just; Wiegand, Annette; Eden, Ece; Attin, Thomas

2013-12-01

This study investigated the effect of a low-viscosity adhesive resin (Icon) applied after either hydrochloric (HCl) or phosphoric acid (H3PO4) on the adhesion of metal brackets to enamel. Failure types were analyzed. The crowns of bovine incisors (N = 20) were sectioned mesio-distally and inciso-gingivally, then randomly assigned to 4 groups according to the following protocols to receive mandibular incisor brackets: 1) H3PO4 (37%)+TransbondXT (3M UNITEK); 2) H3PO4 (37%)+Icon+TransbondXT; 3) HCl (15%)+Icon (DMG)+TransbondXT 4) HCl (15%)+Icon+Heliobond (Ivoclar Vivadent)+TransbondXT. Specimens were stored in distilled water at 37°C for 24 h and thermocycled (5000x, 5°C to 55°C). The shear bond strength (SBS) test was performed using a universal testing machine (1 mm/min). Failure types were classified according to the Adhesive Remnant Index (ARI). Contact angles of adhesive resins were measured (n = 5 per adhesive) on ceramic surfaces. No significant difference in SBS was observed, implying no difference between combinations of adhesive resins and etching agents (p = 0.712; ANOVA). The Weibull distribution presented significantly lower Weibull modulus (m) of group 3 (m = 2.97) compared to other groups (m = 5.2 to 6.6) (p group 1 (45.4 ± 7.9) > group 2 (44.2 ± 10.6) > group 3 (42.6 ± 15.5). While in groups 1, 3, and 4 exclusively an ARI score of 0 (no adhesive left on tooth) was observed, in group 2, only one specimen demonstrated score 1 (less than half of adhesive left on tooth). Contact angle measurements were as follows: Icon (25.86 ± 3.81 degrees), Heliobond (31.98 ± 3.17 degrees), TransbondXT (35 ± 2.21 degrees). Icon can be safely used with the conventional adhesives tested on surfaces etched with either HCl or H3PO4.

Shear bond strength of self-etching adhesive systems with different pH values to bleached and/or CPP-ACP-treated enamel.

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Oskoee, Siavash Savadi; Bahari, Mahmoud; Kimyai, Soodabeh; Navimipour, Elmira Jafari; Firouzmandi, Maryam

2012-08-01

To compare shear bond strengths of three different self-etching adhesive systems of different pH values to enamel bleached with carbamide peroxide, treated with casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), or treated with CPP-ACP subsequent to bleaching with carbamide peroxide. Thirty-six human third molars were cut into 4 sections and randomly assigned to 4 groups (n = 36): group I: no treatment; group II: bleaching; group III: CPP-ACP; group IV: bleaching and CPP-ACP. After surface treatments, the samples of each group were further divided into three subgroups (n = 12) based on the adhesive used. The adhesives Clearfil SE Bond (CSE), AdhesE (ADE), and Adper SE Plus (ADP) were applied, and resin composite cylinders with a diameter of 2 mm and a height of 4 mm were bonded to the enamel. Then the specimens were subjected to shear bond strength testing. Two-way ANOVA and a post-hoc Tukey's test were used for statistical analysis (α = 0.05). There were significant differences between the adhesive systems (p system showed the highest bond strength, and the bleaching procedure reduced bond strengths (p = 0.001). Furthermore, there were no significant differences in shear bond strength values between the control and CPP groups. However, the differences between other groups were statistically significant (p material dependent.

CORROSION IN ACIDIC BEVERAGES AND RECOVERY OF MICROHARDNESS OF HUMAN TEETH ENAMEL

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Petra Gaalova

2016-05-01

Full Text Available We studied the influence of corrosion in acidic beverages (white wine, pH~3.5 on micromechanical properties of human teeth. Simultaneously, the effect of fluorine-containing mouthwash (pH~4.4 and of artificial saliva (pH~5.3 in terms of their protective action against corrosion, and the recovery of mechanical properties through fluoridation and re-calcification was studied. The influence of the solutions on Vickers hardness of dental enamel was monitored on the basis of results from the corrosion tests carried out under quasi-dynamic conditions. The tests were performed at the temperature corresponding to the temperature of human body (37°C. The measurements confirmed a significant deterioration of microhardness with prolonged exposure to white wine. The Vickers hardness decreased from 347 HV0.2 in un-corroded specimens to 186 HV0.2 in samples corroded for 60 minutes in white wine. A recovery of Vickers hardness was observed after 60 minutes exposition time in the fluoridation solution, with the increase from 186 to 372 HV0.2. Similar effect was observed in the artificial saliva solution, with observed hardness increase from 186 to 320 HV0.2. Healing of corrosion-induced defects by the action of both solutions was observed by SEM, and associated with observed increase of hardness

[Bonding strength of resin and tooth enamel after teeth bleaching with cold plasma].

Science.gov (United States)

Zhu, Meng-meng; Wang, Guo-min; Sun, Ke; Li, Ying-long; Pan, Jie

2016-02-18

To investigate the immediate bond strength and surface structure of resin and the tooth enamel which treated by cold plasma. In the study, 40 bovine incisors were divided into two equal parts. In this sense, all enamel adhesive samples were prepared and then randomly divided into 4 groups (n =20). group 1: acid + single bond 2+resin composite (control group); group 2:beyond bleaching+ acid+single bond 2+resin composite; group 3: treated by cold plasma for 5 minutes+ acid+single bond 2+resin composite; group 4: treated by cold plasma for 5 minutes+single bond 2+resin composite. Single bond 2 bonding system and Filtek Z250 resin were used in this experiment. The shear bond strength was tested by universal testing machine. The surface of the enamel in different processes was observed by scanning electron microscope (SEM). Statistical analyses by the single factor analysis of variance and multiple pairwise comparisons were performed with SPSS 17.0 . The shear bond strength of group 4 (8.60 MPa) was significantly lower than that of the other three groups (Penamel treated by cold plasma had slight molten form, which was different from etched enamel surface.The fractured surface of group 3 was mix fracture, which was similar to the control group (group 1). Compared with the conventional clinic bleaching, immediate bond strength of resin-enamel that treated by cold plasma has not been affected.

Effect of different methods of enamel conditioning on bond strength of orthodontic brackets

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Davari AR

2007-01-01

Full Text Available Background and Aim: With the introduction of different bondable restorative materials in dentistry, various methods have been suggested to enhance the polymerization and shear bond strength of these materials. The aim of this study was to determine the effects of different methods of enamel conditioning on bond strength of orthodontic brackets and on the bracket/ adhesive failure mode. Materials and Methods: In this experimental in vitro study, brackets were bonded to thirty-six bovine incisor teeth with different protocols according to the manufacturer's instructions as follows: Group 1: conventional multistep adhesive (n=12; Group 2: self-etching primer system (n=12; Group 3: acid+self-etching primer system (n=12. Specimens were loaded in a universal testing machine (Instron, Canton and Mass and the mode of failure was recorded. Data were analyzed by ANOVA and Kruskall-Wallis tests with p<0.05 as the limit of significance. Results: The mean shear bond strength was 11.7 ± 4.2, 10.5 ± 4.4, and 10.9 ± 4.8 MPa for group 1, 2, and 3 respectively. There was no significant difference in bond strength among the three groups (P=0.800. No significant difference was observed among the three groups with respect to residual adhesive on the enamel surfaces (P=0.554. Conclusion: Based on the results of the present study, the use of self-etching primers may be an alternative to conventional phosphoric acid pre-treatment in orthodontic bonding.

Near-surface structural examination of human tooth enamel subject to in vitro demineralization and remineralization

Science.gov (United States)

Gaines, Carmen Veronica

The early stages of chemical tooth decay are governed by dynamic processes of demineralization and remineralization of dental enamel that initiates along the surface of the tooth. Conventional diagnostic techniques lack the spatial resolution required to analyze near-surface structural changes in enamel at the submicron level. In this study, slabs of highly-polished, decay-free human enamel were subjected to 0.12M EDTA and buffered lactic acid demineralizing agents and MI Paste(TM) and calcifying (0.1 ppm F) remineralizing treatments in vitro. Grazing incidence x-ray diffraction (GIXD), a technique typically used for thin film analysis, provided depth profiles of crystallinity changes in surface enamel with a resolution better than 100 nm. In conjunction with nanoindentation, a technique gaining acceptance as a means of examining the mechanical properties of sound enamel, these results were corroborated with well-established microscopy and Raman techniques to assess the nanohardness, morphologies and chemical nature of treated enamel. Interestingly, the average crystallite size of surface enamel along its c-axis dimension increased by nearly 40% after a 60 min EDTA treatment as detected by GIXD. This result was in direct contrast to the obvious surface degradation observed by microscopic and confocal Raman imaging. A decrease in nanohardness from 4.86 +/- 0.44 GPa to 0.28 +/- 0.10 GPa was observed. Collective results suggest that mineral dissolution characteristics evident on the micron scale may not be fully translated to the nanoscale in assessing the integrity of chemically-modified tooth enamel. While an intuitive decrease in enamel crystallinity was observed with buffered lactic acid-treated samples, demineralization was too slow to adequately quantify the enamel property changes seen. MI Paste(TM) treatment of EDTA-demineralized enamel showed preferential growth along the a-axis direction. Calcifying solution treatments of both demineralized sample types

Trace Elements in Human Tooth Enamel

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Nixon, G. S. [Turner Dental School, University Of Manchester, Manchester (United Kingdom); Smith, H.; Livingston, H. D. [Department of Forensic Medicine, University Of Glasgow, Glasgow (United Kingdom)

1967-10-15

The trace elements are considered to play a role in the resistance of teeth to dental caries. The exact mechanism by which they act has not yet been fully established. Estimations of trace elements have been undertaken in sound human teeth. By means of activation analysis it has been possible to determine trace element concentrations in different layers of enamel in the same tooth. The concentrations of the following elements have been determined: arsenic, antimony, copper, zinc, manganese, mercury, molybdenum and vanadium. The distribution of trace elements in enamel varies from those with a narrow range, such as manganese, to those with a broad range, such as antimony. The elements present in the broad range are considered to be non-essential and their presence is thought to result from a chance incorporation into the enamel. Those in the narrow range appear to be essential trace elements and are present in amounts which do not vary unduly from other body tissues. Only manganese and zinc were found in higher concentrations in the surface layer of enamel compared with the inner layers. The importance of the concentration of trace elements on this surface layer of enamel is emphasized as this layer is the site of the first attack by the carious process. (author)

Novel Dental Cement to Combat Biofilms and Reduce Acids for Orthodontic Applications to Avoid Enamel Demineralization

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Ning Zhang

2016-05-01

Full Text Available Orthodontic treatments often lead to biofilm buildup and white spot lesions due to enamel demineralization. The objectives of this study were to develop a novel bioactive orthodontic cement to prevent white spot lesions, and to determine the effects of cement compositions on biofilm growth and acid production. 2-methacryloyloxyethyl phosphorylcholine (MPC, nanoparticles of silver (NAg, and dimethylaminohexadecyl methacrylate (DMAHDM were incorporated into a resin-modified glass ionomer cement (RMGI. Enamel shear bond strength (SBS was determined. Protein adsorption was determined using a micro bicinchoninic acid method. A dental plaque microcosm biofilm model with human saliva as inoculum was used to investigate metabolic activity, colony-forming units (CFU and lactic acid production. Incorporating 3% of MPC, 1.5% of DMAHDM, and 0.1% of NAg into RMGI, and immersing in distilled water at 37 °C for 30 days, did not decrease the SBS, compared to control (p > 0.1. RMGI with 3% MPC + 1.5% DMAHDM + 0.1% NAg had protein amount that was 1/10 that of control. RMGI with triple agents (MPC + DMAHDM + NAg had much stronger antibacterial property than using a single agent or double agents (p < 0.05. Biofilm CFU on RMGI with triple agents was reduced by more than 3 orders of magnitude, compared to commercial control. Biofilm metabolic activity and acid production were also greatly reduced. In conclusion, adding MPC + DMAHDM + NAg in RMGI substantially inhibited biofilm viability and acid production, without compromising the orthodontic bracket bond strength to enamel. The novel bioactive cement is promising for orthodontic applications to hinder biofilms and plaque buildup and enamel demineralization.

The effect of theobromine 200 mg/l topical gel exposure duration against surface enamel hardness resistance from 1% citric acid

Science.gov (United States)

Herisa, H. M.; Noerdin, A.; Eriwati, Y. K.

2017-08-01

Theobromine can be used to prevent the demineralization of enamel and can stimulate the growth of new enamels. This study analyzes the effect of theobromine’s gel duration exposure on enamel hardness resistance from 1% citric acid. Twenty-eight specimens were divided into three experimental groups; were exposed to theobromine gel 200 mg/l for 16, 48, and 96 minutes; and were then immersed in 1% citric acid. The control group was only immersed in 1% citric acid. Results: A Wilcoxon test showed a significant increase and decrease in enamel microhardness after exposure to theobromine gel and citric acid (p enamel microhardness between different durations of exposure to theobromine gel and immersion in citric acid (p enamel microhardness but did not contribute to the enamel’s hardness resistance after immersion in 1% citric acid. The duration of theobromine gel application affected enamel microhardness and acid resistance.

Impact of laminar flow velocity of different acids on enamel calcium loss.

Science.gov (United States)

Attin, T; Becker, K; Wiegand, A; Tauböck, T T; Wegehaupt, F J

2013-03-01

The aim of the study was to evaluate the impact of flow velocity under laminar flow conditions of different acidic solutions on enamel erosion. A total of 240 bovine enamel specimens were prepared and allocated to 30 groups (n = 8 each). Samples of 18 groups were superfused in a flow chamber system with laminar flow behavior using 1 ml of citric acid or hydrochloric acid (HCl) of pH 2.0, 2.6 or 3.0. Flow rates in the sample chamber were adjusted to 10, 60 or 100 μl/min. To simulate turbulent flow behavior, samples of six groups were immersed in 1 ml of the respective solution, which was vortexed (15 min, 600 rpm). For simulating non-agitated conditions, specimens of the remaining six groups were immersed in 1 ml of the respective solution without stirring. Calcium in the solutions, released from the enamel samples, was determined using Arsenazo III method. For acidic solutions of pH 2.6 and 3.0, erosive potential of citric acid was equivalent to that of HCl at a flow of 100 μl/min. The same observation was made for the samples subjected to turbulent conditions at pH 3. At all other conditions, citric acid induced a significantly higher calcium loss than HCl. It is concluded that under slow laminar flow conditions, flow rate variations lead to higher erosive impact of citric acid compared to hydrochloric acid at pH 2.0, but not at pH ≥ 2.6 and increasing laminar flow or turbulent conditions. Erosive enamel dissolution under laminar flow conditions is a complex issue influenced by flow rate and acidic substrate.

Marginal microleakage in vitro study of occlusal fissures sealing prepared and etched or not with Er: YAG laser

International Nuclear Information System (INIS)

Youssef, Fernanda de Almeida

2004-01-01

The aim of this in vitro study was to evaluate the degree of marginal microleakage in occlusal sealing by invasive techniques, after preparation with Er:YAG laser followed or not by Er:YAG laser etching and compared to the conventional technique. Thirty human premolars were divided into three groups: A (control group) - cavities were prepared with high speed and etched with 37% orthophosphoric acid; group B - cavities were prepared with Er:YAG (350 mJ, 4 Hz and 112 J /cm 2 ) and etched with 37% orthophosphoric acid; group C - cavities were prepared with Er:YAG laser (350 mJ, 4 Hz and 112 J/cm 2 ), and etched with Er:YAG laser (80 mJ, 4 Hz and 25 m/cm 2 ). All cavities were treated with the same adhesive system and restored with flow composite according to manufacturer instructions. Teeth were submitted to thermal cycling procedures and immersed in 50% Silver Nitrate Solutions for 8 hours in total darkness. Teeth were sectioned longitudinally in the bucco-lingual direction, in slices of 1 mm thick. Each slice was immersed into photo developing solution under 16 hours of fluorescent light. Slices were photographed and microleakage was scored from 0 to 7 J by three standard examiners. Results showed statistically significant differences for group C (Er:YAG laser preparation and etching). We concluded that Er:YAG laser can be used for cavity preparation of occlusal sealing, like the conventional high speed method. However, this laser, used as enamel etching agent, could not promote an adequate surface for adhesive procedures. (author)

Wettability modification of human tooth surface by water and UV and electron-beam radiation

International Nuclear Information System (INIS)

Tiznado-Orozco, Gaby E.; Reyes-Gasga, José; Elefterie, Florina; Beyens, Christophe; Maschke, Ulrich; Brès, Etienne F.

2015-01-01

The wettability of the human tooth enamel and dentin was analyzed by measuring the contact angles of a drop of distilled water deposited on the surface. The samples were cut along the transverse and longitudinal directions, and their surfaces were subjected to metallographic mirror-finish polishing. Some samples were also acid etched until their microstructure became exposed. Wettability measurements of the samples were done in dry and wet conditions and after ultraviolet (UV) and electron beam (EB) irradiations. The results indicate that water by itself was able to increase the hydrophobicity of these materials. The UV irradiation momentarily reduced the contact angle values, but they recovered after a short time. EB irradiation raised the contact angle and maintained it for a long time. Both enamel and dentin surfaces showed a wide range of contact angles, from approximately 10° (hydrophilic) to 90° (hydrophobic), although the contact angle showed more variability on enamel than on dentin surfaces. Whether the sample's surface had been polished or etched did not influence the contact angle value in wet conditions. - Highlights: • Human tooth surface wettability changes in dry/wet and UV/EB radiation conditions. • More variability in contact angle is observed on enamel than on dentin surfaces. • Water by itself increases the hydrophobicity of the human tooth surface. • UV irradiation reduces momentarily the human tooth surface hydrophobicity. • EB irradiation increases and maintains the hydrophobicity for a long time

Wettability modification of human tooth surface by water and UV and electron-beam radiation

Energy Technology Data Exchange (ETDEWEB)

Tiznado-Orozco, Gaby E., E-mail: gab0409@gmail.com [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Unidad Académica de Odontología, Universidad Autónoma de Nayarit, Edificio E7, Ciudad de la Cultura “Amado Nervo”, C.P. 63190 Tepic, Nayarit (Mexico); Reyes-Gasga, José, E-mail: jreyes@fisica.unam.mx [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Instituto de Física, UNAM, Circuito de la Investigación s/n, Ciudad Universitaria, 04510 Coyoacan, México, D.F. (Mexico); Elefterie, Florina, E-mail: elefterie_florina@yahoo.com [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Beyens, Christophe, E-mail: christophe.beyens@ed.univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Maschke, Ulrich, E-mail: Ulrich.Maschke@univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France); Brès, Etienne F., E-mail: etienne.bres@univ-lille1.fr [UMET, Bâtiment C6, Université de Lille 1, Sciences et Technologies, 59650 Villeneuve d' Ascq (France)

2015-12-01

The wettability of the human tooth enamel and dentin was analyzed by measuring the contact angles of a drop of distilled water deposited on the surface. The samples were cut along the transverse and longitudinal directions, and their surfaces were subjected to metallographic mirror-finish polishing. Some samples were also acid etched until their microstructure became exposed. Wettability measurements of the samples were done in dry and wet conditions and after ultraviolet (UV) and electron beam (EB) irradiations. The results indicate that water by itself was able to increase the hydrophobicity of these materials. The UV irradiation momentarily reduced the contact angle values, but they recovered after a short time. EB irradiation raised the contact angle and maintained it for a long time. Both enamel and dentin surfaces showed a wide range of contact angles, from approximately 10° (hydrophilic) to 90° (hydrophobic), although the contact angle showed more variability on enamel than on dentin surfaces. Whether the sample's surface had been polished or etched did not influence the contact angle value in wet conditions. - Highlights: • Human tooth surface wettability changes in dry/wet and UV/EB radiation conditions. • More variability in contact angle is observed on enamel than on dentin surfaces. • Water by itself increases the hydrophobicity of the human tooth surface. • UV irradiation reduces momentarily the human tooth surface hydrophobicity. • EB irradiation increases and maintains the hydrophobicity for a long time.

The effect of various adhesives, enamel etching, and base treatment on the failure frequency of customized lingual brackets: a randomized clinical trial.

Science.gov (United States)

Mavreas, Dimitrios; Cuzin, Jean-François; Boonen, Guillaume; Vande Vannet, Bart

2018-05-25

The aim of this paper was to compare failure differences in precious metal customized lingual brackets bonded with three adhesive systems. Also, differences in failure of non-precious metal brackets with and without a silicatized base layer bonded with the same adhesive, as well as the influence of enamel etching prior to using a self-etching dual cure resin were explored. Five different groups were defined in a semi-randomized approach. Group 1 (IME): Maxcem Elite with 378 Incognito brackets and etched teeth, Group 2 (IMNE): Maxcem Elite with 193 Incognito brackets on non-etched teeth, Group 3 (INE): Nexus+Excite with 385 Incognito brackets, Group 4 (IRE): Relyx with 162 Incognito brackets, Group 5 (HRME) and Group 6 (HNRME): Maxcem Elite with 182 Harmony brackets with silicatized and non-slicatized bases respectively. Bracket failures were recorded over a 12-month period. The number of failures during the observation period was small in the various adhesives types of groups, as well as in HRME and HNRME groups, and the comparisons among those groups were non-significant (P > 0.05). A statistically significant difference (P brackets failure frequencies (rates) are not different for the three adhesive materials tested. 2. Eliminating the etching stage when using self-etch/self-adhesive adhesives, may lead to a dramatic increase in the failure rates. 3. Silicoating of stainless steel customized lingual brackets does not seem to influence the failure of the bonds.

Three-dimensional quantitative analysis of adhesive remnants and enamel loss resulting from debonding orthodontic molar tubes

OpenAIRE

Janiszewska-Olszowska, Joanna; Tandecka, Katarzyna; Szatkiewicz, Tomasz; Sporniak-Tutak, Katarzyna; Grocholewicz, Katarzyna

2014-01-01

Aims Presenting a new method for direct, quantitative analysis of enamel surface. Measurement of adhesive remnants and enamel loss resulting from debonding molar tubes. Material and methods Buccal surfaces of fifteen extracted human molars were directly scanned with an optic blue-light 3D scanner to the nearest 2 μm. After 20 s etching molar tubes were bonded and after 24 h storing in 0.9% saline - debonded. Then 3D scanning was repeated. Superimposition and comparison were proceeded and shap...

Micro-indentation fracture behavior of human enamel.

Science.gov (United States)

Padmanabhan, Sanosh Kunjalukkal; Balakrishnan, Avinash; Chu, Min-Cheol; Kim, Taik Nam; Cho, Seong Jai

2010-01-01

The purpose of this study was to determine the crack resistance behavior (K(R)) of human enamel in relation to its microstructure. Human molar teeth were precision cut, polished and tested using Vickers micro-indentation at different loads ranging from 0.98 to 9.8 N. Five indentation load levels were considered, 20 indentation cracks for each load level were introduced on the surface of the test specimen (10 indentations per tooth) and their variability was evaluated using Weibull statistics and an empirical model. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the crack morphology and propagation mechanisms involved. The results showed that enamel exhibited increasing cracking resistance (K(R)) with increasing load. It was found that the crack propagation mainly depended on the location and the microstructure it encountered. SEM showed the formation of crack bridges and crack deflection near the indentation crack tip. The crack mode was of Palmqvist type even at larger loads of 9.8 N. This was mainly attributed to the large process zone created by the interwoven lamellar rod like microstructure exhibited by the enamel surface. This study shows that there are still considerable prospects for improving dental ceramics and for mimicking the enamel structure developed by nature.

Effects of different black mediators on the shear strength of orthodontic bracket to the enamel treated with Nd-Yag laser

Science.gov (United States)

Huang, Shun-Te; Lin, I.-Shueng; Tsai, Chi-Cheng

1995-04-01

The Nd:YAG laser has ablation, crack, and crater effects on the dental enamel through black mediators which are very similar to the acid etching effects of phosphoric acid. This study was designed for searching how the different black mediators influence the shear strengths of the brackets bound to the enamel surfaces which were treated with the Nd:YAG laser. 90 bovine enamels divided into 5 groups were painted with 5 kinds of black mediators including Chinese ink, oil ink, black ball pen, water ink and black transfer paper. The enamel surfaces painted with black mediators were then radiated by Nd:YAG laser (ADL; American Dental Laser 300dl, power: 20 pps, 87.5 mj). Orthodontic brackets were bonded to the radiated surfaces. Then the shear strengths of the brackets to the enamels were measured by Instron. The results showed that the Chinese ink group and oil ink group has the strongest shear strength, ball pen group and water ink group showed the second strength, and the transfer paper group has the lowest shear strength. In addition, scanning electronic microscope also was used to observe the topographic changes of the enamel surfaces induced by the laser ablation.

Effect of Hydrofluoric Acid Etching Time on Titanium Topography, Chemistry, Wettability, and Cell Adhesion.

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R Zahran

Full Text Available Titanium implant surface etching has proven an effective method to enhance cell attachment. Despite the frequent use of hydrofluoric (HF acid, many questions remain unresolved, including the optimal etching time and its effect on surface and biological properties. The objective of this study was to investigate the effect of HF acid etching time on Ti topography, surface chemistry, wettability, and cell adhesion. These data are useful to design improved acid treatment and obtain an improved cell response. The surface topography, chemistry, dynamic wetting, and cell adhesiveness of polished Ti surfaces were evaluated after treatment with HF acid solution for 0, 2; 3, 5, 7, or 10 min, revealing a time-dependent effect of HF acid on their topography, chemistry, and wetting. Roughness and wetting increased with longer etching time except at 10 min, when roughness increased but wetness decreased. Skewness became negative after etching and kurtosis tended to 3 with longer etching time. Highest cell adhesion was achieved after 5-7 min of etching time. Wetting and cell adhesion were reduced on the highly rough surfaces obtained after 10-min etching time.

A comparison of fatigue crack growth in human enamel and hydroxyapatite.

Science.gov (United States)

Bajaj, Devendra; Nazari, Ahmad; Eidelman, Naomi; Arola, Dwayne D

2008-12-01

Cracks and craze lines are often observed in the enamel of human teeth, but they rarely cause tooth fracture. The present study evaluates fatigue crack growth in human enamel, and compares that to the fatigue response of sintered hydroxyapatite (HAp) with similar crystallinity, chemistry and density. Miniature inset compact tension (CT) specimens were prepared that embodied a small piece of enamel (N=8) or HAp (N=6). The specimens were subjected to mode I cyclic loads and the steady state crack growth responses were modeled using the Paris Law. Results showed that the fatigue crack growth exponent (m) for enamel (m=7.7+/-1.0) was similar to that for HAp (m=7.9+/-1.4), whereas the crack growth coefficient (C) for enamel (C=8.7 E-04 (mm/cycle)x(MPa m(0.5))(-m)) was significantly lower (pcrack growth in the enamel occurred primarily along the prism boundaries. In regions of decussation, the microstructure promoted microcracking, crack bridging, crack deflection and crack bifurcation. Working in concert, these mechanisms increased the crack growth resistance and resulted in a sensitivity to crack growth (m) similar to bone and lower than that of human dentin. These mechanisms of toughening were not observed in the crack growth response of the sintered HAp. While enamel is the most highly mineralized tissue of the human body, the microstructural arrangement of the prisms promotes exceptional resistance to crack growth.

Acquired acid resistance of human enamel treated with laser (Er:YAG laser and Co 2 laser and acidulated phosphate fluoride treatment: An in vitro atomic emission spectrometry analysis

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Anju Mathew

2013-01-01

Full Text Available Background: Dental caries is essentially a process of diffusion and dissolution. If the aspect of dissolution can be curtailed some degree of prevention can be achieved. Aims: The present study was carried out to evaluate and compare the effect of Er:YAG laser and Co 2 laser irradiation combined with acidulated phosphate fluoride treatment on in vitro acid resistance of human enamel. Design: An in vitro study was carried out on 30 human premolars to evaluate the enamel′s acid resistance using an atomic emission spectrometry analysis. Materials and Methods: A total of 60 enamel specimens were prepared from 30 human premolars and were randomly assigned to 6 groups: (1 Untreated (control; (2 1.23% acidulated phosphate fluoride (APF gel application alone for 4 min; (3 Er:YAG laser treatment alone; (4 Co 2 laser treatment alone; (5 Er:YAG laser + APF gel application; (6 Co 2 laser + APF gel application. The specimens were then individually immersed in 5 ml of acetate buffer solution (0.1 mol/L, pH 4.5 and incubated at 37°C for 24 h, and the acid resistance was evaluated by determining the calcium ion concentration using the atomic emission spectrometry. Statistical Analysis: An ANOVA model was constructed (P value of 0.05, followed by Tukey′s test for multiple pair wise comparisons of mean values. Results: Significant differences were found between the control group and the test groups ( P < 0.001. Conclusions: Combining acidulated phosphate fluoride with either Er:YAG or Co 2 laser had a synergistic effect in decreasing the enamel demineralization more than either fluoride treatment or laser treatment alone.

Effect of fluoride on ion exchange, remineralization and acid resistance of surface enamel

Energy Technology Data Exchange (ETDEWEB)

Aponte-Merced, L A; Feagin, F F [Alabama Univ., Birmingham (USA)

1979-01-01

In a system of constant ion activities the rates of F/sup -/ exchange in enamel, under conditions of exchange alone and remineralization, depended on the concentration of F/sup -/ in solutions. Acid resistance of surface minerals resulted from exchange of F/sup -/ for OH/sup -/ in the enamel at pH 7.0 and 4.5. The level of 0.5 mM NaF, compared to 0.05 and 5.0 mM, caused maximum rates of isotopic exchange of /sup 45/Ca and maximum acid resistance of enamel. Similarly low levels of F/sup -/ may be feasible for use in caries prevention in the absence and presence of remineralization.

Effect of Bioactive Glass air Abrasion on Shear Bond Strength of Two Adhesive Resins to Decalcified Enamel.

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Alireza Eshghi

2014-12-01

Full Text Available Bioactive glass air abrasion is a conservative technique to remove initial decalcified tissue and caries. This study examined the shear bond strength of composite resin to sound and decalcified enamel air-abraded by bioactive glass (BAG or alumina using etch-and-rinse and self-etch adhesives.Forty-eight permanent molars were root-amputated and sectioned mesiodistally. The obtained 96 specimens were mounted in acrylic resin; the buccal and lingual surfaces remained exposed. A demineralizing solution was used to decalcify half the specimens. Both sound and decalcified specimens were divided into two groups of alumina and bioactive glass air abrasion. In each group, the specimens were subdivided into two subgroups of Clearfil SE Bond or OptiBond FL adhesives (n=12. Composite resin cylinders were bonded on enamel surfaces cured and underwent thermocycling. The specimens were tested for shear bond strength. Data were analyzed using SPSS 16.0 and three-way ANOVA (α=0.05. Similar to the experimental groups, the enamel surface of one specimen underwent SEM evaluation.No significant differences were observed in composite resin bond strength subsequent to alumina or bioactive glass air abrasion preparation techniques (P=0.987. There were no statistically significant differences between the bond strength of etch-and-rinse and self-etch adhesive groups (P=1. Also, decalcified or intact enamel groups had no significant difference (P=0.918. However, SEM analysis showed much less enamel irregularities with BAG air abrasion compared to alumina air abrasion.Under the limitations of this study, preparation of both intact and decalcified enamel surfaces with bioactive glass air abrasion results in similar bond strength of composite resin in comparison with alumina air abrasion using etch-&-rinse or self-etch adhesives.

Effect of Bioactive Glass air Abrasion on Shear Bond Strength of Two Adhesive Resins to Decalcified Enamel

Science.gov (United States)

Eshghi, Alireza; Khoroushi, Maryam; Rezvani, Alireza

2014-01-01

Objective: Bioactive glass air abrasion is a conservative technique to remove initial decalcified tissue and caries. This study examined the shear bond strength of composite resin to sound and decalcified enamel air-abraded by bioactive glass (BAG) or alumina using etch-and-rinse and self-etch adhesives. Materials and Methods: Forty-eight permanent molars were root-amputated and sectioned mesiodistally. The obtained 96 specimens were mounted in acrylic resin; the buccal and lingual surfaces remained exposed. A demineralizing solution was used to decalcify half the specimens. Both sound and decalcified specimens were divided into two groups of alumina and bioactive glass air abrasion. In each group, the specimens were subdivided into two subgroups of Clearfil SE Bond or OptiBond FL adhesives (n=12). Composite resin cylinders were bonded on enamel surfaces cured and underwent thermocycling. The specimens were tested for shear bond strength. Data were analyzed using SPSS 16.0 and three-way ANOVA (α=0.05). Similar to the experimental groups, the enamel surface of one specimen underwent SEM evaluation. Results: No significant differences were observed in composite resin bond strength subsequent to alumina or bioactive glass air abrasion preparation techniques (P=0.987). There were no statistically significant differences between the bond strength of etch-and-rinse and self-etch adhesive groups (P=1). Also, decalcified or intact enamel groups had no significant difference (P=0.918). However, SEM analysis showed much less enamel irregularities with BAG air abrasion compared to alumina air abrasion. Conclusion: Under the limitations of this study, preparation of both intact and decalcified enamel surfaces with bioactive glass air abrasion results in similar bond strength of composite resin in comparison with alumina air abrasion using etch-&-rinse or self-etch adhesives. PMID:25628694

Indentation damage and mechanical properties of human enamel and dentin.

Science.gov (United States)

Xu, H H; Smith, D T; Jahanmir, S; Romberg, E; Kelly, J R; Thompson, V P; Rekow, E D

1998-03-01

Understanding the mechanical properties of human teeth is important to clinical tooth preparation and to the development of "tooth-like" restorative materials. Previous studies have focused on the macroscopic fracture behavior of enamel and dentin. In the present study, we performed indentation studies to understand the microfracture and deformation and the microcrack-microstructure interactions of teeth. It was hypothesized that crack propagation would be influenced by enamel rods and the dentino-enamel junction (DEJ), and the mechanical properties would be influenced by enamel rod orientation and tooth-to-tooth variation. Twenty-eight human third molars were used for the measurement of hardness, fracture toughness, elastic modulus, and energy absorbed during indentation. We examined the effect of enamel rod orientation by propagating cracks in the occlusal surface, and in the axial section in directions parallel and perpendicular to the occlusal surface. The results showed that the cracks in the enamel axial section were significantly longer in the direction perpendicular to the occlusal surface than parallel. The cracks propagating toward the DEJ were always arrested and unable to penetrate dentin. The fracture toughness of enamel was not single-valued but varied by a factor of three as a function of enamel rod orientation. The elastic modulus of enamel showed a significant difference between the occlusal surface and the axial section. It is concluded that the cracks strongly interact with the DEJ and the enamel rods, and that the mechanical properties of teeth are functions of microstructural orientations; hence, single values of properties (e.g., a single toughness value or a single modulus value) should not be used without information on microstructural orientation.

Mini-interfacial fracture toughness as a new validated enamel-bonding effectiveness test.

Science.gov (United States)

Pongprueksa, Pong; De Munck, Jan; Barreto, Bruno C; Karunratanakul, Kavin; Van Meerbeek, Bart

2016-09-01

Today׳s most commonly applied bonding effectiveness tests are criticized for their high variability and low reliability, the latter in particular with regard to measuring the actual strength of the adhesive interface. in continuation of previous research conducted at dentin, we hereby aimed to validate the novel mini-interfacial fracture toughness (mini-iFT) test on its applicability to assess bonding effectiveness of contemporary adhesives when bonded to enamel. The 3-step etch&rinse (E&R) adhesive OptiBond FL (Kerr), the 2-step self-etch (SE) adhesive Clearfil SE Bond (Kuraray Noritake) and the two multi-mode adhesives Clearfil S(3) Bond Plus (Kuraray Noritake) and Scotchbond Universal (3M ESPE), both used following a 2-step E&R and 1-step SE mode, were applied to clinically relevant, flattened enamel surfaces. A composite (Filtek Z100; 3M ESPE) build-up was made in layers. After 1-week water storage at 37°C, all specimens were sectioned perpendicular to the interface to obtain rectangular sticks. A mini-iFT notch was prepared at the adhesive-enamel interface using a thin diamond blade under water cooling. Finally, the specimens were loaded in a 4-point bending test until failure. the mini-iFT onto human enamel was significantly higher for the adhesives applied in E&R mode versus those applied in SE mode. The lowest mini-iFT was found for the adhesives applied following a 1-step SE approach. SEM fracture analysis revealed that all fractures originated at the adhesive-enamel interface and that the induced crack propagated preferentially along this interface. mini-iFT appeared a valid alternative method to assess the mechanical properties of adhesive-enamel interfaces. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microshear bond strength of a flowable resin to enamel according to the different adhesive systems

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Jeong-Ho Kim

2011-01-01

Full Text Available Objectives The purpose of this study was to compare the microshear bond strength (uSBS of two total-etch and four self-etch adhesive systems and a flowable resin to enamel. Materials and Methods Enamels of sixty human molars were used. They were divided into one of six equal groups (n = 10 by adhesives used; OS group (One-Step Plus, SB group (Single Bond, CE group (Clearfil SE Bond, TY group (Tyrian SPE/One-Step Plus, AP group (Adper Prompt L-Pop and GB group (G-Bond. After enamel surfaces were treated with six adhesive systems, a flowable composite resin (Filek Z 350 was bonded to enamel surface using Tygon tubes. the bonded specimens were subjected to uSBS testing and the failure modes of each group were observed under FE-SEM. Results 1. The uSBS of SB group was statistically higher than that of all other groups, and the uSBS of OS, SE and AP group was statistically higher than that of TY and GB group (p < 0.05. 2. The uSBS for TY group was statistically higher than that for GB group (p < 0.05. 3. Adhesive failures in TY and GB group and mixed failures in SB group and SE group were often analysed. One cohesive failure was observed in OS, SB, SE and AP group, respectively. Conclusions Although adhesives using the same step were applied the enamel sur

A Comparison of Fatigue Crack Growth in Human Enamel and Hydroxyapatite

OpenAIRE

Bajaj, Devendra; Nazari, Ahmad; Eidelman, Naomi; Arola, Dwayne

2008-01-01

Cracks and craze lines are often observed in the enamel of human teeth, but they rarely cause tooth fracture. The present study evaluates fatigue crack growth in human enamel, and compares that to the fatigue response of sintered hydroxyapatite (HAp) with similar crystallinity, chemistry and density. Miniature inset compact tension (CT) specimens were prepared that embodied a small piece of enamel (N=8) or HAp (N=6). The specimens were subjected to mode I cyclic loads and the steady state cra...

Microtensile bond strength to enamel affected by hypoplastic amelogenesis imperfecta.

Science.gov (United States)

Yaman, Batu Can; Ozer, Fusun; Cabukusta, Cigdem Sozen; Eren, Meltem M; Koray, Fatma; Blatz, Markus B

2014-02-01

This study compared the microtensile bond strengths (μTBS) of two different self-etching (SE) and etchand- rinse (ER) adhesive systems to enamel affected by hypoplastic amelogenesis imperfecta (HPAI) and analyzed the enamel etching patterns created by the two adhesive systems using scanning electron microscopy (SEM). Sixteen extracted HPAI-affected molars were used for the bond strength tests and 2 molars were examined under SEM for etching patterns. The control groups consisted of 12 healthy third molars for μTBS tests and two molars for SEM. Mesial and distal surfaces of the teeth were slightly ground flat. The adhesive systems and composite resin were applied to the flat enamel surfaces according to the manufacturers' instructions. The tooth slabs containing composite resin material on their mesial and distal surfaces were cut in the mesio-distal direction with a slow-speed diamond saw. The slabs were cut again to obtain square, 1-mm-thick sticks. Finally, each stick was divided into halves and placed in the μTBS tester. Bond strength tests were performed at a speed of 0.5 mm/min. Data were analyzed with two-way ANOVA and Tukey's tests. There was no significant difference between the bond strength values of ER and SE adhesives (p > 0.05). However, significant differences were found between HPAI and control groups (p systems provide similar bond strengths to HPAI-affected enamel surfaces.

Effect of Various Finishing Procedures on the Reflectivity (Shine) of Tooth Enamel - An In-vitro Study.

Science.gov (United States)

Patil, Harshal Ashok; Chitko, Shrikant Shrinivas; Kerudi, Veerendra Virupaxappa; Maheshwari, Amit Ratanlal; Patil, Neeraj Suresh; Tekale, Pawankumar Dnyandeo; Gore, Ketan Ashorao; Zope, Amit Ashok

2016-08-01

Reflectivity of an object is a good parameter for surface finish. As the patient evaluates finishing as a function of gloss/reflectivity/shine an attempt is made here to evaluate changes in surface finish with custom made reflectometer. The aim of the present study was to study the effect of various procedures during orthodontic treatment on the shine of enamel, using a custom made reflectometer. Sixty one extracted premolars were collected and each tooth was mounted on acrylic block. Reflectivity of the teeth was measured as compared to standard before any procedure. One tooth was kept as standard throughout the study. Sixty teeth were acid etched. Reflectivity was measured on custom made reflectometer and readings recorded. Same procedure was repeated after debonding. Then 60 samples were divided into three groups: Group 1 - Tungsten Carbide, Group 2 - Astropol, Group 3- Sof-Lex disc depending upon the finishing method after debonding and reflectivity was measured. The mean percentage of reflectivity after acid etching was 31.4%, debonding 45.5%, Tungsten carbide bur finishing (Group 1) was 58.3%, Astropol (Group 2) 72.8%, and Sof-Lex disc (Group 3) 84.4% as that to the standard. There was statistically very highly significant (p Group 2> Group 1. The primary goal was to restore the enamel to its original state after orthodontic treatment. The methods tested in this study could not restore the original enamel reflectivity.

Enamel erosion caused by the effervescent acid powder in Tiritón ice cream: An in vitro study.

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Katherine Beltrán

2014-12-01

Full Text Available The aim of this study was to visualize the erosive effect on human dental enamel of effervescent acid powder in the Tiritón ice cream (Savory, Nestle, Vevey, Switzerland. The erosive potential of Tiritón ice cream was determined in in vitro conditions by submitting 5 enamel pieces from 3 healthy first molars. The samples were submitted to the mixture of saliva from a girl without cavity incidence and the effervescent powder in the Tiritón ice cream, at 10, 20, 30, 40 and 50 seconds, then the results were measured by scanning electron microscopy (SEM and measurement of pH. All specimens showed pH 3.0. SEM showed increasing degrees of erosion with longer periods of exposure. The Tiritón ice cream generates a much larger acid solution than necessary for the onset of the dissolution of enamel which subsequently causes susceptibility to dental cavities and erosion, higher than reported for other candies. The images obtained by SEM made possible to visualize clearly the erosive effect produced by the effervescent acid powder in periods of exposure of less than a minute.

Effect of newer antioxidants on the bond strength of composite on bleached enamel

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M Manoharan

2016-01-01

Full Text Available Aim: The study aims to evaluate the effect of the application of two antioxidants on the bond strength of composite resin to bleached enamel. Materials and Methods: Eighty enamel surfaces were obtained from forty human extracted premolars. Specimens were randomly divided into four groups (n = 20. Group 1: No bleaching (control; Group 2a: Bleaching with 15% carbamide peroxide gel; Group 2b: Bleaching, followed by application of 10% sodium ascorbate gel; Group 2c: Bleaching, followed by application of 5% proanthocyanidin agent. Surfaces were etched followed by application of total etch bonding system, and composite resin cylinders were bonded. Specimens were tested for shear bond strength. Statistical Analysis Used: One-way analysis of variance was used for multiple group comparison and post hoc Tukey′s test for individual group-wise comparison. Results: Significantly higher shear bond strength values were observed in Group 2c and 2b as compared with Group 1 and 2a (P < 0.05. Among the antioxidants, Group 2c showed significantly higher shear bond strength values than Group 2b (P < 0.05. Conclusion: It can be concluded that the use of antioxidant before bonding procedures on bleached enamel completely neutralizes the deleterious effects of bleaching and increases the bond strength significantly.

Changes in composition and enamel demineralization inhibition activities of gallic acid at different pH values

NARCIS (Netherlands)

Zhang, J.; Huang, X.; Huang, S.; Deng, M.; Xie, X.; Liu, M.; Liu, H.; Zhou, X.; Li, J.; ten Cate, J.M.

2015-01-01

Background. Gallic acid (GA) has been shown to inhibit demineralization and enhance remineralization of enamel; however, GA solution is highly acidic. This study was to investigate the stability of GA solutions at various pH and to examine the resultant effects on enamel demineralization. Methods.

Alteration of dentin-enamel mechanical properties due to dental whitening treatments.

Science.gov (United States)

Zimmerman, B; Datko, L; Cupelli, M; Alapati, S; Dean, D; Kennedy, M

2010-05-01

The mechanical properties of dentin and enamel affect the reliability and wear properties of a tooth. This study investigated the influence of clinical dental treatments and procedures, such as whitening treatments or etching prior to restorative procedures. Both autoclaved and non-autoclaved teeth were studied in order to allow for both comparison with published values and improved clinical relevance. Nanoindentation analysis with the Oliver-Pharr model provided elastic modulus and hardness across the dentin-enamel junction (DEJ). Large increases were observed in the elastic modulus of enamel in teeth that had been autoclaved (52.0 GPa versus 113.4 GPa), while smaller increases were observed in the dentin (17.9 GPa versus 27.9 GPa). Likewise, there was an increase in the hardness of enamel (2.0 GPa versus 4.3 GPa) and dentin (0.5 GPa versus 0.7 GPa) with autoclaving. These changes suggested that the range of elastic modulus and hardness values previously reported in the literature may be partially due to the sterilization procedures. Treatment of the exterior of non-autoclaved teeth with Crest Whitestrips, Opalescence or UltraEtch caused changes in the mechanical properties of both the enamel and dentin. Those treated with Crest Whitestrips showed a reduction in the elastic modulus of enamel (55.3 GPa to 32.7 GPa) and increase in the elastic modulus of dentin (17.2 GPa to 24.3 GPa). Opalescence treatments did not significantly affect the enamel properties, but did result in a decrease in the modulus of dentin (18.5 GPa to 15.1 GPa). Additionally, as expected, UltraEtch treatment decreased the modulus and hardness of enamel (48.7 GPa to 38.0 GPa and 1.9 GPa to 1.5 GPa, respectively) and dentin (21.4 GPa to 15.0 GPa and 1.9 GPa to 1.5 GPa, respectively). Changes in the mechanical properties were linked to altered protein concentration within the tooth, as evidenced by fluorescence microscopy and Fourier transform infrared spectroscopy. Published by Elsevier Ltd.

Heat Transfer Behavior across the Dentino-Enamel Junction in the Human Tooth.

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Lin Niu

Full Text Available During eating, the teeth usually endure the sharply temperature changes because of different foods. It is of importance to investigate the heat transfer and heat dissipation behavior of the dentino-enamel junction (DEJ of human tooth since dentine and enamel have different thermophysical properties. The spatial and temporal temperature distributions on the enamel, dentine, and pulpal chamber of both the human tooth and its discontinuous boundaries, were measured using infrared thermography using a stepped temperature increase on the outer boundary of enamel crowns. The thermal diffusivities for enamel and dentine were deduced from the time dependent temperature change at the enamel and dentine layers. The thermal conductivities for enamel and dentine were calculated to be 0.81 Wm-1K-1 and 0.48 Wm-1K-1 respectively. The observed temperature discontinuities across the interfaces between enamel, dentine and pulp-chamber layers were due to the difference of thermal conductivities at interfaces rather than to the phase transformation. The temperature gradient distributes continuously across the enamel and dentine layers and their junction below a temperature of 42°C, whilst a negative thermal resistance is observed at interfaces above 42°C. These results suggest that the microstructure of the dentin-enamel junction (DEJ junction play an important role in tooth heat transfer and protects the pulp from heat damage.

In vitro evaluation of the erosive potential of viscosity-modified soft acidic drinks on enamel.

Science.gov (United States)

Aykut-Yetkiner, Arzu; Wiegand, Annette; Ronay, Valerie; Attin, Rengin; Becker, Klaus; Attin, Thomas

2014-04-01

The objective of this in vitro study was to investigate the effect of viscosity-modified soft acidic drinks on enamel erosion. A total of 108 bovine enamel samples (∅ = 3 mm) were embedded in acrylic resin and allocated into six groups (n = 18). Soft acidic drinks (orange juice, Coca-Cola, Sprite) were used both in their regular forms and at a kinetic viscositiy of 5 mm(2)/s, which was adjusted by adding hydroxypropyl cellulose. All solutions were pumped over the enamel surface from a reservoir with a drop rate of 3 ml/min. Each specimen was eroded for 10 min at 20 °C. Erosion of enamel surfaces was measured using profilometry. Data were analyzed using independent t tests and one-way ANOVAs (p Coca-Cola, 5.60 ± 1.04 μm; Sprite, 5.49 ± 0.94 μm; orange juice, 1.35 ± 0.4 μm) than for the viscosity-modified drinks (Coca-Cola, 4.90 ± 0.34 μm; Sprite, 4.46 ± 0.39 μm; orange juice, 1.10 ± 0.22 μm). For both regular and viscosity-modified forms, Coca-Cola and Sprite caused higher enamel loss than orange juice. Increasing the viscosity of acidic soft drinks to 5 mm(2)/s reduced enamel erosion by 12.6-18.7 %. The erosive potential of soft acidic drinks is not only dependent on various chemical properties but also on the viscosity of the acidic solution and can be reduced by viscosity modification.

Bond strength of composite resin to enamel: assessment of two ethanol wet-bonding techniques.

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Maryam Khoroushi

2014-04-01

Full Text Available Ethanol wet-bonding (EWB technique has been stated to decrease degradation of resin-dentin bond. This study evaluated the effect of two EWB techniques on composite resin-to-enamel bond strength.Silicon carbide papers were used to produce flat enamel surfaces on the buccal faces of forty-five molars. OptiBond FL (OFL adhesive was applied on enamel surfaces in three groups of 15 namely: Enamel surface and OFL (control;Protocol 1 of the EWB technique: absolute ethanol was applied to water-saturated acid-etched enamel surfaces for 1 minute before the application of ethanol-solvated hydrophobic adhesive resin of OFL 3 times;Protocol 2: progressive ethanol replacement; water was gradually removed from the enamel matrix using ascending ethanol concentrations before OFL application. Composite build-ups were made and the specimens were stored for 24 hours at 37°C and 100% relative humidity. Shear bond strength test was performed using a universal testing machine at 1 mm/min crosshead speed. Fracture patterns were evaluated microscopically. Data were analyzed with one-way ANOVA and Fisher's exact test (α=0.05.There were no significant differences in bond strength between the groups (P=0.73. However, regarding failure patterns, the highest cohesive enamel fractures were recorded in groups 2 and 3.In this study, although both methods of EWB did not influence immediate bond strength of composite resin to enamel, the majority of failure patterns occurred cohesively in enamel.

Micromorphological characterization of adhesive interface of sound dentin and total-etch and self-etch adhesives.

Science.gov (United States)

Drobac, Milan; Stojanac, Igor; Ramić, Bojana; Premović, Milica; Petrović, Ljubomir

2015-01-01

The ultimate goal in restorative dentistry has always been to achieve strong and permanent bond between the dental tissues and filling materials. It is not easy to achieve this task because the bonding process is different for enamel and dentin-dentin is more humid and more organic than enamel. It is moisture and organic nature of dentin that make this hard tissue very complex to achieve adhesive bond. One of the first and most widely used tools for examining the adhesive bond between hard dental tissues and composite restorative materials is scanning electron microscopy. The aim of this study was scanning electron microscopy analyzes the interfacial micro morphology of total-etch and self-etch adhesives. Micro morphological characteristics of interface between total-etch adhesive (Prime & Bond NT) in combination with the corresponding composite (Ceram X Mono) were compared with those of self-etching adhesive (AdheSE One) in, combination with the corresponding composite (Tetric EvoCeram). The specimens were observed under 1000 x magnification of scanning electron microscopy (JEOL, JSM-6460 Low Vacuum). Measurement of the thickness of the hybrid layer of the examined com posite systems was performed with the software of the device used (NIH Image Analyser). Micromorphological analysis of interface showed that the hybrid layer in sound dentin was well formed, its average thickness being 2.68 microm, with a large number of resin tags and a large amount of lateral branches for specimens with a composite system Prime & Bond NT-Ceram X Mono. However, the specimens' with composite systems Adhese One-Tetric EvoCeram did not show the presence of hybrid layer and the resin tags were poorly represented. The results of this study suggest that total-etch adhesives bond better with sound dentin than self-etch adhesive.

On the R-curve behavior of human tooth enamel.

Science.gov (United States)

Bajaj, Devendra; Arola, Dwayne D

2009-08-01

In this study the crack growth resistance behavior and fracture toughness of human tooth enamel were quantified using incremental crack growth measures and conventional fracture mechanics. Results showed that enamel undergoes an increase in crack growth resistance (i.e. rising R-curve) with crack extension from the outer to the inner enamel, and that the rise in toughness is a function of distance from the dentin enamel junction (DEJ). The outer enamel exhibited the lowest apparent toughness (0.67+/-0.12 MPam(0.5)), and the inner enamel exhibited a rise in the growth toughness from 1.13 MPam(0.5)/mm to 3.93 MPam(0.5)/mm. The maximum crack growth resistance at fracture (i.e. fracture toughness (K(c))) ranged from 1.79 to 2.37 MPam(0.5). Crack growth in the inner enamel was accompanied by a host of mechanisms operating from the micro- to the nano-scale. Decussation in the inner enamel promoted crack deflection and twist, resulting in a reduction of the local stress intensity at the crack tip. In addition, extrinsic mechanisms such as bridging by unbroken ligaments of the tissue and the organic matrix promoted crack closure. Microcracking due to loosening of prisms was also identified as an active source of energy dissipation. In summary, the unique microstructure of enamel in the decussated region promotes crack growth toughness that is approximately three times that of dentin and over ten times that of bone.

Wear properties of dental ceramics and porcelains compared with human enamel.

Science.gov (United States)

D'Arcangelo, Camillo; Vanini, Lorenzo; Rondoni, Giuseppe D; De Angelis, Francesco

2016-03-01

Contemporary pressable and computer-aided design/manufacturing (CAD/CAM) ceramics exhibit good mechanical and esthetic properties. Their wear resistance compared with human enamel and traditional gold based alloys needs to be better investigated. The purpose of this in vitro study was to compare the 2-body wear resistance of human enamel, gold alloy, and 5 different dental ceramics, including a recently introduced zirconia-reinforced lithium silicate ceramic (Celtra Duo). Cylindrical specimens were fabricated from a Type III gold alloy (Aurocast8), 2 hot pressed ceramics (Imagine PressX, IPS e.max Press), 2 CAD/CAM ceramics (IPS e.max CAD, Celtra Duo), and a CAD/CAM feldspathic porcelain (Vitablocs Mark II) (n=10). Celtra Duo was tested both soon after grinding and after a subsequent glaze firing cycle. Ten flat human enamel specimens were used as the control group. All specimens were subjected to a 2-body wear test in a dual axis mastication simulator for 120000 loading cycles against yttria stabilized tetragonal zirconia polycrystal cusps. The wear resistance was analyzed by measuring the vertical substance loss (mm) and the volume loss (mm(3)). Antagonist wear (mm) was also recorded. Data were statistically analyzed with 1-way ANOVA tests (α=.05). The wear depth (0.223 mm) of gold alloy was the closest to that of human enamel (0.217 mm), with no significant difference (P>.05). The greatest wear was recorded on the milled Celtra Duo (wear depth=0.320 mm), which appeared significantly less wear resistant than gold alloy or human enamel (Pceramics did not statistically differ in comparison with the human enamel. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Enamel and dentin bond strength following gaseous ozone application.

Science.gov (United States)

Cadenaro, Milena; Delise, Chiara; Antoniollo, Francesca; Navarra, Ottavia Chiara; Di Lenarda, Roberto; Breschi, Lorenzo

2009-08-01

To evaluate the effects of gaseous ozone application on enamel and dentin bond strength produced by two self-etching adhesive systems. The shear bond strength test was conducted to assess adhesion on enamel (protocol 1), while the microtensile bond strength test was performed on dentin (protocol 2). Protocol 1: 96 bovine incisors were randomly divided into 4 groups, and enamel surfaces were bonded in accordance with the following treatments: (1E) ozone + Clearfil Protect Bond; (2E) Clearfil Protect Bond (control); (3E) ozone + Xeno III; (4E) Xeno III (control). Ozone gas was applied for 80 s. Shear bond strength was measured with a universal testing machine. Protocol 2: 40 noncarious human molars were selected. Middle/deep dentin was exposed and bonded in accordance with the following treatments: (1D) ozone+Clearfil Protect Bond; (2D) Clearfil Protect Bond (control); (3D) ozone+Xeno III (4D) Xeno III (control). Four-mm-thick buildups were built on the adhesives, then specimens were sectioned in accordance with the nontrimming technique. Specimens were stressed until failure occurred, and failure modes were analyzed. Shear bond and microtensile bond strength data were analyzed using two-way ANOVA and Tukey's post-hoc test. No statistical differences were found between ozone treated specimens and controls, neither on enamel nor on dentin irrespective of the tested adhesive. Clearfil Protect Bond showed higher bond strength to enamel than Xeno III, irrespective of the ozone treatment (p enamel and dentin bond strength.

Modelling of micromachining of human tooth enamel by erbium laser radiation

Energy Technology Data Exchange (ETDEWEB)

Belikov, A V; Skrypnik, A V; Shatilova, K V [St. Petersburg National Research University of Information Technologies, Mechanics and Optics, St. Petersburg (Russian Federation)

2014-08-31

We consider a 3D cellular model of human tooth enamel and a photomechanical cellular model of enamel ablation by erbium laser radiation, taking into account the structural peculiarities of enamel, energy distribution in the laser beam cross section and attenuation of laser energy in biological tissue. The surface area of the texture in enamel is calculated after its micromachining by erbium laser radiation. The influence of the surface area on the bond strength of enamel with dental filling materials is discussed. A good correlation between the computer simulation of the total work of adhesion and experimentally measured bond strength between the dental filling material and the tooth enamel after its micromachining by means of YAG : Er laser radiation is attained. (laser biophotonics)

Modelling of micromachining of human tooth enamel by erbium laser radiation

International Nuclear Information System (INIS)

Belikov, A V; Skrypnik, A V; Shatilova, K V

2014-01-01

We consider a 3D cellular model of human tooth enamel and a photomechanical cellular model of enamel ablation by erbium laser radiation, taking into account the structural peculiarities of enamel, energy distribution in the laser beam cross section and attenuation of laser energy in biological tissue. The surface area of the texture in enamel is calculated after its micromachining by erbium laser radiation. The influence of the surface area on the bond strength of enamel with dental filling materials is discussed. A good correlation between the computer simulation of the total work of adhesion and experimentally measured bond strength between the dental filling material and the tooth enamel after its micromachining by means of YAG : Er laser radiation is attained. (laser biophotonics)

Investigating Micro-Tensile Bond Strength of Silorane Based Composite in Enamel Surfaces Prepared by Er:YAG Laser vs. Bur-Cut

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AR Daneshkazemi

2014-10-01

Full Text Available Introduction: Recently, Er:YAG laser has been used for tooth preparations and silorane-based composites have been introduced to dentistry, though investigating this type of composites has received scant attention. Therefore, the aim of this study was to compare microtensile bond strength (MTBS of silorane- based composite (Filtek P90 3M/USA to enamel sufaces, prepared by Er:YAG laser irradiation versus bur cut. Methods:Same sized cavities were prepared by ER:YAG laser and bur on the enamel of 20 extracted teeth which were randomly divided into 4 groups:E1 laser + acid etching, E2: laser, E3: bur + acid etching, E4: bur. Then primer, adhesive and P60 resin composite were utilized according to the manufacturer instructions. After thermocycling, 20 samples were created in the form of an hour glass model with 1 mm2 slices in each group, and were tested by SD Mechatronic MTD 500 (Germany machine with cross head speed of 1mm/min to create the fracture. The failure mode was assessed under stereomicroscope (ZTX-3E, Zhejiang/China, and the study data were analysed by ANOVA test. Results: The study results revealed that highest and lowest microtensile bond strength belonged to E3 and E2 group respectively. No significant differences were observed between the tested groups(p= 0.213. Highest and lowest modes of failure were adhesive and cohesive respectively. ANOVA results did not demonstrate any significant differences between groups(p=0.845. Conclusion: Laser-prepared or bur-prepared cavities with or without etching and silorane based composite could not significantly affect MTBS in order to enamel.

Effects of Different Combinations of Er:YAG Laser-Adhesives on Enamel Demineralization and Bracket Bond Strength.

Science.gov (United States)

Çokakoğlu, Serpil; Nalçacı, Ruhi; Üşümez, Serdar; Malkoç, Sıddık

2016-04-01

The purpose of this study was to investigate the demineralization around brackets and shear bond strength (SBS) of brackets bonded to Er:YAG laser-irradiated enamel at different power settings with various adhesive systems combinations. A total of 108 premolar teeth were used in this study. Teeth were assigned into three groups according to the etching procedure, then each group divided into three subgroups based on the application of different adhesive systems. There were a total of nine groups as follows. Group 1: Acid + Transbond XT Primer; group 2: Er:YAG (100 mJ, 10 Hz) etching + Transbond XT Primer; group 3: Er:YAG (200 mJ, 10 Hz) etching + Transbond XT Primer; group 4: Transbond Plus self-etching primer (SEP); group 5: Er:YAG (100 mJ, 10 Hz) etching + Transbond Plus SEP; group 6: Er:YAG (200 mJ, 10 Hz) etching + Transbond Plus SEP; group 7: Clearfil Protect Bond; group 8: Er:YAG (100 mJ, 10 Hz) etching + Clearfil Protect Bond; group 9: Er:YAG (200 mJ, 10 Hz) etching + Clearfil Protect Bond. Brackets were bonded with Transbond XT Adhesive Paste in all groups. Teeth to be evaluated for demineralization and SBS were exposed to pH and thermal cyclings, respectively. Then, demineralization samples were scanned with micro-CT to determine lesion depth values. For SBS test, a universal testing machine was used and adhesive remnant was index scored after debonding. Data were analyzed statistically. No significant differences were found among the lesion depth values of the various groups, except for G7 and G8, in which the lowest values were recorded. The lowest SBS values were in G7, whereas the highest were in G9. The differences between the other groups were not significant. Er:YAG laser did not have a positive effect on prevention of enamel demineralization. When two step self-etch adhesive is preferred for bonding brackets, laser etching at 1 W (100 mJ, 10 Hz) is suggested to improve SBS of brackets.

In vitro study of the effect of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate on acid-softened enamel.

Science.gov (United States)

Rege, Aarti; Heu, Rod; Stranick, Michael; Sullivan, Richard J

2014-01-01

To investigate the possible mode of action of a dentifrice containing 8% arginine and calcium carbonate (Pro-Argin Technology), and sodium monofluorophosphate in delivering the benefits of preventing acid erosion and rehardening acid-softened enamel. The surfaces of acid-softened bovine enamel specimens were evaluated after application of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate in vitro. Scanning Electron Microscopy (SEM), Electronic Spectrometry for Chemical Analysis (ESCA), and Secondary Ion Mass Spectrometry (SIMS) were used to characterize the enamel surfaces. Exposure of pristine enamel surfaces to citric acid resulted in clear roughening of the surface. Multiple applications of a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate to the surface of the enamel resulted in the disappearance of the microscopic voids observed by SEM as a function of treatment applications. The ESCA analysis demonstrated that both the nitrogen and carbonate levels increased as the number of treatments increased, which provides evidence that arginine and calcium carbonate were bound to the surface. Observance of arginine's signature mass fragmentation pattern by SIMS analysis confirmed the identity of arginine on the enamel surface. A series of in vitro experiments has demonstrated a possible mode of action by which a dentifrice containing 8% arginine, calcium carbonate, and sodium monofluorophosphate delivers the benefits of preventing acid erosion and rehardening acid-softened enamel. The combination of arginine and calcium carbonate adheres to the enamel surface and helps to fill the microscopic gaps created by acid, which in turn helps repair the enamel and provides a protective coating against future acid attacks.

Helium ion microscopy of enamel crystallites and extracellular tooth enamel matrix.

Science.gov (United States)

Bidlack, Felicitas B; Huynh, Chuong; Marshman, Jeffrey; Goetze, Bernhard

2014-01-01

An unresolved problem in tooth enamel studies has been to analyze simultaneously and with sufficient spatial resolution both mineral and organic phases in their three dimensional (3D) organization in a given specimen. This study aims to address this need using high-resolution imaging to analyze the 3D structural organization of the enamel matrix, especially amelogenin, in relation to forming enamel crystals. Chemically fixed hemi-mandibles from wild type mice were embedded in LR White acrylic resin, polished and briefly etched to expose the organic matrix in developing tooth enamel. Full-length amelogenin was labeled with specific antibodies and 10 nm immuno-gold. This allowed us to use and compare two different high-resolution imaging techniques for the analysis of uncoated samples. Helium ion microscopy (HIM) was applied to study the spatial organization of organic and mineral structures, while field emission scanning electron microscopy (FE-SEM) in various modes, including backscattered electron detection, allowed us to discern the gold-labeled proteins. Wild type enamel in late secretory to early maturation stage reveals adjacent to ameloblasts a lengthwise parallel alignment of the enamel matrix proteins, including full-length amelogenin proteins, which then transitions into a more heterogeneous appearance with increasing distance from the mineralization front. The matrix adjacent to crystal bundles forms a smooth and lacey sheath, whereas between enamel prisms it is organized into spherical components that are interspersed with rod-shaped protein. These findings highlight first, that the heterogeneous organization of the enamel matrix can be visualized in mineralized en bloc samples. Second, our results illustrate that the combination of these techniques is a powerful approach to elucidate the 3D structural organization of organic matrix molecules in mineralizing tissue in nanometer resolution.

Helium ion microscopy of enamel crystallites and extracellular tooth enamel matrix

Directory of Open Access Journals (Sweden)

Felicitas B Bidlack

2014-10-01

Full Text Available An unresolved problem in tooth enamel studies has been to analyze simultaneously and with sufficient spatial resolution both mineral and organic phases in their three dimensional (3D organization in a given specimen. This study aims to address this need using high-resolution imaging to analyze the 3D structural organization of the enamel matrix, especially amelogenin, in relation to forming enamel crystals. Chemically fixed hemi-mandibles from wild type mice were embedded in LR White acrylic resin, polished and briefly etched to expose the organic matrix in developing tooth enamel. Full-length amelogenin was labeled with specific antibodies and 10 nm immuno-gold. This allowed us to use and compare two different high-resolution imaging techniques for the analysis of uncoated samples. Helium ion microscopy (HIM was applied to study the spatial organization of organic and mineral structures, while field emission scanning electron microscopy (FE-SEM in various modes, including backscattered electron detection, allowed us to discern the gold-labeled proteins. Wild type enamel in late secretory to early maturation stage reveals adjacent to ameloblasts a lengthwise parallel alignment of the enamel matrix proteins, including full-length amelogenin proteins, which then transitions into a more heterogeneous appearance with increasing distance from the mineralization front. The matrix adjacent to crystal bundles forms a smooth and lacey sheath, whereas between enamel prisms it is organized into spherical components that are interspersed with rod-shaped protein. These findings highlight first, that the heterogeneous organization of the enamel matrix can be visualized in mineralized en bloc samples. Second, our results illustrate that the combination of these techniques is a powerful approach to elucidate the 3D structural organization of organic matrix molecules in mineralizing tissue in nanometer resolution.

Enamel softening with Coca-Cola and rehardening with milk or saliva.

Science.gov (United States)

Gedalia, I; Dakuar, A; Shapira, L; Lewinstein, I; Goultschin, J; Rahamim, E

1991-06-01

Rehardening effects by cow's milk and by secreted saliva were investigated, in situ, following softening of human enamel with an acidic beverage (Coca-Cola). Volunteers wearing orthodontic removable appliances participated in the study. The intra-oral test was chosen for measuring microhardness of enamel slabs inserted into the dental appliance. The softening and the rehardening degrees were defined as the alterations between initial- and experimental-microhardness value at the enamel surface. In addition, SEM photos were prepared from the initial and experimental stages. Exposure of enamel slabs to the acidic beverage during 1 hour had a softening effect as expressed by the hardness decrease and visualized by the SEM photo. Rehardening effects following milk or saliva exposures respectively were evident, presumably due to deposited organic and mineral material on the enamel surface.

Performance of a universal adhesive on etched and non-etched surfaces: Do the results match the expectations?

Energy Technology Data Exchange (ETDEWEB)

Grégoire, Geneviève, E-mail: genevieve.gregoire@univ-tlse3.fr [Department of Biomaterials, Faculty of Odontology, University Toulouse III, 31062 Toulouse (France); Sharrock, Patrick, E-mail: patrick.sharrock@gmail.com [CNRS UMR 5302, University Toulouse III, Mines-Albi, 81013 Albi (France); Prigent, Yann, E-mail: prigent@chimie.ups-tlse.fr [Institut de Chimie de Toulouse (ICT) – FR 2599, Faculté des Sciences et de l' Ingénierie, University Toulouse III, 31062 Toulouse (France)

2016-09-01

A universal adhesive was applied to human dentin in both the etched and rinsed state and the normal non etched state, to compare the resulting properties and detect any significant differences. The study focused on observations of the hybrid layer by scanning electron microscopy and on fluid permeation measurements as a function of time. Spectroscopic characterizations included infrared and differential calorimetric curves of the samples. The results obtained show non-statistically significant fluid permeability between the two sample types. Both the etched and rinsed samples and the non-etched ones showed similar homogeneous hybrid layers that reduced the fluid flow, and corresponded to well spread polymer coatings. The infrared results illustrated the spectra obtained on going from the outside adhesive layer to the inside portion of the dentin-polymer interface and did not reveal any intermediate zone resembling demineralized collagen that would be water saturated and not infiltrated with adhesive. The Differential Scanning Calorimetry (DSC) curves corresponded to the curves obtained with ethanol wet bonding in that free water (melting at 0 °C) was removed by the universal adhesive, and that no collagen melting was observed for the non-etched samples. The Diffusion-Ordered Spectroscopy Nuclear Magnetic Resonance (DOSY NMR) spectrum of the virgin adhesive showed the presence of water and ethanol solvents and indicated that several monomer or prepolymer molecules were present with multiple acrylic functional groups with diffusion coefficients related to molecular weights. Overall, the results show that universal adhesive can be used in the milder self-etch mode and that more aggressive etch and rinse procedure can be reserved for the occasions with sclerotic dentin or enamel regions more difficult to treat.

Performance of a universal adhesive on etched and non-etched surfaces: Do the results match the expectations?

International Nuclear Information System (INIS)

Grégoire, Geneviève; Sharrock, Patrick; Prigent, Yann

2016-01-01

A universal adhesive was applied to human dentin in both the etched and rinsed state and the normal non etched state, to compare the resulting properties and detect any significant differences. The study focused on observations of the hybrid layer by scanning electron microscopy and on fluid permeation measurements as a function of time. Spectroscopic characterizations included infrared and differential calorimetric curves of the samples. The results obtained show non-statistically significant fluid permeability between the two sample types. Both the etched and rinsed samples and the non-etched ones showed similar homogeneous hybrid layers that reduced the fluid flow, and corresponded to well spread polymer coatings. The infrared results illustrated the spectra obtained on going from the outside adhesive layer to the inside portion of the dentin-polymer interface and did not reveal any intermediate zone resembling demineralized collagen that would be water saturated and not infiltrated with adhesive. The Differential Scanning Calorimetry (DSC) curves corresponded to the curves obtained with ethanol wet bonding in that free water (melting at 0 °C) was removed by the universal adhesive, and that no collagen melting was observed for the non-etched samples. The Diffusion-Ordered Spectroscopy Nuclear Magnetic Resonance (DOSY NMR) spectrum of the virgin adhesive showed the presence of water and ethanol solvents and indicated that several monomer or prepolymer molecules were present with multiple acrylic functional groups with diffusion coefficients related to molecular weights. Overall, the results show that universal adhesive can be used in the milder self-etch mode and that more aggressive etch and rinse procedure can be reserved for the occasions with sclerotic dentin or enamel regions more difficult to treat.

Shear bond strength evaluation of chemically-cured and light-cured orthodontic adhesives after enamel deproteinization with 5.25% sodium hypochlorite

Science.gov (United States)

Salim, J. C.; Krisnawati; Purbiati, M.

2017-08-01

This study aimed to assess the effect of enamel deproteinization with 5.25% sodium hypochlorite (NaOCl) before etching on the shear bond strength (SBS) of Unite (UN; 3M Unitek) and Xihu-BIOM adhesive (XB). Fifty-two maxillary first premolars were divided into four groups: (1) UN and (2) XB according to manufacturer’s recommendation and (3) UN and (4) XB deproteinized with 5.25% NaOCl. Brackets were bonded, and a mechanical test was performed using a universal testing machine. The mean SBS value for groups A1, A2, B1, and B2 was 13.51 ± 2.552, 14.36 ± 2.902, 16.43 ± 2.615, and 13.05 ± 2.348 MPa, respectively. A statistically significant difference in SBSs was observed between chemically cured groups and between group B (p 0.05). NaOCl enamel deproteinization before acid etching has a significant effect on the SBS of Unite adhesive, but not on that of the Xihu-BIOM adhesive. Furthermore, a significant difference in the SBS of Unite and Xihu-BIOM adhesives within the enamel deproteinization group was observed in this study.

The effect of time in the exposure of theobromine gel to enamel and surface hardness after demineralization with 1% citric acid

Science.gov (United States)

Irawan, M. I. P.; Noerdin, A.; Eriwati, Y. K.

2017-08-01

Theobromine is one of the alkaloid compounds that can be found in cacao (Theobroma cacao). It is said that theobromine can prevent enamel demineralization. The aim of this research was to evaluate the effect of different exposure times to 200 mg/L theobromine gel on enamel microhardness after demineralization in 1% citric acid. Twenty-eight specimens of human premolar teeth were divided into four groups and were immersed in 1% citric acid (pH 4) for 2.5 minutes. Then 200 mg/L theobromine gel was exposed to the specimens for 16 minutes (n = 7), 48 minutes (n = 7), and 96 minutes (n = 7). Enamel microhardness (KHN) values were tested using the Knoop Microhardness Tester (Shimadzu, Japan) using a 50-gram load for 5 seconds. A statistical test was performed using the Friedman test, Wilcoxon test, Kruskal-Wallis test, and Mann-Whitney test. The results showed a significant decrease, of microhardness values after demineralization with 1% citric acid. There was also a significant increase in hardness (penamel microhardness.

Sphingoid bases inhibit acid-induced demineralization of hydroxyapatite

NARCIS (Netherlands)

Valentijn-Benz, M.; van 't Hof, W.; Bikker, F.J.; Nazmi, K.; Brand, H.S.; Sotres, J.; Lindh, L.; Arnebrant, T.; Veerman, E.C.I.

2015-01-01

Calcium hydroxyapatite (HAp), the main constituent of dental enamel, is inherently susceptible to the etching and dissolving action of acids, resulting in tooth decay such as dental caries and dental erosion. Since the prevalence of erosive wear is gradually increasing, there is urgent need for

Role of Prism Decussation on Fatigue Crack Growth and Fracture of Human Enamel

OpenAIRE

Bajaj, Devendra; Arola, Dwayne

2009-01-01

The role of prism decussation on the crack growth resistance of human enamel is evaluated. Miniature inset Compact Tension (CT) specimens embodying a section of cuspal enamel were subjected to Mode I cyclic or monotonic loads. Cracks were grown in either the forward (from outer enamel inwards) or reverse (from inner enamel outwards) direction and the responses were compared quantitatively. Results showed that the outer enamel exhibits lower resistance to the inception and growth of cracks. Re...

Measurement uncertainty associated with chromatic confocal profilometry for 3D surface texture characterization of natural human enamel.

Science.gov (United States)

Mullan, F; Bartlett, D; Austin, R S

2017-06-01

To investigate the measurement performance of a chromatic confocal profilometer for quantification of surface texture of natural human enamel in vitro. Contributions to the measurement uncertainty from all potential sources of measurement error using a chromatic confocal profilometer and surface metrology software were quantified using a series of surface metrology calibration artifacts and pre-worn enamel samples. The 3D surface texture analysis protocol was optimized across 0.04mm 2 of natural and unpolished enamel undergoing dietary acid erosion (pH 3.2, titratable acidity 41.3mmolOH/L). Flatness deviations due to the x, y stage mechanical movement were the major contribution to the measurement uncertainty; with maximum Sz flatness errors of 0.49μm. Whereas measurement noise; non-linearity's in x, y, z and enamel sample dimensional instability contributed minimal errors. The measurement errors were propagated into an uncertainty budget following a Type B uncertainty evaluation in order to calculate the Standard Combined Uncertainty (u c ), which was ±0.28μm. Statistically significant increases in the median (IQR) roughness (Sa) of the polished samples occurred after 15 (+0.17 (0.13)μm), 30 (+0.12 (0.09)μm) and 45 (+0.18 (0.15)μm) min of erosion (Pchromatic confocal profilometry was from flatness deviations however by optimizing measurement protocols the profilometer successfully characterized surface texture changes in enamel from erosive wear in vitro. Copyright © 2017 The Academy of Dental Materials. All rights reserved.

In-vitro study investigating influence of toothpaste containing green tea extract on the microhardness of demineralized human enamel

Science.gov (United States)

Febrian, K.; Triaminingsih, S.; Indrani, DJ

2017-08-01

The aim of this study was to analyze the influence of toothpaste containing green tea extract on the microhardness of demineralized enamel. Human tooth, which was demineralised in citric acid solution, had a toothpaste containing green tea extract of concentration of 5, 10 or 15% application. Microhardness measurement was carried out on each enamel surface of the teeth for initial, after the demineralization and after application of the tooth pastes. It showed that there was significant decrease between enamel microhardness of the teeth at the initial condition and after demineralization. After application of the toothpaste containing green tea extract of each concentration the microhardnss increased significantly. However, there the microhardness was insignificant between the applications of each green tea concentration.

An In Vitro Evaluation of Leakage of Two Etch and Rinse and Two Self-Etch Adhesives after Thermocycling

OpenAIRE

Geerts, Sabine; Bolette, Amandine; Seidel, Laurence; Guéders, Audrey

2012-01-01

Our experiment evaluated the microleakage in resin composite restorations bonded to dental tissues with different adhesive systems. 40 class V cavities were prepared on the facial and lingual surfaces of each tooth with coronal margins in enamel and apical margins in cementum (root dentin). The teeth were restored with Z100 resin composite bonded with different adhesive systems: Scotchbond Multipurpose (SBMP), a 3-step Etch and Rinse adhesive, Adper Scotchbond 1 XT (SB1), a 2-step Etch and Ri...

Shear Bond Strength of Three Orthodontic Bonding Systems on Enamel and Restorative Materials

Directory of Open Access Journals (Sweden)

Andreas Hellak

2016-01-01

Full Text Available Objective. The aim of this in vitro study was to determine the shear bond strength (SBS and adhesive remnant index (ARI score of two self-etching no-mix adhesives (iBond™ and Scotchbond™ on different prosthetic surfaces and enamel, in comparison with the commonly used total etch system Transbond XT™. Materials and Methods. A total of 270 surfaces (1 enamel and 8 restorative surfaces, n=30 were randomly divided into three adhesive groups. In group 1 (control brackets were bonded with Transbond XT primer. In the experimental groups iBond adhesive (group 2 and Scotchbond Universal adhesive (group 3 were used. The SBS was measured using a Zwicki 1120™ testing machine. The ARI and SBS were compared statistically using the Kruskal–Wallis test (P≤0.05. Results. Significant differences in SBS and ARI were found between the control group and experimental groups. Conclusions. Transbond XT showed the highest SBS on human enamel. Scotchbond Universal on average provides the best bonding on all other types of surface (metal, composite, and porcelain, with no need for additional primers. It might therefore be helpful for simplifying bonding in orthodontic procedures on restorative materials in patients. If metal brackets have to be bonded to a metal surface, the use of a dual-curing resin is recommended.

Shear Bond Strength of Three Orthodontic Bonding Systems on Enamel and Restorative Materials.

Science.gov (United States)

Hellak, Andreas; Ebeling, Jennifer; Schauseil, Michael; Stein, Steffen; Roggendorf, Matthias; Korbmacher-Steiner, Heike

2016-01-01

Objective. The aim of this in vitro study was to determine the shear bond strength (SBS) and adhesive remnant index (ARI) score of two self-etching no-mix adhesives (iBond ™ and Scotchbond ™ ) on different prosthetic surfaces and enamel, in comparison with the commonly used total etch system Transbond XT ™ . Materials and Methods . A total of 270 surfaces (1 enamel and 8 restorative surfaces, n = 30) were randomly divided into three adhesive groups. In group 1 (control) brackets were bonded with Transbond XT primer. In the experimental groups iBond adhesive (group 2) and Scotchbond Universal adhesive (group 3) were used. The SBS was measured using a Zwicki 1120 ™ testing machine. The ARI and SBS were compared statistically using the Kruskal-Wallis test ( P ≤ 0.05). Results . Significant differences in SBS and ARI were found between the control group and experimental groups. Conclusions . Transbond XT showed the highest SBS on human enamel. Scotchbond Universal on average provides the best bonding on all other types of surface (metal, composite, and porcelain), with no need for additional primers. It might therefore be helpful for simplifying bonding in orthodontic procedures on restorative materials in patients. If metal brackets have to be bonded to a metal surface, the use of a dual-curing resin is recommended.

Type VII collagen is enriched in the enamel organic matrix associated with the dentin-enamel junction of mature human teeth.

Science.gov (United States)

McGuire, Jacob D; Walker, Mary P; Mousa, Ahmad; Wang, Yong; Gorski, Jeff P

2014-06-01

The inner enamel region of erupted teeth is known to exhibit higher fracture toughness and crack growth resistance than bulk phase enamel. However, an explanation for this behavior has been hampered by the lack of compositional information for the residual enamel organic matrix. Since enamel-forming ameloblasts are known to express type VII collagen and type VII collagen null mice display abnormal amelogenesis, the aim of this study was to determine whether type VII collagen is a component of the enamel organic matrix at the dentin-enamel junction (DEJ) of mature human teeth. Immunofluorescent confocal microscopy of demineralized tooth sections localized type VII collagen to the organic matrix surrounding individual enamel rods near the DEJ. Morphologically, immunoreactive type VII collagen helical-bundles resembled the gnarled-pattern of enamel rods detected by Coomassie Blue staining. Western blotting of whole crown or enamel matrix extracts also identified characteristic Mr=280 and 230 kDa type VII dimeric forms, which resolved into 75 and 25 kDa bands upon reduction. As expected, the collagenous domain of type VII collagen was resistant to pepsin digestion, but was susceptible to purified bacterial collagenase. These results demonstrate the inner enamel organic matrix in mature teeth contains macromolecular type VII collagen. Based on its physical association with the DEJ and its well-appreciated capacity to complex with other collagens, we hypothesize that enamel embedded type VII collagen fibrils may contribute not only to the structural resilience of enamel, but may also play a role in bonding enamel to dentin. Copyright © 2014 Elsevier Inc. All rights reserved.

Shear bond strength of one-step self-etch adhesives: pH influence

Science.gov (United States)

Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

2015-01-01

Background: The aim of this study was to compare the shear bond strength of four one-step self-etch adhesives with different pH values to enamel and dentin. Materials and Methods: In this in vitro study, 200 bovine permanent mandibular incisors were used. Four one-step self-etch adhesives with different pH values were tested both on enamel and on dentin: Adper™ Easy Bond Self-Etch Adhesive (pH = 0.8-1), Futurabond NR (pH=2), G-aenial Bond (pH = 1.5), Clearfil S3 Bond (pH = 2.7). After adhesive systems application, a nanohybrid composite resin was inserted into the bonded surface. The specimens were placed in a universal testing machine. The shear bond strength was performed at a cross-head speed of 1 mm/min until the sample rupture. The shear bond strength values (MPa) of the different groups were compared with analysis of variance after that Kolmogorov and Smirnov tests were applied to assess normality of distributions. P enamel shear bond strength, the highest shear bond strength values were reported with Futurabond NR (P adhesive systems showed lower shear bond strength values with significant differences between them (P 0.05). Conclusion: The pH values of adhesive systems did not influence significantly their shear bond strength to enamel or dentin. PMID:26005459

Effectiveness of anchovy substrate application on decreasing acid solubility of Sprague Dawley rats’ tooth enamel (in vivo)

Science.gov (United States)

Triputra, F.; Puspitawati, R.; Gunawan, H. A.

2017-08-01

Anchovies (Stolephorus insularis), a natural resource of Indonesia, contain fluoride in the form of CaF2 and can function as a fluoridation material to prevent dental caries. The aim of this study is to study the effectiveness of anchovy substrate, through food or topical application, in decreasing the acid solubility of tooth enamel. This research used 14 Sprague Dawley rats as subjects divided into the following 5 groups: baseline, experimental feeding, experimental smearing, and their negative controls. After 15 days of anchovy substrate application, lower incisors were extracted and the acid solubility of enamel was analyzed qualitatively and quantitatively using a stereo microscope and a Micro-Vickers Hardness Tester. Analysis of enamel surface destruction and enamel surface microscopic hardness shifting after a 60 sec application of H2PO4 (50% concentration) resulted in a decrease in acid solubility of enamel treated with anchovy substrate. This result can be seen with both the chewing and smearing method. S. insularis can be used as an alternative material for fluoridation.

Torque Analysis of a Triple Acid-Etched Titanium Implant Surface

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Ana Emília Farias Pontes

2015-01-01

Full Text Available The present study aimed to evaluate the removal torque of titanium implants treated with triple acid etching. Twenty-one rats were used in this study. For all animals, the tibia was prepared with a 2 mm drill, and a titanium implant (2 × 4 mm was inserted after treatment using the subtraction method of triple acid etching. The flaps were sutured. Seven animals were killed 14, 28, and 63 days after implant installation, and the load necessary for removing the implant from the bone was evaluated by using a torque meter. The torque values were as follows: 3.3 ± 1.7 Ncm (14 days, 2.2 ± 1.3 Ncm (28 days, and 6.7 ± 1.4 Ncm (63 days. The torque value at the final healing period (63 days was statistically significantly different from that at other time points tested (ANOVA, p=0.0002. This preliminary study revealed that treatment with triple acid etching can create a promising and efficient surface for the process of osseointegration.

Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

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Yasuhiro, Matsuda; Katsushi, Okuyama; Hiroko, Yamamoto; Hisanori, Komatsu; Masashi, Koka; Takahiro, Sato; Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano

2015-04-01

To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials ["MS coats F" (MSF)] and fluoride-free sealing materials ("hybrid coats 2" [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8-4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

3D enamel thickness in Neandertal and modern human permanent canines.

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Buti, Laura; Le Cabec, Adeline; Panetta, Daniele; Tripodi, Maria; Salvadori, Piero A; Hublin, Jean-Jacques; Feeney, Robin N M; Benazzi, Stefano

2017-12-01

Enamel thickness figures prominently in studies of human evolution, particularly for taxonomy, phylogeny, and paleodietary reconstruction. Attention has focused on molar teeth, through the use of advanced imaging technologies and novel protocols. Despite the important results achieved thus far, further work is needed to investigate all tooth classes. We apply a recent approach developed for anterior teeth to investigate the 3D enamel thickness of Neandertal and modern human (MH) canines. In terms of crown size, the values obtained for both upper and lower unworn/slightly worn canines are significantly greater in Neandertals than in Upper Paleolithic and recent MH. The 3D relative enamel thickness (RET) is significantly lower in Neandertals than in MH. Moreover, differences in 3D RET values between the two groups appear to decrease in worn canines beginning from wear stage 3, suggesting that both the pattern and the stage of wear may have important effects on the 3D RET value. Nevertheless, the 3D average enamel thickness (AET) does not differ between the two groups. In both groups, 3D AET and 3D RET indices are greater in upper canines than in lower canines, and overall the enamel is thicker on the occlusal half of the labial aspect of the crown, particularly in MH. By contrast, the few early modern humans investigated show the highest volumes of enamel while for all other components of 3D enamel, thickness this group holds an intermediate position between Neandertals and recent MH. Overall, our study supports the general findings that Neandertals have relatively thinner enamel than MH (as also observed in molars), indicating that unworn/slightly worn canines can be successfully used to discriminate between the two groups. Further studies, however, are needed to understand whether these differences are functionally related or are the result of pleiotropic or genetic drift effects. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Evaluation of microshear bond strength of resin composites to enamel of dental adhesive systems associated with Er,Cr:YSGG laser

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Cassimiro-Silva, Patricia F.; Zezell, Denise M.; Monteiro, Gabriela Q. d. M.; Benetti, Carolina; de Paula Eduardo, Carlos; Gomes, Anderson S. L.

2016-02-01

The aim of this in vitro study was to evaluate the microshear bond strength (μSBS) of resin composite to enamel etching by Er,Cr:YSGG laser with the use of two differents adhesives systems. Fifty freshly extracted human molars halves were embedded in acrylic resin before preparation for the study, making a total of up to 100 available samples. The specimens were randomly assigned into six groups (η=10) according to substrate pre-treatment and adhesive system on the enamel. A two-step self-etching primer system (Clearfil SE Bond) and a universal adhesive used as an etch-andrinse adhesive (Adper Single Bond Universal) were applied to the nonirradiated enamel surface according to manufacturer's instructions, as control groups (Control CF and Control SB, respectively). For the other groups, enamel surfaces were previously irradiated with the Er,Cr:YSGG laser with 0.5 W, 75 mJ and 66 J/cm2 (CF 5 Hz and SB 5 Hz) and 1.25 W, 50 mJ and 44 J/cm2 (CF 15 Hz and SB 15 Hz). Irradiation was performed under air (50%) and water (50%) cooling. An independent t-test was performed to compare the adhesive systems. Mean μSBS ± sd (MPa) for each group was 16.857 +/- 2.61, 17.87 +/- 5.83, 12.23 +/- 2.02, 9.88 +/- 2.26, 15.94 +/- 1.98, 17.62 +/- 2.10, respectively. The control groups and the 50 mJ laser groups showed no statistically significant differences, regardless of the adhesive system used. The results obtained lead us to affirm that the bonding interaction of adhesives to enamel depends not only on the morphological aspects of the dental surface, but also on the characteristics of the adhesive employed and the parameters of the laser.

Influence of Air Abrasion and Sonic Technique on Microtensile Bond Strength of One-Step Self-Etch Adhesive on Human Dentin

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Baraba Anja

2015-01-01

Full Text Available The purpose of this in vitro study was to evaluate the microtensile bond strength of one-step self-etch adhesive to human dentin surface modified with air abrasion and sonic technique and to assess the morphological characteristics of the pretreated dentin surface. The occlusal enamel was removed to obtain a flat dentin surface for thirty-six human molar teeth. The teeth were randomly divided into three experimental groups (n = 12 per group, according to the pretreatment of the dentin: (1 control group, (2 air abrasion group, and (3 sonic preparation group. Microtensile bond strength test was performed on a universal testing machine. Two specimens from each experimental group were subjected to SEM examination. There was no statistically significant difference in bond strength between the three experimental groups (P > 0.05. Mean microtensile bond strength (MPa values were 35.3 ± 12.8 for control group, 35.8 ± 13.5 for air abrasion group, and 37.7 ± 12.0 for sonic preparation group. The use of air abrasion and sonic preparation with one-step self-etch adhesive does not appear to enhance or impair microtensile bond strength in dentin.

Erosive effects of acidic center-filled chewing gum on primary and permanent enamel

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Bolan M

2008-01-01

Full Text Available Background: The higher incidence of dental erosion in children and teenagers possibly reflects a high intake of acidic food and beverages as well as a more frequent diagnosis on this condition. Aim: The aim of this study was to evaluate the erosive potential of acidic filling of chewing gum in primary and permanent enamel. Methods and Materials: Eighty enamel blocks (40 primary and 40 permanent teeth were used and randomly distributed into eight groups. Groups were divided according to types of dental substrates (permanent or primary, frequency of exposure to the acidic substance (2X or 4X/day, and concentration (pure or diluted. Exposure time to the acidic content of the chewing gum was five minutes under agitation, during five days. Results: All groups showed a significant decrease in surface microhardness (P < 0.001. There was neither any significant difference in the frequency of exposure to the acidic content nor to the types of dental substrates. There was a statistically significant difference between D1 (pure, 2X/day and D2 (diluted, 2X/day (P = 0.002, D3 (pure, 4X/day and D4 (diluted, 4X/day (P = 0.009 regarding the concentration, then the diluted acid content was associated with a greater decrease in microhardness. Conclusion: It is concluded that the acidic filling of a chewing gum reduced the microhardness of primary and permanent enamel.

In vitro study of the diode laser effect on artificial demineralized surface of human dental enamel; Estudo in vitro do efeito do laser diodo sobre a superficie de esmalte dental humano desmineralizado artificialmente

Energy Technology Data Exchange (ETDEWEB)

Ebel, Patricia

2003-07-01

In scientific literature there are many reports about fusion and resolidification of dental enamel after laser irradiation and their capability to generate surfaces with increased resistance to demineralization compared to non-irradiated areas. The use of high power diode laser on demineralized surfaces of human dental enamel is presented as a good alternative in caries prevention. The purpose of this study is to investigate the morphological changes produced by the use of one high power diode laser on human dental enamel surface after demineralization treatment with lactic acid, under chosen parameters. Fifteen samples of human dental molars were used and divided in four groups: control - demineralization treatment with lactic acid and no irradiation, and demineralization treatment with lactic acid followed of irradiation with 212,20 mJ/cm{sup 2}, 282,84 mJ/cm{sup 2} and 325,38 mJ/cm{sup 2}, respectively. The samples were irradiated with high power diode laser (808 nm) with a 300 {mu}m diameter fiber optics. Black ink was used on enamel surface to enhance the superficial absorption. The samples were studied by optical microscopy and scanning electron microscopy. Modifications on the enamel surfaces were observed. Such modifications were characterized by melted and re-solidified region of the enamel. According with our results the best parameter was 2.0 W, presenting the most uniform surface. The use of high power diode laser as demonstrated in this study is able to promote melting and re-solidification on human dental enamel. (author)

Spatial distribution of the human enamel fracture toughness with aging.

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Zheng, Qinghua; Xu, Haiping; Song, Fan; Zhang, Lan; Zhou, Xuedong; Shao, Yingfeng; Huang, Dingming

2013-10-01

A better understanding of the fracture toughness (KIC) of human enamel and the changes induced by aging is important for the clinical treatment of teeth cracks and fractures. We conducted microindentation tests and chemical content measurements on molar teeth from "young" (18 ≤ age ≤ 25) and "old" (55 ≤ age) patients. The KIC and the mineral contents (calcium and phosphorus) in the outer, the middle, and the inner enamel layers within the cuspal and the intercuspal regions of the crown were measured through the Vickers toughness test and Energy Dispersive X-Ray Spectroscopy (EDS), respectively. The elastic modulus used for the KIC calculation was measured through atomic force microscope (AFM)-based nanoindentation tests. In the outer enamel layer, two direction-specific values of the KIC were calculated separately (direction I, crack running parallel to the occlusal surface; direction II, perpendicular to direction I). The mean KIC of the outer enamel layer was lower than that of the internal layers (penamel layer, old enamel has a lower KIC, II and higher mineral contents than young enamel (penamel surface becomes more prone to cracks with aging partly due to the reduction in the interprismatic organic matrix observed with the maturation of enamel. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of a Desensitizing Varnish on Microleakage of Two Self-Etch Adhesives

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Anna Saffarpour

2016-08-01

Full Text Available Objectives: The aim of this in-vitro experimental study was to assess the effect of application of a desensitizing varnish on the enamel and dentin marginal seal.Materials and Methods: Seventy-two freshly extracted, intact human premolar teeth were divided into four groups (n=18. Class V cavities (3mm in length, 2mm in width and 2mm in depth were prepared on the buccal surface of each tooth. The following sealing materials were applied in the four groups: One-step Clearfil S3 Bond (S3 self-etch adhesive, two-step Clearfil SE Bond (SE self-etch adhesive, S3 Bond+ VivaSens desensitizing varnish (VS+S3 and Clearfil SE Bond + VivaSens (VS+SE. The cavities on the teeth were then incrementally filled with Z350 light-cure composite. The teeth were stored in distilled water for 24 hours at 37°C, and were then thermocycled for 1000 cycles. Then, all the specimens were prepared for dye penetration test and were immersed in 2% basic fuchsin dye and incubated at 37°C for 24 hours. The teeth were then sectioned buccolingually along the center of restorations with a diamond disk.   Microleakage at the tooth-restoration interface was assessed in the enamel and dentin margins blindly using dye penetration under a stereomicroscope at ×20 magnification.Results: There was significantly greater leakage at the enamel and dentin margins in group VS+SE than in group SE; also, these values were higher in group VS+S3 than in S3.Conclusion: Combined application of desensitizing varnish and self-etch adhesives seems to increase microleakage in composite restorations. Thus, its application is not suggested.

Effect of functional monomers in all-in-one adhesive systems on formation of enamel/dentin acid-base resistant zone.

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Nikaido, Toru; Ichikawa, Chiaki; Li, Na; Takagaki, Tomohiro; Sadr, Alireza; Yoshida, Yasuhiro; Suzuki, Kazuomi; Tagami, Junji

2011-01-01

This study aimed at evaluating the effect of functional monomers in all-in-one adhesive systems on formation of acid-base resistant zone (ABRZ) in enamel and dentin. Experimental adhesive systems containing one of three functional monomers; MDP, 3D-SR and 4-META were applied to enamel or dentin surface and light-cured. A universal resin composite was then placed. The specimens were subjected to a demineralizing solution (pH 4.5) and 5% NaClO for acid-base challenge and then observed by SEM. The ABRZ was clearly observed in both enamel and dentin interfaces. However, enamel ABRZ was thinner than dentin ABRZ in all adhesives. Morphology of the ABRZ was different between enamel and dentin, and also among the adhesives. Funnel-shaped erosion was observed only in the enamel specimen with the 4-META adhesive. The formation of enamel/dentin ABRZ was confirmed in all adhesives, but the morphology was influenced by the functional monomers.

Kinetic model for hydroxyapatite precipitation on human enamel surface by electrolytic deposition

International Nuclear Information System (INIS)

Lei Caixia; Liao Yingmin; Feng Zude

2009-01-01

The electrolytic deposition (ELD) of hydroxyapatite (HAP) coating on human enamel surface for different loading times at varied temperatures (ranging from 37 deg. C to 85 deg. C) and varied current densities (ranging from 0.05 mA cm -2 to 10 mA cm -2 ) was investigated in this study. Thin film x-ray diffraction, Fourier transform infrared and micro-Raman spectra analysis, as well as an environmental scanning electron microscope, were used to characterize the coating. The results showed that only the HAP phase occurred on the enamel surface after ELD experiments. The contents of HAP deposits on the enamel surface linearly changed proportional to the square root of the loading time, which was in good agreement with the kinetic model of ELD of HAP coating based on one-dimensional diffusion. The induction periods were observed on all the regression lines, and the rate of the HAP coating formation on enamel showed a linear relationship with the current density. It was implied that the diffusion process was the rate-determining step in the ELD of the HAP coating on human enamel.

What's new in dentine bonding? Self-etch adhesives.

Science.gov (United States)

Burke, F J Trevor

2004-12-01

Bonding to dentine is an integral part of contemporary restorative dentistry, but early systems were not user-friendly. The introduction of new systems which have a reduced number of steps--the self-etch adhesives--could therefore be an advantage to clinicians, provided that they are as effective as previous adhesives. These new self-etch materials appear to form hybrid layers as did the previous generation of materials. However, there is a need for further clinical research on these new materials. Advantages of self-etch systems include, no need to etch and rinse, reduced post-operative sensitivity and low technique sensitivity. Disadvantages include, the inhibition of set of self- or dual-cure resin materials and the need to roughen untreated enamel surfaces prior to bonding.

Association of dental enamel lead levels with risk factors for environmental exposure.

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Olympio, Kelly Polido Kaneshiro; Naozuka, Juliana; Oliveira, Pedro Vitoriano; Cardoso, Maria Regina Alves; Bechara, Etelvino José Henriques; Günther, Wanda Maria Risso

2010-10-01

To analyze household risk factors associated with high lead levels in surface dental enamel. A cross-sectional study was conducted with 160 Brazilian adolescents aged 1418 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03) and smoking (OR = 1.66; 95% CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

Composition of enamel pellicle from dental erosion patients.

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Carpenter, G; Cotroneo, E; Moazzez, R; Rojas-Serrano, M; Donaldson, N; Austin, R; Zaidel, L; Bartlett, D; Proctor, G

2014-01-01

Oral health is dependent upon a thin mobile film of saliva on soft and hard tissues. Salivary proteins adhere to teeth to form the acquired enamel pellicle which is believed to protect teeth from acid erosion. This study investigated whether patients suffering diet-induced dental erosion had altered enamel pellicles. Thirty patients suffering erosion were compared to healthy age-matched controls. Subjects wore a maxillary splint holding hydroxyapatite and human enamel blocks for 1 h. The acquired enamel pellicle was removed from the blocks and compared to the natural incisor pellicle. Basic Erosive Wear Examination scores confirmed that dental erosion was present in erosion patients and absent from healthy age-matched controls. Erosion patients had half the amount of proteins (BCA assay) within the acquired pellicle forming on splint blocks compared to normal controls (p erosion patients (p erosion patients and healthy controls. In summary, the formation of new acquired pellicles on surfaces was reduced in erosion patients, which may explain their greater susceptibility to acid erosion of teeth. © 2014 S. Karger AG, Basel.

The effect of daily fluoride mouth rinsing on enamel erosive/abrasive wear in situ.

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Stenhagen, K R; Hove, L H; Holme, B; Tveit, A B

2013-01-01

It is not known whether application of fluoride agents on enamel results in lasting resistance to erosive/abrasive wear. We investigated if one daily mouth rinse with sodium fluoride (NaF), stannous fluoride (SnF(2)) or titanium tetrafluoride (TiF(4)) solutions protected enamel against erosive/abrasive wear in situ (a paired, randomised and blind study). Sixteen molars were cut into 4 specimens, each with one amalgam filling (measurement reference surface). Two teeth (2 × 4 specimens) were mounted bilaterally (buccal aspects) on acrylic mandibular appliances and worn for 9 days by 8 volunteers. Every morning, the specimens were brushed manually with water (30 s) extra-orally. Then fluoride solutions (0.4% SnF(2) pH 2.5; 0.15% TiF(4) pH 2.1; 0.2% NaF pH 6.5, all 0.05 M F) were applied (2 min). Three of the specimens from each tooth got different treatment, and the fourth served as control. At midday, the specimens were etched for 2 min in 300 ml fresh 0.01 M hydrochloric acid and rinsed in tap water. This etch procedure was repeated in the afternoon. Topographic measurements were performed by a white-light interferometer. Mean surface loss (±SD) for 16 teeth after 9 days was: SnF(2) 1.8 ± 1.9 µm, TiF(4) 3.1 ± 4.8 µm, NaF 26.3 ± 4.7 µm, control 32.3 ± 4.4 µm. Daily rinse with SnF(2), TiF(4) and NaF resulted in 94, 90 and 18% reduction in enamel erosive/abrasive wear, respectively, compared with control (p < 0.05). The superior protective effect of daily rinse with either stannous or titanium tetrafluoride solutions on erosive/abrasive enamel wear is promising. Copyright © 2012 S. Karger AG, Basel.

Comparison of Knoop and Vickers surface microhardness and transverse microradiography for the study of early caries lesion formation in human and bovine enamel.

Science.gov (United States)

Lippert, F; Lynch, R J M

2014-07-01

The aims of the present laboratory study were twofold: a) to investigate the suitability of Knoop and Vickers surface microhardness (SMH) in comparison to transverse microradiography (TMR) to investigate early enamel caries lesion formation; b) to compare the kinetics of caries lesion initiation and progression between human and bovine enamel. Specimens (90×bovine and 90×human enamel) were divided into six groups (demineralization times of 8/16/24/32/40/48h) of 15 per enamel type and demineralized using a partially saturated lactic acid solution. SMH was measured before and after demineralization and changes in indentation length (ΔIL) calculated. Lesions were characterized using TMR. Data were analyzed (two-way ANOVA) and Pearson correlation coefficients calculated. ΔIL increased with increasing demineralization times but plateaued after 40h, whereas lesion depth (L) and integrated mineral loss (ΔZ) increased almost linearly throughout. No differences between Knoop and Vickers SMH in their ability to measure enamel demineralization were observed as both correlated strongly. Overall, ΔIL correlated strongly with ΔZ and L but only moderately with the degree of surface zone mineralization, whereas ΔZ and L correlated strongly. Bovine demineralized faster than human enamel (all techniques). Lesions in bovine formed faster than in human enamel, although the resulting lesions were almost indistinguishable in their mineral distribution characteristics. Early caries lesion demineralization can be sufficiently studied by SMH, but its limitations on the assessment of the mineral status of more demineralized lesions must be considered. Ideally, complementary techniques to assess changes in both physical and chemical lesion characteristics would be employed. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microshear bond strength of composite resins to enamel and porcelain substrates utilizing unfilled versus filled resins.

Science.gov (United States)

Najafi-Abrandabadi, Ahmad; Najafi-Abrandabadi, Siamak; Ghasemi, Amir; Kotick, Philip G

2014-11-01

Failures such as marginal discoloration and composite chipping are still the problems of tooth-colored restorations on the substrate of enamel and porcelain, which some of these problems are consequently as a result of failures in the bonding layer. Using filled resin has been recently introduced to increase the bond strength of this layer. The aim of this study was to compare the microshear bond strength (μ-SBS) of composite resins to enamel incubated in periods of 24 h and 9 months and porcelain with unfilled resin and flowable composites (filled resin). In this in vitro study, two groups of 75 enamel samples with different storage times (24 h and 9 months) and a group of 75 porcelain samples were used. They were divided into 5 experimental groups of 15 samples in each. Composite cylinders in tygon tubes were bonded on the surface of acid-etched enamel and pretreated porcelain. Wave, Wave MV, Wave HV, Grandioflow and Margin Bond were used as bonding agents. The μ-SBS was measured at the speed of 1.0 mm/min. The bond strengths were analyzed with one-way analysis of variance (ANOVA) test followed by Tukey test. P composites (filled resins) can be used instead of unfilled resins in bonding composite resins to enamel and porcelain substrates.

Wear behavior of human enamel against lithium disilicate glass ceramic and type III gold.

Science.gov (United States)

Lee, Ahreum; Swain, Michael; He, Lihong; Lyons, Karl

2014-12-01

The wear behavior of human enamel that opposes different prosthetic materials is still not clear. The purpose of this in vitro study was to investigate and compare the friction and wear behavior of human tooth enamel that opposes 2 indirect restorative materials: lithium disilicate glass ceramic and Type III gold. Friction-wear tests on human enamel (n=5) that opposes lithium disilicate glass ceramic (n=5) and Type III gold (n=5) were conducted in a ball-on-flat configuration with a reciprocating wear testing apparatus. The wear pairs were subjected to a normal load of 9.8 N, a reciprocating amplitude of approximately 200 μm, and a reciprocating frequency of approximately 1.6 Hz for up to 1100 cycles per test under distilled water lubrication. The frictional force of each cycle was recorded, and the corresponding friction coefficient for different wear pairs was calculated. After wear testing, the wear scars on the enamel specimens were examined under a scanning electron microscope. Type III gold had a significantly lower steady-state friction coefficient (P=.009) and caused less wear damage on enamel than lithium disilicate glass ceramic. Enamel that opposed lithium disilicate glass ceramic exhibited cracks, plow furrows, and surface loss, which indicated abrasive wear as the prominent wear mechanism. In comparison, the enamel wear scar that opposed Type III gold had small patches of gold smear adhered to the surface, which indicated a predominantly adhesive wear mechanism. A lower friction coefficient and better wear resistance were observed when human enamel was opposed by Type III gold than by lithium disilicate glass ceramic in vitro. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Process for etching zirconium metallic objects

International Nuclear Information System (INIS)

Panson, A.J.

1988-01-01

In a process for etching of zirconium metallic articles formed from zirconium or a zirconium alloy, wherein the zirconium metallic article is contacted with an aqueous hydrofluoric acid-nitric acid etching bath having an initial ratio of hydrofluoric acid to nitric acid and an initial concentration of hydrofluoric and nitric acids, the improvement, is described comprising: after etching of zirconium metallic articles in the bath for a period of time such that the etching rate has diminished from an initial rate to a lesser rate, adding hydrofluoric acid and nitric acid to the exhausted bath to adjust the concentration and ratio of hydrofluoric acid to nitric acid therein to a value substantially that of the initial concentration and ratio and thereby regenerate the etching solution without removal of dissolved zirconium therefrom; and etching further zirconium metallic articles in the regenerated etching bath

Kinetic model for hydroxyapatite precipitation on human enamel surface by electrolytic deposition

Energy Technology Data Exchange (ETDEWEB)

Lei Caixia; Liao Yingmin; Feng Zude, E-mail: zdfeng@xmu.edu.c [College of Materials, Xiamen University, Xiamen 361005 (China)

2009-06-15

The electrolytic deposition (ELD) of hydroxyapatite (HAP) coating on human enamel surface for different loading times at varied temperatures (ranging from 37 deg. C to 85 deg. C) and varied current densities (ranging from 0.05 mA cm{sup -2} to 10 mA cm{sup -2}) was investigated in this study. Thin film x-ray diffraction, Fourier transform infrared and micro-Raman spectra analysis, as well as an environmental scanning electron microscope, were used to characterize the coating. The results showed that only the HAP phase occurred on the enamel surface after ELD experiments. The contents of HAP deposits on the enamel surface linearly changed proportional to the square root of the loading time, which was in good agreement with the kinetic model of ELD of HAP coating based on one-dimensional diffusion. The induction periods were observed on all the regression lines, and the rate of the HAP coating formation on enamel showed a linear relationship with the current density. It was implied that the diffusion process was the rate-determining step in the ELD of the HAP coating on human enamel.

Microleakage assessment of one- and two-step self-etch adhesive systems with ‎the low shrinkage composites

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Razieh Hoseinifar

2015-07-01

Full Text Available BACKGROUND AND AIM: Different studies evaluating one-step self-etch (SE adhesive systems show contradictory findings, so the aim of this study was to compare the microleakage of one-step SE adhesive systems and CLEARFIL SE BOND (that serves as the “gold-standard” SE adhesive with low shrinkage composites. METHODS: In this in vitro study, Class V cavities with the occlusal margin in enamel and cervical margin in cementum were prepared on the buccal and lingual surfaces of 36 human premolars and molars (72 cavities. The enamel surfaces of the cavities were etched with 37% phosphoric acid and then the specimens were divided into six groups of 6 (12 cavities and the cavities were restored according bellow: Group 1 (Kalore-GC + G-Bond, Group 2 (Grandio + Futurabond NR, Group 3 (Aelite LS Posterior + All Bond SE, Group 4 (Kalore-GC + CLEARFIL SE BOND, Group 5 (Grandio + CLEARFIL SE BOND, and Group 6 (Aelite LS Posterior + CLEARFIL SE BOND. All the specimens were thermocycled for 2000 cycles (5-55 °C and then placed in 0.5% basic fuchsine dye for 24 hours at 37 °C and finally sectioned and observed under the stereomicroscope. Data were analyzed using Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests at a P 0.050. There were no significant differences in microleakage among two-step and one-step SE adhesive systems on both the occlusal and gingival margins. CONCLUSION: According to this study, two-step SE adhesive system (CLEARFIL SE BOND did not provide better marginal seal than the one-step SE adhesive systems.

Acid Etching as Surface Treatment Method for Luting of Glass-Ceramic Restorations, part 1: Acids, Application Protocol and Etching Effectiveness

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Emilija Barjaktarova-Valjakova

2018-03-01

CONCLUSION: Acid etching of the bonding surface of glass - ceramic restorations is considered as the most effective treatment method that provides a reliable bond with composite cement. Selective removing of the glassy matrix of silicate ceramics results in a micromorphological three-dimensional porous surface that allows micromechanical interlocking of the luting composite.

Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

Energy Technology Data Exchange (ETDEWEB)

Yasuhiro, Matsuda, E-mail: matsuda@den.hokudai.ac.jp [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Katsushi, Okuyama [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Hiroko, Yamamoto [Graduate School of Dentistry, Osaka University (Japan); Hisanori, Komatsu [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan); Masashi, Koka; Takahiro, Sato [Takasaki Advanced Radiation Research Institute, JAEA (Japan); Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano [Department of Restorative Dentistry, Graduate School of Dental Medicine Hokkaido University (Japan)

2015-04-01

To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials [“MS coats F” (MSF)] and fluoride-free sealing materials (“hybrid coats 2” [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8–4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries.

Fluorine uptake into the human enamel surface from fluoride-containing sealing materials during cariogenic pH cycling

International Nuclear Information System (INIS)

Yasuhiro, Matsuda; Katsushi, Okuyama; Hiroko, Yamamoto; Hisanori, Komatsu; Masashi, Koka; Takahiro, Sato; Naoki, Hashimoto; Saiko, Oki; Chiharu, Kawamoto; Hidehiko, Sano

2015-01-01

To prevent the formation of caries and reduce dentin hypersensitivity, sealing materials, either with or without fluoride, are generally applied on the tooth in clinical practice. Application of fluoride-free sealing materials results in the formation of an acid-resistant layer on the tooth surface. On the other hand, fluoride-containing sealing materials might not only form an acid-resistant layer but could possibly further provide fluoride to enhance remineralization and reduce demineralization. In this study, the demineralization prevention ability and fluorine uptake rate in human enamel of fluoride-containing sealing materials [“MS coats F” (MSF)] and fluoride-free sealing materials (“hybrid coats 2” [HI]) were evaluated using an automatic pH cycling system. Each material was applied to the original tooth surface, the cut surfaces were covered with sticky wax, and the automatic pH-cycling system simulated daily acid changes (pH 6.8–4.5) occurring in the oral cavity for 4 weeks. Caries progression was analyzed using transverse microradiography (TMR) taken pre and post the 4 weeks of pH cycling. The fluorine and calcium distributions in the carious lesion in each specimen were evaluated using the proton-induced gamma emission (PIGE) and proton-induced X-ray (PIXE) techniques, respectively. TMR analysis showed that both MSF and HI had a caries-preventing effect after 4 weeks of pH cycling. PIGE/PIXE analysis demonstrated that only MSF resulted in fluoride uptake in the enamel surface. Therefore, MSF can help to form an acid-resistant layer and provide fluoride to the enamel surface. The presence of fluoride on the enamel surface suggested that MSF could prevent demineralization, even if the acid-resistant layer was removed, in clinical settings. The data obtained using the PIGE and PIXE techniques are useful for understanding the benefits of the use of a fluoride-containing sealing material for preventing caries

Enhancement of laser induced damage threshold of fused silica by acid etching combined with UV laser conditioning

International Nuclear Information System (INIS)

Chen Meng; Xiang Xia; Jiang Yong; Zu Xiaotao; Yuan Xiaodong; Zheng Wanguo; Wang Haijun; Li Xibin; Lu Haibing; Jiang Xiaodong; Wang Chengcheng

2010-01-01

Acid etching combined with UV laser conditioning is developed to enhance the laser induced damage threshold (LIDT) of fused silica. Firstly, the fused silica is etched for 1 ∼ 100 min with a buffered 1% HF solution. After acid etching, its transmittance, surface roughness and LIDT are measured. The results reveal that the fused silica has the highest LIDT and transmittance after etching for 10 min. Then UV laser (355 nm) conditioning is adopted to process the 10-min-etched fused silica. When the laser fluence is below 60% of fused silica's zero probability damage threshold, the LIDT increases gradually with the increase of laser conditioning fluence. However, the LIDT rapidly decreases to be lower than the threshold of the 10-min-etched fused silica when the conditioning fluence is up to 80% of the threshold. Proper acid etching and laser conditioning parameters will effectively enhance the laser damage resistance of fused silica. (authors)

Acid demineralization susceptibility of dental enamel submitted to different bleaching techniques and fluoridation regimens.

Science.gov (United States)

Salomão, Dlf; Santos, Dm; Nogueira, Rd; Palma-Dibb, Rg; Geraldo-Martins, Vr

2014-01-01

The aim of the current study was to assess the acid demineralization susceptibility of bleached dental enamel submitted to different fluoride regimens. One hundred bovine enamel blocks (6×6×3 mm) were randomly divided into 10 groups (n=10). Groups 1 and 2 received no bleaching. Groups 3 to 6 were submitted to an at-home bleaching technique using 6% hydrogen peroxide (HP; G3 and G4) or 10% carbamide peroxide (CP; G5 and G6). Groups 7 to 10 were submitted to an in-office bleaching technique using 35% HP (G7 and G8) or 35% CP (G9 and G10). During bleaching, a daily fluoridation regimen of 0.05% sodium fluoride (NaF) solution was performed on groups 3, 5, 7, and 9, while weekly fluoridation with a 2% NaF gel was performed on groups 4, 6, 8, and 10. The samples in groups 2 to 10 were pH cycled for 14 consecutive days. The samples from all groups were then assessed by cross-sectional Knoop microhardness at different depths from the outer enamel surface. The average Knoop hardness numbers (KHNs) were compared using one-way analysis of variance and Tukey tests (α=0.05). The comparison between groups 1 and 2 showed that the demineralization method was effective. The comparison among groups 2 to 6 showed the same susceptibility to acid demineralization, regardless of the fluoridation method used. However, the samples from groups 8 and 10 showed more susceptibility to acid demineralization when compared with group 2 (penamel to acid demineralization. However, the use of 35% HP and 35% CP must be associated with a daily fluoridation regimen, otherwise the in-office bleaching makes the bleached enamel more susceptible to acid demineralization.

Fracture processes and mechanisms of crack growth resistance in human enamel

Science.gov (United States)

Bajaj, Devendra; Park, Saejin; Quinn, George D.; Arola, Dwayne

2010-07-01

Human enamel has a complex micro-structure that varies with distance from the tooth’s outer surface. But contributions from the microstructure to the fracture toughness and the mechanisms of crack growth resistance have not been explored in detail. In this investigation the apparent fracture toughness of human enamel and the mechanisms of crack growth resistance were evaluated using the indentation fracture approach and an incremental crack growth technique. Indentation cracks were introduced on polished surfaces of enamel at selected distances from the occlusal surface. In addition, an incremental crack growth approach using compact tension specimens was used to quantify the crack growth resistance as a Junction of distance from the occlusal surface. There were significant differences in the apparent toughness estimated using the two approaches, which was attributed to the active crack length and corresponding scale of the toughening mechanisms.

Association of dental enamel lead levels with risk factors for environmental exposure

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Kelly Polido Kaneshiro Olympio

2010-10-01

Full Text Available OBJECTIVE: To analyze household risk factors associated with high lead levels in surface dental enamel. METHODS: A cross-sectional study was conducted with 160 Brazilian adolescents aged 14-18 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. RESULTS: The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97; and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00. Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03 and smoking (OR = 1.66; 95% CI: 0.52;5.28 were not found to be associated with high dental enamel lead levels. CONCLUSIONS: Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

Hidden contributions of the enamel rods on the fracture resistance of human teeth.

Science.gov (United States)

Yahyazadehfar, M; Bajaj, Devendra; Arola, Dwayne D

2013-01-01

The enamel of human teeth is generally regarded as a brittle material with low fracture toughness. Consequently, the contributions of this tissue in resisting tooth fracture and the importance of its complex microstructure have been largely overlooked. In this study an experimental evaluation of the crack growth resistance of human enamel was conducted to characterize the role of rod (i.e. prism) orientation and degree of decussation on the fracture behavior of this tissue. Incremental crack growth was achieved in-plane, with the rods in directions longitudinal or transverse to their axes. Results showed that the fracture resistance of enamel is both inhomogeneous and spatially anisotropic. Cracks extending transverse to the rods in the outer enamel undergo a lower rise in toughness with extension, and achieve significantly lower fracture resistance than in the longitudinal direction. Though cracks initiating at the surface of teeth may begin extension towards the dentin-enamel junction, they are deflected by the decussated rods and continue growth about the tooth's periphery, transverse to the rods in the outer enamel. This process facilitates dissipation of fracture energy and averts cracks from extending towards the dentin and vital pulp. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effect of Sodium Ascorbate and Delayed Bonding on the Bond Strength of Silorane and Two-step Self-etch Adhesive Systems in Bleached Enamel

Directory of Open Access Journals (Sweden)

Mehdi Abed Kahnemooyi

2014-12-01

Full Text Available Background and aims. Studies have shown decreased bond strength of composite resin to human and bovine bleached enamel. This study evaluated the effect of sodium ascorbate and delayed bonding on the bond strength of two adhesive systems to bleached enamel. Materials and methods. The labial surfaces of 150 sound bovine incisor teeth were abraded with abrasive paper. The teeth were randomly divided into 8 groups: A: control; B: bleached with 35% hydrogen peroxide; C: bleached with 35% hydrogen peroxide + sodium ascorbate gel; and D: bleached with 35% hydrogen peroxide + delayed bonding. In groups A‒D, silorane adhesive system and Filtek silorane composite resin were used. In groups E‒H, the same preparation methods of groups A‒D were used. Two-step self-etch Clearfil SE Bond adhesive systems and AP-X composite resin were administered. Shear bond strength of each group was measured. Two samples were prepared for each surface preparation for ultrastructural evaluation. Two-way ANOVA and Tukey test were used for data analysis at P<0.05. Results. The interaction between the adhesive system type and surface preparation protocol was significant (P=0.014, with significant differences in shear bond strengths in terms of the adhesive systems (P<0.01. There were significant differences in shear bond strength in terms of surface preparation techniques irrespective of the adhesive system (P<0.01. Conclusion. The results showed that bleaching with 35% hydrogen peroxide decreased the shear bond strength values with both adhesive systems, and a one-week delay in bonding and 10% sodium ascorbate for 10 minutes restored the bond strength in both adhesive systems.

Bond strength of orthodontic light-cured resin-modified glass ionomer cement.

Science.gov (United States)

Cheng, Hsiang Yu; Chen, Chien Hsiu; Li, Chuan Li; Tsai, Hung Huey; Chou, Ta Hsiung; Wang, Wei Nan

2011-04-01

The purpose of this study was to compare the bond strengths and debonded interfaces achieved with light-cured resin-modified glass ionomer cement (RMGIC) and conventional light-cured composite resin. In addition, the effects of acid etching and water contamination were examined. One hundred human premolars were randomly divided into five equal groups. The mini Dyna-lock upper premolar bracket was selected for testing. The first four groups were treated with light-cured RMGIC with or without 15 per cent phosphoric acid-etching treatment and with or without water contamination preceding bracket bonding. The control samples were treated with the conventional light-cured Transbond composite resin under acid etching and without water contamination. Subsequently, the brackets were debonded by tensile force using an Instron machine. The modified adhesive remnant index (ARI) scores were assigned to the bracket base of the debonded interfaces using a scanning electron microscope. The bond strength and modified ARI scores were determined and analysed statistically by one-way analysis of variance and chi-square test. Under all four conditions, the bond strength of the light-cure RMGIC was equal to or higher than that of the conventional composite resin. The highest bond strength was achieved when using RMGIC with acid etching but without water contamination. The modified ARI scores were 2 for Fuji Ortho LC and 3 for Transbond. No enamel detachment was found in any group. Fifteen per cent phosphoric acid etching without moistening the enamel of Fuji Ortho LC provided the more favourable bond strength. Enamel surfaces, with or without water contamination and with or without acid etching, had the same or a greater bond strength than Transbond.

Influence of different pre-etching times on fatigue strength of self-etch adhesives to dentin.

Science.gov (United States)

Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Suzuki, Takayuki; Scheidel, Donal D; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

2016-04-01

The purpose of this study was to use shear bond strength (SBS) and shear fatigue strength (SFS) testing to determine the influence on dentin bonding of phosphoric acid pre-etching times before the application of self-etch adhesives. Two single-step self-etch universal adhesives [Prime & Bond Elect (EL) and Scotchbond Universal (SU)], a conventional single-step self-etch adhesive [G-aenial Bond (GB)], and a two-step self-etch adhesive [OptiBond XTR (OX)] were used. The SBS and SFS values were obtained with phosphoric acid pre-etching times of 3, 10, or 15 s before application of the adhesives, and for a control without pre-etching. For groups with 3 s of pre-etching, SU and EL showed higher SBS values than control groups. No significant difference was observed for GB among the 3 s, 10 s, and control groups, but the 15 s pre-etching group showed significantly lower SBS and SFS values than the control group. No significant difference was found for OX among the pre-etching groups. Reducing phosphoric acid pre-etching time can minimize the adverse effect on dentin bonding durability for the conventional self-etch adhesives. Furthermore, a short phosphoric acid pre-etching time enhances the dentin bonding performance of universal adhesives. © 2016 Eur J Oral Sci.

Effect of surface acid etching on the biaxial flexural strength of two hot-pressed glass ceramics.

Science.gov (United States)

Hooshmand, Tabassom; Parvizi, Shaghayegh; Keshvad, Alireza

2008-07-01

The purpose of this study was to assess the effect of surface acid etching on the biaxial flexural strength of two hot-pressed glass ceramics reinforced by leucite or lithium disilicate crystals. Forty glass ceramic disks (14-mm diameter, 2-mm thick) consisting of 20 leucite-based ceramic disks (IPS Empress) and 20 lithia disilicate-based ceramic (IPS Empress 2) were produced by hot-pressing technique. All specimens were polished and then cleaned ultrasonically in distilled water. Ten specimens of each ceramic group were then etched with 9% hydrofluoric (HF) acid gel for 2 minutes and cleaned ultrasonically again. The biaxial flexural strength was measured by the piston-on-three-ball test in a universal testing machine. Data based on ten specimens in each group were analyzed by two-way ANOVA (alpha= 0.05). Microstructure of ceramic surfaces before and after acid etching was also examined by a scanning electron microscope. The mean biaxial flexural strength values for each group tested were (in MPa): nonetched IPS Empress = 118.6 +/- 25.5; etched IPS Empress = 102.9 +/- 15.4; nonetched IPS Empress 2 = 283.0 +/- 48.5; and etched IPS Empress 2 = 250.6 +/- 34.6. The results showed that the etching process reduced the biaxial flexural strengths significantly for both ceramic types (p= 0.025). No significant interaction between the ceramic type and etching process was found (p= 0.407). From the results, it was concluded that surface HF acid etching could have a weakening effect on hot-pressed leucite or lithia disilicate-based glass ceramic systems.

Testing functional and morphological interpretations of enamel thickness along the deciduous tooth row in human children.

OpenAIRE

Mahoney, Patrick

2013-01-01

The significance of a gradient in enamel thickness along the human permanent molar row has been debated in the literature. Some attribute increased enamel thickness from first to third molars to greater bite force during chewing. Others argue that thicker third molar enamel relates to a smaller crown size facilitated by a reduced dentin component. Thus, differences in morphology, not function, explains enamel thickness. This study draws on these different interpretive models to assess enamel ...

Effect of clearfil protect bond and transbond plus self-etch primer on shear bond strength of orthodontic brackets

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S Hamid Raji

2011-01-01

Conclusion: The shear bond strength of clearfil protect bond and transbond plus self-etch primer was enough for bonding the orthodontic brackets. The mode of failure of bonded brackets with these two self-etch primers is safe for enamel.

Dependencies of the radiation sensitivity of human tooth enamel in EPR dosimetry

International Nuclear Information System (INIS)

Wieser, A.; El-Faramawy, N.; Meckbach, R.

2001-01-01

The EPR dose response of tooth enamel was determined for human molars collected in Egypt. The influence of age, gender and residence of the tooth donors as well as tooth position and sample preparation on EPR sensitivity and its variability over the enamel samples was investigated. The EPR sensitivity and its variability were found to depend only on the sample preparation procedure. The variability in EPR sensitivity of enamel from Egyptian teeth was maximally 10% and the mean sensitivity was in good agreement with that of German teeth

Three-dimensional quantitative analysis of adhesive remnants and enamel loss resulting from debonding orthodontic molar tubes.

Science.gov (United States)

Janiszewska-Olszowska, Joanna; Tandecka, Katarzyna; Szatkiewicz, Tomasz; Sporniak-Tutak, Katarzyna; Grocholewicz, Katarzyna

2014-09-10

Presenting a new method for direct, quantitative analysis of enamel surface. Measurement of adhesive remnants and enamel loss resulting from debonding molar tubes. Buccal surfaces of fifteen extracted human molars were directly scanned with an optic blue-light 3D scanner to the nearest 2 μm. After 20 s etching molar tubes were bonded and after 24 h storing in 0.9% saline - debonded. Then 3D scanning was repeated. Superimposition and comparison were proceeded and shape alterations of the entire objects were analyzed using specialized computer software. Residual adhesive heights as well as enamel loss depths have been obtained for the entire buccal surfaces. Residual adhesive volume and enamel loss volume have been calculated for every tooth. The maximum height of adhesive remaining on enamel surface was 0.76 mm and the volume on particular teeth ranged from 0.047 mm3 to 4.16 mm3. The median adhesive remnant volume was 0.988 mm3. Mean depths of enamel loss for particular teeth ranged from 0.0076 mm to 0.0416 mm. Highest maximum depth of enamel loss was 0.207 mm. Median volume of enamel loss was 0.104 mm3 and maximum volume was 1.484 mm3. Blue-light 3D scanning is able to provide direct precise scans of the enamel surface, which can be superimposed in order to calculate shape alterations. Debonding molar tubes leaves a certain amount of adhesive remnants on the enamel, however the interface fracture pattern varies for particular teeth and areas of enamel loss are present as well.

Evaluation of microtensile bond strength of different fissure sealants to bovine enamel.

Science.gov (United States)

Sen Tunc, E; Bayrak, S; Tuloglu, N; Ertas, E

2012-03-01

The aim of this study was to evaluate the microtensile bond strength (μTBS) of a new fissure sealant and compare it with conventional sealants which are applied to enamel alone, and also with self-etch and etch-and-rinse adhesives. Enamel specimens were prepared and randomly distributed into three groups according to fissure sealant (Aegis, Helioseal F, Helioseal Clear). Each group was then subdivided according to adhesive system (Clearfil S3, Single Bond, no adhesive). A universal testing machine was used to measure μTBS, and data were analysed using one-way ANOVA and Tukey's tests. μTBS values for all Aegis subgroups were significantly lower than for comparable Helioseal F and Helioseal Clear subgroups (p 0.05). In the Helioseal Clear group, μTBS values for Single Bond were significantly higher than for Clearfil S3 (p adhesive subgroups in the Aegis or Helioseal F groups (p > 0.05). Sealant μTBS values may be affected by material content. The addition of an adhesive may improve μTBS values of sealant to enamel. © 2012 Australian Dental Association.

Effect of beverages on bovine dental enamel subjected to erosive challenge with hydrochloric acid.

Science.gov (United States)

Amoras, Dinah Ribeiro; Corona, Silmara Aparecida Milori; Rodrigues, Antonio Luiz; Serra, Mônica Campos

2012-01-01

This study evaluated by an in vitro model the effect of beverages on dental enamel previously subjected to erosive challenge with hydrochloric acid. The factor under study was the type of beverage, in five levels: Sprite® Zero Low-calorie Soda Lime (positive control), Parmalat® ultra high temperature (UHT) milk, Ades® Original soymilk, Leão® Ice Tea Zero ready-to-drink low-calorie peach-flavored black teaand Prata® natural mineral water (negative control). Seventy-five bovine enamel specimens were distributed among the five types of beverages (n=15), according to a randomized complete block design. For the formation of erosive wear lesions, the specimens were immersed in 10 mL aqueous solution of hydrochloric acid 0.01 M for 2 min. Subsequently, the specimens were immersed in 20 mL of the beverages for 1 min, twice daily for 2 days at room temperature. In between, the specimens were kept in 20 mL of artificial saliva at 37ºC. The response variable was the quantitative enamel microhardness. ANOVA and Tukey's test showed highly significant differences (penamel exposed to hydrochloric acid and beverages. The soft drink caused a significantly higher decrease in microhardness compared with the other beverages. The black tea caused a significantly higher reduction in microhardness than the mineral water, UHT milk and soymilk, but lower than the soft drink. Among the analyzed beverages, the soft drink and the black tea caused the most deleterious effects on dental enamel microhardness.

Acid etching and plasma sterilization fail to improve osseointegration of grit blasted titanium implants

DEFF Research Database (Denmark)

Mortensen, Mikkel Saksø; Jakobsen, Stig Storgaard; Saksø, Henrik

2012-01-01

Interaction between implant surface and surrounding bone influences implant fixation. We attempted to improve the bone-implant interaction by 1) adding surface micro scale topography by acid etching, and 2) removing surface-adherent pro-inflammatory agents by plasma cleaning. Implant fixation...... was evaluated by implant osseointegration and biomechanical fixation.The study consisted of two paired animal sub-studies where 10 skeletally mature Labrador dogs were used. Grit blasted titanium alloy implants were inserted press fit in each proximal tibia. In the first study grit blasted implants were...... compared with acid etched grit blasted implants. In the second study grit blasted implants were compared with acid etched grit blasted implants that were further treated with plasma sterilization. Implant performance was evaluated by histomorphometrical investigation (tissue-to-implant contact, peri-implant...

Erosive effects of common beverages on extracted premolar teeth.

Science.gov (United States)

Seow, W K; Thong, K M

2005-09-01

Dental erosion is highly prevalent today, and acidic drinks are thought to be an important cause. The aim of the present investigation was to determine the erosive potential of a range of common beverages on extracted human teeth. The beverages were tested for their individual pHs using a pH meter. The clinical effects of the most erosive beverages were determined by the degree of etching and Vickers microhardness of enamel. The results showed that many common beverages have pHs sufficiently low to cause enamel erosion. Lime juice concentrate (pH 2.1) had the lowest pH, followed by Coca-cola and Pepsi (both with pH 2.3) and Lucozade (pH 2.5). The erosive potential of these beverages was demonstrated by the deep etching of the enamel after five minutes. The Vickers Hardness of enamel was reduced by about 50 per cent in the case of lime juice (p case of Coca-cola (p Coca-cola completely reversed the erosive effects on the enamel. Although only a few of the beverages with the lowest pHs were tested, the present study showed that the most acidic drinks had the greatest erosive effects on enamel. While saliva was protective against erosion, relatively large volumes were required to neutralize the acidity.

Bicarbonate Transport During Enamel Maturation.

Science.gov (United States)

Yin, Kaifeng; Paine, Michael L

2017-11-01

Amelogenesis (tooth enamel formation) is a biomineralization process consisting primarily of two stages (secretory stage and maturation stage) with unique features. During the secretory stage, the inner epithelium of the enamel organ (i.e., the ameloblast cells) synthesizes and secretes enamel matrix proteins (EMPs) into the enamel space. The protein-rich enamel matrix forms a highly organized architecture in a pH-neutral microenvironment. As amelogenesis transitions to maturation stage, EMPs are degraded and internalized by ameloblasts through endosomal-lysosomal pathways. Enamel crystallite formation is initiated early in the secretory stage, however, during maturation stage the more rapid deposition of calcium and phosphate into the enamel space results in a rapid expansion of crystallite length and mineral volume. During maturation-stage amelogenesis, the pH value of enamel varies considerably from slightly above neutral to acidic. Extracellular acid-base balance during enamel maturation is tightly controlled by ameloblast-mediated regulatory networks, which include significant synthesis and movement of bicarbonate ions from both the enamel papillary layer cells and ameloblasts. In this review we summarize the carbonic anhydrases and the carbonate transporters/exchangers involved in pH regulation in maturation-stage amelogenesis. Proteins that have been shown to be instrumental in this process include CA2, CA6, CFTR, AE2, NBCe1, SLC26A1/SAT1, SLC26A3/DRA, SLC26A4/PDS, SLC26A6/PAT1, and SLC26A7/SUT2. In addition, we discuss the association of miRNA regulation with bicarbonate transport in tooth enamel formation.

An investigation on the crack growth resistance of human tooth enamel: Anisotropy, microstructure and toughening

Science.gov (United States)

Yahyazadehfar, Mobin

The enamel of human teeth is generally regarded as a brittle material with low fracture toughness. Consequently, the contributions of this tissue in resisting tooth fracture and the importance of its complex microstructure have been largely overlooked. The primary objective of this dissertation is to characterize the role of enamel's microstructure and degree of decussation on the fracture behavior of human enamel. The importance of the protein content and aging on the fracture toughness of enamel were also explored. Incremental crack growth in sections of human enamel was achieved using a special inset Compact Tension (CT) specimen configuration. Crack extension was achieved in two orthogonal directions, i.e. longitudinal and transverse to the prism axes. Fracture surfaces and the path of crack growth path were evaluated using scanning electron microscopy (SEM) to understand the fundamental mechanisms of crack growth extension. Furthermore, a hybrid approach was adopted to quantify the contribution of toughening mechanisms to the overall toughness. Results of this investigations showed that human enamel exhibits rising R-curve for both directions of crack extension. Cracks extending transverse to the rods in the outer enamel achieved lower rise in toughness with crack extension, and significantly lower toughness (1.23 +/- 0.20 MPa·m 0.5) than in the inner enamel (1.96 +/- 0.28 MPa· 0.5) and in the longitudinal direction (2.01 +/- 0.21 MPa· 0.5). The crack growth resistance exhibited both anisotropy and inhomogeneity, which arise from the complex hierarchical microstructure and the decussated prism structure. Decussation causes deflection of cracks extending from the enamel surface inwards, and facilitates a continuation of transverse crack extension within the outer enamel. This process dissipates fracture energy and averts cracks from extending toward the dentin and vital pulp. This study is the first to investigate the importance of proteins and the effect of

Influence of Surfactants and Fluoride against Enamel Erosion.

Science.gov (United States)

Zanatta, Rayssa Ferreira; Ávila, Daniele Mara da Silva; Miyamoto, Karen Mayumi; Torres, Carlos Rocha Gomes; Borges, Alessandra Bühler

2018-06-06

This study investigated the effect of surfactants associated with sodium fluoride (NaF) on enamel erosion prevention, using an erosion-remineralization in vitro model. Sodium lauryl sulfate (SLS), polysorbate 20 (P20), and cocoamidopropyl betaine (CAPB) were tested, at concentrations of 1.0 and 1.5%, and associated or not with NaF (275 ppm). The control groups were distilled water and the NaF solution. Bovine enamel samples (n = 12) were prepared and submitted to a 5-day cycling model: acid challenge (0.3% citric acid, pH 2.6, 4×/day), human saliva (2 h, 4×/day), and the treatment solutions (2 min, 2×/day). The protective potential of the agents against initial erosion was assessed by microhardness and the surface loss by profilometry. Enamel surface wettability was determined by goniometry, protein adsorption was measured by spectroscopy (FTIR), and the KOH-soluble fluoride was quantified. Goniometry showed that SLS and CAPB increased enamel wettability. No differences were found among the surfactants regarding protein adsorption. Microhardness showed that SLS reduced NaF protection. P20 (1 and 1.5%) and CAPB 1.5% presented a protective effect, but lower than the NaF solution. Profilometry showed that CAPB protected enamel, but no agent associated with NaF promoted a higher protection than the NaF solution alone. KOH-soluble fluoride analysis showed that all surfactants reduced the fluoride adsorption on the enamel surface. Therefore, the surfactants tested (except for P20) changed the enamel surface energy. The SLS decreased the protective potential of NaF on initial erosion, but no tested agent interfered with the protective effect of NaF on enamel erosive wear. © 2018 S. Karger AG, Basel.

In-vivo analysis of fluorine and other elements in human tooth enamel

International Nuclear Information System (INIS)

Baijot-Stroobants, J.; Vreven, J.

1979-01-01

The technique used to study fluorination of human tooth enamel is based on prompt activation by charged particles and detection of the 110- and 197-keV gamma rays emitted in the (p,p'γ) reaction on fluorine. The proton beam is provided by the Van de Graaff accelerator at the University of Namur and is used at atmospheric pressure. The technique can be used for non-destructive determination of fluorine concentrations of the same area of enamel both before and after topical application of fluorinated compounds (commercial solutions and gels) and thus for determination of fluorine fixation in the surface layer of the enamel. A very high degree of enrichment is obtained 30 min after the application of a solution of amine fluoride (AmF; 4400 ppm) and of two fluorophosphate acid (APF) gels (1774 and 3277 ppm). Monofluorophosphate (MFP) and amine fluoride (AmF) gels, however, produce insignificant degrees of enrichment (105 and 228 ppm). Measurement of fluorine retention during the hours after fluorination shows a small loss of fluorine 6 h after application of the AmF solution and the APF gels, whereas with MFP and AmF gels the degree of enrichment is nil 5 h after treatment. Determinations of sodium and of phosphorus have also been carried out with the same technique after brushing with a fluorinated tooth-paste or after topical application of a fluorinated gel. (author)

Study of the arrangement of crystallites in γ-irradiated human enamel by electron paramagnetic resonance

International Nuclear Information System (INIS)

Cevc, P.; Schara, M.; Ravnik, C.; Skaleric, U.

1976-01-01

The arrangement of tooth enamel microcrystals has been studied on CO 3 3- bound electrons by paramagnetic resonance. It was found that noncarious human maxillary central incisors have a greater degree of alignment of tooth enamel microcrystals than the carious ones. The outermost surface layer of enamel showed a greater crystallite degree of alignment than other parts

Microshear Bond Strength of OptiBond All-in-One Self-adhesive Agent to Er:YAG Laser Treated Enamel After Thermocycling and Water Storage.

Science.gov (United States)

Kasraei, Shahin; Yarmohammadi, Ebrahim; Ghazizadeh, Mohammad Vahid

2016-01-01

Introduction: This study aimed to compare the microshear bond strength of composite to enamel treated with Erbium-Doped Yttrium Aluminum Garnet (Er:YAG) laser using a self-etch one step bonding agent. Methods: Seventy-six enamel surfaces were prepared from 38 sound human third molar teeth. Specimens were randomly divided into four groups of 18. The enamel surface in half the specimens was irradiated with Er:YAG laser. One extra specimen from each group was evaluated under a scanning electron microscope (SEM). Composite micro-cylinders were bonded to the specimen surfaces using OptiBond All-In-One (OB) adhesive agent and stored in distilled water for 24 hours. Half the specimens were thermocycled (2000 cycles) and stored in distilled water at 37°C for three months (TW). The microshear bond strength of composite to enamel was measured using a universal testing machine at a crosshead speed of 1 mm/min. The fractured surfaces were evaluated under a stereomicroscope at ×40 magnification to determine the mode of failure. Data were analyzed using repeated measures analysis of variance (ANOVA) and t test. Results: The mean values (±standard deviation) were 17.96 ± 2.92 MPa in OB group, 22.29 ± 4.25 MPa in laser + OB group, 18.11 ± 3.52 MPa in laser + OB + TW group and 9.42 ± 2.47 MPa in OB + TW group. Repeated measures ANOVA showed that laser irradiation increased the microshear bond strength ( P Enamel surface preparation with Er:YAG laser is recommended to enhance the durability of the bond of self-etch bonding systems to enamel.

In vitro demineralization of enamel by orange juice, apple juice, Pepsi Cola and Diet Pepsi Cola.

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Grobler, S R; Senekal, P J; Laubscher, J A

1990-12-01

Enamel demineralization was studied over periods related to normal use of an orange juice, an apple juice, Pepsi Cola and Diet Pepsi Cola. Rectangular blocks of intact human enamel (3 mm x 3 mm) were cut from teeth, coated with nail varnish except for the enamel surface and exposed to the drinks for 2, 4, 5, 6 or 40 minutes. The amount of calcium released from the enamel into solution was determined with the use of an atomic absorption spectrophotometer. The results showed the following degree of enamel demineralization: Pepsi Cola = orange juice greater than apple juice greater than Diet Pepsi Cola. The results suggest that diet colas are less demineralizing than other acid drinks, and complementary plaque studies indicate that they are also less cariogenic. The study emphasized the importance of acid-type, buffer capacity, pH and the presence of other components on the degree of enamel demineralization.

Oriented and Ordered Biomimetic Remineralization of the Surface of Demineralized Dental Enamel Using HAP@ACP Nanoparticles Guided by Glycine

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Wang, Haorong; Xiao, Zuohui; Yang, Jie; Lu, Danyang; Kishen, Anil; Li, Yanqiu; Chen, Zhen; Que, Kehua; Zhang, Qian; Deng, Xuliang; Yang, Xiaoping; Cai, Qing; Chen, Ning; Cong, Changhong; Guan, Binbin; Li, Ting; Zhang, Xu

2017-01-01

Achieving oriented and ordered remineralization on the surface of demineralized dental enamel, thereby restoring the satisfactory mechanical properties approaching those of sound enamel, is still a challenge for dentists. To mimic the natural biomineralization approach for enamel remineralization, the biological process of enamel development proteins, such as amelogenin, was simulated in this study. In this work, carboxymethyl chitosan (CMC) conjugated with alendronate (ALN) was applied to stabilize amorphous calcium phosphate (ACP) to form CMC/ACP nanoparticles. Sodium hypochlorite (NaClO) functioned as the protease which decompose amelogenin in vivo to degrade the CMC-ALN matrix and generate HAP@ACP core-shell nanoparticles. Finally, when guided by 10 mM glycine (Gly), HAP@ACP nanoparticles can arrange orderly and subsequently transform from an amorphous phase to well-ordered rod-like apatite crystals to achieve oriented and ordered biomimetic remineralization on acid-etched enamel surfaces. This biomimetic remineralization process is achieved through the oriented attachment (OA) of nanoparticles based on non-classical crystallization theory. These results indicate that finding and developing analogues of natural proteins such as amelogenin involved in the biomineralization by natural macromolecular polymers and imitating the process of biomineralization would be an effective strategy for enamel remineralization. Furthermore, this method represents a promising method for the management of early caries in minimal invasive dentistry (MID).

Hidden contributions of the enamel rods on the fracture resistance of human teeth

OpenAIRE

Yahyazadehfar, M.; Bajaj, Devendra; Arola, Dwayne D.

2012-01-01

The enamel of human teeth is generally regarded as a brittle material with low fracture toughness. Consequently, the contributions of this tissue in resisting tooth fracture and the importance of its complex microstructure have been largely overlooked. In this study an experimental evaluation of the crack growth resistance of human enamel was conducted to characterize the role of rod (i.e. prism) orientation and degree of decussation on the fracture behavior of this tissue. Incremental crack ...

Threshold value of enamel mineral solubility and dental erosion after consuming acidic soft drinks

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Muhammad Ilyas

2011-09-01

Full Text Available Background: Dental erosion is irreversible and can caused by acidic soft drink consumption. Dental erosion prevention had already been done, but it still has not been satisfying since the consumption of acidic soft drink is still high. There is still no explanation about the threshold value of enamel mineral solubility and the occurance of dental erosion after consuming acidic soft drink. Purpose: This research is aimed to find the threshold value of enamel mineral solubility and dental erosion before and after consuming acidic soft drinks. Methods: Subjects of the research are saliva and enamel of 12 rabbits, which have some criteria such as age > 70 days, body weight > 600 grams, and teeth considered to be healthy. The sample devided equally into 4 groups. Each of those marmooths was given a drink as much as 2.5 cc/consumption (there are 1, 2 and 3× per day by using syringe without injection needle. Salivary minerals then were examined by using atomic absorption spectrophotometric (ASS, while dental erosion was examined using scanning electron microscop (SEM. The data were analyzed by using Paired t-test. Results: It is known that the threshold value of enamel mineral solubility (K, Na, Fe, Mg, Cl, P, Ca, F, C has significant difference (p < 0.05 after being exposed to folic acid. Meanwhile, Fe did not have significant difference (p = 0.090 after being exposed to citric acid. Similarly, C did not have significant difference (p = 0.063 after being exposed to bicarbonate acid. Furthermore, it is also known that the threshold time value of dental erosion are on the 105th day for folic acid, on the 111th day for citric acid, and on the 117th day for bicarbonate acid. Conclusion: Threshold value of enamel mineral solubility before and after consuming soft drinks containing acid is different. Based on the threshold value of dental erosion, it is known that folic acid is the most erosive acid.Latar belakang: Erosi gigi bersifat irreversible

Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers

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Costescu Ruxandra

2009-01-01

Full Text Available Abstract The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The “etch suppression” area is well defined by the illumination spot, a feature that can be used to create heterogeneously etched regions with a high degree of control, shown here on patterned samples. Together with the studied self-limitation effect, the technique offers a way to determine the position of rolled-up micro- and nanotubes independently from the predefined lithographic pattern.

Influence of Nd:YAG laser on the bond strength of self-etching and conventional adhesive systems to dental hard tissues.

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Marimoto, A K; Cunha, L A; Yui, K C K; Huhtala, M F R L; Barcellos, D C; Prakki, A; Gonçalves, S E P

2013-01-01

The aim of this study was to investigate the influence of Nd:YAG laser on the shear bond strength to enamel and dentin of total and self-etch adhesives when the laser was applied over the adhesives, before they were photopolymerized, in an attempt to create a new bonding layer by dentin-adhesive melting. One-hundred twenty bovine incisors were ground to obtain flat surfaces. Specimens were divided into two substrate groups (n=60): substrate E (enamel) and substrate D (dentin). Each substrate group was subdivided into four groups (n=15), according to the surface treatment accomplished: X (Xeno III self-etching adhesive, control), XL (Xeno III + laser Nd:YAG irradiation at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental), S (acid etching + Single Bond conventional adhesive, Control), and SL (acid etching + Single Bond + laser Nd:YAG at 140 mJ/10 Hz for 60 seconds + photopolymerization, experimental). The bonding area was delimited with 3-mm-diameter adhesive tape for the bonding procedures. Cylinders of composite were fabricated on the bonding area using a Teflon matrix. The teeth were stored in water at 37°C/48 h and submitted to shear testing at a crosshead speed of 0.5 mm/min in a universal testing machine. Results were analyzed with three-way analysis of variance (ANOVA; substrate, adhesive, and treatment) and Tukey tests (α=0.05). ANOVA revealed significant differences for the substrate, adhesive system, and type of treatment: lased or unlased (penamel groups were X=20.2 ± 5.61, XL=23.6 ± 4.92, S=20.8 ± 4.55, SL=22.1 ± 5.14 and for the dentin groups were X=14.1 ± 7.51, XL=22.2 ± 6.45, S=11.2 ± 5.77, SL=15.9 ± 3.61. For dentin, Xeno III self-etch adhesive showed significantly higher shear bond strength compared with Single Bond total-etch adhesive; Nd:YAG laser irradiation showed significantly higher shear bond strength compared with control (unlased). Nd:YAG laser application prior to photopolymerization of adhesive systems

Shear bond strength and fracture analysis of human vs. bovine teeth.

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Stefan Rüttermann

Full Text Available PURPOSE: To evaluate if bovine enamel and dentin are appropriate substitutes for the respective human hard tooth tissues to test shear bond strength (SBS and fracture analysis. MATERIALS AND METHODS: 80 sound and caries-free human erupted third molars and 80 freshly extracted bovine permanent central incisors (10 specimens for each group were used to investigate enamel and dentine adhesion of one 2-step self-etch (SE and one 3-step etch and rinse (E&R product. To test SBS the buccal or labial areas were ground plane to obtain appropriate enamel or dentine areas. SE and E&R were applied and SBS was measured prior to and after 500 thermocycles between +5 and +55°C. Fracture analysis was performed for all debonded areas. RESULTS: ANOVA revealed significant differences of enamel and dentin SBS prior to and after thermocycling for both of the adhesives. SBS- of E&R-bonded human enamel increased after thermocycling but SE-bonded did not. Bovine enamel SE-bonded showed higher SBS after TC but E&R-bonded had lower SBS. No differences were found for human dentin SE- or E&R-bonded prior to or after thermocycling but bovine dentin SE-bonded increased whereas bovine dentine E&R-bonded decreased. Considering the totalized and adhesive failures, fracture analysis did not show significances between the adhesives or the respective tooth tissues prior to or after thermocycling. CONCLUSION: Although SBS was different on human and bovine teeth, no differences were found for fracture analysis. This indicates that solely conducted SBS on bovine substrate are not sufficient to judge the perfomance of adhesives, thus bovine teeth are questionnable as a substrate for shear bond testing.

Effects of bleaching agents on human enamel light reflectance.

Science.gov (United States)

Markovic, Ljubisa; Fotouhi, Kasra; Lorenz, Heribert; Jordan, Rainer A; Gaengler, Peter; Zimmer, Stefan

2010-01-01

Tooth whitening has been associated with splitting-up chromogenic molecules by hydrogen peroxides. Though micromorphological alterations are well documented, little is known about optical changes as a function of shifting in wavelengths. Therefore, the aim of the current study was to measure reflectance changes after bleaching in vitro by using a spectrometer. Forty-eight enamel slabs (diameter = 5 mm) were prepared from the sound enamel of extracted human teeth that were: 1) fully impacted, 2) from juveniles ages 10 to 16 years, 3) from adults 35 to 45 years of age and 4) from seniors older than age 65. In all specimens, the baseline total reflectance measurement was performed with a computer-assisted spectrometer (Ocean Optics, Dunedin, FL, USA) within wavelengths (wl) from 430 nm to 800 nm. Four enamel samples of each age group were exposed to either 10% or 15% carbamide peroxide (Illuminé Home, Dentsply, Konstanz, Germany) or 35% hydrogen peroxide (Pola Office, SDI Limited, Victoria, Australia). After surface treatment, all slabs underwent total reflectance measurement again. Statistical analysis was calculated at wl 450, 500 and 750 nm using the Student's paired t-test and one-way variance analysis. Total reflectance significantly increased after bleaching at all enamel maturation stages, irrespective of the bleaching agent concentration, for wl 450 nm (blue) and 500 nm (green) with penamel from adults and seniors (pwhitening of the dental enamel works at different maturation stages, even in impacted teeth. This effect is irrespective of the bleaching protocol used and the bleaching agent concentration.

Enamel biorhythms of humans and great apes: the Havers-Halberg Oscillation hypothesis reconsidered.

Science.gov (United States)

Mahoney, Patrick; Miszkiewicz, Justyna J; Pitfield, Rosie; Deter, Chris; Guatelli-Steinberg, Debbie

2017-02-01

The Havers-Halberg Oscillation (HHO) hypothesis links evidence for the timing of a biorhythm retained in permanent tooth enamel (Retzius periodicity) to adult body mass and life history traits across mammals. Potentially, these links provide a way to access life history of fossil species from teeth. Recently we assessed intra-specific predictions of the HHO on human children. We reported Retzius periodicity (RP) corresponded with enamel thickness, and cusp formation time, when calculated from isolated deciduous teeth. We proposed the biorhythm might not remain constant within an individual. Here, we test our findings. RP is compared between deciduous second and permanent first molars within the maxillae of four human children. Following this, we report the first RPs for deciduous teeth from modern great apes (n = 4), and compare these with new data for permanent teeth (n = 18) from these species, as well as with previously published values. We also explore RP in teeth that retain hypoplastic defects. Results show RP changed within the maxilla of each child, from thinner to thicker enameled molars, and from one side of a hypoplastic defect to the other. When considered alongside correlations between RP and cusp formation time, these observations provide further evidence that RP is associated with enamel growth processes and does not always remain constant within an individual. RP of 5 days for great ape deciduous teeth lay below the lowermost range of those from permanent teeth of modern orangutan and gorilla, and within the lowermost range of RPs from chimpanzee permanent teeth. Our data suggest associations between RP and enamel growth processes of humans might extend to great apes. These findings provide a new framework from which to develop the HHO hypothesis, which can incorporate enamel growth along with other physiological systems. Applications of the HHO to fossil teeth should avoid transferring RP between deciduous and permanent enamel, or including

Determination of fracture toughness of human permanent and primary enamel using an indentation microfracture method.

Science.gov (United States)

Hayashi-Sakai, Sachiko; Sakai, Jun; Sakamoto, Makoto; Endo, Hideaki

2012-09-01

The purpose of the present study was to examine the fracture toughness and Vickers microhardness number of permanent and primary human enamel using the indentation microfracture method. Crack resistance and a parameter indirectly related to fracture toughness were measured in 48 enamel specimens from 16 permanent teeth and 12 enamel specimens obtained from six primary teeth. The Vickers microhardness number of the middle portion was greater than the upper portion in primary enamel. The fracture toughness was highest in the middle portion of permanent enamel, because fracture toughness greatly depends upon microstructure. These findings suggest that primary teeth are not miniature permanent teeth but have specific and characteristic mechanical properties.

Potential of CO2 lasers (10.6 µm associated with fluorides in inhibiting human enamel erosion

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Thayanne Monteiro RAMOS-OLIVEIRA

2014-01-01

Full Text Available This in vitro study aimed to investigate the potential of CO2 lasers associated with different fluoride agents in inhibiting enamel erosion. Human enamel samples were randomly divided into 9 groups (n = 12: G1-eroded enamel; G2-APF gel; G3-AmF/NaF gel; G4-AmF/SnF2 solution; G5-CO2 laser (λ = 10.6 µm+APF gel; G6-CO2 laser+AmF/NaF gel; G7-CO2laser+AmF/SnF2solution; G8-CO2 laser; and G9-sound enamel. The CO2 laser parameters were: 0.45 J/cm2; 6 μs; and 128 Hz. After surface treatment, the samples (except from G9 were immersed in 1% citric acid (pH 4.0, 3 min. Surface microhardness was measured at baseline and after surface softening. The data were statistically analyzed by one-way ANOVA and Tukey’s tests (p < 0.05. G2 (407.6 ± 37.3 presented the highest mean SMH after softening, followed by G3 (407.5 ± 29.8 and G5 (399.7 ± 32.9. Within the fluoride-treated groups, G4 (309.0 ± 24.4 had a significantly lower mean SMH than G3 and G2, which were statistically similar to each other. AmF/NaF and APF application showed potential to protect and control erosion progression in dental enamel, and CO2 laser irradiation at 0.45J/cm2 did not influence its efficacy. CO2 laser irradiation alone under the same conditions could also significantly decrease enamel erosive mineral loss, although at lower levels.

Effect of different surface treatments on adhesion of In-Ceram Zirconia to enamel and dentin substrates.

Science.gov (United States)

Saker, Samah; Ibrahim, Fatma; Ozcan, Mutlu

2013-08-01

Resin bonding of In-Ceram Zirconia (ICZ) ceramics is still a challenge, especially for minimally invasive applications. This study evaluated the adhesion of ICZ to enamel and dentin after different surface treatments of the ceramic. ICZ ceramic specimens (diameter: 6 mm; thickness: 2 mm) (N = 100) were fabricated following the manufacturer's instructions and randomly assigned to 5 groups (n = 20), according to the surface treatment methods applied. The groups were as follows: group C: no treatment; group SB: sandblasting; group SCS-S: CoJet+silane; group SCS-P: CoJet+Alloy Primer; group GE-S: glaze+ hydrofluoric acid etching (9.6%) for 60 s+silane. Each group was randomly divided into two subgroups to be bonded to either enamel or dentin (n = 10 per group) using MDP-based resin cement (Panavia F2.0). All the specimens were subjected to thermocycling (5000x, 5°C-55°C). The specimens were mounted in a universal testing machine and tensile force was applied to the ceramic/cement interface until failure occurred (1 mm/min). After evaluating all the debonded specimens under SEM, the failure types were defined as either "adhesive" with no cement left on the ceramic surface (score 0) or "mixed" with less than 1/2 of the cement left adhered to the surface with no cohesive failure of the substrate (score 1). The data were statistically evaluated using 2-way ANOVA and Tukey's tests (α = 0.05). The highest tensile bond strength for the enamel surfaces was obtained in group GE-S (18.1 ± 2 MPa) and the lowest in group SB (7.1 ± 1.4 MPa). Regarding dentin, group CSC-P showed the highest (12 ± 1.3 MPa) and SB the lowest tensile bond strength (5.7 ± 0.4 MPa). Groups SB, CSC-S, CSC-P, and GE-S did not show significant differences between the different surface treatments on either enamel or dentin surfaces (p enamel and dentin substrates (p enamel substrates, exclusively adhesive failures from ICZ (score 0) were found, on dentin exclusively mixed failures were observed (score

Ceramic-like wear behaviour of human dental enamel.

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Arsecularatne, J A; Hoffman, M

2012-04-01

This paper reports a transmission electron microscopy (TEM) analysis of subsurfaces of enamel specimens following in vitro reciprocating wear tests with an enamel cusp sliding on a flat enamel specimen under hydrated conditions. The obtained results show that crack formation occurred in the wear scar subsurface. The path followed by these cracks seems to be dictated either by the histological structure of enamel or by the contact stress field. Moreover, the analysis of a set of enamel wear results obtained from the literature and application of fracture-based models, originally developed for ceramics, correlate well, confirming the similar wear processes taking place in these materials. This analysis also reveals a marked influence of coefficient of friction on the enamel wear rate: for a higher coefficient of friction value, enamel wear can be severe even under forces generated during normal operation of teeth. Copyright © 2011 Elsevier Ltd. All rights reserved.

Liquid droplet sensing using twisted optical fiber couplers fabricated by hydrofluoric acid flow etching

Science.gov (United States)

Son, Gyeongho; Jung, Youngho; Yu, Kyoungsik

2017-04-01

We report a directional-coupler-based refractive index sensor and its cost-effective fabrication method using hydrofluoric acid droplet wet-etching and surface-tension-driven liquid flows. The proposed fiber sensor consists of a pair of twisted tapered optical fibers with low excess losses. The fiber cores in the etched microfiber region are exposed to the surrounding medium for efficient interaction with the guided light. We observe that the etching-based low-loss fiber-optic sensors can measure the water droplet volume by detecting the refractive index changes of the surrounding medium around the etched fiber core region.

Dental Enamel Development: Proteinases and Their Enamel Matrix Substrates

Science.gov (United States)

Bartlett, John D.

2013-01-01

This review focuses on recent discoveries and delves in detail about what is known about each of the proteins (amelogenin, ameloblastin, and enamelin) and proteinases (matrix metalloproteinase-20 and kallikrein-related peptidase-4) that are secreted into the enamel matrix. After an overview of enamel development, this review focuses on these enamel proteins by describing their nomenclature, tissue expression, functions, proteinase activation, and proteinase substrate specificity. These proteins and their respective null mice and human mutations are also evaluated to shed light on the mechanisms that cause nonsyndromic enamel malformations termed amelogenesis imperfecta. Pertinent controversies are addressed. For example, do any of these proteins have a critical function in addition to their role in enamel development? Does amelogenin initiate crystallite growth, does it inhibit crystallite growth in width and thickness, or does it do neither? Detailed examination of the null mouse literature provides unmistakable clues and/or answers to these questions, and this data is thoroughly analyzed. Striking conclusions from this analysis reveal that widely held paradigms of enamel formation are inadequate. The final section of this review weaves the recent data into a plausible new mechanism by which these enamel matrix proteins support and promote enamel development. PMID:24159389

Evaluation of the bleached human enamel by Scanning Electron Microscopy

DEFF Research Database (Denmark)

Miranda, Carolina Baptista; Pagani, Clovis; Benetti, Ana Raquel

2005-01-01

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......: 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...... 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...