Showing papers in "Operative Dentistry in 2006"
TL;DR: A review of existing literature that covers the engineering of enamel, dentin and pulp, as well on the entire teeth can be found in this paper, where the authors discuss the major roadblocks to overcome before such strategies move to the clinic and are used regularly to treat patients.
Abstract: For many years, operative dentistry has been using regenerative approaches to treat dental disease. The use of calcium hydroxide to stimulate reparative or reactionary dentin is clearly an example of such a therapeutic strategy. The advent of tissue engineering is allowing dentistry to move forward in the use of regeneration as an underlying principle for the treatment of dental disease. Tissue engineering is a multi-disciplinary science that brings together biology, engineering and clinical sciences with developing new tissues and organs. It is based on fundamental principles that involve the identification of appropriate cells, the development of conducive scaffolds and an understanding of the morphogenic signals required to induce cells to regenerate the tissues that were lost. This review is focused on the presentation and discussion of existing literature that covers the engineering of enamel, dentin and pulp, as well on the engineering of entire teeth. There are clearly major road-blocks to overcome before such strategies move to the clinic and are used regularly to treat patients. However, existing evidence strongly suggests that the engineering of new dental structures to replace tissues lost during the process of caries or trauma will have a place in the future of operative dentistry.
568 citations
TL;DR: Results for the degree of conversion measurements show that there is a significant difference in the case of illumination of resin composite samples with LED at the surface and 2 mm depth and for polymerization shrinkage, lower values after 40 seconds were obtained using LED compared to QTH.
Abstract: Clinical Relevance The use of a low intensity light source for photopolymerization based on LED technology provides equivalent final degree conversion with possible flow of the resin composite, similar to when QTH technology is used. At the same time, the lower temperature rise in the sample and the more favorable development of shrinkage kinetics compared to the higher intensities of halogen light may aid in maintaining marginal adaptation while avoiding possible thermal injury.
160 citations
TL;DR: Within the limitations of this study, post systems, where the elastic modulus of the post is similar to that of dentin and core, have a better biomechanical performance.
Abstract: Clinical Relevance When restoring teeth, a higher restoring success rate can be achieved by using posts with an elastic modulus similar to that of dentin and a core, with equal or higher strength, ...
148 citations
TL;DR: It was concluded that two different surface conditioning methods and storage conditions did not significantly affect the bonding properties of Panavia F and RelyX Unicem resin composite luting cements to Zirconia.
Abstract: Clinical Relevance The results of this in vitro study suggest that, in combination with air-particle abrasion methods, Panavia F and RelyX Unicem resin composite luting cements with phosphoric-acid...
123 citations
TL;DR: The roughness parameter (Ra) showed that some of the commercial intraoral polishing kits tested achieved a finish equal in smoothness to the glazed surface, and no correlation was found between the parameter Ry, measured with the profilometer, and AFM.
Abstract: Clinical Relevance Ceramic restorations often require intraoral adjustment and the use of a polishing kit is mandatory to re-establish surface smoothness. When the ceramic surface was ground and po...
120 citations
TL;DR: Overall, the microfilled composites had lower strength than the other composites except Renamel for CS, while Estelite and Supreme had the lowest PS among the materials tested.
Abstract: This study compared the mechanical properties, generalized wear resistance and polymerization shrinkage of a resin composite filled with spherical inorganic filler to other commercial resin composites. Six dental resin composites were tested, including a submicron filled composite (Estelite sigma, Estelite), 1 nano-composite (Filtek Supreme, Supreme), 2 microfilled composites (Heliomolar; Renamel Microfill, Renamel) and 2 microhybrid composites (Esthet X Improved; Tetric Ceram). Compressive strength (CS), diametral tensile strength (DTS), flexural strength (FS), flexural modulus (FM), generalized wear resistance (WV) and polymerization shrinkage (PS) were evaluated for the 6 materials. The specimens were cured according to the manufacturers' instructions in appropriate molds, stored (37 degrees C water, 24 hours), then tested on an Instron testing machine (0.5 mm/minute). PS was tested according to the Archimedes method at 1, 24 and 48 hours continually after polymerization. Data were analyzed by analysis of variance. The results showed that CS values ranged from 252 to 298 MPa, DTS ranged from 35 to 54 MPa, FS from 73 to 140 MPa, FM from 4.8 to 11.1 GPa, WV from 0.037 to 0.086 mm(3) and PS at 24 hours from 2.17 to 3.96 vol%. Composite had statistically significant influence on the in vitro properties tested. Estelite performed similarly to nano-composite and microhybrid composites in mechanical properties and generalized wear resistance, while Estelite and Supreme had the lowest PS among the materials tested. The 2 microhybrid materials had similar properties, while the 2 microfilled composites were different for most properties tested. Overall, the microfilled composites had lower strength than the other composites except Renamel for CS. All the materials had a similar shrinkage pattern in that about 99% of shrinkage occurred in less than 24 hours.
109 citations
TL;DR: Class II cavities were prepared in extracted lower molars filled and cured in three 2-mm increments using a metal matrix, and Spectrum TPH composite was the only composite showing a satisfactory degree of polymerization for all three curing times and both LCUs.
Abstract: Class II cavities were prepared in extracted lower molars filled and cured in three 2-mm increments using a metal matrix. Three composites (Spectrum TPH A4, Ceram X mono M7 and Tetric Ceram A4) were cured with both the SmartLite PS LED LCU and the Spectrum 800 continuous cure halogen LCU using curing cycles of 10, 20 and 40 seconds. Each increment was cured before adding the next. After a seven-day incubation period, the composite specimens were removed from the teeth, embedded in self-curing resin and ground to half the orofacial width. Knoop microhardness was determined 100, 200, 500, 1000, 1500, 2500, 3500, 4500 and 5500 microm from the occlusal surface at a distance of 150 microm and 1000 microm from the metal matrix. The total degree of polymerization of a composite specimen for any given curing time and curing light was determined by calculating the area under the hardness curve. Hardness values 150 microm from the metal matrix never reached maximum values and were generally lower than those 1000 microm from the matrix. The hardest composite was usually encountered between 200 microm and 1000 microm from the occlusal surface. For every composite-curing time combination, there was an increase in microhardness at the top of each increment (measurements at 500, 2500 and 4500 microm) and a decrease towards the bottom of each increment (measurements at 1500, 3500 and 5500 microm). Longer curing times were usually combined with harder composite samples. Spectrum TPH composite was the only composite showing a satisfactory degree of polymerization for all three curing times and both LCUs. Multiple linear regression showed that only the curing time (p < 0.001) and composite material (p < 0.001) had a significant association with the degree of polymerization. The degree of polymerization achieved by the LED LCU was not significantly different from that achieved by the halogen LCU (p = 0.54).
107 citations
TL;DR: Bond strengths were significantly increased following hydrogel and solution of sodium ascorbate treatments (p<0.05), and there was no significant difference among the different forms of Sodium ascorBate preparations.
Abstract: Compromised bonding to bleached enamel can be reversed with sodium ascorbate as an antioxidant. This study evaluated the effect of hydrogel and solution of sodium ascorbate on enamel-resin composite shear bond strength after bleaching. Sixty buccal enamel surfaces obtained from human, sound third molars were randomly divided into 4 groups (n=15). Enamel surfaces were subjected to different treatments: 1) bleaching (10% carbamide peroxide gel); 2) bleaching + 10% sodium ascorbate solution; 3) bleaching + 10% sodium ascorbate hydrogel and 4) bleaching + 20% sodium ascorbate hydrogel. The specimens were bonded with Single Bond and restored with a composite. The specimens were prepared for shear bond testing. The data was evaluated using ANOVA and Tukey tests. Bond strengths were significantly increased following hydrogel and solution of sodium ascorbate treatments (p<0.05). Also, there was no significant difference among the different forms of sodium ascorbate preparations.
95 citations
TL;DR: This study compared the microleakage of an experimental low-shrinkage resin composite, a nanofilled resin composite material (Filtek Supreme) and a hybrid resin composite (Tetric Ceram) using a dye penetration method to find out if it affects incrementally placed restorations.
Abstract: Clinical Relevance Incremental placement remains the preferred restorative technique for direct composites. To reduce the effects of polymerization shrinkage on marginal quality, the low-shrink Hermes system might become a good alternative in clinical practice.
94 citations
TL;DR: Qualitative comparisons of resin tags present in the bleached and unbleached specimens using scanning electron microscopy (SEM) revealed few, thin and fragmented resin tags when 38% hydrogen peroxide and 10% carbamide peroxide were used.
Abstract: This research sought to determine the shear bond strength, degree of resin infiltration and failure mode when organic solvent-based adhesives (acetone or ethanol) were used in immediate bonding to enamel bleached with 10% carbamide peroxide or 38% hydrogen peroxide systems. Seventy-two non-carious bovine incisors were randomly assigned to three groups of 24 specimens each-control group (deionized water), 38% hydrogen peroxide bleach group and 10% carbamide peroxide bleach group. Each group was further subdivided into two subgroups of 12 specimens each according to the adhesive system used to bond the resin composite to enamel surfaces. The two adhesive systems used were Single Bond, an ethanol-based adhesive, and One Step, an acetone-based adhesive. The shear bond strengths of 38% hydrogen peroxide and 10% carbamide peroxide were significantly lower compared to the non-bleached controls. Fractography revealed an adhesive failure mode in all specimens. Qualitative comparisons of resin tags present in the bleached and unbleached specimens using scanning electron microscopy (SEM) revealed few, thin and fragmented resin tags when 38% hydrogen peroxide and 10% carbamide peroxide were used.
92 citations
TL;DR: It can be concluded that the penetration of adhesives into initial lesions inhibited a further demineralization in vitro.
Abstract: This study compared the progression of sealed initial enamel lesions penetrated with a fissure sealant (Helioseal, Vivadent) or various adhesives (Heliobond, Excite, Vivadent; Resulcin, Merz; Solobond M, Voco; Prompt L-Pop, 3M-ESPE) after exposure to a demineralizing solution, in vitro. From 27 bovine teeth, 54 enamel specimens were prepared and covered with nail varnish (control), thus obtaining three windows for treatment. After demineralization (pH 5.0; 14 days), two of the windows (A, B) were etched with phosphoric acid (20%; 5 seconds); whereas, the third area served as the control (C). The specimens were divided randomly into six groups (n=9), and the material was applied (90 seconds) either once (A) or twice (B). Light-curing followed each application. Half of the area of each specimen window was then covered with nail varnish, and the samples were again stored in the demineralizing solution (pH 5.0; 14 days). The specimens were cut perpendicular to the surface, and both enamel slabs were studied after infiltration using a fluorescent, low viscous resin (VIRIN) and confocal microscopy (CLSM). Lesion depths were calculated (ImageJ) from the surface to that point in the lesion where the grey values clearly changed to a darker grey. After demineralization, mean lesion depths (SD) (14 days) were measured at 105 (21) microm. The second demineralization led to a mean progression of the lesion depths of 52 (31)%. Adper Prompt L-Pop and Solobond M could not significantly prevent lesion progression after a single application (p > 0.05; t-test); however, the second application of Solobond M significantly decreased lesion progression (p < 0.05; t-test). Helioseal, Heliobond, Resulcin Monobond and Excite showed significantly better inhibition of the demineralization compared to the other materials (p < 0.05; Bonferroni). It can be concluded that the penetration of adhesives into initial lesions inhibited a further demineralization in vitro.
TL;DR: This study compared the temperature increase in a pulp chamber as a result of using various light-curing units during resin composite polymerization, and it determined the effect of remaining dentin thickness on temperature rise.
Abstract: Clinical Relevance The thickness of the residual dentin is a critical factor in the reducing thermal transfer to pulp, and this transfer varies with the curing unit used.
TL;DR: After 5 years of evaluation, the clinical performance of resin modified glass ionomer restorations was superior to resin composite restorative in non-carious cervical lesions.
Abstract: Clinical Relevance A long-term evaluation of the materials' behavior is relevant for Class V restorations in which clinical performance is particularly challenging.
TL;DR: The results showed that increasing ceramic disc thickness had a negative effect on the curing depth and hardness of all light curing units, with hardness decreasing dramatically under the 2-mm thick discs using LuxOmax, e-Light or Aurys.
Abstract: This study compared the ability of a variety of light sources and exposure modes to polymerize a dual-cured resin composite through ceramic discs of different thicknesses by depth of cure and Vickers microhardness (VHN). Ceramic specimens (360) (Empress 2 [Ivoclar Vivadent], color 300, diameter 4 mm, height 1 or 2 mm) were prepared and inserted into steel molds according to ISO 4049, after which a dual-cured composite resin luting material (Variolink II [Ivoclar Vivadent]) with and without self-curing catalyst was placed. The light curing units used were either a conventional halogen curing unit (Elipar TriLight [3M/ESPE] for 40 seconds), a high-power halogen curing unit (Astralis 10 [Ivoclar Vivadent] for 20 seconds), a plasma arc curing unit (Aurys [Degre K] for 10 seconds or 20 seconds) or different light emitting diode (LED) curing units (Elipar FreeLight I [3M/ESPE] for 40 seconds, Elipar FreeLight II [3M/ESPE] for 20 seconds, LuxOmax [Akeda] for 40 seconds, e-Light [GC] for 12 seconds or 40 seconds). Depth of cure under the ceramic discs was assessed according to ISO 4049, and VHN at 0.5 and 1.0 mm distance from the ceramic disc bottom was determined (ISO 6507-1). Medians and the 25th and 75th percentiles were determined for each group (n=10), and statistical analysis was performed using the Mann-Whitney-U-test (p < or = 0.05). The results showed that increasing ceramic disc thickness had a negative effect on the curing depth and hardness of all light curing units, with hardness decreasing dramatically under the 2-mm thick discs using LuxOmax, e-Light (12 seconds) or Aurys (10 seconds or 20 seconds). The use of a self-curing catalyst is recommended over the light-curable portion only, because it produced an equivalent or greater hardness and depth of cure with all light polymerization modes.
TL;DR: Though microTBS decreased significantly, Clearfil SE, as a 2-step self-etch adhesive, was the only simplified adhesive to perform reliably after 1-year direct water exposure, and the second hypothesis concluded that the 3-step etch-and-rinse adhesive must still be regarded the "gold standard."
Abstract: Clinical Relevance Recently developed “user-friendly” adhesives do not perform as well as traditional 3-step etch-and-rinse adhesives in the long term.
TL;DR: Though the bond strengths to primary Tooth dentin were lower than to permanent tooth dentin, excellent adaptation of the single-step self-etch systems to both dentin substrates was observed and further studies are required to determine the long-term clinical performance of these adhesive systems when applied to primary tooth Dentin.
Abstract: Currently, there is little information regarding the bonding efficacy of single-step self-etch systems to primary tooth dentin. This study examined the microtensile bond strength of single-step self-etch systems (Clearfil tri-S Bond and One-Up Bond F Plus) to sound primary and permanent tooth dentin. Adhesives were applied to flat samples of primary and permanent tooth dentin, and resin composites were bonded according to the manufacturers' instructions. After 24 hours of storage in distilled water at 37 degrees C, hour glass-shaped specimens were produced. They were subjected to microtensile testing at a crosshead speed of 1.0 mm/minute. The results were analyzed using 2-way analysis of variance (ANOVA) followed by the Tukey HSD post-hoc test (alpha=0.05). Field-emission scanning electron microscopy (FE-SEM) observations of the adhesive-treated dentin surfaces and the resin/dentin interface were also conducted. The bond strengths of primary tooth dentin were significantly lower than that of permanent tooth dentin for both self-etch systems: 44.7 +/- 10.4 versus 54.3 +/- 9.0 MPa for Clearfil tri-S Bond and 40.6 +/- 9.9 versus 50.0 +/- 8.7 MPa for One-Up Bond F Plus (p<0.001). There was no statistically significant interaction between the type of adhesive system and the dentin substrate (p=0.957). Although there was no statistically significant difference in the mean values among the different adhesive systems (p=0.094), there was a statistically significant difference in mean values among the different dentin substrates (p<0.001), which were lower for primary tooth dentin than for permanent tooth dentin. The failure modes were also independent of the type of dentin but dependent on the adhesive systems, an equal distribution among the 3 types of failure for Clearfil tri-S Bond and cohesive failures in adhesives for One-Up Bond F Plus. FE-SEM observations of dentin to which adhesive had been applied revealed that the smear layer had been removed and the collagen fibers exposed. Though the bond strengths to primary tooth dentin were lower than to permanent tooth dentin, excellent adaptation of the single-step self-etch systems to both dentin substrates was observed by FE-SEM. Further studies are required to determine the long-term clinical performance of these adhesive systems when applied to primary tooth dentin.
TL;DR: After 1 year, the nanofilled resin composite showed similar performance to the other packable and microhybrid resin composites, whereas at baseline, the materials showed only minor modifications.
Abstract: Clinical Relevance Nanofilled resin composite showed excellent clinical performance, similar to microhybrid and packable composites after 12-months.
TL;DR: It was concluded that bleaching with 38% hydrogen peroxide and 15% carbamide peroxide did not cause major surface texture changes on the polished surfaces of the restorative materials.
Abstract: Clinical Relevance In-office and home bleaching agents do not cause changes that would demand replacement of the restorations when the agents are applied on the polished surfaces of aesthetic denta...
TL;DR: It is suggested that the monomer of Clearfil SE Bond penetrated deeper than previously reported, creating a so-called "hybrid layer," however, its physical properties depended on the condition of the dentin.
Abstract: Clinical Relevance A self-etching primer adhesive system, Clearfil SE Bond, may be able to prevent secondary caries around composite restorations in which an acid-base resistant zone was observed beneath the hybrid layer after acid-base challenge.
TL;DR: This study evaluated the effect of saliva contamination and decontamination methods on the dentin bond strength of one-step self-etching adhesive systems and found that the A1 subgroup showed the greatest decrease in bond strength as compared to the control (p<0.05).
Abstract: Clinical Relevance Saliva contamination significantly affects the bond strength of one-step self-etching adhesive systems to dentin; therefore, saliva contamination must be avoided when using these...
TL;DR: The stress distribution on an endodontically treated maxillary central incisor restored with different post-and-core systems by using a three-dimensional finite element analysis model found the greatest stresses were observed in the coronal third of the roots on facial surfaces.
Abstract: Clinical Relevance According to FEA analysis, under a simulated occlusal load, the cervical area of endodontically treated and crowned maxillary central incisors was the most stress concentrated area. Zirconia ceramic posts create slightly less dentinal stress concentration than titanium and glass-fiber posts.
TL;DR: The microtensile bond strength evaluation was performed after 48 hours of water storage, using untrimmed beams approximately 0.9 mm2 in cross-sectional area at a crosshead speed of 0.6 mm/minute.
Abstract: Clinical Relevance Bond strength to ground enamel of single component self-etching adhesive systems was lower than that of etch-and-rinse and self-etching primer systems.
TL;DR: When using Etch&Prime 3.0, bond structures did not withstand mechanical loading, which may have an influence on the long-term success of restorations and if dentin is acid-etched, alcohol-based adhesive systems showed higher bond strength after mechanical loading.
Abstract: Clinical Relevance Resin-dentin bonds, which may have an influence on the long-term success of restorations, are prone to deterioration after cyclic loading. The tested one-step self-etching system (Etch&Prime 3.0) provided the least reliable dentin adhesion. After acid etching of dentin, alcohol/based adhesives performed better than those containing acetone as solvent.
TL;DR: In conclusion, SBAS should be avoided for vital pulp therapy, while CH remains the capping agent of choice for mechanically exposed human dental pulp.
Abstract: SUMMARY This study evaluated the pulpal response in human dental pulp to direct pulp capping with the Single Bond Adhesive System (SBAS) after 10% or 37% phosphoric acid etching and after capping with Calcium Hydroxide (CH). The degree of bleeding and hemostasis conditions was considered during the adhesive technique. The pulps of 78 sound premolars were capped with SBAS after 37% phosphoric acid etching (Group I) or 10% phosphoric acid etching (Group II) and CH (Group III-control). The cavities were restored with a resin composite (Charisma). After 1, 3, 7 and 30 days, the teeth were extracted and processed for light microscopical examination (H/E, AgNOR silver stain and Brown-Brenn). The patients were followed for postoperative symptomatology evaluation. Clinical results showed the possibility of hemostasis with saline solution only. There was no statistical difference between bleeding generated by 10% and 37% acid solutions. In some cases, contact of the pulp tissue with SASB started the bleeding proce...
TL;DR: Defective restorations that have a Bravo rating for clinical characteristics other than marginal integrity and anatomical form do not need to be immediately replaced.
Abstract: Clinical Relevance Repair offers the most conservative and predictable results for the treatment of amalgam restorations with inadequate marginal adaptation and anatomic form.
TL;DR: The higher the amount of thermal/mechanical cycles, the greater the number of mixed failures and the lower the percentage of adhesive failures.
Abstract: This study evaluated the influence of different thermal (TC) and mechanical (MC) cycling protocols on microtensile bond strength (muTBS) to cervical dentin margins of Class II restorations using two total-etch (TE) adhesives and one self-etching (SE) primer. Class II slot cavities were prepared on the mesial surfaces of 168 bovine incisors and were divided into three groups according to the bonding system used: Single Bond, OptiBond Solo Plus and Clearfil SE Bond. All cavities were restored with Filtek Z250 composite. Following restorative procedures, the restored teeth were allocated to seven subgroups (n = 8) according to the thermal/mechanical protocol performed: G1-control (no cycling), G2-100,000 MC, G3-200,000 MC, G4-500,000 MC, G5-100,000 MC+1,000 TC, G6-200,000 MC+1,000 TC, G7-500,000 MC+1,000 TC. TC was performed using 5 +/- 2 degrees C and 55 +/- 2 degrees C baths, with a dwell time of 60 seconds in each bath. MC was achieved with an axial force of 80 N at 2 cycles/second. The restorations were sectioned perpendicular to the cervical bonded interface into two 0.8-1-mm thick slabs. The slabs were trimmed at the interface to obtain a cross-sectional surface area of 0.8-1 mm2. All specimens were then subjected to muTBS (v = 0.5 mm/minute). Fracture mode analysis was performed using SEM. Bond strength mean values (MPa) were analyzed with ANOVA 3-way and Tukey's test (alpha = 5%). Dunnett's test was used to compare tested groups against Control groups of each adhesive system (alpha = 56%). SE primer presented lower mean bond strength values when compared to TE adhesives (p = 0.05). In addition, specimens restored with the SE primer did not resist to the 200,000 and 500,000 MC associated with TC. The application of 100,000 MC did not present a significant decrease in bond strength when compared to the control. Mixed failures were predominant for all groups. The higher the amount of thermal/mechanical cycles, the greater the number of mixed failures and the lower the percentage of adhesive failures.
TL;DR: Comparison of the adhesive groups at the enamel margin revealed that Adper Scotchbond Multi-Purpose exhibited significantly less leakage than the other adhesive groups (except iBond); among the self-etch adhesive groups, iB Bond exhibited significantly more leakage than Nano-Bond and 3) theother adhesive groups clustered intermediately.
Abstract: Clinical Relevance Decreased leakage was associated with Adper Scotchbond Multi-Purpose (total etch) and iBond (self-etch) systems in Class V resin composite restorations. All adhesive systems perf...
TL;DR: The chemical curing of the dual resin cement was not sufficient to compensate for the energy attenuation promoted by the interposition of A3.5 and A4 ceramic material with 4-mm of thickness, which had greater influence on the cement microhardness than the ceramic restoration shade.
Abstract: This study evaluated the microhardness of a dual resin cement under the influence of thickness and shade of a feldspathic ceramic. Ninety-five bovine incisors were selected; the crowns, with the roots removed, were embedded in a polystyrene resin and were randomly divided into 19 groups (n=5). On the buccal surface, a standardized cavity, 4.0 mm in diameter and 1.0 mm in depth, was prepared. Ceramic restorations (Noritake Ex 3) were manufactured with 4.0 mm diameter and 1, 2 and 4-mm thicknesses at shades A1, A2, A3, A3.5 and A4. A dual resin cement (Rely X-ARC) was inserted into the prepared cavity. A mylar strip was positioned over the prepared cavity, and light curing was performed for 40 seconds following the protocols: controls-without insertion of the restoration at distances of 0.0, 1.0, 2.0 and 4.0 mm. The remaining groups had the restorations positioned between the resin cement and light source during polymerization. The Vickers hardness test was performed on the cement layer with 50 g of load application for 30 seconds, with 5 indentations for each sample. Two-way ANOVA (5 x 3) and Tukey test (alpha = 0.05) were used to compare the results. The chemical curing of the dual resin cement was not sufficient to compensate for the energy attenuation promoted by the interposition of A3.5 and A4 ceramic material with 4-mm of thickness. The thickness had a greater influence on the cement microhardness than the ceramic restoration shade.
TL;DR: The demineralization effect of 2 different bleaching procedures on enamel surfaces with and without the post-treatment application of fluoride was determined and mineral loss and lesion depth were measured by microradiography.
Abstract: In this in vitro study, the demineralization effect of 2 different bleaching procedures on enamel surfaces with and without the post-treatment application of fluoride was determined. Bovine enamel specimens (n= 180) were ground flat, polished and divided into 6 groups. Group A (n=30) specimens were bleached with Opalescence, 10% carbamide peroxide (Ultradent Products, Inc) for 8 hours daily for 2 weeks; Group B (n=30) specimens were treated with Whitestrips, 5.3% hydrogen peroxide (Procter & Gamble) for 1 hour daily for 2 weeks; Group C (n=30): the same as Group A, but after bleaching, a fluoride varnish was applied on the specimens and left for 1 hour (Duraphat, 2.26% F-); Group D (n=30): the same as Group B, followed by the same fluoride application as Group C; Group E (n=30): the specimens were covered with a glycerin gel as a control group; Group F (n=30): specimens were kept in Coca Cola 1 hour daily for 2 weeks. The mineral loss (vol% microm) and lesion depth (microm) were measured by microradiography. Data analysis was accomplished using the Kolmogorov-Smirnov, Kruskal-Wallis and Mann-Whitney U tests (p<0.05) (SPSS 11.0). The median mineral loss was statistically significantly higher in the non-fluoride groups (A: 271.20 vs C: 128.00 and B: 364.90 vs D: 151.10). The highest mineral loss was found in Group F (581.85 vol% microm) and was lowest in Group E (32.80 vol% microm). No statistically significant difference between groups was found for lesion depth.
TL;DR: The interfacial dentin gap formation (IGW) of 2 etch & rinse and 3 self-etch systems with different degrees of acidity was measured and the correlation between the smear layer thickness and interfacial gap formation after 1 day and 6 months water storage was determined.
Abstract: PURPOSE: This study measured: 1) the interfacial dentin gap formation (IGW) of 2 etch & rinse and 3 self-etch systems with different degrees of acidity and determined the correlation between th ...