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Potassium nitrate (KNO 3) suppresses nociception induced by dental hypersensitivity (HYS). We aimed to examine the effects of KNO 3 on the neural activity of the trigeminal spinal subnucleus caudalis (Vc) in HYS model rats. KNO 3 or vehicle was applied to the exposed dentin of HYS rats for 3 days. c-Fos expression and neuronal activity in the Vc after acetone treatment for cold stimulation were examined to evaluate the effects of KNO 3 application on dentin. The number of c-Fos-immunoreactive cells in the Vc was lower in the group that received KNO 3 (KNO 3 group) than in the group that received vehicle (control group). Spike firing of Vc neurons in response to cold stimulation of the dentin was recorded before and after KNO 3 application to the cavity, and the increased neural activity was effectively suppressed by KNO 3 application. Scanning electron microscopy revealed that the dentin tubules were not occluded by deposits in any of the groups. KNO 3 -induced suppression of Vc neuronal activity does not involve physical occlusion of the dentin tubules but likely involves suppression of Aδ or C-fiber activities in the tooth pulp, resulting in the suppression of Vc neuronal activities. [ABSTRACT FROM AUTHOR]

Numerous laboratory evaluations have been conducted since Dr. Rafael Bowen introduced a method for determining the bond strengths of adhesive systems to dental substrates in 1965. Most of the past studies have been conducted using static bond strength tests, such as shear and tensile bond strength testing with either macro or micro sized specimens. These static bond strength tests are conducted using a monotonically increasing load in which stress is applied continuously until failure occurs. Although the type of stress that develops in static bond strength tests is not typically encountered in clinical situations, over the years clinicians have based their choice of adhesive systems for use in daily practice on the results of such tests. However, some well-known researchers have reported that the results obtained from static bond strength testing may have limited clinical relevance and should not be used only by themselves to make recommendations for clinical use. In clinical situations, restorations undergo cyclic stress during mastication at stress levels well below the breaking stress used in static bond strength tests. Thus, dynamic bond strength tests, using cyclic loading, should be more clinically relevant than static bond strength tests. Over 15 years, a testing method designed to assess fatigue bond strengths of dental adhesive systems has been developed through inter-collegial and international collaborative efforts. This review discusses the development of fatigue bond strength testing methodology, provides both a historical perspective and current information regarding available testing data for all categories of adhesive systems to enamel and dentin and perspectives on the future development of both adhesive systems and testing methods. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the protective effect of a glass ionomer cement (GIC) consisting of fluoro-zinc-silicate glass on the demineralization of bovine dentin using the ultrasonic pulse-echo method. The findings were compared with those obtained using a conventional GIC. Slabs of dentin from bovine teeth were sliced, shaped into a rectangular form, and immersed in 0.5 M ethylenediaminetetraacetic acid solution at 25ºC for 6 days, followed by storage in distilled water for 3 days. After demineralization, they were immersed in artificial saliva with and without the GIC specimens. The propagation times of the longitudinal ultrasonic waves in the samples were measured. The ultrasonic velocities of the fluoro-zinc-silicate glass-containing GICs were significantly increased 2-3 days after the start of the experiment and showed an upward trend thereafter. These findings indicate that the GICs containing fluoro-zinc-silicate glass might exhibit the potential to promote remineralization in the dentin. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated the influence of professional mechanical tooth cleaning (PMTC) pastes on the surface texture of different subject materials.Methods: Two one-step PMTC pastes, Clinpro Cleaning Paste for PMTC (CP) and PRG Pro-Care Gel (PG), and multiple-step PMTC pastes, Merssage Regular (MR), Merssagge Fine (MF), and Merssage Plus (MP), were used. For comparison, PMTC was performed using distilled water without paste (DW). The subjected materials used were bovine enamel (ENA) and dentin (DEN), a resin composite (FSU), and lithium disilicate (IEC). The prepared specimens were polished using a #2000-grit silicon carbide paper. PMTC was performed using a brush at 1,000 rpm for 15 s.Results: The surface roughness (Ra) values of the specimens before and after PMTC were measured by laser scanning microscopy. The Knoop hardness number (KHN) of the subjected material was obtained. The types of PMTC pastes and subject materials had a significant influence on the Ra values and KHN. For the majority of subject materials, the descending order of Ra values after PMTC was MR > MF > CP > PG > MP > DW. The descending order of KHN of the materials was IEC > ENA > FSU > DEN.Conclusion: Although one-step PMTC pastes appeared to be effective, it is important to consider the subject material during PMTC. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to evaluate the usefulness of coagulation biomarkers as predictors of the need for massive transfusion (MT) in patients with pelvic fractures.Methods: Patients who were treated for pelvic fractures in our hospital were divided into 2 groups: MT and non-MT. MT was defined as the transfusion of packed red blood cells (PRBCs) ≧10 units caused by bleeding within 24 h after admission. We compared variables between two groups, including vital signs, the scoring system and blood sample test. Additionally, we performed a multiple logistic regression analysis and a receiver operating characteristic curve analysis to reveal which value was the most useful predictive marker for MT in patients with pelvic fracture.Results: There were 22 patients in the MT group and 78 patients in the non-MT group. Patients in the MT group had significantly higher ISS than did those in the non-MT group. In contrast, the patients in the MT group had significantly lower RTS, TRISS Ps, sBP, Hb, lactate, BE, and Fbg levels. Lower sBP and Fbg levels were independent predictors for MT. The optimal cut-off values for sBP and Fbg levels were ≦109 mmHg and 193.0 mg/dL, respectively.Conclusions: The results of the study indicated that Fbg levels on admission can be an independent predictor of MT in patients with pelvic fractures. The optimal cut-off value of Fbg for MT prediction in this study was 193.0 mg/dL. [ABSTRACT FROM AUTHOR]

Introducing new technology in the dental school curriculum may face some uphill challenges navigating through university-level bureaucracy, financial ramifications, and influencing the mindset of certain faculty. A dental school that relies heavily on teaching traditional restorative procedures may particularly face many challenges to embrace new technology. The restorative department at a US dental school created a division of computer-aided design and computer-aided manufacturing (CAD/CAM) dentistry to introduce the concept of digital dentistry to dental students and faculty. This article describes methods that were adopted to improve acceptance and increase the productivity of chairside CAD/CAM restorations for both students and faculty at the dental school in US. [ABSTRACT FROM AUTHOR]

We investigated the influence of different curing modes on the mechanical properties and wear behavior of dual-cure provisional resin-based composites (DCPRs). Three DCPRs and a self-curing bis-acryl provisional resin-based composite were used. Flexural strength (σF), elastic modulus (E), resilience (R), and fracture toughness (KIC) were measured. The specimens were fabricated with and without light irradiation, stored in distilled water at 37°C for 24 h, and subjected to 5,000 or 10,000 thermal cycles. For sliding impact wear testing, 12 specimens were prepared with and without light irradiation. The maximum facet depth and volume loss were determined using a noncontact profilometer. Some of the mechanical properties and wear behavior of DCPRs are affected by light irradiation. This study indicated that proper light irradiation is important in polymerization process of the DCPRs to enhance the wear resistance and some mechanical properties. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the effect of desensitizing dentifrices containing stannous fluoride (SnF2) on dentinal tubule occlusion. Two experimental dentifrices with the same ingredients but different SnF2 concentrations (Group II, 0.4% w/w; Group III, 0.454% w/w) were used; distilled water was used in the control group (Group I). Third molars were collected from Japanese and American dental patients. The crowns were removed and sectioned to obtain dentin discs, which were further cut into quarters. Thirty-six specimens each from Japanese and American patients were divided into three sets (n = 12 each) and assigned to each of the three treatment groups. The specimens were brushed for 10 s twice per day for 4 days. After treatment, the discs were observed by scanning electron microscopy, and the extent of dentinal tubule occlusion in the images was expressed on a five-point categorical scale. Group II and III specimens from Japanese and American patients showed greater dentinal tube occlusion than those from Group I, but the differences were not statistically significant. The present results suggest that both SnF2 concentrations mitigate dentin hypersensitivity, regardless of patient ethnicity. [ABSTRACT FROM AUTHOR]

Abstract Objectives This study investigates the handling, mechanical, and wear properties of the newly developed flowable resin composites and elucidate the interrelations among the tested parameters. Methods Six flowable and two conventional resin composites are used. Five measurements are performed per resin composite to obtain the average inorganic filler content. Ten specimens per material are used to obtain the flexural strength, flexural modulus, and resilience. For sliding impact wear testing, twelve specimens are prepared. Noncontact profilometer and confocal laser scanning microscopy are used to determine the maximum facet depth and volume loss. Extrusion force and thread formation are used to measure the handling properties of the flowable resin composites. Six measurements are performed per flowable resin composite. Data evaluation is performed using analysis of variance and Tukey's honestly significant difference test at an α -level of 0.05. The correlation between the tested parameters is verified using the Pearson product-moment correlation coefficient. Results A subset of flowable resin composites exhibits higher flexural properties and wear resistance as compared to the conventional resin composites. The handling properties of the flowable resin composites are material dependent. Conclusion While the resilience parameters exhibit an extremely strong and statistically significant correlation with the wear parameters, the handling properties exhibit no interrelation with the remaining parameters. Significance While the handling properties of the newly developed flowable resin composites did not correlate with the mechanical and wear properties, some new flowable resin composites have the potential for use in high-stress bearing areas, such as posterior lesions, because of the enhanced mechanical properties and wear resistance. [ABSTRACT FROM AUTHOR]

The purpose of this case report is to describe a minimally invasive technique for non-vital tooth bleaching using traditional Japanese paper, known as washi. Non-vital tooth bleaching with a mixture of sodium perborate and 30% hydrogen peroxide rolled in Japanese paper for a traumatically injured tooth, and in-office vital-tooth bleaching for the upper front six teeth and first premolars, were performed. Five-year follow-up showed satisfactory stability in the bleaching effects and did not show any problems in the traumatically injured tooth. The use of Japanese paper for non-vital tooth bleaching may minimize damage to discolored non-vital teeth. [ABSTRACT FROM AUTHOR]

Abstract Objectives The purpose of this study was to investigate the simulated cuspal deflection and flexural properties of high viscosity bulk-fill and conventional resin composites. Methods Seven high viscosity bulk-fill resin composites and eight conventional resin composites were used. Aluminum blocks (10 mm x 8 mm x 15 mm) with a mesio-occlusal-distal (MOD) cavity [4 (W) mm x 8 (L) mm x 4 (D) mm] were prepared and randomly divided into groups for different measurement techniques [micrometer vs CSLM] and further subdivided according to type of resin composite (high viscosity bulk-fill vs conventional resin composite). The simulated cuspal deflection resulting from the polymerization of resin composite bonded to a precisely machined MOD cavity within an aluminum block was measured with either a novel highly accurate submicron digimatic micrometer (MDH-25 M, Mitsutoyo, Tokyo, Japan) or a confocal laser scanning microscope (CLSM, VK-9710, Keyence, Tokyo, Japan) cuspal measurement method. In addition, flexural properties of tested resin composites were measured to investigate the relationship between simulated cuspal deflection and flexural properties. Scanning electron microscopy observation of tested resin composites was also conducted. Results The simulated cuspal deflection of high viscosity bulk-fill resin composites was similar to that of conventional resin composites, regardless of measurement method. There were no statistically significant differences (p > 0.05) between the micrometer and CLSM cuspal measurement methods. There were statistically significant differences (p < 0.05) in flexural strength and elastic modulus depending on the material, regardless of the type of resin composite. Pearson correlation analysis did not show any statistically significant (p < 0.05) relationship between flexural properties and cuspal deflection. Conclusions The results of this study indicate that high viscosity bulk-fill resin composites show similar cuspal deflection with bulk-filling techniques, to those shown by conventional resin composites with incremental filling techniques. Simulated cuspal deflection can be measured using either a micrometer or CLSM, but this experiment failed to show any relationship between the flexural properties and simulated cuspal deflection of resin composites. Significance High viscosity bulk-fill resin composites produce the same level of cuspal deflection as a conventional incrementally filled resin composite. [ABSTRACT FROM AUTHOR]

This study evaluated the simulated localized wear of resin luting cements for universal adhesive systems using different curing modes. Five resin luting cements for universal adhesive systems were evaluated and subsequently subjected to wear challenge in a Leinfelder-Suzuki wear simulation device. Overall, 20 specimens from each resin luting cement were photo-cured for 40 s (dual-cure group), and 20 specimens of each material were not photo-cured (chemical-cure group). Simulated localized wear was generated using a stainless steel ball-bearing antagonist in water slurry of polymethylmethacrylate beads. In addition, scanning electron microscopy (SEM) observations of resin luting cements and wear facets were conducted. Significant differences in simulated wear and SEM observations of wear facets were evident among the materials in the dual- and chemical-cure groups. The simulated wear and SEM observations of wear facets of G-CEM LinkForce and Panavia V5 were not influenced by the curing mode. SEM observations of resin luting cements were material dependent. In most cases, dual curing appears to ensure greater wear resistance of resin luting cements than chemical curing alone. The wear resistance of some resin luting cements appears to be material dependent and is not influenced by the curing mode. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objectives The aim of this study was to determine the effect of double-layer application of universal adhesives on the bond quality and compare to other adhesive systems. Methods Two universal adhesives used were in this study: Scotchbond Universal (SU), [3M ESPE] and Prime & Bond elect (PE), [Dentsply Caulk]. The conventional single-step self-etch adhesives G-ӕnial Bond (GB), [GC Corporation.] and BeautiBond (BB), [Shofu Inc.], and a two-step self-etch adhesive, Optibond XTR (OX), [Kerr Corporation], were used as comparison adhesives. Shear bond strengths (SBS) and shear fatigue strengths (SFS) to human enamel and dentin were measured in single application mode and double application mode. For each test condition, 15 specimens were prepared for SBS testing and 30 specimens for SFS testing. Results Enamel and dentin SBS of the universal adhesives in the double application mode were significantly higher than those of the single application mode. In addition, the universal adhesives in the double application mode had significantly higher dentin SFS values than those of the single application mode. The two-step self-etch adhesive OX tended to have lower bond strengths in the double application mode, regardless of the test method or adherent substrate. Conclusion The double application mode is effective in enhancing SBS and SFS of universal adhesives, but not conventional two-step self-etch adhesives. Significance These results suggest that, although the double application mode may enhance the bonding quality of a universal adhesive, it may be counter-productive for two-step self-etch adhesives in clinical use. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the effect of frequency on shear fatigue strength (SFS). The SFS of a resin composite bonded to dentin was determined using three self-etch adhesive systems: G-ænial Bond, Scotchbond Universal, and Optibond XTR. The staircase method of fatigue testing was used to determine the SFS at frequencies of 5, 10, and 20 Hz for 50,000 cycles. The failed bonding sites observed were classified based on the type of bond failure as follows: adhesive failure, cohesive failure in composite, cohesive failure in dentin, or mixed failure (partially adhesive, partially cohesive). A modified t-test with Bonferroni correction was used to analyze the SFS data, and a complex chi-square test was used to analyze the fracture modes. The SFS of OX was significantly greater than that of GB at both 5 and 10 Hz. However, no significant differences in SFS were found among the three frequencies (5, 10, and 20 Hz) in the three self-etch adhesive systems. Furthermore, no significant differences in bond failure mode were observed among the three frequency rates in all the three adhesives used.(J Oral Sci 58, 539-546, 2016). [ABSTRACT FROM AUTHOR]

Objectives 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. Methods 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 5 Hz, 10 Hz, and 20 Hz. For each test condition, 30 specimens were prepared for the SFS testing. Results 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 20 Hz results tended to be higher. Conclusions Regardless of the self-etch adhesive system, frequencies of 5 Hz, 10 Hz, and 20 Hz produced similar results in fatigue strength of resin composite bonded to enamel using 50,000 cycles or until bond failure. Significance Accelerated fatigue testing provides valuable information regarding the long term durability of resin composite to enamel bonding using self-etch adhesive system. [ABSTRACT FROM AUTHOR]

Effects of a fluoride-releasing varnish containing surface reaction-type prereacted glass ionomer (S-PRG) filler on dentin demineralization were examined using optical coherence tomography. Bovine incisors that were sliced and treated with undersaturated 0.1 M lactic acid buffer solution (DE group). A thin film of varnish-containing S-PRG filler was applied before demineralization (PRG group). Control was maintained in artificial saliva. Using optical coherence tomography of selected locations on the dentin surface, peak intensity (dB) and width (pm) at 1/e2 were obtained and integrated values calculated. Although alterations in integrated values were different in each group, there was a slight but not significant increase in those for the control group and a slight but significant increase for the De group. For the PRG group, integrated values were doubled seven days after experiment initiation, followed by a significant increase. Fluoride-releasing varnish containing S-PRG fillers prevented dentin demineralization as detected by optical coherence tomography. [ABSTRACT FROM AUTHOR]

Improvements in dentin bonding systems have influenced modern restorative dentistry. The desire for minimal invasiveness has resulted in moreconservative cavity design, which basically relies on the effectiveness of current dentin bonding systems. Interaction of adhesives with enamel and dentin is based on two systems, commonly described as etchand- rinse and self-etch. Priming and bonding agents can be separate or combined, resulting in two- or three-step systems for etch-and-rinse adhesives and one- or two-step systems for self-etch adhesives. Selfetch systems use acidic functional monomers that simultaneously demineralize and impregnate tooth structures. Etch-and-rinse and self-etch systems have advantages and disadvantages, which are primarily related to the simplified bonding procedures required under clinical conditions. Knowledge of the composition, characteristics, and mechanisms of adhesion for each adhesive system is critical in selecting the ideal adhesive materials for clinical use. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine the effect of PRG filler extraction solution on the demineralization of enamel using optical coherence tomography (OCT). Bovine enamel was treated with lactic acid buffer solution and then placed in artificial saliva (De group). In the second group, specimens were stored in PRG filler extraction solution followed by immersion in lactic acid buffer solution (PRG group). In the control group, specimens were simply stored in artificial saliva. From the OCT image, the peak intensity (dB) and width at (1/e²) were obtained, and the integrated value was calculated. The data were analyzed using Tukey-Kramer tests (α=0.05). There was a slight but significant increase in the integrated value observed for the control group, and a slight but significant decrease in the value observed for the De group. For the PRG group, integrated values were doubled after seven days from the start of the experiment. [ABSTRACT FROM AUTHOR]

Ammonium hexafluorosilicate (AHF) has been applied to arrest caries without discoloration. The purpose of this study was to observe structural and elemental changes of demineralized and AHF applied primary tooth enamel. Enamel from the labial surface of 20 primary canines was divided into an unground side and ground side at the center of the tooth, and demineralized with 35% phosphoric acid for 6 min. The teeth were divided into 4 groups according to a 3-min application of AHF and 1 week of soaking in artificial saliva, as follows: group A (neither AHF nor saliva), group B (only saliva), group C (only AHF), and group D (AHF and saliva), and then subdi-vided according to whether the enamel was ground or unground. Specimens were analyzed with scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). The data were statisti-cally analyzed using ANOVA and Fisher's PLSD test at α = 0.05. In groups A and B, prism structures were seen, however, in groups C and D, enamel surfaces were covered with spherical particles. Ca/P ratio was significantly higher in groups C and D than in groups A and B. There was no significant difference between ground and unground enamel in the content of any element. The values for F, Na, Mg and Si persents and Ca/P ratio were significantly higher for the enamel surface than for points 10-30 ftm beneath the surface. Results of this study suggest the possibility that AHF treatment arrests caries, although further study will be required to confirm this result. [ABSTRACT FROM AUTHOR]

This study investigated the effect of a coating material containing S-PRG fillers on the demineralization of bovine enamel and dentin, by measuring changes in the transmitted ultrasonic velocity. Bovine enamel and dentin specimens with and without coating (ra=6 for each condition) were cut into blocks, immersed in 0.1 M lactic-acid buffer solution (pH 4.75) for 10 min twice daily throughout the test period, and stored in a demineralising artificial saliva solution (pH 7.0) between treatments. The propagation time of longitudinal ultrasonic waves was measured by a pulser-receiver with a transducer. Data were evaluated using ANOVA followed by Tukey's HSD test (a=0.05). The sonic velocity decreased over time for specimens stored in demineralising solution; however, coated specimens had a significantly higher sonic velocity than those without coating. The coating material containing pre-reacted glass-ionomer fillers therefore appeared to reduce the déminéralisation of enamel and dentin. [ABSTRACT FROM AUTHOR]

Silver diamine fluoride (Ag(NH3)2F) arrests caries but stains teeth black. To overcome this drawback, we applied ammonium hexafluoro-silicate (AHF; (NH4)2SiF6) and observed changes in the color and structure of demineralized enamel and dentin of extracted primary teeth. Enamel and dentin were demineralized in 10% EDTA solution for 90 s followed by 35% phosphoric acid gel for 60 s, then soaked in AHF solution for 60 s. Before analysis by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS), enamel and dentin were demineralized in 10% EDTA for 90 s. Teeth were divided into 4 groups according to AHF application and artificial saliva immersion status and then examined. The data were statistically analyzed using one-way ANOVA and Fisher's PLSD test at a significance level of P < 0.05. AHF treatment did not cause visible discoloration. Enamel prisms and dental tubules appeared by demineralization were covered with precipitates by AHF application. A sphere-filled membranous structure was observed in the saliva immersion groups. EDS analysis showed that AHF application had no effect on enamel; however, F% and Ca/P ratio were significantly higher on dentin surfaces after AHF application without artificial saliva immersion. Further study on arresting caries treatment is required. [ABSTRACT FROM AUTHOR]

The effect of warm air-drying on the dentin bond strengths of the single-step self-etch adhesives was determined. The adhesives were applied to bovine dentin followed by drying in a stream of warm air for 5, 10, and 15 s at 37°C. Resin composites were condensed into a mold and polymerized. Specimens were stored in distilled water at 37°C for 24 h, then shear tested. The surface free-energies were determined by measuring the contact angles of three test liquids placed on the cured adhesives. The dentin bond strengths varied according to the air-drying time. The value of the acid component increased slightly when drying was performed with a stream of warm air, whereas that of the base component decreased significantly. These data suggested that warm air-drying was essential to obtain adequate bond strengths, although increasing the drying time did not significantly influence the bond strength [ABSTRACT FROM AUTHOR]

Summary: This paper reviews the performance of current adhesive systems in tests of bond strength between resin composites and tooth structures. The longevity and success of resin composite restorations depend upon the adhesive systems providing durable bonds with tooth substances. Both in vitro and in vivo testing has been used to predict the clinical outcome of treatments with adhesive materials. Subtle variations in sample preparation can severely affect the bond strength, regardless of the test method employed. In addition to the large range of factors that affect bond strength, various load applications have been used to quantify the adhesion between composites and tooth structures. Dentin bond strength is normally evaluated by conducting mechanical tests in the tensile and/or shear mode, but the crosshead speeds used vary over a relatively wide range in the published literature. This review provides an overview of the current characterization of dental adhesives and the factors affecting their performance in bond-strength tests. [Copyright &y& Elsevier]

We compared the surface free energies and enamel bond strengths of single-step self-etch adhesives with and without an oxygen- inhibited layer. The adhesives were applied to the enamel surfaces of bovine incisors, light irradiated, and the oxygen-inhibited layer was either retained or removed with ethanol. The surface free energies and their components (γSLW, γS+, and γS-) were determined by measuring the contact angles of three test liquids placed on the cured adhesives. The enamel bond strengths of specimens with and without the oxygen-inhibited layer were measured. For all surfaces, the value of the estimated surface tension component γSLW was relatively constant. The value of the γS+ component increased slightly when the oxygen-inhibited layer was removed, whereas that of the γS- component decreased significantly. The enamel bond strengths of the self-etch adhesives were significantly lower in the specimens without an oxygen-inhibited layer. The oxygen-inhibited layer therefore appeared to promote higher enamel bond strength. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of polishing on surface roughness, gloss, and color of regular, opaque, and enamel shades for each of three resin composites. Two-mm-thick resin disks made with Estelite Σ Quick, Clearfil Majesty, and Beautifil II were final polished with 180-, 1000-, and 3000-grit silicon carbide paper. Surface roughness, gloss, and color were measured one week after curing. Estelite Σ Quick had significantly lower roughness values and significantly higher gloss values as compared with Clearfil Majesty and Beautifil II. The effects of surface roughness and gloss on color (L*a*b*) differed among resin composites and by shade. Correlation coefficients between surface roughness and L*a*b* color factors were generally high for Clearfil Majesty, partially high (i.e., between roughness and L*) for Beautifil II, and low for Estelite Σ Quick. Correlation coefficients between gloss and L*a*b* color parameters were generally high for Beautifil II and low for Estelite Σ Quick and Clearfil Majesty. However, for all resin composites, the values of the color differences between 3000-grit and 180-grit polishing groups for all shades were imperceptible by the naked eye. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of polishing on surface roughness, gloss, and color of regular, opaque, and enamel shades for each of three resin composites. Two-mm-thick resin disks made with Estelite Σ Quick, Clearfil Majesty, and Beautifil II were final polished with 180-, 1000-, and 3000-grit silicon carbide paper. Surface roughness, gloss, and color were measured one week after curing. Estelite Σ Quick had significantly lower roughness values and significantly higher gloss values as compared with Clearfil Majesty and Beautifil II. The effects of surface roughness and gloss on color (L*a*b*) differed among resin composites and by shade. Correlation coefficients between surface roughness and L*a*b* color factors were generally high for Clearfil Majesty, partially high (i.e., between roughness and L*) for Beautifil II, and low for Estelite Σ Quick. Correlation coefficients between gloss and L*a*b* color parameters were generally high for Beautifil II and low for Estelite Σ Quick and Clearfil Majesty. However, for all resin composites, the values of the color differences between 3000-grit and 180-grit polishing groups for all shades were imperceptible by the naked eye. (J Oral Sci 53, 283-291, 2011) [ABSTRACT FROM AUTHOR]

This study investigated the influence of the bonded surface area and the crosshead speed on the dentin bond strengths of self-etch adhesives. Bovine mandibular incisors were mounted in self-curing resin and the facial surfaces were wet ground with #600 silicon carbide (SiC) paper. The dentin surfaces were treated according to the manufacturer's instructions. Adhesives were applied, and the resin composites were condensed into molds (2.4 or 4.0 mm in internal diameter), placed on to the dentin, and then light activated. Ten samples per test group were shear tested at crosshead speeds of 0.1, 0.5, 1.0, 5.0, and 10.0 mm/mm. The results showed that higher crosshead speeds were associated with higher dentin bond strengths. This relationship was more significant for specimens with a smaller dentin bonding surface area. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of the specular component mode of specular component included (SCI) and specular component excluded (SCE), and the grit size of final polishing with SiC paper on color of different types of resin composites and shades. Resin disks of 2 mm in thickness were made with regular, opaque and enamel shades for each of the following: supra-nano spherical filled Estelite Σ Quick (EQ), organic filled hybrid Clearfil Majesty (CM), and S-PRG filled nano-hybrid Beautifil II (B2). One week after curing, the surface roughness and color were measured. Color differences between 3000- and 1000-grit, and between 3000- and 180-grit final polishing groups were calculated. Comparison of L*a*b* between SCI and SCE modes showed that the L* values with SCI were significantly higher than those with SCE in 1000- and 3000-grit groups for EQ and CM, and in 3000-grit group for B2. Comparison of total color differences (ΔE*ab) between SCI and SCE modes for all resin composites and shades in all polishing groups showed that the ΔE*ab with SCE were higher than those with SCI except for opaque shade of EQ with white background in 1000-grit group in which the ΔE*ab values were same. The effect of the specular component mode and polishing on color differed among the resin composites and shades. [ABSTRACT FROM AUTHOR]

This study examined the relationship between the adhesive application time and enamel bond strength of several single-step self-etch adhesive systems. The adhesives used were: Bond Force (BF, Tokuyama Dental Corporation, Tokyo, Japan), Clearfil tri-S Bond (CT, Kuraray Medical Inc, Tokyo, Japan), iBond Self-Etch (IB, Heraeus Kulzer, Armonk, NY) and OptiBond All-in-One (OB, sds Kerr). Bovine mandibular incisors were mounted in self-curing resin and wet ground with #600-grit silicon carbide paper to expose labial enamel. Adhesives were applied for 10, 20 or 40 seconds and the resin composites were condensed into a mold (∅4 x 2 mm) on the enamel and light irradiated. Ten samples per test group were stored in 37°C water for 24 hours, then shear tested at a crosshead speed of 1.0 mm/minute. One-way ANOVA and the Tukey HSD test (α=0.05) were performed within each adhesive system. The enamel surfaces after adhesive application were also observed in a Field Emission Electron Probe Surface Roughness Analyzer and the Ra value was calculated. The enamel bond strength ranged from 13.6 to 17.8 MPa for BF, 13.6 to 15.9 MPa for CT, 14.3 to 16.2 MPa for IB and 13.4 to 19.8 MPa for OB. Significant increases in bond strength were found for the 40-second application groups, except for IB. No changes in Ra value were found for BF and IB, while significant decreases in Ra value were recorded with 40-second application for CT and OB. The data suggested that the duration of the single-step self-etch adhesive application was a crucial factor for determining the enamel bond strengths of some of the single-step self-etch adhesives employed in the current study. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effect of previous phosphoric acid etching on the dentin bond strength of single-step self-etch adhesive systems. Facial surfaces of bovine teeth were wet ground with #600 SiC paper. Adhesives were applied with and without previous phosphoric acid etching, and light irradiated. Resin composite was bonded to the adherend surface, followed by light irradiation and storage in water at 37°C. Four groups (n = 10) were made per adhesive system: with and without previous acid etching and with and without thermal cycling between 5°C and 55°C for 10,000 cycles. Specimens were tested in a shear mode at a crosshead speed of 1.0 mm/min. Two-way ANOVA and Tukey HSD test at a level of 0.05 were performed. The changes in dentin bond strengths were different among the adhesive systems tested. In all experimental conditions of this study, the dentin bond strength decreased or remained unchanged with previous acid etching. From the results of this study, previous acid etching might not be acceptable for increasing dentin bond strength of the single-step self-etch adhesive systems. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the development of shear bond strength of resin composites using self-etching primer systems. Four different types of self-etching primer systems with different combinations of their recommended resin composites were used. Bovine incisors were mounted in self-curing resin and the facial surfaces were wet ground on #600-SiC paper to expose the dentin. The shear bond strengths of ten samples per test group were measured at a crosshead speed of 1.0 mm/min after storage for 5, 10, and 60 min, and 24 h in distilled water at 37°C. One-way ANOVA followed by Dunnett's test (α = 0.05) was used to examine the significance of differences between the mean bond strength at 24 h and each of the other storage periods. The dentin bond strengths of all the materials tested increased with prolonged storage time. Such differences in the changes in bond strength might have clinical implications if a restoration is subjected to high stress immediately after it has been placed. It is important to consider the development of dentin bond strength to allow the materials sufficient maturation time prior to functional loading or application of other forms of external stress. [ABSTRACT FROM AUTHOR]

Color characteristics of the shades for different filler type resin composites were compared in the reflectance and transmittance modes, and specular component included (SCI) and specular component excluded (SCE) geometries for reflectance mode. Resin composites and shades used in this study were submicron filled Estelite Σ (Σ: Inc, A2, A3, B3, C2, OA2, OA3) and nanofilled Filtek™ Supreme XT (XT: Clear, A2E, A2B, A3B, C2B, A2D, A3D). Resin disks of 2 mm in thickness and final polish with 2,400-grit silicon carbide paper were kept in 100% humidity. One week after curing, color of the resin disks were measured with a spectrophotometer. Both for Σ and XT, reflectance of each of all shades measured with SCI were significantly higher than those with SCE. Compared to the values with SCI and SCE, the L* with SCI were significantly higher for all shades of Σ and XT, however, a* and b* were depended with brands and shades. Different filler type resin composites showed different color characteristics, reflectance, transmittance and L*a*b* distribution. In some shades, color difference between the measurement with SCI and SCE was visually perceptible level. It would be concluded that the color of resin composite measured with the SCI and SCE geometries differed. [ABSTRACT FROM AUTHOR]