Resin Tag Length Research Articles

In vitro Investigation of Resin Tag Lengths of Three Commercially Available Pit and Fissure Sealants.

The aim of this in vitro study was to perform a comparative evaluation of the length of resin tags produced by three different types of pit and fissure sealants (Embrace WetBond, Helioseal Clear, and Fuji VII) using scanning electron microscopy. Thirty extracted mandibular premolars were randomly divided into three groups of ten. Each group was treated with one of the sealants - Embrace WetBond, Helioseal Clear, or Fuji VII. Following cleaning and preparation, the sealants were applied according to the manufacturer's instructions. Teeth were then sectioned and prepared for SEM investigation, and the length of resin tags was measured. Scanning electron microscopy revealed Embrace WetBond produced significantly longer resin tags than Helioseal Clear and Fuji VII. The study concludes that Embrace WetBond sealant exhibited the longest resin tags, which may suggest a stronger mechanical bond to enamel.

Evaluation of the Dentinal Shear Bond Strength and Resin Interface in Primary Molars after Pre-Treatment with Various Dentin Bio-Modifiers: An In Vitro Study.

Dentine adhesives have demonstrated great success with permanent teeth. Though the results in primary teeth are not well documented, some studies have demonstrated lower values of bond strength in primary teeth than those found in permanent teeth. The aim of this study was to compare and evaluate the effect of grape seed extract (6.5%) (Herbal Bio Solutions, Delhi, India), glutaraldehyde (5%) (Loba Chemie PVT. LTD., Mumbai), hesperidin (0.5%) (Herbal Bio Solutions, Delhi, India), and casein phosphopeptide-amorphous calcium phosphate (tooth mousse) (GC Corporation, Alsip, IL, USA) on the shear bond strength of dentine of primary teeth and to evaluate the resin tags at the resin tooth interface. Seventy-five caries-free human primary molars were collected, and their occlusal surfaces were ground flat. Dentin surfaces were etched using phosphoric acid. Then teeth were randomly assigned in sequential order to five groups according to the dentinal treatment method: Group I (Control group) (no treatment), Group II (5% glutaraldehyde), Group III (6.5% grape seed extract), Group IV (0.5% hesperidin), and Group V (CPP-ACP). Ten teeth from each group were assigned for Shear Bond Strength and five for SEM analysis. ANOVA and a post hoc least significant difference test (p < 0.05) were used for statistical analysis of the collected data. The grape seed extract group showed significantly increased shear bond strength than the control group (p < 0.05), and the mean length of resin tags in different dentine bio modifiers groups was also statistically significant (p < 0.05). The use of dentin bio modifiers such as 5% glutaraldehyde, 6.5% grape seed extract, 0.5% hesperidin, and CPP-ACP in the bonding process for primary teeth did not improve the dentinal bond strength.

Polyvinylpyrrolidone as a primer for resin-dentin bonding

ObjectiveThis study aimed to investigate the effects of polyvinylpyrrolidone (PVP)-containing primer (PCP) on dentin bonding. MethodsPVP and anhydrous ethanol were used to prepare the PCPs, which were prepared at concentrations of 0.5%, 1%, and 2% (w/v). These PCPs were subsequently applied to the dentin surface, denoted as E1, E2, and E3, respectively. In the control group, no primer was applied. Following the treatment, the dentin surfaces were subjected to analysis using Fourier-transform infrared spectroscopy (FTIR), and the micro-tensile bond strength (MTBS) was evaluated. The failure mode, nanoleakage, and bonding longitudinal section were observed utilizing scanning electron microscopy (SEM). Additionally, the effect of PCPs on matrix metalloproteinases (MMPs) activity was analyzed through an in situ zymography test. Data were subjected to statistical analysis using ANOVA tests (α = 0.05). ResultsSignificant alterations in the infrared resonances associated with collagen cross-linking within the collagen matrix were observed across all PCP groups. The application of PCP demonstrated a noteworthy enhancement in micro-tensile bond strength (MTBS) compared to group C (p < 0.05). Notably, group C exhibited the lowest MTBS (41 ± 7.7 MPa), whereas group E2 demonstrated the highest MTBS (66 ± 11.9 MPa). Even after undergoing aging, the MTBS of the PCP groups remained superior to that of group C (p < 0.05). The resin tag length in the PCP groups was found to be greater than that of group C, and the occurrence of nanoleakage was comparatively lower in the PCP groups, both before and after aging. Additionally, PCP exhibited a dose-dependent inhibition of matrix metalloproteinases (MMPs) activity, which was statistically significant (p < 0.05). ConclusionsThe utilization of PCP Primer exhibits notable enhancements in bond strength, mitigates nano-leakage, and suppresses enzyme activity within the hybrid layer.

In Vitro Evaluation of Viscosity, Depth of Penetration, Microleakage, and Shear Bond Strength of Conventional and Hydrophilic Sealants.

Sealants are effective in preventing and arresting pit and fissure caries. Newer brands of sealants continue to be developed despite the lack of scientifically based information addressing the caries-preventive properties of these materials. Hence, laboratory in vitro tests play a vital role in providing the necessary information regarding the efficacy of new products in a short period of time. To compare and evaluate the viscosity, resin tag length, microleakage, and shear bond strength between conventional and hydrophilic sealants. A total of 40 extracted third molars were selected. Only 20 were evaluated for microleakage and resin tag length and another 20 for shear bond strength evaluation between group I-ClinPro and group II-UltraSeal XT hydro. After sealant placement, specimens were immersed in 0.1% rhodamine dye, followed by thermocycling. Microleakage testing was done using a confocal laser scanning microscope and resin tag length evaluation using a scanning electron microscope (SEM) and shear bond strength using an Universal Instron machine. Viscosity was assessed using an Anton Paar viscometer. Results were subjected to statistical analysis using Statistical Package for the Social Sciences (SPSS) software version 20. Viscosity and mean microleakage scores for group I (0.92 MPa and 1.50) were found to be higher than for group II (0.72 MPa and 0.60). Mean resin tag length and mean shear bond strength for group I (7.46 ± 0.95 μm and 13.71 ± 0.94 MPa) were found to be less compared to group II (10.03 ± 1.00 μm and 20.39 ± 0.98 MPa). The results were found to be statistically significant (p < 0.05). Group II was found to be less viscous, which resulted in the formation of resin tags of sufficient length and showed less microleakage and higher shear bond strength than group I. Prabakar J, Jeevanandan G, Kengadaran S. In Vitro Evaluation of Viscosity, Depth of Penetration, Microleakage, and Shear Bond Strength of Conventional and Hydrophilic Sealants. Int J Clin Pediatr Dent 2023;16(5):745-750.

In Vitro Analysis of Hydrophilic and Conventional sealants - A comparative study

Background: According to the World Health Organization, filling up the pits and fissures is one of the most efficient, least invasive ways to completely protect the occlusal surface from the carious phenomena. In vitro tests are essential for quickly delivering the knowledge required about the effectiveness of more recent sealant brands. Consequently, the objective of the current study was to assess and contrast the viscosity and length of resin tags on permanent molars of conventional and hydrophilic sealants. Materials and Methods: Twenty extracted third molars were split into two groups at random, one receiving conventional sealant (Clinpro 3M ESPE), and the other receiving hydrophilic sealant (UltraSeal XT Hydro). Each tooth's occlusal surfaces underwent an acid etchant pretreatment before the appropriate sealants were applied. Afterwards thermocycling and longitudinal sectioning were applied to both groups. For the purpose of measuring the length of the resin tag, the sectioned tooth specimens were examined under a scanning electron microscope. An Anton Paar viscometer was used to measure viscosities. The difference between the mean resin tag length of Group I and Group II sealants was compared using an independent t-test. Results: The mean resin tag length of Group II (10.07+/- 1.01m) was found to be higher than Group I (7.49+/- 0.94m), and this difference was statistically significant (P = 0.001). The viscosity measurements of Groups I and II were determined to be 0.8 mega Pascal (MPa) and 0.6 MPa, respectively. Conclusion: Based on the findings of the current investigation, it can be said that Group II sealants generated resin tags of sufficient length and had lower viscosities than Group I sealants. Thus, a hydrophilic sealant outperformed a conventional sealant in terms of performance.

Effects of carbodiimide combined with ethanol-wet bonding pretreatment on dentin bonding properties: an in vitro study.

PurposeThis study evaluated the combined effects of Carbodiimide (EDC) and ethanol–wet bonding (EWB) pretreatment on the bond strength and resin–dentin surface.MethodsPhosphoric acid-etched dentin specimens were randomly divided into five groups based on the following pretreatments: deionized water (control), EWB, 0.3M EDC in water (EDCw), EDC water solution combined EWB (EDCw + EWB), and 0.3M EDC in ethanol (EDCe). A scanning electron microscope (SEM) was used to observe the morphology of collagen fibrils on the demineralized dentin matrix in each group after pretreatment. The adhesives Prime & Bond NT (PB) (Dentsply De trey, Konstanz, Germany) or Single bond 2 (SB) (3M ESPE, St. Paul, MN, USA) was applied after pretreatments, and a confocal laser scanning microscope (CLSM) was used to evaluate the quality of resin tags. The degree of conversion (DC) of the adhesive was investigated by Fourier transform infrared spectroscopy (ATR-FTIR). The dentin was first bonded with resin and bathed in water at 37 °C for 24 h. Half of them were subjected to 10, 000 cycles in a thermocycler between 5 °C and 55 °C before a microshear bond strength (µSBS) test. The statistical methods were Analysis of Variance (ANOVA) and a Tukey post hoc test at α = 0.05.ResultsThe µSBS was significantly affected by pretreatments (p < 0.001), adhesives (p < 0.001), and aging conditions (p < 0.001) as revealed by the three-way ANOVA. The EDCw, EDCw + EWB, and EDCe groups significantly increased the µSBS; the EDCw + EWB and EDCe groups produced the highest µSBS. In the EDC-containing groups, the SEM showed at the collagen fibrils in the dentin matrix formed a three-dimensional network structure in the tubules after cross-linking into sheets, and the hybrid layer formed thicker resin tags under a CLSM. In the EDC-containing groups, the CLSM observed an increase in the length of resin tags. PB showed a higher DC and bonding strength than SB, and the five pretreatment groups tested did not affect the DC of the two adhesives.ConclusionsIn etch–and–rinse bonding system, EDC combined with EWB pretreatment can improve the quality of the hybrid layer and enhance the mechanical properties of demineralized dentin matrix. Pretreatment with EDC–ethanol solution may be a new clinically friendly option for enhancing dentin bonding durability.

Evaluation of six different one-step universal adhesive systems in terms of dentin bond strength, adhesive interface characterization, surface tension, contact angle, degree of conversion and solvent evaporation after immediate and delayed use.

In this study, it was aimed to investigate the effects of different waiting periods on resin-dentin bond strength (BS), degree of conversion (DC), contact angle (CA), surface tension (ST), solvent evaporation (weight loss) and the characteristics of adhesive interfaces of the current six universal adhesive resins (ARs). A total of 216 caries-free human lower third molar teeth were used. Composite resin restorations were performed by applying six universal ARs in etch-and-rinse and self-etch mode on standardized dentin surfaces after 0, 5, and 30 min waiting time. Then, a micro-shear BS test, SEM examination and characterization of the adhesive interface were performed. In addition, DC, CA, ST, solvent evaporation of all tested ARs were evaluated. The obtained data were statistically anaIyzed. The tested ARs did not show any statistical difference between 0 and 5min evaluations in all parameters evaluated except for weight loss (p > 0.05). While the weight loss, ST and CA of all ARs increased in 30 min (p < 0.05), the BS, DC, thickness of the adhesive layer and the hybrid layer, resin tag length and number of resin tags varied according to the ARs used. When the ARs were used in etch-and-rinse mode, all the parameters evaluated also varied according to the AR used. Higher adhesive layer thickness and lower hybrid layer thickness were found in the self-etch mode (p < 0.05). All of the adhesives tested can be safely used up to 30 min. This could also prevent economical loss caused by waste adhesive material. It is important to know how the bond strength, degree of conversion, adhesion, contact angle and surface tension properties of the adhesive resin waiting in the dispensing cup for a long time during clinical use are affected to make ideal restorations.

An In Vitro Study of Three Types of Pit and Fissure Sealants for Viscosity, Resin Tag, and Microleakage: A Scanning Electron Microscope Study.

IntroductionOne of the important techniques for prevention of dental caries is the application of pit and fissure sealants. The sealant success depends on not only adhering firmly to the enamel surface, but also isolation of pits and fissures from the rest of the oral environment.The study was conducted to evaluate and compare three pit and fissure sealant materials for viscosity, microleakage, and resin tag length.Materials and methodsSixty premolars were selected for the study. The teeth were randomly divided into three groups. Group I: type VII GIC, group II: Delton FS, group III: Delton. Teeth were prepared by pumice prophylaxis and etched with 37% phosphoric acid. The respective pit and fissure sealants were applied. Teeth were stored in 1% methylene blue dye and sectioned mesiodistally into two halves. The microleakage was assessed using stereomicroscope and resin tag length using scanning electron microscope (SEM). Brookfield's viscometer was used to measure the viscosity.ResultViscosity was lowest for Delton and highest for type VII GIC. Microleakage was seen least with the Delton (0.0%) sealant, followed by Delton FS (20.0%), and highest in Type VII GIC (85.0%) in the scoring criteria of 3 and 4 and the mean length of the resin tags was least for Type VII GIC was 3.79 ± 2.58 µm, followed by Delton FS was 5.60 ± 2.12 µm, and highest for Delton was 7.27 ± 3.43 µm. The relation between viscosity, resin tag length, and microleakage was negative. As the viscosity gets lower, the more long the resin tags formed and the microleakage decreased. Delton pit and fissure sealant had lowest viscosity and microleakage scores while longest resin tag lengths.ConclusionDelton with the lowest viscosity and microleakage appears to be a more suitable pit and fissure sealant compatible with residual moisture and ideal for use in children, where isolation is a problem.How to cite this articleSingh R, Lakhanam M. An In Vitro Study of Three Types of Pit and Fissure Sealants for Viscosity, Resin Tag, and Microleakage: A Scanning Electron Microscope Study. Int J Clin Pediatr Dent 2022;15(3):304-310.

Comparative Evaluation of Resin Dentin Interface using Universal and Total- Etch Adhesive Systems on Sound and Eroded Dentin: In Vitro Study.

Objective This study aimed to compare the resin-dentin interface of sound and eroded dentin using universal and total-etch adhesive systems. Materials and Methods Forty caries-free extracted human premolars were collected, and the occlusal surfaces were ground by using slow speed diamond disc with copious water supply until a flat superficial dentin was exposed. The test group underwent erosive cycle (n = 20), and another group (n = 20) was reserved for control group. Erosive protocol consisted of immersion in 1.23% citric acid for 1 minute every 12 hours and stored in artificial saliva. Both the control and eroded teeth were further subdivided (n = 10) for composite restoration by using either self-etch or total-etch systems. Then the tooth samples were sectioned longitudinally and observed under confocal laser scanning microscope at ×10 magnification to evaluate resin tag length and hybrid layer thickness. Statistical Analysis The data obtained were analyzed by using independent t-test. Results The highest mean value of the resin tag length and thickness of hybrid layer was observed with total-etch system in sound dentin group compared with other groups (p < 0.001). Conclusion The resin-dentin interface of sound dentin was found to be better than eroded dentin by using total-etch system. The resin-dentin interface of eroded dentin was superior to sound dentin by using self-etch adhesive system.

Does Adhesive Layer Thickness and Tag Length Influence Short/Long-Term Bond Strength of Universal Adhesive Systems? An In-Vitro Study

(1) Background: This study investigated the effect of the adhesive layer thickness and the length of resin tags on dentin bond strength of five universal adhesives applied in self-etch mode. (2) Methods: One hundred and fifty extracted human third molars were used. Five different universal adhesives were applied in self-etch mode on the dentin surface. Half of the specimens were subjected to an aging procedure for six months. A shear bond strength (SBS) test was performed and the results were statistically analyzed with a t-test and one-way ANOVA test. Scanning electron microscopy (SEM) was executed to measure the adhesive layer thickness and tag depth. (3) Results: No statistical differences were found between the five adhesive systems after a 24 h storage period, regardless of layer thickness and tag depth (p &lt; 0.05). After 6 months of aging in water at 37 °C, Iperbond Max and Scotchbond Universal preserved the bond strength over time (p &lt; 0.05), whilst the SBS of Iperbond Ultra, FuturaBond M+, and Ibond Universal decreased significantly after the aging period. No relation was observed between the adhesive thickness or tags’ length on SBS. (4) Conclusions: Within the limitation of this study, the stability over time of the bond strength of universal adhesives depends on their compositions regardless of the adhesive layer thickness and/or tags’ length.

Microleakage and characteristics of resin-tooth tissues interface of a self-etch and an etch-and-rinse adhesive systems.

ObjectivesThis study was conducted to compare the microleakage and characteristics of the resin-tooth tissue interface between self-etch and etch-and-rinse adhesive systems after 48 hours and 3 months.Materials and Methods40 extracted premolar teeth were randomly divided into 2 groups: 1-step self-etch adhesive system – Optibond™ All-In-One, and 2-step etch-and-rinse adhesive system - Adper™ Single Bond 2. Both groups were subjected to 500 thermocycles (5°C–55°C) before scanning electron microscope (SEM) analysis or microleakage trial at 48-hour and 3-month time periods.ResultsSEM images showed the hybrid layer thickness, diameter, and length of resin tags of the self-etch adhesive (0.42 ± 0.14 µm; 1.49 ± 0.45 µm; 16.35 ± 14.26 µm) were smaller than those of the etch-and-rinse adhesive (4.39 ± 1.52 µm; 3.49 ± 1 µm; 52.81 ± 35.81 µm). In dentin, the microleakage scores of the 2 adhesives were not different in both time periods (48 hours/3 months). However, the microleakage score of etch-and-rinse adhesive increased significantly after 3 months (0.8 ± 0.63 and 1.9 ± 0.88, p < 0.05).ConclusionsThe self-etch adhesive exhibited better long-term sealing ability in dentin when compared to that of the etch-and-rinse adhesive. The greater hybrid layer thickness and dimensions of resin tags did not guarantee reliable, long-lasting sealing in the bonding area.

Effects of simplified ethanol–wet bonding and hydrophobic coating on resin–dentin bonding properties

The purpose of the present study is to evaluate the impact of simplified ethanol-wet bonding (EWB) and hydrophobic coating (HC) on the three adhesives. We collected 105 fresh human molars and randomly divided them into three groups according to the three types of adhesives: Single Bond (SB), Gluma Comfort Bond (GB), and Tetric N-Bond (TB). Then, each group was further divided into five subgroups based on different bonding schemes: (1) Water wetting bonding (WWB); (2) EWB for 1 min (EWB 1); (3) EWB for 2 min (EWB 2); (4) EWB for 1 min combined with HC (EWB 1 + HC); and (5) HC. We evaluated the micro-tensile bonding strength (MTBS), fracture types, hybrid layer and resin tags of the specimens. At 24 h, SB (EWB 2), GB (EWB 2), TB (EWB 2), GB (HC), TB (HC), TB (EWB 1) and TB (EWB 1 + HC) groups revealed significant improvement in MTBS (p＜0.05); After 6 months, SB (EWB 1 + HC), GB (EWB 2), and TB (HC) groups showed no significant reduction in MTBS (p＜0.05). Besides, EWB 2 has the most noticeable effect on both hybrid layer and resin tags in all adhesives; EWB 1 + HC or HC alone scheme increase the number and length of resin tags in partly adhesives. Simplified ethanol wetting technology can increase the bond strength, durability, and quality of the three adhesives, and its effect depends on the wetting time. In this study, ethanol wetting for 2 min improved the adhesion properties significantly.

BOND STRENGTH AND MICROMORPHOLOGICAL FEATURES OF DENTIN SUBSTRATES TREATED WITH DIFFERENT ETCHING MODES USING UNIVERSAL ADHESIVE SYSTEM

This in-vitro study assessed bond strength and micromorphological features of dentin substrates treated with different etching modes using universal adhesive system. A total of 28 freshly extracted human molars with coronal dentin caries were used for this study. A total of 80 composite microcylinders with prepared dentin surface containing both sound dentin and carious affected dentin were divided into two main groups (40 each) according to the bonding mode used: Self-etch mode in one step single dose, and total-etch mode in two steps. Each group was then subdivided into two subgroups (20 specimens each) according to the type of dentin substrate used: Sound dentin and caries affected dentin. For the Scanning Electron Microscope (SEM) examinations, the teeth were divided into two main groups (8 each) according to the bonding mode used: Self-etch mode in one step single dose, and total-etch mode in two steps. Each group was then subdivided into two subgroups (4 specimens each) according to the type of dentin substrate used: sound dentin and caries affected dentin. The interfacial zone was examined using SEM at magnification 5000 X. Data was then recorded, tabulated and statistically analyzed. For sound dentin using total-etch mode (24.02 ± 1.03 MPa) showed statistically significantly lower µSBS than that using self-etch mode (28.04 ± 1.30 MPa) at p<0.05. For caries affected dentin using total-etch mode (18.46 ± 0.86 MPa) showed statistically significantly higher mean µSBS than that using self-etch mode (16.48 ± 0.84 MPa) at p<0.05. Independent of the etch mode used for bonding, sound dentin showed statistically significantly higher mean µSBS than that of caries affected dentin at p<0.05. These results were confirmed by the examination of the SEM images which revealed increase in number and length of resin tags for the groups showing high µSBS. In conclusion, using self-etch universal adhesives on sound dentin is considered to be material dependent. And using total-etch mode of universal adhesive on caries affected dentin can enhance bond strength. Moreover, the type of substrate and etching strategies may affect the bonding performance and durability of restorations in dentistry.

The effect of vitality and dentin depth on resin tags length of resin-dentin interface in dogs' teeth.

The aim of this study was to evaluate the effect of pulpal pressure and dentin depth on the quality of hybrid layer of bonded composite. Four healthy dogs, aged between 12 and 18 months, with intact dentitions were used for the experimental work. A total of 24 teeth were available for the study by using the six upper anterior teeth of each of the four dogs used in the study. The 24 teeth included in the study were divided according to presence or absence of pulpal pressure (P) into two groups with 12 teeth in each group. P1 teeth with positive pulpal pressure and P2 teeth with no pulpal pressure. Each of these two groups was further divided into two subgroups, according to the cavity depth (D) they received, where in D1 a class V cavity with depth of 1 mm was performed, while in D2 a class V cavity with depth of 2 mm was performed. The cavities were restored with micro hybrid composite restorative material and the samples were then left in the dogs’ mouth for 30 days. At the end of the experimental period, the dogs were euthanized by injecting an overdose of thiopental sodium. The anterior part of the upper jaw was sawed out of each dog’s mouth and the teeth were sectioned to evaluate the resin–dentin interface using Environmental Scanning Electronic Microscope. Results of the study showed that the mean resin tag length value was significantly affected by vitality and dentin depth. The presence of pulpal pressure together with depth of dentin could adversely affect the quality of hybridization.

Comparative Evaluation of the Viscosity and Length of Resin Tags of Conventional and Hydrophilic Pit and Fissure Sealants on Permanent Molars: An In vitro Study.

Background:The World Health Organization considers sealing the pit and fissures as a primary preventive measure and is one of the most effective, least invasive means to ensure the complete protection of the occlusal surface from the carious phenomenon. In vitro tests play a vital role in providing the necessary information regarding the efficacy of newer brands of sealants in a short period. Therefore, the aim of the present study was to evaluate and compare the viscosity and length of resin tag of conventional and hydrophilic sealant on permanent molars.Materials and Methods:Twenty extracted third molars were randomly divided into two groups: Group I: Conventional sealant (Clinpro 3M ESPE) and Group II: Hydrophilic sealant (UltraSeal XT Hydro). Occlusal surfaces of each tooth were pretreated with the acid etchant, and the respective sealants were placed. Both the groups were then subjected to thermocycling and sectioned longitudinally. The sectioned tooth specimens were examined under scanning electron microscope for resin tag length measurements. Viscosities were evaluated using an Anton Paar viscometer. Independent t-test was used to compare the difference in mean resin tag length of Group I and Group II sealants.Results:Viscosity measurements of Group I and Group II were found to be 0.9 mega Pascal (MPa) and 0.7 MPa and the mean resin tag length of Group II (10.03 ± 1.00 μm) was found to be higher than Group I (7.46 ± 0.95 μm) and was found to be significant statistically (P = 0.001).Conclusion:Based on the results of the present study, it can be concluded that Group II sealant exhibited lower viscosity and formed resin tag of sufficient length than that of Group I sealants. Therefore, hydrophilic sealant showed better results as compared to a conventional sealant.

BOND STRENGTH AND INTERFACIAL MORPHOLOGY OF A MULTIMODE ADHESIVE RESIN CEMENT TO ENAMEL AND DENTIN

Introduction: Resin cements are used for cementation of indirect restorations. A high-quality adhesion to tooth structure is primordial for the success of indirect cemented restorations. Objectives: Were to assess the shear bond strength of RelyX ultimate adhesive resin cement to both enamel and dentin when used in different application modes (self-etch and total-etch) and to study resin-tooth interfaces using SEM. Materials and methods: 40 enamel specimens and 40 dentin specimens were used in this study. Each substrate specimens were randomly divided into four groups of 10 specimens each according to resin cement applied: Enamel groups: Group A1: RelyX ultimate as total-etch; Group A2: RelyX ultimate as self-etch; Group A3: Variolink II; Group A4: Multilink automix. Dentin groups: Group B1: RelyX ultimate as total-etch; Group B2: RelyX ultimate as self-etch; Group B3: Variolink II; Group B4: Multilink automix. Resin cements were built over the surfaces following manufacturer's instructions in a plastic tube. All specimens were thermocycled (500 cycles, 5°/55°C, 15 sec dwell time) then shear bond strength was measured in MPa and data were analyzed using F-test (ANOVA) and Post Hoc test. Three specimens from each group were further sectioned, gold sputtered and evaluated under SEM. Results: All enamel groups showed a statistically significant difference for shear bond strength with P <0.001. Group A1 revealed the highest mean value of 35.60 MPa. While for dentin, there was no statistically significant differences among groups with P=0.053. Interfacial morphology of RelyX ultimate in total-etch mode showed better interface morphology and improved tag length compared to respective self-etch counterpart. Conclusions: An etching step prior to multi-mode adhesive resin cement increased its bond strength values and improved its penetration pattern to both enamel and dentin, also length of resin tags formed by total-etch adhesives seems not to play an important role in determining bond strength. Keywords: Resin cements, Adhesives, Multi-mode, dental substrates, bonding, interface.

Evaluation of hybrid layer thickness and resin tag length of self-etch adhesives with different ph using confocal laser scanning microscope: an in vitro study

The aim of this in vitro study is to evaluate the hybrid layer thickness and resin tag length of self-etches adhesives with different pH using Confocal Laser Scanning Microscope (CLSM). Total 40 teeth was prepared and divided into four groups. Group-I (Prime and Bond NT), group-II: (Xeno III), group-III: (Xeno V) and group-IV: (Xeno IV). Each group contains 10 teeth. The samples were mounted on Borosilicate cover glass with cover slip. The excitation laser light was generated with a wavelength 514nm. The image was recorded in fluorescent mode and hybrid layer and resin tag length were visualized as green. They were analyzed, and thickness of hybrid layer and length of resin tag were measured by means of Image Browser software (zeiss, Germany) in micrometers. Results were tabulated and mean obtained. Group-I (Prime and Bond NT) showed the maximum values for hybrid layer thickness & resin tag length compared to group-II (Xeno III), group-III (Xeno V) and group-IV (Xeno IV). Among the self-etching primer group-II (Xeno III) with strong pH (<1) gave higher values for hybrid layer thickness and resin tag length. Among the self-etching adhesives, strong self-etch adhesive showed the maximum hybrid layer thickness and resin tag length. Further studies with more parameters must be conducted to evaluate the resin-dentin interface.

Influence of erbium, chromium-doped: Yttrium scandium-gallium-garnet laser etching and traditional etching systems on depth of resin penetration in enamel: A confocal laser scanning electron microscope study.

Objective:This study was performed to assess the resin tag length penetration in enamel surface after bonding of brackets to identify which system was most efficient.Methodology:Our study was based on a more robust confocal microscopy for visualizing the resin tags in enamel. Totally, 100 extracted human first and second premolars have been selected for this study and were randomly divided into ten groups of 10 teeth each. In Group 1, the buccal enamel surface was etched with 37% phosphoric acid (3M ESPE), Group 2 with 37% phosphoric (Ultradent). In Groups 5, 6, and 7, erbium, chromium-doped: Yttrium scandium-gallium-garnet (Er, Cr: YSGG) laser (Biolase) was used for etching the using following specifications: Group 5 (1.5 W/20 Hz, 15 s), Group 6 (2 W/10 Hz, 15 s), and Group 7 (2 W/20 Hz, 15 s). In Groups 8, 9, and 10, Er, Cr: YSGG laser (Biolase) using same specifications and additional to this step, conventional etching on the buccal enamel surface was etched with 37% (3M ESPE) after laser etching. In Groups 1, 5, 6, 7, 8, 9, and 10 3M Unitek Transbond XT primer was mixed with Rhodamine B dye (Sigma-Aldrich, Germany) to etched surface and then cured for 20 s. In Group 2, Ultradents bonding agent was mixed with Rhodamine B. In Group 3, 3M Unitek Transbond PLUS, Monrovia, USA, which was mixed with Rhodamine B dye (Sigma-Aldrich, Germany). Group 4, with self-etching primer (Ultradent-Peak SE, USA) was mixed with Rhodamine B dye (Sigma-Aldrich, Germany). Later (3M Unitek, Transbond XT, Monrovia USA) [Figure 1] was used to bond the modified Begg brackets (T. P. Orthodontics) in Groups 1, 3, 5, 6, 7, 8, 9, and 10. In Groups 2, 4 Ultradent-Peak LC Bond was used to bond the modified brackets. After curing brackets were debonded, and enamel depth penetration was assessed using confocal laser scanning microscope.Results:Group J had a mean maximum depth of penetration of 100.876 μm, and Group D was the least having a maximum value of 44.254 μm.Conclusions:Laser alone groups had comparable depths of penetration to that of self-etching groups but much lower than conventional acid etched groups.

Evaluation of thickness of hybrid layer and length of resin tags of three adhesives to the root canal dentin: An in vitro scanning electron microscopic study

Objectives: This present study was done to evaluate the resin-dentin interface of three adhesive systems used for bonding the root canal under scanning electron microscopic (SEM). Materials and Methods: Sixty single-rooted human maxillary anterior teeth were decoronated at the cementoenamel junction apical preparation done up to 60 no. K-file and obturated with cold lateral compaction of gutta-percha and resin sealer (AH Plus). The specimens were then randomly divided into four groups of 15 teeth each. Group I-Etch and rinse adhesive system Group II-Self-etch adhesive system Group III-Resin modified glass ionomer adhesive system Group IV-No adhesive system used (control). All the adhesive systems were light cured then fiber posts were luted with dual cure resin cement and the specimens were prepared for SEM examination at magnifications ×1500 and ×5000 at coronal, middle and apical thirds of root canal. Results: Statistical analysis was performed using one-way ANOVA followed by post-hoc Tukey's honestly significant difference test. Group I showed highly statistical significant difference when compared with other groups. Conclusion: Maximum thickness of hybrid layer and long resin tags were shown by etch and rinse adhesives followed by self-etch adhesives.

Effect of Sodium Ascorbate on Dentin Bonding After Two Bleaching Techniques

The purpose of this study was to analyze the influence of 10% sodium ascorbate (SA) on the hybrid layer, resin tag length, and bond strength to dentin after bleaching. Six groups were tested: G C, control; G SA, sodium ascorbate (SA) + restoration; G CP, bleaching with carbamide peroxide (CP) + restoration; G CP+SA, bleaching with CP + SA+ restoration; G HP, bleaching with 35% hydrogen peroxide (HP) + restoration; and G HP+SA, HP + SA + restoration. After dental bleaching, the dentin was exposed and the antioxidant solution was applied to groups G SA, G CP+SA, and G HP+SA, before bonding procedures. The teeth were sectioned in the mesiodistal direction. One section was decalcified, and the specimens were embedded in paraffin and sectioned in the longitudinal direction with a thickness of 6 μm. Fifteen slices of each specimen were selected according to a systematic sample of slices with an interval proportional to the total number of slices obtained for each tooth. The specimens were stained using the Brown & Brenn method, and an optic microscope was used to analyze the hybrid layer thickness and resin tag length. The remaining tooth segment was sectioned into stick-shaped specimens and used for microtensile bond strength testing (0.5 mm/min). Statistical analysis was performed using two-way analysis of variance and Fisher test. The results for hybrid layer + tag formation (in micrometers) were G C, 13.27 Aa; G SA, 11.85 Ba; G CP, 6.84 Bb; G CP+SA, 9.02 Ab; G HP, 7.28 Bb; and G HP+SA, 9.22 Ab; bond strength results (in MPa) were G C, 49.5 Aa; G SA, 51.7 Aa; G CP, 37.16 Bb; G CP+SA, 47.69 Aa; G HP, 32.39 Ab; and G HP+SA, 39.67 Ab. Tooth bleaching with CP or HP impairs the formation of the hybrid layer and resin tags and reduces the microtensile bond strength. Statistically, the use of SA significantly increases the hybrid layer thickness and resin tag length. The microtensile bond strength values for carbamide peroxide increased, but the microtensile bond strength for hydrogen peroxide was not affected.