The bleaching effect of office bleaching agents containing S-PRG filler evaluated by pH value and electron spin resonance.

OBJECTIVES: Surface reaction-type pre-reacted glass-ionomer (S-PRG) filler releases six types of ions with a neutralizing ability. This study evaluated the effect of S-PRG filler incorporation in an H2O2-based bleaching material on the bleaching efficacy, pH, and reaction state. MATERIALS AND METHODS: The experimental bleaching material was formulated by the addition of 5% or 10% S-PRG fillers to the powder part. The stained bovine teeth were treated with the prepared bleaching paste. Commission internationale de l'éclairage (CIE) L*a*b* color space values were recorded before and after bleaching, and the color difference (ΔE) and whiteness index (WID) were calculated. Moreover, the used bleaching formulations were assessed for their pH values and reaction state by evaluating the oxidation state of manganese (Mn+2) using electron spin resonance (ESR). RESULTS: The results of ΔE and WID showed that the addition of S-PRG filler increased the bleaching effect, but there was no significant difference between the groups with 5% and 10% S-PRG filler. A significant increase in pH in S-PRG filler groups (5% pH 6.7, 10% pH 6.8) was found compared to the 0% group (pH 4.8). ESR measurements showed that the signal emitted from Mn+2 decreased over time. The S-PRG filler groups showed a significantly higher reduction in Mn+2 compared to the 0% group, with no significant difference between the 5% and 10% S-PRG groups. CONCLUSIONS: S-PRG filler addition resulted in improved bleaching efficacy, higher reaction rate, and pH values that are close to neutral. CLINICAL RELEVANCE: S-PRG filler addition may be effective on the bleaching outcome of H2O2-based materials.

Effect of photo-thermal acceleration on in-office bleaching.

The purpose is to evaluate the effect of photo-thermal acceleration on in-office bleaching efficiency using a bleaching agent without photocatalysts in vitro. Artificially discolored bovine lower incisors were prepared, and the mixed in-office bleaching material contained hydrogen peroxide 23% was applied by following treatment for 10 min: high-(HI group) and low-intensity LED lights (LI group), oven at 38 °C (OV group), and room temperature at 23 °C (RT group). Color was measured before and after bleaching and color difference (∆E*) was calculated. The data were statistically analyzed using a two-way ANOVA and Tukey's post hoc test. The temperature change (∆T) of applied bleaching agent in HI and LI groups was measured using a thermography and was analyzed using a T test. The bleaching procedures were repeated 6 times. Irradiation in the HI group resulted in the highest ΔE, followed by the LI group whose ΔE was significantly lower. Both irradiated modes exhibited higher ΔE compared to non-irradiated OV and RT groups which were not significantly different from each other. The average temperature rise of bleaching agents in HI and LI groups after 10 min irradiation was 15.00 °C and 11.80 °C, respectively. The effect of photo-thermal acceleration was proved for an in-office bleaching agent without photocatalysts in vitro.

Swept-source optical coherence tomographic observation on prevalence and variations of cemento-enamel junction morphology.

To investigate the prevalence of different patterns of cemento-enamel junction (CEJ) morphology under swept-source optical coherence tomography (SS-OCT). One hundred extracted human teeth were used consisting of incisors, premolars, and molars. Each sample was observed for every 500 µm circumferentially along CEJ and OCT images of the pattern were noted. Microscopic observations were done for the representative sample using confocal laser scanning microscope (CLSM) and transmission electron microscope (TEM). The OCT images exhibited four CEJ patterns: edge-to-edge (type I), exposed dentin (type II), cementum overlapping enamel (type III), and enamel overlapping cementum (type IV). The prevalence of CEJ patterns was further statistically considered for mesial, distal, buccal, and lingual surfaces. The real-time imaging by SS-OCT instantly determined CEJ morphology. CLSM and TEM observation revealed morphological features along CEJ, which corresponded to OCT images of CEJ anatomy. OCT results showed 56.8% of type I pattern predominantly found on proximal surfaces, followed by 36.5% of type II pattern on buccal and lingual surface, 6.4% of type III pattern, and 0.3% of type IV pattern. There was a significant difference in prevalence of CEJ patterns among different types of teeth, but there was no statistically significant difference among the four surfaces in each type of teeth. OCT is a non-invasive diagnostic tool to examine the CEJ patterns along the entire circumference. OCT observation revealed even minor dentin exposure that would need clinical and home procedures to prevent any symptoms.

Effect of lights with various wavelengths on bleaching by 30% hydrogen peroxide.

The objective of this study was to evaluate the bleaching effect of light sources with various wavelengths using 30% hydrogen peroxide (HP) in vitro. The hematoporphyrin-stained paper was bleached with HP and irradiated for 10 min using LED light sources with 265, 310, 365, 405, or 450 nm respectively. In control group, HP was applied for 10 min without light irradiation. The bleaching procedure was repeated two times. The L*a*b* values of the samples before bleaching and after each bleaching step were measured using a colorimeter. Color changes of specimens were then calculated and statistically analyzed. There was an interaction between light sources and time of irradiation in the color change (p < 0.05). Time and light sources significantly affected ΔE and ΔL (p < 0.05). The light source of 256 nm showed the highest bleaching effect over time followed by that of 310 nm, which were statistically different from other groups (p < 0.001). The 365 nm, 450 nm groups, and control group showed low bleaching effect visually with no significant differences in ΔE and ΔL (p > 0.05). It was concluded that the wavelengths of the light sources affected the bleaching by HP. The 310-nm light can be a potential source for bleaching.

Analysis of cariogenic biofilms by using a swept-source optical coherence tomography in vitro.

OBJECTIVE: The objective was to measure the thickness of Streptococcus mutans (S. mutans) biofilms forming in an oral biofilm reactor (OBR) by using a noninvasive swept-source optical coherence tomography (SS-OCT) system at every 4 h time interval until 20 h and analyze the correlations with the amounts of biofilms. METHODS: S. mutans biofilms were formed on square-shaped bovine enamel blocks inside an OBR. Biofilms were analyzed at every 4 h stage (4 h, 8 h, 12 h, 16 h and 20 h) using a SS-OCT system and a laser scanning confocal microscope (LSCM). The amounts of biofilms were measured at each stage by separating the water insoluble glucan (WIG) and bacterial cells. Co-relationships between the SS-OCT measured biofilm thickness and the amounts of adhered biofilms were analyzed. RESULTS: The thickness of biofilms detected on SS-OCT images at 4 h stage was 0.059 ± 0.029 (Av ± SD) mm which increased time-dependently in a linear fashion after 8 h stage and reached to 0.435 ± 0.159 mm at 20 h stage and the correlation coefficient was about 0.89. The amounts of biofilms; bacterial optical density (OD) and WIG concentration increased time-dependently were 0.035 ± 0.008 / mm2 and 10.328 ± 2.492 µg/ mm2 respectively at 20 h stage. Correlation coefficients of 0.66 between 'the amounts of bacteria' and 'biofilm thickness on OCT' and 0.67 between 'the amounts of WIG' and 'biofilm thickness on OCT' were obtained, suggesting that there was a relatively positive correlation between them. CONCLUSION: The SS-OCT can be a useful tool to measure time-dependent growth of biofilms. Further studies are needed in order to assess biofilms using SS-OCT more accurately.

Effect of phytic acid used as etchant on bond strength, smear layer, and pulpal cells.

This study aimed to evaluate the effect of phytic acid (IP6), used as etchant, on resin-dentin bond strength, smear layer removal, and the viability of pulpal cells. Flat dentin surfaces with smear layer were etched with 1% IP6 for 60, 30, or 15 s; in the control group 37% phosphoric acid (PA) was used. Dentin surfaces were rinsed, blot-dried, and bonded with an etch-and-rinse adhesive, followed by composite build-ups. The specimens were subjected to tensile testing after 24 h of water storage at 37°C, and failure modes were determined using scanning electron microscopy. The effectiveness of IP6 to remove the smear layer was observed using scanning electron microscopy. To evaluate the effect on pulpal cells, solutions of 0.1 and 0.01% IP6 and of 3.7 and 0.37% PA were prepared and rat pulpal cells were treated with these solutions for 6 and 24 h. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results demonstrated that all application times of IP6 produced bond-strength values that were significantly higher than that of the control. Phytic acid effectively removed the smear layer and plugs, thus exposing the collagen network. Phytic acid had a minimal effect on pulpal cells, whereas PA resulted in a marked decrease in their viability.

Effect of an In-Office Bleaching Agent with Surface Pre-Reacted Glass-Ionomer Filler on the Enamel Surface: A In-Vitro Study.

In-office bleaching with high concentrations of hydrogen peroxide (H2O2) agents causes undesirable alterations in the enamel. Surface pre-reacted glass-ionomer (S-PRG) filler is a functional material known for its acid-neutralizing and demineralization-inhibition properties. This study evaluates the effect of S-PRG filler incorporation in H2O2-based bleaching on the enamel surface. Bovine enamel surfaces were bleached using a bleaching paste formulated with a liquid (35% H2O2) and a powder containing 5% or 10% S-PRG filler. The surface roughness and the Vickers microhardness of the treated enamel surfaces were evaluated. The enamel surfaces were observed under a scanning electron microscope (SEM) and analyzed using energy dispersive X-ray (EDX) technology. The surfaces were challenged by citric acid and observed by SEM. The specimens bleached with the paste containing the S-PRG filler showed lower enamel surface roughness and higher microhardness values than did those bleached with the plain paste (0% S-PRG filler); meanwhile, there were no significant differences between the 5% or 10% S-PRG filler groups. The S-PRG filler groups showed enamel surface morphologies similar to those of the non-bleached enamel, according to SEM observation, and EDX analysis detected the presence of fluoride and strontium ions. The S-PRG filler groups showed a higher resistance to erosion. The S-PRG filler mitigated the detrimental effects of bleaching agents on the enamel surface and provided resistance to erosion.

Effect of Er: YAG laser irradiation with additional low energy on resin-dentin bonding and morphology of bonded interface.

OBJECTIVES: To examine the micro tensile bond strength (µTBS) and the resin-dentin interface on a laser-irradiated dentin surface using two different irradiation methods, with or without additional low-energy irradiation. METHODS: The flat bovine dentin surface was divided into three groups: i). control group (C group, no irradiation), ii) 80 mJ/pulse Er: YAG laser group (80 group), iii) 80 + 30 mJ/pulse Er: YAG laser group (80 + 30 group, with an additional 30 mJ/pulse). After the roughness of the dentin surface was recorded, Clearfil SE Bond 2 or Clearfil Universal Bond Quick (Kuraray Noritake Dental Inc., Tokyo, Japan) was applied. After the µTBS testing, the failure mode was observed. The bonded interface was assessed using Rhodamine-dye incorporated adhesives and observed by optical coherence tomography. RESULTS: The dentin surface showed opened dentinal tubules without a smear layer after irradiation. For both adhesives, the µTBS was significantly higher in 80 + 30 group than in the 80 group (p < 0.05). In the 80 group, the thickness of the adhesive layer was not uniform, and the dentin surface was occasionally in direct contact with the composite resin. The failure mode images showed that most of the fractures in the 80 group were at the sub-surface of irradiated dentin. The adhesive layers of the 80 + 30 groups were homogeneous. CONCLUSIONS: The dentin surface was rough and irregular by 80 mJ irradiation, which might result in an inadequate resin-dentin interface and the weak µTBS. The bonded integrity was mitigated by additional irradiation.

A Japanese concept of considerations for evaluation of dental materials for tooth bleaching.

Recent advances in bleaching technology, such as bleaching ingredients, have accelerated the development of tooth whitening materials to change the color of natural teeth toward a lighter or whiter shade. Some bleaching materials are used for patients in combination with auxiliary medical devices to activate the bleaching materials by a light or heat source. Bleaching ingredients can be a poisonous and deleterious substance. Some bleaching materials are used in dental offices and the others at home. In clinical development of bleaching materials, appropriate evaluation of safety and efficacy is required according to the intended use. For appropriate and swift approval of the emerging bleaching materials, guideline on evaluation of dental whitening materials was discussed in a commissioned project by the Ministry of Health, Labour and Welfare of Japan for FY2021. Here, we summarize the current principles of the premarketing evaluation of the safety and efficacy.

Effect of Water Storage and Bleaching on Light Transmission Properties and Translucency of Nanofilled Flowable Composite.

This study investigated the effect of water sorption and bleaching on light transmission properties (Straight-light transmission (G0), Light diffusion (DF) and Amount of transmitted light (AV)) and translucency parameters (TP) of nano-filled flowable composites. A total of 35 composite disks (0.5 mm thickness) were prepared using A2 shade of 5 nanofiller composites (n = 7/each); Beautifil Flow Plus X F03 (SHOFU INC), Clearfil Majesty ES Flow (Kuraray Noritake Dental), Estelite Universal Flow (EUF, Tokuyama Dental), Estelite Flow Quick (Tokuyama Dental) and Filtek Supreme Ultra Flowable Restorative (FSU, 3M ESPE). Then, they were cured by LEDs (VALO, Ultradent) on standard mood (1000 mW/cm2) for 20 s. Samples were tested for straight-line transmission (G0), diffusion (DF), the amount of transmitted light (AV) and (TP) immediately after 24 h (dry storage), after 1-week water storage and after each of the three cycles of in-office bleaching (HiLite, SHOFU INC). Result: G0, DF, AV and TP were significantly affected by different materials (p < 0.001). The AV of FSU increased significantly after the 1-week water storage, then after the second bleaching cycle (p < 0.001). The TP for EUF slightly decreased (p = 0.019) after 1-week water storage, then increased throughout bleaching. Conclusion: Ageing/bleaching conditions do not affect G0, DF, AV and TP. The compositional variation between nano-filler composites resulted in a significant difference between materials.

Application of Sulfinate Agent in Conjunction with HOCl Smear-Layer Deproteinization Improves Dentin Bonding Durability of One-step Self-etch Adhesives.

PURPOSE: To evaluate the effect of a sulfinate agent on the bonding durability of one-step self-etch adhesives (1-SEAs) to smear-layer-covered dentin deproteinized with hypochlorous acid (HOCl). MATERIALS AND METHODS: Human coronal dentin disks with a standardized smear layer were deproteinized with 100 ppm HOCl solution for 0 s (control), 15 s or 30 s. After rinsing with water for 30 s and air drying, half of the specimens were treated with a sulfinate agent (Scotchbond Universal Dual Cure Activator; SDA) prior to the application of a 1-SEA (Bond Force II [Tokuyama Dental] or Clearfil Universal Bond Quick [Kuraray Noritake]). Microtensile bond strength (µTBS) was measured after 24 h or 10,000 thermal cycles (TC). The data were analyzed by three-way ANOVA with Tukey's post-hoc tests and t-tests at the 0.05 significance level. RESULTS: The 24-h µTBS of both adhesives increased statistically significantly with the HOCl pretreatment for 15 s or 30 s (p < 0.05), but it was not statistically significantly affected by the application of SDA (p > 0.05). However, after TC, the groups treated with the combination of HOCl and SDA maintained their µTBS (p > 0.05), as opposed to untreated dentin and dentin treated with either HOCl or SDA, whose µTBS decreased significantly (p < 0.05). CONCLUSION: The application of the sulfinate agent did not statistically significantly affect the immediate bond strength of 1-SEAs, and it could not prevent a significant decrease in the bond strength to untreated dentin after thermocycling. However, the sulfinate agent significantly improved the bonding durability of 1-SEAs to HOCl smear-layer deproteinized dentin.

Differential expression of co-signal molecules and migratory properties in four distinct subsets of migratory dendritic cells from the oral mucosa.

Variations in co-signal ligand expression and cytokine production greatly influence the antigen-presenting properties of migrating DCs in regional lymph nodes (RLNs). Here we investigated DCs migrating from the oral mucosa using CD326 and CD103 antigens for discriminate CD207(+) Langerhans cells (LCs) from CD207(+) submucosal DCs (SMDCs). Similar to DCs migrating from the skin, we identified four distinct oral mucosal DC (OMDC) subsets, CD11c(hi)CD207(-)CD103(-)CD326(int)CD11b(hi) (F1; resident CD11b(hi) SMDCs), CD11c(int/lo)CD207(-)CD103(-)CD326(lo)CD11b(int/hi) (F2; newly recruited blood-derived SMDCs), CD11c(int/lo)CD207(+)CD103(+)CD326(int/hi)CD11b(lo) (CD103(+) F3; resident CD207(+) SMDCs), and CD11c(int/lo)CD207(+)CD103(-)CD326(int/hi)CD11b(lo) (CD103(-) F3; resident LCs). F1 DCs migrated rapidly after fluorescein isothiocyanate (FITC) painting and expressed notably high levels of CD86, CD273, and CD274 at an earlier time point. In contrast, CD103(-) LCs expressing the highest levels of the epithelial cell adhesion molecule CD326 accounted for a minor subset at the earlier time point, but increased slowly with CD103(+)CD207(+) SMDCs. However, their expression of CD86, CD273, and CD274 was very limited. The delayed migration and limited induction of co-signal ligands suggest that roles of OMLCs are distinct from those of the other three DC subsets. The identification of distinct subsets of OMDCs in RLNs may benefit efforts to determine the functional specialization of each subset in T cell responses against orally administrated antigens.

Materials chemistry: a synthetic enamel for rapid tooth repair.

The conventional treatment of dental caries involves mechanical removal of the affected part and filling of the hole with a resin or metal alloy. But this method is not ideal for tiny early lesions because a disproportionate amount of healthy tooth must be removed to make the alloy or resin stick. Here we describe a dental paste of synthetic enamel that rapidly and seamlessly repairs early caries lesions by nanocrystalline growth, with minimal wastage of the natural enamel.

Bonding performance of self-etch adhesives to enamel bleached with different peroxide concentrations.

The aim of this study was to evaluate the micro-shear bond strength (µSBS) of one and two steps self-etch adhesive systems after enamel bleaching with photo-activated bleaching systems of different hydrogen peroxide (HP) concentration. Occlusal enamel of forty intact human molars were flattened and assigned into four groups. GI Unbleached, GII, GIII, and GIV were bleached with Pyrenees (3.5% HP), GC TiON (20% HP), and Hi-Lite (35% HP) respectively. Enamel treatment with one and two steps self-etch adhesives (Clearfil S3 Bond- S3, and Clearfil SE Bond-SE) then micro-tubes were fixed on enamel and filled with AP-X composite (n=5). Bond was tested with the universal testing machine. Data were analyzed using two-way ANOVA and Tukey's tests at 5 % level of significance. The µSBS was significantly different between adhesives (F=154.46; p<0.05) and bleaching systems (F=77.33; p<0.05) with significant interaction. Specimens bonded with S3 shows a significantly lower µSBS than those bonded with SE (p<0.05) in all groups. For both adhesives the bleached groups demonstrate lower µSBS than unbleached except specimens bleached with Pyrenees and bonded with SE (p>0.05). A significant difference was observed between groups of the bleaching systems (p<0.05). Different peroxide concentrations photo-activated bleaching systems adversely affect µSBS of one and two steps self-etch adhesives. Low concentration system (Pyrenees) does not influence the bond strength of two steps adhesive.

Effect of pH of bleaching agent on tooth bleaching action in vitro.

This study investigated the effect of pH of bleaching agent, photo-irradiation time or application times on bleaching action using hematoporphyrin-stained papers (HSPs) and artificially stained bovine-teeth (BT). 23% H2O2 with pH 5.5, 6.0, 7.0, 8.0 and 9.0 were applied on the specimens. HSP was photo-irradiated for 1, 3 and 5 min. BT were photo-irradiated for 10 min and the bleaching was repeated ten times (n=10). CIE L*a*b* of the specimens were measured before and after the procedure. Data were analyzed by repeated-measures ANOVA followed by multiple comparisons with Bonferroni correction. For the HSP, longer irradiation time and higher pH yielded significantly higher color difference (ΔE). As for BT, increasing application times and higher pH resulted in higher ΔE. It was concluded that the pH of the bleaching agent significantly improved the bleaching effect with increased photo-irradiation time for HSP and with an increase of repeated application times for BT.

The effect of in-office bleaching materials with different pH on the surface topography of bovine enamel.

This study evaluated the alterations of surface topography of the bovine enamel caused by different pH of in-office bleaching agents. 23% H2O2 with pH 5.5, 7.0 and 8.5 were applied on the bovine tooth specimens (n=10) and photo-irradiated for 10 min. The bleaching procedure was repeated three times and specimens were subjected to linear surface roughness (Ra) and Vickers microhardness test (VHN) at baseline and after three consecutive applications. The morphological alterations were observed before and after third bleaching application. Data were analyzed by two-way ANOVA followed by Tukey's HSD. The pH of the bleaching agent significantly affects the Ra and VHN (p<0.05). Low pH yielded a significant increase in Ra and decrease in VHN. All the groups showed morphological alterations and profound effect was found in pH 5.5 group. It was concluded that the pH of the bleaching agent can affect Ra, VHN and surface morphology.

Regional ultimate tensile strength and water sorption/solubility of bulk-fill and conventional resin composites: The effect of long-term water storage.

The effect of long-term water storage on the regional ultimate tensile strength (UTS), water sorption (Wsp) and water solubility (Wsl) of conventional and bulk-fill resin composites at various depths was investigated. Composite specimens light-cured from one side were sectioned into beams corresponding to different depths (1-5 mm) and stored in water for 24 h, 1 week, 1 month, 6 months or 1 year. UTS increased during the first week and then gradually decreased over time, especially in deeper regions. Bulk-fill composites initially exhibited similar UTS at all depths, whereas the UTS of conventional composites at 1 mm and 5 mm differed significantly at all time points. Wsp and Wsl increased with depth and storage time, markedly at 3-5 mm after 1 month for conventional composites and after 6 months for bulk-fill composites. The signs of degradation at depths beyond 3 mm suggested that even bulk-fill composites have suboptimal properties in layers more than 3 mm in thickness.

Effect of phytic acid as an endodontic chelator on resin adhesion to sodium hypochlorite-treated dentin.

OBJECTIVES: Phytic acid (IP6), a naturally occurring agent, has been previously reported as a potential alternative to ethylenediaminetetraacetic acid (EDTA). However, its effect on adhesion to sodium hypochlorite (NaOCl)-treated dentin and its interactions with NaOCl have not been previously reported. Thus, in this study, the effects of IP6 on resin adhesion to NaOCl-treated dentin and the failure mode were investigated and the interactions between the used agents were analyzed. MATERIALS AND METHODS: Micro-tensile bond strength (µTBS) testing was performed until failure on dentin treated with either distilled water (control), 5% NaOCl, or 5% NaOCl followed with chelators: 17% EDTA for 1 minute or 1% IP6 for 30 seconds or 1 minute. The failed specimens were assessed under a scanning electron microscope. The reaction of NaOCl with EDTA or IP6 was analyzed in terms of temperature, pH, effervescence, and chlorine odor, and the effects of the resulting mixtures on the color of a stained paper were recorded. RESULTS: The µTBS values of the control and NaOCl with chelator groups were not significantly different, but were all significantly higher than that of the group treated with NaOCl only. In the failure analysis, a distinctive feature was the presence of resin tags in samples conditioned with IP6 after treatment with NaOCl. The reaction of 1% IP6 with 5% NaOCl was less aggressive than the reaction of the latter with 17% EDTA. CONCLUSIONS: IP6 reversed the adverse effects of NaOCl on resin-dentin adhesion without the chlorine-depleting effect of EDTA.

Acid resistance of dentin after erbium:yttrium-aluminum-garnet laser irradiation.

The purpose of this study was to evaluate the acid resistance of erbium:yttrium-aluminum-garnet (Er:YAG) lased sub-surface dentin using a scanning electron microscope (SEM). Dentin disks were exposed to a single pulse of Er:YAG laser irradiation at 80 mJ/pulse under water spray, with the contact sapphire tip vertical to the dentin surfaces (n = 15). Five specimens from the laser-ablated dentin surfaces were observed. Ten specimens were crosscut, exposing the center of the lased point. For five of the specimens, the sub-surface of the lased dentin, with or without 10% phosphoric acid treatment, was evaluated. We used the remaining five specimens to analyze the degree of acid treatment on crosscut surface by observing the re-crosscut surfaces at the lased point. The irradiated dentin surfaces were irregular, scaly or flaky. Three sub-layers were observed in the sub-surface: a superficial, less decalcified layer; an intermediate most decalcified layer; and a deep, normal shade layer. Er:YAG laser irradiation affected the acid resistance of sub-surface dentin.

Effect of Er:YAG laser on dentin bonding durability under simulated pulpal pressure.

PURPOSE: To evaluate the effects of Er:YAG laser ablation on the microtensile bond strength and the nanoleakage of Er:YAG-lased dentin bonded to a self-etching adhesive system with and without pulpal pressure. MATERIALS AND METHODS: Twenty flat dentin surfaces were obtained from extracted molars. Ten specimens were irradiated by Er:YAG laser, other specimens (control group) were ground using #600 SiC paper. Direct communication to the pulp chamber was created by cutting at a level approximately 1 mm below the cementoenamel junction and parallel to the occlusal surface. The experimental groups were exposed to a simulated pulpal pressure of 15 cm H2O. Each specimen was restored using an adhesive and a photocured composite. The specimens were then sectioned vertically to obtain dentin/adhesive slabs. Ninety-six slabs were prepared for microtensile bond testing. Sixty-four slabs were immersed in ammoniacal silver nitrate tracer solution for 18 h, then rinsed thoroughly, and immersed in photodeveloping solution for 6 h prior to their examination by FE-SEM. RESULTS: The method of dentin preparation and the pulpal pressure storage condition significantly affected the microTBS, while the storage duration did not (p < 0.05). The nanoleakage patterns observed in the dentin/bond interface differed depending on whether the dentin was conventionally prepared or ablated by Er:YAG laser. CONCLUSION: Er:YAG laser ablation to dentin adversely affected the microTBS and the sealing ability of SE Bond bonded to dentin under simulated pulpal condition.