Clearfil Tri-S Bond Research Articles

Comparative evaluation of bonding performance between universal and self-etch adhesives: In vitro study

ObjectiveThis work aimed to assess the bonding performance of universal adhesive and self-etch adhesives, and a comparative study was conducted using the same acid etching mode. MethodsThe selective acid-etching mode was used to simulate bonded restorations to teeth defects of isolated human molars including enamel and dentin. Microtensile bond strength and microleakage of all adhesives were tested and compared after 24 h and 5000 thermocycles, respectively. The morphology of the adhesive interfaces was observed by scanning electron microscopy (SEM) and fluorescent staining. ResultsThe bond strength and microleakage of Single Bond Universal (SBU) adhesive are comparable to those of self-etch adhesives, although Clearfil Tri-S Bond (S3) exhibited significantly lower bond strength compared to other two self-etch groups evaluated. No significant differences were found in the microleakage resistance of these four adhesives, suggesting their similar effectiveness in sealing the margins of the restorations, although SBU showed the highest resistance of microleakage. The SEM and fluorescent staining results of the resin-dentin interfaces further revealed the formation of abundant resin tags for all adhesives. ConclusionsSelf-etch adhesives evaluated in this study performed similarly to universal adhesives in selective acid-etch mode for bond strength and microleakage resistance. Both types of adhesives exhibited effective penetration capabilities into the dentinal tubules. Clinical significanceDuring the adhesion processes involving both dentin and enamel, self-etch adhesives can serve as alternatives to universal adhesives in selective acid-etch mode.

The Various Silane Agents in Universal Adhesives on Repair Strength of Resin Composite to Resin Composite

The aim of this investigation was to examine the bonding efficacy of a universal adhesive containing various silane agents to repair aged resin composite with new resin composite. Ninety resin composite specimens were created with nanofilled resin composite and aged for 5000 cycles in a thermocycler. The specimens were sorted into nine groups (n = 10) at random based on the methods used to treat the surfaces with/without silane agent (Si), and adhesive agents (Single bond universal, SU; Single bond universal plus, SUP; Clearfil Tri-S bond universal, CFU; and Single bond 2, SB2). A template was placed on the treated surface of the aged resin composite, and then the resin composite was filled into the template. The shear bond strength (SBS) test was conducted using a universal tester and failure patterns were determined. The statistical analysis was performed using a one-way ANOVA and a Tukey’s test. The lowest SBS values were exhibited in the no surface treatment group (7.69 ± 2.57 MPa). The highest SBS values were exhibited in Si + SUP group (28.04 ± 1.62 MPa), with a significant difference compared to SUP group (22.69 ± 2.21 MPa), Si + SU group (22.08 ± 1.83 MPa), Si + CFU group (21.98 ± 1.54 MPa), and Si + SB2 group (21.85 ± 2.18 MPa). The experimental group demonstrated a predominance of adhesive failure at the junctions between the aged resin composite and the new resin composite. In conclusion, The SUP, which incorporates 3-(aminopropyl)triethoxysilane (APTES) and 3-methacryloxypropyltriethoxysilane (3-MPTES), has a positive effect on the repaired shear bond strength of resin composite to resin composite both with and without the use of a silane agent prior to the use of the SUP when compared with a conventional adhesive agent (SB2) and other universal adhesives (SU and CFU). Moreover, an additional silane agent used prior to the SUP application has the highest shear bond strength.

Evaluation of the effects of different types of adhesives on enamel demineralization during fixed orthodontic treatment

Aim: This randomised controlled split-mouth study was aimed to evaluate and compare the efficacy of a fluoride-containing adhesive (Clearfil Tri-S Bond Plus, Kuraray Noritake, Otemachi, Japan) and a conventional adhesive (3M Unitek Transbond XT, Maplewood, USA) on enamel demineralisation in orthodontically treated patients. Methods: Sixteen healthy patients who had need for correction of dental crowding were included in the study. Bracket bonding was performed using different adhesives (fluoride-containing and conventional) at random for opposite half jaw in a split-mouth design. 190 control, 190 experimental teeth were examined for bracket failure, gingival index, plaque index and enamel mineralisation parameters. Enamel mineralisation levels for each tooth for pre- and post-treatment time periods were examined using ICDASII (International Caries Detection and Assessment System) criteria and the DIAGNOdent Pen (KaVo, Biberach, Germany). Results: DIAGNOdent scores were statistically higher in the left half jaw which were control group (C) in left handed patients (p=0.038), while the scores were found to be significantly higher in the right handed patient which ipsilateral jaw were experimental group (E) (p=0.003). Conclusions: The effect of fluoride-containing adhesive on enamel demineralization and WSL (white spot lesion) formation was found to be no different than the conventional adhesive.

FARKLI HASSASİYET GİDERİCİLERİN VE ER, CR: YSGG LAZER İLE KOMBİNASYONLARININ DENTİN TÜBÜLLERİ ÜZERİNE VE DENTİNE MAKASLAMA BAĞLANMA DAYANIMINA ETKİSİ

AIM: The aim of this in vitro study was to investigate the effectiveness of Sodium Fluoride, Propolis and Er,Cr:YSGG laser alone and in combination with laser applications on dentin tubules by SEM and to examine the effects of these applications on the shear bond strength (SBS) of a universal adhesive to dentin. METHODS: Dentin samples obtained by removing the buccal enamel of 72 caries-free permanent, mandibular third molars were randomly divided into six groups (n:12): Control, Sodium Fluoride (Enamelast, Ultradent), Propolis (Fanus Propolis), Er,Cr:YSGG Laser (Biolase, Waterlase), Enamelast-Er,Cr:YSGG Laser, Propolis-Er,Cr:YSGG Laser. While the agents were applied to the dentin surfaces in the agents alone groups, laser was applied after the agent applications in the combination groups. No application was performed to the control group. After storing the samples in artificial saliva for 14 days, Clearfil Tri-S Bond Universal (Kuraray) and composite resin (Estelite Sigma Quick, Tokuyama) were applied to their surfaces. SBS tests were conducted using the Universal Tensile-Compression Test System (Instron 3382, USA). The tubule plugging efficiencies of the agents were examined on two dentin samples from each group by SEM. One-way analysis of variance (One-way ANOVA) was performed for statistical analysis of the data. For p<0.05, the results were considered statistically significant. RESULTS: No statistically significant difference was found in any comparison between all the test groups (p>0.05). In SEM examinations, occluded dentinal tubules were observed more frequently in the groups where the applications were performed in combination with laser, compared to the application of the agents alone. In the propolis group too, the tubules were usually closed, as well as open dentin tubules. CONCLUSIONS: Although combination applications of Er,Cr:YSGG Laser with Sodium Fluoride and Propolis showed greater dentin tubule plugging efficiency, these applications did not have a negative effect on the SBS of Clearfil Tri-S Bond Universal compared to the control group. The changes caused by the laser application on the dentin surface and the content of adhesive system may have prevented the SBS from being adversely affected.

Effects of C-factor on dentin bonding using various adhesive systems.

This study evaluated the effect of C-factor on the bond strength of a resin composite to floor and wall dentin using various adhesive systems. Four dentin substrates (flat wall, flat floor, cavity wall, or cavity floor) were prepared on human molars. Each specimen was restored with one of three adhesives; Clearfil SE Bond, Single Bond, or Clearfil tri-S Bond followed by buildup or filling using Z100 resin composite. The specimen was cut perpendicular to the bonded surface parallel to the floor or wall to obtain beams after light curing at 24,000 mJ/cm2. The microtensile bond strength to wall specimens or the cavity floor was determined. Data were analyzed. All adhesive systems exhibited the highest bond strength to flat wall group (p < 0.05). The bond strength to the cavity group was significantly lower than that to the respective flat group regardless of the bonding system (p < 0.05). There was no significant difference in bond strength with Clearfil SE Bond and Clearfil tri-S Bond between the cavity wall and cavity floor (p > 0.05). The findings suggested that the strength of bonding to the cavity floor and cavity wall was affected by C-factor regardless of the adhesive system. Bonding to flat wall was higher than flat floor regardless of the adhesive system. Self-etching system provided uniform bond to the cavity wall and cavity floor dentin. However, total etching system reduced bond to the cavity floor than to the cavity wall.

Effects of dentin surface preparations on bonding of self-etching adhesives under simulated pulpal pressure.

ObjectivesThis study evaluated the effects of different smear layer preparations on the dentin permeability and microtensile bond strength (µTBS) of 2 self-etching adhesives (Clearfil SE Bond [CSE] and Clearfil Tri-S Bond Universal [CTS]) under dynamic pulpal pressure.Materials and MethodsHuman third molars were cut into crown segments. The dentin surfaces were prepared using 4 armamentaria: 600-grit SiC paper, coarse diamond burs, superfine diamond burs, and carbide burs. The pulp chamber of each crown segment was connected to a dynamic intra-pulpal pressure simulation apparatus, and the permeability test was done under a pressure of 15 cmH2O. The relative permeability (%P) was evaluated on the smear layer-covered and bonded dentin surfaces. The teeth were bonded to either of the adhesives under pulpal pressure simulation, and cut into sticks after 24 hours water storage for the µTBS test. The resin-dentin interface and nanoleakage observations were performed using a scanning electron microscope. Statistical comparisons were done using analysis of variance and post hoc tests.ResultsOnly the method of surface preparation had a significant effect on permeability (p < 0.05). The smear layers created by the carbide and superfine diamond burs yielded the lowest permeability. CSE demonstrated a higher µTBS, with these values in the superfine diamond and carbide bur groups being the highest. Microscopic evaluation of the resin-dentin interface revealed nanoleakage in the coarse diamond bur and SiC paper groups for both adhesives.ConclusionsSuperfine diamond and carbide burs can be recommended for dentin preparation with the use of 2-step CSE.

The Durability of Zirconia/Resin Composite Shear Bond Strength using Different Functional Monomer of Universal Adhesives.

This study examined the effectiveness of different functional monomers in universal adhesives on zirconia/resin composite bond strength both before and after thermocycling. Four universal adhesives (G-premio bond universal, GPU; Clearfil Tri-S bond universal, CTB; Optibond Universal, OBU; Tetric N-bond universal; TNU), one adhesive (single bond 2; SB2), and one ceramic primer (Clearfil ceramic primer plus, CCP) were used in this study. Zirconia discs were prepared and embedded in acrylic. Specimens were polished and sandblasted with alumina. The specimens were randomly divided into two groups (24 hours and the thermocycled), and each group was divided into six subgroups (n = 10), according to zirconia surfaces treatments: no Tx, CCP + SB2, GPU, CTB, OBU, TNU. An Ultradent mold was located on top of the treated zirconia surface. The resin composite was filled into the mold and then light-cured. A universal testing device was used to determine the shear bond strength. The data were statistically analyzed using one-way ANOVA and Tukey's test. After water storage for 24 hours, the shear bond strengths were GPU > CCP + SB2 = CTB = OBU = TNU > no Tx (p < 0.05). After thermocycling, the shear bond strengths were CCP + SB2 = GPU = CTB = TNU > OBU > no Tx (p < 0.05). The universal adhesives containing 10-MDP exhibited the best performance in the shear bond strength of the zirconia/resin composite interface both before and after thermocycling.

The Effect of Thermocycling on Interfacial Bonding Stability of Self-Etch Adhesives: OCT Study.

Objective The aim of this study was to monitor the behavior of interfacial gaps formed under different bonded polymeric restorations before and after thermocycling (TC), using swept-source optical coherence tomography (SS-OCT) and confirming the obtained findings with confocal laser scanning microscopy (CLSM). Materials and Methods Cylindrical class I cavities were prepared in twenty noncarious human premolar teeth (1.5 mm depth × 3.5 mm diameter) and divided randomly into two groups: TS and SN, according to the adhesive system (n = 10). In the TS group, one-step self-etch adhesive Clearfil Tri-S Bond Plus (Kuraray Noritake Dental, Japan) was used, followed by composite restoration using Estelite Sigma Quick (Tokuyama Dental, Japan). In the SN group, the cavities were restored with the two-step self-etch/composite silorane-based resin restoration system (3M ESPE, USA). All specimens were restored in bulk filling technique and cured in accordance with the manufacturers' instructions. Both groups were imaged under SS-OCT after 24 h and recorded as controls. Then, each group was subjected to thermal challenge using the TC machine (5–55°C) and B-scans were recorded at different TC intervals (2600, 5200, and 10000). In order to confirm the SS-OCT findings, additional specimens were prepared, scanned, and sectioned for CLSM observation. Results B-scans demonstrated white clusters at the tooth-resin interface that corresponded to the gap location on CLSM images. The TS group showed significantly less gap formation than the SN group before and after TC (p < 0.001). Conclusions An optimal composite adaptation can be achieved when the bonded restoration comprises a combination of an adhesive containing 10-MDP monomer and a considerable highly filled composite.

Interface between calcium silicate cement and adhesive systems according to adhesive families and cement maturation.

ObjectivesThis study aimed to evaluate the interface between a calcium silicate cement (CSC), Biodentine and dental adhesives in terms of sealing ability.Materials and MethodsMicroleakage test: 160 standardized class II cavities were prepared on 80 extracted human molars. The cavities were filled with Biodentine and then divided into 2 experimental groups according to the time of restoration: composite resin obturation 15 minutes after Biodentine handling (D0); restoration after 7 days (D7). Each group was then divided into 8 subgroups (n = 5) according to the adhesive system used: etch-and-rinse adhesive (Prime & Bond); self-etch adhesive 2 steps (Optibond XTR and Clearfil SE Bond); self-etch adhesive 1 step (Xeno III, G-aenial Bond, and Clearfil Tri-S Bond); and universal used as etch-and-rinse or self-etch (ScotchBond Universal ER or SE). After thermocycling, the teeth were immersed in a silver nitrate solution, stained, longitudinally sectioned, and the Biodentine/adhesive percolation was quantified. Scanning electron microscopic observations: Biodentine/adhesive interfaces were observed.ResultsA tendency towards less microleakage was observed when Biodentine was etched (2.47%) and when restorations were done without delay (D0: 4.31%, D7: 6.78%), but this was not significant. The adhesives containing 10-methacryloyloxydecyl dihydrogen phosphate monomer showed the most stable results at both times studied. All Biodentine/adhesive interfaces were homogeneous and regular.ConclusionsThe good sealing of the CSC/adhesive interface is not a function of the system adhesive family used or the cement maturation before restoration. Biodentine can be used as a dentine substitute.

Does lining class-II cavities with flowable composite improve the interfacial adaptation?

The objective of this study was to assess in-vitro interfacial cavity adaptation of different adhesive/composites systems in class-II restoration using SS-OCT and to confirm the findings with a confocal laser scanning microscope (CLSM). Standardized rectangular-shaped class-II cavities were prepared on 24 extracted human molar teeth, bonded with adhesive and lined with flowable composite. Cavities were further restored by bulk filling using packable composite. Specimens were divided into four groups (n = 7) according to restorative materials used; PrimeFil with Estelite Posterior composites (PF; Tokuyama Dental), Clearfil Tri-S Bond Plus with Majesty LV flowable and Majesty Posterior composites (TS; Kuraray Noritake Dental), Adper Easy bond with Filtek Z350 XT flowable and Filtek Z350 XT packable composites (AE; 3 M ESPE) or Palfique Bond adhesive with Estelite Flow Quick flowable and Estelite Posterior composites (BF; Tokuyama Dental). To evaluate the cavity adaptation of these restorative materials, tomographic images of pulpal (P) and gingival (G) walls were obtained by SS-OCT with a central wavelength of 1330 nm, followed by cross-sectioning and CLSM observation to confirm OCT findings. The results showed a significant increase in the backscattered reflection was attributed to the interfacial gaps. AE groups demonstrated the highest interfacial adaptation percentage (p < 0.05), while TS and PF groups showed no significant difference (p > 0.05). BF group presented the least adaptation percentage, and the gaps were frequently observed at the adhesive/composite interface. In addition to the sensitivity of the SS-OCT to the interfacial gaps, the success of flowable lining relies on the interactions between the adhesive/tooth and adhesive/composite substrates.

Effect of smear layer and surface roughness on resin-dentin bond strength of self-etching adhesives.

The purpose of this study was to evaluate the effect of surface roughness and smear layer on the micro-shear bond strength (µSBS) of two self-etching adhesives, Clearfil SE Bond (SE) and Clearfil Tri-S Bond (S3). Flat dentin surfaces were prepared with SiC papers (600-, 180- and 120-grit) and diamond burs (extra fine, medium and coarse). They were further divided into smear-covered and smear-free surfaces and bonded with respective adhesives. µSBS test was performed after water storage at 37ºC for 24 h. Smear layer thickness measurement was evaluated by scanning electron microscope (SEM). Surface roughness was examined by contact stylus profilometer. Smear layer thickness and surface roughness were significantly different among all groups (p<0.05). No difference in µSBS was observed among surface prepared by SiC whereas bur-cut smear layer had negative effect on µSBS, especially for S3. Surface roughness from different surface preparations had no influence on µSBS (p<0.05).

Effect of the demineralisation efficacy of MDP utilized on the bonding performance of MDP-based all-in-one adhesives

ObjectivesThe amounts of calcium salt of 10-methacryloyloxydecyl dihydrogen phosphate (MDP-Ca salt) and dicalcium phosphate dihydride (DCPD) with an amorphous phase produced by the demineralisation of enamel and dentin were determined using commercial MDP-based 2-hydroxyethyl methacrylate (HEMA)-containing and HEMA-free all-in-one adhesives. The effect of the amount of MDP-Ca salt produced on bonding performance to enamel and dentin was then characterized. MethodsThree types of commercial HEMA-containing adhesives (Scotchbond Universal Adhesive, Clearfil Tri-S Bond ND, Clearfil Tri-S Bond ND Quick), a commercial HEMA-free adhesive (G-Bond Plus) and an experimental HEMA-free adhesive were used. The reactant residues of each adhesive were prepared after interacting with enamel and dentin samples for 60 s. The amounts of MDP-Ca salt and amorphous DCPD produced were determined using a phosphorous-31 nuclear magnetic resonance technique. Enamel and dentin bond strengths were measured for each adhesive, with and without thermocycling. ResultsThe amounts of MDP-Ca salt and amorphous DCPD formed after interacting with enamel and dentin differed among the five adhesives and were independent of their pH values. Enamel showed a strong positive-correlation of the bond strength of the all-in-one adhesives to the amount of MDP-Ca salt produced, however, the dentin showed a weak negative-correlation. ConclusionThe HEMA-free all-in-one adhesives showed a greater efficacy to demineralise the enamel and dentin than the HEMA-containing all-in-one adhesives. The dentin showed a different effect of the amount of MDP-Ca salt produced on the bonding performance compared with enamel. Clinical significanceThe enamel bond strength of MDP-based all-in-one adhesives strongly contributes to the demineralisation efficacy by the incorporation of MDP, in contrast to the dentin bond strength. However, the efficacy of MDP-based all-in-one adhesives to demineralise the enamel and dentin is not directly related to the pH value of the MDP-based all-in-one adhesive.

Influence of Ambient Air and Different Surface Treatments on the Bonding Performance of a CAD/CAM Composite Block.

To evaluate the bond strengths of time elapsed after sandblasting with alumina particles on a CAD/CAM composite block treated with different surface conditioning methods. A CAD/CAM composite block (CCB) was cut into 72 slices of approximately 2 mm thickness. The CCB slices were divided into three groups according to sandblasting pressure (0.1 MPa, 0.2 MPa, or untreated), and then divided into two subgroups according to the time elapsed after sandblasting: same-day or one-week dry storage under controlled laboratory conditions before cementation. Surface roughness was observed by confocal laser microscopy (CLSM) (n = 20); then the wettability of the CCB surfaces was examined using a contact angle (CA) measuring device on a droplet of deionized water (n = 12). Next, CCB slices were divided into three subgroups according to the surface treatment: Clearfil Ceramic Primer (CP), Clearfil Universal Bond (UB), or a mixture of Clearfil Porcelain Bond Activator and Clearfil tri-S Bond ND Quick (NDP). All CCB slices were then cemented with Panavia V5 and stored at 37°C in distilled water for 24 h and cut into sticks (n = 10). The sticks were subjected to microtensile bond strength (µTBS) testing, and failure mode analysis was performed using scanning electron microscopy. The µTBS results were subjected to 3-way and 2-way ANOVA (α = 0.05). All groups showed a statistically significant increase in wettability accompanied by decreased µTBS after one week; however, the UB group exhibited stable performance after one week. The time elapsed after sandblasting with alumina particles affects the bond strength, but it had no significant effect on the UB group.

Bonding performance of universal adhesives on composite repairs, with or without silane application.

Aim:This study aims to investigate the adhesive performance of three different universal adhesives to repair aged composite restorations, with or without the application of silane.Materials and Methods:A hundred and twenty resin composite samples were prepared, aged and randomly divided into 6 main Groups (single bond universal [SBU], All-Bond Universal [ABU], Futurabond U, Clearfil Tri-S Bond, Single Bond 2, and Clearfil SE Bond) and 2 subgroups (with or without silane). A microhybrid composite resin was placed on the aged composite surfaces and light cured. After a micro-shear bonding test, the fracture surfaces were examined under the scanning electron microscopy. Statistical analysis was performed using two-way ANOVA and Tukey's post hoc tests.Results:Among all the universal adhesives, SBU showed the highest bond strength values compared to the other two universal adhesives when used with and without silane (P > 0.05). Between ABU and Futurabond U, no significant difference was observed with silane (P > 0.05) and without silane (P > 0.05). Among conventional adhesives, there was no statistically significant difference (P > 0.05) both with and without silane.Conclusion:Within the limitations of this study, while SBU can be safely used with and without the application of silane, Futurabond U cannot be used without silane.

µCT-3D visualization analysis of resin composite polymerization and dye penetration test of composite adaptation.

This study evaluated the effects of the light curing methods and resin composite composition on composite polymerization contraction behavior and resin composite adaptation to the cavity wall using μCT-3D visualization analysis and dye penetration test. Cylindrical cavities were restored using Clearfil tri-S Bond ND Quick adhesive and filled with Clearfil AP-X or Clearfil Photo Bright composite. The composites were cured using the conventional or the slow-start curing method. The light-cured resin composite, which had increased contrast ratio during polymerization, improved adaptation to the cavity wall using the slow-start curing method. In the μCT-3D visualization method, the slow-start curing method reduced polymerization shrinkage volume of resin composite restoration to half of that produced by the conventional curing method in the cavity with adhesive for both composites.μCT-3D visualization method can be used to detect and analyze resin composite polymerization contraction behavior and shrinkage volume as 3D image in the cavity.

Evaluation of sub-surface penetration and bonding durability of self-etching primer systems to Er:YAG laser treated cervical dentin.

This study aimed to investigate self-etching bonding systems penetrating in sub-surface dentin layer after Er:YAG laser irradiation and micro-shear bonding durability over a period of 1 year. Dentin slices obtained from extracted human third molars were prepared. Two self-etching adhesive systems were evaluated: Clearfil SE Bond and Clearfil Tri-S Bond. Specimens were tested for micro-shear bond strength with one of the following treatments: Er:YAG laser irradiation and 600-grit silicon paper polishing at 24 h, 7 days, 6 months and 1 year. The adhesive interfaces between bonding agents and lased cervical dentin were studied. No hybrid layer could be observed for lased dentin. The slim resin tags could be seen penetrating through the lased subsurface layer. Bond strength to lased dentin after 6 months and 1 year were significantly decreased (p<0.05).

Effect of thermocycling to adhesive interface of enamel analyzed by polarized light microscopy

Objective: The less aggressive demineralization of enamel by self-etching systems results in greater staining, marginal leakage, and failure in their restorations, so this study aimed to assess the silver nitrate infiltration and tag formation of the enamel/adhesive interface. Material and Methods: Two hundred enamel fragments were randomly assigned into 10 groups according to the adhesive system (Single Bond Adper Plus-(SB), Clearfil Tri-S Bond-(CF), or Scotchbond Universal-(SBU)) and enamel surface (ground-(ge), unground-(ue), phosphoric acid etching-(pha), or none) (n=10): (SB-ue), (SB-ge), (CF-ue), (CF-ge), (CF-ue/pha), (CF-ge/pha), (SBU-ue), (SBU-ge), (SBU-ue/pha), and (SBU-ge/pha). Half of the restored samples were submitted to thermocycling. Four slices of 1.0mm/sample were obtained to evaluate tag formation and silver nitrate infiltration. All of the specimens were examined with Polarized Light Microscopy, and the percentage of infiltration was quantified. Results: No interactions were found among the three factors. The adhesive and aging exhibited an interaction. Significant differences were found only after thermocycling: the SB and SBU-etched groups had decreased infiltration compared with the other groups. The tag length after etching was higher for ge compared with ue, regardless of the adhesive system. Conclusion: The self-etching techniques resulted in significantly less tag formation compared with the conventional technique.KeywordsAdhesives; Aging; Dental enamel; Microscopy, polarization; Silver nitrate.

Effect of endodontic sealers on bond strength of restorative systems to primary tooth pulp chamber

Background/purposeAlthough current literature suggests that root canal sealers affect the bonding ability of restorative systems to pulp chamber dentin of permanent teeth, primary teeth have not been investigated. This study intended to evaluate the microtensile bond strength (μTBS) of three restorative systems to pulp chamber dentin in primary teeth and to determine the effect of two different root canal sealers on the μTBS. Materials and methodsNinety primary molars were used in this study. The teeth were randomly divided into three main groups according to canal sealers: (1) control (without sealer); (2) Metapex; and (3) zinc-oxide eugenol. The main groups were further divided into three subgroups depending on the coronal restorative system: (1) compomer (Prime Bond NT + Dyract EXTRA); (2) composite (Clearfil Tri-S Bond + Clearfil Photo Posterior); and (3) resin-modified glass ionomer (Fuji II LC). After restoration, the buccal wall of the pulp chamber was sectioned to obtain sticks (1 mm × 1 mm). The μTBS was then measured. Data were analyzed with two-way analysis of variance, followed by a posthoc test. The interfacial morphology of the bonded space was evaluated using scanning electron microscopy. ResultsIn the control group, a significant difference was observed only for the μTBS of the composite (P < 0.05). Compared with the control groups, Metapex and zinc-oxide eugenol significantly reduced the μTBS of restorative systems (P < 0.05). ConclusionComposite materials seemed to bond to pulp chamber dentin in primary teeth with a higher strength than compomer and resin-modified glass ionomer. Metapex and zinc-oxide eugenol canal filling materials reduced the bond strength of all three restorative systems.

Assessment of bacterial demineralization around composite restorations using swept-source optical coherence tomography (SS-OCT)

ObjectiveTo observe the bacterial demineralization of the enamel and dentin around composite restorations bonded with one-step and two-step self-etch adhesive systems using swept-source optical coherence tomography (SS-OCT). MethodsForty class V cavities (2.5-mm surface diameter, 2.0-mm maximum depth) were prepared on cervical areas of 20 human molars. The specimens were either treated with one-step adhesive (Clearfil Tri-S Bond ND Quick; TS) or two-step adhesive (Clearfil SE Bond; SE), restored with a flowable resin composite (Estelite Flow Quick). Specimens in the demineralized group were incubated for 2 weeks after Streptococcus mutans biofilm formation, while specimens in the control group were incubated for 2 weeks without biofilms. After SS-OCT observation, specimens were cut and examined under confocal laser scanning microscope (CLSM). The lesion depth (LD), interfacial gap depth (GD) and gap length (GL) obtained from SS-OCT and CLSM were analyzed by Pearson's correlation, LD by Independent-samples t-test, GD and GL by Welch t-test, the frequency of specimens with or without gap by Fisher's exact test at the 95% significant level. ResultsSpecimens with interfacial gaps in the demineralized group showed significantly higher frequency than that in the control group (p<0.05). There was a significant correlation between SS-OCT and CLSM values of LD, GD and GL (p<0.05). SE showed significantly larger LD of dentin, but less GD and GL of enamel than TS (p<0.05). SignificanceSS-OCT nondestructively detected demineralization around composite restorations and interfacial gaps created by S. mutans biofilm in this in vitro model.

Monitoring of cariogenic demineralization at the enamel–composite interface using swept-source optical coherence tomography

ObjectivesThe aim of this study was to evaluate enamel demineralization at composite restoration margins caused by cariogenic biofilm using swept-source optical coherence tomography (SS-OCT). MethodsSixty round-shaped cavities were prepared on the mid-buccal enamel surface of extracted human molars. The cavities were restored with Estelite Flow Quick flowable composite using either Clearfil SE Bond or Clearfil Tri-S Bond ND bonding agents. Streptococcus mutans suspension was applied to form a cariogenic biofilm on the surface. After 1, 2, or 3 weeks of incubation (n=10), the biofilm was removed to observe the carious demineralization at the cavosurface margins using SS-OCT. The gap along the enamel–composite interface was recorded on each adhesive system. Confirmatory direct observation was accomplished at the same location using confocal laser scanning microscope. ResultsThe demineralized enamel around the restorations was observed as a zone of intensified brightness in SS-OCT. The demineralized lesion on the cervical enamel was significantly deeper than that on the occlusal enamel (p<0.05). However, the extension of enamel demineralization at the enamel–composite interface was significantly deeper at the occlusal wall than the cervical wall (p<0.05). The extension in Tri-S Bond ND group was significantly deeper than in SE Bond group (p<0.05). A significant increase in gap formation was found after the extension of demineralization compared with the baseline. SignificanceThe carious demineralization around composite restorations were observed as a bright zone in SS-OCT during the process of bacterial demineralization. SS-OCT appears to be a promising modality for the detection of caries adjacent to an existing restoration.