• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.361-367
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• 2018

The purpose of this study was to evaluate the influence of hydrofluoric acid etching treatment on the bonding strength of yttria-stabilized tetragonal zirconia polycrystal(Y-TZP). Four groups of zirconia-resin cement specimens were prepared; 1) ZGS group (zirconia, no treatment), 2) ZGSH group (zirconia, hydrofluoric acid etching treatment) 3) H-ZGS group (Hybrid zirconia, no treatment) 4) H-ZGSH group (Hybrid zirconia, hydrofluoric acid etching treatment). The shear bond strength between zirconia and porcelain was measured using a Instron Universal Testing Machine(Model DBBP-500, Instron Corporation, Kyonggi, Korea). Data were statistically analyzed using independent t-test and two-way ANOVA(${\alpha}=0.05$). The ceramic-resin cement bonding strength was affected by hydrofluoric acid etching treatment(p<0.05). Digital microscope examination of the fracture surface showed mixed failures with adhesive and cohesive types in hydrofluoric acid etching treatment with treated zirconia and hybrid zirconia groups.

• The Journal of Advanced Prosthodontics
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• v.12 no.5
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• pp.291-298
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• 2020

PURPOSE. The aim of this study is to evaluate the influence of repeated surface treatments on wettability and surface roughness for zirconia surface and bond strength of zirconia-based ceramics to resin cement. MATERIALS AND METHODS. Seventy blocks (10 × 10 × 3 mm) of zirconia-based ceramics were fabricated and divided into two groups according to the surface treatments: (A) 110 ㎛ Al₂O₃ airborne-particle abrasion and (R) 110 ㎛ silica modified Al₂O₃ airborne-particle abrasion. At stage 2, each group was subdivided into 5 groups according to the surface retreatments: (a) 110 ㎛ Al₂O₃ airborne-particle abrasion, (r) 110 ㎛ silica modified Al₂O₃ airborne-particle abrasion, (D) diamond bur, (Da) diamond bur + 110 ㎛ Al₂O₃ airborne-particle abrasion, and (Dr) diamond bur + 110 ㎛ silica modified Al₂O₃ airborne-particle abrasion. Cylinders of self-adhesive resin cement were cemented onto each treated ceramic surface and subjected to micro-shear bond strength test. Additional specimens were prepared for roughness and wettability analyses. The data were subjected to t-test and One-way ANOVA followed by Tukey's post hoc test (α=.05). RESULTS. At stage 1, group R presented higher bond strength values than group A (P=.000). There was a statistically significant increase of bond strength at stage 2 for group A (P=.003). The diamond bur influenced the surface roughness, increasing the values (P=.023). Group R provided better wettability. Regardless of the applied surface treatment, most of failures were adhesive. CONCLUSION. The combination of application and reapplication of Rocatec Plus showed the best results of bond strength. Surface retreatment and recementation might be an indicated clinical strategy.

• The Journal of Advanced Prosthodontics
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• v.5 no.1
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• pp.16-20
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• 2013

PURPOSE. To assess the retention of glass fiber post cemented with self-adhesive resin cement into optimum and over-prepared root canals following obturation in the presence of either eugenol (EB) or calcium hydroxide (CB)-based sealers. MATERIALS AND METHODS. Roots of extracted premolars were endodontically-treated in 5 groups (n = 10). Roots of Group 1 (control) were left with no obturation and then optimally prepared to receive endodontic dowels. Other root canals were obturated with gutta-percha in the presence of either eugenol-based (Groups 2 and 4) or calcium hydroxide-based (Groups 3 and 5) sealer. Dowel spaces were prepared with optimal diameter in Groups 2 and 3, one size larger in Groups 4 and 5. Standardized fiber posts were luted to the prepared spaces using self-adhesive resin cement and its retention was then tested on an universal testing machine. Both one-way ANOVA and Tukey's HSD comparisons (${\alpha}$=0.05) were used to identify the significance of inter-group retention differences. Scanning electron microscopy (SEM) of both optimally and over-prepared dowel spaces was also considered to figure the nature of their interior out. RESULTS. The post retention was significantly higher to the non-obturated, optimally-prepared dowel spaces of Group 1 compared to the obturated, optimally-prepared ones of Groups 2 and 3. For each dowel space diameter, root canals obturated using CB of Groups 3 and 5 showed significantly higher dowel retention compared to those obturated using EB of Groups 2 and 4. Post retention to the over-prepared dowel spaces of Groups 4 and 5 was significantly higher than that recorded for the optimally-prepared ones of Groups 1-3. SEM images revealed traces of endodontic sealer and gutta-percha on the walls of the optimally-prepared dowel spaces. CONCLUSION. Despite the adverse effect of endodontic sealers on the retention of fiber posts, the over-preparation of dowel spaces helps to improve the retention.

• The Journal of Advanced Prosthodontics
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• v.13 no.4
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• pp.237-245
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• 2021

PURPOSE. This study aimed to compare the microshear bond strength (µSBS) of dual-cure resin cement in CAD-CAM zirconia after different cleaning techniques. MATERIALS AND METHODS. Fifty discs of zirconia-based ceramic from Ivoclar Vivadent were embedded in acrylic resin. The discs were divided into five groups according to the cleaning methods used: Group 1: drying with spraying + sandblasting with Al₂O₃; Group 2: washed with water and dried with spraying + sandblasting with Al₂O₃;Group 3: washed with distilled water and dried with spraying + sandblasting with Al₂O₃ + zirconium oxide (Ivoclean); Group 4: washed with distilled water and dried with spraying + sandblasting with Al₂O₃ + potassium hydroxide (Zirclean); and Group 5: washed with distilled water and dried with spraying + sandblasting with Al₂O₃ + 1% NaClO. All of the groups were contaminated with artificial saliva for 1 minute and then cleaned. Statistical analyses were performed using ANOVA and Tukey's tests. RESULTS. There were statistically significant differences among all groups for µSBS (P < .05). The group treated with zirconium oxide (Group 3) showed the highest µSBS (18.75 ± 0.23 MPa). CONCLUSION. When applied to zirconia, the cleaning methods affected the bonding with resin cement differently.

• Restorative Dentistry and Endodontics
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• v.48 no.3
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• pp.30.1-30.11
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• 2023

Objectives: This study verified the possibility of cementing fiberglass-reinforced posts using a flowable bulk-fill composite (BF), comparing its push-out bond strength and microhardness with these properties of 3 luting materials. Materials and Methods: Sixty endodontically treated bovine roots were used. Posts were cemented using conventional dual-cured cement (CC); self-adhesive cement (SA); dual-cured composite (RC); and BF. Push-out bond strength (n = 10) and microhardness (n = 5) tests were performed after 1 week and 4 months of storage. Two-way repeated measures analysis of variance (ANOVA), 1-way ANOVA, t-test, and Tukey post-hoc tests were applied for the push-out bond strength and microhardness results; and Pearson correlation test was applied to verify the correlation between push-out bond strength and microhardness results (α = 0.05). Results: BF presented higher push-out bond strength than CC and SA in the cervical third before aging (p < 0.01). No differences were found between push-out bond strength before and after aging for all the luting materials (p = 0.84). Regarding hardness, only SA presented higher values measured before than after aging (p < 0.01). RC and BF did not present 80% of the maximum hardness at the apical regions. A strong positive correlation was found between the luting materials' push-out bond strength and microhardness (p < 0.01, R² = 0.7912). Conclusions: The BF presented comparable or higher push-out bond strength and microhardness than the luting materials, which indicates that it could be used for cementing resin posts in situations where adequate light curing is possible.

• Restorative Dentistry and Endodontics
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• v.48 no.3
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• pp.28.1-28.13
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• 2023

Objectives: This study aimed to investigate the effect of the application method of 2% chlorhexidine (CHX) and its influence on the adhesion of fiberglass posts cemented with a self-adhesive resin cement. Materials and Methods: Sixty human mandibular premolars were endodontically treated and divided into 5 groups (n = 12), according to the canal irrigant and its application method: 2 groups with conventional syringe irrigation (CSI)-2.5% sodium hypochlorite (NaOCl) (control) and 2% CHX- and 3 groups with 2% CHX irrigation/activation-by passive ultrasonic irrigation (PUI), Easy Clean file, and XP-Endo Finisher file. Two roots per group were evaluated for smear layer (SL) removal by scanning electron microscopy. For other roots, fiber posts were luted using a self-adhesive resin cement. The roots were sectioned into 6 slices for push-out bond strength (BS) (7/group) and nanoleakage (NL) (3/group). Data from SL removal were submitted to Kruskal-Wallis and Student-Newman-Keuls tests (α = 0.05). Data from BS and NL were evaluated by 2-way analysis of variance and Tukey's test (α = 0.05). Results: For SL removal and BS, the CHX irrigation/activation promoted better values than CSI with CHX (p < 0.05), but it was not significantly different from CSI with NaOCl (p > 0.05). For NL, the lowest values were obtained by the chlorhexidine irrigation/activation groups (p < 0.05). Conclusions: Active 2% CHX irrigation can be used to improve the post space cleaning and adhesion before fiber post cementation with self-adhesive resin cements.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.3
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• pp.253-265
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• 2011

When restoring endodontically treated teeth is the mismatch between fiber post size and post space diameter, the resin cement layer is excessively thick in post space and voids are likely to form in it, thus predisposing to de-bonding. The method to overcome this problem is to reline the fiber post with composite resin. This individual anatomic post improves the adaptation of post to root walls and decreases the resin cement thickness. The purpose of this in vivo study was to evaluate the push-out bond strength of fiber post according to relining procedure and luting agents type used for simplicity of clinical procedure. Forty-two extracted teeth were divides into six groups.(n=7) A1: relined fiber post cemented with Luxacore/all-bons 2, A2: non-relined fiber post cemented with Luxacore/all-bond2, B1: relinind fiber post cemented with Calibra/XP-bond, B2: non-relined fiber post cemented with Calibra/XP-bond, C1: relined fiber post cemented with RelyX Unicem, C2: non-relined fiber post cemented with RelyX Unicem Push-out bond strength was affected by interaction between relining procedure and luting agent type. Relined fiber post presented higher push-out bond strength value than non-relined fiber post and statically significant differences(p<0.05) Cementation with RelyX Unicem showed significantly higher bond strength than other luting agents(p<0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.354-363
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• 2016

Purpose: The aim of this study was to investigate whether the application of nano-structured alumina coating to the surface of Y-TZP could enhance the bond strength with resin cement. Materials and methods: A total of 80 zirconia plates were prepared and divided into four groups. : 1) airborne particle abrasion treatment (A) : 2) Rocatec treatment after airborne particle abrasion (R) : 3) nano-structured alumina coating treatment after polishing (PC) and 4) nano-structured alumina coating after airborne particle abrasion (AC). Alumina coating was formed by the hydrolysis of aluminium nitride (AlN) powder and heat treatment at $900^{\circ}C$. Coating patterns were observed with FE-SEM. Resin block was bonded to treated zirconia ceramics using resin cement. The shear bond strengths were measured before and after thermocycling. Results: The FE-SEM images show a dense and uniform nano-structured alumina coating structure, which enhances shear bond strength by increasing micro mechanical interlocking to resin cement. PC and AC groups showed higher shear bond strengths than A and R groups before and after thermocycling. A and R groups displayed significant drops in shear bond strength after thermocycling. However, PC and AC groups did not show any meaningful decreases in shear bond strength after thermocycling. Conclusion: Treatment of Y-TZP ceramics with nano-structured alumina coating could significantly increase their shear bond strength.

• Restorative Dentistry and Endodontics
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• v.30 no.4
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• pp.283-293
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• 2005

The purpose of this study was to evaluate the effect of dual bonding technique by comparing microshear bond strength between two different luting methods of resin cement to tooth dentin. Three dentin bonding systems(All-Bond 2, One-Step, Clearfil SE Bond), two temporary cements (Propac, Freegenol) were used in this study. In groups used conventional luting procedure, dentin surfaces were left untreated. In groups used dual bonding technique, three dentin bonding systems were applied to each dentin surface. All specimens were covered with each temporary cement. The temporary cements were removed and each group was treated using one of three different dentin bonding system. A resin cement was applied to the glass cylinder surface and the cylinder was bonded to the dentin surface. Then, micro-shear bond strength test was performed. For the evaluation of the morphology at the resin/dentin interface, SEM examination was also performed. 1. Conventional luting procedure showed higher micro-shear bond strengths than dual boning technique. However, there were no significant differences. 2. Freegenol showed higher micro-shear bond strengths than Propac, but there were no significant differences. 3. In groups used dual bonding technique, SE Bond showed significantly higher micro-shear bond strengths in One-Step and All-Bond 2 (p<0.05), but there was no significant difference between One-Step and All-Bond 2. 4. In SEM observation, with the use of All-Bond 2 and One-Step, very long and numerous resin tags were observed. This study suggests that there were no findings that the dual bonding technique would be better than the conventional luting procedure.

• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.343-355
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• 2007

The objectives of this study was to evaluate the durability of 4 resin cements by means of microtensile bond strength test combined with thermocycling method and fractographic FE-SEM analysis. Experimental groups were prepared according to thermocycling (0, 1,000, 5,000) and the kind of resin cements, those were Variolink II, Multilink, Panavia F 2.0, Rely X Unicem. Flat dentin surfaces were created on mid-coronal dentin of extracted third molars. Then fresh dentin surface was grounded with 320-grit silicon carbide abrasive papers to create uniform smear layers. Indirect composite block (Tescera, Bisco Inc., Schaumburg, IL, USA) was fabricated ($12\;{\times}\;12\;{\times}\;6\;mm^3$). It's surface for bonding to tooth was grounded with silicon carbide abrasive papers from 180- to 600-grit serially, then sandblasted witk $20\;-\;50\;{\mu}m$ alumina oxide. According to each manufacturer's instruction, dentin surface was treated and indirect composite block was luted on it using each resin cement. For Rely X Unicem, dentin surface was not treated. The bonded tooth-resin block were stored in distilled water at $37^{\circ}C$ for 24 hours. After thermocycling, the bonded tooth-resin block was sectioned occluso-gingivally to 1.0 mm thick serial slabs using all Isomet slow-speed saw (Isomet, Buehler Ltd, Lake Bluff, IL, USA). These sectioned slabs were further sectioned to $1.0\;{\times}\;1.0\;mm^2$ composite-dentin beams. The specimens were tested with universal testing machine (EZ-Test, Shimadzu, Japan) at a crosshead speed of 1.0 mm/min with maximum load of 500 N. The data was analyzed using one-way ANOVA and Duncan's multiple comparison test at $p\;{\leq}\;0.05$ level. Within the limited results, we conclude as follows; 1. The bond strength of Variolink II was evaluated the highest among experimental groups and was significantly decreased after 1,000 thermocycling (p < 0.05). 2. The bond strength of Multilink was more affected by thermocycling than the other experimental groups and significantly decreased after 1,000 thermocycling (p < 0.05). 3. Panavia F 2.0 and Rely X Unicem showed the gradually decreased tendency of microtensile bond strength according to thermocycling but there was no significant difference (p > 0.05). 4. Adhesive based-resin cements showed lower bond strength with or without thermocycling than composite based-resin cements. 5. Variolink II & Multilink showed high bond strength and mixed failure, which was occurred with a thin layer of luting resin cement before thermocycling and gradually increased adhesive failure along the dentin surface after thermocycling. The bonding performance of resin cement can be affected by application procedure and chemical composition. Composite based-resin cement showed higher bond strength and durability than adhesive based-resin cement.