• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.132-135
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• 2005

The purpose of this study was to propose the modified strip crown technique for esthetic restoration of primary anterior teeth using glass fibers. Celluloid crown form(3M, USA), Z100(P shade, 3M, USA). Aeliteflo(Bisco Inc., USA), and Clearfil SE Bond(Kuraray Medical Inc., Japan) were used for this technique. Mesh type of glass fiber(TESCERA Fiber Mesh, Bisco Inc, USA) was used for reinforcing material. After trimming the celluloid crown form, resin adhesive and flowable resin were applied on the pre-shaped glass fiber mesh. That mesh was placed on the lingual surface of inside of celluloid crown form and followed by light activation. Composite resin was filled into the celluloid crown form and put it on a prepared tooth and then light activated and finished the margin. The new modified strip crown technique can provide esthetics and increased durability for restoration of primary anterior teeth.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.447-463
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• 1997

The purpose of this study was to evaluate the effectiveness of copal varnish and five bonding agents(Scotchbond Multi-Purpose Plus Dental Adhesive System, Panavia 21, All Bond 2, Superbond D-Liner II plus, Fuji Duet) in reducing microleakage under amalgam restorations. Class V cavity were prepared on both buccal and lingual surface of sixty extracted human molars with cementum margin and were filled with different kinds of liners and amalgam. All teeth were stored at $37^{\circ}C$ in physiologic saline solution. After 1 week they were thermally stressed for 500 cycles between 5 and $55^{\circ}C$ in baths containing 0.5 % basic fuchsin dye. The dye penetrations were observed with a stereomicroscope. Scanning electron micrographs were taken of representative tooth sections from each group to assess the nature of the tooth/liner/amalgam interface. The statistical test were applied to the results using a one way analysis variance (ANOVA) and Duncan's multiple range test. The results were as follows ; 1. In all groups, the enamel margin showed significantly lower leakage value than the cementum margin (p<0.05). 2. At the dentin and enamel margins, the leakage value of Copalite-lined group showed significantly higher than that of no liner group (p<0.05), but showed significantly lower than that of bonding agent lined-groups (p<0.05). 3. There was no significant difference between the bonding agent lined-groups (p>0.05). 4. On the backscattered scanning electron microscopy observation, discontinuous gaps were observed between amalgam and dentin in the bonding agent-lined amalgam restorations and the bonding agents appeared to fill the gap space and were mixed with amalgam particles. At the amalgam/tooth interface, unsealed dentin and continuous gaps were found in both unlined and Copalite-lined restorations.

• The Journal of Advanced Prosthodontics
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• v.8 no.1
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• pp.9-15
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• 2016

PURPOSE. Although magnetic attachment is used frequently for overdenture, it is reported that attractive force can be decreased by abrasion and corrosion. The purpose of this study was to establish the clinical basis about considerations and long term prognosis of overdenture using magnetic attachments by investigating the change in attractive force of magnetic attachment applied to the patients. MATERIALS AND METHODS. Among the patients treated with overdenture using magnetic attachments in Dankook University Dental Hospital, attractive force records of 61 magnetic attachments of 20 subjects who re-visited from July 2013 to June 2014 were analyzed. Dental magnet tester (Aichi Micro Intelligent Co., Aichi, Japan) was used for measurement. The magnetic attachments used in this study were Magfit IP-B Flat, Magfit DX400, Magfit DX600 and Magfit DX800 (Aichi Steel Co., Aichi, Japan) filled with Neodymium (NdFeB), a rare-earth magnet. RESULTS. Reduction ratio of attractive force had no significant correlation with conditional variables to which attachments were applied, and was higher when the maintenance period was longer (P<.05, r=.361). Reduction ratio of attractive force was significantly higher in the subject group in which attachments were used over 9 years than within 9 years (P<.05). Furthermore, 16.39% of total magnetic attachments showed detachment of keeper or assembly. CONCLUSION. Attractive force of magnetic attachment is maintained regardless of conditional variables and reduction ratio increased as the maintenance period became longer. Further study on adhesive material, attachment method and design improvement to prevent detachment of magnetic attachment is needed.

• The Journal of Advanced Prosthodontics
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• v.4 no.4
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• pp.187-191
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• 2012

PURPOSE. The aim of the present study was to assess the effect of ascorbic acid, ethanol and acetone on microtensile bond strength between fiber posts pre-treated with hydrogen peroxide and composite resin cores. MATERIALS AND METHODS. Twenty four fiber posts were pre-treated with 24% hydrogen peroxide and divided into 4 groups as follows: G1: no treatment, as control group; G2: treatment with10% ascorbic acid solution for 5 minutes; G3: treatment with 70% ethanol solution for 5 minutes; and G4: treatment with 70% acetone solution for 5 minutes. Each fiber post was surrounded by a cylinder-shaped polyglass matrix which was subsequently filled with composite resin. Two sections from each sample were selected for microtensile test at a crosshead with speed of 0.5 mm/min. Statistical analyses were performed using one-way ANOVA and a post hoc Tukey HSD test. Fractured surfaces were observed under a stereomicroscope at ${\times}20$ magnification. The fractured surfaces of the specimens were observed and evaluated under a SEM. RESULTS. Means of microtensile bond strength values (MPa) and standard deviations in the groups were as follows: G1: $9.70{\pm}0.81$; G2: $12.62{\pm}1.80$; G3: $16.60{\pm}1.93$; and G4: $21.24{\pm}1.95$. G4 and G1 had the highest and the lowest bond strength values, respectively. A greater bond strength value was seen in G3 compared to G2. There were significant differences between all the groups (P<.001). All the failures were of the adhesive mode. CONCLUSION. Application of antioxidant agents may increase microtensile bond strength between fiber posts treated with hydrogen peroxide and composite cores. Acetone increased bond strength more than ascorbic acid and ethanol.

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.114-123
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• 1994

The purpose of this study was to examine the shear bond strength of resin-enamel bond formed at specific time intervals after the termination ov vital bleaching. A total of 72 human extracted maxillary premolars were divided into nine groups : untreated control (group 1) ; enamel treated with 35% hydrogen peroxide(group 2, 3, 4, 5) ; and enamel reated with 15% carbamide peroxide gel (group 6, 7, 8, 9). After the treatment with 35% hydrogen peroxide for 2 hours and 15% carbamide peroxide for 24 hours, adhesion of a resin to bleached enamel was formed at 1 hour (group 2, 6) and 24 hours(group 3, 7) ; 3days(group 4, 8) and 7 days(group 5, 9) post-termination of bleaching treatment. A $3{\times}3mm$ mold was filled with Scotchbond Multi-Purpose and Z100. After 24 hours later, the specimens were shear-tested at crosshead speed 1mm/min and analyzed statistically. Fractured specimens from group 1,2, 6 were gold-coated with Eiko ion coater and observed under Scanning electron microscope at 25KV. The following results results were obtained : 1. Bonds formed at 1 hour post-termination of 35 % hydrogen peroxide(P<0.01) and 15 % carbamide peroxide bleaching treatment groups(P<0.05) showed significantly lower shear bond strength than untreated group. 2. Bonds formed at 24 hours, 3 days and 7 days post-termination of 35% hydrogen peroxide and 15 % carbamide peroxide bleaching treatment groups showed no significant differences in shear bond strength with untreated group(p>0.05). 3. SEM examinations of the untreated fracture specimen indicated cohesive fracture within enamel and exposed enamel prisms, but the bleached fracture specimens indicated adhesive fracture.

• Restorative Dentistry and Endodontics
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• v.39 no.4
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• pp.282-287
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• 2014

Objectives: The aim of the present study was to investigate the bond strength of RelyX Unicem (3M) to root canal dentin when used as an endodontic sealer. Materials and Methods: Samples of 24 single-rooted teeth were prepared with Gates Glidden drills and K3 files. After that, the roots were randomly assigned to three experimental groups (n = 8) according to the filling material, (1) AH Plus (Dentsply De Trey GmbH)/Gutta-Percha cone; (2) Epiphany SE (Pentron)/Resilon cone; (3) RelyX Unicem/Gutta-Percha cone. All roots were filled using a single cone technique associated to vertical condensation. After the filling procedures, each tooth was prepared for a push-out bond strenght test by cutting 1 mm-thick root slices. Loading was performed on a universal testing machine at a speed of 0.5 mm/min. One-way analysis of variance and Tukey test for multiple comparisons were used to compare the results among the experimental groups. Results: Epiphany SE/Resilon showed significantly lower push-out bond strength than both AH Plus/Gutta-Percha and RelyX Unicem/Gutta-Percha (p < 0.05). There was no significant difference in bond strength between AH Plus/Gutta-Percha and RelyX Unicem/Gutta-Percha (p > 0.05). Conclusions: Under the present in vitro conditions, bond strength to root dentin promoted by RelyX Unicem was similar to AH Plus. Epiphany SE/Resilon resulted in lower bond strength values when compared to both materials.

• Restorative Dentistry and Endodontics
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• v.44 no.3
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• pp.27.1-27.12
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• 2019

This case report describes a technique in which endodontic treatment and permanent indirect restoration were completed in the same clinical appointment with the aid of a computer-aided design/computer-aided manufacturing (CAD/CAM) system. Two patients were diagnosed with irreversible pulpitis of the mandibular first molar. After access preparation, root canals were located, irrigation was performed until bleeding ceased, and the coronal tooth structure was prepared for indirect restoration. Then, utilizing an interim 3-mm build-up of the endodontic access cavity, a hemi-arch digital scan was performed with an intraoral scanner. Subsequent to digital scanning, restoration design was performed simultaneously with the endodontic procedure. The root canals were shaped using the Race system under irrigation with 2.5% sodium hypochlorite followed by root canal filling. The pulp chamber was subsequently filled with a 3-mm-thick composite resin restoration mimicking the interim build-up previously utilized to facilitate block milling in the CAD/CAM system. Clinical try-in of the permanent onlay restoration was followed by acid etching, application of a 5th generation adhesive, and cementation of the indirect restoration. Once the restoration was cemented, rubber dam isolation was removed, followed by occlusal adjustment and polishing. After 2 years of follow-up, the restorations were esthetically and functionally satisfactory, without complications.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.2
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• pp.284-295
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• 1999

The purpose of this study was to measure and analyze the bond strength of bonded amalgam using dental adhesives and to compare this with light-curing composite resin. Sections 8mm in diameter were punched out from the labial surface of bovine anterior teeth. These were embedded in clear acrylic resin blocks with labial surface facing out. 55 specimens were made for enamel and dentin each. After dividing these into 5 groups, group 1: Superbond C&B, group 2: Panavia 21, group 3: All-Bond 2, group 4: Fuji I Glass Ionomer Luting Cement, group 5: Scotchbond Multi-Purpose(Restorative Z-100), molds with holes of 6.3mm in diameter and 1.5mm in depth were placed over the specimens. The exposed tooth surfaces were treated with adhesives and the molds were filled with amalgam. In group 5, the mold was filled with composite resin and light-cured for 40 seconds. The author measured all specimens for bond strength 24 hours after amalgam filing and analyzed fracture surfaces. The following results were obtained: 1. Among the dentin groups, groups 1, 2 and 4 showed significantly lower bond strength compared with group 5(P<0.05). 2. Among the enamel groups, group 4 showed significantly lower bond strength compared with group 5(P<0.05). 3. In group 2, 2D showed significantly lower bond strength compared with group 2E(P<0.05). Other adhesives showed no such differences in bond strength between dentin and enamel(P>0.05). 4. Cohesive failure was observed in groups 1E and 5D, while mixed failure was seen in groups 1 and 5. Only adhesive failures were noted in groups 2, 3, 4.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.164-172
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• 2010

During a composite resin restoration, an anticipating contraction gap is usually tried to seal with low-viscosity resin after successive polishing, etching, rinsing and drying steps, which as a whole is called rebonding procedure. However, the gap might already have been filled with water or debris before applying the sealing resin. We hypothesized that microleakage would decrease if the rebonding agent was applied before the polishing step, i.e., immediately after curing composite resin. On the buccal and lingual surfaces of 35 extracted human molar teeth, class V cavities were prepared with the occlusal margin in enamel and the gingival margin in dentin. They were restored with a hybrid composite resin Z250 (3M ESPE, USA) using an adhesive AdperTM Single Bond 2 (3M ESPE). As rebonding agents, BisCover LV (Bisco, USA), ScotchBond Multi-Purpose adhesive (3M ESPE) and an experimental adhesive were applied on the restoration margins before polishing step or after successive polishing and etching steps. The infiltration depth of 2% methylene blue into the margin was measured using an optical stereomicroscope. The correlation between viscosity of rebonding agents and mciroleakage was also evaluated. There were no statistically significant differences in the microleakage within the rebonding procedures, within the rebonding agents, and within the margins. However, when the restorations were not rebonded, the microleakage at gingival margin was significantly higher than those groups rebonded with 3 agents (p < 0.05). The difference was not observed at the occlusal margin. No significant correlation was found between viscosity of rebonding agents and microleakage, except very weak correlation in case of rebonding after polishing and etching at gingival margin.

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.46-55
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• 2000

During bonding procedure of composite resin, the prepared cavity can be contaminated by saliva. In this study, marginal microleakage and shear bond strength of a composite resin to primed enamel and dentin treated with artificial saliva(Taliva$^{(R)}$) were evaluated. For the marginal microleakage test, Class V cavities were prepared in the buccal surfaces of fifty molars. The samples were randomly assigned into 5 groups with 10 samples in each group. Control group was applied with a bonding system (Scotchbond$^{TM}$ Multi-Purpose plus) according to manufacture's directions without saliva contamination. Experimental groups were divided into 4 groups and contaminated with artificial saliva for 30 seconds after priming: Experimental 1 group ; artificial saliva was dried with compressed air only, Experimental 2 group ; artificial saliva was rinsed and dried. Experimental 3 group ; cavities were etched with 35% phosphoric acid for 15 seconds after rinsing and drying artificial saliva. Experimental 4 group ; cavities were etched with 35% phosphoric acid for 15 seconds and primer was reapplied after rinsing and drying artificial saliva. All the cavities were applied a bonding agent and filled with a composite resin (Z-100$^{TM}$). Specimens were immersed in 0.5% basic fuschin dye for 24 hours and embedded in transparent acrylic resin and sectioned buccolingually with diamond wheel saw. Four sections were obtained from one specimen. Degree of marginal leakage was scored under stereomicroscope and their scores were averaged from four sections. The data were analyzed by Kruscal-Wallis test and Fisher's LSD. For the shear bond strength test, the buccal or occlusal surfaces of one hundred molar teeth were ground to expose enamel(n=50) or dentin(n=50) using diamond wheel saw and its surface was smoothed with Lapping and Polishing Machine(South Bay Technology Co., U.S.A.). Samples were divided into 5 groups. Treatment of saliva-contaminated enamel and dentin surfaces was same as the marginal microleakage test and composite resin was bonded via a gelatin capsule. All specimens were stored in distilled water for 48 hours. The shear bond strengths were measured by universal testing machine (AGS-1000 4D, Shimaduzu Co., Japan) with a crosshead speed of 5 mm/minute. Failure mode of fracture sites was examined under stereomicroscope. The data were analyzed by ANOVA and Tukey's studentized range test. The results of this study were as follows : 1. Enamel marginal microleakage showed no significant difference among groups. 2. Dentinal marginal microleakages of control, experimental 2 and 4 groups were lower than those of experimental 1 and 3 groups (p<0.05). 3. The shear bond strength to enamel was the highest value in control group (20.03${\pm}$4.47MPa) and the lowest value in experimental 1 group (13.28${\pm}$6.52MPa). There were significant differences between experimental 1 group and other groups (p<0.05). 4. The shear bond strength to dentin was higher in control group (17.87${\pm}$4.02MPa) and experimental 4 group (16.38${\pm}$3.23MPa) than in other groups, its value was low in experimental 1 group (3.95${\pm}$2.51 MPa) and experimental 2 group (6.72${\pm}$2.26MPa)(p<0.05). 5. Failure mode of fractured site on the enamel showed mostly adhesive failures in experimental 1 and 3 groups. 6. Failure mode of fractured site on the dentin did not show adhesive failures in control group, but showed mostly adhesive failure in experimental groups. As a summary of above results, if the primed tooth surface was contaminated with artificial saliva, primer should be reapplied after re-etching it.