• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.3
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• pp.249-257
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• 2007

State of problem : The use of zirconium oxide all-ceramic material provides several advantages, including a high flexural strength(>1000MPa) and desirable optical properties, such as shading adaptation to the basic shades and a reduction in the layer thickness. Along with the strength of the materials, the cementation technique is also important to the clinical success of a restoration. Nevertheless, little information is available on the effect of different surface treatments on the bonding of zirconium high-crystalline ceramics and resin luting agents. Purpose : The aim of this study was to test the effects of surface treatments of zirconium on shear bond strengths between bovine teeth and a zirconia ceramic and evaluate differences among cements Material and methods : 54 sound bovine teeth extracted within a 1 months, were used. They were frozen in distilled water. These were rinsed by tap water to confirm that no granulation tissues have left. These were kept refrigerated at $4^{\circ}C$ until tested. Each tooth was placed horizontally at a plastic cylinder (diameter 20mm), and embedded in epoxy resin. Teeth were sectioned with diamond burs to expose dentin and grinded with #600 silicon carbide paper. To make sure there was no enamel left, each was observed under an optical microscope. 54 prefabricated zirconium oxide ceramic copings(Lava, 3M ESPE, USA) were assigned into 3 groups ; control, airborne-abraded with $110{\mu}m$ $Al_2O_3$ and scratched with diamond burs at 4 directions. They were cemented with a seating force of 10 ㎏ per tooth, using resin luting cement(Panavia $F^{(R)}$), resin cement(Superbond $C&B^{(R)}$), and resin modified GI cement(Rely X $Luting^{(R)}$). Those were thermocycled at $5^{\circ}C$ and $55^{\circ}C$ for 5000 cycles with a 30 second dwell time, and then shear bond strength was determined in a universal test machine(Model 4200, Instron Co., Canton, USA). The crosshead speed was 1 mm/min. The result was analyzed with one-way analysis of variance(ANOVA) and the Tukey test at a significance level of P<0.05. Results : Superbond $C&B^{(R)}$ at scratching with diamond burs showed the highest shear bond strength than others (p<.05). For Panavia $F^{(R)}$, groups of scratching and sandblasting showed significantly higher shear bond strength than control group(p<.05). For Rely X $Luting^{(R)}$, only between scratching & control group, significantly different shear bond strength was observed(p<.05). Conclusion : Within the limitation of this study, Superbond $C&B^{(R)}$ showed clinically acceptable shear bond between bovine teeth & zirconia ceramics regardless of surface treatments. For the surface treatment, scratching increased shear bond strength. Increase of shear bond strength by sandblasting with $110{\mu}m$ $Al_2O_3$ was not statistically different.

• Journal of Dental Rehabilitation and Applied Science
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• v.16 no.1
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• pp.51-60
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• 2000

The purpose of this study was to compare the microleakage at the interface of cast post and tooth according to the type of cement. Forty anterior teeth with single root were used. The teeth were cut 2 mm coronal from the cementoeamel junction and chamfer finish line was made on 1 mm coronal from the cementoeamel junction. After the routine endodontic treatment, post space was prepared using #5.5 Parapost drill to a depth of 7 mm. After the pick up impression, core building was made to 3 mm of clinical crown with burnout wax, then post and core was cast with nonprecious metal. The teeth were divided into four groups of ten each. In Group I, post and core were cemented with Fleck's(Zinc phosphate cement) In Group II, post and core were cemented with Fuji I(Glass ionomer cement) In Group III, post and core were cemented with Superbond C & B(Composite resin cement) In Group IV, post and core were cemented with Panavia 21(Composite resin cement) All cemented teeth were stored in normal saline at $37^{\circ}C$ for 7 days and thermocycled from $5^{\circ}C$ to $55^{\circ}C$ for 500 cycles with a dwell time of 30 seconds. After thermocycling, teeth were immersed in 1% Basic fuchsin dye for 48 hours. All 40 teeth were then embedded in the epoxy resin and cut buccolingually with a cutting instrument. The degree of penetration of dye at interface was graded on a scale of 0 to 4 using a stereomicroscope at 25 to 40 times magnification. Through the findings of this study, the following conclusion were obtained. 1. All the groups showed the microleakage at the interface of cast post core and tooth. 2. Group I showed the highest microleakage score among the groups with a significant difference(p<0.05). 3. Group II showed higher microleakage score than Group III and Group IV with a significant difference(p<0.05). 4. Group IV showed the lowest microleakage score but there were no significant difference with Group III(p>0.05).

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.112-124
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• 1997

According to extensive use of composite resin which have superior esthetic property, every effort on improving bonding strength between a tooth and composite resin has been continued. Acid etching technique is a method that micro-etches the tooth surface which provides bonding with composite resin possible. Recently, there were several reports that mechanical treatment obtained from air-abrasion can provide similar bonding strength with acid etching technique. So, this experimental study was designed to compare the shear bonding strength between using air-abrasion technique and using acid etching technique. Initially, bovine teeth were divided into enamel and dentin experimental groups. Respectively each group was categorized into three subgroups. One subgroup was acid etched with 35% phosphoric acid, then bonded with composite resin. The other subgroup was air-abraded with $50{\mu}m$ $Al_2O_3$ particles sprayed with 160psi air pressure using air abrasion unit(KCP-1000, A.D.T., U.SA), and composite resin was bonded. In another subgroup, composite resin was bonded after acid etching following air-abrasion. So, enamel experimental groups were made of E1 (acid etched only), E2(air-abraded only), E3(acid etched following air-abraded), and dentin experimental groups were made of D1(acid etched only), D2(air-abraded only), D3(acid etched following air-abraded). Each subgroup had 10 specimens. Dentin bonding system(Scotchbond Multi-purpose, 3M Co., U.S.A.) and composite resin(Z-100, 3M Co., U.S.A.) were applied on treated surface using 5mm diameter gelatin capsule as manufacturer's direction. After 1200 times thermocycling between $5^{\circ}C$ and $55^{\circ}C$, shear bond strength was measured in 5mm/min crosshead speed with Instron(Instron Co., U.S.A.), and also treated enamel and dentin were observed with SEM(JEOL Co., Japan). The following results were obtained: 1. In the enamel experimental groups, acid etched following air-abraded group had highest shear bond strength, but there was no significant difference compared to acid etched group. Air-abraded only group had lowest shear bond strength, and there was significant difference compared to the rest of groups. 2. In the dentin experimental groups, acid etched following air-abraded group had highest shear bond strength, but there was no significant difference compared to acid etched group. Air-abraded only group had lowest shear bond strength, and there was significant difference compared to the rest of groups. 3. In the SEM study, air-abraded enamel and dentin had irregular and rough surfaces.

• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.374-380
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• 2018

PURPOSE. The effect of silica-based glass-ceramic liners on the tensile bond strength between zirconia and resin-based luting agent was evaluated and compared with the effect of 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing primers. MATERIALS AND METHODS. Titanium abutments and zirconia crowns (n = 60) were fabricated, and the adhesive surfaces of the specimens were treated by airborne-particle abrasion. The specimens were divided into 5 groups based on surface treatment: a control group, 2 primer groups (MP: Monobond Plus; ZP: Z Prime Plus), and 2 liner groups (PL: P-containing Liner; PFL: P-free Liner). All specimens were cemented with self-adhesive resin-based luting agent. After 24-hour water storage and thermocycling (5,000 cycles, $5^{\circ}C/55^{\circ}C$), the tensile bond strength was measured using a universal testing machine. Failure mode analysis and elemental analysis on the bonding interface were performed. The data were analyzed using Kruskal-Wallis test, Dunn's post hoc test, and Fisher's exact test. RESULTS. The liner groups and primer groups showed significantly higher tensile bond strengths than that of the control group (P<.05). PFL showed a significantly higher tensile bond strength than the primer groups (P<.05). The percentage of mixed failure was higher in the primer groups than in the control group (P<.001), and all the specimens showed mixed failure in the liner groups (P<.001). A chemical reaction area was observed at the bonding interface between zirconia and liner. CONCLUSION. The application of liner significantly increased the tensile bond strength between zirconia and resin-based luting agent. PFL was more effective than MDP-containing primers in improving the tensile bond strength with the resin-based luting agent.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.200-206
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• 2014

PURPOSE. This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane-or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS. Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate-and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (${\alpha}$=0.05). RESULTS. Mean fracture resistance for the eight groups (in Newton) were G1: $1200{\pm}169^a$, G2: $360{\pm}93^b$, G3: $632{\pm}196^c$, G4: $692{\pm}195^c$, G5: $917{\pm}159^d$, G6: $1013{\pm}125^{ad}$, G7: $959{\pm}148^d$, G8: $947{\pm}105^d$ (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION. Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.2
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• pp.293-299
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• 2005

It is important to reduce chair time and procedure in restorative treatment for children. Composite resin is not only used in esthetic restoration of anterior teeth but also posterior teeth by its improved physical property. The 7th generation dentin bonding system was recently developed in order to simplify three steps which is needed to bond composite resin to tooth surface-etchant, primer, adhesive. We compared shear bond strengths of 4, 5, 6, 7th generations dentin bonding systems. The primary dentin was pretreated with 4, 5, 6, 7th generation dentin bonding systems. Then composite resin was cured to the specimen using molds 2.5mm in diameter and 2mm in height. Thermocycling was performed and shear bond strength was finally measured. The results were as follow; 1. The mean values of shear bond strengths in 5th generation dentin bonding system(group 2) were greater than those of 4, 6, 7th generation dentin bonding system(group 1, 3, 4). The differences were statistically significant. 2. The mean values of shear bond strengths in 4th generation dentin bonding system(group 2) were greater than those of 6, 7th generation dentin bonding system(group 1, 3, 4). But, the differences were not statistically significant. 3. Between the mean values of shear bond strengths in 6, 7th generation dentin bonding system(group 3, 4) were similar.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.3
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• pp.157-170
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• 2002

The purpose of this study is to analyze the shear bond strength according to kinds of surface treatment agents and resin cements after acid etching of IPS Empress 2. For this purpose, test groups were classified into silane-treated bonding groups, silica-coated group and Targis link applied group. Then, nine bonding groups in total, each three groups per kind, were prepared by using three kinds of resin cements-Panavia F, Variolink II and Rely-X ARC, and thirty test specimens per group were prepared. To examine any changes in the oral environment, the shear bond strength of each test specimen was measured after dipping test for 24 hours and for five weeks, respectively, in distilled water at $37^{\circ}C$ and performing heat cycle 10,000 times in total, each 2,000 times per week, during a five weeks of dipping, under the condition similar to the oral environment. The bond failure modes were also observed by means of a scanning electron microscope. The results are summarized as follows 1. Statically significant differences between the surface conditioning materials were observed. The shear strength of the silane treatment was the highest of all three types of surface treatments(p<0.001). 2. Shear strengths varied significantly for different types of resin luting agents. But bond strength of Targis link surface treatments were not significantly different(p<0.05). 3. No significant difference of bonding strengths was found between storage time conditions(24 hours and 5 weeks). Only group II, IV, VII, IX were significantly different(p<0.05). 4. After thermocycling, the shear bond strengths of all groups were significantly decreased (p<0.05). Group III, V, VI were no significantly different. 5. On the SEM observation of fractured surfaces, all groups were shown complex failure.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.164-173
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• 2005

Mechanical preparation has been introduced to provide the sealant retention. The objective of this study was to compare the fissure penetration and the microleakage of pit and fissure sealant using mechanical preparation(mechanical preparation + acid etching) and acid etching only. An additional objective of this study was to compare the fissure penetration and the microleakage of unfilled and filled sealant in both methods. Sixty human premolars extracted for orthodontic purpose were selected. Thirty teeth were acid etched alone and remaining thirty teeth were prepared with a $\frac{1}{4}$ round bur and then acid etched. One-half of teeth in each surface treatment method were sealed with unfilled sealant and the other half were sealed with filled sealant. All of the teeth were thermocycled for 1200 cycles at $5^{\circ}C\;and\;55^{\circ}C$ and immersed in 5% methylene blue for 24 hours. Each tooth was sectioned bucco-lingually at mesial pit and distal pit and examined under a Measurescope. In the case of mechanical preparation, fissure penetration of sealant was significantly increased compared with the case of acid etching only(P < 0.05). The filled and unfilled sealant using mechanical preparation showed significantly decreased microleakage when compared with the unfilled sealant using acid etching only(P < 0.05). No differences were found in fissure penetration and microleakage between unfilled and filled sealant in both methods. Taken together, the results of this study suggest that mechanical preparation and filled sealant are recommended when placing pit and fissure sealant. However, further clinical studies should be performed in regard to microleakage.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.504-511
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• 2001

Preventive resin restoration, extended concept of occlusal pit and fissure sealing, is procedure composed of as follows. Cavity preparation is limited to areas of initial caries The cavity is then restored with composite resin, while other sound pits and fissures are sealed with pit and fissure sealant. If pit and assure sealant with which microrestoration is possible is used, it may be of great benefit to both patient and operator in case of difficult-to-control children s treatment. However study on preventive resin restoration using this kind of materials have been scarce. The purpose of this study was to compare the microleakage of four different modes of preventive resin restoration. Restoration using only composite resin was compared together Fifty-five bicuspids were prepared with small class I cavity preparation on the occlusal surface, divided into the following groups and restored accordingly. Group 1 : Cavity was restored with Z-100 composite resin Group 2 : Cavity was restored with Z-100 composite resin. Pits and fissures were then sealed with Teethmate F-1 Group 3 : Cavity was restored with Z-100 composite resin Pits and fissures were then sealed with Ultraseal XT-plus Group 4 : Cavity and pits and fissures were restored with Ultraseal XT-plus altogrether Group 5 : Cavity was restored with Ultraseal XT-plus. Pits and fissures were then sealed with the same material. After restoration, the samples were thermocycled 500 times between $5^{\circ}C$ and $55^{\circ}C$ with a dwell time of 30 seconds. After thermocycling, the samples were dipped into 1% methylene blue solution for 24 hours, then rinsed with tap water. The teeth were then embedded in resin and cut buccolingually along the tooth axis and observed with a stereomicroscope to determine the degree of microleakage. The results were as follows : 1. Group 4 showed the greatest microleakage, while group 3, showed the least. The mean microleakage decreased in the following order:4>1>5>2>3. 2. There was no stastically significant difference between group 1 and group 5(p>0.05). However, group 1 showed significantly greater microleakage compared to group 2 and 3(p<0.05) Group 1 showed significantly less microleakage compared to group 4(p<0.05). 3. Group 2 showed no statistically significant difference compared to group 3(p>0.05). However group 2 showed significantly less microleakage compared to group 4 and 5(p<0.05) 4. Group 3 showed significantly less microleakage compared to group 4 and 5(p<0.05). 5. Group 5 showed significantly less microleakage than group 4(p<0.05).