• Restorative Dentistry and Endodontics
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• v.28 no.3
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• pp.222-231
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• 2003

The purpose of this study was to compare shear bond strength and interfacial pattern of composite bond-ed to dentin using self-etching adhesive systems. Sixty extracted human molars with exposed occlusal dentin were divided into four groups and bonded with four adhesives and composites. Single Bond/Filtek Z 350(SB), Tyrian SPE-One-Step Plus/Aelitefil(TY), Prompt L-Pop/Filtek Z 250(LP), and One-Up Bond F/palfique Toughwell(OU). The results of this study were as follows; 1 Shear bond strength for OU was significantly lower than that of other groups(p＜0.05). No significant difference was founded among SB, TY, and LP. 2. Failure modes to dentin showed adhesive and mixed for SB TY and LP, but them for OU showed adhesive in all spceimens. 3. Dentin-resin interface showed close adaptation for SB, TY, and LP, but it showed gap for OU. 4. The hybrid layers for TY, LP OU were thinner than that of SB. Adhesive layers were observed between composite and hybrid layer, which were 5 $\mu\textrm{m}$ thick for TY and 10 $\mu\textrm{m}$ thick for OU.

• Restorative Dentistry and Endodontics
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• v.24 no.2
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• pp.381-391
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• 1999

A new 5th generation adhesive system(ONE-STEP) has been supplied which operators can apply to conditioned tooth surfaces by one simplified step. The purpose of this study was to determine whether different methods of adhesive application and various air drying duration after applying adhesive affect the shear bond strength of composite resin to dentin, and to evaluate the adhesive pattern of composite resin and dentin under SEM. Seventy-seven extracted human molar teeth were cleaned and mounted in palstic test tubes. The occlusal dentin surfaces were exposed with Diamond Wheel Saw and smoothed with Lapping and Polishing Machine (South Bay Technology Co., U.S.A.). Teeth were randomly divided into 7 groups (n=11), In experimental A group, adhesive was applied to dentin with agitation for 20 sec. In experimental N-A group, adhesive were continuously applied to dentin for 20 sec. Also control and experimental 1, 2, 3, 4 groups were dried for 10, 0, 5, 20, 30 seconds after applying adhesive, respectively, Adhesives were light cured for 10 sec. A gelatin capsule 5mm in diameter was filled with Aelitefil$^{TM}$ composite resin, placed on the treated dentin surface and light cured for 40 see, from three sides, All specimens were stored in distilled water at room temperature for 24 hours. The shear bond strengths were measured using a universal testing machine(AGS-1000 4D, Japan) at a crosshead speed of 5mm/min. An one-way ANOVA and LSD test were used for statistical analysis of the data. For SEM evaluation, seven specimens were made and sectioned. Representive postfracture and seven specimens were mounted on brass stubs, sputter-coated with gold and observed under SEM. The results were as follows : 1. The shear bond strength of experimental A group which adhesive were applied to dentin with agitation was higher than that of experimental N-A group (continuous application), and there was significant difference between two groups (p<0.01). 2. The interface between composite and dentin according to different application methods showed close adaptation in experimental A group and showed tinny gap in experimental N-A group. 3. The shear bond strength accoding to various air drying duration was the lowest value(7.57${\pm}$2.60 MPa) in experimental 1 group, so there was significant difference between experimental 1 group and other four groups (p<0.05). But there was no significant difference of shear bond strength between four groups (p>0.05). 4. The interface between composite and dentin according to various air drying duration showed close adaptation in control group and tinny gap in experimental 3 and 4 groups. But experimental 1 and 2 groups showed $30{\mu}$ and 6 - $10{\mu}m$ thick gaps, respectively.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.359-369
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• 2007

This in vitro study was performed to assess the effect of surface sealing on the microleakage of class V composite resin restorations that underwent several aging treatments. Class V cavities were prepared on the buccal surface of 100 sound extracted premolars and restored with a hybrid light-cured composite resin according to the manufacturer's instructions. They were randomly divided into two groups consisting of 50 samples: group I, without surface sealing, and group II, in which margins were etched and surface sealant was applied. After thermocycling, each group was divided into five subgroups, respectively, to represent the five aging treatments: group A = no further treatment (only thermocycling), B = toothbrushing, C = load cycling, D = toothbrushing followed by load cycling, and E = aging treatment in deionized water for six months. Microleakage was assessed by examining the penetration of 2% methylene blue dye. The following results were obtained: 1. At occlusal and cervical margins in groups without surface sealing, there was no significant difference in microleakage after the several aging treatments (p>0.05). 2. The occlusal margins of groups with surface sealing showed no significant differences after the several aging treatments (p>0.05). 3. In the cervical margins of groups with surface sealing, microleakage significantly increased after load cycling or aging in deionized water for six months (p<0.05). 4. The no-further-treatment group and the toothbrushing group with surface sealing showed less microleakage than the corresponding groups without surface sealing (p<0.05). 5. The surface-sealed groups with load cycling or aging in deionized water showed no significant difference in microleakage to the corresponding groups without surface sealing (p>0.05). In conclusion, the results of this study suggest that the surface sealant infiltrating through the gap of the cervical margin exerted a positive effect on microleakage at the initial stage, but the effect was not sufficient to overcome the stress generated by the cuspal flexure during occlusal loading and water absorption.

• 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.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.5
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• pp.571-577
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• 2008

Introduction: Possible etiologic factors associated with bone loss around implants after implantation are surgical trauma, occlusal overload, periimplantitis, presence of micro gap and the formation of biologic distances. Tarnow et al. observed that the crestal bone loss was greater when the distance between the implants was <3mm than when the implants were ${\geq}\;3mm$ apart. The aim of this study was to evaluate the influence of different interimplant distance on marginal bone and crestal bone resorption in the beagle dogs. Materials and methods: The mandibular premolars of 5 dogs were extracted bilaterally. After 12 weeks of healing, each dog received 7 implants. On each side, implants were separated by 2mm (Group 1) and by 5mm (Group 2). After 16 weeks of healing, the dogs were sacrificed. Marginal bone loss was determined through linear measurements made between the implant-abutment junctions and the most coronal portions of the bone in contact with the implant surface. A line was drawn uniting the implant-abutment junctions of the adjacent implants, and a linear measurement was made at the midpoint in the direction of the most coronal peak of the interimplant bone crest to determine the crestal bone loss. Both of them was measured radiologically and histologically. Result and conclusion: In radiological analysis, the mean of marginal bone loss was $1.26{\pm}0.14mm$ for group 1 and $1.23{\pm}0.34mm$ for group 2, the mean of crestal bone loss was $1.10{\pm}0.14mm$ for group 1 and $1.02{\pm}0.30mm$ for group 2. The results were not statistically significant between 2 groups. In histological analysis, the mean of marginal bone loss was $1.63{\pm}0.48mm$ for group 1 and $1.62{\pm}0.50mm$ for group 2, the mean of crestal bone loss was $1.23{\pm}0.35mm$ for group 1 and $1.15{\pm}0.39mm$ for group 2. The differences were also not statistically significant. The clinical significance of this result is that the increase in the crestal bone loss results in the increase in the distance between the base of the interproximal contact of the crowns and the bone crest, and this determines if papilla will be present or absent between implants. Considering this fact, keeping up sufficient interimplant distance is important to minimize crestal bone loss.

• Restorative Dentistry and Endodontics
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• v.28 no.1
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• pp.11-22
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• 2003

This study compared the dentin adhesion to composite resin according to air-dry, blot dry, application of rewetting agent on air-dry or blot dry dentin surface by microleakag test and SEM observation. For microleakage test, class V cavity preparations with dentinal margins were prepared on both buccal and lingual surfaces of 40 extracted human molars. For SEM observation, occlusal dentin of 20 extracted human molars were exposed. After etched the dentin, prepared teeth were randomly divided into four groups; D group: air dry for 10-15 sec., B group: blot dry with moist cotton pellet, D-R group: air dry and rewet with Aqua-Prep F for 20 sec., B-R group: blot dry and rewet with Aqua-Prep F for 20 sec. Treated cavities and surfaces were filled or constructed using One-Step adhesives and Aelitefil composite resins. Specimens were stored in distilled water for 24 hours. For microleakage test, the specimens were thermocycled and soaked into 2% methylene blue. The specimens were sectioned longitudinally and evaluated for microleakage under steromicroscope. The data were statistically analysed by Kuskal-Wallis Test, Mann-Whitney and Wilcoxon signed ranked tests. For SEM observation, the specimens were bisectioned mesiodiatally. After decalcified and deproteinized, specimens were observed under SEM. The results of this study were as follows; 1. The microleakges on dentinal margin were the highest in D group compared with B group, D-R group, and B-R group(p<0.05). But there was no significant difference between B group, D-R group and B-R group. 2. D group showed gap and a few resin tags between dentin and composite resin. 3 B group, D-R group, and B-R groups showed close adaptation between dentin and composite resin. It showed that resin rags in B group were numerous and long, in D-R group were few and short, in B-R group were numerous and short or long. 4. Adhesive layer showed in D-R group ($10{\;}\mu\textrm{m}$) and B-R group ($3{\;}\mu\textrm{m}$) In conclusion, use of rewetting agent to dry dentin was efficient to dentin adhesion, also it did not provide reverse effect on blot dry dentin.

• Restorative Dentistry and Endodontics
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• v.30 no.3
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• pp.204-214
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• 2005

This study compared the microtensile bond strength (${\mu}$TBS) and microscopic change of two 2-step and two 1-step self-etching adhesives to dentin according to storage times in distilled water. Occlusal dentin was exposed in 48 human molars. They were divided to four groups by different adhesives: SE Bond group (Clearfil SE Bond), AdheSE group (AdheSE). Adper group (Adper Prompt L-Pop), and Xeno group (Xeno III) . Each group was stored in 37$^{\circ}C$ distilled water for 1, 15, and 30 days. Resin-bonded specimens were sectioned into beams and subjected to ${\mu}$TBS testing with a crosshead speed of 1 mm/minute. For SEM observation, one specimen was selected and sectioned in each group after each stroage time. Resin-dentin interface was observed under FE-SEM. In all storage times, mean ${\mu}$TBS of SE group was significantly higher than those of other groups (p < 0.05). There was no significant difference between mean ${\mu}$TBS of SE group and AdheSE group among all storage times, but significant difference between 1- and 30-day storage in mean y${\mu}$TBS of Adper group and Xeno group (p > 0.05). For 1-and 15-day storage, all groups showed the close adaptation between resin-dentin interfaces. For 30-day storage, resin-dentin interfaces showed wide gap in Adper group and separate pattern in Xeno III group.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.654-660
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• 2001

Dentinogenesis imperfecta is an example of an inheritable dentinal defect originating during the histodifferentiation stage of tooth development, with involvement of the primary and permanent teeth. Shields, Bixler and El-Kafrawy proposed three types of Dentinogenesis imperfecta : Type I, II, III. Witkop reported a prevalence of 1 in 8000 with the trait, and no significant difference between male and female. Affected teeth have red-brown discoloration often with distinctive wearness of occlusal surface of posterior teeth and incisal surface of anterior teeth. Once enamel seperated from underlying defective dentin, the dentin demonstrates significantly acclerated attrision. Radiographically, the teeth have thin roots, bulbous crown, cervical constriction, and obliteration of the root canals and pulp chambers. In primary dentition periapical lesions or multiple root fractures are often observed. In successive generations the phenotypes of discoloration and wearness of teeth occurred, and one of the patient's subships, 10 year-old sister, showed general discoloration of her teeth and mild wearness. In this case, a 4 year-old male reported to the Yonsei University Pedodontics clinic, with a chief complaint of discolored teeth. The teeth showed generally yellowish-brown discoloration and moderate wearness. In radiographic features, obliteration of pulp, bulbous crown, and short roots were observed. It was diagnosed as Dentinogenesis imperfecta. The posterior teeth were restored with Stainless Steel Crown, and defective incisors including left upper primary central incisor which was extracted due to a root fracture with Open-faced Stainless Steel crown.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.2
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• pp.143-150
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• 2010

Purpose: The purpose of this study is to fabricate the new zirconia block (CNU block) and to evaluate fit of core and porcelain veneered zirconia crown. Material and methods: The experimental blocks were fabricated from the commercial ytrria-stabilized zirconia powder (KZ-3YE Type A). The powder was uniaxial pressing and the green bodies were conducted using the Cold Isostatic Pressing. The zirconia blocks were presintered at $1040^{\circ}C$ and the final sintering was performed at $1450^{\circ}C$. The Kavo Everest ZS $blank{(R)}$ (KaVo, Biberach/ $Ri{\beta}$.) was used as a control group. The linear shrinkage of CNU block and Kavo block were compared. Twenty-one cores for porcelain veneered crowns were fabricated with CAD/CAM system ($Everest{(R)}$, Biberach/ $Ri{\beta}$.). Group I; seven cores fabricated from Kavo blocks, Group II; seven cores fabricated from CNU blocks, Group III; seven cores from CNU blocks and porcelain veneering for crowns. All specimens were cemented and sectioned into two planes; diagonal and bucco-lingual. The measurement of the marginal, internal, and occlusal fit was carried out using SEM ($S-4800^{(R)}$) at $30{\times}$. The results were analyzed by one-way ANOVA test. Results: The linear shrinkage of the CNU block and the KaVo block was 19.00% and 20.09%. The marginal gap of cores ($29.67{\pm}6.58{\mu}m$) fabricated from CNU blocks showed significantly smaller than that of the cores of Kavo blocks ($36.84{\pm}7.18{\mu}m$) (P < .05). The internal gaps of the porcelain veneered crowns ($32.23{\pm}6.33{\mu}m$) were larger than those of the other two groups ($37.57{\pm}6.81{\mu}m$ and $38.14{\pm}6.81{\mu}m$). Conclusion: No statistically significant difference was found in between experimental groups and control group. The experimental groups in marginal gap showed significantly smaller than the control group.

• Restorative Dentistry and Endodontics
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• v.29 no.2
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• pp.170-176
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• 2004

Objectives : In the unique metal iris method. the developing interfacial gap at the cavity floor resulting from the cavity wall property during polymerizing composite resin might affect the nominal shear bond strength values. The aim of this study is to evaluate that the iris method reduces the cohesive failure in the substrates and the cavity wall property effects on the shear bond strength tests using iris method. Materials and Methods : The occlusal dentin of 64 extracted human molars were randomly divided into 4 groups to simulate two different levels of cavity wall property (metal and dentin iris) and two different materials ($ONE-STEP^{\circledR}$ and $ALL-BOND^{\circledR}$ 2) for each wall property. After positioning the iris on the dentin surface. composite resin was packed and light-cured. After 24 hours the shear bond strength was measured at a crosshead speed of 0.5 mm/min. Fracture analysis was performed using a microscope and SEM. The data was analyzed statistically by a two-way ANOV A and t-test. Results : The shear bond strength with metal iris was significant higher than those with dentin iris (p＝0.034). Using $ONE-STEP^{\circledR}$, the shear bond strength with metal iris was significant higher than those with dentin iris (p＝0.005), but not in $ALL-BOND^{\circledR}$ 2 (p＝0.774). The incidence of cohesive failure was very lower than other shear bond strength tests that did not use iris method. Conclusions：The iris method may significantly reduce the cohesive failures in the substrates. According to the bonding agent systems. the shear bond strength was affected by the cavity wall property.