• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.399-407
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• 1998

In order to resolve enamel demineralization around orthodontic bracket, fluoride-releasing materials, glass ionomer cements and fluoride-containing resin, were introduced in orthodontic department. There were many studies about their fluoride release, but their results were controversial. The purpose of this study was to clarify the pattern and amounts of fluoride release from glass ionomer cements and a fluoride-containing resin during 70 days in vitro. Disc shaped specimens were prepared and immersed in polyethylene tube containing 2ml distilled deionized water. The daily amounts of the fluoride released from each specimens were measured after experiment 1 day, 3 days, 7 days, 14 days, 42 days and 70 days. They were measured by fluoride-specific electrode combined pH/Ion meter. The following results were as follow, 1. Fluorides released from fluoride-containing resin during 1 day were significantly less than those from glass ionomer cements. 2. On experiment 70 days, mean daily amounts of fluoride released from Miracle-$Mix^{\circledR}$were $3.4{\mu}g/cm^2$, those from Fuji GC $II^{\circledR}$ were $2.7{\mu}g/cm^2$, those from $Orthobond^{\circledR}$ were $2.3{\mu}g/cm^2$, those from Fuji GC $LC^{\circledR}$were $1.4{\mu}g/cm^2$ and those from fluoride-containing resin, $Heliomolar^{\circledR}$, were $0.1{\mu}g/cm^2$. 3. There were no significant differences in daily amounts of fluoride released from between self-curing glass ionomer cements and light-curing glass ionomer cements. Amounts of released fluoride varied among commercially available products. 4. In all experimental materials, amounts of released fluoride decreased rapidly until experimental 3 days and then decreased slowly until 14 days and more slowly until 70 days.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.2
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• pp.112-118
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• 2012

Purpose: The purpose of this study was to evaluate the difference in shear bonding strength between resin cements to dental materials when a universal primer (Monobond plus) was applied in place of a conventional primer. Materials and methods: Four groups of testing materials: gold alloy (Argedent Euro, n = 16), non precious metal (T-4, n = 20), zirconia (Cercon, n = 20) and glass ceramic (IPS e.max press, n = 20), were fabricated into discs, which were embedded in an acrylic resin matrix. The gold alloy specimens were airborne-particle abraded, 8 of the specimens were coated with Metal primer II, while the remaining 8 specimens were coated with Monobond plus. The non precious and zirconia specimen were airborne-particle abraded then, the control group received Alloy primer coating, while the other was coated with Monobond plus. Glass ceramic specimens were etched. 10 specimens were coated with Monobond-S and the remaining specimens were coated using Monobond plus. On top of the surface, Multilink N was polymerized in a disc shape. All of the specimens were thermal cycled before the shear bonding strength was measured. Statistical analysis was done with Two sample $t$-test or Mann-Whitney U test (${\alpha}$=.05). Results: There were no significant differences in bonding strength depending on the type of primer used in the gold alloy and glass ceramic groups ($P$>.05), however, the bonding strengths of resin cements to non precious metal and zirconia groups, were significantly higher when the alloy primer was used ($P$<.05). Conclusion: Within the limitations of this study, improvement of universal primers which can be applied to all types of restorations is recommended to precious metals and zirconia ceramics. But, the bond strengths of non precious metals and zirconia ceramics were significantly lower when compared to a 10-MDP primer. More research is needed to apply universal primers to all types of restorations.

• The korean journal of orthodontics
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• v.32 no.4 s.93
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• pp.293-300
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• 2002

The purpose of this study was to evaluate the clinical effectiveness of hydrophilic primer, which claim to retain adequate bond strength on moistened enamel resulting from moisture or saliva contamination, by comparing the shear bond strength and adhesive failure patterns of brackets bonded using hydrophilic primer and conventional hydrophobic primer. Brackets were bonded to human premolars embedded in metal cylinders utilizing light cured adhesive, primed with either a hydrophilic primer(Transbond fm primer) or a conventional hydrophobic primer(Transbond XT primer). Each sample was exposed to varying degrees of artificial saliva contamination during the priming process. The shear bond strength was measured using a universal testing machine, and the adhesive failure patterns after debonding were visually examined by strereomicroscope and assessed using the adhesive remnant index(ARI). The results were as follows 1. In dry conditions, no significant differences in shear bond strength between Transbond W and Transbond XT primers were found. 2. Transbond MIP primer exhibited a significantly higher shear bond strength than Transbond XT primer in saliva-contaminated conditions, regardless of the degree of contamination. 3. When contaminated with one coat of saliva, Transbond MIP primer did not exhibit significant differences in shear bond strength compared to the dry condition. When contaminated with two coats of saliva, Transbond MIP primer exhibited a singnificantly lower shear bond strength compared to the dry condition. 4. The adhesive remnant index of the adhesive failure pattern had a tendency to decrease, as the degree of saliva contamination increased. Bracket-adhesive interface failure was observed in more than half of the saliva contaminated samples utilizing Transbond MIP primer, whereas the bond failure sites of the Transbond XT primer samples occurred almost exclusively at the adhesive-enamel interface in saliva-contaminated conditions. The results of this study suggest that in cases where moisture control is difficult, Transbond MIP primer is an effective alternative to conventional hydrophobic primers.

• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.19-27
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• 2007

The purpose of this study is to develope new dental color-space system. Twelve kinds of dental composites and one kind of dental porcelain were used in this study. Disk samples (15 mm in diameter, 4 mm in thickness) of used materials were made and sample's CIE $L^*a^*b^*$ value was measured by Spectrocolorimeter (MiniScan XE plus, Model 4000S, diffuse/$8^{\circ}$ viewing mode, 14.3 mm Port diameters, Hunter Lab USA) The range of measured color distribution was analyzed. All the data were applied in the form of T### which is expression unit in CNU Cons Dental Color Chart. The value of $L^*$ lies between 80.40 and 52.70. The value of $a^*$ are between 10.60 and 3.60 and $b^*$ are between 28.40 and 2.21. The average value of $L^*$ is 67.40, and median value is 67.30. The value of $a^*$ are 2.89 and 2.91 respectively. And for the $b^*$, 14.30 and 13.90 were obtained. The data were converted to T### that is the unit count system in CNU-Cons Dental Color Chart. The value of $L^*$ is converted in the first digit of the numbering system. Each unit is 2.0 measured values. The second digit is the value of $a^*$ and is converted new number by 1.0 measured value. For the third digit $b^*$ is replaced and it is 2.0 measured unit apart. T555 was set to the value of $L^*$ ranging from 66.0 to 68.0, value of $a^*$ ranging from 3 to 4 and $b^*$ value ranging from 14 to 16.

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.2
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• pp.73-81
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• 2013

Purpose: The purpose of this study was to evaluate the effect of surface treatment on the shear bond strength of zirconia ceramic to 3 resin cements. Materials and methods: A total of 143 disk-shaped Zirconia blocks (HASS Co., Gangneung, Korea) were randomly divided into three treatment groups: (1) only 50 ${\mu}m$ $Al_2O_3$ sandblasting, (2) 50 ${\mu}m$ $Al_2O_3$ sandblast and zircona liner, (3) 50 ${\mu}m$ $Al_2O_3$ sandblasting and Rocatec (3M ESPE, Seefeld, Germany). Bistite II (Tokuyama Dental Co., Japan), Panavia F (Kuraray Medical, Japan), and Superbond C&B (Sun Medical, Japan) were used to cement onto the zirconia. After 24h of storage in distilled water, shear bond strength was evaluated. High value group was re-tested after thermocycling at 5,000 cycles(5-$55^{\circ}C$). Shear bond strength data were analyzed with one-way ANOVA, two-way ANOVA test and Post Hoc Test (${\alpha}$=.05). Shear bond strength data before and after thermocycling were analyzed with Independent sample T test (${\alpha}$=.05). Results: Super-bond C&B treated with Rocatec showed the most high shear bond strength. Super-bond C&B groups resulted in significantly higher than other cement groups (P<.05). Rocatec groups resulted in significantly higher than other surface treatment groups (P<.05). Shear bond strength has increased in Panavia F treated with Zirconia liner (P<.05). After thermocycling, shear bond strength was increased in Super-bond C&B treated with Rocatec but decreased in other groups (P<.05). Conclusion: Super-bond C&B cement resulted the highest shear bond strength and Rocatec system enhanced the shear bond strength. After thermocycling, shear bond strength has decreased in most resin cements except Super-bond C&B treated with Rocatec.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.403-411
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• 2001

The aim of this study was to evaluate the resistance to degradation of four commercial composite resins in an alkaline solution. The brands studied were Unifil(GC, Japan), Palfique(Tokuyama Japan). Definite$Degussa-H\ddot{u}ls$ AG, Germany). Revolution(Kerr, U.S.A.). Preweighed discs of each brand were exposed 0.1N NaOH solution at $60^{\circ}C$. After 14 days they were removed, neutralized with HCl, washed with water and dried. Resistance to degradation was evaluated on the basis of following parameters: (a) mass loss(%) - determined from pre-and post-exposed specimen weights; (b) Si loss(ppm) - obtained from ICP-AE analysis of solution exposed to specimens; and (c) degradation depth$({\mu}m)$ - measured microscopically (SEM) from polished circular sections of exposed specimens. The results were follows: 1. The mass loss of Unifil was 3.21%, it was the highest of materials. But, there was no significant difference among the materials. 2. The degree of degradation layer depth was $107.69\sim47.40{\mu}m$, the sequence of the degree pf degradation layer depth was in descending order by Unifil, Palfique, Revolution, Definite. There was significant difference among the materials except Palfique and Definite. 3. The Si loss of Paltique was 8940.0ppm, it was the highest. There was significant difference among the materials, except Revolution and Definite(p<0.05). 4. The correlation coefficient between mass loss and degradation depth was relatively high(r = 0.06, p<0.05). 5. There was no significant coefficient correlation between Si loss and mass loss, and/or the degree of degradation layer depth and Si loss. 6. When observed with SEM, destruction of bonding is observed between resin matrix and filler. Above results suggested that the hydrolytic degradation is considered as evaluation factor of composite resins.

• Journal of Dental Rehabilitation and Applied Science
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• v.40 no.2
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• pp.64-71
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• 2024

Purpose: The purpose of this study is to evaluate Ti-base abutment's three different heights and three different cement types on the pull-off force of zirconia-based restorations. Materials and Methods: A total of 90 fixture lab analogs were embedded in auto polymerizing resin bloack. 90 Ti-base abutments heights of 3 mm, 5 mm, 7 mm were scanned and zirconia restoration were prepared from scanned files. Zirconia restoration were cemented with three different types of cements (temporary, semi-permanent, permanent) following manufacturer's instructions. All 90 specimens were placed and tested in a universal testing machine for pull-out testing. Retention was measured by recording the force at load drop. Statistical analysis was performed using Kruskal-Wallis test for detecting whether there are any statistical significance along cement types or abutment heights. After that, Mann-Whitney test was used for figuring out differences regarding abutment height and the comparison between 3 cements. Results: Temp bond showed significantly lower pull-off force compared to Fujicem regardless of any abutment height. However, there were significant differences between Cem-implant and Fujicem in abutment height of 3 mm and 7 mm, but there was no significant difference in 5 mm. Temp bond and Cem-implant had significant differences only in abutment height of 5 mm. Conclusion: Although Ti-base abutment height did not influenced zirconia restorations' retentiveness, cement types showed significant differences.

• Restorative Dentistry and Endodontics
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• v.36 no.1
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• pp.37-49
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• 2011

Objectives: The aim of this study was to evaluate the surface color of indirect resin restoration according to the layering placement of different shade of incisal composite. Materials and Methods: In this study, CIE $L^*a^*b^*$ value of 16 Body composite of Tescera ATL (Bisco, Schaumburg IL,USA) was measured by spectrophotometer (NF999, Nippon Denshuku, Japan), and compared to CIE $L^*a^*b^*$ value of Vitapan shade guide. Nine shade Incisal composite of Tescera ATL were buildup to 1 mm thickness on Body composites inlay block, and CIE $L^*a^*b^*$ value was measured. Incisal composite was ground to 0.5 mm thickness and CIE $L^*a^*b^*$ value was re-measured. Color difference between Body composite and Incisal composites layered on Body composite was calculated as a function of thickness. Results: Color difference between corresponding shade of Tescera Body composite and Vitapan shade guide was from 6.88 to 12.80. $L^*$ and $b^*$ value was decreased as layering thickness of Incisal composite on Body composite was increased. But, $a^*$ value did not show specific change tendency. Conclusions: Surface color difference between Body composites and Incisal composites layered on Body composite was increased as the layering thickness of Incisal composite increased (p < 0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.244-249
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• 2015

With the recent progress of digital technology, the computer guided surgery utilizing a guide template in the placement of implant has been actively performed, and the method employing the intraoral scanner at the implant prosthesis introduced. Fabrication method of the guide template can be largely classified into design-related rapid prototyping (RP) system and vector milling system, and each of the method has its own weakness in the clinical application despite of excellent accuracy. Thus, in this case study, a working model was fabricated by the wax RP technology using images acquired by CBCT and an intraoral scanner, and the metal bushing was picked up with orthodontic resin cast upon the wax model. Using this method, a surgical guide template was fabricated and used in surgery. From this, we could obtain a satisfactory outcome clinically in the implant placement and the fabrication of the final prostheses and thus report this case herein.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.1
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• pp.9-20
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• 2023

Purpose: We investigated the effect of open tray impression using pick-up impression coping and close tray impression using transfer impression coping on the accuracy of impression in edentulous patients on their mandibular parts. the effect of material types of pick-up type impression copings for splinting in open tray impression on the accuracy of impression was also evaluated. Materials and Methods: Two implant fixtures were implanted in parallel in the left molar of the mandibular in the shape of a mandibular partial edentulous model. The 40 individual trays were fabricated using 3D printer. The prepared individual trays were classified into 4 groups (i.e., PN, PG, PH, and TN groups), and a total of 40 impression-takings were conducted. A master cast was connected to a Scan Body. The converted STL file was super-imposed on the scan images of the various groups. Results: The order of standard deviation values decreased as follows: PN (0.2343 ± 0.0844 mm), TN (0.2192 ± 0.0840 mm), indicating that the high accuracy of impression for TN group. In addition, for the comparison results between the material types used in splinting the open tray impression, the PH group showed a relatively lower standard deviation (0.1910 ± 0.1176 mm) than that of the PN group (0.2343 ± 0.0844 mm), PG group (0.2556 ± 0.1082 mm). Conclusion: The acrylic resin synthesized by light-induced polymerization exhibited a higher accuracy of impression taking than that of autopolymerizing acrylic resin. Meanwhile, the accuracy of impression taking was not dependent on the implant impression taking method or the presence of connection/fixation of impression copings.