• The Journal of Korean Academy of Prosthodontics
• /
• v.48 no.1
• /
• pp.28-40
• /
• 2010

Purpose: The aim of this retrospective study was to provide long-term data about the correlation between multifactorial local factors and the survival of implants. Material and methods: During 19 years (1991 to 2009), 2796 implants were placed in 879 patients. From dental charts and radiographs, the following data were collected: patient's age at implant placement, gender, implant system, surface, length, diameter, location of implant placement, bone quality, primary stability, type of prosthesis. The correlations between these data and implant survival were analyzed. Statistical analysis was performed using Kaplan-Meier survival analysis, Chi-square test, odds ratio. Results: 1. Among the 2796 implants, 150 implants failed that resulted in a cumulative survival rate of 94.64%. The cumulative survival rate of smooth surface implants (91.76%) was lower than rough surface implants (96.02%). 2. Anatomic location, implant surface, diameter of smooth surface implant, primary stability, type of prosthesis, patient's age and gender were significantly associated with implant survival (P < .05). 3. No significant difference in implant survival was found in relation to the following factors: implant length, bone quality, diameter of rough surface implants and type of rough surface according to implant manufacturer (P < .05). Conclusions: Local factors such as anatomic location, implant surface, diameter of smooth surface implant, primary stability and type of prosthesis have a significant effect on implant survival.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.31 no.4
• /
• pp.636-644
• /
• 2004

Recently, self-etching adhesive system have been developed and bonding procedures simplified into one or two steps, which are simultaneously applied to both enamel and dentin. These systems are easy to use and have the potential for good clinical success. The purpose of this study is to evaluate in vitro the microleakage on the cementum/dentin and enamel walls in composite resin restoration of Class V cavities, regarding the use of different adhesive systems. 30 human premolars were divided into 3 groups. A standardized Class V preparation was prepared on the buccal and lingual surface of each premolar. The preparation were made parallel to the cementoenamel junctions, with the gingival half of the preparation extending 1mm apical to the cementoenamel junction. After adhesive system was applied to teeth as manufacture's recommendation, hybrid resin composite was filled in bulk into the preparation and light polymerized according to manufacturer's recommendations. Specimen were stored in distilled water at $37^{\circ}C$ for 5 days and thermocycled 1000 times ($5^{\circ}C{\pm}2^{\circ}C\;and\;55^{\circ}C{\pm}2^{\circ}C)$, then immersed in a 2% methylene blue solution for 12 hours. After sectioning mesio distally through the restorations, the degree of dye penetration was scored under a stereomicroscope at ${\times}\;25$ magnification. The data were analyzed statistically using t-test and one-way ANOVA. The results were as follows: ${\cdot}$ There is no adhesive system which can prevent microleakage perfectly. ${\cdot}$ There is significant difference in microleakage between enamel margin and dentin margin (p<0.0001). ${\cdot}$ In enamel margin, self-etching primer systems did not show any significant difference comparing total-etching system. In denin margin, self-etching primer systems did not show any significant difference comparing one-bottle adhesive system used in combination with total-etching.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.37 no.1
• /
• pp.44-52
• /
• 2010

The objective of this in vitro study was to detect and monitor demineralization and remineralization of primary teeth according to restorative materials using quantitative light-induced fluorescence (QLF). A single bur hole was drilled on the each sound forty eight primary anterior teeth, and the specimens were divided into three groups. The cavity was restored with $Filtek^{TM}$ Z250(Group 1), F2000(Group 2), $Ketac^{TM}$ N100(Group 3) following the manufacturer's instructions. The teeth were subjected to the demineralizing buffer for 3 days, and then subjected to a remineralizing buffer for 14 days. The change of mineral loss(${\Delta}Q$) according to the stages was evaluated by QLF and the following results were obtained: 1. When demineralization was done, ${\Delta}Q$ was increased as follows. : Group 1 ($-110.79\;{\pm}\;27.77$) < Group 2 ($-104.84\;{\pm}\;28.95$) < Group 3 ($-90.16\;{\pm}\;21.87$) : Resistance to demineralization was statistically significant in Group 3. 2. There was a statistically significant increase in ${\Delta}Q$ of all groups since 1st day of remineralization 3. The rate of remineralization, ${\Delta}$(${\Delta}Q$)/day, showed significant high value in each group on the 1st day then decreased rapidly. 4. There was no statistically significant difference in the degree of remineralization among restorative materials.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.24 no.4
• /
• pp.325-335
• /
• 2008

The junction between resilient denture liner and the denture base is difficult to finish and polish due to difference of the physical property of the materials. Gaps tend to be formed during finishing and polishing procedures. The purpose of this study was measuring the width of junctional gap between $Molloplast-B^{(R)}$ and denture base material after finishing and polishing procedure, and evaluating the effect of method and direction on gap width. $Molloplast-B^{(R)}$ was processed (according to the manufacturer's instruction) against Lucitone $199^{(R)}$ acrylic resin. 50 specimens were fabricated with a raised center section. All of specimens were examined and photographed with a stereoscopic microscope(x120), and the largest gap along the junction of $Molloplast-B^{(R)}$ and acrylic resin on each specimen was measured. One-way analysis of variance(ANOVA) and independent t-test at 95% confidence level were used to analyze the data and to compare groups. The results of this study were as follows. In comparison with finishing tools, the gap width was the largest in $Molloplast^{(R)}$-Cutter and the smallest in FSQ-cross cut bur. There was statistically significant difference between FSQ-cross cut bur and $Molloplast^{(R)}$-Cutter(p<0.05). There was no significant difference in gap width between the direction of polishing. The mean value of gap width was the smallest in case of no polishing, and the largest in case of polishing with pumice & tin oxide. There was statistically significant difference between pumice and pumice & tin oxide. From the results, it is concluded that the use of $Molloplast^{(R)}$-Cutter in clinic need serious consideration even though it has good cutting ability. Further careful study is needed for finishing and polishing methods for decreasing gap width in junction of two materials.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.27 no.2
• /
• pp.197-207
• /
• 2011

The study aimed at examining how different reline resins affect flexural strength and flexural modulus of denture base. A total of 80 specimens ($64{\times}10{\times}3.3$ mm, according to ISO 1567:1999) of heat-polymerized resin, 40 specimens for (Lucitone199(Dentsply Int., NewYork, USA), SR Ivocap(Ivoclar AG, Schaan, Liechtenstein)) respectively, were polymerized according to the manufacturer's instructions and divided into eight groups(n = 10). Control group specimens remained intact. Specimens in the other groups were abraded on both sides to 2 mm thickness, and were relined in 1.3 mm thickness with 3 types of resins (Lucitone199(Dentsply), SR Ivocap(Ivoclar), and Rebase II(Tokuyama Co., Ltd, Tokyo, Japan)). All specimens were preserved in distilled water at $37^{\circ}C$ for 50 hours, and then were subjected to flexural strength testing in a universal testing machine using 3-point loading. A crosshead speed of 5 mm/min was used, and the distance between the supports was 50 mm. Data analyses included one-way analysis of variance(ANOVA) and the Tukey Honestly Significant Difference test (p=.05). Both heat-polymerized resin groups and auto-polymerized resin groups showed statistically low flexural strength and flexural modulus than control groups. Specimens relined with Lucitone 199 showed significantly higher flexural strength and flexural modulus than those relined with SR-Ivocap. Specimens relined with auto-polymerized resin showed significantly lower flexural strength and flexural modulus than those relined with heat-polymerized resin. Relining with heat-polymerized resins showed superior mechanical properties to relining with an auto-polymerized resin. Relining with the same heat-polymerized resin as the denture base does not affect mechanical properties of a denture. Lucitone199 using a compression-mould technique resulted in the highest flexural strength.

• Restorative Dentistry and Endodontics
• /
• v.32 no.3
• /
• pp.169-179
• /
• 2007

This study was to compare the microshear bond strength $({\mu}SBS)$ of light- and chemically cured composites to enamel coupled with four 2-step self-etch adhesives and also to evaluate the incompatibility between 2-step self-etch adhesives and chemically cured composite resin. Crown segments of extracted human molars were cut mesiodistally, and a 1 mm thickness of specimen was made. They were assigned to four groups by adhesives used: SE group (Clearfil SE Bond) AdheSE group (AdheSE), Tyrian group (Tyrian SPE/One-Step Plus), and Contax group (Contax) Each adhesive was applied to a cut enamel surface as per the manufacturer's instruction. Light-cured (Filtek Z250) or chemically cured composite (Luxacore Smartmix Dual) was bonded to the enamel of each specimen using a Tygon tube. After storage in distilled water for 24 hours, the bonded specimens were subjected to ${\mu}SBS$ testing with a crosshead speed of 1 mm/minute. The mean ${\mu}SBS$ (n=20 for each group) was statistically compared using two-way ANOVA, Tukey HSD, and t test at 95% level. Also the interface of enamel and composite was evaluated under FE-SEM. The results of this study were as follows ; 1. The ${\mu}SBS$ of the SE Bond group to the enamel was significantly higher than that of the AdheSE group, the Tyrian group, and the Contax group in both the light-cured and the chemically cured composite resin (p < 0.05). 2. There was not a significant difference among the hdheSE group, the Tyrian group, and the Contax group in both the light-cured and the chemically cured composite resin. 3. The ${\mu}SBS$ of the light-cured composite resin was significantly higher than that of the chemically cured composite resin when same adhesive was applied to the enamel (p < 0.05). 4. The interface of enamel and all 2-step self-etch adhesives showed close adaptation, and so the incompatibility of the chemically cured composite resin did not show.

• Restorative Dentistry and Endodontics
• /
• v.29 no.2
• /
• pp.177-184
• /
• 2004

Objectives : This study investigated the hypothesis that increasing light-curing time would leave the oxygen-inhibited layer (OIL) of the adhesive thinner, and in turn, result in lower shear bond strength (SBS) than those obtained by the routine curing procedures. Methods：120 human extracted posterior teeth were randomly divided into three groups for bonding with three adhesives：All Bond 2/sup (R)/, One Step/sup (R)/, and Adper Prompt/sup (R)/. They were subsequently divided into four subgourps with different light-curing time (10, 20, 30 and 60s). The assigned adhesives were applied on superficial occlusal dentin according to the manufacturer's instructions and cured with one of the four curing times. Composite resin cylinder, 2.35㎜ in diameter, were built on the cured adhesive and light-cured for 40s. SBS were measured after 24h from the bonding using a universal testing machine (crosshead speed 1.0 ㎜/min). The relative thickness of the OIL and the degree of conversion (DC) were determined from the adhesive on a slide glass using FT-NIR in an absorbance mode. Data were analysed with One-way ANOVA and Duncan's multiple test (p〈0.05), Results：With increasing cure time, although there were no significant difference in th SBS of One-step and Adper Prompt (p〉0.05), those of All Bond 2 decreased significantly (p〈0.05). The relative thicknesses of the OIL on each adhesive were not affected by the cure time (p〉0.05). Although the DC of All-Bond 2 were statistically not different with increasing cure time (p〉0.05), those of One-Step and Adper Prompt showed an increasing trends with increasing cure time (p〈0.05). Conclusions：Increasing light-curing time did not affect on the relative thickness of the OIL of the adhesives, and in turn, on the SBS to dentin.

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

• Restorative Dentistry and Endodontics
• /
• v.32 no.4
• /
• pp.356-364
• /
• 2007

The purpose of this study was to assess the background color-interceptive ability ana opacity of opaque shade composites (Universal composite, Filtek Z350, Charisma, Clearfil ST, Palpaque Estelite, Esthet-X, and Metafil Flo). Twenty four background specimens (diameter 5.5 mm, thickness 3.0 mm) with Root dentin Mustard (Bisco, Schaumburg, IL, USA) were made. The CIE $L^*a^*b^*$ value of background specimens was measured by a spectrophotometer (Spectrolino, GretagMacbeth, Regensdorf, Switzerland). Three specimens in every group were filled on the background specimens. The surface color of samples was measured by a spectrophotometer in 3.0 mm and every thickness to 0.5 mm while grinding. The color difference in the background color along with 3.0 mm specimen gauged the masking effect in each thickness while grinding and polishing. The opacity was calculated in 1 mm thick specimens. The opacity was in the decreasing order of Clearfil ST, Metafil Flo, Filtek Z350, Palpaque Estelite, Universal composite, Charisma, and Esthet-X (p < 0.05). As the thickness get reduced, $L^*$ value showed decreasing, $a^*$ increasing tendency. The surface color difference between pair of the 3.0 mm thick specimen and after grinding in same opaque resin was above 3.3 except Clearfil ST and Metafil Flo. The color difference (${\Delta}E^*$) between pair of background specimen and opaque resin built-up specimen showed more than 10.0 regardless kinds and thickness. The variance in opacity characteristics and color of the opaque composites is dependent upon manufacturer. When using the opaque resin, the optical properties of each material must be considered as well as cavity.

• Vending industry
• /
• v.2 no.5 s.6
• /
• pp.56-62
• /
• 2002

담배자판기의 신규설치를 금지하고 기존 설치된 자판기마저 전면철거하도록 하는 보건복지부의 초강력 규제안이 마침내 철회가 되게 되었다. 보건복지부는 올 들어 확대되는 금연정책에 편승, 기존 흡연 구역 내 담배자판기 신규설치를 금지하고, 기존 설치된 제품들마저 전면철거하는 규제를 담은 국민건강증진법 시행령 개정안을 지난 4월 공고하며 그 입법추진을 진행한 바 있다. 이 공고안은 그간 국무총리실 산하 규제개혁위원회 분과위원회에 상정되어 1,2차 심의를 진행해 오다 지난 9월 27일 본회의를 통해 '보건복지부의 흡연구역 내 담배자판기 신규설치 금지 및 기존 자판기 철거는 명백히 영업활동 자유 및 재산권 침해에 해당된다.'는 이유로 이를 철회토록 하는 결정을 진행했다. 이 결정을 담은 국민건강증진법 개정안은 조만간 법제처 심사 및 차관회의 등을 거쳐 최종 확정 되게 된다. 이같은 규제개혁위원회의 결정은 협회를 중심으로 한 산업의 적극적인 대응이 있었기에 가능했다. 성인인증장치 도입을 통해 청소년 흡연문제를 완전, 해결하겠다는 산업계의 적극적인 자율대책에도 불구하고 아예 담배자판기를 뿌리 채 뽑겠다는 보건복지부의 행정만능주의적인 발상은 도저히 수용하지 못할 부당한 처사라는 데 관련업계가 인식을 같이 했다. 따라서 이를 반대하는 산업계 입장을 분명히 하며 분명히 하며 적극적인 저지 대응을 최근까지 진행해 왔다. 협회에서는 1차적으로 보건복지부 건강증진과에 담배자판기 전면철거에 대한 산업계 반대 입장을 피력하는 소견서 제출하고 적극적인 산업계의 반대의지를 피력하는 작업을 진행했다. 또한 청소년보호위원회를 통해 청소년 흡연감소를 위한 성인인증 담배자판기 설치 활용방안 건의하며 담배자판기의 긍정적인 활용측면을 집중 부각시키기도 했다. 재정경제부를 통해서는 담배사업법 관련 담배자판기 설치기준에 대한 질의를 통해 현행 관련법 내에서의 설치기준을 명확히 하기도 했다. 이같은 대응에 있어서의 핵심 설득 논리는 담배자판기가 이제는 성인인증장치 부착을 통해 청소년 및 사회적 위해 요인을 극소화 할 수 있다는 점에 있었다. 과거와는 달리 담배자판기가 오히려 청소년의 담배 구입루트 차단이라는 긍정적 역할을 할 수 있는 시점에 있어 이를 전면규제하기보다는 합법적인 설치 환경을 확보하여 사회적으로 떳떳하게 존재가치를 평가받을 수 있게 해달라는게 산업계의 초지일관의 주장이었던 것. 협회는 이같은 주장이 결코 산업계의 이기만이 아니라 세계적인 추세라는 점, 또 담배자판기를 전면철거까지 하면서 과당규제를 할 명분이 부족하다는 점을 반대논리로 적극 내세웠다. 규제개혁위원회가 이번 공공 이용시설 중 흡연구역으로 지정된 장소 내에 담배자판기는 설치 금지 및 철거규제에 철회권고를 내리게 된 것은 이러한 산업계의 주장을 적극 수용함에 힘입은 바 크다. 규제개혁위원회는 이번 결정의 주된 이유로 우선 기설치된 자판기에 대한 철거는 재산권 침해로 위헌 소지가 있음을 들고 있다. 또한 흡연자를 위한 흡연구역내에서마저 자판기 설치를 금지하는 등의 규제는 과도하며 흡연자의 권익보호 역시도 필요함을 인정하고 있다. 따라서 전면적인 규제보다는 청소년 이용통제 가능한 흡연구역에 한하여 담배자판기를 설치토록한 현행규정의 실질적 관리를 강화하며, 전체적으로 흡연구역을 축소 제한하는 방향으로 추진함이 바람직하다는 의견을 제시했다. 규제개혁위원회의 이번 결정으로 흡연구역 내 담배자판기의 설치는 현행법의 적용을 받게 되며, 산업계의 자율대책대로 성인인증 장치를 부착한 담배자판기의 설치 확대가 크게 촉발될 수 있을 것으로 기대된다. 담배자판기가 적극적이고 능동적인 사회적 역할을 할 수 있을 때 자연 이를 반대할 수 있는 명분도 약해질 수 밖에 없다. 산업계는 보다 신뢰성 있게 청소년 이용을 차단할 수 있는 담배자판기 관련 기술 수준을 향상시켜야 할 것이며, 협회에서는 담배자판기의 공공성과 역할에 대한 지속적인 계몽 홍보를 통해 소비자 인식을 고양시켜 나갈 수 있게 해야 할 것이다. 비록 전면 규제 완화가 어렵고 힘든 길이기는 하지만 소비자에게 신뢰성을 부여하고 청소년의 담배 구입 루트 차단에 혁혁한 역할을 다할 수 있게 된다면 그 입지기반을 재평가 받을 수 있게 될 것이다. 담배자판기의 내일은 이제 암울함이 아닌 서서히 희망을 비치는 쪽으로 급선회되고 있다.