• Journal of Oral Medicine and Pain
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• v.33 no.3
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• pp.229-240
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• 2008

Animal mucins have structural characteristics similar to human salivary mucins. Animal mucins have been regarded as suitable substances for saliva substitutes. Since animal mucin molecules in saliva substitutes and host-derived antimicrobial salivary molecules exist simultaneously in whole saliva and the pellicles of patients with dry mouth, interactions may occur between these molecules. The purpose of this study was to investigate the influence of animal mucins on peroxidase activity in solution and on the surface of hydroxyapatite(HA) surfaces. The effects of animal mucins on peroxidase activity were examined by incubating porcine gastric mucin(PGM) or bovine submaxillary mucin (BSM) with either bovine lactoperoxidase(bLPO) or saliva samples. For solid-phase assays, immobilized animal mucins or peroxidase on three different HA surfaces(HA beads, HA disc, and bovine tooth) were used. Peroxidase activity was determined with an NbsSCN assay. The obtained results were as follows: 1. PGM enhanced the enzymatic activity of bLPO in solution phase. PGM did not affect the enzymatic activity of peroxidase in saliva sample(POS). 2. BSM did not affect the enzymatic activities of both bLPO and POS in solution phase. 3. HA-adsorbed PGM increased subsequent bLPO adsorption in all three HA phases. The activity of POS was increased on both the HA beads and bovine tooth. 4. The peroxidase activities on the HA beads and disc were increased when the HA surfaces were exposed to a mixture of bLPO and PGM. 5. The binding affinity of bLPO to PGM was greater than that of bLPO to BSM. Collectively, our results suggest that animal mucins affects the enzymatic activity of peroxidase on the HA surfaces as well as in solution. Saliva substitutes containing animal mucins may affect the function of antimicrobial components in natural saliva and saliva substitutes.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.1
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• pp.1-11
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• 2008

Statement of problem: Over the past decade, increased demand for esthetically pleasing restorations has led to the development of all-ceramic systems. Recent reports suggest that the all-ceramic crowns have excellent physical properties, wear resistance, and color stability. In addition, numerous ceramics have excellent biocompatibility, a natural appearance, and improved physical bonding with resin composite luting agents. However, the brittle nature of ceramics has been a major factor in their restriction for universal usage. Functional occlusal loading can generate stress in the luting agent, and the stress distribution may be affected by the marginal geometry at the finish line. Tooth preparation for fixed prosthodontics requires a decision regarding the marginal configuration. The design dictates the shape and bulk of the all ceramic crowns and influences the fit at the margin. Purpose: The purpose of this study was to evaluate the stress distribution within marginal configurations of all- ceramic crowns (90-degree shoulder, 110-degree shoulder, 135-degree shoulder). Material and methods: The force is applied from a direction of 45 degrees to the vertical tooth axis. Three-dimensional finite element analysis was selected to determine stress levels and distributions. Results and conclusion: The result of stress level for the shoulder marginal configuration was more effective on stress distribution at 135-degree shoulder margin. But the stresses concentrated around at 135-degree shoulder margin. The stress decreased apically at the surface between cements and alumina core, and increased apically at the surface between alumina core and veneering porcelain.

• The Journal of Korean Academy of Prosthodontics
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• v.31 no.4
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• pp.580-610
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• 1993

The purpose of this study was to analyse the deflection and stress distribution at the supporting bone and it's superstructure by the alteration of angulation between implant and it's implant abutment. For this study, the free-end saddle case of mandibular first and second molar missing would be planned to restore with fixed prosthesis. So the mandibular second premolar was prepared for abutment, and the cylinder type osseointegrated implant was placed at the site of mandibular second molar for abutment. The finite element stress analysis was applied for this study. 13 two-dimensional FEM models were created, a standard model at $0^{\circ}$ and 12 models created by changing the angulation between implant and implant abutment as increasing the angulation mesially and distally with $5^{\circ}$ unittill $30^{\circ}$. The preprocessing decording, solving and postprocessing procedures were done by using FEM analysis software PATRAN and SUN-SPARC2GX. The deflections and von Mises stresses were calculated under concentrated load (load 1) and distributed load(load 2) at the reference points. The results were as follows : 1. Observing at standard model, the amount of total deflection at the distobuccal cusp-tip of pontic under concentrated load was largest of all, and that at the apex of implant was least of all, and the amount of total deflection at the buccal cusp-tip of second premolar under distributed load was largest of all, and that at the apex of implant was least of all. 2. Increasing the angulation mesially or distally, the amounts of total deflection were increased or decreased according to the reference points. But the order according to the amount of total deflection was not changed except apex of second premolar and central fossa of implant abutment under concentrated load during distal inclination. 3. Observing at standard model, the von Mises stress at the distal joint of pontic under concentrated load was largest of all, and that at the apex of implant was least of all. The von Mises stress at the distal margin of second premolar under distributed load was largest of all, and that at the apex of Implant was least of ail. 4. Increasing the angulation of implant mesially, the von Mises stresses at the mesial crest of implant were increased under concentrated load and distributed load, but those were increased remarkably under distributed load and so that at $30^{\circ}$ mesial inclination was largest of all. 5. Increasing the angulation of implant distally, the von Mises stresses at the distal crest of implant were increased remarkably under concentrated load and distributed load, and so those at $30^{\circ}$ distal inclination were largest of all.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.5
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• pp.704-723
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• 2000

This study was undertaken to evaluate the tensile bond strength of In-Ceram alumina core treat-ed by ion assisted reaction(IAR). Ion assisted reaction is a prospective surface modification technique without damage by a keV low energy ion beam irradiation in reactive gas environments or reactive ion itself. 120 In-Ceram specimens were fabricated according to manufacturer's directions and divided into six groups by surface treatment methods of In-Ceram alumina core. SD group(control group): sandblasting SL group: sandblasting + silane treatment SC group: sandblasting + Siloc treatment IAR I group: sandblasting + Ion assisted reaction with argon ion and oxygen gas IAR II group: sandblasting + Ion assisted reaction with oxygen ion and oxygen gas IAR III group: sandblasting + Ion assisted reaction with oxygen ion only For measuring of tensile bond strength, pairs of specimens within a group were bonded with Panavia 21 resin cement using special device secured that the film thickness was $80{\mu}m$. The results of tensile strength were statistically analyzed with the SPSS release version 8.0 programs. Physical change like surface roughness of In-Ceram alumina core treated by ion assistad reaction was evaluated by Contact Angle Measurement, Scanning Electron Microscopy, Atomic Force Microscopy; chemical surface change was evaluated by X-ray Photoelectron Spectroscopy. The results as follows: 1. In tensile bond strength, there were no statistically significant differences with SC group, IAR groups and SL group except control group(P<0.05). 2. Contact angle measurement showed that wettability of In-Ceram alumina core was enhanced after IAR treatment. 3. SEM and AFM showed that surface roughness of In-Ceram alumina core was not changed after IAR treatment. 4. XPS showed that IAR treatment of In-Ceram alumina core was enabled to create a new functional layer. A keV IAR treatment of In-Ceram alumina core could enhanced tensile bond strength with resin cement. In the future, this ion assisted reaction may be used effectively in various dental materials as well as in In-Ceram to promote the bond strength to natural tooth structure.

• Korean Journal of Ichthyology
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• v.1 no.1_2
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• pp.83-92
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• 1989

The pharyngeal teeth and the masticatory process of the basioccipital bone were compared in ten species of Korean bitterlings. Three species, Acheilognathus lanceolata, A. limbatus, A. signifier and Rhodeus ocellatus, which are characterized by the absence of serrations on the side of the pharyngeal teeth, are found to, have reduced occlusal grooves on the outside of occlusal margin, Among Korean bitterlings, differences are found in the developmental degrees of the anterior part of the masticatory process, the grooves on the occlusal surface and the chewing area on the pharyngeal first tooth. The occlusal grooves in herbivorous species are considered to be more developed than those in omnivorous species. Considering these findings, the combination of developmental degrees in the three pharyngeal elements suggests generally the phylogenetic relationships among the Korean bitterlings.

• Journal of Periodontal and Implant Science
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• v.41 no.2
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• pp.73-78
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• 2011

Purpose: For periodontal tissue engineering, it is a primary requisite and a challenge to select the optimum types of cells, properties of scaffold, and growth factor combination to reconstruct a specific tissue in its natural form and with the appropriate function. Owing to fundamental disadvantages associated with using a two-dimensional substrate, several methods of seeding cells into three-dimensional scaffolds have been reported and the authors have asserted its usefulness and effectiveness. In this study, we explore the cell attachment of periodontal ligament fibroblasts on nanohydroxyapatite (n-HA) scaffold using avidin biotin binding system (ABBS). Methods: Human periodontal ligament fibroblasts were isolated from the health tooth extracted for the purpose of orthodontic procedure. HA nanoparticles were prepared and $Ca(NO_3)_2-_4H_2O$ and $(OC_2H_5)_3P$ were selected as precursors of HA sol. The final scaffold was 8 mm in diameter and 3 mm in height disk with porosity value of 81.55%. $1{\times}10^5$ periodontal ligament fibroblasts were applied to each scaffold. The cells were seeded into scaffolds by static, agitating and ABBS seeding method. Results: The number of periodontal ligament fibroblasts attached was greater for ABBS seeding method than for static or agitating method (P<0.05). No meaningful difference has been observed among seeding methods with scanning electron microscopy images. However, increased strength of cell attachment of ABBS could be deduced from the high affinity between avidin and biotin ($Kd=10^{-15}\;M$). Conclusions: The high-affinity ABBS enhances the ability of periodontal ligament fibroblasts to attach to three-dimensionally constructed n-HA scaffold.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.5
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• pp.428-433
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• 2004

Sinus floor augmentation has been proven an effective treatment procedure to increase bone volume in the posterior edentulous maxilla. Autogenous bone considered to be the best material for reconstructive bone surgery and has been successfully used as a graft material to augment posterior maxilla. However, the collection of autogenous bone required extra risks for morbidity and complaints. So, various bone graft materials included ${\beta}$-tricalcium phosphate(${\beta}$-TCP) has been introduced for replacing the autogenous bone. The objective of this clinical study was to determine the predictability of endosseous implant placed in a maxillary sinus with ${\beta}$-TCP grafting. We performed sinus elevation with ${\beta}$-TCP to install the implant in the 10 maxillary cases. The prosthetic procedure was performed 6-9 months after. The implant-prosthetics was checked about 1 year. We checked the implant and measured the maximum bite force to evaluate the function of the implant. There was not observed the specific problem and complication in dental implant and maxillary sinus in the grafted materials. The maximum bite force was 558N in case of natural tooth, 365N in implant without grafting, 318N in implant with ${\beta}$-TCP grafting. There was no significant difference between with and without sinus grafting on maximum bite force(p>0.05). As though the long term check-up is needed, the grafting of ${\beta}$-TCP as a osteoconductive materials can expand the volume and induce dense new bone formation in maxillary sinus. So, this short-term results support that ${\beta}$-TCP can be a suitable material for sinus augmentation.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.22 no.1
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• pp.47-55
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• 2013

There have been a great number of developments in clinical techniques and dental materials in dentistry to date. Looking at these developments, while it could be seen that functional elements such as mastication were prioritized rather than aesthetic aspect in the past, aesthetic needs of patients have steadily increased over time and accordingly the aesthetic has become considered a priority in the development of dentistry. Although the first to be considered in discussing the aesthetic in clinical dentistry will be the white aesthetic that is the tooth part of prosthesis, the pink aesthetic that refers to the harmony of such prosthesis with gingiva can be an important consideration not to be ignored aesthetically. However, the harmony with the gingiva often cannot be obtained only by the beautiful prosthesis, and in particular, the pontic and implant areas have poor conditions to achieve the gingival (pink) aesthetic due to the absorption of alveolar ridge compared to natural teeth. Among the most important elements of the gingival aesthetic are the gingival level and the interproximal papilla height. It is very difficult to make the gingival aesthetic in the case of insufficient alveolar ridge, and the recovery of ridge volume and contour is necessary in order to overcome this condition. To this end, the most widely used method is the "connective tissue graft". Many techniques of the connective tissue graft have already been introduced for the ridge augmentation, and each technique has different purposes, and advantages and disadvantages. Rather, due to the excessive amount of techniques, there is confusion about selecting the right technique at a certain time. However, the goal is clear. Ways to increase the success rates must be found, and at the same time, a more favorable way to the gingival aesthetic is to be chosen. Thus, in this study, considerations for the gingival aesthetic that makes harmony and the techniques to achieve it are discussed.

• Journal of Periodontal and Implant Science
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• v.34 no.1
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• pp.71-81
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• 2004

Peri-implantitis could be the result of biomechanical and occlusal overload as well as microbiologic invasion. The dental implant may be more susceptible to dental plaque than the natural tooth, as the predictability of a stable soft tissue attachment complex has not yet been confirmed. With the development of peri-implantitis, the implant surface would be exposed to the oral environment and becomes coated with bacteria. The objective of therapy for this condition is to regain integration of the implant with bone. Since fibroblast adherence to surfaces is impeded by endotoxin, it would seem that decontamination would be desirable to obtain maximum osseointegration. The purpose of this study was to determine whether various chemotherapeutic and mechanical treatments(distilled water, air-powder abrasive, hypersaturated citric acid, tetracycline) can detoxify contaminated titanium implant surface by means of kinetic LAL test. Experimental rough surface titanium disks were fabricated. All of them were divided into two groups(A.a group and P.g group) and each contaminated by A. actinomycetemcomitans and P. gingivalis suspension. Contaminated disks were treated with distilled water, air-powder abrasive, citric acid and tetracycline, and then all disks were placed into LPS-free water for elution. The results were as follows : 1. In A.a group, LPS elute level of all test groups were significantly lower than control group(p<0.05). 2. In A.a group, LPS elute level of test 2, test 3 and test4 groups were significantly lower than that of control group(p<0.05). But, among the test 2, test 3, test4 groups, the significant differences were not detected. 3. In P.g group, LPS elute level of test 2, test 3 and test 4 groups were lower than that of control group(p<0.05). But, among the test groups, the significant differences were not detected. From the result of this study, it would be concluded that air-powder abrasive, hypersaturated citric acid and tetracycline treatments may be effective at reducing endotoxin level on rough titanium implant surfaces, and can be clinically used. But the treatments in peri-implantitis differentially impact osseointegration making one method clinically superior. To gain this knowledges, further molecular biologic and histopathologic studies should be developed.

• Journal of Oral Medicine and Pain
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• v.24 no.2
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• pp.207-217
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• 1999

This study was performed to investigate the effects of clutch adaptation on the mandibular rotational torque movement in normal people. 69 dental students were selected for the study. Their mean age were 23.6 years and they did not present any signs and symptoms of temporomandibular disorders. $BioEGN^{(R)}$ with $Rotate^{(R)}$ program was used to observe and record the amount of mandibular rotational torque on protrusion, on right excursion, on left excursion, and on comfortable wide opening movement. The natural tooth contact movement and the movement with clutch were performed in the above four each mandibular movement. Clutch was made by the method used in $Pantronic^{(R)}$ clutch fabrication. Distance of slant frontal which was translatory trajectory in frontal plane and degree of rotational torque in horizontal and in frontal plane were recorded. The data obtained were processed with SPSSWIN program and the results were as follows : 1. Distance of slant frontal in each mandibular movement generally increased with clutch. 2. Degree of rotational torque in horizontal and in frontal plane on protrusion and on lateral excursions did not increase with clutch, but the degree on wide opening increased with clutch. 3. Degree of rotational torque in horizontal plane on protrusion and on lateral excursions did not show any difference between right and left side, but the degree in frontal plane on protrusion and on lateral excursions showed significant difference between right and left side. 4. Total amount of rotational torque from right and left sides on protrusion and lateral excursions were not increased with clutch, but the degree on wide opening movement was increased with clutch. And in this case, degree in horizontal plane was larger than that in frontal plane. 5. Correlation between total amount of rotational torque in horizontal plane and that in frontal plane were highly significant on protrusion and on lateral excursions with or without clutch, but the significant correlation on wide opening without clutch became not significant with clutch.