• Journal of Oral Medicine and Pain
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• v.32 no.1
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• pp.91-104
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• 2007

An epidemiologic investigation was carried out to determine the prevalence of symptoms of temporomandibular disorders in college students that aged 19-31 years. 460 students were investigated with a questionnaire from September to December 2006. The obtained results were as follows : 1. The prevalence of symptoms of temporomandibular disorders was 80.6%. 2. The most frequently complained symptom was headache and joint sound was the next one without distinct difference between men and women. 3. While the rate of occurrence of symptom of acute malocclusion decreased with age in men, that of TMJ pain during chewing or speech increased with age in women. 4. Symptoms including TMJ pain during mouth opening, chewing or speech, TMJ fatigue and acute malocclusion occurred significantly more frequently in women than in men. Contributing factors including resting cheeks on hands, stressful state, gum chewing, insomnia and clenching occurred significantly more frequently in women than in men. 5. There was a highly significant relationship between symptoms and contributing factors including resting cheeks on hands, stressful state, unilateral chewing, insomnia and clenching. 6. There was a highly significant relationship between symptoms and general personality.

• Applied Microscopy
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• v.38 no.3
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• pp.259-264
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• 2008

The stabilized $ClO_2$ gas has been used for many years by the food industry as a strong oxidizing and sanitizing agent that has broad and high biocidal effectiveness. Therefore, "stabilized $ClO_2$" gas may be used in fields of disinfectant and sterilization. But, there have been few studies on the decomposition-inhibition effect of stabilized $ClO_2$ gas with passage of time. The main purpose of this study was to examine the decomposition-inhibition effect of stabilized $ClO_2$ gas and the morphological change of kidney by measuring of the light and electron microscope. Sprague-Dawley (SD) rats weighting from 230 gm to 250 gm were used as experimental animals. Under ether anesthesia, the right kidney of rat was obtained. Put each sample in $37^{\circ}C$ and humidity $80{\pm}5%$ incubator, we obtained each sample after 0 day, 1 day, 2 days, 3 days, 4 days and 5 days. We proceeded the observation of light and electron microscope. The results obtained in this study reveal that stabilized $ClO_2$ gas is an effective decomposition inhibitor until 2 days that was conducted at $37^{\circ}C$ and humidity $80{\pm}5%$ conditions.

• Journal of Oral Medicine and Pain
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• v.36 no.1
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• pp.25-37
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• 2011

The purpose of this study is to investigate the relationship between personality type and symptoms and contributing factors of temporomandibular disorders. 199 college students completed the MBTI(Myers-Briggs Type Indicator) and a questionnaire and collected data were analyzed by SAS 9.2 program. The obtained results were as follows : 1. The prevalence of symptoms of temporomandibular disorders and mean scales of positive answers of contributing factors appeared to be higher in I type, S type, T type, P type than in E type, N type, F type, J type. 2. ISTP and ISFP among 16 types of personality seemed to have higher prevalence of symptoms and contributing factors of temporomandibular disorders than other types of personality. 3. Symptom of TMJ pain during mouth opening seemed to occur more frequently in I type, S type, F type, J type than in E type, N type, T type, P type. 4. Contributing factors including clenching and stressful state occurred significantly more frequently in I type than E type. Gum chewing habit occurred significantly more frequently in E type than in I type. 5. Unilateral chewing habit occurred significantly more frequently in J type than in P type. 6. Nervous or sensitive persons had significantly higher mean scales of positive answers of subjective symptoms than relaxed or general persons. 7. General persons had significantly lower mean scales of positive answers of contributing factors than nervous, sensitive and relaxed persons. In conclusion, these results show that there is the relationship between personality and temporomandibular disorders and patient education and counselling considering personality type may contribute to treating patients with temporomandibular disorders.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.335-341
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• 2020

This study examined the shear bond strength between the zirconia core and pressed lithium disilicate veneering ceramics. The Schmitz-Schulmeyer test method was used to investigate the core-veneer shear bond strength of industrially manufactured zirconia core ceramic (Zirtooth, HASS, Gangneung, Korea) and pressed veneer ceramic (IPS e.max Zirpress, Vita PM9, GC Initial IQ, HASS Rosetta SM) (N=40). Data were statistically analyzed using one-way ANOVA and Tukey's test (a=0.05). The fractured surfaces of the specimens were examined to determine the failure pattern using a digital microscope. The mean ± SD shear bond strength in MPa were 16.69±3.11, 14.21±3.63, 11.17±2.92, and 27.90±5.71 for IPS e.max Zirpress, VITA PM9, GC Initial IQ, and HASS Rosetta SM, respectively. The average shear bond strength was largest for HASS Rosetta SM, followed by IPS e.max Zirpress, Vita PM9, and GC Initial IQ(p<0.05). The digital microscopy examination of the fracture surface showed adhesive and cohesive failure in pressed lithium disilicate veneering ceramics. The use of lithium disilicate veneer ceramic produced a significantly higher shear bond strength.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.893-899
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• 2004

Even though Ti-6Al-4V has gained popularity as an implant material, the possible dissolution of Al and V ions in body fluids remains a matter of concern. Though commercially pure Ti (Cp-Ti) overcomes this problem, the mechanical strength of pure titanium remains very low. Thus, in this experiment Cp-Ti was processed by Equal channel angular processing (ECAP), in order to increase the mechanical strength. The biocompatibility of ECAP-Ti, Cp-Ti and Ti-6Al-4V was examined by the apatite formation on each sample surface, after treating the surface with 5M NaOH and soaking in Simulated body fluids (SBF). Initially, the samples were mechanically polished on silicone carbide paper (#2000). The polished samples were treated with 5M NaOH solution at $60^{\circ}C$ for 24 hours. The NaOH treated samples were washed gently with distill water and dried at $40^{\circ}C$ for 1 day. The dried samples were heat treated in air at $600^{\circ}C$ for 1 hour. The surface morphology of these samples were studied using SEM and XRD. The SEM studies showed network of pores in all samples. The XRD showed oxide layer formation on Cp-Ti and Ti-6Al-4V. samples. However the oxide layer in ECAP-Ti was not substantial. These samples were immersed in SBF, kept at $36.5^{\circ}C$ for seven days period. At the end of 7 days, the apatite formation was confirmed only on Cp-Ti and was not observed in Ti-6Al-4V and ECAP-Ti. These observations of apatite formation relate to the fact that Cp-Ti showed greater oxide layer than other samples. The apatite examined was confirmed as tricalcium phosphate (TCP) using EDS and XRD.

• Proceedings of the KACD Conference
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• 2001.05a
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• pp.235-237
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• 2001

;Dentistry has benefited from tremendous advances in technology with the introduction of new techniques and materials, and patients are aware that esthetic approaches in dentistry can change one's appearance. Increasingly. tooth-colored restorative materials have been used for restoration of posterior teeth. Tooth-colored restoration for posterior teeth can be divided into three categories: 1) the direct techniques that can be made in a single appointment and are an intraoral procedure utilizing composites: 2) the semidirect techniques that require both an intraoral and an extraoral procedure and are luted chairside utilizing composites: and 3) the indirect techniques that require several appointments and the expertise of a dental technician working with either composites or ceramics. But, resin restoration has inherent drawbacks of microleakage. polymerization shrinkage, thermal cycling problems. and wear in stress-bearing areas. On the other hand, Ceramic restorations have many advantages over resin restorations. Ceramic inlays are reported to have less leakage than resin restoration and to fit better. although marginal fidelity depends on technique and is laboratory dependent. Adhesion of luting resin is more reliable and durable to etched ceramic material than to treated resin composite. In view of color matching, periodontal health. resistance to abrasion, ceramic restoration is superior to resin restorationl. Materials which have been used for the fabrication of ceramic restorations are various. Conventional powder slurry ceramics are also available. Castable ceramics are produced by centrifugal casting of heat-treated glass ceramics. and machinable ceramics are feldspathic porcelains or cast glass ceramics which are milled using a CAD/CAM apparatus to produce inlays (for example, Cered. They may also be copy milled using the Celay apparatus. Pressable ceramics are produced from feldspathic porcelain which is supplied in ingot form and heated and moulded under pressure to produce a restoration. Infiltrated ceramics are another class of material which are available for use as ceramic inlays. An example is $In-Ceram^{\circledR}$(Vident. California, USA) which consists of a porous aluminum oxide or spinell core infiltrated with glass and subsequently veneered with feldspathic porcelain. In the 1980s. the development of compatible refractory materials made fabrication easier. and the development of adhesive resin cements greatly improved clinical success rates. This case report presents esthetic ceramic inlays for posterior teeth.teeth.

• Journal of Oral Medicine and Pain
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• v.38 no.1
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• pp.7-17
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• 2013

The purpose of this study is to investigate the relationship between personality type and symptoms of oral mucosa disease. 393 college students completed the MBTI(Myers-Briggs Type Indicator) and a questionnaire and collected data were analyzed by SAS 9.2 program. The obtained results were as follows : 1. Dysgeusia(p<0.05) and xerostomia(p<0.01) occurred significantly more frequently in I type than E type. 2. Herpetic stomatitis, recurrent aphthous ulcer, glossitis, dysgeusia, burning mouth syndrome and xerostomia seemed to occur more frequently in S type than in N type. 3. Most symptoms of oral mucosa disease seemed to occur the most frequently in the type including NF among 16 types of personality of MBTI. 4. Most subjects had negative attitude in curing their symptoms of oral mucosa disease(p<.0001). Significantly more subjects with I type than E type had negative attitude in curing herpetic stomatitis(p<0.01) and dysgeusia(p<0.05). 5. Most symptoms of oral mucosa disease appeared to occur the most frequently in nervous or sensitive subjects. Therefore a guideline for the individual cure of oral mucosa diseases meeting personality type is necessary.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.5
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• pp.526-546
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• 2001

Fiber-reinforced composite(FRC) was developed as a structural component for dental appliances such as prosthodontic framework. FRC provides the potential for fabrication of a metal-free, excellent esthetic prostheses. It has demonstrated success as a result of its simple fabrication, natural colour, and marginal integrity, and fracture resistance of veneering composite resin and the FRC material. Although it has lots of merits, clinical and objective data are insufficient. The purpose of this study was to evaluate the fracture strength and the marginal fitness of fiber reinforced composite bridge in the posterior region for clinical application. Sixteen bridges of each group. $Targis/Vectris^{(R)}$, $Sculpture-Fibrekor^{(R)}$, and In-Ceram, were fabricated. All specimens were cemented with Panavia 21 to the master dies. Strength evaluation was accomplished by a universal testing machine (Instron). The marginal fitness was measured by using the stereoscope (${\times}50$). The results were as follows. : 1. The fracture strength according to the materials was significantly decreased in order In-Ceram($238.81{\pm}82$), Targis Vectris($176.25{\pm}18.93$), Sculpture-Fibrekor($120.35{\pm}20.08$) bridges. 2. FRC resin bridges were not completely fractured, while In-Ceram bridges were completely fractured in the pontic joint. 3. The marginal accuracy was significantly decreased in order Targis/Vectris ($60.71{\mu}m$), Sculpture-Fibrekor($73.10{\mu}m$) In-ceram Bridge ($83.81{\mu}m$). 4. The fitness of occlusal sites had a lower value than the marginal sites(P<0.001), and the marginal gaps of inner site of the pontic were greater than that of outer sites of the pontic. Fiber reinforced composite bridges are new, esthetic prosthesis and can be clinically used in anterior regions and short span bridges. However, caution must be exercised when extrapolating laboratory data to the clinical situation because there are no long term clinical data regarding the overall success of the FRC.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.1
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• pp.41-48
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• 2016

Edentulous patients with severe alveolar bone resorption have trouble with using traditional complete denture. In order to overcome these problems, implant-retained overdenture was developed. SFI-bar$^{(R)}$ system can save time and cost compared to other existing bar systems which need complicated laboratory procedures because it can be adjusted directly in a patient's mouth. A 55-year-old male, who had experienced a fractured lower old implant-retained overdenture, wanted a durable and painless denture. The fractured Locator$^{(R)}$ attachments were removed and edentulous mandible was restored with SFI-bar$^{(R)}$. A 77-year-old female with a medical history of the Parkinson's disease and severely absorbed alveolar bone of mandible, wanted to wear a retentive mandibular denture without pain. After placing two implants in front of mental foramen, two adaptors were connected to two implants and a tube bar was connected to the adaptors. A female part fitted to the bar was attached to the new denture. These clinical reports describe two-implant-retained overdenture using the SFI-bar$^{(R)}$ system in mandibular edentulous patients. Since the patients were satisfied esthetically and functionally during 2 years' observation, we would like to report cases.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.361-369
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• 2008

The purpose of this study is to make porous oxide film on the surfaces of pure Ti through anodic spark discharge in electrolytic solution containing calcium and phosphate ions, to improve osseointergration by treating fluoride agent. In addition, it is to evaluate the fluoride modified effect on the surface. Commercial pure Ti plate with $20{\times}10{\times}2mm$ and Ti wire with a diameter of 1.5mm and a total length of 15mm were used. After making titanium oxide films converted by anodic spark discharge, anodizing was performed. Fluoride was spreaded to titanium laboratory plate and maintained for 30 minutes after anodizing breakdown. Fluoride ion discharge amount was measured per 24 hours after dipping titanium plate into saline (10ml) and sustaining 90rpm in a pyrostat. Some plates and wires were dipped in Hanks solutions for a month to examine biocompatibility using SEM and XRD. $TiO_2$ film formed by anodic discharge technique showed great roughness and uniform pores which were $1{\sim}3{\mu}m$ in a diameter. Roughness of the films treated with anodic discharge after blasting were higher than the turned ones(P<0.05). Rapid surface activity was observed in the samples treated with $TiF_3$ agent, which immersed in Hanks solution for 30 days. Taking the results into consideration, the fluoride modified implant with anodic discharge demonstrates that it makes uniformly porous oxide film on the surface of implant and properly increase roughness for osseointegration. The implants will achieve greater bone integration after short healing time by improving surface activity.