• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.344-355
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• 2023

In complete denture fabrication, accurate preliminary impressions are crucial for obtaining an accurate final impression. However, it can be challenging in cases of atypical arch shapes. This case report compares diagnostic casts made with a stock tray and an intraoral scanner (IOS) in a patient with an atypical arch shape. A 58-year-old edentulous male patient with long, narrow, atypical arches was referred to the Oral and Maxillofacial Surgery department for complete denture fabrication. Compared to the diagnostic cast obtained using IOS with adequately captured anatomical parameters, the primary model obtained using a stock tray showed prominent overextended flanges on the labial and buccal sides of the maxillary arch and less prominent overextended flanges in the mandibular arch with pressure spots in the posterior palatal seal area. The custom tray fabricated from such a model required additional adjustment resulting in increased chair time during the final impression procedure.

• Journal of the Korean Society of Radiology
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• v.7 no.1
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• pp.57-62
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• 2013

Despite the many advantages of magnetic resonance imaging in orthopedic prosthetic body image distortion to the differences in the magnetic susceptibility occurs. Attached to the phantom and pork produced by the same $65{\times}15{\times}2mm$ stainless steel and titanium specimen examined the relationship between magnetic resonance imaging and phantom images, the signal intensity changes of the subcutaneous tissue, fat-suppressed quantitative assessment of the degree through the length of image distortion and pig bones. Stainless steel to titanium to 2.8 times 4.4 times in the longitudinal direction than in the direction of the height of large image distortion, signal strength is relatively low 58.5%. Normal 56.2% compared to the subcutaneous tissue, fat-suppressed, were stainless steel 16.04%, 54.53% titanium. Experimental results than the diagnostic value of magnetic resonance imaging (MRI) images of stainless steel with a titanium metal if better could see.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.222-231
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• 2009

Statements of the problem: Over the past decades, conventional complete dentures were used for various patients although they have incomplete function. Overdentures using dental implants could help the improvement of denture function. Purpose: The purpose of this study was to compare the strains of abutment and bone on implant overdenture between splinted and unsplinted type of prosthesis. Additionally, the strain values of parallel placed implant model and unparallel placed implant model were compared. Material and methods: Two acrylic resin model were prepared and two implants were placed at the canine positions in each model. In the first model, two implant were placed parallel. In the second model, two implants were placed with 10 degree labiolingual divergence. Two types of abutment were connected to the fixtures alternatively. One was splint type of Hader bar, the other was unsplint type of ball abutment. Overdentures were fabricated with corresponding attachment systems and seated on abutments. Strains of abutments and labial bone simulants were measured with electric resistance strain gauges when static load from 100 N to 200 N were applied to overdentures. Results: 1. Splinted type of overdentures using bar and clip showed higher absolute strain values. But the strain was compressive and the load was shared by two implants(P<.05). 2. Unsplinted type overdentures using ball and O-ring showed low absolute strain values(P<.05). 3. Labially inclined implant showed higher tensile strain values in unsplinted type of prosthesis than in splinted type of prosthesis. Lingually inclined implant showed rather low strain values under load(P<.05). 4. Non parallel implant model showed higher absolute strain values than parallel placed implant model comprehensively(P<.05).

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.4
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• pp.34-39
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• 2013

For orthopedic artificial metal stainless steel, the magnetization of the magnetic field due to the presence of the titanium was to observe the change. Magnetic field meter (Tesla meters) a certain distance (ISO Centre) 1.5 Tesla magnetic field, the magnetization in the center with the passage of time were measured. Therefore, these artificial metal clip shape and magnetization of the sample size to produce a ferromagnetic material for comparison is the experimental dependence. For comparison of the experimental dependence of the magnetization, thereby producing a test piece size such as shaping prosthetic metal Clip is a ferromagnetic material. The experimental results, the metal orthopedic implants, there was no change in the magnetization indicated by ferromagnetic material in its natural state. However, in a magnetic field of 1.5T (Tesla), showed a sensitivity that is magnetized rapidly compared to the ferromagnetic material. In conclusion, high in the order of Clip, Stainless, of Titanium, the degree of dependence of the magnetization intensity of magnetization was the order Stainless, Titanium, of Clip in a magnetic field.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.115-120
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• 2012

Metals used orthopedic in human magnetic resonance imaging scan of the metal to be inserted, The information to users about the image distortion is to propose a basis for judgment. Metals used orthopedic on Stainless, Titanium and Clip using ferromagnetic artifacts and distortion of the image were measured. Using Phantom "Effect of Metals used in Orthopedic on Magnetic Resonance ImagingI" pig in a paper subsequently was carried out using the same bone. Experimental results using a pure Titanium is a relatively high diagnostic value was found that.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.46-50
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• 2012

Stainless steel and titanium used for orthopedic prosthetic metal, magnetic resonance imaging was measured quantitatively the extent of distortion. Based on reading tests at varying metal magnetic resonance imaging (MRI) were investigated. To two image acquisition conditions for having three metal bodies mutually quantitative it compared analyzed the image of cross direction and the image of lengthwise. As for the distortion of the magnetic resonance image, as for the distortion of image it became small in the order of Clip, Strainless and Titanium. In addition, with T1WI and T2WI which are image acquisition condition T2WI the distortion of image became small. As for the distortion of the image by the metal, you could see the distortion of image in elliptical shape, the metal a bigger image distortion appeared in many parts. If clinical doctor has the condition of the same operation, use the Titanium material, it can, raising the diagnostic value of magnetic resonance image inspection after the operating from Stainless.

• Journal of radiological science and technology
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• v.35 no.4
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• pp.321-326
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• 2012

Used as an ingredient in the hospital for orthopedic prosthetic stainless and titanium metal the same size as on the MRI diagnostic value of imaging were compared. Center of images, background high band portion of the video signal is converted into a weighted intensity values Normal images and compared. The area of normal slice and also the distortion of images and cross-sectional imaging of a range of quantitative and sagittal planes were compared. As a result, the periphery high band signal intensity values of Stainless video phantom 2, pig bone 1.8, Titanium imaging of phantom 1.7 has higher value than Normal video pig bone 1.3 times the signal strength rivers. MRI distortion of the shape and the distortions of the range, if the cross-sectional area compared to Normal Slice Stainless case of phantom 65.8 %, pig bone 61.5 %, Titanium distortion phantom 23.1 %, pig bone 38.5 % of the range of community found. In this experiment, as a result, MRI was found to be Titanium more diagnostic value than the specimen with respect to the signal intensity weighted value and low distortion range, Stainless.

• Journal of the Korean Society of Radiology
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• v.13 no.2
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• pp.227-232
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• 2019

MRI examination for patients with metal objects has in poor image quality. Metallic implants can result in poor image because magnetic susceptibility causes signal loss and distortion and makes poor imaging, which is called magnetic susceptibility artifact or metal artifact. There are several approaches to reduce metal artifacts. In this study, we study the reduction of metal artifact by VAT and SEMAC techniques. A metal implant used for orthopedic surgery was attached to the phatom and the distortion caused by the artifact was measured under T1WI and T2WI protocols. Several techniques of VAT only and VAT and SEMAC for the reduction of metal artifact were compared. The metal artifact showed a reduction of at least 8% to a maximum of 26% in the VAT-SEMAC. The VAT-SEMAC technique can be applied to patients with orthopedic implants to improve image quality. If scan time and image quality are simultaneously considered in VAT-SEMAC technique, metal artifact will be reduced in clinical practice.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.6
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• pp.42-47
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• 2012

Followed by a paper on the Pig and Bone orthopedic prosthetic, this experiment using Phantom and Bone MRI imaging I, II of orthopedic prosthetic metal effect combines magnetic resonance imaging on metal signal-to-noise ratio(Signal to noise : SNR) and CNR(Contrast to noise: CNR), fat signal suppression(Fat-suppression) images was compared. Specimen trees to measure the reliability of the experimental reproducibility tests and statistical analysis using the SPSS statistical package was applied program SPSS(IBM SPSS Statistice 19) by * P = 0.000 < significance level $({\alpha})$ = 0.01 as a significant there was a correlation(** P < 0.01). SNR and CNR results did not directly proportional to the Titanium, Stainless, Clip CNR and fat signal suppression of the order of images of blood specimens was found to be close to the image. The impact of orthopedic prosthetic metals on magnetic resonance imaging in the diagnostic value of Titanium is relatively high and are meant more.

• The Journal of Korean Academy of Prosthodontics
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• v.27 no.2
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• pp.79-100
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• 1989

The Purpose of this study was to investigate material differences in stress transmission among various artificial teeth and denture base materials. For this study, a two-dimensional finite element model and a two-dimensional photoelastic model of a mandible with complete denture were made. A resin tooth and a porcelain tooth were used as artificial teeth, and a resin base, a metal lined base, and a soft-liner lined base were used as denture bases. An occlusal load was applied and principal stresses generated in the supporting tissues were compared. To test the impact stress transmission, strain gauge attached to the denture base specimens made of the different materials were made in thick and thin groups. Voltage outputs from hitting the specimen with a steel ball were compared. The results were as follows : 1. In FEM, increasing the mucosal thickness reduced the maximum principal stresses in the supporting tissues, but altering the tooth materials and the base materials induced no difference in the stresses. 2. In photoelastic model study, no difference in fringe order among the specimens were observed, but the thick mucosa group and the soft-liner lined group revealed a more uniform distribution of the load. 3. In strain measuring, the impact force transmission was highest in the soft-liner lined group, and was the lowest in the metal lined group(p<0.01). 4. In the thin group using the resin base, the porcelain tooth showed higher impact stress transmission than the resin tooth(p<0.01), but no difference was observed between them in the thick group. In the soft-liner lined group, the porcelain tooth showed higher impact stress transmission than the resin tooth(p<0.01), but no difference was observed between them in the metal lined group. 5. The thick group showed lower impact stress transmission than the thin group(p<0.01).