• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.15 no.1
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• pp.13-20
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• 1985

The author obtained the oblique lateral trans cranial radiograms from 376 patients (114 of male, and 262 of female) with temporomandibular joint arthrosis. After tracing each film, the author analyzed the dimensional changes of the condylar heads with pain, clicking, mouth opening limitation, and masticatory difficulty respectively, which were the chief complaints of the TMJ arthrosis and compared these data with control group. The results were as follows; 1. There was a great predilection for occurrence of the TMJ arthrosis in female (262 cases) over male (114 cases). But there was no significant difference in ratio between the sexes on each symptom. In male, 60 patients (52.6%) had pain, 28 patients (24.6%) had clicking, 21 patients (18.4%) had mouth opening limitation, and 5 patients (4.4%) had masticatory difficulty. In female, 148 parients (56.5%) had pain, 57 patients (21.8%) had clicking, 47 patients (17.9%) had mouth opening limitation, and 10 patients (3.8%) had masticatory difficulty. 2. Examined controlled group, the author analyzed the dimension of W-W', 0-H, 0-A, 0-B on the right side first, and left side second. In male, the dimension of W-W' was 14.52㎜, 14.13㎜; 0-H was 13.92㎜, 13. 71㎜' 0-A was 8.91㎜, 9.0㎜ and 0-B was 8.67㎜, 8.78㎜. In female, W-W' was 13.77㎜, 13.51㎜; 0-H was 13.42㎜, 13.35㎜; 0-A was 8.92㎜, 9.01㎜; and 0-B was 8.59㎜, 8.80㎜. 3. W-W' and 0-H of the experimental group were distinctly lesser than the controlled group. Male with mouth opening limitation show the least (12.70㎜, 13.00㎜) on W-W', but both sexes with pain show the least on 0-H. There was no significant difference between experimental group with Clicking and controlled group on 0-H, 0-A, and 0-B. And also there was no difference on 0-B in patients with every symptom except masticatory difficulty. The dimensional changes of the condylar heads with those symptoms were as follows; a) In male patients, complaing of pain, W-W' of the right and left was 13.80㎜, 12.80㎜; 0-H was 13.10㎜, 12.90㎜; 0-A was 8.69㎜, 8.18㎜; 0-B was 8.33㎜, 8.42㎜. In female, W-W' was 13.01㎜, 12.90㎜; 0-H was 12.48㎜, 12.80㎜; 0-A was 8.60㎜, 8.49㎜; 0-B was 8.48㎜, 8.50㎜. b) In male patients with clicking, W-W' was 13.70㎜, 13.10㎜; 0-H was 13.90㎜, 13.10㎜; 0-A was 8.81㎜, 8.16㎜ 0-B was 8.34㎜, 8.25㎜. In female, W-W' was 13.10㎜, 13.50㎜; 0-H was 13.30㎜, 12.91㎜; 0-A was 8.95㎜, 8.49㎜; 0-B was 8.23㎜, 8.70㎜. c) In male patients with mouth opening limitation, W-W' was 12.70㎜, 13.00㎜; 0-H was 13.40㎜, 13.40㎜; 0-A was 8.37㎜, 8.48㎜; 0-B was 8.33㎜, 8.62㎜. In female, W-W' was 13.00㎜, 12.50㎜ 0-H was 12.90㎜, 13.10㎜; 0-A was 8.49㎜, 8.09㎜; 0-B was 8.77㎜, 8.01㎜. d) In male patients with masticatory difficulty, W-W' was 13.30㎜, 13.20㎜; 0-H was 13.40㎜, 12.60㎜; 0-A was 8.26㎜, 8.32㎜; 0-B was 7.80㎜, 8.20㎜. In female, W-W' was 12.30㎜, 12.00㎜; 0-H was 13.10㎜, 13.20㎜; 0-A was 8.68㎜, 7.95㎜; 0-B was 7.46㎜, 7.87㎜.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.23 no.1
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• pp.34-40
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• 2014

There are several treatment options for rehabilitation of partial edentulism including the use of conventional or implant-retained fixed prostheses. However, such prosthetic options cannot always be possible because of compromised general and oral health (i.e. loss of supporting tissues, medical reasons, extensive surgical protocol and osseointegration failure of dental implant) as well as the affordability of patients. In some cases, removable partial denture provides easier access for oral hygiene procedures and the ability to correct discrepancies in dental arch relationships than implant fixed prosthesis. Recently, Implant Supported Removable Partial Denture (ISRPD) where to place dental implant in strategic position has been suggested to improve the limitation and shortcomings of conventional RPD. ISPRD can overcome mechanical limition of conventional RPD by placing implant in a favorable position and can be cost-effective, prosthetic solution for partially edentulous patients who are not immediate candidates for extensive, fixed implant supported restorations. Incorporation of dental implants to improve the RPD support and retention and to enhance patient acceptance should be considered when treatment planning for RPD. In this case, 59 years old male patient who received dental treatment of implant fixed prosthesis on both side of the upper jaw and implant overdenture on lower jaw showed implant abutment screw fracture on #15i and osseointegration failure on multiple number of implants. After removing failed implants, we planned ISRPD using #15i,24i,25i,26i and #23 natural tooth for RPD abutment. We fabricated #23 surveyed crown,#24i=25i=26i surveyed bridge and #15i gold coping for support,retention and stability for RPD. Periodic follow up check for 2years has been performed since the ISRPD delivery to the patient. No sign of screw loosening, fracture or bone resorption around abutment implants were detected.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.136-147
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• 2009

Statement of problem: Since the introduction of the concept of osseointegration in dental implants, high long-term success rates have been achieved. Though the use of dental implants have increased dramatically, there are few studies on domestic implants with clinical and objective long-term data. Purpose: The aim of this retrospective study was to provide long-term data on the $Implantium^{(R)}$ implant, which features a sandblasted and acid-etched surface and internal connection with microthreads. Material and methods: 106 $Implantium^{(R)}$ implants placed in 38 patients at Yonsei University Hospital were examined to determine the effect of various factors on implant success and marginal bone loss, through clinical and radiographic results during a 6 to 30 month period. Results: 1. Out of a total of 106 implants placed in 38 patients, one fixture was lost, resulting in a 99.1% cumulative survival rate. 2. Among the 96 implants which were observed throughout the study period, the survival rates were 97.0% in the maxilla and 100% in the mandible. The survival rate in the posterior regions was 98.9% and 100% in the anterior regions. 3. The mean bone loss during the first year after prosthesis placement was 0.17 mm, while the mean annual bone loss after the first year was 0.04 mm, which was statistically less than during the first year(P<.05). 4. There was no significant difference in marginal bone loss according to age during the first year(P>.05), but after the first year, the mean annual bone loss in patients above 50 years was significantly greater(P<.05) compared with patients under 50 years. 5. No significant difference in marginal bone loss was found according to the following factors: gender, jaw, location in the arch, type of implant(submerged or non-submerged), presence of bone grafts, type of prostheses, and type of opposing dentition(P<.05). Conclusion: Based on these results, the sole factor influencing marginal bone loss was age, while factors such as gender, jaw, location in the arch, type of implant, presence of bone grafts, type of prostheses and type of opposing dentition had no significant effect on bone loss. In the present study, the success rate of the $Implantium^{(R)}$ implant with a SLA surface and internal connection with microthreads was satisfactory up to a maximum 30 month period, and the marginal bone loss was in accord with the success criteria of dental implants.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.148-155
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• 2009

Statement of problem: The interest in all-ceramic restorations has increased as more techniques have become available. With the introduction of machinable dental ceramics and CAD/CAM systems there is a need to evaluate the quality levels of these new fabrication techniques. Purpose: This study is to evaluate the crown fidelity(absolute marginal discrepancy and internal gap) of various zirconia-based all-ceramic crowns fabricated with different CAD/CAM(computer-assisted design/computer-assisted manufacturing) systems and conventional cast metal-ceramic crowns. Material and methods: A resin tooth of lower right second premolar was prepared. After an impression was taken, one metal master die was made. Then 40 impressions of metal master dies were taken for working dies. 10 crowns per each system were fabricated using 40 working dies. Metal-ceramic crowns were cast by using the conventional method, and Procera, Lava, and Cerec inLab crowns were fabricated with their own CAD/CAM manufactruing procedures. The vertical marginal discrepancies and internal gaps of each crown groups were measured on a metal master die without a luting agent. The results were statistically analyzed using the one-way ANOVA and Tukey's HSD test. Results: 1. Vertical marginal discrepancies were $50.6{\pm}13.9{\mu}m$ for metal-ceramic crowns, $62.3{\pm}15.7{\mu}m$ for Procera crowns, $45.3{\pm}7.9{\mu}m$ for Lava crowns, and $71.2{\pm}2.0{\mu}m$ for Cerec inLab crowns. 2. The Internal gaps were $52.6{\pm}10.1{\mu}m$ for metal-ceramic crowns, $161.7{\pm}18.5{\mu}m$ for Procera crowns, $63.0{\pm}10.2{\mu}m$ for Lava crowns, and $73.7{\pm}10.7{\mu}m$ for Cerec inLab crowns. Conclusion: 1. The vertical marginal discrepancies of, 4 crown groups were all within the clinically acceptable range($120{\mu}m$). 2. The internal gaps of LAVA, Cerec inlab, and metal-ceramic crowns were within clinically acceptable range except Procera crown($140{\mu}m$).

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.99-107
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• 2009

Statement of problem: Restoring and replacing teeth with fixed prostheses commonly used in dental practice. Because of improper oral hygiene care and inaccurate laboratory procedure, complications of fixed prostheses were found in the mouth of patients. Although many efforts have been continually made to obtain the data of long term prognosis of fixed prostheses, it was difficult to do it. Purpose: The purpose of this study was to evaluate the clinical status of fixed prostheses. Material and methods: In order to assess the clinical status of fixed prostheses, a total of 161 individuals(aged 17-85, 99 women and 62 men with 1596 unit of fixed prostheses, and 1169 abutments) who first visited the Department of Prosthodontics, Pusan National University Hospital, between April to September, in 2007 were examined. Results and conclusion: The results of this study were as follows: 1. Length of service of fixed prostheses was $8.6{\pm}0.6$ years(mean), 10.0 years(median). 2. Location of fixed prostheses was found to have no statistically significant influence on longevity of fixed prostheses(P>.05). But, the success rate was high in posterior region and in mandible where the failure rate was high in combination(P<.05). 3. Longevity of fixed prostheses made of metal was longest(mean: $13.0{\pm}9.3$, median: 14.0), gold, precious ceramic, non-precious ceramic trailing behind(P<.05). 4. Number of units in fixed prostheses was found to have no statistically significant influence on longevity of fixed prostheses(P>.05). But, the success rate was high in Single-unit and the failure rate was high in over 3-unit(P<.05). 5. Condition of opposing dentition was found to have no statistically significant influence on longevity of fixed prostheses(P>.05). But, the success rate was high in natural dentition(P<.05). 6. Defective margin(28.2%), dental caries(23.0%), periodontal disease(19.3%), periapical disease(16.9%) were frequent complications. In 30.1% of the cases, abutment state after removing fixed prostheses was needed to be extracted.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.1
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• pp.48-54
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• 2010

Purpose: The objective of this study was to evaluate and compare the accuracy of impression body taking by the closed and the open tray impression technique with 3 types of impression tray. Individual tray, metal stock tray and polycarbonate tray were used. Materials and methods: Nine closed tray impressions were taken by individual tray, metal stock tray and polycarbonate stock tray, respectively with polyether impression material. 9 open tray impressions were also acquired by same manner. Precision analysis on the master models was performed by attaching the reference frameworks with alternate single screws and measuring the vertical fit discrepancy of respective analogues in working cast with a stereo microscope. Data were analyzed by 1 way ANOVA and independent t-test. Results: The average fit accuracy of impression bodies was calculated. With the closed tray impression technique, there were significant statistical differences in vertical fit discrepancy according to the types of tray. The individual tray group showed the lowest value and the polycarbonate stock tray group represented the highest. With the open tray impression technique, there was no significant difference in vertical fit discrepancy. Significant statistical difference in vertical fit discrepancy was found between the open and the closed impression technique with the polycarbonate stock tray. Conclusion: From the results above, more precise impressions could be acquired by the rigid individual tray compared with the polycarbonate stock tray. It was hard to get consistent accuracy impressions by the closed tray impression technique with polycarbonate stock trays.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.1
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• pp.1-7
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• 2016

Purpose: The aim of this study was to evaluate the effect of increased vertical dimension of occlusion on lower facial changes by facial type. Materials and methods: Lateral cephalograms from 261 patients were obtained and classified by sagittal (Class I, II, and III) and vertical (hypodivergent, normodivergent, and hyperdivergent) facial patterns. Retrusive displacement of soft tissue Pogonion and downward displacement of soft tissue Menton were measured in each group after 2 mm of vertical dimension of occlusion was increased at the lower central incisor using a virtual simulation program. The ratio of both displacements was calculated in all groups. The statistical analysis was done by 2-way ANOVA and Post hoc was done by Tukey test (5% level of significance). Results: Retrusive displacement of soft tissue Pogonion in Class III group was statistically different compared to Class I and II, and in vertical facial groups all 3 groups were significantly different (P<.05). Downward displacement of soft tissue Menton showed statistically significant difference between all sagittal groups and vertical groups (P<.05). The ratio of both displacements showed statistically significant difference in all sagittal groups and vertical groups (P<.05), and Class II hyperdivergent group had the highest value. Conclusion: Lower facial change was statically significant according to the facial type when vertical dimension of occlusion increased. Class II hyperdivergent facial type showed the highest ratio after increase in vertical dimension of occlusion.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.651-658
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• 2004

Runx2 is a transcription factor in homologous with Drosophila runt gene and it is essential for bone formation during embryogenesis and a critical gene for osteoblast differentiation and osteoblast function. Runx2-haploinsufficency causes cleidocranial dysplasia (CCD). CCD is an autosomal-dominant inherited disorder characterized by hypoplastic clevicle and delayed ossification in fontanelles and wormian bones. Dental defects are possibly shown to CCD patients : multiple supernumerary teeth, irregular and compressed permanent tooth crowns, hypoplastic and hypomineralized defects in enamel and dentin, an excess of epithelial root remnants, the absence of cellular cementum, and abnormally shaped roots. In addition, delayed eruption of the secondary dentition is a constant finding. The aim of this study is to evaluate the role of Runx2 in the tooth development and eruption through analyzing the expression pattern of Runx2 by in situ hybridization during crown (late bell stage) and root formation of tooth, using postnatal day 1, 4, 7, 14 and 21 mice mandibular molar teeth. mRNA of Runx2-full length is expressed in dental follicle and surrounding tissue at postnatal day1 and 4. At postnatal day 7, it is expressed in ameloblasts of occlusal surface of enamel and bone area surrounding the tooth. In comparison with previous stage, at postnatal day 14, it is expressed in ameloblasts of proximal surface of enamel. At postnatal day 21 it's expression is observed only in bone area. mRNA of Runx2-typeII is not expressed. At postnatal day 1 and 7. At postnatal day 14 and 21, it's expression is observed in the bone area. In this study, we suggest that Runx2 have a relation of ameloblasts differentiation and an important role to tooth eruption made by dental follicle during intraosseous eruption stage. Also we can confirm that Runx2 has a role to bone formation.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.337-349
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• 2008

Despite an improved bone reactions of Mg-incorporated implants in the animals, little yet has been carried out by the experimental investigations in functional loading conditions. This study investigated the clinical and histologic parameters of osseointegrated Mg-incorporated implants in delayed loading conditions. A total of 36 solid screw implants (diameter 3.75 mm, length 10mm) were placed in the mandibles of 6 beagle dogs. Test groups included 18 Mg-incorporated implants. Turned titanium Implants served as control. Gold crowns were inserted 3 months. Radiographic assessments and stabilitytests were performed at the time of fixture installation, $2^{nd}$ stage surgery, 1 and 3 months after loading. Histological observations and morphometrical measurements were also performed. Of 36 implants, 32 displayed no discernible mobility, corresponding to successful clinical function. There was no statistically significant difference between test implants and controls in marginal bone levels (p=0.413) and RFA values. The mean BIC % in the Mg-implants was $54.4{\pm}20.2%$. The mean BIC % in the turned implant was $48.9{\pm}8.0%$. These differences between the Mg-implant and control implant were not statistically significant (P=0.264). In the limitation of this study, bone-to-implant contact (BIC) and bone area of Mg-incorporated oxidized implant were similar to machine-turned implant. The stability analysis showed no significantly different ISQ values and marginal bone loss between two groups. Considering time-dependent bone responses of Mg-implant, it seems that Mg-implants enhanced bone responses in early loading conditions and osseointegrated similarly to cp Ti implants in delayed loading conditions. However, further investigations are necessary to obtain long-term bone response of the Mg-implant in human.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.2
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• pp.75-85
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• 2015

Purpose: The purpose of this study is to evaluate which FRC-posts were more distinguishable from core. Materials and Methods: Nine extracted single-rooted mandibular premolars with similar lengths (${\pm}0.5 mm$) and widths (${\pm}0.5 mm$) were endodontically treated and obturated. One specimen which the three roots were embedded in a cold mounting resin was made. 3 specimens were made by this method. Post spaces were prepared for the following post system: FRC $Postec^{(R)}$ Plus, MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$, $Snowpost^{(R)}$. After three different posts were placed in the roots of a specimen, each three specimens received a direct core build-up: $Luxacore^{(R)}$ Dual A3, $Luxacore^{(R)}$ Dual blue, $Filtek^{TM}$ Z350 A1E. Digital images were taken of the post and core with and without air-blowing. We asked to fifty dentists and fifty dental college students which post was more clearly discriminated from the core. Results: In surveys, when core was $Luxacore^{(R)}$ Dual blue, among three types of posts people more easily discriminated the $Snowpost^{(R)}$ from core. When core was $Luxacore^{(R)}$ Dual A3, among three types of posts people similarly more easily discriminated $Snowpost^{(R)}$ from core. When core was $Filtek^{TM}$ Z350 A1E, among three types of posts people more easily discriminated distinguished MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$ post from core. People more easily distinguished MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$ post from core when temperature was lowered by air-blowing. Conclusion: Ability to discriminate between FRC-post and core is different according to color contrast. MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$ posts are more discriminable when temperature is lowered by air-blowing.