• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.198-206
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• 2015

Purpose: We aimed to investigate the effect of combined various microgrooves and thermal oxidation on the titanium (Ti) and to evaluate various in vitro responses of human periodontal ligament cells (PLCs). Materials and methods: Grade II titanium disks were fabricated. Microgrooves were applied on titanium discs to have $0/0{{\mu}m}$, $15/3.5{{\mu}m}$, $30/10{{\mu}m}$, and $60/10{{\mu}m}$ of respective width/depth by photolithography. Thermal oxidation was performed on the microgrooves of Ti substrata for 3 h at $700^{\circ}C$ in air. The experiments were divided into 3 groups: control group (ST), thermal oxidation group (ST/TO), and combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO). Surface characterization was performed by field-emission scanning microscopy. Cell adhesion, osteoblastic differentiation, and mineralization were analyzed using the bromodeoxyurdine (BrdU), Alkaline phosphatase (ALP) activity, and extracellular calcium deposition assays, respectively. Statistical analysis was performed using the oneway analysis of variance and Pearson's bivariate correlation analysis (SPSS Version 17.0). Results: In general, the combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO) showed significantly higher levels compared with the control (ST) or thermal oxidation (ST-TO) groups in the BrdU expression, ALP activity, and extracellular calcium deposition. Gr60-TO group induced highest levels of cell adhesion and osteoblastic differentiation. Conclusion: Within the limitation of this study, we conclude that the Ti surface treatment using combined microgrooves and thermal oxidation is highly effective in inducing the cell adhesion andosteoblastic differentiation. The propose surface is also expected to be effective in inducing rapid and strong osseointegration of Ti oral implants.

• Journal of the Korean Arthroscopy Society
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• v.12 no.3
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• pp.198-204
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• 2008

Purpose: The purpose of this study is to analyze the merits and demerits of double bundle reconstruction and achieve improvements hereafter, by comparing the results of double bundle and single bundle reconstruction using tibialis anterior allograft. Materials and Methods: Twenty seven patients were divided to undergo either double bundle(n=14) or single bundle(n=13) reconstruction with tibialis anterior allograft tendon. The evaluation methods were AP laxity with KT-2000 arthrometer, isokinetic knee strength measurements, pivot-shift test, IKDC subjective score, Lysholm knee score, Tegner activity score, radiographic evaluations with postoperative MRI, and second look arthroscopy. Results: Lysholm knee score and Tegner activity score were significantly better in double bundle reconstruction. In pivot-shift test, single bundle reconstruction was evaluated as grade 0 in 10 of the knees, grade 1 in 1, and grade 2 in 2. Double bundle reconstruction was evaluated as grade 0 in 13, and grade 2 in 1. In second look arthroscopy, single bundle was evaluated as excellent in 6 of the knees, fair in 7, anteromedial bundle of double bundle reconstruction was excellent in 13 and fair in 1, and posterolateral bundle was excellent in 4, fair in 9, and poor in 1. There were no significant differences in other evaluations. Conclusion: Favorable outcome may be expected with double bundle reconstruction of ACL. However there are still need for improvement in terms of reconstruction technique and rehabilitation protocol to reduce PL bundle injury.

• Journal of the Korean Arthroscopy Society
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• v.15 no.2
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• pp.99-107
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• 2011

Purpose: The purpose of this study was to investigate the clinical results after a anatomical double bundle ACL reconstruction using a longitudinally split tibialis anterior allograft. Materials and Methods: We evaluated 24 patients with a minimum follow-up of 12 months who had undergone anatomical double bundle ACL reconstructions. The grafts utilized in all cases were tibialis anterior allografts which were longitudinally split into two strands. A standard rehabilitation protocol was applied in all patients. The pre- and post-operative data including Lysholm scores, International Knee Documentation Committee (IKDC) scores, Lachman test, pivot shift test and the side-to-side differences of anterior laxity measured by KT-2000 arthrometer were analyzed by use of a statistical method Results: The mean side-to-side instrumented laxity measured by the KT-2000 arthrometer significantly improved to a mean of $1.04{\pm}0.80\;mm$ (P < 0.001). The Lysholm knee scores also improved from $58.34{\pm}15.32$ to $86.25{\pm}6.48$ after surgery (P < 0.001). The patients exhibited improved IKDC scores (A: 15 cases, B; 9 cases) at the final follow-up, compared to preoperative scores (B: 5, C: 10, D: 9). Conclusion: Our data demonstrated that clinical results of anatomical double bundle ACL reconstruction with a split tibialis anterior allograft are encouraging with excellent side-to side laxity, significantly improved Lysholm knee score, IKDC score, Lachman and pivot shift data.

• Journal of the Korean Arthroscopy Society
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• v.11 no.2
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• pp.104-110
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• 2007

Purpose: The purpose of this study is comparison of clinical outcomes in ACL reconstruction between auto-hamstring tendon and allo-tibialis anterior tendon. Materials and Methods: In this prospective study, we included 60 subjects who underwent ACL reconstruction using 30 hamstring autograft(mainly, national health insurance) and 30 tibialis anterior allograft(including MVA and industrial injuries) between May 2003 and June 2005 by a single surgeon, with a minimum follow-up of 12 months. Outcome measurements were the range of motion, the Lachman test, the IKDC score, the Lysholm score, KT-1000 arthrometer and one-leg hop test. Results: For all the cases, the range of motion was above 135 degrees. The Lachman test, KT-1000 arthrometer and one-leg hop test showed no significant difference between two groups. The IKDC score of auto-hamstring group($87.840{\pm}2.106$) was significantly higher than that of allo-tibialis anterior group($85.273{\pm}2.782$). The Lysholm score of auto-hamstring group($88.067{\pm}2.586$) was also significantly higher than that of allo-tibialis anterior group($85.300{\pm}3.030$). Conclusion: The results of ACL reconstruction using the auto-hamstring tendon and allo-tibialis anterior tendon showed no significant difference in objective items but auto-hamstring group showed better results in subjective scoring. This difference may result from individual factors such as economic problem, secondary gain.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.625-630
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• 2009

Root resorption of primary teeth usually occurs as the succeeding permanent teeth erupt, which induces differentiation of the hemopoietic cells into osteoclasts. Their root resorption pattern reflects the eruption path of the succeeding permanent teeth, and eventually the primary teeth shed as their succeeding permanent teeth erupt. Even when a permanent tooth germ is congenitally missing, root resorption of the corresponding primary tooth may still occur due to various factors, such as inflammation, traumatic occlusal force, and weakness of periodontium etc. Such congenital missing of permanent teeth is a commonly observed phenomenon in human be ing, and it often accompanies delayed retention of primary teeth. The etiologic factors for congenital missing in elude not only systemic diseases, but also local factors and human evolution process. In the radiographs of the cases in this report, the primary teeth without succeeding permanent teeth show pathologic root resorption. Root resorption progressed about 1/2~3/4 of the roots, and the surfaces of the resorption area were irregular. Considering high susceptibility of the periodontal ligament of primary teeth to root resorption, pathologic root resorption of primary teeth with delayed retention can be explained by the increased masticatory muscle force and abnormal occlusion developed during the mixed dentition. When the primary teeth without succeeding permanent teeth are lost, decision for space maintenance is required and long-term treatment plan for further prosthetic or orthodontic treatment should be establsihed.

• Journal of the korean academy of Pediatric Dentistry
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• v.35 no.2
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• pp.205-215
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• 2008

The purpose of this study is to evaluate at which stage of tooth germ would develop into normal calcification and hence to increase the success rate of transplantation. Therefore, tooth germs on the 15th, 17th embryonic day and the 3rd day of birth were separated for allotransplantation into maxilla of adult rat of 11 weeks. Calcification processes were analyzed radiographically and histopathologically at 4 weeks and 8 weeks after allotransplantation. The results are as follows: 1. Allotransplanted tooth germ at 4 weeks and 8 weeks showed delayed calcification compared to that of normal odontogenesis. 2. At 4 weeks, abnormal calcified tissue, such as odontoma and ankylosis of osteodentin with surrounding alveolar bone were observed. 3. At 8 weeks, allotransplanted tooth germs of the 15th and 17th embryonic day showed calcification and osteodentin surrounded by periodontal ligament. 4. At 8 weeks, allotransplanted tooth germs of the 3rd day of birth showed calcification composed of cementum and osteodentin. In this study, we observed small sized and amorphous calcified tissue from allotropic allotransplantation of tooth germs. Since these calcified tissue were underdeveloped and shaped irregularly, for calcification into normal tooth form, further study needs consideration about the reduction of surgical trauma, developmental stage of transplanted tooth germ, blood supply from recipient site, fixation method in transplanted site and period of transplantation.

• Journal of the Korean Arthroscopy Society
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• v.7 no.2
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• pp.153-159
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• 2003

Purpose : The purpose of this study was to compare the pattern of displaced bucket-handle tear of lateral and medial menisci and the treatment modality and results from accompanying injury. Materials and Methods : Patients who were diagnosed for displaced bucket-handle tear of medial meniscus (group I: 52patients, 52cases) and lateral meniscus (group II: 31patients, 32cases) from September 1998 to December 2002. The mean ages were 25years $(16\~66)$ for Group I and 29years $(18\~63)$ for Group II, and the average follow-up period were 18months $(12\~44)$ and 13months $(6\~46)$, respectively. The zone of meniscus tear and the existence of accompanying injury were verified through intraoperative arthroscopy and discoid type meniscus was additionally examined for group II. The assessment was made according to the physical examination and clinical pattern at the postoperative last follow-up, and the 2nd look arthroscopy was performed in 19cases $(23\%)$ for the cases accompanying anterior cruciate ligament (ACL) injury in both groups. Results : There were 38cases $(73\%)$ in group I, 5cases $(16\%)$ in group II for associating ACL injury. We observed discoid type meniscus (19cases, $59\%$) in group II. At last follow-up clinical success in repair cases of group I and II are 22cases $(85\%)$, 2cases $(67\%)$, in resection cases are 26cases $(100\%)$, 26cases $(93\%)$ respectively. Reoperation is performed 2cases in repair cases of group I. One case is re-rupture, the other case is newly developed tear in white-white zone. Reoperation is performed 2cases due to remnant meniscal tear in resection cases of group II. All of 2cases are discoid type menisci. Conclusion : Displaced bucket-handle tear of medial & lateral menisci would be substantially different an aspect, considering on difference would help to select proper treatment modality.

• Journal of the Korean Arthroscopy Society
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• v.16 no.2
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• pp.128-133
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• 2012

Purpose: This study examined the relationship between graft appearance on follow-up magnetic resonance imaging (MRI) and knee stability after double bundle anterior cruciate ligament (ACL) reconstruction. Materials and Methods: For each patient, 1.5 tesla MRI's were obtained. The signal intensity of grafts was divided into 3 grades by Sononda's classification. The course of grafts was divided into two patterns: straight and curved. We assessed Lachman test, KT 2000 arthrometer and anterior drawer stress radiograph using Telos$^{(R)}$ in $30^{\circ}$ knee flexion for anterior stability and evaluated pivot shift test for rotatory stability. The correlation between graft appearance on MRI and the results of knee stability tests was evaluated. Results: The anteromedial (AM) graft was evaluated as being grade 1 in 66.7%, grade 2 in 26.7%, and grade 3 in 6.7% of the cases and the posterolateal (PL) graft was assessed as being grade 1 in 63.3%, grade 2 in 33.3%, and grade 3 in 3.3% of the cases according to the signal intensity. The AM graft was evaluated as being straight in 83.3% and curved in 16.7% of the cases, and the PL graft was assessed as being straight in 86.7% and curved in 13.3% of the cases according to the course. The course of AM graft was correlated with the results of anterior stability tests and the course of PL graft was correlated with the result of rotatory stability test. However, the signal intensity of grafts was not correlated with the results of anterior stability and rotatory stability tests. Conclusion: The course of AM is correlated with anterior stability and the course of PL is correlated with rotatory stability on follow-up MRI after double bundle ACL reconstruction.

• Journal of the Korean Arthroscopy Society
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• v.13 no.1
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• pp.8-13
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• 2009

Purpose: We used tibialis allograft for the reconstruction of ACL and used Hybrid femoral fixation utilizing $Endobutton^{(R)}$ and $Rigidfix^{(R)}$ for femoral fixation, and used $Retroscrew^{(R)}$ and additional fixation for tibial fixation to evaluate the clinical results. Materials and Methods: The ACL reconstruction were performed from February 2004 to February 2007 utilizing Hybrid femoral fixation and $Retroscrew^{(R)}$ and 32 patients, 32 cases which were available for year-long observation (12 to 25 months). The clinical results (Lysholm knee score, IKDC grade) and the radiologic results(bone tunnel expansion, Telos anterior displacement test) were evaluated. Results: The Lysholm knee score was improved from the average of $67.9{\pm}5.4$ points (range: 51~77) before operation and to $94.1{\pm}6.8$ points (range: 68~98) at the last follow up (p<0.05). 22 cases (69%) were evaluated normal (A), 9 cases (28%) were evaluated nearly normal (B) and only 1 case (3%) was evaluated not normal (C) at IKDC final evaluation and no case was evaluated abnormal. From $Telos^{(R)}$ stress x-ray evaluation, difference from the opposite knee was improved average 13.2 mm{\pm}5.8 (range: 6~21 mm) to average $3.4\;mm{\pm}2.8$ (range: 0~11 mm) after operation (p<0.05). The femoral and tibial tunnel were widened by 18.7% and 9.6% in the AP view and 12.4% and 8.5% in the lateral view, respectively (p<0.05). However, any statistic significance was not observed between bone tunnel expansion and knee joint functions (p>0.05). Conclusion: An ACL reconstruction with tibialis allograft using Hybrid femoral fixation and $Retroscrew^{(R)}$ enabled anatomical fixation of the graft tendon with satisfactory clinical results.

• The korean journal of orthodontics
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• v.33 no.4 s.99
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• pp.259-277
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• 2003

This study was designed to investigate the position of anteroposterior center of resistance for genuine intrusion and the mode of change of the minimum distal force for simultanous intrusion and retraction of the upper and lower incisors according to the increase of labial inclination. For this purpose, we used the three-piece intrusion arch appliance and three-dimensional finite element models of upper and lower incisors. 1. Positions of the center of resistance in upper incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 6m behind the distal surface of the lateral incisor bracket. 2) In $10^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 9mm behind the distal surface of the lateral incisor bracket. 3) In $20^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 12m behind the distal surface of the lateral incisor bracket. 4) In $30^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 16m behind the distal surface of the lateral incisor bracket. 2. Positions of the center of resistance in lower incisors according to the increase of the labial inclination were as follows; 1) In normal inclination situation, the center of resistance was located in 10mm behind the distal surface of the lateral incisor bracket. 2) In $10^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 13m behind the distal surface of the lateral incisor bracket. 3) In $20^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 15m behind the distal surface of the lateral incisor bracket. 4) In $30^{\circ}$ increase of the labial inclination situation, the center of resistance was located in 18m behind the distal surface of the lateral incisor bracket. 3. The patterns of stress distribution were as follows; 1) There were even compressive stresses In and periodontal ligament when intrusion force was applied through determined center of resistance. 2) There were gradual increase of complexity in compressive stress distribution pattern with Increase of the labial inclination when intrusion and retraction force were applied simultaneously. 4. With increase of the labial inclination of the upper and lower incisors, the position of the center of resistance moved posteriorly. And the distal force for pure intrusion was increased until $20^{\circ}$increase of the labial inclination.