Kang-Min Ahn - Academia.edu (original) (raw)

Papers by Kang-Min Ahn

Journal of the Korean Association of Oral and Maxillofacial Surgeons, 2016

To gain information on anatomical variation in anterolateral thigh (ALT) flaps in a series of cli... more To gain information on anatomical variation in anterolateral thigh (ALT) flaps in a series of clinical cases, with special focus on perforators and pedicles, for potential use in reconstruction of oral and maxillofacial soft tissue defects. Eight patients who underwent microvascular reconstructive surgery with ALT free flaps after ablative surgery for oral cancer were included. The number of perforators included in cutaneous flaps, location of perforators (septocutaneous or musculocutaneous), and the course of vascular pedicles were intraoperatively investigated. Four cases with a single perforator and four cases with multiple perforators were included in the ALT flap designed along the line from anterior superior iliac spine to patella. Three cases had perforators running the septum between the vastus lateralis and rectus femoris muscle (septocutaneous type), and five cases had perforators running in the vastus lateralis muscle (musculocutaneous type). Regarding the course of vascu...

Journal of International Society for Simulation Surgery, 2016

Maxillofacial Plastic and Reconstructive Surgery, 2016

Osteoradionecrosis is the most dreadful complication after head and neck irradiation. Orocutaneou... more Osteoradionecrosis is the most dreadful complication after head and neck irradiation. Orocutaneous fistula makes patients difficult to eat food. Fibular free flap is the choice of the flap for mandibular reconstruction. Osteocutaneous flap can reconstruct both hard and soft tissues simultaneously. This study was to investigate the success rate and results of the free fibular flap for osteoradionecrosis of the mandible and which side of the flap should be harvested for better reconstruction. A total of eight consecutive patients who underwent fibula reconstruction due to jaw necrosis from March 2008 to December 2015 were included in this study. Patients were classified according to stages, primary sites, radiation dose, survival, and quality of life. Five male and three female patients underwent operation. The mean age of the patients was 60.1 years old. Two male patients died of recurred disease of oral squamous cell carcinoma. The mean dose of radiation was 70.5 Gy. All fibular free flaps were survived. Five patients could eat normal diet after operation; however, three patients could eat only soft diet due to loss of teeth. Five patients reported no change of speech after operation, two reported worse speech ability, and one patient reported improved speech after operation. The ipsilateral side of the fibular flap was used when intraoral soft tissue defect with proximal side of the vascular pedicle is required. The contralateral side of the fibular flap was used when extraoral skin defect with proximal side of the vascular pedicle is required. Osteonecrosis of the jaw is hard to treat because of poor healing process and lack of vascularity. Free fibular flap is the choice of the surgery for jaw bone reconstruction and soft tissue fistula repair. The design and selection of the right or left fibular is dependent on the available vascular pedicle and soft tissue defect sites.

The journal of advanced prosthodontics, 2016

To evaluate the effects of hydrogen peroxide pretreatment and heat activation of silane on the sh... more To evaluate the effects of hydrogen peroxide pretreatment and heat activation of silane on the shear bond strength of fiber-reinforced composite posts to resin cement. The specimens were prepared to evaluate the bond strength of epoxy resin-based fiber posts (D.T. Light-Post) to dual-curing resin cement (RelyX U200). The specimens were divided into four groups (n=18) according to different surface treatments: group 1, no treatment; group 2, silanization; group 3, silanization after hydrogen peroxide etching; group 4, silanization with warm drying at 80℃ after hydrogen peroxide etching. After storage of the specimens in distilled water at 37℃ for 24 hours, the shear bond strength (in MPa) between the fiber post and resin cement was measured using a universal testing machine. The fractured surface of the fiber post was examined using scanning electron microscopy. Data were analyzed using one-way ANOVA and post-hoc analysis with Tukey's HSD test (α=0.05). Silanization of the fiber ...

Sensors and Actuators a Physical, Sep 1, 2007

This paper presents a compound nerve action potential (CNAP) monitoring system of a peripheral ne... more This paper presents a compound nerve action potential (CNAP) monitoring system of a peripheral nerve which is composed of a sieve-shape flexible microelectrode array (MEA), a polyglycolic acid (PGA) conduit and a bio-potential amplifier. The system observes a ...

Maxillofacial plastic and reconstructive surgery, 2016

Implant surgery has become popular with the advance of surgical techniques such as sinus lifting,... more Implant surgery has become popular with the advance of surgical techniques such as sinus lifting, guided bone regeneration, and block bone graft. However, there were no data about the frequency of bone graft during implant surgery. The purpose of this study was to report the frequency and types of bone graft depending on dental implant patients' profile to complement the database regarding implant surgery. The implant operations had been performed from January 2006 to October 2014. The upper and lower jaws were divided into six sextants. A total of 792 sextants were included in this study. Patient information including sex, age, sites, bone graft, and types of bone were investigated. A total of 1512 implants had been placed. Male and female sextants were 421 and 371, respectively (M:F = 1:0.88). Average age was 54.3 (ranging from 20 to 88 years old). Implants were placed in the posterior maxilla (322 sextants, 40.7 %), posterior mandible (286 sextants, 36.1 %), anterior maxilla ...

Journal of cranio-maxillo-facial surgery : official publication of the European Association for Cranio-Maxillo-Facial Surgery, Jan 2, 2016

Disadvantages of the radial forearm free flap (RFFF) are related to the forearm donor site, which... more Disadvantages of the radial forearm free flap (RFFF) are related to the forearm donor site, which requires skin grafting for closure. Due to that matter, an alternative technique using porcine collagen membrane instead of skin grafting was considered and evaluated for its efficacy of donor defect closure. Ten patients requiring reconstruction of oral & maxillofacial defect underwent the single-staged reconstruction with the RFFF. The flap was elevated and the porcine collagen membrane (Rapiderm(®)) was fixed at the donor site with tie-over dressing. After leaving it for at least 2 weeks, it was replaced with an iodine-coated furazine gauze for continuous healing. The patients did not develop any tendon exposure or infection. All forearms healed within 1 month. The mean graft size harvested was 27.75 ± 3.08 cm(2). A greater amount of granulation tissue was formed under the dressing gauze which resulted in a less conspicuous donor site. After 6 months the average scar dimension was 9....

Maxillofacial plastic and reconstructive surgery, 2015

Radial forearm free flap is the most reliable flap for intraoral soft tissue reconstruction after... more Radial forearm free flap is the most reliable flap for intraoral soft tissue reconstruction after cancer ablation surgery. However, unesthetic scar of the donor site and the need for a second donor site for skin graft are major disadvantages of the forearm flap. The purpose of this study was to report the clinical results of double-layered collagen graft to the donor site of the forearm free flap without skin graft. Twenty-two consecutive patients who underwent oral cancer ablation and forearm reconstruction between April 2010 and November 2013 were included in this study. Male to female ratio was 12:10, and average age was 61.0 years old (27-84). Double-layered collagen was grafted to the donor site of the forearm free flap and healed for secondary intention. Upper silicone had been trimmed at the periphery during secondary intention, and dry dressing was used. Postoperative scar healing and esthetic results and function were evaluated. An average follow-up period was 34.9 months. ...

Journal of Hard Tissue Biology, 2005

The endoscopic assisted approach for the treatment of condylar fracture is a less invasive altern... more The endoscopic assisted approach for the treatment of condylar fracture is a less invasive alternative treatment modality and is considered to be able to overcome the limited access to the operation field to obtain an accurate reduction and fixation. Six patients with condylar neck and ...

In vivo (Athens, Greece)

Recent studies have shown that matrix metalloproteinases (MMPs) from tumors influence the host im... more Recent studies have shown that matrix metalloproteinases (MMPs) from tumors influence the host immune system to reduce antitumor activity. The aim of this study was to examine the influence of MMP-2 and MMP-9 on the natural killer (NK) cell. NK cells were pretreated with either MMP-2 or MMP-9 in the experimental group but not in the control group. NK cell cytotoxicity against oral squamous cell carcinoma cells (OSCC) were examined using the [Cr51] release assay and the expression levels of surface receptors on NK cells were measured by flow cytometry. NK cell cytotoxicity was significantly reduced in the experimental group compared to the control group. Significant increases in KIR expression and decreases in NKG2D expression on the NK cells were observed in the experimental group. This study suggests an additional role of MMP-2 and MMP-9 in an immune escape mechanism of OSCC.

International journal of oral and maxillofacial surgery, 2004

Repair of long-span mandibular defects with a free fibular flap is now a routine procedure. Howev... more Repair of long-span mandibular defects with a free fibular flap is now a routine procedure. However, the bone height of the neo-mandible after reconstruction with a fibular flap is about half that of the dentulous mandible. When a fibular graft is placed only at the inferior border of the mandible, the resulting vertical discrepancy between the graft segment and the occlusal plane can adversely affect implant mechanics or denture stability and retention. To overcome these problems, we developed a technique for two-strut type mandibular reconstruction. A vascularized fibular segment is used to reconstruct the inferior basal portion of the neo-mandible, while a non-vascularized residual fibular segment is used to simulate the superior alveolar portion. We used this technique in 22 patients. Graft survival, graft resorption, and the ability to place implants were assessed as compared with those after the conventional one-strut type technique. The fibular segment grafted to the alveolar...

IEEE Transactions on Terahertz Science and Technology, 2013

We imaged a single case of oral malignant melanoma using terahertz (THz) reflection imaging at ro... more We imaged a single case of oral malignant melanoma using terahertz (THz) reflection imaging at room temperature (20 °C) and below freezing (-20 °C). A malignant nodule beneath the oral tissue surface was visualized using 2-D and B-scan THz imaging techniques. The THz images were well correlated with the histological findings. The nodule was found to have lower water content than that of normal cells, and this water effect may have influenced the THz refractive index and absorption coefficient at 20 °C. The THz spectroscopic image of the frozen tissue at -20 °C showed better contrast because of the lack of liquid water; this implies that there are significant structural differences between malignant oral melanoma cells and normal mucosal cells. The better contrast in the frozen tissue images was due to the greater penetration of THz radiation into the sample. This temperature-dependent THz imaging approach demonstrated the feasibility of accurate imaging of the oral tumor tissue.

Biomedical Optics Express, 2013

The feasibility of terahertz (THz) imaging at frozen temperature for the clinical application of ... more The feasibility of terahertz (THz) imaging at frozen temperature for the clinical application of oral cancer detection was investigated by analyzing seven oral tissues resected from four patients. The size, shape, and internal position of the oral cancers were mapped by THz radiation in the frequency range of 0.2-1.2 THz at 20 °C and 20 °C, and compared with those identified in the histological examination. THz imaging of frozen tissue was found to offer greater sensitivity in distinguishing cancerous areas from surrounding tissue and a larger THz-frequency spectral difference between the oral cancer and normal mucosa than roomtemperature THz imaging. A cancerous tumor hidden inside tissue was also detected using this method by observing the THz temporal domain waveform. The histological analysis showed that these findings resulted from cell structure deformations involving the invasion of oral tumor and neoplastic transformations of mucous cells. Therefore, a cytological approach using THz radiation at a frozen temperature might be applied to detect oral cancer.

$Research paper thumbnail of Full mouth rehabilitation on a bilateral condylar fractured patient using orthognathic surgery and dental implant$

The Journal of Advanced Prosthodontics, 2011

BACKGROUND. Mandibular displacement is a common complication of condylar fracture. In the mandibu... more BACKGROUND. Mandibular displacement is a common complication of condylar fracture. In the mandibular displacement due to condylar fracture, it is difficult to restore both esthetics and function without using orthognathic surgery. CASE DESCRIPTION. This clinical report described a full mouth rehabilitation in the patient with bilateral condylar fractures and displaced mandible using bilateral sagittal split ramus osteotomy (BSSRO) and simultaneous dental implant surgery. Mandibular position was determined by model surgery through the diagnostic wax up and restoration of fractured teeth. The precise amount of the mandibular shift can be obtained from the ideal intercuspation of remaining teeth. CLINICAL IMPLICATION. Mandibular displacement by both condylar fractures can be successfully treated by orthognathic surgery. Determination of occlusal plane and visualization from diagnostic wax up are mandatory for mandibular repositioning of model surgery. Stable occlusion and regular recall check up are needed for long-term outcome. [J Adv Prosthodont 2011;3:51-5] 51 CASE REPORT J Adv Prosthodont 2011;3:51-5

2007 IEEE Sensors, 2007

... Meth., vol. 73, pp. 177-186, may 1997. [6] Yong-Ho Kim, Chungkeun Lee, Kang Min Ahn, Yong-Jun... more ... Meth., vol. 73, pp. 177-186, may 1997. [6] Yong-Ho Kim, Chungkeun Lee, Kang Min Ahn, Yong-Jun Kim and Myoungho Lee, Function-inspection scheme for an injured peripheral nerve using a polymer based microelelctrode array, Sens. Actuator A-Phys., in press Fig. 10. ...

Journal of Clinical and Experimental Dentistry, 2010

Cholesterol granuloma is an inflammatory reaction to cholesterol crystals deposition. It may deve... more Cholesterol granuloma is an inflammatory reaction to cholesterol crystals deposition. It may develop in a variety of sites including the middle ear, mastoid process or even paranasal sinuses. Very few cases of cholesterol granuloma occurring in the jaws were reported. This report presents a rare case of cholesterol granuloma that developed in the wall of a large mandibular dentigerous cyst. The condition was treated with hemimandibulectomy followed by reconstruction with a free fibular flap.

Journal of Cranio-Maxillofacial Surgery, 2014

Cervical node metastasis of malignant ameloblastoma is extremely rare. Because of its rarity, the... more Cervical node metastasis of malignant ameloblastoma is extremely rare. Because of its rarity, there is no standard treatment modality in a single lymph node metastasis in malignant ameloblastoma. Eleven patients of malignant ameloblastoma involving a single cervical lymph node metastasis and one new case were reviewed. Neck treatment was classified into neck dissection and simple excision. Local nodal recurrence, distant metastasis and follow-up periods were investigated. Eight patients were treated with neck dissection (group A) and four patients underwent a simple node excision (group B). Two patients in group A experienced multiple organ metastases such as liver and lung seven months and 13 years after neck dissection respectively. The other patients showed no recurrence and metastasis. In group B, there was no report of a regional neck recurrence and distant metastasis during follow-up of 1-7 years. Multiple nodes metastasis requires a radical neck dissection; however, simple excision with close follow-up may be used in a single node metastasis in malignant ameloblastoma.

Sensors and Actuators A: Physical, 2007