Bok-Joo Kim

A comparative study of the effectiveness of sinus bone grafting with recombinant human bone morphogenetic protein 2–coated tricalcium phosphate and platelet-rich fibrin–mixed tricalcium phosphate in rabbits

OBJECTIVESnThe objective of this histologic study was to evaluate platelet-rich fibrin (PRF)-mixed tricalcium phosphate (TCP) and recombinant human bone morphogenic protein 2 (rhBMP-2)-coated TCP in their potential to enhance bone regeneration in sinus elevation in rabbits as well as in their inflammatory features.nnnSTUDY DESIGNnBilateral round-shaped defects (diameter 8.0 mm) were formed in the maxillary anterior sinus walls of 36 New Zealand white rabbits. The defects were grafted with TCP only (control group), with rhBMP-2-coated TCP (experimental group A) and with PRF-mixed TCP (experimental group B). Each group included 12 rabbits. The animals were killed at 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks, and 8 weeks. The specimens underwent decalcification and were stained for histologic analysis.nnnRESULTSnThere were no significant differences in inflammatory features among the groups at 3 days or the first week after operation. In a histomorphometric analysis, the new bone formation ratio showed significant differentiation between groups A and B. The TCP-only control group showed a relatively lower bone formation ratio rather than the experimental groups. The PRF-mixed TCP group showed a larger bone formation area, compared with both the control group and group A.nnnCONCLUSIONSnIn the results of the histologic evaluation (hematoxylin-eosin, Masson trichrome stain), the experimental groups A and B showed rapid bone formation, remodeling, and calcification in the second week. Moreover, there was a significant difference between those experimental groups and the control group in the new bone formation area at the fourth, sixth, and eighth weeks. The PRF-mixed TCP showed more rapid bone healing than the rhBMP-2-coated TCP or the TCP-only control.

The usefulness of cephalometric measurement as a diagnostic tool for obstructive sleep apnea syndrome: a retrospective study

OBJECTIVEnObstructive sleep apnea syndrome (OSAS) is a disorder characterized by apnea and hypopnea maintained for over 10xa0seconds and occurring at least 5 times per hour, with at least 30 episodes during 7xa0hours of nocturnal sleep. The most important pathophysiology in OSAS is the obstruction of the upper airway during sleep. The aim of this study was to identify the correlations between lateral cephalometric parameters, which seemed to be related to OSAS severities, and polysomnography (PSG) indices and to thus determine the cephalometric parameters reflecting OSAS severity.nnnPATIENTS AND METHODSnA total of 140 participants (122 males, 18 females) were evaluated by lateral cephalography and PSG. A total of 29 measurements (24 distances and 5 angles) were made on lateral cephalography. Cephalometric and PSG parameters were evaluated statistically to select and validate the cephalometric parameters reflecting OSAS severity.nnnRESULTnOSAS has a significant relationship with the anatomic deformities of craniofacial and soft tissues. Lateral cephalometry revealed that patients with OSAS have a significant vertical airway length, a regrognathic mandible, a thick uvula, a large tongue, and a long mid-face length. The position of the hyoid bone had a tendency to displace inferiorly and/or posteriorly. Using the discriminant variable combination, including tongue base-posterior nasal spine (T1-PNS), sella-nasion-B point angle (SNB), maximum uvula thickness (Max U), tongue base-tongue tip (T1-TT), and nasion-anterior nasal spine (N-ANS), 102 of 140 (72.9%) patients were correctly assigned to the normal-to-mild and moderate-to-severe apnea-hypopnea index (AHI) groups.nnnCONCLUSIONSnLateral cephalometric radiography may be an accessible and suitable tool for evaluation of craniofacial and soft tissue deformities in their correlations with OSAS severity. Further research on the cephalometric parameters reflecting OSAS severity is needed.

The role of kaempferol-induced autophagy on differentiation and mineralization of osteoblastic MC3T3-E1 cells

BackgroundKaempferol, a kind of flavonol, has been reported to possess various osteogenic biological activities, such as inhibiting bone resorption of osteoclasts and promoting the differentiation and mineralization of preosteoblasts. However, the precise cellular mechanism of action of kaempferol in osteogenesis is elusive.Autophagy is a major intracellular degradation system, which plays an important role in cell growth, survival, differentiation and homeostasis in mammals. Recent studies showed that autophagy appeared to be involved in the degradation of osteoclasts, osteoblasts and osteocytes, potentially pointing to a new pathogenic mechanism of bone homeostasis and bone marrow disease. The potential correlation between autophagy, osteogenesis and flavonoids is unclear.MethodsThe present study verified that kaempferol promoted osteogenic differentiation and mineralization and that it elevated osteogenic gene expression based on alkaline phosphatase (ALP) activity, alizarin red staining and quantitative PCR. And then we found that kaempferol induced autophagy by acridine orange (AO) and monodansylcadaverine (MDC) staining and autophagy-related protein expression. The correlation between kaempferol-induced autophagy and the osteogenic process was confirmed by the autophagy inhibitor 3-methyladenine (3-MA).ResultsKaempferol promoted the proliferation, differentiation and mineralization of osteoblasts at a concentration of 10xa0μM. Kaempferol showed cytotoxic properties at concentrations above 50xa0μM. Concentrations above 10xa0μM decreased ALP activity, whereas those up to 10xa0μM increased ALP activity. Kaempferol at concentrations up to 10xa0μM also increased the expression of the osteoblast- activated factors RUNX-2, osterix, BMP-2 and collagen I according to RT-PCR analyses. 10xa0μM or less, the higher of the concentration and over time, kaempferol promoted the activity of osteoblasts. Kaempferol induced autophagy. It also increased the expression of the autophagy-related factors beclin-1, SQSTM1/p62 and the conversion of LC3-II from LC3-I. The application of 3-MA decreased the activity of ALP and the autophagy induced by kaempferol. In the RT-PCR analysis, the expression of RUNX-2, osterix, BMP-2 and collagen I was decreased.ConclusionThe present study showed that kaempferol stimulated the osteogenic differentiation of cultured osteoblasts by inducing autophagy.

Effect of simultaneous therapy of arthrocentesis and occlusal splints on temporomandibular disorders: anterior disc displacement without reduction

Objectives This study sought to evaluate the effect of simultaneous application of arthrocentesis and occlusal splint. Materials and Methods A retrospective study of 43 patients (3 males, 40 females) whose symptoms had improved was conducted at the Department of Oral and Maxillofacial Surgery, Dong-A University Hospital between 2008 and 2010. Subjects were divided into three groups: Group A (17 patients with arthrocentesis and occlusal splints simultaneously applied), Group B (13 patients whose symptoms did not improve with occlusal splints, undergoing arthrocentesis after occlusal splint use for 8 weeks), and Group C (13 patients that only used occlusal splints). We compared these groups in maximum comfortable opening (MCO) and the visual analogue scale of pain and noise. Follow-up was performed at 1 week, 1 month, 3 months, and 6 months. Results The improvement of symptoms was noted in all three groups, but Group A had a quicker improvement than the other groups, in terms of pain reduction and MCO increases. Conclusion The simultaneous application of arthrocentesis and occlusal splints can reduce patient discomfort more quickly.

Facial asymmetry: a case report of localized linear scleroderma patient with muscular strain and spasm

Facial asymmetry is found in patients with or without cosmetic facial alterations. Some patients have facial asymmetry that manifests underlying skeletal problems, while others have only limited soft-tissue facial asymmetry. Orthognathic surgery brings about a dermatic change, as soft tissue covers underlying bones. Limited soft-tissue asymmetry, meanwhile, is difficult to correct. The treatment modalities for the creation or restoration of an esthetically pleasing appearance were autogenous fat grafts, cartilage graft, and silicon injections.A young female patient had right-side facial asymmetry. The clinical assessment involved visual inspection of the face and palpation to differentiate soft tissue and bone. Although the extra-oral examination found facial asymmetry with skin atrophy, the radiographic findings revealed no mandibular atrophy or deviation. She was diagnosed as localized scleroderma with muscle spasm.In conclusion, facial asymmetry patients with skeletal asymmetry can be esthetically satisfied by orthognathic surgery; however, facial atrophy patients with skin or subdermal tissue contraction need treatment by cosmetic dermatological surgery and orthodontic correction.

Complication rates in patients using absorbable collagen sponges in third molar extraction sockets: a retrospective study.

Objectives The purpose of this study is to retrospectively evaluate the postoperative complication rates for absorbable type-I collagen sponge (Ateloplug; Bioland) use in third molar extraction. Materials and Methods From January to August 2013, 2,697 total patients undergoing third molar extraction and type-I collagen sponge application in the Department of Oral and Maxillofacial Surgery at Yonsei University Dental Hospital (1,163 patients) and Dong-A University Hospital (1,534 patients) were evaluated in a retrospective study using their operation and medical records. Results A total of 3,869 third molars in 2,697 patients were extracted and the extraction sockets packed with type-I collagen sponges to prevent postoperative complications. As a result, the overall complication rate was 4.52%, with 3.00% experiencing surgical site infection (SSI), 1.14% showing alveolar osteitis, and 0.39% experiencing hematoma. Of the total number of complications, SSI accounted for more than a half at 66.29%. Conclusion Compared to previous studies, this study showed a relatively low incidence of complications. The use of type-I collagen sponges is recommended for the prevention of complications after third molar extraction.

Reconstruction of extensive jaw defects induced by keratocystic odontogenic tumor via patient-customized devices

Keratocystic odontogenic tumors can occur in any area of the maxilla or mandible. According to their size, location, and relations with surrounding structures, they are treated by cyst enucleation or enucleation after either marsupialization or decompression. Enucleation is performed when cysts are not large and when only minor damage to adjacent anatomical structures is expected. Although marsupialization and decompression follow the same basic bone-regeneration principle, which is to say, by reducing the pressure within the cyst, the former leaves a large defect after healing due to the large fistula necessary to induce the conversion of the cyst-lining epithelia to oral epithelia; the latter leaves only a relatively small defect, because of the continuous washing carried out by means of a tube inserted into a small hole in the cyst. In the latter case too, a decompressor appropriate for the focal position is required, owing to the importance of maintaining the device and controlling for oral hygiene. We report herein decompression treatment with a patient-customized device for an extensive cyst in the anterior region of the mandible.

Cytoprotective effect of flavonoid-induced autophagy on bisphosphonate mediated cell death in osteoblast

With rapid economic growth and further developments in medical science, the entry into the aging population is currently increasing, as is the number of patients with metabolic diseases, such as hypertension, hyperlipidemia, heart disease, and diabetes. The current treatments for metabolic bone diseases, which are also on the rise, cause negative side effects. Bisphosphonates, which are used to treat osteoporosis, inhibit the bone resorption ability of osteoclasts and during prolonged administration, cause bisphosphonate‐related osteonecrosis of the jaw (BRONJ). Numerous studies have shown the potential role of natural plant products as flavonoids in the protection against osteoporosis and in the influence of bone remodeling. Autophagy occurs after the degradation of cytoplasmic components within the lysosome and serves as an essential cytoprotective response to pathologic stress caused by certain diseases. In the present study, we hypothesized that the cytoprotective effects of flavonoids might be related to those associated with autophagy, an essential cytoprotective response to the pathologic stress caused by certain diseases, in osteoblasts. We demonstrated the cytoprotective effect of flavonoid‐induced autophagy against the toxicity of zoledronate and the induction of autophagy by flavonoids to support osteogenic transcription factors, leading to osteoblast differentiation and bone formation. Further studies are necessary to clarify the connections between autophagy and osteogenesis. It would be helpful to shed light on methodological challenges through molecular biological studies and new animal models. The findings of the current study may help to delineate the potential role of flavonoids in the treatment of metabolic bone disease.

The Effects of Kaempferol-Inhibited Autophagy on Osteoclast Formation

Kaempferol, a flavonoid compound, is derived from the rhizome of Kaempferia galanga L., which is used in traditional medicine in Asia. Autophagy has pleiotropic functions that are involved in cell growth, survival, nutrient supply under starvation, defense against pathogens, and antigen presentation. There are many studies dealing with the inhibitory effects of natural flavonoids in bone resorption. However, no studies have explained the relationship between the autophagic and inhibitory processes of osteoclastogenesis by natural flavonoids. The present study was undertaken to investigate the inhibitory effects of osteoclastogenesis through the autophagy inhibition process stimulated by kaempferol in murin macrophage (RAW 264.7) cells. The cytotoxic effect of Kaempferol was investigated by MTT assay. The osteoclast differentiation and autophagic process were confirmed via tartrate-resistant acid phosphatase (TRAP) staining, pit formation assay, western blot, and real-time PCR. Kaempferol controlled the expression of autophagy-related factors and in particular, it strongly inhibited the expression of p62/SQSTM1. In the western blot and real time-PCR analysis, when autophagy was suppressed with the application of 3-Methyladenine (3-MA) only, osteoclast and apoptosis related factors were not significantly affected. However, we found that after cells were treated with kaempferol, these factors inhibited autophagy and activated apoptosis. Therefore, we presume that kaempferol-inhibited autophagy activated apoptosis by degradation of p62/SQSTM1. Further study of the p62/SQSTM1 gene as a target in the autophagy mechanism, may help to delineate the potential role of kaempferol in the treatment of bone metabolism disorders.

Lateral approach for maxillary sinus membrane elevation without bone materials in maxillary mucous retention cyst with immediate or delayed implant rehabilitation: case reports

This case series study demonstrates the possibility of successful implant rehabilitation without bone augmentation in the atrophic posterior maxilla with cystic lesion in the sinus. Sinus lift without bone graft using the lateral approach was performed. In one patient, the cyst was aspirated and simultaneous implantation under local anesthesia was performed, whereas the other cyst was removed under general anesthesia, and the sinus membrane was elevated in a second process, followed by implantation. In both cases, tapered 11.5-mm-long implants were utilized. With all of the implants, good stability and appropriate bone height were achieved. The mean bone level gain was 5.73 mm; adequate bone augmentation around the implants was shown, the sinus floor was moved apically, and the cyst was no longer radiologically detected. Completion of all of the treatments required an average of 12.5 months. The present study showed that sufficient bone formation and stable implantation in a maxilla of insufficient bone volume are possible through sinus lift without bone materials. The results serve to demonstrate, moreover, that surgical treatment of mucous retention cyst can facilitate rehabilitation. These techniques can reduce the risk of complications related to bone grafts, save money, and successfully treat antral cyst.