Polydeoxyribonucleotide, as a Novel Approach for the Management of Medication-Related Osteonecrosis of the Jaw: A Preliminary Observational Study

PURPOSE: Polydeoxyribonucleotide (PDRN), consisting of a mixture of deoxyribonucleotide polymers, has been suggested to have anti-inflammatory effects and enhance angiogenesis as an adenosine A(2A) receptor agonist. The aim of this study was to report the effectiveness of PDRN as an adjuvant therapy after surgical debridement in MRONJ (medication-related osteonecrosis of the jaw) patients. MATERIALS AND METHODS: Five patients (1 male, 4 females, age 65~79 years) who were diagnosed with MRONJ stage 2 or 3 underwent surgical debridement and PDRN mucosal injection. After surgical debridement, patients were subject to daily injection with 1 ml of PDRN around the surgical wound for 14 days. RESULT: The patients' symptoms gradually disappeared. The surgical wound uneventfully healed, and no recurrence was observed during the follow-up period. CONCLUSION: Although further studies are required, the present study first describes the possibility of PDRN as a useful option for MRONJ treatment.

Surgical Treatment for a Huge Maxillary Ameloblastoma via Le Fort I Osteotomy: A Case Report

Ameloblastomaa are odontogenic benign tumors with epithelial origin, which are characterized by slow, aggressive, and invasive growth. Most ameloblastomas occur in the mandible, and their prevalence in the maxilla is low. A 27-year-old male visited our clinic with a chief complaint of the left side nasal airway obstruction. Three-dimensional computed tomography showed left maxillary sinus filled with a mass. Except for the perforated maxillary left edentulous area, no invaded or destructed bone was noted. The tumor was excised via Le Fort I osteotomy. The main mass was then sent for biopsy and it revealed acanthomatous ameloblastoma. The lesion in the left maxillary sinus reached the ethmoidal sinus through the nasal cavity but did not invade the orbit and skull base. The tumor was accessed through a Le Fort I downfracture in consideration of the growth pattern and range of invasion. The operation site healed without aesthetic appearances and functional impairments. However, further long-term clinical observation is necessary in the future for the recurrence of ameloblastoma. Conservative surgical treatment could be the first choice considering fast recovery after surgery and the patient's life quality.

Midfacial degloving approach for management of the maxillary fibrous dysplasia: a case report / 대한악안면성형재건외과학회지

BACKGROUND: Fibrous dysplasia (FD) is a benign bone lesion characterized by the progressive replacement of normal bone with fibro-osseous connective tissue. The maxilla is the most commonly affected area of facial bone, resulting in facial asymmetry and functional disorders. Surgery is an effective management option and involves removing the diseased bone via an intraoral approach: conservative bone shaving or radical excision and reconstruction. CASE PRESENTATION: This case report describes a monostotic fibrous dysplasia in which the patient’s right midface had a prominent appearance. The asymmetric maxillary area was surgically recontoured via the midfacial degloving approach under general anesthesia. Follow-up photography and radiographic imaging after surgery showed the structures were in a stable state without recurrence of the FD lesion. Furthermore, there were no visible scars or functional disability, and the patient reported no postoperative discomfort. CONCLUSIONS: In conclusion, the midfacial degloving approach for treatment of maxillary fibrous dysplasia is a reliable and successful treatment option. Without visible scars and virtually free of postoperative functional disability, this approach offers good exposure of the middle third of the face for treatment of maxillary fibrous dysplasia with excellent cosmetic outcomes.

Conservative surgical treatment for ameloblastoma: a report of three cases

Ameloblastoma treatment varies based on the clinical, histopathologic, and radiographic characteristics. Aggressive surgical treatments, such as marginal or segmental resection, have traditionally been implemented, but some conservative surgical methods are also being introduced, including decompression, enucleation, or curettage. The aim of the present study was to evaluate the possibility of applying these conservative surgical treatments to ameloblastoma and to analyze the prognosis of the procedures and their healing aspects. Among all patients who visited our clinic (Department of Oral and Maxillofacial Surgery, Kyung Hee University Dental Hospital at Gangdong) from 2009 to 2017, three who had undergone conservative surgery were recruited. One of these three patients underwent both excision of the lesion and an iliac bone graft during the same procedure. In the other two patients, due to the size of the lesion, decompression was performed to reduce the size of the lesion, and then conservative surgical treatments followed. As shown in the cases of this study, patients were only treated with conservative surgical methods, such as decompression or enucleation. During the follow-up period, there were no recurrences. In conclusion, the use of conservative surgical treatment in ameloblastoma can be a reliable, safe, and successful method.

Application of Monitored Anesthesia Care Using Dexmedetomidine to Common Oral and Maxillofacial Trauma Cases

Oral and maxillofacial surgery (OMFS) trauma cases are commonly treated under general anesthesia. The purpose of this case report is to introduce an alternative method of anesthesia in patients who refuse general anesthesia. A combination of dexmedetomidine and ketamine for sedation anesthesia in 3 frequent fracture types in the field of OMFS—Le Fort I fracture, mandibular fracture, and alveolar bone fracture—was used. Dexmedetomidine as the single agent has not shown stable success rates for invasive procedures. To overcome some of the pitfalls with dexmedetomidine, combination sedation using ketamine was performed. Visual analogue scale scores were recorded postoperatively. Dexmedetomidine combined with ketamine administration provided safe and effective sedation and anxiolysis for surgical reduction and internal fixation of OMFS fractures. It showed advantages of decreased admission time, reduced expenses, minimal pain, and reduced anesthetic burden for the patient thus ultimately increasing overall satisfaction.

Dexmedetomidine Oral Mucosa Patch for Sedation Suppresses Apoptosis in Hippocampus of Normal Rats / 대한배뇨장애요실금학회지

PURPOSE: Dexmedetomidine, an α2-adrenergic agonist, provides sedative and analgesic effects without significant respiratory depression. Dexmedetomidine has been suggested to have an antiapoptotic effect in response to various brain insults. We developed an oral mucosa patch using dexmedetomidine for sedation. The effects of the dexmedetomidine oral mucosa patch on cell proliferation and apoptosis in the hippocampus were evaluated. METHODS: A hydrogel oral mucosa patch was adhered onto the oral cavity of physiologically normal rats, and was attached for 2 hours, 6 hours, 12 hours, or 24 hours. Plasma dexmedetomidine concentrations were determined by liquid chromatography– electrospray ionization–tandem mass spectrometry–multiple-ion reaction monitoring (LC-ESI-MS/MS-MRM). Cell proliferation in the hippocampus was detected by Ki-67 immunohistochemistry. Caspase-3 immunohistochemistry, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining, and Western blotting for Bax and Bcl-2 were performed to detect hippocampal apoptosis. The levels of brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) in the hippocampus were also measured by Western blotting. RESULTS: Plasma dexmedetomidine concentration increased according to the attachment time of the dexmedetomidine oral mucosa patch. Hippocampal cell proliferation did not change due to the dexmedetomidine oral mucosa patch, and the dexmedetomidine oral mucosa patch exerted no significant effect on BDNF or TrkB expression. In contrast, the dexmedetomidine oral mucosa patch exerted an antiapoptotic effect depending on the attachment time of the dexmedetomidine oral mucosa patch. CONCLUSIONS: A dexmedetomidine oral mucosa patch can be used as a convenient tool for sedation, and is of therapeutic value due to its antiapoptotic effects under normal conditions.

Study on the trends in Korean clinical practice guidelines development

BACKGROUND: The definition of evidence-based clinical practice guidelines (CPGs) is "statements that are systematically developed to assist in the doctors' and patients' decision-making in certain situations." This study aims to establish the concept of evidence-based CPGs and investigate the development status to seek measures to apply evidence-based methods to CPG development for dental sedation in Korea. METHODS: The study conducted systematic searching methods based on evidence-based CPGs. Articles published between 1995 to 2015 were searched on a Korean database and the international database PubMed. The search was based on keywords related to four subjects (dentistry, clinical practice, guideline, recommendation). Two authors independently reviewed the searched articles to determine their analysis inclusion and the convergence stages, and to arrive at a conclusion through discussion. RESULTS: A total of 65 Korean CPGs were included. There were 51 medical guidelines, of which seven were dental and seven were Oriental medicine. CONCLUSIONS: As a basic direction for the development of evidence-based CPGs, this work suggests the following: increased awareness; consensus on the need to supply evidence-based development methods; education, computerization, and systematic observation of evidence-based CPG development methods; continuous research development and distribution of CPGs; and creation of a database for Korean clinical dentistry practice outcomes.

Bone Regeneration in the Extraction Socket Filled with Atelocollagen: Histological and Radiographic Study in Beagle Dogs

PURPOSE: Alveolar bone develops with tooth eruption and is absorbed following tooth extraction. Various ridge preservation techniques have sought to prevent ridge atrophy, with no superior technique evident. Collagen has a long history as a biocompatible material. Its usefulness and safety have been amply verified. The related compound, atelocollagen, is also safe and displays reduced antigenicity since telopeptides are not present. MATERIALS AND METHODS: The current study evaluated whether the Rapiderm® atelocollagen plug (Dalim Tissen, Seoul, Korea) improves tissue healing of extraction sockets and assessed the sequential pattern of bone regeneration using histology and microcomputed tomography in six beagle dogs. To assess the change of extraction socket, hard tissues were examined 2, 4, 6, and 8 weeks after tooth extraction. RESULT: The experimental groups showed better bone fill with slow remodeling process compared to the control groups although there was no statistical difference between groups. CONCLUSION: The atelocollagen seems to have a tendency to slow bone remodeling in the early phase of healing period and maintain remodeling capacity until late phase of remodeling. Also, use of atelocollagen increased the bone-to-tissue ratio compared to healing of untreated extraction socket.

Developmental procedures for the clinical practice guidelines for conscious sedation in dentistry for the Korean Academy of Dental Sciences

BACKGROUND: Evidence-based clinical practice guidelines (CPGs) are defined as “statements that are scientifically reviewed about evidence and systematically developed to assist in the doctors' and patients' decision making in certain clinical situations.” This recommendation aims to promote good clinical practice for the provision of safe and effective practices of conscious sedation in dentistry. METHODS: The development of this clinical practice guideline was conducted by performing a systematic search of the literature for evidence-based CPGs. Existing guidelines, relevant systematic reviews, policy documents, legislation, or other recommendations were reviewed and appraised. To supplement this information, key questions were formulated by the Guideline Development Group and used as the basis for designing systematic literature search strategies to identify literature that may address these questions. Guideline documents were evaluated through a review of domestic and international databases for the development of a renewing of existing conscious sedation guidelines for dentistry. Clinical practice guidelines were critically appraised for their methodologies using Appraisal of guidelines for research and evaluation (AGREE) II. RESULTS: A total of 12 existing CPGs were included and 13 recommendations were made in a range of general, adult, and pediatric areas. CONCLUSION: The clinical practice guidelines for conscious sedation will be reviewed in 5 years' time for further updates to reflect significant changes in the field.

The alternative of oral sedation for pediatric dental care

In pediatric dentistry, chloral hydrate is habitually selected for sedation of uncooperative children. Although chloral hydrate has been used for decades, various adverse effects are reported and necessity for new alternative drugs has increased. Dexmedetomidine was approved by FDA for sedation at intensive care units (ICU) in 1999. Compared to conventional sedative drugs, dexmedetomidine has not only analgesic and sedative effects but also it barely suppresses the respiratory system. Due to these characteristics, dexmedetomidine is known as safe sedative drug for children and elderly patients. Furthermore, approved by KFDA in 2010 in Korea, the frequency of sedation using dexmedetomidine is increasing. However, due to its intravenous administration method, it was difficult to apply in pediatric dentistry. Recently, intranasal administration method was introduced which might be a new possible alternative of oral sedation. In this study, we compare the mechanisms, pros and cons of chloral hydrate and dexmedetomidine, introducing new possibilities.

Analyses Using Micro-CT Scans and Tissue Staining on New Bone Formation and Bone Fusion According to the Timing of Cranioplasty via Frozen Autologous Bone Flaps in Rabbits : A Preliminary Report

OBJECTIVE: The timing of cranioplasty and method of bone flap storage are known risk factors of non-union and resorption of bone flaps. In this animal experimental study, we evaluated the efficacy of cranioplasty using frozen autologous bone flap, and examined whether the timing of cranioplasty after craniectomy affects bone fusion and new bone formation. METHODS: Total 8 rabbits (male, older than 16 weeks) were divided into two groups of early cranioplasty group (EG, 4 rabbits) and delayed cranioplasty group (DG, 4 rabbits). The rabbits of each group were performed cranioplasty via frozen autologous bone flaps 4 weeks (EG) and 8 weeks (DG) after craniectomy. In order to obtain control data, the cranioplasty immediate after craniectomy were made on the contralateral cranial bone of the rabbits (control group, CG).The bone fusion and new bone formation were evaluated by micro-CT scan and histological examination 8 weeks after cranioplasty on both groups. RESULTS: In the micro-CT scans, the mean values of the volume and the surface of new bone were 50.13+/-7.18 mm3 and 706.23+/-77.26 mm2 in EG, 53.78+/-10.86 mm3 and 726.60+/-170.99 mm2 in DG, and 31.51+/-12.84 mm3 and 436.65+/-132.24 mm2 in CG. In the statistical results, significant differences were shown between EG and CG and between DG and CG (volume : p=0.028 and surface : p=0.008). The histological results confirmed new bone formation in all rabbits. CONCLUSION: We observed new bone formation on all the frozen autologous bone flaps that was stored within 8 weeks. The timing of cranioplasty may showed no difference of degree of new bone formation. Not only the healing period after cranioplasty but the time interval from craniectomy to cranioplasty could affect the new bone formation.

Magnesium vs. machined surfaced titanium - osteoblast and osteoclast differentiation

PURPOSE: This study focused on in vitro cell differentiation and surface characteristics in a magnesium coated titanium surface implanted on using a plasma ion source. MATERIALS AND METHODS: 40 commercially made pure titanium discs were prepared to produce Ti oxide machined surface (M) and Mg-incorporated Ti oxide machined surface (MM). Surface properties were analyzed using a scanning electron microscopy (SEM). On each surface, alkaline phosphatase (ALP) activity, alizarin red S staining for mineralization of MC3T3-E1 cells, and quantitative analysis of osteoblastic gene expression, were evaluated. Actin ring formation assay and gene expression analysis of TRAP and GAPDH performing RT-PCR were performed to characterize osteoclast differentiation on mouse bone marrow-derived macrophages (BMMs). RESULTS: MM showed similar surface morphology and surface roughness with M, but was slightly smoother after ion implantation at the micron scale. M was more hydrophobic than MM. No significant difference between surfaces on ALP activity at 7 and 14 days were observed. Real-time PCR analyses showed similar levels of mRNA expression of the osteoblast phenotype genes; osteopontin (OPN), osteocalcin (OCN), bone sialoprotein (BSP), and collagen 1 (Col 1) in cell grown on MM at 7, 14 and 21 days. Alizarin red S staining at 21 days showed no significant difference. BMMs differentiation increased in M and MM. Actin ring formation assay and gene expression analysis of TRAP showed osteoclast differentiation to be more active on MM. CONCLUSION: Both M and MM have a good effect on osteoblastic cell differentiation, but MM may speed the bone remodeling process by activating on osteoclast differentiation.

Mouthguard use in Korean Taekwondo athletes - awareness and attitude

PURPOSE: A survey was performed to identify the level of mouthguard use, awareness, wearability issues and attitude toward mouthguard among elite Korean Taewondo athletes. MATERIALS AND METHODS: Survey questionnaires were given to 152 athletes participating in the Korea National Taekwondo team selection event for the 2010 Guangzhou Asian Games. Questionnaires consisted of three sections, mouthguard awareness, reasons for not wearing mouthguard and the last section to test the level of acceptance on current mouthguard and when the identified problems were resolved. For analyzing difference among response, chi2 test was used and significant level (alpha) was set up as 0.05. RESULTS: Responses in each of items showed significant difference (P<.001). Majority of response regarding each question: Majority of respondents believed that mouthguard were effective in preventing injuries (36.4%) but the result suggested that the provision of information on mouthguard to athletes was inadequate (44.0%) and the result showed that respondents were not greatly interested or concerned in relation to the mandatory mouthguard rule (31.6%). Although the responses on the level of comfort and wearability of mouthguard were negative (34.8%), athletes were positively willing to wear mouthguard if the problems rectified (51.2%). CONCLUSION: Considering the high level of willingness to wear mouthguard if the problems rectified, it is thought that together with efforts in providing more mouthguard information, the work of sports dentistry to research and improve mouthguard will be invaluable in promoting mouthguard to more athletes.

A Case Report of Temporomandibular Bilateral Osseous Ankylosis Treated by Total Joint Replacement in Ankylosing Spondylitis

Polymorphous Low-grade Adenocarcinoma of the Palate: Case Report

Bone regeneration effects of human allogenous bone substitutes: a preliminary study

PURPOSE: The purpose of this study was to compare the bone regeneration effects of cortical, cancellous, and cortico-cancellous human bone substitutes on calvarial defects of rabbits. METHODS: Four 8-mm diameter calvarial defects were created in each of nine New Zealand white rabbits. Freeze-dried cortical bone, freeze-dried cortico-cancellous bone, and demineralized bone matrix with freeze-dried cancellous bone were inserted into the defects, while the non-grafted defect was regarded as the control. After 4, 8, and 12 weeks of healing, the experimental animals were euthanized for specimen preparation. Micro-computed tomography (micro-CT) was performed to calculate the percent bone volume. After histological evaluation, histomorphometric analysis was performed to quantify new bone formation. RESULTS: In micro-CT evaluation, freeze-dried cortico-cancellous human bone showed the highest percent bone volume value among the experimental groups at week 4. At week 8 and week 12, freeze-dried cortical human bone showed the highest percent bone volume value among the experimental groups. In histologic evaluation, at week 4, freeze-dried cortico-cancellous human bone showed more prominent osteoid tissue than any other group. New bone formation was increased in all of the experimental groups at week 8 and 12. Histomorphometric data showed that freeze-dried cortico-cancellous human bone showed a significantly higher new bone formation percentile value than any other experimental group at week 4. At week 8, freeze-dried cortical human bone showed the highest value, of which a significant difference existed between freeze-dried cortical human bone and demineralized bone matrix with freeze-dried cancellous human bone. At week 12, there were no significant differences among the experimental groups. CONCLUSIONS: Freeze-dried cortico-cancellous human bone showed swift new bone formation at the 4-week healing phase, whereas there was less difference in new bone formation among the experimental groups in the following healing phases.

Mediastinitis: a case report

Acute mediastinitis is a fatal infection which occurs related to connective tissue of mediastium, in the thoratic organs. Occurrence of mediastinitis due to craniocervical infection is very rare, and is defined as descending necrotizing mediastinitis. November 8th, 2008, man in his early fifties visited ER due to severe swelling on left neck area and dyspnea. Antibiotic were administered immediately, and vast amount of abscess formation on pneumomediastinum and adjacent tissues were observed via chest computed tomography. With cooperation of thoracic and cardiovascular surgery department, emergency incision and drainage with drain insertion was done to remove abscess, and control the infection. After surgery, everyday saline irrigation through drain was done during hospitalization, with continues antibiotic therapy. Descending necrotising mediastinitis is a most rare and dangerous infection which occurs on oropharyngeal area. In case of descending necrotising mediastinitis, accurate diagnosis, airway maintenance, remove of abscess by incision and drainage, aggressive antibiotic therapy and continuous saline irrigation is necessary to increase patient survivability. Also, computed tomography with contrast media is essential to figure out the size and location of the infection and abscess formation.

Pathways and genes of DNA double-strand break repair associated with head and neck cancer

DNA double-strand breaks (DSBs) occur commonly in the all living and in cycling cells. They constitute one of the most severe form of DNA damage, because they affect both strand of DNA. DSBs result in cell death or a genetic alterations including deletion, loss of heterozygosity, translocation, and chromosome loss. DSBs arise from endogenous sources like metabolic products and reactive oxygen, and also exogenous factors like ionizing radiation. Defective DNA DSBs can lead to toxicity and large scale sequence rearrangement that can cause cancer and promote premature aging. There are two major pathways for their repair: homologous recombination(HR) and non-homologous end-joining(NHEJ). The HR pathway is a known "error-free" repair mechanism, in which a homologous sister chromatid serves as a template. NHEJ, on the other hand, is a "error-prone" pathway, in which the two termini of the broken DNA molecule are used to form compatible ends that are directly ligated. This review aims to provide a fundamental understanding of how HR and NHEJ pathways operate, cause genome instability, and what kind of genes during the pathways are associated with head and neck cancer.

Pathways and genes of DNA double-strand break repair associated with head and neck cancer

DNA double-strand breaks (DSBs) occur commonly in the all living and in cycling cells. They constitute one of the most severe form of DNA damage, because they affect both strand of DNA. DSBs result in cell death or a genetic alterations including deletion, loss of heterozygosity, translocation, and chromosome loss. DSBs arise from endogenous sources like metabolic products and reactive oxygen, and also exogenous factors like ionizing radiation. Defective DNA DSBs can lead to toxicity and large scale sequence rearrangement that can cause cancer and promote premature aging. There are two major pathways for their repair: homologous recombination(HR) and non-homologous end-joining(NHEJ). The HR pathway is a known "error-free" repair mechanism, in which a homologous sister chromatid serves as a template. NHEJ, on the other hand, is a "error-prone" pathway, in which the two termini of the broken DNA molecule are used to form compatible ends that are directly ligated. This review aims to provide a fundamental understanding of how HR and NHEJ pathways operate, cause genome instability, and what kind of genes during the pathways are associated with head and neck cancer.

schwannoma developed from trigeminal nerve

Schwannoma named neurinoma, peripheral glioma, perineural fibriblastoma and Neurilemmoma is a ectodermal benign neoplasm which originates from schwann cell or neuro axons. It usually develops in peripheral systems of sensory nerves of gastrointestinal tract, oral cavity, and bone. It occurs more frequently in soft tissue than hard tissue, and is extremely rare in intraoral area. We report a case of Schwannoma that showed large mass on buccal cheek with Rt. midfacial swelling, pain, tenderness to palpation and involvement with maxillary branch of trigeminal nerve. We present this case and review the literature.