Chang-Joo Park

Bupivacaine Induces Apoptosis via ROS in the Schwann Cell Line

Local anesthetics have been generally accepted as being safe. However, recent clinical trials and basic studies have provided strong evidence for the neurotoxicity of local anesthetics, especially through apoptosis. We hypothesized that local anesthetics cause neural complications through Schwann cell apoptosis. Among local anesthetics tested on the Schwann cell line, RT4-D6P2T, bupivacaine significantly induced cell death, measured by the methyl tetrazolium (MTT) assay, in a dose- (LD50 = 476 μM) and time-dependent manner. The bupivacaine-induced generation of reactive oxygen species (ROS), which was initiated within 5 hrs and preceded the activation of caspase-3 and poly ADP-ribose polymerase (PARP) degradation, was suggested to trigger apoptosis, exhibited by Hoechst 33258 nuclear staining and DNA fragmentation. Furthermore, concomitant block of ROS by anti-oxidants significantly inhibited bupivacaine-induced apoptosis. Among the local anesthetics for peripheral neural blocks, bupivacaine induced apoptosis in the Schwann cell line, which may be associated with ROS production.

Postoperative Stability After Sagittal Split Ramus Osteotomies for a Mandibular Setback With Monocortical Plate Fixation or Bicortical Screw Fixation

PURPOSE This comparative study was performed to analyze mandibular stability after bilateral sagittal split ramus osteotomies for a mandibular setback with a monocortical plate fixation or bicortical screw fixation. PATIENTS AND METHODS A total of 60 patients with a skeletal Class III malocclusion who underwent sagittal split osteotomies and mandibular setback were included in the present study. Among the patients, 30 were osteosynthesized monocortically with a titanium plate, while the other 30 were osteosynthesized bicortically with positioning screws. This retrospective study used cephalometric radiographs taken preoperatively (T0), and at 1 week (T1), 3 months (T2), and 1 year (T3) postoperatively. The linear and angular changes of the cephalometric landmarks of the chin region were measured at each time period, and the changes of each cephalometric landmark were determined for 4 different time intervals: T0 to T1 (Delta T1), T1 to T2 (Delta T2), T2 to T3 (Delta T3), and T0 to T3 (Delta T4). Postoperative changes in mandibular shape were analyzed using a paired t test to determine the stability of fixation methods. RESULTS The surgical changes (Delta T1) could be characterized as posterior movements of the mandibular body and posterosuperior movements of the chin landmark. The results of the cephalometric analysis at 3 and 12 months postsurgery (Delta T2 and Delta T3) could be characterized as anterosuperior movements of the mandible. In both treatment groups, surgical changes were relatively well maintained. Likewise, analysis of the horizontal and vertical movements of the chin landmarks indicated a similar tendency in both groups. There were no statistically significant differences between the measurements of postoperative changes at each time period after surgery. CONCLUSIONS The findings of our study suggest that there were no significant differences in postoperative changes in mandibular shape in both the monocortical and bicortical fixation groups after sagittal split ramus osteotomy. We concluded that monocortical osteosynthesis using a miniplate could be used to obtain stable postoperative changes after mandibular setback.

Factors for Maxillary Sinus Volume and Craniofacial Anatomical Features in Adults With Chronic Rhinosinusitis

OBJECTIVES To compare the volume of the maxillary sinus, dental factors, and craniofacial anatomical features between control subjects and patients with chronic rhinosinusitis (CRS) and to investigate critical factors for the volumetric change in the maxillary sinus in adults. DESIGN Retrospective case-control study. SETTING Tertiary referral center. PARTICIPANTS Ninety-nine individuals who visited an allergy and sinus center: 52 control subjects (septal deviation; mean age, 32.69 years) and 47 patients with CRS (mean age, 44.43 years). INTERVENTION Cephalometry and computed tomography were performed in all the participants. In blinded tests, dentists investigated the dental status of both groups. MAIN OUTCOME MEASURES Maxillary sinus: bone thickness and volume on computed tomography; craniofacial anatomical features: linear and angular variables in lateral cephalometry; and dental evaluation: malocclusion class, teeth status, and alveolar bone height. RESULTS Bony wall thickness of the maxillary sinus significantly increased in patients with CRS (P < .001) but showed no relationship with maxillary sinus volume. Maxillary sinus volume significantly decreased in patients with CRS (P = .001). Age and alveolar bone height had a negative effect on maxillary sinus volume in both groups. Abnormal teeth had no relationship with maxillary sinus volume in both groups but showed a negative effect on alveolar bone height in the CRS group (P = .02). Class II malocclusion associated with anterior movement of the maxilla significantly increased in the CRS group (P = .006). CONCLUSIONS Regardless of CRS, maxillary sinus volume decreased with older age and increased with alveolar bone loss. Regarding craniofacial anatomical features, CRS may have an effect on malocclusion in adults.

Only tetracaine and not other local anaesthetics induce apoptosis in rat cortical astrocytes

BACKGROUND The potential risks of neurotoxicity due to local anaesthetics after regional anaesthesia have been suggested recently. To evaluate the neurotoxicity of commonly used local anaesthetics, primary cultured rat cortical astrocytes were treated with lidocaine, ropivacaine, bupivacaine, levobupivacaine, and tetracaine. METHODS Cell death after local anaesthetic treatment was evaluated with a lactate dehydrogenase (LDH) assay. To examine the mechanisms of cell death, reactive oxygen species (ROS) measurement and western blots of poly-ADP ribose polymerase (PARP), procaspase-3, and mitogen-activated protein kinases family members were performed. RESULTS Of the local anaesthetics, which were applied at <1 mM for 18 h, only tetracaine significantly increased LDH leakage (P<0.05) and cell death in a dose- and time-dependent manner. Hoechst 33258-propidium iodide staining and western blots with PARP and procaspase-3 antibodies suggested that tetracaine induced apoptosis. ROS levels increased 2-fold at 30 min after tetracaine treatment compared with the control and then decreased. The antioxidants, N-acetylcysteine and trolox, markedly inhibited tetracaine-induced apoptosis. CONCLUSIONS Tetracaine induced apoptosis through ROS generation. Further studies focusing on the neurotoxicity of tetracaine are needed.

Miniscrew-anchored alveolar distraction for the treatment of the ankylosed maxillary central incisor

This report presents the case of a 20-year-old female patient exhibiting an infraoccluded ankylosed maxillary central incisor that was avulsed and replanted after traumatic injury during childhood. To reposition the osseous and gingival margins of the ankylosed tooth to an ideal level, a new alveolar distraction device that uses anchoring miniscrews with a single tooth dento-osseous osteotomy was fabricated and the ankylosed tooth was successfully treated with exceptional patient compliance.

Gingival Metastasis from Gastric Adenocarcinoma

The oral cavity is a rare but occasional target for metastases, which may masquerade as various benign and inflammatory lesions. Also, occult cancer may metastasize to the oral cavity as a first and exclusive manifestation. It is important to bear these possibilities in mind because such situations may be encountered during a routine examination of the head and neck region. A 58-year-old man was referred to the Department of Dentistry/Oral and Maxillofacial Surgery because of a 2-month history of a painful swelling of upper right first molar area. Past medical history was significant for subtotal gastrectomy for adenocarcinoma of the stomach (stage IIIa: T3 N1 M0) at the age of 54. Following surgery, he received six cycles of chemotherapy with 5-fluorouracil, adriamycin, and mitomycin-C. At that time, no metastasis was found on abdominal computed tomography (CT) scan. Six months later, abdominal CT and endoscopic examination showed no recurrence or metastasis. However, 4 years later, pulmonary and hepatic metastases appeared, and whole body bone scan detected multiple metastatic rib, pelvis, and femoral bone lesions. Consequently, the patient was admitted for chemotherapy and referred to our department during the chemotherapy. Clinically, intraoral examination revealed soft tissue swelling, resembling periodontal pyogenic abscess of granuloma-like hyperplastic lesions. The lesion was located on the buccal gingiva and vestibule and measured approximately 3.0 2.0 cm (Fig 1A). The exophytic growth, in the first and second molar region, was associated with pain, foul odor, and a bloody and necrotic tag. The extraoral head and neck examination showed no evidence of lymphadenopathy or other pathology. Radiographic examination demonstrated horizontal bone loss in the first and second molar region. Facial CT showed a 2.0 1.5-cm soft tissue mass on the lateral right maxilla near the second molar. The bony defect was found on the inferior-lateral wall of the right maxillary sinus. However, there was no change on the sinus mucosa (Fig 1B). After the patient was provided written informed consent, the incisional biopsy was performed to confirm clinical diagnosis of this gingival mass. Histopathologically, biopsy

Lemierre's Syndrome Originated from the Odontogenic Infection: A Case Report

Also called necrobacillosis or postanginal sepsis, Lemierre’s syndrome (LS) is an uncommon but potentially lethal complication of odontogenic infection. A 27-year-old male diagnosed with Ludwig’s angina was transferred from a local hospital due to continuous fever and chills after incision and drainage under general anesthesia. The swelling of both submental and submandibular area subsided, but the fever and chills persisted. While generalized malaise improved, sepsis developed together with the deterioration of liver function. The chest computed tomography scan revealed multiple cavitations throughout both lungs, which were diagnosed as septic pulmonary embolism. After consulting the department of infectious diseases, the patient was treated with intravenous antibiotics focusing on vancomycin and additional antibiotics. After 3 weeks of treatment, the patient recovered completely. Despite its decreased mortality, dentists are not familiar with LS, and it is diffi cult to diagnose correctly. In this paper, we report a case and present a review of literature.

Preliminary evaluation of a three-dimensional, customized, and preformed titanium mesh in peri-implant alveolar bone regeneration

Objectives The purpose of this preliminary study is to evaluate the effectiveness of a customized, three-dimensional, preformed titanium mesh as a barrier membrane for peri-implant alveolar bone regeneration. Materials and Methods Ten patients were recruited for this study. At the time of implant placement, all patients had fenestration or a dehiscence defect around the implant fixture. A mixture of particulate intraoral autologous bone and freeze-dried bone allograft was applied to the defect in a 1 : 1 volume ratio and covered by the preformed titanium mesh. A core biopsy specimen was taken from the regenerated bone four months postoperatively. Patients were followed for 12 months after the definitive prosthesis was placed. Results Satisfactory bone regeneration with limited fibrous tissue was detected beneath the preformed titanium mesh. Histologic findings revealed that newly formed bones were well-incorporated into the allografts and connective tissue. New growth was composed of approximately 80% vital bone, 5% fibrous marrow tissue, and 15% remaining allograft. All implants were functional without any significant complications. Conclusion The use of preformed titanium mesh may support bone regeneration by maintaining space for new bone growth through its macro-pores. This preliminary study presents the efficacy of a preformed titanium mesh as a ready-to-use barrier membrane around peri-implant alveolar bone defect. This preformed mesh is also convenient to apply and to remove.

The Effect of Osteopontin and an Osteopontin-Derived Synthetic Peptide Coating on Osseointegration of Implants in a Canine Model.

Osteopontin (OPN) and an OPN-derived synthetic peptide, OC-1016, have demonstrated their potential to enhance osseointegration in vitro. The purpose of this study was to evaluate bone-to-implant contact (BIC) and surrounding bone density (BD) of implants coated with either recombinant human OPN (rhOPN) or OC-1016 as compared with noncoated titanium plasma sprayed (TPS) surface in a canine model. Histomorphometric analysis revealed that at 4 weeks, %BIC and %BD of coated implants were significantly higher than those of noncoated TPS implants. At 12 weeks, %BIC of coated implants was also significantly higher than that of noncoated implants; however, there was no statistically significant difference in %BD. The rhOPN and OC-1016 were concluded to be capable of significantly accelerating the early stage of osseointegration and bone healing around implants.

Anterior maxillary defect reconstruction with a staged bilateral rotated palatal graft.

Purpose In the anterior maxilla, hard and soft tissue augmentations are sometimes required to meet esthetic and functional demands. In such cases, primary soft tissue closure after bone grafting procedures is indispensable for a successful outcome. This report describes a simple method for soft tissue coverage of a guided bone regeneration (GBR) site using the double-rotated palatal subepithelial connective tissue graft (RPSCTG) technique for a maxillary anterior defect. Methods We present a 60-year-old man with a defect in the anterior maxilla requiring hard and soft tissue augmentations. The bone graft materials were filled above the alveolar defect and a titanium-reinforced nonresorbable membrane was placed to cover the graft materials. We used the RPSCTG technique to achieve primary soft tissue closure over the graft materials and the barrier membrane. Additional soft tissue augmentation using a contralateral RPSCTG and membrane removal were simultaneously performed 7 weeks after the stage 1 surgery to establish more abundant soft tissue architecture. Results Flap necrosis occurred after the stage 1 surgery. Signs of infection or suppuration were not observed in the donor or recipient sites after the stage 2 surgery. These procedures enhanced the alveolar ridge volume, increased the amount of keratinized tissue, and improved the esthetic profile for restorative treatment. Conclusions The use of RPSCTG could assist the soft tissue closure of the GBR sites because it provides sufficient soft tissue thickness, an ample vascular supply, protection of anatomical structures, and patient comfort. The treatment outcome was acceptable, despite membrane exposure, and the RPSCTG allowed for vitalization and harmonization with the recipient tissue. Graphical Abstract