Characteristics of temporomandibular joint structures after mandibular condyle fractures revealed by magnetic resonance imaging / 대한악안면성형재건외과학회지

BACKGROUND: This study aimed to evaluate the structural changes of temporomandibular joint immediately after condylar fractures with magnetic resonance imaging (MRI). METHOD: We evaluated 34 subjects of condylar fractures with MRI. The position, shape, and signal intensity of the condyle, disc, and retrodiscal tissue were analyzed with MR images. RESULTS: Immediately after trauma, the disc was displaced with the fractured segment in almost all cases. And, the changes of signal intensity at the retrodiscal tissue were found but less related to the degree of fracture displacement. And, the high signals were observed almost at all fractured joint spaces and even at some contralateral joints. CONCLUSIONS: The displaced disc as well as the increased signal intensity of the joint space, condylar head, and retrodiscal tissue demands more attention to prevent the possible sequela of joint.

Fabrication of palatal lift prosthesis using thermoplastic resin for a patient with velopharyngeal insufficiency / 대한치과보철학회지

Recently, flexible removable prosthesis with thermoplastic resin clasp has increasingly become popular. In comparison with conventionally used acrylic resin, thermoplastic resin has lower flexural strength and elastic modulus. Thus, flexible removable prosthesis has low risk of fracture, so denture base can be made thin and light, increasing patient comfort. Also, it can passively sit at tooth undercut during rest, so abutment teeth need minimum or no preparation. In this case report, a 44 year old female patient with mild velopharyngeal insufficiency was treated with a palatal lift prosthesis made of polyester thermoplastic resin. Since the patient had no missing tooth and desired conservative treatment, the flexible removable prosthesis provided relatively satisfactory results.

Positional symmetry of porion and external auditory meatus in facial asymmetry / 대한악안면성형재건외과학회지

BACKGROUND: The porion (Po) is used to construct the Frankfort horizontal (FH) plane for cephalometrics, and the external auditory meatus (EAM) is to transfer and mount the dental model with facebow. The classical assumption is that EAM represents Po by the parallel positioning. However, we are sometimes questioning about the possible positional disparity between Po and EAM, when the occlusal cant or facial midline is different from our clinical understandings. The purpose of this study was to evaluate the positional parallelism of Po and EAM in facial asymmetries, and also to investigate their relationship with the maxillary occlusal cant. METHODS: The 67 subjects were classified into three groups. Group I had normal subjects with facial symmetry (1.05 +/- 0.52 mm of average chin deviation) with minimal occlusal cant (<1.5 mm). Asymmetry group II-A had no maxillary occlusal cant (average 0.60 +/- 0.36), while asymmetry group II-B had occlusal cant (average 3.72 +/- 1.47). The distances of bilateral Po, EAM, and mesiobuccal cusp tips of the maxillary first molars (Mx) from the horizontal orbital plane (Orb) and the coronal plane were measured on the three-dimensional computed tomographic images. Their right and left side distance discrepancies were calculated and statistically compared. RESULTS: EAM was located 10.3 mm below and 2.3 mm anterior to Po in group I. The vertical distances from Po to EAM of both sides were significantly different in group II-B (p = 0.001), while other groups were not. Interside discrepancy of the vertical distances from EAM to Mx in group II-B also showed the significant differences, as compared with those from Po to Mx and from Orb to Mx. CONCLUSIONS: The subjects with facial asymmetry and prominent maxillary occlusal cant tend to have the symmetric position of Po but asymmetric EAM. Some caution or other measures will be helpful for them to be used during the clinical procedures.

Three-dimensional functional unit analysis of hemifacial microsomia mandible-a preliminary report / 대한악안면성형재건외과학회지

BACKGROUND: The aim of this study was to present three-dimensional (3D) structural characteristics of the mandible in the hemifacial microsomia. The mandible has six distinct functional units, and its architecture is the sum of balanced growth of each functional unit and surrounding matrix. METHODS: In order to characterize the mandibular 3D architecture of hemifacial microsomia, we analyzed the mandibular functional units of four hemifacial microsomia patients using the 3D reconstructed computed tomography (CT) images. And we compared the functional unit size between affected and non-affected side. RESULTS: The length of condyle and angle showed significant differences between affected and non-affected sides. However, the length of mandibular body showed insignificant differences. The size differences between affected and non-affected side were observed at the condyle, angle, and body in descending order. CONCLUSIONS: This preliminary study suggests that the main etiopathogenic units are condyle and angle in the hemifacial microsomia mandible. Further investigation with the increased number of subjects will be helpful to establish treatment modality by etiopathogenic targeting of hemifacial microsomia.

Development of New Orthognathic Model Surgery Technique Based on the Reference Points onto the Teeth and the Use of Occlusal Index

Reconsideration of decision making for third molar extraction

INTRODUCTION: Third molar extraction is one of the most common procedures in oral and maxillofacial surgery. The impacted third molar causes many pathological conditions, such as pericoronitis, caries, periodontitis, resorption of adjacent teeth, and cyst or tumors associated with impacted teeth. Extraction is often considered the treatment of choice for impacted lower third molars. On the other hand, imprudent extraction of deeply impacted third molars can cause permanent complications, such as inferior alveolar nerve damage. Therefore, guidelines for the extraction of lower third molars should be set to prevent embarrassing complications. This study examined the indication and current trends of the extracted lower third molars in the dental hospital of a dental college. MATERIALS AND METHODS: 557 extracted third molars were evaluated at the department of oral and maxillofacial surgery of Yonsei University. The chief complaint, diagnosis, age and degree of impaction were analyzed to determine the tendency for the extraction of asymptomatic lower third molars. RESULTS: The percentage of asymptomatic third molars was 40.8%. In cases of full impacted tooth or full erupted tooth, the percentage of asymptomatic teeth was more than 50% (52.4% and 54.3, respectively). Among those partially impacted teeth, 73.1% of them showed symptoms, such as pain, tenderness and swelling. In terms of age, pericoronitis was evident at a younger age, and dental caries/periodontitis was the main cause of removal in those aged over 50. Twenty nine cases (1.6%) had teeth associated with pathological changes. CONCLUSION: The incidence of pathological changes to the lower third molar was relatively low. Surgical extraction is recommended in cases of partially impacted teeth. In Korea, the incidence of asymptomatic third molar extraction was relatively higher than in European countries. More careful attention would be desirable to consider the risks and benefits of lower third molar extraction.

USE OF A COMPUTER NAVIGATION SYSTEM FOR OSTEOTOMIES IN THE ORTHOGNATHIC SURGERY: TECHNICAL NOTE

Erk and retinoic acid signaling participate in the segregation and patterning of first arch derived maxilla and mandible

The Efficacy of Prophylactic Antibiotics for Mandibular Third Molar Extraction

This study analyzed the incidence of wound infection after the operation of mandibular third molar extraction in relation with antibiotic prophylaxis with the object of young and healthy patients. The study object was 1,177 mandibular third molars of 850 men of 20 to 25 years old without any specific systemic disease. Three methods of preventive antibiotic medication were selected according to the preventive antibiotic medication previously reported; three experimental groups were selected based on them, and the antibiotic used was amoxicillin((R)Kymoxin, Yuhanyanghaeng, Seoul). The group 1 includes the patients that took the antibiotic orally before the operation(one hour earlier, 500mg) and for three days after the operation(250mg per time, three times/day), the group 2 is the ones that took the same antibiotic orally only once about one hour before the operation(500mg), and the group 3 did not take any antibiotics before and after the operation. And to compare the difficulties and the degrees of extraction during operations which can be possibly related to the wound infection after the operations, the mandibular third molars' impacted depths and extraction methods were investigated as well. To check if the wound was infected, observations with an internal of one week were performed twice after the operation, and the meaningfulness of the infection incidence was verified through Chi-square test using SPSS program(SPSS Inc., IL, USA). There was no statistically significant difference between the antibiotic medication methods and the wound infection incidence after the operation among the experimental groups. As examining the relations between the mandibular third molar operation methods and the wound infection incidence after the operation, there existed a statistically meaningful difference in the infection incidence according to the operation methods(p=0.020). And there was no statistically significant difference in the wound infection incidence according to the impacted depth of the mandibular third molar. Therefore, it is thought that there exists little necessity of prophylatic antibiotics medication when extracting the mandibular third molar of young and healthy men without any systemic disease in general; however, in case when it is expected that the possibility of infection will be high or the wound on the tissue will be severe, it is sure that the prophylactic antibiotics medication will be necessary.

Image fusion accuracy for the integration of digital dental model and 3D CT images by the point-based surface best fit algorithm

PURPOSE: The goal of this study was to develop a technique for creating a computerized composite maxillofacial-dental model, based on point-based surface best fit algorithm and to test its accuracy. The computerized composite maxillofacial-dental model was made by the three dimensional combination of a 3-dimensional (3D) computed tomography (CT) bone model with digital dental model. MATERIALS AND METHODS: This integration procedure mainly consists of following steps : 1) a reconstruction of a virtual skull and digital dental model from CT and laser scanned dental model ; 2) an incorporation of dental model into virtual maxillofacial-dental model by point-based surface best fit algorithm; 3) an assessment of the accuracy of incorporation. To test this system, CTs and dental models from 3 volunteers with cranio-maxillofacial deformities were obtained. And the registration accuracy was determined by the root mean squared distance between the corresponding reference points in a set of 2 images. RESULTS AND CONCLUSIONS: Fusion error for the maxillofacial 3D CT model with the digital dental model ranged between 0.1 and 0.3 mm with mean of 0.2 mm. The range of errors were similar to those reported elsewhere with the fiducial markers. So this study confirmed the feasibility and accuracy of combining digital dental model and 3D CT maxillofacial model. And this technique seemed to be easier for us that its clinical applicability can good in the field of digital cranio-maxillofacial surgery.

Accuracy of digital model surgery for orthognathic surgery: a preclinical evaluation

Intraosseous Nerve Sheath Tumors in the Jaws

Although the head and neck region is recognized as the most common location for peripheral nerve sheath tumors, central involvement, particularly in the jaw bones, is quite unusual. Neurofibroma is one of the most common nerve sheath tumors occurring in the soft tissue and generally appears in neurofibromatosis 1 (NF1 or von Recklinghausen's disease). Malignant peripheral nerve sheath tumors (MPNSTs) are uncommon sarcomas that almost always arise in the soft tissue. Here, we report four cases of intraosseous peripheral nerve sheath tumors occurring in the jaw bones and compare the clinical, radiologic, and pathologic findings in order to make a differential diagnosis.

A Study for The Nature of Pigmentation Adjacent to Titanium Miniplate Osteosynthesis

The titanium miniplate osteosynthesis system has been used for fixation of bone fragments in the maxillofacial areas due to easy manipulation and even has been proposed for unnecessity of miniplate removal because of the biocompatibility and the corrosion resistance. But recently, there have been some suggestions for its removal, on the basis of findings that there have been pigmentations around the adjacent tissues during miniplate removal procedure and they are the depositions of metal particles. Purposes of this study are to ascertain the presence and nature of pigmentation observed within tissues adjacent to titanium miniplate, and to suggest possible causes of it. We could observe the black pigmentation during miniplate removal procedure for recent about 1.5 year. Pigmented tissues were stained with hematoxylin-eosin(H-E) for light microscophic(LM) examination to investigate the black pigmentations and the histomorphology around them. The scanning electron microscopy(SEM) with energy dispersive X-ray(EDX) analysis was used to examine the ultrastructural nature of pigmentations. Many metal particles with variable sizes and shapes were seen in the connective tissue by SEM and were identified as titanium by EDX.

The Accuracy of measurements during model surgery for orthognathic planning

The errors in orthognathic surgery can occur during the preoperative preparations including the model surgery, but till now there's been some lack of reserches about them. So we wanted to verify the accuracies in measurements used in model surgery. We compared the accuracy of measurements by vernier calipers, which has been the main measurement tool for conventional model surgery, and that by height gauge, which is recently claimed to be more accurate, with 3 dimensional coordinate analyzer. We could have following results and have a plan to use them for the invention of new model surgery techniques. 1. The measurement errors in Group 1, which mean the difference between "the measurements by 3-D analyzer" and "the measurements by height gauge", were small enough with the range of 0.1~0.2mm in all planes. 2. The mean error in Group 2, which is the differences between the measurements of 3-D analyzer and those of vernier calipers, was 1.1mm. 3. The measurement errors in Group 2 were variable according to the factors including the differences of individuality and expertness of each measurers. But in case of Group 1, they were small and not variable by the expertness. 4. The measurements were more accurate at the points in anterior teeth than in molar teeth in Group 1 and 2. 5. The errors after model surgery increased remarkably, compared with those before surgery in Group 2. And the situation was different in Group 1 in that errors decreased after surgery. Accoding to these results, it assumed that the measurements with height gauge during the model surgery for orthognathic surgery are accurate enough and can be maintained, regardless of complexity of models, individuality, or expertness of measurers.

A clinicostatistical analysis of mandibular fractures in the west of gyeongsangnamdo

A Clinico-Statistical Analysis On The Fascial Space Infections Of Oral And Maxillofacial EGION

We have conducted a retrospective study of 224 patients with the diagnosis of oral and maxillofacial infection who had been treated between 1988 and 1999 at Gyeong-Sang National University Hospital. This study was aimed to furnish the data of oral and maxillofacial infection and to aid diagnosis and treatment. The most common fascial space involved, as determined by clinical, radiologic, and operative findings, were the submandibular space(39.4%). The most frequent cause of oral and maxillofacial infection was odontogenic 68.8%. In the odontogenic cause, dental caries was the most common cause. Two-hundred three patients required surgical drainage of the abscess. Seventeen patients needed tracheostomy for airway control. The overall mortality was 0.9% despite aggressive anti-microbial therapy and early surgical intervention. All other patients had an uneventful recovery without major complication except osteomyelitis case(6.0%). The combination of early radiologic diagnosis, effective antimicrobial therapy, and intensive surgical management contributed to the good prognosis.

MR Imaging of the Temporomandibular Joint in Patient with Acute Mandibular Condylar Fracture

PURPOSE: To analyze various MR imaging findings and thus evaluate the usefulness of MR imaging of the tem-poromandibular joint in patient with acute mandibular condylar fracture. MATERIALS AND METHODS: MR imaging was performed within 1week after trauma in 25 patients (total joints s-tudied=31) in whom condylar fracture had been diagnosed by simple radiographs. We analyzed the signal intensity of bone marrow and disk, displacement of bone fragment and disk, deformity. In addition, MRI findings of retrodiskal tissue, joint capsule and joint effusion were eualuated. RESULTS: No abnormal signal intensity was noted in bone marrow or disk. Displacement of a condylar fracture fragment was observed in 24 joints(77 %) (anteromedial, 63 %; medial, 25 %; anterior, 4%; anterolateral, 4 % ; and lateral, 4 %). Disk displacement occurred in 23 joints(74 %) (anteromedial, 65 %; medial, 9 %; anterior, 18%; anterolateral, 4 %; and lateral, 4 %). In 17 joints (55 %) the disk was displaced along with the fractured condylar fragment, and disk deformity was noted in five joints(16 %). MR imaging (T2WI) revealed a capsular tear(n=1), joint effusion(n=26), and high signal intensity in the retrodiskal tissue(n=6). CONCLUSION: MR imaging provided information concerning condylar fragments, disks, retrodiskal tissue, capsules, and joint effusion. In patients with acute mandibular condylar fracture, MRI is therefore useful for evaluation of the temporomandibular joint.

Managements Of Liver Cirrhosis Patients In Oral And Maxillofacial Surgery -Case Reports

To evaluate the pathophysiology and surgical considerations for liver cirrhosis in the field of oral and maxillofacial surgery, 4 cases with maxillofacial traumas or infections in different stages of liver cirrhosis were reviewed. Although appropriate medical cares were ensured, 2 patients were died due to complications of the liver disease. Each cases were classified by the Pugh's classification system and analyzed with reference to laboratory findings and hospital courses. For improved understandings of pathophysiology of liver cirrhosis, the congulopathies, the lowered detoxification, the hepatic encephalopathy, the hepatorenal syndrome, the sepsis, other conditions-ascites, esophageal varix, portal hypertension, etc-and pre or postoperative complications were reviewed. And special emphases were made at the staging of liver cirrhosis in oral and maxillofacial surgery, preoperative preparations, and prevention of intraoperative or postoperative complications.

Atelectasis Due to Epistaxis Aspiration during Awake Fiberoptic Nasotracheal Intubation / 대한구급학회지

Indication for fiberoptic intubation in an awake patient include almost any abnormality that may hinder the expeditious placement of an endotracheal tube during anesthetic induction. An epistaxis is the most frequent complication of nasotracheal intubation. The patient was admitted for open reduction and internal fixation due to severe mandible fracture. We experienced a case of atelectasis due to epistaxis aspiration during awake fiberoptic nasotracheal intubation in the conscious patient regionally anesthetized by both superior laryngeal nerve block and translaryngeal anesthesia, which is treated by saline irrigation, suction, active coughing and chest percussion.

Effect of Positive End-Expiratory Pressure on Intraocular Pressure in the Critically Ill and Mechanically Ventilated Patients / 대한구급학회지

BACKGOUND: The purpose of this study was to examine the effect of various levels of positive end-expiratory pressure (PEEP) on the intraocular pressure in the patients receiving positive pressure ventilation. METHODS: Twenty, critically ill sedated and hemodynamically stable patients without history of glaucoma were placed on controlled positive pressure ventilation. Measured variables included intraocular pressure (IOP), mean arterial pressure (MAP), central venous pressure (CVP), peak inspiratory pressure (PIP) and arterial blood gas analysis (ABGA), and were recorded at zero end-expiratory pressure (ZEEP), and at 5, 10, 15, 20 cmH2O PEEP, applied in random order. RESULTS: IOP increased significantly from 13+/-3 to 16+/-3 mmHg at 15 cmH2O PEEP and from 14+/-4 to 17+/-6 mmHg at 20 cmH2O PEEP. CVP increased significantly from its corresponding ZEEP measurements at all PEEP levels and from 14+/-4 cmH2O at 5 cmH2O PEEP to 21+/-4 cmH2O at 20 cmH2O PEEP. There was a positive correlation between PEEP levels and PIP or CVP but no relationship between PEEP levels and IOP was observed. CONCLUSIONS: The application of PEEP levels > or = 15 cmH2O resulted in a significant increase in the IOP of patients with normal basal ocular tonometry. This study suggests that further increase in IOP may occur in the mechanically ventilated patients with already increased IOP or normal-tension glaucoma, when higher levels of PEEP are used.