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.
Denture Bases ; Elastic Modulus ; Female ; Humans ; Polyesters ; Prostheses and Implants* ; Tooth ; Velopharyngeal Insufficiency*

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.
Head ; Joints ; Magnetic Resonance Imaging* ; Mandibular Condyle* ; Mandibular Fractures ; Methods ; Temporomandibular Joint*

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.
Chin ; Dental Models ; Facial Asymmetry* ; Maxilla ; Molar ; Orbit

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.
Goldenhar Syndrome* ; Humans ; Mandible

PURPOSE: Maintaining function of dialysis access is very important to end stage renal disease patients, and it is critical for these patients' overall well-bing. This study was performed to evaluate the success rate of endovascular interventions, risk factors and patencies of interventions. METHODS: From January 2008 to June 2010, 315 interventions were performed on 189 patients with malfunctioning hemodialysis access. Angioplastic intervention (n=147), and percutaneous mechanical thrombectomies (n=168) were done to restore flow of vascular access. RESULTS: Most common cause of malfunctioning hemodialysis accesses was stenosis (71%) in autogenous fistula group (AFG) and thrombosis (73%) in prosthetic graft group (PGG). Common stenotic site was juxta-anastomotic area (48%) in AFG, and venous anastomotic area (42%) in PGG, primary patencies of interventions at 6, 12, and 18 months were 67%, 45%, and 37% and secondary patencies were 83%, 66%, and 49%, respectively. Finally, thrombotic events (P=0.005) and numbers of procedure (P=0.000) were independent predictive factors of shorter access patency after endovascular treatment. CONCLUSION: Endovascular treatment in malfunctioning hemodialysis access is highly successful procedure with acceptable primary and secondary patency results. Especially, in the cases of stenotic lesion without thrombosis, percutaneous transluminal angioplasty was successfully done in AFG and PGG.
Angioplasty ; Arteriovenous Fistula ; Constriction, Pathologic ; Dialysis ; Endovascular Procedures ; Fistula ; Humans ; Kidney Failure, Chronic ; Prostaglandins G ; Renal Dialysis ; Risk Factors ; Thrombectomy ; Thrombosis ; Transplants

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.
Aged ; Decision Making ; Hand ; Humans ; Incidence ; Korea ; Mandibular Nerve ; Molar, Third ; Pericoronitis ; Periodontitis ; Risk Assessment ; Surgery, Oral ; Tooth ; Tooth, Impacted

Orthognathic Surgery ; Tooth

Esthetics ; Eye ; Head ; Humans ; Mandibular Nerve ; Maxilla ; Neck ; Orthognathic Surgery ; Osteotomy

Cell Proliferation ; Chimera ; Embryonic Development ; Epithelium ; Female ; Fibroblast Growth Factors ; Mandible ; Maxilla ; Neural Crest ; Phosphotransferases ; Pregnancy ; Tretinoin ; Vertebrates

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.
Congenital Abnormalities ; Dental Models ; Fiducial Markers ; Skull