Mini-implants to restore missing teeth in severe ridge deficiency and small interdental space

Etiology and Patterns of Maxillofacial Fractures in 518 patients in Korea

PURPOSE: Different patterns in the causes of maxillofacial injury are thought to correlate with socioeconomic status and regional environment. This study investigated maxillofacial fractures in order to analyze maxillofacial trauma characteristics and the relationship between the causes and injury patterns in Korea. MATERIAL AND METHODS: A total of 518 patients with maxillofacial fractures who were treated at the Seoul National University Boramae Hospital between 1996 and 2004 were retrospectively analyzed. Data were obtained from the patients' medical records and radiographs. The male to female ratio in the patient group was 2.78:1, and the mean age was 32.3 years. RESULTS: Midfacial fractures were the most common location of injury (46.1%). The most common etiologic factor was an activity associated with daily life (42.6%) including falls, stumbling, and collisions. The second most common cause was assault (32.4%), followed by traffic accidents (13.7%). In the case of midfacial fractures and mandibular fractures, assault was the most common etiologic factor, whereas in the case of alveolar bone fractures, activities associated with daily life were the most common cause. With regard to age groups, assault was the most common cause for patients between 10 and 39 years old and an activity associated with daily life was the most common cause in those under 10 years and over 40 years. CONCLUSIONS: This study concluded that activities associated with daily life and assault causes a large proportion of Korean maxillofacial injuries and that preventive measures should be implemented in order to minimize these risks.

Maxillary sinus augmentation with bovine bone mineral (bio-oss.) and the maxillary tuberosity

The aim of this study was to evaluate implant stability placed in the maxillary sinus which was augmented with bovine bone mineral (Bio-Oss.) mixed with autogenous bone from the maxillary tuberosity. Maxillary sinus floor augmentation with the mixture of bovine bone mineral and autogenous maxillary tuberosity bone was performed in 30 maxillary sinuses, and 68 implants were placed at the time of sinus graft. After 6 months of implant placement abutments were connected and implant stability quotient (ISQ) was measured by radio frequency analysis (RFA). In addition, bone level changes was evaluated by taking periapical radiograph. During surgical procedures, no complication was observed, and all patients healed uneventfully. At 6 months the implant showed stable ISQ values. The marginal bone level changes around the fixtures was stably maintained through out the follow up period. This study confirmed that maxillary sinus floor augmentation with mixture of bovine bone mineral and maxillary tuberosity bone could be reliable for bone regeneration in subantral space.

The effect of pulsed electromagnetic fields on beta-TCP graft in rabbit cranial bone defect

The purpose of this research was to investigate whether pulsed electromagnetic field (PEMF) stimulation applied to the rabbit cranial defects grafted with beta-tricalcium phosphate (beta-TCP) could affect the new bone formation. With 16 New Zealand white rabbits under the same condition, bilateral calvarial bone defects were formed around the sagittal suture line. The defect on the left side was grafted with beta-TCP, while on the right side was grafted by harvested autogenous bone. PEMF was applied to 8 rabbits for 8 hours per day. The bony specimen were divided into 3 groups, the group 1 was autogenous bone grafted specimen, the group 2 was beta-TCP grafted with PEMF, and the group 3 was beta-TCP grafted without PEMF. We investigated the bone regeneration and growth factor expression at 2, 4, 6, and 8 weeks. As a result, BMP 2 was expressed in the group 1 from 2 weeks, the group 2 from 4 weeks, and the group 3 from 6 weeks. BMP 4 was expressed in the group 1 from 2 weeks, in the group 2 and the group 3 from 4 weeks. 4. There was no significant difference in expression pattern of BMP 7, PDGF, VEGF, and TGF-beta1 during grafted bone regeneration in group 1, 2, and 3. According to our results, PEMF stimulation could be effective on the new bome formation in animal study, and have a feasibility of clinical use.

Midfacial measurement using occlusal maxillary CT and surgical implications of maxillary osteotomies

Etiology and patterns of mandibular fractures

The role of bone morphogenetic protein in the tooth culture

Objectives : The proper development of the facial structures relies upon a sequence of tightly regulated signaling interactions between the ectoderm and mesoderm involving the participation of several families of signaling molecules. Among these, bone morphogenetic proteins (BMPs) have been suggested to be a key signal that regulates the development of the mandible and the initiation and morphogenesis of the teeth. The aim of this study was to examine the artificial development of the mandibular structures and to examine the role of BMPs on tooth morphogenesis and differentiation using an organ culture system. Materials and Methods : The tooth germs from Ed 11.5, 13.5 mice were dissected, and transplanted into the diastema of the mandible primordia. The mandibles containing the transplanted tooth germs were cultured in vitro. During this period, beads soaked with BMP4 were implanted around the transplanted tooth germs. In addition, a diastema block containing the transplanted tooth germ was dissected, then transferred to an adult mouse kidney. After the organ culture, the developing mandibular explant was removed from the kidney and prepared for the tissue specimens. Odontogeneis of the transplanted tooth germs was examined after Hematoxylin-eosin, Masson-trichrome staining. Results : Proliferation and differentiation of the tooth germs cultured in the diastema was observed. In the BMP4-treated tooth germs, the formation of the first and second molars was noted. The crown of the developing tooth showed the formation of a mature cusp with the deposition of enamel and dentin matrix. In conclusion, it was confirmed that BMP4 is involved in the formation of a dental crown and the differentiation of ameloblasts and odontoblasts of the molar tooth during the development of the transplanted tooth germs.

ADENOMATOID ODONTOGENIC TUMOR: REPORT OF A CASE INVOLVING MAXILLARY SINUS

Central tongue reduction for macroglossia

Macroglossia can cause dentomusculoskeletal deformities, instability of orthodontic and orthognathic surgical treatment, and create masticatory, speech and airway management problems. To determine whether a reduction glossectomy is necessary, it will important to identify the signs and symptoms of macroglossia. Development of dentoskeletal changes directly related with tongue size, such as an anterior open bite or a Angle Class III malocclusion tendency, would indicate that reduction glossectomy may be beneficial. For reduction glossectomy, several techniques have been reported. However, in most techniques the tip of tongue is removed. So its excision causes the loss of most mobile and sensitive portion of the tongue, and creates ankylosed, globular tongue. To avoid such problems, central tongue reduction technique have been proposed. This article will introduce central tongue reduction for anterior openbite case associated with macroglossia.