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open access
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ISSN : 0376-4672
Purpose: To measure the head tilting angle creating initial condylar cut-off and to find the head position inducing the superimposition of the cervical vertebrae over the mandibular ramus on panoramic radiograph. Materials and Methods: The panoramic radiographs were taken with Didactic skull on cervical spine model (Scientific GmbH, Hamburg, Germany) using Kodak 8000c Digital Panoramic radiography. For the inherent radiolucency of the plastic skull model, radiopaque 1 mm diameter lead wires were attached along the margin of the mandibular condyle, ramus, mandibular body, cervical vertebrae, and FH plane of the skull model. For measuring the head tilting angle creating the condylar head cutoff, panoramic radiographs were taken by tilting the FH plane downward in 5 degree increments. For finding the distance between transverse process of the third cervical vertebra and gonion inducing superimposition of cervical vertebrae on the mandibular ramus, panoramic radiographs were taken by decreasing the distance in 0.5 cm increments. Result and Conclusion: The condylar cutoff began to appear when the head of skull model was tilted downward by 15o. As the head tilting angle increasing, the condylar cutoff became more prominent. The superimposition of cervical vertebrae over the mandibular ramus began to appear when the distance between the gonion and third cervical vertebra was 1.0 cm. As the distance decreasing, the superimpostion became more prominent.
In the posterior maxillary area, due to resorption of the ridge after extraction and pneumatization of the maxillary sinus, the height of the alveolar ridge may not be sufficient for placement of implants. To solve this problem, sinus augmentation using both crestal and lateral approaches have been widely used. Jung et al. (2010) introduced the modified lateral approach technique, which is a simplified technique that combines the advantages of crestal and lateral approaches. The purpose of this case report is to report two cases in the posterior maxilla in which simultaneous implant placement with maxillary sinus augmentation has been performed using the modified lateral approach technique. In two female patients, 67 and 74 years old, respectively, simultaneous implant placement was performed using the modified lateral approach technique on the left maxillary second premolar and the first molar. In both patients, the residual bone height on the distal side of the maxillary second premolar was measured to be approximately 5 mm, and the residual bone height of the first molar was measured to be 2-3 mm. After flap elevation, osteotomy of the lateral window was performed in the form of a mesiodistally extended slot above the sinus floor and the Schneiderian membrane was elevated. Sequenced drilling was performed while protecting the membrane with a periosteal elevator. Bone graft and implant placement was performed after preparation of the implant site. Sufficient primary stability was achieved for each implant and sinus membrane was not perforated. After four and five months respectively, implant second surgery was performed. Clinically, the implants were observed to be stable. Implants and surrounding peri-implant mucosa were well maintained after prosthodontic treatment. In conclusion, the modified lateral approach could be a predictable and efficient technique for implant placement in the atrophied posterior maxilla.
Polyaryletherketone (PAEK) is recently introduced in dentistry. The polymer has superior mechanical and chemical properties compared to previous dental materials. PAEK has been explored for lots of applications for clinical dentistry. The prostheses can be made by the injection molding or milling techniques. Recent studies focus on improving the bioactivity of PAEK and expanding the application. The purpose of this article is to introduce the basic features, chemical structure and various clinical applications in fixed dental prostheses. Further research and clinical trials will be needed to confirm the usability of PAEK in the routine practice.
The zirconia-reinforced lithium silicate ceramic material is a material in which lithium silicate glass contains about 10% by weight of zirconia oxide (zirconia oxide). This material has both the advantages of glass ceramics and zirconia, and it is attracting attention as a CADCAM material for single tooth restoration. ZLS materials have improved strength compared to widely used e.max (lithium disilicate ceramic) materials. It can be used for single crown restoration and ensuring a thickness of 1.5 mm is very important for reliable treatment. In the case of Celtra Duo, heat treatment may be helpful in terms of strength and abrasion resistance. Hydrofluoric acid treatment is helpful for bonding and hydrofluoric acid for a short time may not help to improve the bonding strength. Although zirconia-reinforced lithium silicate ceramic materials have been continuously conducted and published in the laboratory, reliable clinical studies are still lacking. Additional clinical studies will be a very important part of establishing a scientific basis.
The development of dental materials has widened the scope of materials by changes in processing methods. CAD/CAM processing enables the use of zirconia as a dental material. Recent esthetic materials development has been made. For aesthetic purposes, a block for CAD/CAM processing by mixing polymer and ceramic materials are fabricated. However there is no guideline of how these materials should be used in actual clinical practice. Mechanical properties, wear and clinical studies were reviewed.