Lately, the improvement of dental implant treatment has been growing faster. This is surely based on the conception, which was established by Professor Brånemark and his groups.
The present implant treatment is considered to be in the directions of followings;
1 . Hard tissue augmentation techniques for top down treatment
2 . Immediate and early loading
3 . Clarification of risk factors
4 . Management of implants in esthetic zone
5 . Patient safety and quality assurance
However, some treatments provide only clinical techniques, with few evidences and no consensus. It is needed to understand and distinguish the treatments for implant treatment with a consensus from the ones, which are still under experiments.
For more growth of Dental Implantology in the future, the development of “Biofunctional Implants” by improving of dental implant surfaces is expected.

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During morphogenesis of the secondary palate, medial edge epithelium(MEE)is formed by fusion of the opposing epithelia covering the tips of the palatal shelves. Thereafter, MEE disappears from the mesenchymal tissue at the appropriate time, and palatal fusion is completed. While this developmental phenomenon has long been known, the mechanisms underlying MEE disappearance remain to be elucidated. Previous studies have shown that MEE loss is due to factors such as apoptosis, shedding of periderm into the body cavity, epithelialmesenchymal transformation, and macrophage phagocytosis.
The present study focused on the role of cell migration. ICR mouse fetuses(E14)were studied. Frontal sections were prepared, and those in stages from contact of the palatal shelves to the start of MEE disappearance were analyzed. For each specimen, 5-μm continuous sections were prepared, and the secondary palate(from the tip of the soft palate to the site of fusion of the nasal septum)was stained using hematoxylin and eosin(HE)at10-μm intervals. We used 3-dimensional stomatognathic reconstruction software(TRY/3D-SRF). The outline of epithelial tissue, mesenchymal tissue, and apoptotic bodies were extracted to reconstruct 3-dimensional images.Each of the extracted data were superimposed and examined.
The results showed that when palatal shelves came in contact, a multilayer epithelial seam was formed, and many apoptotic bodies were observed.
In addition, once the epithelia came in contact, an epithelial triangle was formed on the side of the nasal and oral cavities, and the width of the central MEE narrowed. This phenomenon was attributed to epithelial cell migration.
Furthermore, epithelial disappearance did not occur sequentially from the anterior region of the hard palate to the soft palate in a unidirectional manner, but occurred simultaneously wherever contact was made. At the sametime, apoptosis relating to epithelial disappearance occurred regularly throughout the palatal region. Migrating bodies that were shed into the oral and nasal cavity were seen regularly, and this appears to be one of the ways of effectively eliminating epithelia.

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We report a case of giant sublingual epidermoid cyst extending bilaterally to the submandibular region because of an anomaly of the digastric muscle. A 29-year-old man was referred to our clinic because of a painless swelling in the left submandibular region. Magnetic resonance imaging revealed a well-defined dumbbell-like mass that extended bilaterally from the sublingual area to the submandibular region. Signal density of the mass was homogeneously intermediate on both T1- and T2-weighted images. The lesion was extraorally extirpated with the patient under general anesthesia. The mass was located inferiorly to the geniohyoid muscle and superiorly to the mylohyoid and digastric muscles. Its central portion was constricted by the aberrant anterior bellies of the digastric muscle. The extirpated mass was an 11.5 ×6.0 ×2.5 cm well-encapsulated cyst containing yellowishbrown paste. It was identified to be an epidermoid cyst on histopathological examination. The postoperative course has been uneventful, without recurrence for about 11 months. Since 1957, 11 cases of giant dermoid or epidermoid cyst more than 5 cm in diameter have been reported in Japan. Our case is the biggest epidermoid cyst so far, and the aberrant shape seemed to be caused by the anomaly of the anterior belly of the digastric muscle.

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Desmoplastic ameloblastoma(DA)is classified as a rare variant of ameloblastoma. Foamy or cellular radiolucency or radiopacity is thought to be characteristic on radiographic examination. We report a case of mandibular DA with unusual radiographic findings. A 60-year-old man was referred to our department in October2004 because of a large growing mass in the left anterior region of the mandible. Radiography and computed tomography revealed a poorly-defined mass with a mixed radiolucent-radiopaque lesion anteriorly and cystic radiolucent areas posteriorly. Histopathological examination of a biopsy specimen suggested that the lesion might comprise two different lesions, with squamous odontogenic tumor anteriorly and inflammatory cyst posteriorly. A treatment plan for extirpation of the lesion followed by curettage of the underlining intact bone under general anesthesia was established, and surgery was performed. The surgical specimen was examined histopathologically, and DA was diagnosed. No signs of local recurrence have been seen as of 3 years after surgery.

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Amyloidosis is caused by amyloid substance deposition in various organs and tissues of the body. A case of systemic amyloidosis with swelling in the tongue and submandibular region as an initial symptom is reported. A 63-year-old man presented with swelling of the tongue and submandibular region. Detailed clinical examinations and biopsy were performed. There were no signs suggesting a malignant tumor. Subsequently, purpura of the lips and induration of the lower lip and buccal mucosa appeared. Chest radiographic examination revealed cardiac hypertrophy and pleural fluid. Systemic amyloidosis was suspected. A biopsy specimen taken from the buccal mucosa revealed deposition of amyloid. Congo-red stain for amyloid was positive. Systemic amyloidosis was diagnosed. The patient was followed up in the department of internal medicine. After 14 months, the patient died of cardiac failure due to amyloid deposition.

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