In this presentation, indications of dental implant were discussed with reconsiderations. Clinical indications are now maintained as a missing of tooth, combination of tooth and bone loss by trauma injuries, maxillomandibular defect following oral cancer abration, cleft lip and palate, congenital disorders with delayed eruption or impacted tooth such as ectodermal dysplasia, jaw deformities, and orthodontic applications. For these situations, prosthetic surgeries such as alveolar plasty using mucosa and dermal grafts, onlay or inner grafts by autogenous bone, GBR (guided bone regeneration) technique, decortication, split crest and splitting alveolar osteoplasty, sinus lift and socket lift procedure, alveolar nerve transposition, vertical and horizontal distraction osteogenesis, and PRP (platelet-rich plasma) graftings has employed before or at the same time of dental implant placement. The problems of indication of implant contains age, anatomical reasons, and systemic complications. Placed dental implant, produced in titanium, should be carefully observed on the point of allergic reaction and carcinogenesis for a long time.

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Oral biofilm-forming bacteria consist of a dense bacterial mass tightly adhering to the surface of the oral cavity. The characteristics of dental biofilm are resistant against not only host defense mechanisms but also various antimicrobial agents. The predominant bacteria forming biofilm result in persistent infection. The proteolytic enzymes, exotoxins, endotoxins, and HSPs of these bacteria play a significant role in the development of oral infectious disease and affect systemic condition.
We detected DNA and antigen of Treponema denticola in atherosclerotic lesions, and also found that the 16S rRNAs of Porphyromonas gingivalis, Aggregatibacter (formally Actinobacillus) actinomycetemcomitans,Tannerella forsythia, T. denticola, and Campylobacter rectus in samples of stenotic coronary arterial plaque. We showed the invasive activity of these bacteria into human vein endothelial cells. Increasing evidence has linked the dental biofilm with respiratory infectious diseases such as aspiration pneumonia in elderly persons. We investigated the effects of oral health care for elderly persons requiring nursing care on prevention of influenza infection.In the oral care group, colony-forming cell number, neuraminidase and trypsin-like protease activities in saliva decreased. It was found that one of 98 patients was diagnosed with influenza; whereas, in the non-oral care group,nine of 92 patients were diagnosed with influenza. The finding indicates that oral hygiene is one of the effective strategies to prevent influenza infection. Periodontal surrounding cells such as macrophage possessing TLRs and CD14 that are endotoxin binding protein. Carrying endotoxin with macrophage to various tissues releases inflammatory cytokines such as TNF-αand IL-1 that produce resistance to insulin sensitivity and cause obesity and diabetes. An attempt to discover new things by studying the past through scrutiny of old, there are many evidences on the close relationship between the primary dental biofilm infectious diseases and secondly systemic diseases such as nephritis, dermatitis and arthritis.
The author firmly believes that control of oral biofilm-forming infectious diseases by the surgical treatment is an essential strategy and management of such systemic conditions.

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Periodontal disease as a biofilm infectious disease is considered. Periodontal disease-associated bacteria formed biofilm in periodontal pockets or on the surface of cementum. Planktonic bacteria from biofilm invade into periodontal tissues and lead to inflammation and destruction of tissues directly and indirectly by elicit host defense mechanism. Supragingival dental plaques (biofilm) are easily removed by professional mechanical tooth cleaning, while subgingival dental plaques and bacteria invading into periodontal tissues are difficult to be removed. Therefore, the development of novel methods for periodontal disease is needed to eliminate these biofilms efficiently. Hereby, we report the effect of antibiotics on in vitro biofilm model of periodontal disease and the systemic administration of azithromycin for the early-onset (aggressive) periodontitis.

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The number of patients with osteomyelitis of the mandible has decreased in recent years because of early diagnosis and aggressive treatment with antibiotics. However, refractory chronic osteomyelitis of the mandible remains a problem. Only a few reports have systematically discussed the treatment of chronic osteomyelitis of the mandible, and there is no standard treatment. In addition, although the closed irrigation-suction method has been used in the field of orthopedics as an adjunctive therapy for osteomyelitis, only a few studies have used this method in oral and maxillofacial surgery. This report is based on 26 patients with chronic osteomyelitis of the mandible who received closed irrigation-suction treatment after surgery. Recurrence after treatment occurred in only 2 patients(7.7 %)followed up for up to 12 years. This report describes the details of the closed irrigation-suction treatment and discusses its advantages.

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Pleomorphic adenoma is the most frequent benign tumor arising in the major salivary glands.Histopathological findings of this tumor vary; however, extensive necrosis does not generally occur. We describe a 74-year-old woman with pleomorphic adenoma of the submandibular gland associated with extensive degenerative necrosis. She consulted our hospital because of a painless swelling that had persisted for 20 years in the right submandibular region. MRI revealed a mass with a distinct border in the right submandibular gland, associated with a low-signal-intensity area. The patient was given a diagnosis of pleomorphic adenoma of the right submandibular gland, and tumorectomy was performed under general anesthesia.
Histopathological examination of the resected specimen showed a pleomorphic adenoma with extensive necrosis. During the 5-year postoperative follow-up, there has been no recurrence.
Pleomorphic adenoma of the major salivary glands with extensive degenerative necrosis is very rare. Only 9 cases of this type of adenoma in the parotid gland have been reported. To our knowledge, this is the first such tumor arising in the submandibular gland to be reported.

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This report describes the feasibility of posterior-superior repositioning of the maxilla by Le Fort Ⅰ osteotomy with a pterygoid process fracture, while preserving the descending palatine artery. We examined movement accuracy and stability in 3 patients in whom maxillary protrusion with vertical maxillary excess was treated by moving the maxilla backward more than 4 mm. The postsurgical positions of the maxilla were more posterior than the presurgical expectations, but the differences were within 1 mm. Cephalometric analysis revealed that the differences in each measurement between immediately and one year after surgery were within 1 degree. Without mandibular osteotomy, maxillary protrusion can be satisfactorily treated with Le Fort Ⅰ osteotomy alone.

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Methotrexate (MTX) has been widely used to treat rheumatoid arthritis. Recently, however, several studies have suggested an increased risk of malignant lymphoma in patients treated with MTX. We report such a case of MTX-associated lymphoproliferative disorder (MTX-LPD) that was diagnosed on detection of ulceration of the tongue. A 70-year-old woman was referred to our clinic because of severe pain with associated a unilateral ulcer on the left side of the tongue. The lesion appeared similar to a giant aphtha, but was not surrounded by induration. Microscopic examination of a biopsy specimen demonstrated a lymphocytic infiltrate with increasingly atypical histopathological features. The atypical cells were positive for CD20, EBER-ISH, and LMP-1. The patient had a history of rheumatoid arthritis diagnosed 14 years previously, and administration of low-dose MTX (8 mg/weekly) had been started 17 months before presentation. Based on the medical history and results of histopathological examination, a final diagnosis of MTX-LPD was made. The lesion responded well to the withdrawal of MTX, followed by chemotherapy (R-CHOP). There have been no signs of recurrence for 23 months since the withdrawal of MTX. Because of the increased risk of lymphoid malignancy, oral lesions should be carefully observed in patients with rheumatoid arthritis who receive low-dose MTX.

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We describe our experienced with a case of acute encephalopathy fugax associated with intra-arterial infusion chemotherapy for tongue cancer, which seemed to be reversible posterior leukoencephalopathy possibly related to cisplatin. A 58-year-old man was treated by intra-arterial infusion chemotherapy with cisplatin plus oral TS-1 for tongue cancer. Immediately after the 10th intra-arterial injection of cisplatin, the patient had acute encephalopathy associated with right motor paralysis of the right limbs, aphasia, disorientation, cortical blindness,and tonic convulsions. The next day, all symptoms improved. It is rare that acute encephalopathy occurs, but the risk should be considered in patients given chemotherapy.

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We report a rare case of congenital lateral fistula of the upper lip associated with choanal atresia and nasal deformation. The characteristic clinical features of this case were a fistula located on the philtrum ridge at the columella base, associated with nasal deformation and choanal atresia. At 2 months of age, fistulectomy was performed with rhino-cheiloplasty under general anesthesia. Histological examination revealed that the resected fistula was lined by stratified squamous epithelium with sebaceous glands, which were not observed in deep sections of the fistula, and hair follicles.

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