The current foundation of preventing nosocomial infection in dental settings are “Guidelines for infection control in dental health-care settings” announced in 2003 by Centers for Disease Control and Prevention (CDC). These guidelines employ a concept of standard precaution in clinical dentistry, and had a great influence on “Guideline for infection control in dental prosthetics” established in 2007 by Japan Prosthodontic Society and “Guideline for infection control in dentistry” announced by the dental division of the infection control conference of the national university hospitals in 2008. On the other hand, there have been many reports about oral care, for instance, ‘1) oral care prevents aspiration-related pneumonia', ‘2) oral care decreases the onset rate of the influenza to a one-tenth, (oral care decreases significantly neuraminidase and protease which bacteria produce) ', ‘3) oral care reduces a side effect in the oral cavity by the chemoradiotherapy', ‘4) oral care prevents ventilator-associated pneumonia in ICU', ‘5) oral care is useful for symptom relief in terminal illness', and an importance of oral care has been widely noticed in late years.
Cases of bisphosphonate-related osteonecrosis of the jaw (BRONJ) have been reported since 2003. Incidence and etiology have been described in many reports since then. So far, it is widely accepted that intravenous administration of bisphosphonates significantly increases the risk of BRONJ in malignant tumor patients. Conversely, relevance of oral bisphosphonates to BRONJ is obscure, because of much lower incidence of BRONJ compared to malignant tumor patients with intravenous administration of bisphosphonates. Etiology of BRONJ is still uncertain, but two major hypotheses have been widely known. One hypothesis is ischemic change of the jaw, which was proposed based on antiangiogenic effects of bisphosphonates. The other well known hypothesis is prevention of remodeling of the jaw bone caused by inhibitory effects of bisphosphonates on osteoclasts. Recently, another new hypothesis for pathogenic mechanism of BRONJ was proposed. In this hypothesis, BRONJ are thought to be induced by delayed wound healing of oral examination caused by toxic effects of bisphosphonates locally released from bone tissue absorbed by inflammatory stimulated osteoclasts at that site. In this review, we also made brief evaluation on pathogenesis of BRONJ using a few histopathological findings of our analyzed BRONJ cases.
Acinic cell carcinoma arising in the palatine salivary glands is relatively rare. We report a case of acinic cell carcinoma arising in the soft palate of a 40-year-old man. The tumor was 10 × 15 mm in size and elastic hard. No swelling of the cervical lymph nodes was palpated. Excision of the tumor was performed with the patient under general anesthesia. Histopathological examination revealed that the parenchyma of the tumor was composed of microcysts. Periodic acid-Schiff (PAS) stain after digestion showed secretory granules in some tumor cells and secretion in dilated lumens. The tumor was diagnosed as a rare atypical case of acinic cell carcinoma showing microcystic and papillary-cystic patterns, characterized by numerous small spaces and prominent cystic spaces, respectively. The postoperative course was uneventful, and there was no evidence of recurrence or metastasis 5 years after surgery.
We describe a case of penetration injury caused by a nail-gun nail that remained in the temporal fossa for about 3 years. A 55-year-old man was referred to our hospital because of a foreign body in the temporal fossa. He had not noticed that there was a foreign body in the temporal fossa after falling down with a nail-gun 3 years previously. Computed tomography confirmed that the foreign body was located in bone. The patient was given local anesthesia, and a long nail was removed. After nail removal, slight bleeding and pyorrhea occurred. However, there was no leakage of spinal fluid. He was discharged 5 days after nail removal. No complications have occurred 6 months after nail removal. In addition, there were no postoperative symptoms.
Oral myxoma usually arises in the jawbone and rarely occurs in soft tissue. A case of myxoma in the gingiva of the upper jaw is reported. The patient was a 75-year-old man, who had noticed a tumor in the right molar gingiva 40 years ago. The tumor became larger after extraction of an upper molar. A mushroom-shaped elastic hard tumor (20 × 20 × 15 mm) was noted in the upper molar gingiva. Radiographic and computed tomographic examinations showed a tumor in the maxilla, but extensive bone resorption was not observed. An incisional biopsy was done, and the diagnosis was myxoma. Partial maxillectomy including the tumor was performed with the patient under general anesthesia. Histopathological examination showed that the tumor was composed of spindle-shaped cells in a myxoid matrix. The tumor was situated mainly in the gingiva, but slight pressure-related bone resorption was observed on the surface of the alveolar bone. Four years after treatment, there was no evidence of recurrence.
We report a case of pyogenic arthritis of the sternoclavicular joint after neck dissection. An 81-year-oldman was referred to our department because of pain in the right sternoclavicular joint on moving the right upper limb in 2007. In 2003, a malignant tumor of the floor of the mouth with bilateral lymph node metastasis was diagnosed. He received preoperative chemotherapy and underwent resection of the malignant tumor in the floor of the mouth, right total neck dissection, and left functional neck dissection. In addition, he received a total of 63 Gy of radiotherapy. After these treatments, there was no sign of tumor recurrence or distant metastasis. However, in June 2007, the patient had pyrexia, tenderness and swelling of the right sternoclavicular joint, and pain in the joint on moving the right upper limb. CT revealed an abscess in the sternoclavicular joint, and pyogenic arthritis of the sternoclavicular joint was diagnosed by an orthopedist. The right sternoclavicular joint was punctured, but the pus could not be removed. He then received antibiotic therapy. Tenderness and swelling of the right sternoclavicular joint disappeared, and pain in the right sternoclavicular joint also resolved. Three months later, the patient visited us again with similar symptoms of the left sternoclavicular joint. Pyogenic arthritis of the left sternoclavicular joint was diagnosed by an orthopedist, and he was given antibiotic therapy again. Subsequently, the symptoms gradually resolved. The patient is being followed up in our outpatient clinic. No recurrence of pyogenic arthritis of the sternoclavicular joint has occurred until now.
The patient was a 41-year-old man presenting with a mass beneath the right buccal mucosa. The mass was soft and regular, with no tenderness. On T1-weighted MRI, the mass showed the same degree of signal intensity as muscle. After administration of Gd-DTPA, the mass showed enhancement. T2-weighted MRI showed slightly higher signal intensity than muscle. The clinical diagnosis was a benign tumor beneath the buccal mucosa. The tumor was removed with the patient under general anesthesia. The histopathological diagnosis was myoepithelioma. Immunohistochemically, KL-1, vimentin, S-100 protein, and CAM5.2 showed positive staining. Glial fibrillary acidic protein, p63, and α-SMA were partially positive. The MIB-1 index was < 5 %. As of 1 year postoperatively, the patient's progress has been good, without recurrence.
Chondroid syringoma is a rare benign subcutaneous tumor that basically resembles pleomorphic adenoma pathologically. It is difficult to diagnose on the basis of only clinical findings. The key points of differential diagnosis are histopathological findings, especially when the tumor contacts the oral mucosa. We describe a 44-year-old woman with a chondroid syringoma in the mental region. On magnetic resonance imaging（MRI）, the tumor appeared as a subcutaneous well-circumscribed area 10 mm in diameter with homogeneous signal intensity. It showed low signal intensity on T1-weighted images and isosignal intensity on T2-weighted images. MRI and intraoperative findings showed that the tumor existed between the skin and the orbicularis oris muscle. Histopathological examination of the resected tumor showed characteristic findings of chondroid syringoma, such as apocrine secretions, branching lumina, and multilayered papillary hyperplasia of the neoplastic epithelium. At the postoperative 1-year follow-up, there was no evidence of recurrence.
A dentigerous cyst associated with a permanent tooth in the jaws is a frequently encountered type of odontogenic cyst, but very rarely arises from a deciduous tooth. We present a case of dentigerous cyst associated with a second upper deciduous molar. The patient was a 2-year-old infant who presented with gingival swelling at a left maxillary molar. The clinical diagnosis was an odontogenic cyst, and marspialization was carried out with the patient under general anesthesia. Histological examination showed that the cyst wall was lined by non-keratining squamous epithelium, with dense proliferation of epithelium cells with abundant vascularization in some areas. There have been no clinical or radiologic signs of recurrence for 5 years after marspialization.