The use of bisphosphonate (BP) after dental extraction has been reported to cause bisphosphonate-related osteonecrosis of the jaw (BRONJ). Avoidance of oral BP is recommended; however, no guidelines exist for intravenous BP. Therefore, we evaluated the influence of intravenous BP drug holiday (BPdh) on post-extraction healing.
Japanese white rabbits were used. In the sham group, saline was administered intravenously, and the mandibular premolar teeth were extracted; then, the mandible was collected 2-10 weeks after teeth extraction. In the BPdh group, zoledronate was administered intravenously. After 0, 1, 3, and 6 weeks of BPdh, the teeth were extracted. The jaws were collected 6 weeks after the tooth extractions.
The healing status of the extraction socket was assessed. The cancellous bone volume (BV/ TV), trabecular separation (Tb. Sp), and trabecular number (Tb. N) of the mandibular bone lingual side were measured with microfocus X-ray images as healing index.
In the sham group, bone exposure was not observed; BV/ TV 2-10 weeks after tooth extraction decreased from 54.04% to 12.30%; Tb.N decreased from 3.02/mm to 0.83/mm; Tb. Sp increased from 75.10μm to 285.31μm; and bone remodeling on cancellous bone increased at 6 weeks. The results in the sham group at post-extraction 6 weeks, serving as control, were compared with those in the BPdh group.
In the BPdh group, bone was temporarily visible (BRONJ Stage 1) in the 0-3 week groups. Tb.N and BV/ TV in all of the 0-6 week groups were significantly higher than those in the control group; these values were significantly lower in the 6 week group than in the 0 week group. Tb. Sp was significantly higher in the 6 week group than in the 0 week group, but the value was significantly lower in both groups than in the control group.
BP administration resulted in changes in BV/ TV, Tb. N, and Tb. Sp and a delay in the healing process at the extraction site. A possible mechanism might be as follows:(1) BP accumulates in the jaws and is incorporated into osteoclasts; (2) after apoptosis of osteoclasts, BP may reattach to the surface of new trabecular bone in the extraction wound even during BPdh.
The cancellous bone in the 6-week BPdh group was closer to that in the control group than that in the 0 week BPdh group. Healing following tooth extraction in patients who receive intravenous BP therapy may be promoted by BPdh.

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Superficial angiomyxoma is an unusual benign tumor that develops between the dermis and subcutaneous adipose tissue and originates from fibroblasts. We report a case of superficial angiomyxoma in the cheek region. The patient was a 44-year-old man who had noticed a cheek mass 4 years earlier but had not received treatment. The mass grew gradually, and the patient was thus referred to our hospital for surgical treatment. At the first visit, the patient's face appeared asymmetrical because of the nipple-shaped mass in the right cheek region. A biopsy did not provide an accurate pathological diagnosis. With a suspected diagnosis of benign buccal tumor, an operation was performed under general anesthesia. The excised specimen consisted of multiple globular clusters and had a smooth surface. Microscopic examination showed that the mucous component comprised spindle-shaped cells and fibrous tissue containing blood capillaries. Immunohistochemical analysis showed that the tumor cells were positive for CD34 and Factor XIIIa and negative for α-smooth muscle actin and S-100. The MIB-1 index was less than 1%. These results led to a final diagnosis of superficial angiomyxoma. The patient has not shown any sign of tumor recurrence to date (4 years after surgery).

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Hemophilia B is a disease in which the activity of blood coagulation factor IX (Christmas factor) decreases. A 22-year-old man was referred to our clinic by a local dental clinic. The medical and family history were irrelevant to the present disorder. The preoperative APTT value was 38.4 seconds, which was within normal limits. Four wisdom teeth had been extracted under intravenous sedation. On the first postoperative day, slight bleeding was observed from the left side of the upper jaw; this bleeding was controlled using an absorbable topical hemostat. The patient was discharged on the second day after surgery. However, repeated bleeding occurred from the fourth postoperative day, and the patient was re-hospitalized on the seventh day after surgery. The frequency of bleeding decreased gradually, and he was discharged from the hospital 12 days after surgery. The presence of a coagulation abnormality was suspected, and the patient was referred for hematological examination. He was given a diagnosis of hemophilia B based on the finding that the coagulation factor IX activity was reduced to 11%.

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Osteoma is non-odontogenic tumor occurring mainly in the skull and jaw bones. We reported a rare case of recurrent peripheral osteoma of the mandible after a prolonged period.
The patient was a 46-year-old woman with a chief complaint of swelling at the right mandibular angle. Ten years ago, she underwent surgery in another hospital. The operation involved excision of peripheral compact osteoma in the same region. This time, there was a localized hard mass. Computed tomography showed a mass measuring about 24 × 24 × 10 mm. We excised the tumor intraorally under general anesthesia. The histopathological diagnosis was compact osteoma. There has been no sign of local recurrence during a follow-up period of 2 years.

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