Sinus floor elevation with platelet-rich fibrin alone: A Clinical retrospective study of 1-7 years.

BACKGROUND: Several sinus floor elevation procedures for implant placement have been introduced. The present study aimed to evaluate the implants placed with Platelet-rich fibrin (PRF) alone in atrophic posterior maxillae and survival rates and the potential factors associated with implant loss. MATERIAL AND METHODS: This retrospective study evaluated 71 implants in 34 patients after 1-7 years' follow-up time. Statistical models were used to determine the implant survival and the potential factors associated with loss. RESULTS: Overall, 7 implants were lost, and the cumulative survival rate at 7 years by implant-based and patient-bases analyses were 85.5% and 85.7%, respectively. The mean residual bone height (RBH) was 4.26 mm. The implant survival rate was significantly lower at RBH < 4 mm than RBH ≥ 4 mm. CONCLUSIONS: This retrospective study showed that sinus floor elevation with PRF alone could be applied in cases of lower RBH. However, it should be carefully performed in cases of RBH < 4 mm before surgery. Key words:Platelet-rich fibrin, dental implant, sinus augmentation, retrospective study.

Sinus Augmentation by Platelet-Rich Fibrin Alone: A Report of Two Cases with Histological Examinations.

In sinus floor augmentation of an atrophic posterior maxilla, platelet-rich fibrin (PRF) has been used as a graft material. We herein report two cases with histological evaluations of PRF after the surgery. The first case was a 28-year-old female with an atrophic right posterior maxilla who was treated with sinus floor augmentation and simultaneous implant placement using PRF as the sole graft material in our hospital. Twenty-four months after surgery, the implant was unfortunately removed because of occlusal overloading by parafunctional habits. During implant replacement, a tissue sample was obtained from the site of augmentation with PRF and was evaluated histologically. The second case was a 58-year-old man with severe alveolar atrophy of the right maxilla who underwent lateral sinus augmentation using only PRF in a two-stage procedure in our hospital. Samples were obtained at the second-stage surgery and histological examinations were performed. As a result, new bone formation was confirmed histologically in both cases. Our findings show that the use of PRF as a graft material during sinus floor augmentation induces natural bone regeneration.

Treatment and prognosis of malignant melanoma of the oral cavity: preoperative surgical procedure increases risk of distant metastasis.

OBJECTIVE: Many authors have reported that oral melanoma patients showed much worse prognosis than those with cutaneous melanoma. We investigated treatment method and prognosis of patients with oral malignant melanoma. STUDY DESIGN: Twenty-one patients with oral melanoma treated at our hospital were investigated, with special reference to the influence of preoperative surgical procedures such as biopsy, incision, or tooth extraction on the prognosis. RESULTS: All patients underwent surgery followed by immuno-chemotherapy with dimethyl triazeno imidazole carboxamide (DTIC), ninustine hydrochloride (ACNU), vincristine (VCR), and biologic response modifier OK-432. Local control was obtained in 20 of 21 patients. Lymph node metastasis appeared in 13 patients, but neck failure was not detected in any patients. Distant metastasis occurred in 9 patients in spite of loco-regional control. Five-year survival rate of 12 patients with no preoperative surgical procedure was 91.7%, while that of the 9 patients who had undergone surgical procedures before treatment was 25.9% (P < .05). CONCLUSIONS: Oral melanoma patients can obtain a prognosis as good as that for cutaneous melanoma patients, when the above-mentioned therapy is used without any preoperative surgical procedures.

Detection of cancer cells in the peripheral blood and lung of mice after transplantation of human adenoid cystic carcinoma.

Polymerase chain reaction (PCR) targeting human beta-globin gene has been reported to be able to detect micrometastasis in an animal model. We attempted to detect cancer cells from the lung and peripheral blood in nude mice, into which a human adenoid cystic carcinoma (ACC) line (KOA-1 and KOA-1L3) had been transplanted. Positive PCR reaction was observed in the lung of a total of 19 of 47 (40.4%) mice into which KOA-1 tumor cells had been transplanted: none of 10 after 1 month, seven of 18 after 2 months, and 12 of 19 after 3 months or later. The KOA-1L3 tumor showed earlier lung metastasis, that is, two of 24 after 7 days and two of 12 after 14 days. Positive PCR reaction was confirmed in the blood samples of three of 19 mice. The lungs of these mice were positive PCR results after subcutaneous transplantation of the KOA-1 tumor. Three of four mice in these blood samples were confirmed in Positive PCR reaction after subcutaneous transplantation of the KOA-1L3 tumor similarly. The lungs of these mice were PCR positive reaction as well as the lungs of transplantation KOA-1 tumor mice. On the other hand, negative PCR reaction was showed these lungs of 60 mice after subcutaneous transplantation of the KOA-1 or KOA-1L3 tumor. All of them were showed negative PCR results in the blood samples. This experimental model can be expected to provide a more detailed understanding of ACC, as well as help to develop a therapy for metastasis of ACC.

En bloc resection of the primary tumour and cervical lymph nodes through the parapharyngeal space in patients with squamous cell carcinoma of the maxilla: a preliminary study.

We retrospectively studied 72 patients with maxillary carcinoma (48 of the gingiva, 22 of the antrum, and one each of the hard palate and maxillary bone). The 5-year survival was 73% for those with gingival carcinoma, and 45% for those with antral carcinoma. Nine patients died of local recurrence, three of cervical metastases, six of distant metastases, and five died of metastases in lateral retropharyngeal nodes despite successful control of local and regional disease. We have recently done en bloc resections of the maxilla and cervical lymph nodes through the parapharyngeal space for patients with posteriorly invasive maxillary cancer accompanied by lymph node metastases in the upper jugular region.

Establishment and characterization of metastasizing cell lines from a heterotransplanted human adenoid cystic carcinoma.

Adenoid cystic carcinoma (ACC) is a rare malignant tumor of the head and neck occurring in the salivary glands. We established a human ACC line which is serially transplantable in nude mice and designated it as KOA-1. The KOA-1 tumor doubled in 9.3 days and retained the histologic characteristics of a solid pattern of ACC even after 22 serial passages. The KOA-1 metastasized to the lung 2 months after subcutaneous transplantation into nude mice. We further established a subline of KOA-1 by an in vivo selection method and named it KOA-1L3. The KOA-1L3 doubled in 1.3 days and metastasized to the lung within 1 week after subcutaneous transplantation. These tumor lines may serve as a useful model for exploration of the biological behavior and treatment of human ACC.

Lack of survival advantage in patients with advanced, resectable squamous cell carcinoma of the oral cavity receiving induction chemotherapy with cisplatin (CDDP), docetaxel (TXT) and 5-fluorouracil (5FU).

Cisplatin-based neoadjuvant chemotherapy (NAC) has been reported to increase survival of patients with nasopharyngeal carcinoma, and organ preservation in those with laryngeal carcinoma, but its efficacy for other head and neck carcinomas is still controversial. We examined the effects of NAC for patients with stage III-IV squamous cell carcinoma of the oral cavity. The patients were divided into two groups; 9 patients who underwent NAC consisting of one course of cisplatin (CDDP), docetaxel (TXT) and 5-fluorouracil (5FU) followed by surgery (NAC group), and 18 patients who underwent surgery alone (control group). Complete response (CR) was not observed, but partial response (PR) was obtained in 6 of 9 patients (33%) of the NAC group. The 3-year survival rate was 29.6% in the NAC group and 81.5% in the control group. Although any valid conclusions could not be drawn because of the small number of patients examined here, NAC with CDDP, TXT and 5FU offered no advantages over standard treatment for advanced oral cancer in terms of survival.