Muammer Urhan

Scintigraphic Evaluation of Osteoblastic Activity in Extraction Sockets Treated With Platelet-Rich Fibrin

PURPOSE To evaluate the effect of platelet-rich fibrin (PRF) on the early bone healing process with bone scintigraphy based on technetium-99m methylene diphosphonate uptake in third molar extraction sockets. PATIENTS AND METHODS Fourteen patients with bilaterally soft tissue impacted third mandibular molars were included in the study. The right and left impacted third molars were surgically extracted in the same session. PRF was randomly administered into one of the extraction sockets, whereas the contralateral sockets were left without treatment. Four weeks after surgery, scintigrams were obtained to evaluate scintigraphic differences between PRF-treated and non-PRF-treated sockets. After completion of the clinical study, PRF samples were evaluated by light and scanning electron microscopy. RESULTS The average increase in technetium-99m methylene diphosphonate uptake as an indication of enhanced bone healing did not differ significantly between PRF-treated and non-PRF-treated sockets 4 weeks postoperatively (P > .05). Abundant fibrin and inflammatory cells were observed by light microscopic examination of PRF samples. Scanning electron microscopic analysis of PRF revealed the existence of platelet aggregates in a fibrin network and crystalline particles on the outer surface of PRF. CONCLUSIONS PRF might not lead to enhanced bone healing in soft tissue impacted mandibular third molar extraction sockets 4 weeks after surgery. PRF exhibits the potential characteristics of an autologous fibrin matrix. However, whether the presence of crystal-like particles on the outer surface of PRF alters bone healing should be investigated further.

The effect of subcutaneous mesenchymal stem cell injection on statis zone and apoptosis in an experimental burn model.

Background: In an acute burn injury the zone of stasis is initially vital but may progress to coagulation necrosis with time. In this study, salvage of the zone of stasis was aimed at by subcutaneous mesenchymal stem cell injection. Methods: Mesenchymal stem cells were obtained from the bone marrow of Sprague-Dawley rats (n = 10). Twenty Sprague-Dawley rats received thermal injury on the back according to the previously described “comb burn” model. Thirty minutes after the burn injury, mesenchymal stem cells were injected subcutaneously to the stasis zone of the experimental group (n = 10). Animals in the control group (n = 10) were given the same amount of saline without mesenchymal stem cells. Animals in the sham group (n = 6) did not receive any thermal trauma. Seventy-two hours after the burn injury, scintigraphic examination was applied to determine average vital tissue at the stasis zone. Thereafter, skin samples were assessed by immunohistochemistry assay for apoptosis count. The blood samples drawn before and 72 hours after the burn injury were analyzed to determine systemic cytokine levels. Results: The apoptosis count of the control group was found to be significantly higher than that of the experimental group. Vital tissue percentage of the stasis zone was significantly higher for the experimental group than for the control group. The cytokine levels did not reveal any statistically significant difference between the groups. Conclusion: Apoptosis count and scintigraphic results of this study confirm that mesenchymal stem cell treatment has a statistically significant benefit for the survival of the stasis zone in acute burn.

Scintigraphic evaluation of early osteoblastic activity in extraction sockets treated with platelet-rich plasma.

PURPOSE The aim of this study was to investigate the early effect of platelet-rich plasma (PRP) on osteoblastic activity during the healing process of soft tissue impacted mandibular third molar extraction sockets by means of bone scintigraphy. PATIENTS AND METHODS Twelve patients with bilaterally soft tissue impacted mandibular third molars were included in the study. The impacted right and left mandibular third molars were surgically extracted in the same session. PRP was administered randomly into the extraction sockets in the study (S) group whereas the extraction sockets in the control (C) group were left without PRP treatment. Scintigrams were obtained in the first and fourth weeks after surgery to evaluate the osteoblastic activity within extraction sockets in both groups. RESULTS Scintigraphic findings of postoperative first and fourth weeks did not show significantly increased osteoblastic activity between S group and C group (P > .05). However, the osteoblastic activity in both groups significantly increased in postoperative week 4 in comparison to week 1 (P < .05). CONCLUSION The application of PRP alone into soft tissue impacted mandibular third molar extraction sockets failed to increase the osteoblastic activity in postsurgical weeks 1 and 4 in comparison to non-PRP-treated sockets.

Scintigraphic, Histologic, and Histomorphometric Analyses of Bovine Bone Mineral and Autogenous Bone Mixture in Sinus Floor Augmentation: A Randomized Controlled Trial—Results After 4 Months of Healing

PURPOSE To test our null hypothesis stating that the mixture of autogenous cortical bone scrapings and bovine bone mineral (BBM) in a ratio of 1:4, compared with BBM alone, would have no significant effect on new bone formation 4 months after maxillary sinus floor augmentation. PATIENTS AND METHODS Twenty-four patients presenting with alveolar bone height of less than 5 mm in the narrowest zone between the sinus floor and alveolar crest were randomly assigned to 2 treatment groups in this randomized controlled trial. We augmented 12 maxillary sinuses with a mixture of BBM and cortical autogenous bone graft, which was collected from the lateral wall of the maxillary sinus by a bone scraper, and 12 maxillary sinuses with BBM alone. Four months postoperatively, new bone formation in the augmented sinus sites was evaluated through bone scintigraphy, as well as histologic and histomorphometric analyses of the biopsy specimens obtained during implant placement. Data were statistically analyzed by independent-samples t test. RESULTS Scintigraphically detectable new bone formation did not differ significantly between the groups (P > .05). Histologic findings showed that the new bone bridged between BBM particles and BBM underwent resorption by osteoclasts with or without the addition of autogenous bone graft. According to histomorphometric findings, the difference between the percentages of newly formed bone in the sinuses augmented with graft mixture (25.73%) and BBM alone (24.19%) was statistically nonsignificant (P > .05). CONCLUSIONS The addition of autogenous cortical bone scrapings to BBM in a ratio of 1:4, compared with BBM alone, does not markedly increase new bone formation 4 months after maxillary sinus lifting.

Salvaging the zone of stasis by simvastatin: an experimental study in rats.

Salvaging the zone of stasis is important for burn researchers because this can prevent an increase in the depth and width of the injured area. Statin analogues have many pleiotropic effects on the vessel walls and the coagulation and fibrinolytic systems. In this study, we investigated the effects of simvastatin, a statin analogue, administered to rats burned with a metal comb. No treatment was given to the control group (n = 10). Simvastatin was given at a dose of 5 mg/kg/d by intraperitoneal injection in treatment group (n = 10) for 7 days. Phosphate-buffered saline was given 1 mg/kg/d by intraperitoneal injection in sham group (n = 10). The groups were randomly divided into two subgroups (n = 5) for evaluation at 24 hours and 7 days. It was observed that there were necrotic areas and viable interspaces in both the experimental and control groups at 24 hours. The interspaces progressed to necrotic areas in the control and sham groups at 7 days. However, viable interspaces were separated from necrotic areas clearly in the treatment group at 7 days. In the samples taken from interspaces at 24 hours, positive staining for thrombomodulin (TM) for all groups was noted. In the samples taken from the control and phosphate-buffered saline groups at 7 days, there was negative staining for TM. However, in the samples taken from interspaces of the treatment group, positive staining for TM was observed. The conclusion of this study was that simvastatin potently increased endothelial TM expression in the zone of stasis and preserved the zone.

FDG PET/CT appearance of multicentric Castleman's disease mimicking lymphoma

We report a case of a multicentric form of Castlemans disease with multiple lymph nodes showing intense FDG uptake on whole body scan mimicking non-Hodgkins lymphoma. In this report, the patient had multiple cervical, mediastinal, hilar, retroperitoneal and abnormal lymph nodes in the groin. (18)F-fluorodeoxyglucose positron emission tomography/computed tomography was performed before tissue sampling. (18)F-FDG/PET demonstrated multiple areas of increased uptake in cervical, mediastinal, hilar, retroperitoneal and groin lymph nodes, suggesting a generalized disease of the lymphatic system including non-Hodgkins lymphoma. The final diagnosis is based on the histopathological findings of the material obtained from the cervical lymphadenectomy. The histological diagnosis was multicentric plasma cell variant of Castlemans disease. (18)F fluorodeoxyglucose positron emission tomography/computed tomography scan helped to identify the lymph nodes involved throughout the whole body, but did not help to differentiate non-Hodgkins lymphoma. The clinical conclusions and PET/CT findings are described in this report.

Effect of hyperbaric oxygen therapy on bone prefabrication in rats

OBJECTIVES This experimental study aimed to create a prefabricated vascularized bone graft using the interconnected porous coralline hydroxyapatite ceramic by combining vascular bundle implantation, mesenchymal stem cells, and hyperbaric oxygen therapy (HBOT) administration in a rat model. METHODS Forty-five male Sprague-Dawley rats were divided into three groups, each containing 15 rats. The hydroxyapatite ceramics were vascularized by the superficial inferior epigastric artery and vein in all groups. These vessels passed through the hole of the hydroxyapatite blocks. In Group 2, mesenchymal stem cells were administered into the hydroxyapatite. In Group 3, both mesenchymal stem cells and HBOT were administered. The presence and density of any new bone formation and neovascularization were evaluated by radiography, microangiography, scintigraphy, biochemical analysis, and histomorphometry. RESULTS Neovascularization and bone formation were significantly greater in Group 3, in which both mesenchymal stem cells and HBOT were applied, than the other groups. CONCLUSION HBOT enhances neovascularization and osteogenesis, thus HBOT can provide optimal and faster prefabrication of a vascularized bone graft.

Prefabrication of vascularized bone graft using an interconnected porous calcium hydroxyapatite ceramic in presence of vascular endothelial growth factor and bone marrow mesenchymal stem cells: Experimental study in rats

Objectives: The purpose of this experimental pilot study was to create a prefabricated vascularized bone graft using interconnected porous calcium hydroxyapatite ceramic (PCHC) block by combining vascular bundle implantation, rat bone marrow mesenchymal stem cells and administration of vascular endothelial growth factor (VEGF) in a rat model. Materials and Methods: Sixty male Sprague-Dawley rats were used. Experimental animals were divided into six groups, each of which comprised 10 rats. The PCHC blocks were implanted in the medial thigh region in groups I, III, and V without vascular bundle implantation. The PCHC blocks were vascularized by the superficial inferior epigastric artery and vein in groups II, IV and VI. These vessels were passed through the hole of the PCHC blocks. Mesenchymal stem cells were administered into the PCHC in groups III, IV, V and VI. In addition, both mesenchymal stem cells and VEGF were administered in group V and VI. The presence and density of any new bone formation and neovascularization from the vascular bundle was evaluated by X-ray, microangiography, scintigraphy, biochemical analysis and histomorphometry. Results: The newly formed vessels and bone formations were significantly greater in group VI, in which both mesenchymal stem cells and VEGF were applied. Conclusion: This preliminary study suggests that: Both mesenchymal stem cells and VEGF provide vascularized bone prefabrication by enhancing neovascularization and osteogenesis in a shorter time compared to only VEGF application.

Malignant melanoma and papillary thyroid carcinoma that were diagnosed concurrently and treated simultaneously: A case report

Malignant melanoma can be successfully treated when it is identified in its early stages, but the disease is associated with a poor prognosis when it is detected in an advanced stage. Papillary thyroid carcinoma is a thyroid cancer that has a good prognosis. The present study reports a rare case of malignant melanoma and papillary thyroid carcinoma that were diagnosed concurrently and treated simultaneously. The present patient was a 37-year-old male, in whom examination of a skin biopsy that was obtained from a lesion in the right retroauricular region revealed the lesion to be consistent with malignant melanoma. The patient underwent radical neck dissection upon the detection of malignant melanoma metastasis to the sentinel lymph node. Metastases of papillary thyroid carcinoma were detected in four out of 38 lymph nodes. The patient was then diagnosed with papillary thyroid carcinoma and underwent total thyroidectomy. The patient was administered with high-dose followed by moderate-dose interferon-α therapy for the treatment of malignant melanoma. The patient also received concurrent radioactive iodine therapy for the treatment of papillary thyroid carcinoma, at the same time as the interferon therapy. The two primary tumors of the patient were treated successfully. During therapy, no serious side-effects were observed, with the exception of fever caused by high-dose interferon therapy. Malignant melanoma and papillary thyroid carcinoma may occur concurrently, although this is rarely observed. The present study reports a rare case that demonstrates that the two tumors can be successfully treated simultaneously.

One-and-a-half-barrel vascularized free fibular flap for the reconstruction of segmental mandibular defect.

We designed one-and-a-half-barrel vascularized free fibular flap which is a further modification of the double-barrel technique, and we tried to overcome the discrepancy between mandible and fibula flap. We used this flap in case of a segmental mandibular defect that occurred as a result of a giant cell reparative granuloma excision. This new modification eliminated volume insufficiency of the classical technique and volume excess of the double-barrel technique.A segmental mandibular defect that occurred as a result of giant cell reparative granuloma excision was reconstructed using one-and-a-half-barrel vascularized free fibular flap. The size discrepancy between mandible and free fibula flap is a well-known problem, and this new modification of free fibular flap eliminated volume insufficiency or excess problems of the other techniques.