Göran Kjeller

Surgical treatment of recurring ameloblastoma, are there options?

Our aim was to evaluate the treatment given to patients with intraosseus ameloblastomas with special emphasis on recurrence and the outcomes of primary and secondary resection. Forty-eight patients who were treated for intraosseous ameloblastoma at 8 centres across Sweden met the inclusion criteria. They showed typical distribution of age, sex, site of lesion, and characteristic presenting features. Eleven of the 48 were initially treated with radical resection and none recurred. Twenty-two of the remaining 37 who were initially treated by conservative resection presented with recurrences. Sixteen of the 22 then had conservative secondary resections, which resulted in further recurrence in 6 patients. Initial radical resection is therefore superior to conservative management as far as recurrences are concerned. We argue, however, that a conservative surgical approach is adequate for many intraosseous ameloblastomas with limited extension, because relapse can be followed by radical resection if clinically indicated in selected cases.

Correlation of Platelet Growth Factor Release in Jawbone Defect Repair : A Study in the Dog Mandible

BACKGROUND Platelet concentrate/platelet-rich plasma (PRP) has been studied extensively in various experimental models and there is some agreement among workers to its early effect in bone regeneration and healing. We have earlier showed in vitro that titanium in whole blood activates the thrombogenic response to a higher degree than PRP and that a fluoridated test surface augmented the effect compared with control. PURPOSE We designed this study to evaluate the effect of PRP and whole blood on bone regeneration in a dog implant defect model and, in addition, the effect of a test surface modified in hydrofluoric acid. A correlation attempt between platelet count, release of growth factors, and bone regeneration was made. MATERIALS AND METHODS Six dogs were used and simultaneously with the experimental surgery and implant installation, autologous PRP was prepared. Defects were prepared (6 mm in diameter and 5 mm deep), and implants were installed (TiO2 gritblasted and hydrofluoric acid treated [test] or TiO2 gritblasted [control], 5 mm in diameter and 9 mm long) in defects filled with either PRP or whole blood. Randomization of sides between PRP and whole blood, and sites for test and control implants were made. Blood samples were collected from PRP and whole blood. The dogs were killed after 5 weeks of healing, and samples with implants and surrounding bone were collected and processed for analysis. Enzyme linked immunosorbent assays were used for detection of growth factors in PRP. RESULTS The mean increase of platelet count was 424% in PRP. A correlation for platelet counts and transforming growth factor β was found in each dog (r(2) = 0.857). Approximately 50% of the region of interest (ROI) in the defects was filled with new bone after 5 weeks. No difference could be observed in ROI by using PRP or whole blood in the defects regarding new bone formation, bone in contact with implant, or distance to first bone contact. However, the fluoridated implants exhibited more new bone formation (p = .03) compared with control, regardless of comparing PRP or whole blood, and also displayed a shorter distance from first bone contact to the margin of the bone envelope (p = .05). CONCLUSIONS Platelet concentrate/PRP failed to show more new bone regeneration in a peri-implant defect model compared with whole blood. Implants treated with hydrofluoric acid displayed higher percentages of bone fill in the defect.

Electron Beam Melting Manufacturing Technology for Individually Manufactured Jaw Prosthesis: A Case Report

In the field of maxillofacial reconstruction, additive manufacturing technologies, specifically electron beam melting (EBM), offer clinicians the potential for patient-customized design of jaw prostheses, which match both load-bearing and esthetic demands. The technique allows an innovative, functional design, combining integrated porous regions for bone ingrowth and secondary biological fixation with solid load-bearing regions ensuring the biomechanical performance. A patient-specific mandibular prosthesis manufactured using EBM was successfully used to reconstruct a patients mandibular defect after en bloc resection. Over a 9-month follow-up period, the patient had no complications. A short operating time, good esthetic outcome, and high level of patient satisfaction as measured by quality-of-life questionnaires-the European Organisation for Research and Treatment of Cancer QLQ-C30 (30-item quality-of-life core questionnaire) and H&N35 (head and neck cancer module)-were reported for this case. Individually planned and designed EBM-produced prostheses may be suggested as a possible future alternative to fibular grafts or other reconstructive methods. However, the role of porosity, the role of geometry, and the optimal combination of solid and porous parts, as well as surface properties in relation to soft tissues, should be carefully evaluated in long-term clinical trials.

Increase of Compact Bone Thickness in Rat Tibia after Implanting MgO into the Bone Marrow Cavity

The effect of implanting MgO paste into the bone marrow of rat tibia, was studied by light microscopy, time of flight-secondary ion mass spectrometry (ToF-SIMS), and environmental scanning electron microscopy (ESEM), and energy dispersive X-ray (EDX) analysis. After three weeks of implantation, the thickness of compact bone increased by 25% compared to sham-operated controls, while no effect was seen on the trabecular bone. In order to further elucidate the mechanism of the Mg-induced increase in bone mass, EDX and ToF-SIMS analysis of the bone samples was made at two weeks. At this time-point, no detectable difference in the thickness of the compact bone in Mg-treated and non-treated animals was observed. The Mg-content of the bone marrow and bone tissue of the Mg-exposed animals did not differ from that of sham-operated controls, implying that there are no traces of the implanted MgO when the mass of compact bone increases, between two and three weeks after surgery. The ratio of Mg/Ca content was higher in the bone of Mg-treated animals, indicating an altered structure of the bone mineral, which was confirmed by the ToF-SIMS analysis, showing increased levels of MgCO3, phosphate ions and CaF in the bone of MgO-exposed animals. Possible cellular activities behind the effect of MgO on compact bone thickness are discussed.

Potentially Malignant Oral Disorders and Cancer Transformation

Cancer in the oral cavity is often preceded by precursor lesions. Nine oral mucosal disorders are known to have an increased risk of malignant transformation. The etiology varies from disorders caused by exogenous factors such as tobacco and autoimmune inflammation to idiopathic or inherited genetic aberrations. In this review, these potentially malignant disorders (PMDs) are described regarding clinical presentation and histopathological architecture. Special attention is paid to the underlying etiologies of PMDs and the potential pathways leading to cancer. The clinical perspective focuses on the importance of accurate and timely diagnosis.

Medication related osteonecrosis of the jaw (MRONJ): Computer assisted assessment of pathological skeletal changes

Study design: Prospective, randomized study. 50 patients aged less than 12 years who are going to have operations with expected blood loss, more than 10% of total blood volume (TBV) were included. Exclusion criteria were any patient with respiratory, hepatic or renal dysfunction, haemato-oncological disorders and abdominal surgery due lack of appropriate probe. Operational course was categorized into two stages, stage I in which expected blood loss was ≤10% of TBV and the allowed fluid transfusion was only the maintenance transfusion and stage II, in which the expected blood loss was >10% of TBV and the patient was given replacement transfusion with either crystalloids, colloids or blood products at the direction of anesthesia provider. Heart rate, noninvasive blood pressure was contentiously monitored. Maximum and minimum IVC diameter (IVCmax, IVCmin) and collapsibility index were measured before, immediately after induction and at least every 15 minutes according to the degree of blood loss. Central venous line was inserted after induction of anesthesia and CVP was measured every at least 15 minutes according to blood loss.

Computer assisted assessment of progressing osteoradionecrosis of the jaw for clinical diagnosis and treatment

Abstract Osteoradionecrosis (ORN) is a serious side effect of oncologic radiation therapy. Often, surgical removal of the affected skeletal tissue is indicated. In cranio-maxillofacial surgery, partial or total resection of the upper or lower jaw implies a severe impairment of the patient‘s quality of life. Up to now, clear display of ORN is still a challenge. This part of the project is dedicated to medical visualization of progressing ORN for clinical diagnosis. Currently, clinical diagnosis of ORN is mostly based on computer tomography (CT). With regard to its high advantages as e.g. reduced radiation dose, we additionally evaluate cone beam computer tomography (CBCT). After registration on a suitable reference and refined image processing and segmentation, all patient’s CT-/CBCT-data are subjected to various rendering techniques configured for the respective purpose, namely visualization of destructive and/or sclerotic skeletal alterations, consideration of cortical or trabecular bone, and analysis based on CT or CBCT. Recent achievements within the project were demonstrated with special focus on evaluation of both, CT and CBCT as well as on close cooperation with the clinical setting.