Reimplantation of cultivated human bone cells from the posterior maxilla for sinus floor augmentation. Histological results from a randomized controlled clinical trial.

OBJECTIVES: The aim of the present randomized clinical study was to evaluate histologically whether the addition of cultivated, autogenous bone cells to a composite graft of deproteinized bovine bone mineral (DBBM) and autogenous bone (AB) for sinus floor augmentation (SFA) enhance bone formation compared with what achieved after SFA with DBBM + AB alone. MATERIAL AND METHODS: Twenty patients with remaining posterior maxillary alveolar crest height of less than 3 mm received SFA after randomization either with an DBBM and AB composite in a 1 : 1 ratio or with DBBM + AB supplemented with autogenous bone cells, which were cultivated from a bone biopsy harvested earlier from the tuberosity area. Four months after SFA, two cylindrical biopsies were taken from the augmented sinuses concomitantly with the implant site preparation by means of a trephine bur. An additional biopsy was taken from the tuberosity area. Bone density at the augmented sinus and the tuberosity area and the height of augmentation were estimated on non-decalcified histological sections prepared from the biopsies. A relative bone density index (RBD) was also calculated by dividing bone density at the augmented sinus with bone density at the tuberosity area. RESULTS: All patients but one could receive two implants after SFA; in one patient, only one implant could be placed. All implants were osseointegrated and could be loaded. Median bone density in the sinus was 30% and 25% in the cell seeded and no-cells added DBBM + AB groups, respectively. Bone augmentation height averaged 6.0 and 5.4 mm and RBD averaged 0.48 and 0.73 in the cell seeded and no-cells added DBBM + AB groups, respectively. None of the differences between groups was statistically significant. CONCLUSIONS: Cultivated autogenous bone cell seeded to a DBBM + AB composite did not significantly improve bone formation (density and height) after SFA, compared with what was achieved with DBBM + AB alone. Both approaches resulted into enough bone to support implant placement and osseointegration.

Homologous activated platelets stimulate differentiation and proliferation of primary human bone cells.

In bone tissue engineering approaches the expansion of bone cells is an essential part. In recent years the search for an appropriate alternative to fetal bovine serum (FBS) in the ex vivo expansion process has increased. This study demonstrates that platelet-rich clot releasate (PRCR) could be an appropriate alternative. The effects of PRCR on bone cell cultures derived from 5 different human donors were analyzed with respect to morphology, proliferation, apoptosis and gene expression. Five different PRCR concentrations were used: 1, 5, 10, 20 and 40%. The population doubling (PD) values were calculated for each concentration. Light microscopy analysis was done after 3 and 9 days. Flow cytometry was used to analyze cell cycle effects. The gene expression of alkaline phosphatase, collagen type 1, osteocalcin, bone sialoprotein and osteopontin was analyzed with RT-PCR. 10% FBS cultures were used as controls. With 10% PRCR the cell morphology resembled the control cultures; however, the PD values were significantly higher (p < 0.01). Concentrations of 20 and 40% had a clear cytotoxic effect, observed with light microscopy analysis and flow cytometry. PRCR had a potent effect on the expression of osteogenic markers and resulted in a concentration-dependent upregulation. We demonstrate that human bone cells derived from the maxillary alveolar ridge can be cultured in medium containing PRCR instead of FBS. The addition of PRCR results in higher proliferative capacity and upregulation of osteogenic markers. These results indicate that FBS could be avoided in future tissue engineering approaches using bone cells from this anatomic site.

Immediate postoperative outcome of orthognathic surgical planning, and prediction of positional changes in hard and soft tissue, independently of the extent and direction of the surgical corrections required.

Our purpose was to evaluate the immediate postoperative outcome of preoperatively planned and predicted positional changes in hard and soft tissue in 100 prospectively and consecutively planned and treated patients; all had various dentofacial deformities that required single or double jaw orthognathic correction using the computerised, cephalometric, orthognathic, surgical planning system (TIOPS). Preoperative cephalograms were analysed and treatment plans and prediction tracings produced by computerised interactive simulation. The planned changes were transferred to models and finally to operation. Five to 6 weeks postoperatively, the changes in profile actually obtained in the hard and soft tissue were cephalometrically assessed. The mean accuracy was relatively high. At the cephalometric reference points where significant differences between planned or predicted, and actually obtained, positional changes in hard and soft tissue were apparent and the inaccuracies were, except for the predicted horizontal position of the lower lip, relatively small. However, the variability of the predicted outcome in individual hard and soft tissues was relatively high. Using the TIOPS planning system with the presently included soft tissue algorithms, the current study shows relatively high mean predictability of the immediately postoperative hard and soft tissue outcome, independent of the extent and direction of required orthognathic correction. Because of the relatively high individual variability, caution is required when presenting the planned and predicted positional changes in the hard and soft tissue preoperatively in individual patients.

Accuracy of combined maxillary and mandibular repositioning and of soft tissue prediction in relation to maxillary antero-superior repositioning combined with mandibular set back A computerized cephalometric evaluation of the immediate postsurgical outcome using the TIOPS planning system.

AIM: The purpose of the present study was to evaluate the immediate postsurgical outcome of planned and predicted hard and soft tissue positional changes in relation to maxillary antero-superior repositioning combined with mandibular set back using the computerized, cephalometric, orthognathic surgical planning system (TIOPS). MATERIAL AND METHODS: Out of 100 prospectively and consecutively treated patients, 52 patients manifested dentofacial deformities requiring bimaxillary orthognathic surgery with maxillary antero-superior repositioning combined with mandibular set back and so were included. All patients were managed with rigid internal fixation (RIF) and without intermaxillary fixation (IMF). Preoperative cephalograms were analyzed and treatment plans and prediction tracings produced by computerized surgical interactive simulation. The planned horizontal and vertical hard tissue positional changes were transferred to model surgery on a three-dimensional articulator system (SAM) and finally to surgery. Five to six weeks after surgery, the actually obtained hard and soft tissue profile changes were cephalometricly assessed. RESULTS: The mean accuracy of the planned and predicted hard and soft tissue outcome was relatively high varying from 0.0mm to 0.5mm from one cephalometric reference point to another. At the cephalometric reference points where significant differences between planned/predicted, and actually obtained hard and soft tissue positional changes were demonstrated, these significant inaccuracies were, except for the predicted horizontal position of the lower lip, relatively small, varying from 0.2mm to 1.1mm. However, the variability of the predicted hard and soft tissue individual outcome was relatively high. CONCLUSION: The current study demonstrates from a mean point of view relatively high predictability of the immediate postsurgical hard and soft tissue outcome. However, as the variability of the predicted individual outcome seems to be relatively high, caution should be taken when presenting the planned and predicted hard and soft tissue positional changes to the individual patient, preoperatively.

Effect of early or delayed treatment upon healing of mandibular fractures: a systematic literature review.

The possible relation between treatment delay and healing complications in mandibular fracture treatment (excluding condylar fractures) was reviewed systematically. Twenty-two studies were identified. No randomized studies focused on the effect of immediate or delayed treatment. The main focus of most studies was surgical repositioning and internal skeletal fixation. The healing complications analyzed in this study were infection in the fracture line and malocclusion. Statistical analysis of the influence of treatment delay upon healing complications was possible in six studies. Four studies showed no significant difference between immediate and delayed treatment. One study showed a preference for healing for cases treated within 3 days, whereas another study indicated that treatment time between 3 and 5 days were optimal with the lowest rate of complications. Finally, a few studies identified confounding factors such as alcohol, drug abuse and/or non-compliance, factors which have been shown strongly to influence the likelihood of complications. A significant problem in this analysis was that rather few patients were actually treated on an acute basis (i.e. within 12 or 24 hours after injury), a fact which together with the lack of control of confounding factors made this analysis problematic. In conclusion, there is presently no strong evidence for either acute or delayed treatment of mandibular fractures in order to minimize healing complications; new studies including a substantial number of cases treated on an acute basis are very much needed.

Characterization of human bone cells derived from the maxillary alveolar ridge.

In this study, we have characterized bone cell cultures derived from the human maxillary alveolar ridge, which could be a potential cell source for tissue engineering of the severely resorbed maxilla. From 10 individuals, an osseous core was obtained. Without the use of collagenase, 10 explant cultures were established and the morphology of the cells (human maxilla-derived cells (hMDCs)) was studied with light microscopy (LM). Explant cultures were analyzed by flow cytometry with respect to size, granularity and surface marker expression. Fluorochrom-conjugated monoclonal antibodies (CD13, CD31, CD44, CD90 or CD73) were used. hMDCs were cultured in standard medium (SCM) or osteoinductive medium (OIM) for 21 days and analyzed for the presence of alkaline phosphatase (ALP) and calcium deposits (Von Kossa). Furthermore, osteogenic gene expression (osteocalcin [OC], ALP, collagen type 1) were analyzed by reverse transcription polymerase chain reaction (RT-PCR). LM demonstrated that hMDCs had a polygonal morphology containing a central nucleus with two to three nucleoli. Size/granularity analysis revealed differences between individuals. Immunophenotypically, these cells were positive for CD13, CD44, CD90 and CD73 while negative for CD31. Cells cultured in SCM for 21 days showed moderate ALP staining and many calcium deposits. Culturing cells in OIM for 21 days significantly increased both ALP staining and the number of calcium deposits. RT-PCR demonstrated expression of osteogenic marker genes and the ability to upregulate osteocalcin and ALP in response to osteogenic inducers. To our knowledge, it is the first time that surface marker expression has been studied on bone cells originating from this site. Cells were positive for markers characteristic for immature mesenchymal stem cells and had osteogenic differentiation capability. This study indicates that cells derived from maxillary biopsies could be a potential cell source for bone tissue engineering.

Management of oral disease prior to radiation therapy.

Radiation therapy for malignant tumors of the head and neck is associated with significant side effects involving the oral cavity. For example, radiation therapy leads to reduced vascularity and oxygen tension of the oral hard and soft tissues and also to salivary gland dysfunction. These changes increase the risk of dental decay and oral infections and lead to reduced healing capacity following oral surgery procedures. A severe complication of radiation therapy is osteoradionecrosis of the jaw bone. The purpose of this paper is to review preradiation oral examination and treatment. Patient management regarding oral disease prior to radiation therapy has to accomplish a number of goals: (1) to identify existing oral disease and potential risk of oral disease, (2) to remove infectious dental/oral foci before the start of radiation therapy, (3) to prepare the patient for the expected side effects with information about them, (4) to establish an adequate standard of oral hygiene to meet the increased challenge, (5) to provide a plan for maintaining oral hygiene and fluoride treatment, for oral rehabilitation, and for follow-up and (6) to inform the patient about the availability of any financial support for dental treatment, and finally (7) to establish the necessary multidiciplinary collaboration within the health care system so that oral symptoms and sequelae before, during and after the radiation therapy can be reduced or alleviated. The methods used to accomplish these goals may vary between cancer centers. Each center should have a multidisciplinary team to handle such problems. After the end of radiation therapy most of the dental treatments in our patients are done by private dentists, except for some oral surgery procedures, which are performed in hospital. In our experience, the major challenge in this process is related to (1) informing of the patient, (2) timing the coordination between all the health care workers involved, (3) establishing an adequate schedule for dental treatment and follow-up, and (4) securing patient compliance to prevent or reduce the oral side effects.