Osteogenesis distraction and platelet-rich plasma: combined use in restoration of severe atrophic mandible. Long-term results.

OBJECTIVES: The purpose of this paper is to report long-term results on the use of autologous bone graft and platelet-rich plasma in alveolar distraction osteogenesis (DO) for restoration of severe atrophic mandible. We tested the efficacy as to reabsorption of bone volume, peri-implant reabsorption, implant survival and success rate. MATERIALS AND METHODS: Twelve patients were treated. The surgical procedure consisted in mixing autologous bone, harvested from the iliac crest, with autologous platelet concentrate (APC) and in filling the distraction gap with this graft. After a latency of 15 days, a distraction rate of 0.5 mm/day was followed. After a 60-day period of consolidation, the distraction device was removed and implants were placed simultaneously. The abutment connection was accomplished after 6 months. In addition, every patient was evaluated clinically and radiographically annually for 5 years. RESULTS: Planned alveolar height was reached in 11 out of 12 patients. The total number of implants positioned was 47. At the time of implant positioning, the mean decrease of total bone volume was 2.3%. The mean peri-implant resorption was 0.40 mm at the time of abutment connection, 0.61 mm 1 year after implant loading and 1.51 mm after 5 years. After 5 years of follow-up, the mean rate of vertical bone loss was 18.7%. Instead, the implant survival and success rates were 97.9% and 91.5%, respectively. CONCLUSIONS: Long-term results allow us to confirm the combination of autologous bone-platelet gel with alveolar DO as an effective and predictable procedure in restoration of severe atrophic mandible.

Bone biological plate for stabilization of maxillary inferior repositioning.

AIM: Inferior repositioning of the maxilla to correct vertical maxillary deficiency has been one of the more unstable orthognathic procedures performed. Different surgical techniques have been proposed to stabilize downward movement of the maxilla. The aim of this study was to evaluate the skeletal stability of maxillary anterior downgrafting using bone biological plates in association to bone plates and bone graft for skeletal stabilization. METHODS: The records of 6 patients were evaluated cephalometrically, analyzing the presurgical, immediate postsurgical and long-term follow-up radiographs. All patients had one-piece Le Fort I osteotomy with anterior downgraft of at least 2 mm at point A. Any horizontal movement of the maxilla concomitant with the downgraft was no more than 5 mm. Rigid fixation with titanium miniplates and screws and with bone biological plate was used to stabilize the maxilla. In the sample of 6 patients, 3 underwent one-jaw (maxilla only) surgery and 3 two-jaw surgery. RESULTS: The mean surgical inferior downgrafting at point A was 5+/-1.4 mm (P<0.001) with a relapse of 0.16+/-1. 63 mm (3.2% of surgical movement). The mean surgical inferior downgrafting at the anterior nasal spine (ANS) was 5.66+/-1.36 mm (P<0.001) with a relapse of 0.41+/-1.56 mm (7.32% of surgical movement). Relapse in the vertical dimension failed to reach any statistical significance for all maxillary landmarks. CONCLUSIONS: Anterior downgrafting of the maxilla with this fixation method seems to be a stable and predictable procedure. The use of bone biological plates seems to substantially improve skeletal stability even if further investigations with a more consistent sample of patients is required.

Concordance of c-kit mutational status in matched primary and metastatic cutaneous canine mast cell tumors at baseline.

BACKGROUND: Mutation analysis of proto-oncogene c-kit (c-kit) is advisable before starting treatment with tyrosine kinase inhibitors in dogs with mast cell tumor (MCT), including those with metastatic disease. Testing is usually performed on primary tumors, assuming that c-kit mutation status does not change in metastasis. HYPOTHESIS/OBJECTIVES: To give an insight into the mutational processes and to make a recommendation on the use of c-kit mutational analysis in the clinical setting. ANIMALS: Twenty-one client-owned dogs with metastatic MCT. METHODS: Dogs undergoing resection or biopsy for both primary and matched metastatic MCT were prospectively enrolled. Total RNA or DNA was extracted from primary MCT and corresponding metastases. Exons 8, 9, and 11 were amplified by PCR and sequenced. Genetic features between primary MCT and metastases were compared. Their correlation with clinicopathologic features was investigated. RESULTS: Concordance (mutated or wild-type) of mutational status, evaluable in 21 primary and matched metastatic (20 nodal and 1 splenic) MCTs, was 100%. Three new c-kit mutations were identified. No significant correlation was detected between c-kit mutation and clinicopathologic features. CONCLUSIONS AND CLINICAL IMPORTANCE: Proto-oncogene c-kit mutational status is conserved between any primary and its matched secondary tumor, suggesting that both can be used for c-kit mutational testing. Targeted therapies might be also used to treat metastatic disease.