Reconstruction of Mandibular Continuity Defects Using Recombinant Human Bone Morphogenetic Protein 2: A Note of Caution in an Atmosphere of Exuberance

In situ shell technique for edentulous ridge augmentation

BACKGROUND

The novel two-stage technique presented in this study is based on guided bone regeneration for three-dimensional bone augmentation.

METHODS AND RESULTS

The proposed technique was performed to augment an atrophic alveolar ridge in the maxilla and mandible. This method is based on using an autogenous bone plate, a mixture of allogeneic bone graft and injectable -platelet-rich fibrin, and a bioresorbable barrier membrane. Based on the cases presented in this study, sufficient osseous regeneration was achieved to place dental implants in an ideal position.

CONCLUSION

Within the limitations of the present study, it seems that in situ shell technique could be a beneficial method to augment the extremely atrophied ridges with less morbidity and shorter operative time.

KEY POINTS

Why is this case new information? The cases presented a new technique using in situ autogenous plates for ridge augmentation. What are the keys to the successful management of this case? The keys to the successful management of these cases are proper flap management and less traumatic bony plate preparation. What are the primary limitations to success in this case? The primary limitation to success in this technique would be a need for high surgical skills to conduct the procedure accurately.

Clinical Outcome and 8-Year Follow-Up of Alveolar Bone Tissue Engineering for Severely Atrophic Alveolar Bone Using Autologous Bone Marrow Stromal Cells with Platelet-Rich Plasma and β-Tricalcium Phosphate Granules

Background: Although bone tissue engineering for dentistry has been studied for many years, the clinical outcome for severe cases has not been established. Furthermore, there are limited numbers of studies that include long-term follow-up. In this study, the safety and efficacy of bone tissue engineering for patients with a severely atrophic alveolar bone were examined using autogenous bone marrow stromal cells (BMSCs), and the long-term stability was also evaluated. Methods: BMSCs from iliac bone marrow aspirate were cultured and expanded. Then, induced osteogenic cells were transplanted with autogenous platelet-rich plasma (PRP) and β-tricalcium phosphate granules (β-TCP) for maxillary sinus floor and alveolar ridge augmentation. Eight patients (two males and six females) with an average age of 54.2 years underwent cell transplantation. Safety was assessed by monitoring adverse events. Radiographic evaluation and bone biopsies were performed to evaluate the regenerated bone. Results: The major population of transplanted BMSCs belonged to the fraction of CD34⁻, CD45^dim, and CD73⁺ cells, which was only 0.065% of the total bone marrow cells. Significant deviations were observed in cell growth and alkaline phosphatase activities among individuals. However, bone regeneration was observed in all patients and the average bone area in the biopsy samples was 41.9% 6 months following transplantation, although there were also significant deviations among each case. No adverse events related to the transplants were observed. In the regenerated bone, 27 out of 29 dental implants were integrated. Dental implants and regenerated bone were stable for an average follow-up period of 7 years and 10 months. Conclusions: Although individual variations were observed, the results showed that bone tissue engineering using BMSCs with PRP and β-TCP was feasible for patients with severe atrophic maxilla throughout a long-term follow-up period and was considered safe. However, further studies with a larger number of cases and controls to confirm the efficacy of BMSCs and the development of a protocol to establish a reproducible quality of stem cell-based graft material will be required.

Iliac crest bone grafting for mandibular reconstruction: 10-year experience outcomes

Purpose

To evaluate 10-year patient data related to mandibular reconstruction with NVBG at a tertiary academic center.

Patients and Methods

Sixty patients with mandibular mandibular reconstruction were included. Patients were divided to continuity defect and non-continuity defect. Pathology lesion, immediate reconstruction, smoking habit, medical comorbidities, site and size of the defect, surgical approach, intraoperative perforation, cadaveric bone use, and maxilla-mandibular fixation use were analyzed as factors of influence on success. Success was defined as maintenance of more than 50% of graft for non-continuity defects (NCD) and bone continuity and stability for continuity defect (CD), and absence of infection on last follow up upon clinical and radiographic examination. Complications were classified as minor or major.

Results

The reconstruction was successful in 28 (87%) of CD patients and 23 (82.1%) of NCD patients. Analyses showed that the size of defect was significantly associated with failure. All 4 failed cases of CD had defects more than 9 cm. Four patients had major complications and 43 minor complication.

Conclusions

Nonvascularized iliac crest bone grafts are highly successful in mandibular continuity reconstruction for non-Cancer patients and should be considered as first choice for defects less than 9 cm. They are less predictable for defects larger than 9 cm but can be considered in these cases with osteoconductive cribs. Symphysis involvement may or may not be associated with lower success rate if our protocol is followed.

A historical perspective with current opinion on the management of atrophic mandibular fractures

The management of atrophic mandibular fractures has been a challenge for maxillofacial surgeons for decades. During the past 70 years, various techniques for treating edentulous mandibular fractures have been advocated. These techniques have been praised, criticized, abandoned, improved, and used in combination with other methods. Although some of the principles of management outlined before the end of World War II are still valid in today's technological era, other concepts did not survive the test of time. The aim of this paper is to examine the evolution of treatment modalities for the management of atrophic mandibular fractures that have been employed over the years. Debates and discussions generated by this topic are included. Current techniques and treatment philosophies with thoughts for future therapies are provided.

Atrophic Mandible Fractures: Are Bone Grafts Necessary? An Update

PURPOSE

The management of atrophic mandibular fractures poses a challenge because of anatomic variations and medical comorbidities associated with elderly patients. The purpose of this article is to review and update the literature regarding the management of atrophic mandible fractures using load-bearing reconstruction plates placed without bone grafts.

MATERIALS AND METHODS

We performed a review of the English-language literature looking for atrophic mandibular fractures with or without continuity defects and reconstruction without bone grafts. Included are 2 new patients from our institution who presented with fractures of their atrophic mandibles and had continuity defects and infections. Both patients underwent reconstruction with a combination of a reconstruction plate, recombinant human bone morphogenetic protein 2, and tricalcium phosphate. This study was approved as an "exempt study" by the Institutional Review Board at the University of Kentucky. This investigation observed the Declaration of Helsinki on medical protocol and ethics.

RESULTS

Currently, the standard of care to manage atrophic mandibular fractures with or without a continuity defect is a combination of a reconstruction plate plus autogenous bone graft. However, there is a need for an alternative option for patients with substantial comorbidities. Bone morphogenetic proteins, with or without additional substances, appear to be a choice. In our experience, successful healing occurred in patients with a combination of a reconstruction plate, recombinant human bone morphogenetic protein 2, and tricalcium phosphate.

CONCLUSIONS

Whereas primary reconstruction of atrophic mandibular fractures with reconstruction plates supplemented with autogenous bone graft is the standard of care, in selected cases in which multiple comorbidities may influence local and/or systemic outcomes, bone morphogenetic proteins and tricalcium phosphate can be used as a predictable alternative to autogenous grafts.

Off-Label Use of Bone Morphogenetic Protein 2 in the Reconstructions of Mandibular Continuity Defects

This paper describes 3 patients of off-label use of bone morphogenetic protein 2 (rhBMP-2) in the reconstruction of mandibular continuity defects. In the first patient, rhBMP-2 was associated with iliac crest bone graft for late mandibular reconstruction after resection of osteosarcoma. In the 2 other patients, rhBMP-2 was used alone. In 1 patient the mandibular continuity defect was due to resection for treatment of osteomyelitis and in the other patient a continuity defect was created by unsuccessful osteogenic distraction for correction of mandibular hypoplasia. Despite the good results in those patients, the off-label use of rhBMP-2 is associated with increased rate of complications, so more studies are needed to assess the predictability of the use of rhBMP-2 in mandibular continuity defects. Therefore, at the moment the off-label use of rhBMP-2 should be restricted to complicated bone defects in which the conventional alternatives of reconstruction were unsuccessful.

Regeneration of a Tooth in a Tissue-Engineered Mandible After Resection of a Central Giant Cell Tumor. Demonstrating Evidence of Functional Matrix Theory and Ectodermal Origin of Teeth in a Human Model-A Case Report

Central giant cell tumors (CGCTs) are uncommon lesions occurring in the jaw. They are benign but locally destructive osteolytic lesions. They usually occur in pediatric patients 5 to 15 years of age. Multiple noninvasive modalities of treatment (intralesional steroids, interferon, calcitonin, and denosumab) have been described for those lesions, but for those that are refractory to treatment, enucleation and curettage or resection is a curative surgery. This case report describes a pediatric patient who was diagnosed with an aggressive CGCT of the left mandible encompassing the right angle to the condyle. The lesion became refractory to noninvasive treatments and immediate resection and reconstruction was performed using principles of tissue engineering. After 5 years of close observation, the patient showed normal morphology and growth of his mandible, but surprisingly developed a left mandibular third molar (tooth 17) in the site of the mandibular resection and reconstruction. This is the first case report in the literature to show the spontaneous development of teeth in a human reconstructed mandible, contributing evidence toward the functional matrix theory of mandibular growth and ectodermal origin of teeth.

Resection of an ameloblastoma in a pediatric patient and immediate reconstruction using a combination of tissue engineering and costochondral rib graft: A case report

BACKGROUND AND OVERVIEW

Ameloblastoma is an odontogenic tumor predominantly occurring in patients who are in their 20s and 30s. Approximately 10% to 15% of ameloblastomas occur in patients younger than 18 years. Although it is a benign tumor, an ameloblastoma can have a devastating effect on children both physically and emotionally. The aim of this case report is to demonstrate how tissue engineering and surgical techniques can minimize morbidity and recovery time after extirpation and immediate reconstruction of a mandibular ameloblastoma.

CASE DESCRIPTION

An 11-year-old girl was referred for surgical evaluation of a lesion found on a routine dental radiograph. Resection of a mandibular unicystic ameloblastoma resulted, including immediate reconstruction using a costochondral rib graft, allogeneic bone, bone marrow aspirate concentrate, and recombinant human morphogenetic protein-2. One year postoperatively, the patient had no evidence of recurrence as well as excellent mandibular bone height and width with good facial form. The patient has returned to her daily life without any disabilities or disfigurement.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

Dentists are typically the first health care providers to discover oral pathology in patients. The coordination of care by the dental care providers and the oral and maxillofacial specialist was key to the successful outcome for this patient. With biotechnology and surgical techniques, the dental surgeon can extirpate an ameloblastoma and reconstruct the mandible defect to the ideal shape and size with minimal morbidity and recovery time.

Retrospective evaluation of 211 patients with maxillofacial reconstruction using parietal bone graft for implants insertion

PURPOSE

For a century, autologous bone grafts have been used in maxillofacial reconstruction. The ideal bone harvest site and grafting procedure remains a point of contention in regards to obtaining optimal long-term results with sufficient bone quantity and density without serious complications. More recently, confronted with growing patient requests and biomaterials development, maxillofacial surgeons and dentists have been considering these issues as they relate to pre-implant surgery. This study sought to evaluate implant success rate and complications following pre-implant surgery with parietal bone grafting.

MATERIALS AND METHODS

A retrospective study was carried out on patients who underwent maxillofacial reconstruction of different sites (symphysis, mandibular corpus, maxillary sinus and premaxilla) for the purpose of implant insertion.

RESULTS

311 procedures in 211 patients were included. The implant osseointegration rate was around 95%. Clinical follow-up ranged from 10 months to 11 years. A secondary procedure was performed in 6.1% of cases and we noted no serious complications at the harvest site.

DISCUSSION

With good revascularization and osseointegration of the graft, the use of parietal bone leads to an implant success rate similar to that seen in the literature. Moreover, the use of this material results in few infections and low bone resorption provided there is strict immobilization of the graft and no tension on the soft tissue sutures.

CONCLUSION

Parietal bone grafts technique possess the required qualities for the success of implant surgery, offering results at least as interesting as others using autogenous bone and with no serious complications on donor site.

Nanodiamond modified copolymer scaffolds affects tumour progression of early neoplastic oral keratinocytes

This study aimed to evaluate the tumorigenic potential of functionalising poly(LLA-co-CL) scaffolds. The copolymer scaffolds were functionalised with nanodiamonds (nDP) or with nDP and physisorbed BMP-2 (nDP-PHY) to enhance osteoinductivity. Culturing early neoplastic dysplastic keratinocytes (DOK(Luc)) on nDP modified scaffolds reduced significantly their subsequent sphere formation ability and decreased significantly the cells' proliferation in the supra-basal layers of in vitro 3D oral neoplastic mucosa (3D-OT) when compared to DOK(Luc) previously cultured on nDP-PHY scaffolds. Using an in vivo non-invasive environmentally-induced oral carcinogenesis model, nDP scaffolds were observed to reduce bioluminescence intensity of tumours formed by DOK(Luc) + carcinoma associated fibroblasts (CAF). nDP modification was also found to promote differentiation of DOK(Luc) both in vitro in 3D-OT and in vivo in xenografts formed by DOK(Luc) alone. The nDP-PHY scaffold had the highest number of invasive tumours formed by DOK(Luc) + CAF outside the scaffold area compared to the nDP and control scaffolds. In conclusion, in vitro and in vivo results presented here demonstrate that nDP modified copolymer scaffolds are able to decrease the tumorigenic potential of DOK(Luc), while confirming concerns for the therapeutic use of BMP-2 for reconstruction of bone defects in oral cancer patients due to its tumour promoting capabilities.

Ultrasonic Welded Resorbable Mesh (SonicWeld Rx System) in Reconstruction of Segmental Mandibular Defects: Technical Note and Report of 2 Cases

The present report describes 2 patients who underwent mandibular reconstruction after segmental mandibulectomy for benign pathology. The potential of an ultrasonic-aided biodegradable system for containment of a nonvascularized bone graft is discussed.

Is immediate reconstruction of the mandible with nonvascularized bone graft following resection of benign pathology a viable treatment option?

PURPOSE

The purpose of this study was to address the following clinical question: Is immediate reconstruction of the mandible with a nonvascularized bone graft after resection of benign pathology a viable treatment option? Another purpose was to determine whether any variables affect the success of this treatment approach.

MATERIALS AND METHODS

The authors implemented a retrospective cohort study from a sample of patients diagnosed with a benign tumor of the mandible who were treated with segmental resection and primary reconstruction with an autogenous nonvascularized bone graft. The predictor variables were age, gender, lesion size, and diagnosis, and the outcome variable was graft success determined by re-establishment of mandibular continuity with sufficient bone for implant placement. The χ(2) test was used for statistical analysis of the categorical data and P values less than .05 were considered statistically significant.

RESULTS

Twenty patients with benign mandibular tumors were treated with transoral resection and immediate reconstruction with nonvascularized bone grafts. The mean age was 28.3 years (range, 9 to 63 yr) and 55% (11 of 20) were men. The most common lesion type was ameloblastoma (13 of 20) and all patients underwent reconstruction with autogenous anterior iliac crest bone grafting. Ninety percent of patients (18 of 20) had successful reconstruction. Ten patients underwent successful implant placement and restoration.

CONCLUSIONS

Using careful patient selection, treatment of benign pathology with transoral resection and immediate reconstruction with a nonvascularized bone graft from the anterior iliac crest can be successful. In addition, the total treatment time from implant restoration to return to preoperative function is minimized. Therefore, this method of treatment is a viable treatment option and an alternative to delayed reconstruction or reconstruction with vascularized bone flaps.