Giant Mandibular Ameloblastoma with Rare Hypercalcemia: A Case Report and Literature Review.

Ameloblastoma is the most common benign odontogenic tumor with local invasion and high recurrence, which generally occurs in the jaw bones. Hypercalcemia is a common paraneoplastic syndrome that is commonly observed in patients with malignancies but rarely encountered in patients with benign tumors. Thus far, not many cases of ameloblastoma with hypercalcemia have been reported, and the pathogenic mechanism has not been studied in depth. This paper presents a case report of a 26-year-old male diagnosed with giant ameloblastoma of the mandible, accompanied by rare hypercalcemia. Additionally, a review of the relevant literature is conducted. This patient initially underwent marsupialization, yet this treatment was not effective, which indicated that the selection of the appropriate operation is of prime importance for improving the prognosis of patients with ameloblastoma. The tumor not only failed to shrink but gradually increased in size, accompanied by multiple complications including hypercalcemia, renal dysfunction, anemia, and cachexia. Due to the contradiction between the necessity of tumor resection and the patient's poor systemic condition, we implemented a multi-disciplinary team (MDT) meeting to better evaluate this patient's condition and design an individualized treatment strategy. The patient subsequently received a variety of interventions to improve the general conditions until he could tolerate surgery, and finally underwent the successful resection of giant ameloblastoma and reconstruction with vascularized fibular flap. No tumor recurrence or distance metastasis was observed during 5 years of follow-up. Additionally, the absence of hypercalcemia recurrence was also noted.

Digitally prefabricated versus conventionally fabricated implant-supported full-arch provisional prosthesis: a retrospective cohort study.

BACKGROUND: To evaluate and compare the clinical outcomes of digitally prefabricated and conventionally fabricated implant-supported full-arch provisional prostheses. METHODS: In this retrospective study, a total of 39 patients (22 males and 17 females) who underwent implant-supported full-arch rehabilitation using the All-on-4 concept with an immediate loading protocol were included: 20 patients treated with digitally prefabricated provisional prostheses were assigned into Group A, and 19 patients treated with conventionally fabricated provisional prostheses were assigned into Group B. Implant/provisional prosthesis survival rates and complications were reviewed. Marginal bone loss (MBL) was investigated by CBCT. Surgical time, restorative time, and total operative time were analyzed. Postoperative pain and swelling were evaluated with the visual analog scale (VAS). The oral health impact profile (OHIP) questionnaire was administered before and after surgery. RESULTS: The implant/provisional prosthesis survival rate was 100%, and complications appeared with low frequency in both groups, while the mean MBL was 0.30 ± 0.29 mm in Group A and 0.31 ± 0.41 mm in Group B after 3~ 6 months (P > 0.05). The average restorative time in Group A (116.16 ± 16.61 min) was significantly shorter than that in Group B (242.11 ± 30.14 min) (P < 0.05). Patients in Group A showed lower pain/swelling VAS scores after surgery than Group B (P < 0.05). Low OHIP scores with high satisfaction with the overall effects were shown in both groups. CONCLUSION: Prefabricated prostheses reduced the prosthetic time and postoperative discomfort in patients whose immediate rehabilitation was based on the All-on-4 concept. This prefabrication technology may be a predictable alternative to improve the short-term clinical outcome of implant-supported full-arch provisional rehabilitation.

A Rare Kimura's Disease in the Oral Cavity with Severe Sleep Apnea: Case Report and Literature Review.

Kimura's disease (KD) is a rare chronic inflammatory disorder that commonly occurs in Asian males. It mainly presents as painless subcutaneous masses or lymphadenopathy in the head and neck region. The incidence of KD in the oral cavity is quite rare. We reported a rare case of a 53-year-old male who had KD in his soft palate, hard palate and bilateral tonsils associated with severe sleep apnea. This patient underwent radiotherapy and exhibited a good response to the treatment. Throughout the 12-month follow-up period, the patient's condition remained satisfactory. Of the other 14 reviewed cases of KD in the oral cavity, the lesions can occur in the buccal mucosa, hard and soft palate, and mouth floor with specific clinical features. We further summarized their manifestations and treatments in order to guide the future identification and management of KD with lesions in the oral cavity.

A Retrospective Study of 158 Cases on the Risk Factors for Recurrence in Ameloblastoma.

Background: Ameloblastoma is an odontogenic tumor occurring in jaws, with local aggressiveness and postoperative recurrence. This study was aim to investigate the clinical and radiographic risk factors for recurrence in ameloblastoma. Methods: Patients diagnosed with ameloblastoma between March 2009 and March 2019 were retrospectively analyzed. Clinical and Radiological data and follow-up records were collected. Survival analyses were performed by Kaplan-Meier and log-rank tests, as well as Cox proportional hazards model. Results: One hundred and fifty-eight patients (104 males and 54 females were enrolled. The overall recurrence rate for ameloblastoma was 13.29%, and 10.76% recurred within 5 years. Most of the tumors were located in mandible (86.71%), while the rest 21 cases were in maxilla (13.29%). More than half cases (55.06%) showed multilocular radiolucency, 61 cases (38.61%) showed unilocular radiolucency. Significant differences were found with amelobastoma recurrence rate related to treatment modality, impacted tooth and root resorption (P =0.002, 0.022 and 0.007 respectively). Conclusions: Treatment modality, impacted tooth and root resorption all showed statistically significant associations with the recurrence rate in ameloblastoma. However, due to the limitation of this study, further studies are needed to reveal the true mechanism of ameloblastoma recurrence.

Technical procedures for template-guided surgery for mandibular reconstruction based on digital design and manufacturing.

BACKGROUND: The occurrence of mandibular defects caused by tumors has been continuously increasing in China in recent years. Conversely, results of the repair of mandibular defects affect the recovery of oral function and patient appearance, and the requirements for accuracy and high surgical quality must be more stringent. Digital techniques--including model reconstruction based on medical images, computer-aided design, and additive manufacturing--have been widely used in modern medicine to improve the accuracy and quality of diagnosis and surgery. However, some special software platforms and services from international companies are not always available for most of researchers and surgeons because they are expensive and time-consuming. METHODS: Here, a new technical solution for guided surgery for the repair of mandibular defects is proposed, based on general popular tools in medical image processing, 3D (3 dimension) model reconstruction, digital design, and fabrication via 3D printing. First, CT (computerized tomography) images are processed to reconstruct the 3D model of the mandible and fibular bone. The defect area is then replaced by healthy contralateral bone to create the repair model. With the repair model as reference, the graft shape and cutline are designed on fibular bone, as is the guide for cutting and shaping. The physical model, fabricated via 3D printing, including surgical guide, the original model, and the repair model, can be used to preform a titanium locking plate, as well as to design and verify the surgical plan and guide. In clinics, surgeons can operate with the help of the surgical guide and preformed plate to realize the predesigned surgical plan. RESULTS: With sufficient communication between engineers and surgeons, an optimal surgical plan can be designed via some common software platforms but needs to be translated to the clinic. Based on customized models and tools, including three surgical guides, preformed titanium plate for fixation, and physical models of the mandible, grafts for defect repair can be cut from fibular bone, shaped with high accuracy during surgery, and fixed with a well-fitting preformed locking plate, so that the predesigned plan can be performed in the clinic and the oral function and appearance of the patient are recovered. This method requires 20% less operating time compared with conventional surgery, and the advantages in cost and convenience are significant compared with those of existing commercial services in China. CONCLUSIONS: This comparison between two groups of cases illustrates that, with the proposed method, the accuracy of mandibular defect repair surgery is increased significantly and is less time-consuming, and patients are satisfied with both the recovery of oral function and their appearance. Until now, more than 15 cases have been treated with the proposed methods, so their feasibility and validity have been verified.

Efficacy of bone grafts in jaw cystic lesions: A systematic review.

BACKGROUND: Bone grafts have been applied for many years in orthopedic surgery to assist with bone repair for defects or bone discontinuity caused by trauma and tumors as well as periodontal defects. Jaw cysts are another common benign disease of the maxillofacial region which may lead to pathological bone fracture, loss of teeth, and infection. However, whether bone grafts are beneficial for bone regeneration in jaw cystic lesions and when bone grafts should be used remains unclear. AIM: To study the efficacy of bone grafts compared to spontaneous healing in the treatment of jaw cystic lesions. METHODS: A literature search was performed in Medline, Cochrane Library and Embase to identify related articles published in English in the last ten years. The following key words and MeSH terms were used: "jaw cyst", "cystic lesion", "odontogenic cyst", "periapical cyst", "dentigerous cyst", "follicular cyst", "keratocyst", "treatment", "surgery", "bone graft", "enucleation", "cystectomy", and "bone regeneration". Case reports, clinical trials, clinical studies, observational studies and randomized controlled trials were included. Study quality was evaluated. RESULTS: Ten studies (n = 10) met the inclusion criteria. Five studies reported spontaneous bone healing after enucleation, three studies investigated the efficacy of various bone grafts, and two randomized comparative studies focused on the comparison between spontaneous healing and bone grafting. Over 90% of bone regeneration occurred within 6 mo after bone grafting. The bone regeneration rate after cystectomy showed great variation, ranging from 50% to 100% after 6 mo, but reaching over 90% after 12 mo. CONCLUSION: While the long-term superiority of bone grafting compared with spontaneous healing after cystectomy is unclear, bone grafts accelerate the process of healing and significantly increase bone quality.

Modification of polyetheretherketone (PEEK) physical features to improve osteointegration.

Polyetheretherketone (PEEK) has been widely applied in orthopedics because of its excellent mechanical properties, radiolucency, and biocompatibility. However, the bioinertness and poor osteointegration of PEEK have greatly limited its further application. Growing evidence proves that physical factors of implants, including their architecture, surface morphology, stiffness, and mechanical stimulation, matter as much as the composition of their surface chemistry. This review focuses on the multiple strategies for the physical modification of PEEK implants through adjusting their architecture, surface morphology, and stiffness. Many research findings show that transforming the architecture and incorporating reinforcing fillers into PEEK can affect both its mechanical strength and cellular responses. Modified PEEK surfaces at the macro scale and micro/nano scale have positive effects on cell-substrate interactions. More investigations are necessary to reach consensus on the optimal design of PEEK implants and to explore the efficiency of various functional implant surfaces. Soft-tissue integration has been ignored, though evidence shows that physical modifications also improve the adhesion of soft tissue. In the future, ideal PEEK implants should have a desirable topological structure with better surface hydrophilicity and optimum surface chemistry.

Deep learning based diagnosis for cysts and tumors of jaw with massive healthy samples.

We aimed to develop an explainable and reliable method to diagnose cysts and tumors of the jaw with massive panoramic radiographs of healthy peoples based on deep learning, since collecting and labeling massive lesion samples are time-consuming, and existing deep learning-based methods lack explainability. Based on the collected 872 lesion samples and 10,000 healthy samples, a two-branch network was proposed for classifying the cysts and tumors of the jaw. The two-branch network is firstly pretrained on massive panoramic radiographs of healthy peoples, then is trained for classifying the sample categories and segmenting the lesion area. Totally, 200 healthy samples and 87 lesion samples were included in the testing stage. The average accuracy, precision, sensitivity, specificity, and F1 score of classification are 88.72%, 65.81%, 66.56%, 92.66%, and 66.14%, respectively. The average accuracy, precision, sensitivity, specificity, and F1 score of classification will reach 90.66%, 85.23%, 84.27%, 93.50%, and 84.74%, if only classifying the lesion samples and healthy samples. The proposed method showed encouraging performance in the diagnosis of cysts and tumors of the jaw. The classified categories and segmented lesion areas serve as the diagnostic basis for further diagnosis, which provides a reliable tool for diagnosing jaw tumors and cysts.

Use of anterior ramus bone graft for mandibular reconstruction in elderly patients.

In this study, we investigated the feasibility of using a geometrically designed anterior ramus graft to reconstruct lateral mandibular defects. This was achieved by assessing the anatomical dimensions of the mandibular ramus on computed-tomographies. The design sequence and application of the graft was also demonstrated using one of our cases. The following dimensions were measured; a and b - horizontal length from mid-ramus to the posterior and anterior ramus border respectively, c - longest length of the graft, Mp - width at the centre of the ramus, h - vertical length of the angle at its cross-section, w - horizontal length of the angle at its cross-section, x - cross-sectional area along the mandible angle. A total of 80 mandibular rami were examined. The mean length of a, b, c were 17.3 ± 1.8 mm, 15.9 ± 1.2 mm, 54.6 ± 3.8 mm, respectively. The mean width of Mp was 9.8 ± 1.1 mm. The mean cross section area of Eo-Md (x) was 326.7 ± 67.8 mm2. The average length of h and w were 26.5 ± 3.2 and 15.6 ± 2.1 mm, respectively. The use of virtual surgical planning (VSP) to geometrically design the graft was also described. Together with VSP, the anterior ramus bone graft will allow for reconstruction of the mandible with greater surgical efficiency, reduced complexity and without the need for extra-oral bone harvest. This may be an useful alternative in situations where simpler reconstructive procedures are preferred.

Clinical Outcomes After Primary Implantation into Modified One-and-a-Half-Barrel Fibula Free Flap Reconstructed Mandible.

PURPOSE: The aim of this study was to introduce and evaluate a modified one-and-a-half-barrel fibular technique guided by occlusion for functionally reconstructing mandibular defects. MATERIALS AND METHODS: Fifteen patients underwent mandibular reconstruction with the modified one-and-a-half-barrel technique and simultaneous insertion of dental implants. A vascularized fibular segment was used to reconstruct the alveolar ridge of the neomandible with dental implants loaded simultaneously. The inferior border was reconstructed with a nonvascularized segment. Panoramic radiographs were taken 1 week, 6 months, and 12 months after the surgery to measure the vertical height of the fibular segment, calculate the bone resorption rate at different time points, and observe the implant marginal bone loss and crown-to-implant ratio. The OHIP-14 questionnaire was employed to evaluate the perceived outcomes of oral rehabilitation. RESULTS: The vertical height of the vascularized and nonvascularized fibular segments 1 week, 6 months, and 12 months after the surgery was 14.51 ± 1.93, 14.19 ± 1.88, and 13.81 ± 1.78 mm; and 8.65 ± 0.98, 7.72 ± 0.94, and 7.25 ± 0.93 mm, respectively. The bone resorption rate of vascularized and nonvascularized fibular segments was 2.20% ± 1.04% and 10.69% ± 5.73%, respectively, in the first 6 months, and 2.67% ± 1.44% and 6.16% ± 2.75%, respectively, in the latter 6 months, showing a significantly higher resorption rate in the nonvascularized segment (P < .05). The implant marginal bone loss after functional loading was significantly greater than that before dental rehabilitation (P = .001). The OHIP-14 total scores were 20.07 ± 10.24, 19.00 ± 7.82, and 3.93 ± 1.87 before surgery, at 6 months, and at 12 months after surgery, respectively (P = .000). CONCLUSION: The proposed technique not only guarantees the esthetic appearance of patients but also achieves a suitable vertical height to facilitate the placement of the implant at the same time.

Trismus originating from rare fungal myositis in pterygoid muscles: A case report.

BACKGROUND: Trismus is a common problem with various causes. Any abnormal conditions of relevant anatomic structures that disturb the free movement of the jaw might provoke trismus. Trismus has a detrimental effect on the quality of life. The outcome of this abnormality is critically dependent on timely diagnosis and treatment, and it is difficult to identify the true origin in some cases. We present a rare case of trismus due to fungal myositis in the pterygoid muscle, excluding any other possible pathogenesis. CASE SUMMARY: The patient presented with a 2-mo history of restricted mouth opening. Computed tomography showed obvious enlargement of the left pterygoid muscles. Furthermore, the patient had trismus without obvious predisposing causes. The primary diagnosis was pterygoid myosarcoma. Consequently, lesionectomy of the left pterygoid muscle was performed. Intraoperative frozen biopsy implied the possibility of an uncommon infection. Postoperative pathologic examination confirmed myositis and necrosis in the pterygoid muscle. Fungi were detected in both muscle tissue and surrounding necrotic tissue. The patient recovered well with antifungal therapy and mouth opening exercises. The rarity of fungal myositis may be responsible for the misdiagnosis. Although the origin of pathogenic fungi is still unknown, we believe that both hematogenous spread and local invasion could be the most likely sources. To the best of our knowledge, this is the first case in the literature that reported fungal myositis in pterygoid muscles as the only reason that results in trismus. CONCLUSION: Surgeons should remain vigilant to the possibility of trismus originating from fungal myositis.

Human bone marrow stroma stem cell distribution in calcium carbonate scaffolds using two different seeding methods.

OBJECTIVE: The aim of this study was to develop a method for the determination of the three-dimensional (3D) distribution of cells in mineralized scaffolds and to compare the effect of two different methods of cell seeding of human bone marrow stroma cells (hBMSCs) in long-term cultures. MATERIALS AND METHODS: hBMSCs were seeded into CaCO(3) scaffolds by droplet seeding using culture medium with and without the addition of fibrin. After 2, 7, 14, and 21 days of culture, the constructs were embedded into methylmethacrylate and serially sectioned using undecalcified thick section technology. Sections were serially scanned from the surface to the bottom of the scaffolds and DAPI-stained cells were automatically counted in each section using structured illumination fluorescence microscopy (FM) with serial optical sectioning and image analysis software. RESULTS: The data showed that the seeding efficiency was significantly higher in the scaffolds seeded with the addition of fibrin. Moreover, the number of cells increased to higher levels and remained higher for longer periods with the use of the fibrin matrix, whereas cells seeded in the medium suspension exhibited a sharp decrease after the first week of cultivation. There were distinct differences in the 3D cell distribution between the center and the periphery of the scaffolds. The use of a fibrin matrix was associated with a more uniform cell distribution 1 and 2 weeks after seeding in different levels (center vs. periphery: P>0.05), whereas cells in the medium solution group accumulated at the periphery of the scaffolds. CONCLUSIONS: In conclusion, automated serial optical sectioning using structured illumination FM can assess cell numbers and the 3D distribution of hBMSCs in mineralized scaffolds. This allows for a detailed analysis of the effect of different in vitro procedures used for cell seeding. The use of fibrin during seeding increases seeding efficiency and enhances both proliferation and cell survival in the central parts of the scaffolds.

[Clinical application and accuracy analysis of occlusion-guided functional mandibular reconstruction].

OBJECTIVE: To investigate the influence of the design and application of novel surgical template on the accuracy of reconstructed mandibula and implant position in occlusion-guided functional mandibular reconstruction, so as to provide guidance for clinical treatment. METHODS: Between January 2017 and May 2019, 11 patients with segmental mandible defects were treated, including 8 males and 3 females with an average age of 31.8 years (range, 19-45 years). There were 6 cases of ameloblastoma, 3 cases of keratocystic tumor, and 2 cases of ossifying fibroma. According to Urken classification of mandible defects, there were 1 case of CRB, 4 cases of RB, 2 cases of RBS, and 4 cases of SB. According to the occlusion relationship, a novel surgical template with the reconstruction titanium plate screws and implants drill-guided information was designed and manufactured. With the help of the novel surgical template, the "one and a half" fibula reconstruction mode was used for jaw functional reconstruction, and the implant supported denture was finally completed. The postoperative CT at 1 week were collected to analyze the morphology of the preoperative virtual design jaw and postoperative jaw. The coincidence of fibular reconstructed mandible (fibular upper barrel, fibular reconstructed ramus and condyle, and whole mandible) and implant in mandible were calculated. When the coincidence was less than 80%, it was considered that the deviation was obvious. Oral panoramic X-ray film and cone beam CT were examined at 6 months after operation to evaluate the osseointegration before implant repair. RESULTS: None of the 11 flaps had postoperative vascular crisis. One flap occurred necrosis at 1 month after reconstruction combined with 3 implants failed, and had been removed at 6 months after reconstructed surgery; the others had no flap necrosis. One week postoperatively, the coincidence of the fibular upper barrel was 87.55%±3.08%, the whole mandible was 82.68%±5.94%, and the implant in mandible was 88.00%, with significant differences ( t=8.131, P=0.000; t=2.118, P=0.046; Z=4.070, P=0.000) when compared to 80%, respectively. The fibular reconstructed ramus and condyle was 77.82%±3.54%, with no significant difference ( t=-2.042, P=0.068) when compared to 80%. Six months postoperatively, oral panoramic X-ray film and cone beam CT showed that all 22 implants achieved osseointegration and the palatal mucosa transplantation was performed, then finally completed the denture rehabilitation at 6-9 months after operation. All patients were satisfied with their postoperative appearance. CONCLUSION: The novel surgical template can guarantee the accuracy of functional mandible reconstruction guided by occlusal guidance, and ultimately achieve the beautiful contour of jaw and occlusal function reconstruction, and improve the patient's life quality.

Harnessing the Properties of Biomaterial to Enhance the Immunomodulation of Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) have great therapeutic potential for tissue engineering and regenerative medicine due to their multipotency and paracrine functions. However, shortly after in vivo implantation, MSCs tend to migrate to the lungs and undergo apoptosis, which impairs their clinical efficacy. In addition, the ex vivo two-dimensional expansion of MSCs results in changes in their immunophenotype and functional activities compared to those in vivo. The use of biomaterials to culture and deliver MSCs has the potential to overcome these limitations. MSC-biomaterial constructs retain MSCs in situ and prolong their survival, while the MSCs ameliorate the foreign body reaction and fibrosis caused by the biomaterial. Biomaterial scaffolds can both preserve the tissue architecture and provide a three-dimensional biomimetic milieu for embedded MSCs, which enhance their paracrine functions, including their immunomodulatory potential. The dimensionality, physical characteristics, topographical cues, biochemistry, and microstructure can enhance the immunomodulatory potential of MSCs. Here, we review the link between the properties of biomaterial and the immunomodulatory potential of MSCs. Impact Statement Regeneration of cells, tissues, and whole organs is challenging. Mesenchymal stem cells (MSCs) have therapeutic potential in tissue engineering and regenerative medicine due to their paracrine functions, including immunomodulatory activity. The dimensionality, physical characteristics, topographical cues, biochemistry, and microstructure of biomaterial can be harnessed to enhance the immunomodulatory potential of MSCs for tissue engineering, which will increase their clinical efficacy, particularly for immune-related diseases.

Bone and dental abnormalities as first signs of familial Gardner's syndrome in a Chinese family: a literature review and a case report.

Gardner's syndrome (GS) is an autosomal dominant disease characterized by the presence of familial adenomatous polyposis (FAP) as well as extraintestinal manifestations such as osteomas, dental anomalies, epidermoid cysts and ocular abnormalities. These intestinal polyps carry a 100% risk of malignant change, so early diagnosis is crucial. As craniofacial osteomas and dental anomalies of GS usually precede gastrointestinal symptoms, otolaryngologists, oral surgeons and dentists play an important role in the diagnosis of GS. GS is extensively reported in literature in the Caucasian race but not in the Mongoloid race. We report a case of a 22-year-old patient with a manifestation of three features of GS - multiple osteomas, soft tissue tumors and dental anomalies in the craniofacial region, with no intestinal polyps at the time of reporting. A family pedigree with our patient as the proband was constructed and revealed 3 consecutive generations in his lineage with GS.

Less invasive management of deep neck infection and descending necrotizing mediastinitis: A single-center retrospective study.

By a 7-year retrospective review, we reported our experience in management of descending necrotizing mediastinitis (DNM) and deep neck infection (DNI). A retrospective design was used to reveal the clinical characteristics of DNI and DNM. The clinical outcome was analyzed to validate less invasive management. We reviewed 82 patients between 2009 and 2016, 12 of which were diagnosed as DNM by clinical and computed tomography findings. A total of 35 patients had relevant systemic conditions, mainly diabetes mellitus (19 patients). Most cases were secondary to oropharyngeal or dental infections. All patients underwent transcervical drainage, and 10 DNM patients were treated with additional closed thoracic drainage simultaneously. Twenty patients accepted more than 1 operation. Seven patients died as a result of sepsis and/or multiple organ failure. The mortality rate in our study was similar to that in other studies. In our opinion, less invasive therapies are useful to most patients. Transcervical drainage alone is optimal management for all DNI cases and some DNM cases. Additional closed thoracic drainage is enough for type I and IIA DNM with pleural effusion or empyema.

Primary small cell carcinoma with neuroendocrine properties of the mandible: A case report and literature review.

Small-cell carcinomas at extrapulmonary primary sites are rare but they have been documented to arise at various locations. We report a case of small-cell carcinoma arising in the mandible, which has so far not been reported in the literature. A 37-year-old male patient underwent partial resection of the left mandible and adjuvant chemotherapy. Immunohistochemistry confirmed the diagnosis of small-cell carcinoma with neuroendocrine properties. The patient has been free of disease for 18 months after receiving treatment and was alive at the time of writing. We recommend surgical resection followed by chemotherapy for managing small-cell carcinomas in the mandibular region.

Utilization of a pre-bent plate-positioning surgical guide system in precise mandibular reconstruction with a free fibula flap.

OBJECTIVES: We evaluated the effects of three-dimensional virtual planning and the use of a plate-embedded surgical guide in mandibular reconstruction with microvascular fibula flaps. MATERIALS AND METHODS: We retrospectively reviewed 35 patients who underwent primary mandibular reconstruction with a free fibula flap. They were divided into three groups according to the therapy they received. In group A, 12 patients underwent reconstruction using the modified surgical guide system, including virtual surgeries, pre-bent titanium plates, screw-predesignated cutting guides for mandibular and fibular osteotomies, and plate-embedded shaping guides. In group B, 14 patients underwent reconstruction using the common surgical guide system, including virtual surgeries, cutting guides and pre-bent plates. In group C, 9 patients underwent reconstruction based on the surgeon's experience. All cases were reviewed for the total operative time, ischemia time of the fibula flaps, accuracy of surgery, and postoperative complications. RESULTS: All of the fibula flaps survived. In group A, the ischemia time was shorter than that of groups B and C (P < .05). The average gonion and condyle shift was lower in group A than in groups B and C (P < .01). CONCLUSIONS: Application of the screw-predesignated and plate-embedded surgical guide system can reduce the ischemia time and operation time in mandibular reconstruction with a fibula flap, and can increase reconstruction accuracy. This method is a precise and highly reliable technique for improving the clinical outcome of mandibular reconstruction.

[Tissue engineered bone reconstruction with modified PLGA/Type-I collagen compound scaffold].

OBJECTIVE: To fabricate bone grafts by bone marrow stromal cell combined with modified PLGA/Type-I collagen compound scaffold using tissue engineering method. METHODS: The modified PLGA/Type-I collagen compound scaffold was fabricated. The rabbit primary cultured osteoblasts were identified and seeded onto the modified compound scaffold for one week in vitro. The adhesion and growth of cells were observed with scanning electron microscope. The complex of cells and scaffold was implanted into the subcutaneous region of rabbits and new bone formation was evaluated. RESULTS: The rabbit bone marrow stromal cells were induced and differentiated into osteoblasts. The adhesion and growth of osteoblasts in cluster were observed on the surface of scaffolds. New bone formation was observed at one month postoperatively and active osteoblasts were found on the surface of the newly formed bone in vivo. CONCLUSION: The complex of PLGA and type-I collagen is an appropriate biodegradable scaffold and can be applied in bone tissue engineering.

[Experimental study on allogeneic mandible transplantation combined with basic fibroblast growth factor]

OBJECTIVE: To study the effect of basic fibroblast growth factor(b-FGF) on revascularization and bone remodeling of allogeneic mandible transplantation in repair of mandible defects in rabbits. METHODS: The mandible defects of 20 adult rabbits were created in both sides. The defects on the left side were implanted with allogeneic bone and local administration of b-FGF; the defects on the right side were only repaired with allogeneic bone as control group. At 1, 3 months after operation, the revascularization and bone remodeling were observed by ink-gelation vascular perfusion-transparency and histological examination. RESULTS: The allogeneic bone and b-FGF group had more marked vascularization and more quick and complete bone formation than control group. CONCLUSION: b-FGF can improve revascularization and bone formation after allogeneic mandible transplantation; allogeneic bone combined with b-FGF is a promising bone substitute in clinical uses.