Maxillary Defects Research Articles

Small molecule inhibitor of TGF-\u03b2 signaling enables robust osteogenesis of autologous GMSCs to successfully repair minipig severe maxillofacial bone defects

BackgroundClinically, for stem cell-based therapy (SCBT), autologous stem cells are considered better than allogenic stem cells because of little immune rejection and no risk of communicable disease infection. However, severe maxillofacial bone defects restoration needs sufficient autologous stem cells, and this remains a challenge worldwide. Human gingival mesenchymal stem cells (hGMSCs) derived from clinically discarded, easily obtainable, and self-healing autologous gingival tissues, have higher proliferation rate compared with autologous bone marrow mesenchymal stem cells (hBMSCs). But for clinical bone regeneration purpose, GMSCs have inferior osteogenic differentiation capability. In this study, a TGF-β signaling inhibitor SB431542 was used to enhance GMSCs osteogenesis in vitro and to repair minipig severe maxillofacial bone defects.MethodshGMSCs were isolated and cultured from clinically discarded gingival tissues. The effects of SB431542 on proliferation, apoptosis, and osteogenic differentiation of hGMSCs were analyzed in vitro, and then, SB431542-treated hGMSCs composited with Bio-Oss® were transplanted into immunocompromised mice subcutaneously to explore osteogenic differentiation in vivo. After that, SB431542-treated autologous pig GMSCs (pGMSCs) composited with Bio-Oss® were transplanted into circular confined defects (5 mm × 12 mm) in minipigs maxillary to investigate severe bone defect regeneration. Minipigs were sacrificed at 2 months and nude mice at 8 weeks to retrieve specimens for histological or micro-CT or CBCT analysis. Effects of SB431542 on TGF-β and BMP signaling in hGMSCs were investigated by Western Blot or qRT-PCR.ResultsOne micromolar of SB431542 treatment induced a robust osteogenesis of hGMSCs in vitro, without adverse effect on apoptosis and growth. In vivo, 1 μM SB431542 treatment also enabled striking osteogenesis of hGMSCs subcutaneously in nude mice and advanced new bone formation of pGMSCs in minipig maxillary bone defect model. In addition, SB431542-treated hGMSCs markedly increased bone-related proteins expression, and BMP2 and BMP4 gene expression. Conversely, SMAD3 protein-dependent TGF-β signal pathway phosphorylation was decreased.ConclusionsOur study show that osteogenic differentiation of GMSCs treated with TGF-β signaling inhibitor SB431542 was increased, and SB431542-treated autologous pig GMSCs could successfully repair minipig severe maxillofacial bone defects. This preclinical study brings about a promising large bone regeneration therapeutic potential of autologous GMSCs induced by SB431542 in clinic settings.

Biomechanical Evaluation of Zygomatic Implant Use in Patients With Different Buccal Maxillary Defect Levels.

The purpose of this study was to examine the biomechanics of zygomatic implants that were planned on an atrophic maxilla with five different buccal defect types and two different bone types. Three-dimensional models of zygomatic implants, human skulls, and maxillary prostheses were modeled with SolidWorks software. Ten finite element models of skulls with five different buccal defect types and two different bone types were constructed to mimic various clinical scenarios. Two bilateral zygomatic implants and two anterior dental implants were inserted into all models. The data were processed by ANSYS Workbench software. 150-N vertical occlusal and 300-N masseteric loads were simulated on a modeled prosthesis. The stresses on and deformations of the bones and implants were then observed and compared. Maximum Von Mises stress was found in skulls modeled with a type 4 defect and D3 bone type. Minimal stress values were found in the skull model with a type 1 buccal bone defect and D2 bone type. Displacement values were correlated with stress values. Cortical bone anchorage and bone type of zygomatic implants positively affect their biomechanics. Alveolar crest support has an effective role in the biomechanics of zygomatic implants.

Real-Time Navigation in Zygomatic Implant Placement: Workflow.

Zygomatic implant placement has been shown to be a reliable method to reconstruct severe maxillary atrophy and maxillary deficiency defects. The placement of zygomatic implants is more complex and more challenging than conventional oral implant placement especially in the quad approach. The application of navigation surgery in complex craniomaxillofacial procedures has become very helpful in transferring the surgical plan to the patient and avoiding adjacent anatomic injuries. This article shows the feasibility of real-time navigation in zygomatic implant placement via building a clear workflow.

Reconstruction of Bilateral Post-Traumatic Midfacial Defects Assisted by Three-Dimensional Craniomaxillofacial Data in Normal Chinese people—A Preliminary Study

To provide reference data for reconstruction of bilateral midfacial defects for which "mirror technique" cannot be applied. The present study included 4 patients (3 males and 1 female) with post-traumatic bilateral midfacial fractures and defects. The most similar model was retrieved from a database of 552 normal Chinese people and used to guide preoperative virtual surgery planning. All patients underwent open reduction, internal fixation, and reconstruction surgery in 1 stage. A custom-made titanium prosthesis was used to repair the defects of frontal and naso-orbital-ethmoid (NOE) region in 1 patient. Two fibular flaps were used to repair the maxillary defects. A deep circumflex iliac artery flap was used to reconstruct large midfacial defects involving the right zygoma. A surgical navigation system was applied in 3 patients. The 4 patients were followed for 6 to 42months. Two patients had finished all therapies and had satisfactory functional and cosmetic results. The appearance of 1 patient was obviously improved; that patient was still receiving treatment for denture prostheses. One patient had undergone first-stage reconstructive surgery and had normal occlusion at 6months of follow-up. For 3 patients whose treatment had been assisted by navigation, the average surgical deviation was less than 3mm (range, 1.5 to 2.2). For the patient whose treatment had not been assisted with navigation, the deviations differed in different areas: 3.47mm in the right zygomaticomaxillary complex, 5.48mm in the NOE area, and 5.91mm in the maxillary area. For patients with bilateral post-traumatic midfacial defects across the midline, the use of a 3-dimensional craniomaxillofacial database can be considered a feasible method for providing reference data for preoperative planning.

Sustained Release of Two Bioactive Factors from Supramolecular Hydrogel Promotes Periodontal Bone Regeneration

Intact and stable bone reconstruction is ideal for the treatment of periodontal bone destruction but remains challenging. In research, biomaterials are used to encapsulate stem cells or bioactive factors for periodontal bone regeneration, but, to the best of our knowledge, using a supramolecular hydrogel to encapsulate bioactive factors for their sustained release in bone defect areas to promote periodontal bone regeneration has not been reported. Herein, we used a well-studied hydrogelator, NapFFY, to coassemble with SDF-1 and BMP-2 to prepare a supramolecular hydrogel, SDF-1/BMP-2/NapFFY. In vitro and in vivo results indicated that these two bioactive factors were ideally, synchronously, and continuously released from the hydrogel to effectively promote the regeneration and reconstruction of periodontal bone tissues. Specifically, after the bone defect areas were treated with our SDF-1/BMP-2/NapFFY hydrogel for 8 weeks using maxillary critical-sized periodontal bone defect model rats, a superior bone regeneration rate of 56.7% bone volume fraction was achieved in these rats. We anticipate that our SDF-1/BMP-2/NapFFY hydrogel could replace bone transplantation in the clinic for the repair of periodontal bone defects and periodontally accelerated osteogenic orthodontics in the near future.

Outcomes of younger and older patients with palatal cancer undergoing facial-submental, artery island flap reconstruction of brown class ii maxillary defects after cancer ablation

Outcomes of younger and older patients with palatal cancer undergoing facial-submental, artery island flap reconstruction of brown class ii maxillary defects after cancer ablation

Simultalneous application of prefibricated strut member obturator prosthesis to the maxillary defect after ablative surgery to the nasal sinus malignant tumor --- a 10 years result

Simultalneous application of prefibricated strut member obturator prosthesis to the maxillary defect after ablative surgery to the nasal sinus malignant tumor --- a 10 years result

Transplantation of dental pulp-derived cell sheets cultured on human amniotic membrane induced to differentiate into bone.

The usefulness of the amniotic membrane as a cell culture substrate has led to its use in the development of dental pulp-derived cell sheets. We induced osteoblastic differentiation of dental pulp-derived cell sheets and conducted histological and immunological examinations in addition to imaging assessments for regeneration of bone defects. Dental pulp cells were obtained by primary culture of the dental pulp tissue harvested from extracted wisdom teeth. These cells were maintained for three to four passages. Subsequently, the dental pulp cells were seeded onto an amniotic membrane to produce dental pulp-derived cell sheets. Following the induction of osteoblastic differentiation, the sheets were grafted into the subcutaneous tissue of the lower back and maxillary bone defect of a nude mouse. Histological and immunological examinations of both grafts were performed. Dental pulp-derived cell sheets cultured on an osteoblast differentiation-inducing medium demonstrated resemblance to dental pulp tissue and produced calcified tissue. Mineralization was maintained following grafting of the sheets. Regeneration of the maxillary bone defect was observed. Induction of osteoblastic differentiation of the dental pulp-derived cell sheets may be indicated for the regeneration of periodontal tissue.

Combined Free Flap Reconstruction Following Head And Neck Cancer Resection: Chimeric And Double Free Flap Reconstruction


 
 
 
 Background: Head and neck reconstruction following cancer resection remains a challenge for surgeons. Microsurgical free tissue transfer is the technique of choice to close the defect. Extensive complex defects resulted from radical excision often require two free flaps to provide adequate bony structure and soft tissue coverage.
 Method: Three cases following head and neck cancer resection that require reconstruction with two combined free flaps were reported. The combination of two free flaps between vastus lateral free flap, radial forearm free flap, and free fibular flap was reviewed in this study. The patients were then followed up for 1-2 months.
 Result: Two of the patients had a flow through chimeric free flap between radial forearm free flap and free fibular flap to reconstruct the maxillary, palatal and mandibular defect. One patient had a combination of free fibular flap and vastus lateral free flap to reconstruct the mandibular defect. No complications were observed in all patients. All the flaps were vital without donor site morbidity. However, two patients needed secondary procedures for further reconstructions.
 Conclusion: Combined free flaps are reliable for closing the complex defect after wide resection of head and neck cancer. They can provide adequate tissues, reduce recipient site morbidity, permit simultaneous reconstruction with two-team approach. Therefore, provide a practical method of defect coverage for these patients.
 
 
 

Palatal fistulas complicating osseomyocutaneous reconstruction of oncological maxillectomy defects

Free flap reconstruction is the standard method for reconstructing large maxillary defects. Palatal fistula is an uncommon complication following reconstructive surgery. This study aims to describe the incidence, etiology, and management of palatal fistulae following reconstruction of oncological maxillectomy defects. A total of 108 patients from a single institution who underwent maxillectomy surgery between 2008 and 2014 were retrospectively reviewed. Ninety-two patients had resection of the hard palate. Sixty-eight patients underwent immediate free flap reconstruction of the palate; 55 had reconstruction of the hard palate with skin, and thirteen had reconstruction of the hard palate with muscle. The incidence of palatal fistulae in the reconstructed palates was 12% (11 patients) in this series: five after muscular reconstruction of the hard palate and six after cutaneous reconstruction. Muscular reconstruction of the hard palate is associated with a significantly higher incidence of palatal fistulae compared with cutaneous reconstruction (p = 0.015). The Cordeiro classification, smoking, diabetes, immunosuppression, and radiotherapy were not significant risk factors (p > 0.05). Based on our experience, we caution against attempting direct closure for established palatal fistulae, the majority of patients who had attempted direct closure of their fistulae failed to achieve resolution.

Cortical bone resorption of fibular bone after maxillary reconstruction with a vascularized fibula free flap: a computed tomography imaging study

This study was performed to evaluate the cortical bone resorption of fibular bone after maxillary reconstruction with a fibula free flap. A total of 35 patients with maxillary defects that were repaired using a fibula flap (62 fibula segments) between January 2011 and January 2016 were enrolled. Computed tomography (CT) images taken 1 week and 1 year postoperative were used to evaluate cortical bone resorption. The 62 fibula segments were measured on four different surfaces in the CT images. At 1 week, the thickness of the cortical bone was 2.57 ± 0.58 mm, 2.72 ± 0.46 mm, 3.84 ± 0.98 mm, and 4.36 ± 0.90 mm for the exterior, interior, superior, and inferior sides, respectively. At approximately 1 year, the cortical bone thickness was significantly reduced to 2.00 ± 0.65 mm (P < 0.01), 2.25 ± 0.60 mm (P < 0.01), 3.37 ± 0.90 mm (P < 0.01), and 2.96 ± 0.84 mm (P < 0.01) for the exterior, interior, superior, and inferior sides, respectively. The cortical bone thickness of fibular bone is significantly reduced 1 year after the restoration of maxillary defects with a fibula free flap, most significantly on the inferior side.

Prosthetic Treatment for Hemimaxillectomy Patient: (A Clinical Case)

Aims: prosthetic rehabilitation of a maxillary defect after hemi-maxillectomy with a palatal obturator made from nickel chromium framework. Materials and methods: A silicon impression was made and poured with a dental stone to develop a definitive cast. The site, position and shape of maxillary defect determine the path of insertion. Design the metal framework of the obturator to Class II R.P.D according to Kennedy's classification. Casting the framework in base-metal alloy made from nickel chromium framework, centric jaw relation was recorded. A finished prosthesis (an obturator of closed hollow-bulb type) was inserted. Conclusions: Obturator prosthesis enhancing function and speech, reduce the rate of fluids and food passing to the nose. Extend the border of an acrylic of the prosthesis at defect site lead to enhance both the retention and stability of the obturator.

Assessment of three dimensional bone augmentation of severely atrophied maxillary alveolar ridges using prebent titanium mesh vs customized poly-ether-ether-ketone (PEEK) mesh: A randomized clinical trial.

Alveolar bone grafting techniques and dental rehabilitation of patients with maxillary alveolar defects is a very challenging and costly procedure. Various methods have been described to reconstruct these defects in order to facilitate the placement of dental implants. The aim of this study was to assess three dimensional (3D) maxillary ridge augmentation using two innovative, accurate, and time saving protocols. Sixteen patients (32 implants) with vertically and horizontally deficient maxillary alveolar ridges, were equally allocated into 2 groups; a mix of particulate autogenous and xenogenic bone grafts loaded in a prebent titanium mesh (Control group) vs patient specific poly-ether-ether ketone meshes (Study group). Radiographic assessment was performed preoperatively, 1 week and 6 months postoperatively. Assessment included measurements of linear changes in the vertical and horizontal dimensions on cross sectional cuts of cone beam computed tomography using special software. Finally; the percentage of 3D bone gain in each group was compared to that of the other. Wound healing was uneventful for all cases except one patient in each group were the meshes were exposed 2 weeks' postsurgery. There was no statistical significance between both groups (P value = 0.2). Within the limitations of the sample size of this study, both techniques could be used as a successful method of ridge augmentation with no statistical significance between them.

Is a Maxillary Prosthesis More Useful than Surgical Reconstruction for Functional Recovery of Patients with Maxillary Defects？

Is a Maxillary Prosthesis More Useful than Surgical Reconstruction for Functional Recovery of Patients with Maxillary Defects？

Is Implant Therapy Effective for Functional Recovery of Patients with Maxillary Defect?

Is Implant Therapy Effective for Functional Recovery of Patients with Maxillary Defect?

Clinical Efficacy of Bioactive Glass in Combination with Platelet Rich Fibrin in Management of Gingival Recession Defects: A Prospective Comparative Study

Background: Various biomaterials have been employed along with Coronally advanced flap (CAF) in root coverage procedures. The combined efficacy of bioactive glass and Platelet rich fibrin in management of gingival recession needs to be evaluated. Aim: The aim of the present study was to clinically evaluate the efficacy of bioactive glass putty, platelet rich fibrin (PRF) and a combination of both in management of maxillary gingival recession defects. Materials and methods: 31 patients with 60 Millers class I/II recession defects were treated with one of the following interventions; GROUP I: CAF alone, GROUP II, III and IV: CAF+Bioactive glass, CAF+PRF,CAF+ Bioactive glass+PRF respectively Clinical parameters such as recession height (RH), recession width (RW), probing pocket depth (PPD), clinical attachment level (CAL), width of attached gingiva (WAG),keratinized tissue height (KTH) were evaluated at baseline for 6 months. Mean root coverage (RC%), changes in biotype, RES and VAS aesthetic scores evaluated at the end of 6 months intervals. Results: RH and RW showed statistically significant reduction from baseline to 6 months in all the groups (p ≤ 0.05). At the end of 6 months, the mean RC% was 61.0% ± 34.3%, 75.5% ± 25.9%, 67.2% ± 32.8% and 81.7% ± 28.6% in Group I, II, III and IV respectively. Intergroup analysis showed no statistically significant difference of parameters between groups at any time point. Conclusion: All the therapeutic interventions were effective in management of gingival recession defects. Though, group IV showed greater mRC% when compared to other groups, intergroup analysis failed to show any statistical significance.

Prosthetic reconstruction of maxillary defect resulting from a traumatic fall in an elderly patient: A case report

Prosthetic reconstruction of maxillary defect resulting from a traumatic fall in an elderly patient: A case report

The use of direct metal laser sintering technology in the management of acquired maxillofacial defects due to malignant neoplasm

Rehabilitation of maxillary defects presents a significant challenge in terms of restoration of near normal functions following the healing of large surgical wound. The obturator prostheses as a part of prosthetic management are used for the separation of oral and nasal cavities to allow adequate deglutition and articulation and support for the soft tissue to restore the midfacial contour in palatal defect cases. This clinical report describes a prosthetic approach to the rehabilitation of an acquired palatomaxillary defect with definitive obturator prosthesis as well as guide flange prosthesis for the management of mandibular deviation.

Restoring Skeletal Marker Points for Severe Maxillary and Mandibular Jaw Defects Using a Linear Regression Approach

For severe mandibular or maxillary defects across the midline, doctors often lack data on the shape of the jaws when designing virtual surgery. This study sought to repair the personalized 3-dimensional shape of the jaw, particularly when the jaw is severely damaged. Two linear regression methods, denoted method I and method II, were used to reconstruct key points of the severely damaged maxilla or mandible based on the remaining jaw. The predictor variable was the position of key points. Outcome variables were the position of key points and the error between the predicted and actual positions. Another variable was the average error. In the final data analysis, the effect of the method was judged based on the mean error and error probability distribution. Computed tomographic data of jaws from 44 normal adults in East China were collected over 2years by the Shanghai Jiao Tong University School of Medicine (Shanghai, China). Sixteen 16 key points were extracted for each jaw. Method I showed that 2-dimensional regression can yield the best overall result and that the position error of most points can be decreased to smaller than 5mm. The result of method II was similar to that of method I but showed cumulative errors. Linear regression can be used to locate key points. Two-dimensional regression has the best effect, which can be used as a reference to develop a surgical plan and perform surgery.

Microstructured beta-tricalcium phosphate for alveolar cleft repair: a two-centre study

The current standard of care in alveolar cleft repair is timing the procedure in the mixed dentition stage and making use of autologous bone to restore the maxillary defect. Using a synthetic bone substitute bypasses the risk of donor site morbidity and reduces the operation time. In this study, the outcome of alveolar cleft repair using microporous beta-tricalcium phosphate (β-TCP) was investigated in patients with unilateral cleft lip and palate. Twenty patients were enrolled prospectively in this study, divided between two centres. Continuity of the alveolar process, recurrence of oronasal fistulas, and eruption of teeth into the repaired cleft were evaluated at 1year postoperative. Also, cone beam computed tomography scans were analyzed using a volume-based semi-automatic segmentation protocol. No adverse events were reported. The mean residual bone volume in the repaired cleft at 1year postoperative was 65%. There was no recurrence of oronasal fistula. Furthermore, 90% of the teeth adjacent to the cleft erupted spontaneously and all patients showed a continuous alveolar process. Secondary alveolar grafting using microporous β-TCP can safely be used in the clinical situation. Residual calcified tissue, canine eruption, and complication rates at the recipient site are comparable to those with autologous grafts.