Reconstruction of mandibular defects - clinical retrospective research over a 10-year period -

Augmented reality-guided osteotomies for simulated mandibular reconstruction with fibular bone using virtual cutting guides and 3D navigation

In the last decades, maxillomandibular reconstruction has been revolutionised by the use of free flaps and virtual surgical planning technologies. However, the currently available applied physical cutting guides provide no intraoperative flexibility, and adjustments based on intraoperative findings are not possible. A novel augmented reality (AR)-guided technique is presented that allows for quick intraoperative surgical planning adaptations. A mandibular reconstruction using fibular bone was simulated and an application for Microsoft's HoloLens 2 developed for modelling the fibular segments. The application provided real-time feedback on the position of the saw with respect to the virtual planned osteotomy planes projected on the fibular bone. The technique was investigated in a validation test using 3-dimensional printed fibular models. Mean (SD) deviations from the planned osteotomy plane, expressed in degrees and segment length deviation, were 4.1° (2.6) and 2.0 mm (1.1), respectively, for session one, and 3.1° (2.3) and 2.3 mm (1.4), respectively, for session two. The feasibility of the AR-guided technique to perform osteotomies of fibular bone was established in this workflow simulation. The technique can improve the transfer of the preoperative plan to the intraoperative situation. Further development is, however, necessary since conventional cuttings guides are, so far, superior.

Analysis of condylar positioning in the temporomandibular joint following mandibular reconstruction: Introduction of a new classification system and assessment of influencing factors on displacement

OBJECTIVE

This study investigates the unsatisfactory outcomes observed in mandibular reconstruction procedures attributed to improper condylar positioning in the Temporomandibular Joint. It also proposes a systematic classification for post-reconstruction condylar positioning dissatisfaction.

METHODS

A retrospective analysis was conducted on 337 patients who underwent tumor removal and mandibular reconstruction with vascularized osteocutaneous flaps. Reconstruction techniques included conventional surgery (43.3%) and 3D technology-guided procedures (56.7%). Evaluation utilized preoperative and postoperative CT scans to assess mandibular vertical ramus length (V) and condylar alignment in both sagittal (S) and coronal (C) planes. Accordingly, a classification system for condylar positioning was developed and abbreviated as VSC. It includes four classes: Class I, proper condylar reconstruction; Class II, short ramus length; Class III, one or two aspects of sagittal/coronal condylar positions dissatisfaction; and Class IV, two or three aspects dissatisfaction.

RESULTS

The overall success rate for condylar reconstruction was 85.16%. Though not statistically significant, the success rate was marginally higher in the 3D-assisted group (85.86%) compared to the conventional group (84.25%). In terms of the VSC classification, the distribution of cases across Class I, II, III, and IV were 287, 4, 9, and 37 cases, respectively. Notably, condylar dislocation was significantly associated with the defect site, particularly the body and condyle (p < 0.001, OR = 49.734, 95% CI 12.995-190.342), and the number of reconstructed segments (p = 0.025, OR = 3.480, 95% CI 1.173-10.328).

CONCLUSION

The findings highlight the importance of accurate reconstruction methods and reveal implications of the defect site and the number of reconstructed segments in condylar dislocation. Consequently, we propose a classification system to refine condylar positioning assessment and enhance surgical outcomes in mandibular reconstruction.

Complications in Deep Circumflex Iliac Artery-Related Vascularized Free Iliac Flap

BACKGROUND

Since its first application in 1978, the vascularized free iliac flap (VFIF) has gradually become a mainstay for tissue defect reconstruction. However, the complications associated with harvesting the bone flap and its corresponding reconstruction surgery cannot be overlooked.

METHODS

We conducted a narrative review through literature search to identify the types, incidence, influencing factors, measurement methods, and treatment approaches of complications related to DCIA-related VFIF.

RESULTS

We propose the "LIP" rule (Loss, Injury, Postoperative) for classifying donor site complications. For the four most common recipient sites, mandible, maxilla, extremities, and hip joint, we list the common and rare complications that may occur. Additionally, we provide a summary of the methods and advances in preventing these complications.

CONCLUSIONS

We comprehensively describe the complications observed in the application of DCIA-related VFIF and introduce the "LIP" principle and other strategies to minimize or avoid adverse outcomes.

Evaluation of zirconia implants in fibula and deep circumflex iliac artery flaps: a prospective 1.5-year follow-up study

OBJECTIVES

Follow-up results of modern zirconia implants inserted in fibula free and deep circumflex iliac artery (DCIA) flaps with fixed dentures are scarce. This study aimed to evaluate crestal bone changes and the survival rate of zirconia implants for up to 1.5 years of prospective follow-up.

MATERIALS AND METHODS

Ten patients with six fibula and four DCIA flaps underwent reconstruction in the lower and upper jaws using vascularized composite flaps and were treated with zirconia implants. Peri-implant bone resorption was measured using radiographic images that were taken immediately after implant surgery (T1) and after three (T2), 12 (T3), and 18 months (T4).

RESULTS

Between the day of operation and T3, a significant increase in distance was recorded for the fibula flaps. After occlusal loading (T2) of 41 zirconia implants for up to 1.5 years, no significant bone loss in each flap was observed overall. An overall survival rate of 96.56% was reported.

CONCLUSIONS

When comparing both composite flaps, no significant difference in periimplant bone levels was measured between the same timepoints.

CLINICAL RELEVANCE

For fixed dentures, modern zirconia implants can be used in the DCIA and fibula flaps, however further long-term data is necessary.

Volumetric analysis of spontaneous bone formation after segmental mandibulectomy in patients with MRONJ

OBJECTIVE

The purpose of this study was to quantify the spontaneous new bone formation and bony bridge formation by 3-dimensional analysis of cone-beam computed tomography (CBCT) after segmental mandibulectomy reconstruction using an R-plate without any graft material in patients with medication-related osteonecrosis of the jaw (MRONJ).

STUDY DESIGN

15 MRONJ patients (13 females and 2 males) were selected based on the inclusion criteria. Data on new bone formation, bony bridge formation, R-plate fracture, patient age, and type and duration of medication were collected. Panoramic and CBCT scans were obtained at 1 day, 6, 12, and 24 months postoperatively. CBCT images of each period were transferred to a personal computer using MIMICS 21.0 for volumetric analysis. After quantifying the volume of new bone formation, we calculated the percentage of the volume of new bone to the segmentally resected necrotic bone volume (%NB).

RESULTS

All patients showed spontaneous new bone formation with the average of 20.69% within a year and 28.52% within 2 years, and 80.0% showed bony bridge formation within a year.

CONCLUSIONS

The R-plate reconstruction in patients with MRONJ showed significant amount of spontaneous new bone formation within 2 years after segmental mandibulectomy.

Postoperative volume maintenance rate of microvascular free flap in oral and maxillofacial region: Systematic review and meta-analysis

BACKGROUND AND OBJECTIVES

The resorption of flap's volume can be frequently observed in the transplantation of microvascular free flaps, which could significantly affect postoperative function. Therefore, it's essential to comprehend the postoperative flap volume and the mechanisms behind before making clinical decisions.

METHODS

Literature search was conducted from database on PubMed, EMBASE, Cochrane Library, Chinese database and Google Scholar. A random effects model meta-analyses and descriptive systematic review were performed.

RESULTS

The search identified 420 articles, of which 9 studies included in meta-analysis and 14 studies included in descriptive systematic review. Postoperative flap volume maintenance rate is used to represent the volume change. The pooled mean postoperative flap volume maintenance rate was 62.82 % for soft tissue flap (95 %CI: 58.83 to 66.82, p = 0.076, I2=56.3 %) and 85.96 % for bone flap (95 %CI: 84.19 to 87.73, p = 0.274, I2=20.4 %). Weight loss, muscle atrophy, and decreased serum albumin levels are risk factors for postoperative volume reduction of soft tissue flaps. The bone resorption rate of bone flaps in women is higher than that in men.

CONCLUSION

When designing microvascular free flaps for oral and maxillofacial surgery, soft tissue flaps should consider an anticipated postoperative shrinkage of 37 %, while bone flaps should consider an anticipated postoperative shrinkage of 14 %.

In vitroosteogenesis of hMSCs on collagen membranes embedded within LEGO®-inspired 3D printed PCL constructs for mandibular bone repair

The field of bone tissue engineering aims to develop an effective and aesthetical bone graft substitute capable of repairing large mandibular defects. However, graft failure resulting from necrosis and insufficient integration with native tissue due to lack of oxygen and nutrient transportation remains a concern. To overcome these drawbacks, this study aims to develop a 3D printed polycaprolactone layered construct with a LEGO®-inspired interlocking mechanism enabling spatial distribution of biological components. To highlight itsin vitroosteogenic potential, human mesenchymal stromal cells are cultured onto Bio-Gide®Compressed collagen (Col) membranes, which are embedded within the layered construct for 28 d. The osteogenic response is assessed through the measurement of proliferation, relevant markers for osteogenesis including alkaline phosphatase (ALP) activity, expression of transcriptional genes (SP7, RUNX2/SOX9) as well matrix-related genes (COL1A1, ALPL IBSP, SPP1), osteoprotegerin secretion.In vitroosteogenic differentiation results showed increased levels of these osteogenic markers, indicating the layered construct's potential to support osteogenesis. In this study, a novel workflow of 3D printing a patient-specific LEGO®-inspired layered construct that can spatially deliver biological elements was successfully demonstrated. These layered constructs have the potential to be employed as a bone tissue engineering strategy, with particular focus on the repair of large mandibular defects.

Digital Implant-Supported Restoration Planning Placed in Autologous Graft Using Titanium Implants Produced by Additive Manufacturing

This clinical report presents a technique to reconstruct extensively resected mandibles using a combination of autologous bone grafts and additive manufacturing techniques. Mandibular defects, often arising from trauma, tumors, or congenital anomalies, can severely impact both function and aesthetics. Conventional reconstruction methods have their limitations, often resulting in suboptimal outcomes. In these reports, we detail clinical cases where patients with different mandibular defects underwent reconstructive surgery. In each instance, autologous grafts were harvested to ensure the restoration of native bone tissue, while advanced virtual planning techniques were employed for precise graft design and dental implant placement. The patients experienced substantial improvements in masticatory function, speech, and facial aesthetics. Utilizing autologous grafts minimized the risk of rejection and complications associated with foreign materials. The integration of virtual planning precision allowed customized solutions, reducing surgical duration and optimizing implant positioning. These 2 cases underscores the potential of combining autologous grafts with virtual planning precision and dental implants produced by additive manufacturing for mandible reconstruction.

The Reconstruction of Mandible Defects in War Injuries: Systematic Review and Meta-Analysis

Study Design

Systematic Review and Meta-Analysis.

Objective

There has been an increasing trend in maxillofacial injuries associated with combat trauma. Within the maxillofacial complex, the mandible is the most likely structure to be damaged during combat. The structural deficits as a result can be reconstructed with many options. These include vascularised bone grafts (VBGs), non-vascularised bone grafts (NVBGs), alloplastic implants, reconstruction bars and distraction osteogenesis. This study aimed to determine the common modality and efficacy of mandibular reconstruction in combat trauma-related defects.

Methods

A literature search was conducted on Pubmed, Prospero, Dynamed, DARE, EMBASE, COCHRANE and BMJ databases.

Results

A total of six articles met the inclusion criteria identifying 165 patients requiring mandibular reconstruction. Non-vascularised iliac bone graft (n = 137) was the most common method followed by ileac crest bone chips harvest using Dacron urethran osteomesh tray (n = 24) and frontoparietal grafts (n = 4). Meta-analysis of five out of six trials demonstrated an overall success rate of 85% (95% CI 79-90; I2 = 59%). A total of 13% (n = 22) of reconstructions failed either completely or partially and 21% (n = 34) of patients suffered postoperative complications.

Conclusions

NVBGs are a practical, cost-effective and favourable method of war zone management of mandibular defects with success rates comparable to those reported in the civilian literature. However, general trauma principles take precedence to rule out life-threatening injuries. Due consideration of patient factors, surgical factors, and available resources are required in the first-line management of combat-related mandibular defects.

Rehabilitation of mandibular resected patients using fixed immediately loaded corticobasal implant -supported prostheses. A case series

INTRODUCTION AND IMPORTANCE

Aliments such as congenital conditions, pathological, and iatrogenic circumstances may result in mandibular defects that can severely disturb the patients' oral health, functions (mastication, speech), aesthetics, and quality of life and present a rehabilitating challenge.

CASE PRESENTATION

we present a multidisciplinary treatment approach for three cases presented with mandibular resection as a consequence of cystic, benign, and malignant tumour eradication that were rehabilitated with immediately loaded fixed corticobasal implant-supported prostheses and a follow-up period of 5,5 and 4 years. The reported cases present with excellent implant survival, along with healthy peri-implant tissues, stable prostheses, enhanced speech, chewing ability, aesthetics, superior patient satisfaction, and improved overall self-esteem.

CLINICAL DISCUSSION

A multidisciplinary oral and maxillofacial team is mandatory for the successful rehabilitation of patients with mandibular resection and to restore soft and hard tissue loss. The reported treatment modality offers the patient immediate fixed implant-supported prostheses omitting the need for a bone grafting procedure, with optimum peri-implant tissue health, excellent biomechanical and prosthetic results, and significant improvement in function and satisfaction.

CONCLUSION

Corticobasal fixed implant-supported prostheses can be a reliable treatment modality for mandibular resection, resulting in notable enhancements in the patients' oral health, appearance, mastication, speech, and self-esteem.

Poor condyle position after mandibular reconstruction and a classification system for patients with "VSCU" based on computed tomography: a cross-sectional study with retrospective data collection

Background

Although the application of vascularized free bone muscle flap to reconstruct the mandible has become a standardized approach for mandible reconstruction, the results of its reconstruction are not always satisfactory. The purpose of this study was to identify the types of mandibular and condylar defects by analyzing the unsatisfactory cases of mandibular reconstruction in clinical practice, and to provide some clinical experience of reconstruction.

Methods

Our study retrospectively analyzed 364 patients who underwent mandibular resection and vascularized free bone flap reconstruction of the mandible and temporomandibular joint (TMJ). We innovatively proposed a "VSCU" classification system (V: vertical position, S: sagittal position, C: coronal position, U: condylar resection is not required) by analyzing computed tomography (CT) scans of mandibular branches and TMJs.

Results

In all, 221 cases of free iliac muscle flap and 143 cases of fibula muscle flap were included in this study, of which 23 cases had unsatisfactory results after TMJ reconstruction. We classified 23 patients with unsatisfactory mandibular reconstruction according to the "VSCU" classification system. The most common type was U + V + SfC (n=8), followed by V - SfC + U + (n=4), V - s + C + U + (n=3), V - sbcou - (n=3), V - SBC + U + (n=2), V - s + C + U - (n=1). The most common classification was insufficient mandibular rami length, followed by condylar sagittal anteriorization. There was no significant change in the position of condyle on the healthy side during mandibular reconstruction involving condyle. P1 on the affected side was 52.28±4.17 mm before operation and 58.94±5.65 mm after operation, P<0.01; P2 was 12.83±3.49 mm before operation and 24.90±7.15 mm after operation. S2 was 4.54±2.84 mm before operation and 19.10±8.54 mm after operation. A2 was 11.46±3.35 mm before operation and 24.15±8.29 mm after operation. The P values were all less than 0.01, and the differences were statistically significant.

Conclusions

We propose to use the "VSCU" classification system for accurate 3-dimensional (3D) analysis and positioning, and then obtain accurate models through computer-aided design and manufacturing (CAD/CAM), which can reduce the occurrence of poor reconstruction effect and unreasonable joint position, and is worthy of clinical promotion.

Dental Implant Placement in the Maxilla Following Ridge Augmentation with Free Iliac Bone Graft and Oral Rehabilitation with Fixed Prosthesis: a Three-Year Follow-Up Study

Objectives

This prospective follow-up study aimed to evaluate the stability values of tapered titanium implants inserted into maxilla following ridge augmentation with free iliac bone graft and crestal bone changes up to three years of follow-up.

Material and Methods

A total of seven patients with 34 tapered titanium implants in the maxilla with fixed protheses were enrolled in this prospective follow-up study. Patients with previously augmented maxillae using free iliac bone grafts were included. Implant stability was measured (Osstell™) for up to three months of healing. Peri-implant bone resorption was measured using radiographic images taken immediately after implant surgery and after three years. Using a clinical and radiological examination survival and success rates were evaluated.

Results

After implant insertion, the stability was 60.93, whereas the stability increased significantly (P = 0.0192) to 64.97 at implant exposure (after 3 months). The mean bone loss around the implants was 1.13 mm after three years. Clinical parameters revealed a mean sulcus depth of 2.76 (1.18) mm and a bleeding on probing score of 0.29 (0.58). The survival rate was 100%, and the success rate was 67.65% at the end of the study.

Conclusions

Tapered implants can be used in free iliac bone grafts for fixed dentures. Implant stability values were high after insertion. In terms of a success rate of 67.65%, the patient's jaw reconstruction indicated a reduced implant success when comparing the data with healthy patients without any augmentation procedures.

Osteoinductive and Osteogenic Capacity of Freeze-Dried Bovine Bone Compared to Deproteinized Bovine Bone Mineral Scaffold in Human Umbilical Cord Mesenchymal Stem Cell Culture: An In Vitro Study

OBJECTIVE

 Freeze-dried bovine bone scaffold (FDBB) or decellularized FDBB (dc-FDBB) was developed as an ideal scaffold with osteoinductive properties. This research aims to compare the osteoinductive properties marked by the expression of runt-related transcription factor-2 (RUNX2) and Osterix (OSX) and the osteogenic capacity of these scaffolds imbued with human umbilical cord mesenchymal stem cells (hUCMSCs).

MATERIALS AND METHODS

 This study was performed in five experimental groups: a negative control group (C-) of hUCMSCs with a normal growth medium, a positive control group (C + ) of hUCMSCs with an osteogenic medium, experimental group 1 (E1) with an FDBB conditioned medium (CM), and experimental group 2 (E2) with a dc-FDBB-CM, and a third experimental group (E3) consisting of a DBBM-CM. Alizarin red staining was performed to qualitatively assess osteoinductive capacity. RUNX2 and OSX expression was quantified using real-time quantification polymerase chain reaction with two replications on day six (D6) and day 12 (D12) as fold changes.

RESULTS

 This experiment revealed that hUCMSCs were positively expressed by CD73, CD90, and CD105 but were not expressed by CD34. Alizarin red staining showed that E1 had the most calcium deposition on D6 and D12, followed by E3 and then E2 The RUNX2 and OSX expression was higher in E1 but this difference was not significant. The OSX expression in E1,E2,E3 was lower on D12 and C+ of OSX had the highest expression. There was a significant difference of fold change measured between all groups (p < 0.05), and there was no significant difference between any of the groups treated with OSX and RUNX2 on D6 and D12.

CONCLUSION

 FDBB osteoinduction and osteogenic capacity were higher when compared with DBBM and dc-FDBB.

Micro-porous PLGA/β-TCP/TPU scaffolds prepared by solvent-based 3D printing for bone tissue engineering purposes

The 3D printing process of fused deposition modelling is an attractive fabrication approach to create tissue-engineered bone substitutes to regenerate large mandibular bone defects, but often lacks desired surface porosity for enhanced protein adsorption and cell adhesion. Solvent-based printing leads to the spontaneous formation of micropores on the scaffold's surface upon solvent removal, without the need for further post processing. Our aim is to create and characterize porous scaffolds using a new formulation composed of mechanically stable poly(lactic-co-glycol acid) and osteoconductive β-tricalcium phosphate with and without the addition of elastic thermoplastic polyurethane prepared by solvent-based 3D-printing technique. Large-scale regenerative scaffolds can be 3D-printed with adequate fidelity and show porosity at multiple levels analysed via micro-computer tomography, scanning electron microscopy and N2 sorption. Superior mechanical properties compared to a commercially available calcium phosphate ink are demonstrated in compression and screw pull out tests. Biological assessments including cell activity assay and live-dead staining prove the scaffold's cytocompatibility. Osteoconductive properties are demonstrated by performing an osteogenic differentiation assay with primary human bone marrow mesenchymal stromal cells. We propose a versatile fabrication process to create porous 3D-printed scaffolds with adequate mechanical stability and osteoconductivity, both important characteristics for segmental mandibular bone reconstruction.

Tenants of Mandibular Reconstruction in Segmental Defects

The premises of mandibular reconstruction are the restoration of occlusion and mandibular contour for the purpose of preserving the facial identity, oral airway, and effective speech and mastication. Establishing functional occlusion is the primary tenant in all mandibular reconstruction. In cases of segmental defects, particularly in dentate regions of the mandible, there has been a paradigm shift over the past two decades in how surgeons are approaching the restoration of load-bearing mandibular continuity with capacity for dental implantation. Here we discuss considerations for deciding the most effective method of reconstruction in segmental defects.

Bone formation ability of Gli1+ cells in the periodontal ligament after tooth extraction

During the process of socket healing after tooth extraction, osteoblasts appear in the tooth socket and form alveolar bone; however, the source of these osteoblasts is still uncertain. Recently, it has been demonstrated that cells expressing Gli1, a downstream factor of sonic hedgehog signaling, exhibit stem cell properties in the periodontal ligament (PDL). Therefore, in the present study, the differentiation ability of Gli1⁺-PDL cells after tooth extraction was analyzed using Gli1-Cre^ERT2/ROSA26-loxP-stop-loxP-tdTomato (iGli1/Tomato) mice. After the final administration of tamoxifen to iGli1/Tomato mice, Gli1/Tomato⁺ cells were rarely detected in the PDL. One day after the tooth extraction, although inflammatory cells appeared in the tooth socket, Periostin⁺ PDL-like tissues having a few Gli1/Tomato⁺ cells remained near the alveolar bone. Three days after the extraction, the number of Gli1/Tomato⁺ cells increased as evidenced by numerous PCNA⁺ cells in the socket. Some of these Gli1/Tomato⁺ cells expressed BMP4 and Phosphorylated (P)-Smad1/5/8. After seven days, the Osteopontin⁺ bone matrix was formed in the tooth socket apart from the alveolar bone. Many Gli1/Tomato⁺ osteoblasts that were positive for Runx2⁺ were arranged on the surface of the newly formed bone matrix. In the absence of Gli1⁺-PDL cells in Gli1-Cre^ERT2/Rosa26-loxP-stop-loxP-tdDTA (iGli1/DTA) mice, the amount of newly formed bone matrix was significantly reduced in the tooth socket. Therefore, these results collectively suggest that Gli1⁺-PDL cells differentiate into osteoblasts to form the bone matrix in the tooth socket; thus, this differentiation might be regulated, at least in part, by bone morphogenetic protein (BMP) signaling.

Regenerative Potential of Hydroxyapatite-Based Ceramic Biomaterial on Mandibular Cortical Bone: An In Vivo Study

Reconstruction of bone defects and maintaining the continuity of the mandible is still a challenge in the maxillofacial surgery. Nowadays, the biomedical research within bone defect treatment is focussed on the therapy of using innovative biomaterials with specific characteristics consisting of the body’s own substances. Hydroxyapatite ceramic scaffolds have fully acceptable phase compositions, microstructures and compressive strengths for their use in regenerative medicine. The innovative hydroxyapatite ceramics used by us were prepared using the tape-casting method, which allows variation in the shape of samples after packing hydroxyapatite paste to 3D-printed plastic form. The purpose of our qualitative study was to evaluate the regenerative potential of the innovative ceramic biomaterial prepared using this method in the therapy of the cortical bone of the lower jaw in four mature pigs. The mandible bone defects were evaluated after different periods of time (after 3, 4, 5 and 6 months) and compared with the control sample (healthy cortical bone from the opposite side of the mandible). The results of the morphological, clinical and radiological investigation and hardness examination confirmed the positive regenerative potential of ceramic implants after treatment of the mandible bone defects in the porcine mandible model.

An Analysis of the Viability of Nonvascular Iliac and Fibula Grafts in Mandibular Reconstruction in Patients with Circulatory Diseases: A Prospective Randomized Study

Vascularized bone grafts are considered as the gold standard for mandibular reconstruction. However, there are certain limitations of them, such as they are contraindicated in patients with circulatory disturbances. Therefore, Non-vascular bone grafts become the viable option for reconstruction. Our study aims to prospectively compare the long-term viability of avascular iliac and fibula bone grafts in the reconstruction of mandibular defects. Objectives were to evaluate the difficulty in swallowing, mastication, speech problems, infection, wound dehiscence, restricted limb movement, and altered gait among the iliac and fibula group. A total of 14 patients, planned for the reconstruction of mandibular defects from 2016 to 2018 were randomly allocated into two groups; nonvascular iliac and fibula graft groups. Clinical assessment for improvement in function, esthetics, wound healing, pain, and donor site morbidity was done and was followed up for one year. Digital orthopantomogram was taken for radiographic evaluation for up to one year. Difficulty in swallowing, mastication, speech, infection, restricted limb movement, and altered gait was statistically significant and was seen more in the fibula group. Wound dehiscence with graft exposure was found in one subject. The overall success rate was 100% in the iliac group and 85.7% in the fibula group. Considering the long-term complications and success rate, the nonvascular iliac graft was found to be superior and can be used as an alternative to a nonvascular fibula graft for a defect length up to 7 cm.

Analysis of Dental Implant Rehabilitation in the Reconstructed Jaw by Deep Circumflex Iliac Artery Flap, a Retrospective Study

The purpose of this study is to analyze the clinical results of the implant rehabilitation for a jaw reconstructed by the deep circumflex iliac artery (DCIA) flap. A total of 13 patients were included in this study from 2010 to 2020. Medical records were collected retrospectively and analyzed. The mandible was involved in 10 cases and the maxilla was in 3 cases. The average width of the DCIA flap was 8.6 mm, and the height was 20.65 mm. A total of 41 dental implants with a diameter of 3.9–5.0 mm and a length of 10.0–11.5 mm were placed at an average of 12.3 months after the reconstruction. The average follow-up period after delivering a permanent prosthesis was 15 months (range, 2 to 51 months) and the overall mean follow-up period was 48 months. In all, 3 implants of the total 41 implants were removed. The DCIA flap is the most suitable for reproducing the original contour of the original jawbone compared with the fibular flap. In addition, the height and width of the reconstructed bone is appropriate for implant placement, which is advantageous for the rehabilitation of oral function and aesthetics using the implant.

Clinically relevant preclinical animal models for testing novel cranio-maxillofacial bone 3D-printed biomaterials

Bone tissue engineering is a rapidly developing field with potential for the regeneration of craniomaxillofacial (CMF) bones, with 3D printing being a suitable fabrication tool for patient-specific implants. The CMF region includes a variety of different bones with distinct functions. The clinical implementation of tissue engineering concepts is currently poor, likely due to multiple reasons including the complexity of the CMF anatomy and biology, and the limited relevance of the currently used preclinical models. The 'recapitulation of a human disease' is a core requisite of preclinical animal models, but this aspect is often neglected, with a vast majority of studies failing to identify the specific clinical indication they are targeting and/or the rationale for choosing one animal model over another. Currently, there are no suitable guidelines that propose the most appropriate animal model to address a specific CMF pathology and no standards are established to test the efficacy of biomaterials or tissue engineered constructs in the CMF field. This review reports the current clinical scenario of CMF reconstruction, then discusses the numerous limitations of currently used preclinical animal models employed for validating 3D-printed tissue engineered constructs and the need to reduce animal work that does not address a specific clinical question. We will highlight critical research aspects to consider, to pave a clinically driven path for the development of new tissue engineered materials for CMF reconstruction.

Utilization of non-vascularized bone graft with regional flap as an alternative for facial reconstruction

Mandibular resections decision is one of the most important steps in oral cavity malignant or nonmalignant lesions associated with the mandible. The role of mandibular reconstruction is not only for cosmesis, but it is also indicated for functional rehabilitation such as swallowing, phonetics, and for facial symmetrical. Even though the free tissue transfer is considered a gold standard for mandibular reconstruction, the importance of nonvascularized bone grafts (NVBGs) such as fibula, calvarium, rib, sternum, and iliac are still persisting in mandibulectomies condition like patient who have not taken radiotherapy or not willing to undergo radiotherapy or not fit for free tissue transfer and provides a good contour of mandibular replacement. The success rate of NVBG depends upon patient selection, preoperative planning, and meticulous nursing care. Addition to NVBG, regional flaps such as pectoralis major myocutaneous (PMMC) flap will help in soft-tissue replacement of the defect as well as it will help in the situation where primary closure and airtight closure is not possible. This case report will discuss in detail about the management of anterior segmental mandibulectomy due to oncological resection and reconstruction with NVBG with fibula and PMMC.

Establishing a Novel Treatment Algorithm for Pediatric Mandibular Tumor Reconstruction

INTRODUCTION

Guidelines for pediatric mandibular reconstruction (PMR) are not well-established. One must consider the growing craniofacial skeleton, mixed dentition, long-term dental occlusion, need for secondary reconstruction, and speech development. The traditional guideline (bone defect > 5 cm) for use of vascularized bone grafts (VBG) is not applicable given the variation of pediatric mandibular size and growth. We seek to propose a novel algorithm for PMR.

MATERIALS AND METHODS

An Institutional Review Board approved retrospective review of patients who underwent PMR for tumor resections between 2005 and 2019 evaluated patients' demographics, complications, resection index (RI) (resection length to mandibular length), and surgical outcomes. Outcomes based on RI were analyzed to establish guidelines for VBG utilization.

RESULTS

Twenty-four patients underwent PMR at a mean age of 9.1 years (range: 1-18). The mandibular defect (mean ± standard deviation) for non-VBG (n = 18) and VBG (n = 6) was 6.6 ± 3.0 cm and 12.8 ± 4.3 cm, respectively. The VBG group had fewer return trips to the operating room (P = 0.028) and fewer major complications (P = 0.028). When non-VBG with RI > 32% were compared to <32%, there was statistically less returns to the operating room for complications and a lower rate of early (<30 days) major complications.

DISCUSSION

Our algorithm proposes an RI cutoff of 32% for VBG use for PMR. Patients with a sizable soft tissue defect, previous chemotherapy and/or radiation, planned adjuvant chemotherapy and/or radiation therapy, or a history of failed non-VBG should undergo reconstruction using VBG.

Mandibular rehabilitation: From the Andy Gump deformity to jaw-in-a-day

The mandible is a critical structure of the lower facial skeleton which plays an important role in several vital functions. Segmental resection of the mandible is at times required in patients with advanced oral cavity malignancies, primary mandibular tumors, and radiation or medication induced osteonecrosis. Mandibulectomy can significantly decrease quality of life, and thus mandibular reconstruction is an important aspect of the operative plan. Mandibular reconstruction is challenging due to the complex three-dimensional anatomy of the mandible, and the precision required to restore dental occlusion in dentate patients. Significant advances have been made over the past decade in the ability to reconstruct and rehabilitate patients after a segmental mandibulectomy. This review will highlight these advances and discuss the timing of dental implantation.

The application of chimeric deep circumflex iliac artery perforator flap for oromandibular reconstruction: A case report

RATIONALE

The free fibular flap is considered the gold standard, particularly for a mandibular defect combined with a significant soft tissue defect. However, the fibular flap has the disadvantages of a lack of height for postoperative dental restoration and donor site skin graft if the skin paddle is wider than 5 cm. The larger bone and soft tissue defects tend to be reconstructed using either a scapula or a combination of iliac artery and radial free flap. Few cases involving reconstruction using chimeric deep circumflex iliac artery perforator flap (DCIAPF) for mandibular defect combined with more significant soft tissue defects have been reported due to perforator variations. We successfully performed oromandibular reconstruction using chimeric DCIAPF.

PATIENT CONCERNS

A 56-year-old male patient was admitted due to "constant pain in the gradually enlarged right lower gingival mass since the previous four months." The patient had no other obvious symptoms, and no history of diabetes or hypertension was reported. The patient reported long-term smoking and drinking habits.

DIAGNOSES

Computed tomography (CT) revealed a neoplasm in the right buccal space, which is primarily considered a malignancy. The pathological results of a gingival mass biopsy presented squamous cell carcinoma.

INTERVENTIONS

No operative contraindications were confirmed after regular tests and examinations were undertaken. The patient underwent a primary extent resection of a 6-cm-long mandible, including mass and suprascapulohyoid neck dissection. The oromandibular defects were then reconstructed with chimeric DCIAPF, simultaneously using the iliac crest bone flap to repair the mandibular lateral segment defect and the skin paddle to repair the intraoral soft tissue defect of 5 × 10 cm.

OUTCOMES

The total operating time was five and half hours and blood loss was approximately 500 ml. The operation was successful, with no infections or flap loss. Six months postoperatively, CT showed that the iliac crest bone had connected to the alveolar bone of the mandible. The height of the iliac crest bone was sufficient for postoperative dental restoration. The patient healed without obvious complications and no tumor recurrence.

LESSONS

Chimeric DCIAPF is an excellent option for mandibular angle or body segment defects combined with significant soft tissue defects.

Postoperative morphological changes over time of vascularized scapular bone used for mandibular reconstruction: A retrospective cohort study

BACKGROUND

Currently, sequential morphological changes of vascularized scapular bone for mandibular reconstruction have remained unreported.

METHODS

We retrospectively analyzed 18 patients with defects on the lateral segment of the mandible who underwent postoperative computed tomography (CT) scanning at 1, 6, 12, and 24 months postoperatively. Using the cross-sectional coronal CT images during each assessment, we measured the height and thickness of the grafted scapular bone at points 10 and 30 mm away from the mesial segment and evaluated their differences over time. Then, the relationship between the morphological changes of the grafted scapular bone and the distance from the mesial bone segment, the number of occlusal supports on the contralateral side of the mandible, and the correlation of sex and age were evaluated.

RESULTS

The height of the grafted scapular bone decreased by approximately 11% and its thickness increased by 14% within 24 months postoperatively. The bone thickness increase was greater at point 30 mm from the mesial bone segment. Patients with two occlusal contacts (premolar and molar) on the contralateral side had a significantly higher rate of bone thickness increase. Furthermore, the graft morphology was not associated with age or sex.

CONCLUSION

A vascularized scapular bone thickens over time, which depends on the distance from the mesial bone segment and the occlusal contact regions on the contralateral side of the mandible.

Patient-Specific Mandibular Reconstruction Plates Increase Accuracy and Long-Term Stability in Immediate Alloplastic Reconstruction of Segmental Mandibular Defects

OBJECTIVES

The aim of the current study was to evaluate potential differences in the accuracy of mandibular reconstruction and long-term stability, with respect to different reconstructive procedures.

METHODS

In total, 42 patients who had undergone primary segmental mandibular resection with immediate alloplastic reconstruction, with either manually pre-bent or patient-specific mandibular reconstruction plates (PSMRP), were included in this study. Mandibular dimensions, in terms of six clinically relevant distances (capitulum [most lateral points], capitulum [most medial points], incisura [most caudal points], mandibular foramina, coronoid process [most cranial points], dorsal tip of the mandible closest to the gonion point) determined from tomographic images, were compared prior to, and after surgery.

RESULTS

Dimensional alterations were significantly more often found when conventionally bent titanium reconstruction plates were used. These occurred in the area of the coronoid process (p = 0.014). Plate fractures were significantly (p = 0.022) more often found within the manually pre-bent group than within the PSMRP group (17%/0%).

CONCLUSION

The results suggest that the use of PSMRP may prevent rotation of the proximal mandibular segment, thus avoiding functional impairment. In addition, the use of PSMRP may potentially enhance the long-term stability of alloplastic reconstructions.

Reconstruction of Oromandibular Defect After Tumor Resection by Sternomastoid-clavicular Flap

ABSTRACT

The study aims to evaluate sternocleidomastoid-clavicular osteo-myocutaneous flap (SCM-OMCF) for reconstruction of mandibular defects after tumor resection. In the period between 2010 and 2018, thirteen patients with primary mandibular tumors underwent mandibular resection and reconstruction with SCM-OMCF. Patients were followed up for 10 to 66 months. Hospital was 13 ± 4 days. All patients started fluid in the 2nd day. The mean time to start oral fluid was 7.5 ± 0.8 day. Four (30.8%) patients suffered from complications (infection and salivary leak in 1 case due to partial flap loss, donor wound dehiscence in 1 case, deep venous thrombosis in 1 case and chest infection in 1 case). None of our cases experienced motor disability. Two cases (15.9%) underwent reoperations. The overall aesthetic outcome was found excellent in 5 cases, satisfactory in 5 cases and fair in 3 cases. The functional outcomes were satisfactory. Tumor recurrences were detected in 2 (15.9%) patients. Two patients died during follow up within 2 years after 1st surgery due to local and distant recurrences. SCM-OMCF is a versatile, safe and simple technique for reconstructing mandibular defects less than 11 cm.

Teriparatide (recombinant parathyroid hormone 1-34) enhances bone allograft integration in a clinically relevant pig model of segmental mandibulectomy

Massive craniofacial bone loss poses a clinical challenge to maxillofacial surgeons. Structural bone allografts are readily available at tissue banks but are rarely used due to a high failure rate. Previous studies showed that intermittent administration of recombinant parathyroid hormone (rPTH) enhanced integration of allografts in a murine model of calvarial bone defect. To evaluate its translational potential, the hypothesis that rPTH would enhance healing of a mandibular allograft in a clinically relevant large animal model of mandibulectomy was tested. Porcine bone allografts were implanted into a 5-cm-long continuous mandible bone defect in six adult Yucatan minipigs, which were randomized to daily intramuscular injections of rPTH (1.75 μg/kg) and placebo (n = 3). Blood tests were performed on Day 56 preoperation, Day 0 and on Day 56 postoperation. Eight weeks after the surgery, bone healing was analyzed using high-resolution X-ray imaging (Faxitron and micro computed tomography [CT]) and three-point bending biomechanical testing. The results showed a significant 2.6-fold rPTH-induced increase in bone formation (p = 0.02). Biomechanically, the yield failure properties of the healed mandibles were significantly higher in the rPTH group (yield load: p < 0.05; energy to yield: p < 0.01), and the post-yield displacement and energy were higher in the placebo group (p < 0.05), suggesting increased mineralized integration of the allograft in the rPTH group. In contrast to similar rPTH therapy studies in dogs, no signs of hypercalcemia, hyperphosphatemia, or inflammation were detected. Taken together, we provide initial evidence that rPTH treatment enhances mandibular allograft healing in a clinically relevant large animal model.

LepR-Expressing Stem Cells Are Essential for Alveolar Bone Regeneration

Stem cells play a critical role in bone regeneration. Multiple populations of skeletal stem cells have been identified in long bone, while their identity and functions in alveolar bone remain unclear. Here, we identified a quiescent leptin receptor–expressing (LepR+) cell population that contributed to intramembranous bone formation. Interestingly, these LepR+ cells became activated in response to tooth extraction and generated the majority of the newly formed bone in extraction sockets. In addition, genetic ablation of LepR+ cells attenuated extraction socket healing. The parabiosis experiments revealed that the LepR+ cells in the healing sockets were derived from resident tissue rather than peripheral blood circulation. Further studies on the mechanism suggested that these LepR+ cells were responsive to parathyroid hormone/parathyroid hormone 1 receptor (PTH/PTH1R) signaling. Collectively, we demonstrate that LepR+ cells, a postnatal skeletal stem cell population, are essential for alveolar bone regeneration of extraction sockets.

The use of muscle extracellular matrix (MEM) and SCPC bioceramic for bone augmentation

BACKGROUND

Bone augmentation is a challenging problem in the field of maxillofacial surgery.

OBJECTIVE

In this study, we prepared and evaluated muscle extracellular matrix (MEM) after adding silica calcium phosphate composite (SCPC) seeded with human bone marrow mesenchymal cells (hBMSCs). We then investigated bone augmentation in vivo using the prepared MEM-SCPC.

MATERIALS AND METHODS

hBMSCs were seeded on MEM-SCPC, and MEM was characterized. Calvarial bone grafts were prepared using nude mice (n = 12) and grafted separately in two experimental groups: grafts with MEM (control, n = 4) and grafts with MEM-SCPC-hBMSCs (experimental group, n = 8) for 8 weeks. Micro-computed tomography (micro-CT) and histological analysis were then performed.

RESULTS

Micro-CT analysis demonstrated a thinner trabeculae in grafted defects than normal native bone, with a high degree of anisotropy. Quantitative histomorphometric assessment showed a higher median bone percentage surface area of 80.2% ± 6.0% in the experimental group.

CONCLUSION

The enhanced bone formation and maturation of bone grafted with MEM-SCPC-hBMSCs suggested the potential use of this material for bone augmentation.

Reconstructing the Face of War

Introduction

Ongoing combat operations in Iraq, Afghanistan, and other theaters have led to an increase in high energy craniomaxillofacial (CMF) wounds. These challenging injuries are typically associated with complex tissue deficiencies, evolving areas of necrosis, and bony comminution with bone and ballistic fragment sequestrum. Restoring form and function in these combat-sustained CMF injuries is challenging, and frequently requires local and distant tissue transfers. War injuries are different than the isolated trauma seen in the civilian sector. Donor sites are limited on patients with blast injuries and they may have preferences or functional reasons for the decisions to choose flaps from the available donor sites.

Methods

A case series of patients who sustained severe combat-related CMF injury and were treated at Walter Reed National Military Medical Center (WRNMMC) is presented. Our study was exempt from Institutional Review Board review, and appropriate written consent was obtained from all patients included in the study for the use of representative clinical images.

Results

Four patients treated by the CMF team at Walter Reed National Military Medical Center are presented. In this study, we highlight their surgical management by the CMF team at WRNMMC, detail their postoperative course, and illustrate the outcomes achieved using representative patient clinical images. We also supplement this case series demonstrating military approaches to complex CMF injuries with CMF reconstructive algorithms utilized by the senior author (EDR) in the management of civilian complex avulsive injuries of the upper, mid, and lower face are thoroughly reviewed.

Conclusion

While the epidemiology and characteristics of military CMF injuries have been well described, their management remains poorly defined and creates an opportunity for reconstructive principles proven in the civilian sector to be applied in the care of severely wounded service members. The War on Terror marks the first time that microsurgery has been used extensively to reconstruct combat sustained wounds of the CMF region. Our manuscript reviews various options to reconstruct these devastating CMF injuries and emphasizes the need for steady communication between the civilian and military surgical communities to establish the best care for these complex patients.

Spontaneous Osteogenesis of a Traumatic Mandibular Defect in the Pediatric Population

Spontaneous osteogenesis of traumatic mandibular defects in the pediatric population remains a relatively rare phenomenon with only 2 patients reported in the literature. In the adult population, a low threshold exists for bone graft placement in the presence of small mandibular gaps, with no role for spontaneous osteogenesis in significant mandibular defects. The approach to traumatic mandibular defects in the pediatric population is not clearly described in the literature and the risks and benefits associated with donor site morbidity of bone graft harvest must be tempered by the possibility for potential spontaneous osteogenesis. The present study reports 1 such patient in whom a significant mandibular defect healed by means of rigid fixation of the defect and spontaneous osteogenesis, with no functional or esthetic sequelae at long-term follow-up. A review of the pertinent literature was performed, and the authors' approach is discussed. The authors propose that traumatic mandibular defects of < 3 cm in patients under the age of 10 years should be considered for treatment with rigid internal fixation alone and spontaneous osteogenesis.

Biomaterials-aided mandibular reconstruction using in vivo bioreactors

Large mandibular defects are clinically challenging to reconstruct due to the complex anatomy of the jaw and the limited availability of appropriate tissue for repair. We envision leveraging current advances in fabrication and biomaterials to create implantable devices that generate bone within the patients themselves suitable for their own specific anatomical pathology. The in vivo bioreactor strategy facilitates the generation of large autologous vascularized bony tissue of customized geometry without the addition of exogenous growth factors or cells. To translate this technology, we investigated its success in reconstructing a mandibular defect of physiologically relevant size in sheep. We fabricated and implanted 3D-printed in vivo bioreactors against rib periosteum and utilized biomaterial-based space maintenance to preserve the native anatomical mandibular structure in the defect site before reconstruction. Nine weeks after bioreactor implantation, the ovine mandibles were repaired with the autologous bony tissue generated from the in vivo bioreactors. We evaluated tissues generated in bioreactors by radiographic, histological, mechanical, and biomolecular assays and repaired mandibles by radiographic and histological assays. Biomaterial-aided mandibular reconstruction was successful in a large superior marginal defect in five of six (83%) sheep. Given that these studies utilized clinically available biomaterials, such as bone cement and ceramic particles, this strategy is designed for rapid human translation to improve outcomes in patients with large mandibular defects.

A systematic review of validated tools assessing functional and aesthetic outcomes following fibula free flap reconstruction of the mandible

BACKGROUND

Segmental mandibulectomy impairs health-related quality of life (QoL), by altering speech, mastication, swallowing, and facial aesthetics. Fibula free flap (FFF) used for mandible reconstruction is known to improve outcomes; however, minimal information exists in the literature regarding patient-reported outcomes. We aim to assess how current studies evaluate patient perception following segmental mandibulectomy and FFF mandible reconstruction.

METHODS

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a search was conducted for publications involving FFF mandible reconstruction from 2005 to 2017 using PubMed, Cochrane, EMBASE, Web of Science, and PsychInfo.

RESULTS

Of 2212 articles identified initially, only 7 studies were deemed suitable. Six studies used the University of Washington Quality of Life questionnaire, 3 Oral Health Impact Profile, and 1 used European Organization for Research and Treatment of Cancer Head and Neck (EORTC-H&N35).

CONCLUSIONS

There is a paucity of information in published reports on QoL outcomes following mandible reconstruction with FFF. In the era of patient-centered health care, observations warrant attention from researchers for physician-assessed patient-reported measures to factor in QoL expectation during surgical decision-making about the choice of reconstruction.

Prosthetic Rehabilitation of Hemimandibulectomy Defect with Removable Partial Denture Prosthesis Using an Attachment-Retained Guiding Flange

The restoration of normal function and esthetics is often challenging in the prosthetic rehabilitation of patients with hemimandibulectomy defects due to unstable occlusion and mandibular deviation. The extensive period of time for completion of healing of the reconstructed mandible through reconstructive plastic surgery and/or implant-assisted prosthesis may compromise the masticatory function by causing delay in the fabrication of definitive prosthesis. This case report describes a novel technique for the construction of customized attachment-retained mandibular guiding flange prosthesis for immediate rectification of the frontal plane rotation occurring after hemimandibulectomy.

Fibular osteofasciocutaneous flap in computer-assisted mandibular reconstruction: technical aspects in oral malignancies

Virtual surgical planning technology in head and neck surgery is witnessing strong growth. In the literature, the validity of the method from the point of view of accuracy and clinical utility has been widely documented, especially for bone modelling. To date, however, with its increased use in head and neck oncology, and consequently the increased need for bone and soft tissue reconstruction, is important to carry out the virtual programme considering not only bone reconstruction but also all aspects related to the reconstruction of soft tissue using composite flaps. We describe our approach to virtual planning in the case of composite flaps. The study reports six consecutive patients with malignant disease requiring mandibular bone and soft tissue reconstruction using fibular osteocutaneous flaps. In all six patients, the resection and reconstruction were planned virtually focusing on the position of cutaneous perforator vessels in order to schedule fibula cutting guides. There were no complications in all six cases. The technique described allowed us to schedule composite fibula flaps in mandibular reconstruction virtually with good accuracy of the position of the bone segment in relation to the cutaneous paddle, important for soft tissue reconstruction. Despite the limited number of cases, the preliminary results of the study suggest that this protocol is useful in virtual programmes using composite flaps in mandibular reconstruction. Further investigations are needed.

The Strategy of Delayed Reconstruction of the Mandible in War Injuries

The most common causes of mandibular defects are ablative surgery of benign or malignant tumors, severe trauma, inflammatory diseases, and osteoradionecrosis. War injuries are another cause for mandibular defect. Reconstruction of the mandible is considered a challenge to the maxillofacial surgeon due to the accompanying functional and cosmetic importance. The object of this article was to show the role of nonvascularized bone graft in the reconstruction of segmental defect of the mandible resulted from projectiles and its snags. Seventeen patients underwent reconstruction of defect in the body of the mandible using non-vascularized iliac bone graft,in sixteen patients the grafts were fixed by reconstruction plate and in one by stainless-steel wire. In the emergency phase in which life-saving measures were done, in the immediate phase, treatments of associated facial and systemic injuries were carried out. The delayed phase includes the reconstruction of the residual defects and rehabilitation. A total of 17 male patients with a mean age of 34.5 years underwent reconstructive surgery, the time lapse between the injury and the delayed phase of treatment ranged from 20 days to 3 months. The size of the defects ranged from 4 to 7 cm. Treatment was considered successful in 15 patients (88.2%) in whom the grafts were incorporated to mandible with improvement of facial contour and symmetry and satisfactory occlusion of the remaining teeth. Nonvascularized bone graft is considered a feasible option for the reconstruction of a relatively small mandibular defect, especially in ascetic conditions for its role in improving facial appearance and to less extent functional benefit and more advanced method for the reconstruction needed to be introduced especially in war injuries.

Patient's Self-Assessment of Social-Approval After Mandibulectomy with Disarticulation: the Necessity for Jaw Reconstruction Following Loss of Facial Symmetry in a Resource-Poor African Setting

OBJECTIVE

Mandibulectomy with disarticulation is usually carried out without reconstruction in Low-Income-Countries. Lower standards of living are usually acceptable and adapted to, in poor societies. This study compares patient's self-assessment of social approval among reconstructed and non-reconstructed cases of mandibulectomy with disarticulation in a resource-poor African setting.

MATERIAL AND METHOD

This questionnaire-based study documented patient's self-assessment of social approval of themselves following mandibulectomy with disarticulation. 12 derived queries were administered on each patient, to test what they perceived of social acceptability of their facial features following mandibulectomy.

RESULTS

All 10 patients who underwent mandibular reconstruction reported that they felt confident engaging in all forms of social activity, while all 10 who had resection without reconstruction did not.

CONCLUSION

The low social approval perceived by patients who have undergone mandibulectomy with disarticulation without reconstruction necessitates that surgeons must strive to reconstruct this anatomical region even under circumstances of severe resource-constraint. The culture in the third-world is not supportive of patients who have not undergone reconstruction following resection, in spite of being victims of all-pervading poverty.

LEVEL OF EVIDENCE

Level IV, investigative study.

A new concept for implant-borne dental rehabilitation; how to overcome the biological weak-spot of conventional dental implants?

Background

Every endosseous dental implant is dependent on an adequate amount and quality of peri-implant hard and soft tissues and their fully functional interaction. The dental implant could fail in cases of insufficient bone and soft tissues or due to a violation of the soft to hard tissues to implant shoulder interface with arising of a secondary bone loss.

Method

To overcome this biological weak-spot, we designed a new implant that allows for multi vector endosseous anchorage around the individual underlying bone, which has to be scanned by computed tomography (CT) or Cone beam CT (CBCT) technique to allow for planning the implant. We developed a workflow to digitally engineer this customized implant made up of two planning steps. First, the implant posts are designed by prosthodontic-driven backward planning, and a wireframe-style framework is designed on the individual bony surface of the recipient site. Next, the two pieces are digitally fused and manufactured as a single piece implant using the SLM technique (selective laser melting) and titanium-alloy-powder.

Results

Preoperative FEM-stress-test of the individual implant is possible before it is inserted sterile in an out-patient procedure.

Conclusion

Unlike any other historical or current dental implant protocol, our newly developed “individual patient solutions dental” follows the principle of a fully functional and rigid osteosynthesis technology and offers a quick solution for an implant-borne dental rehabilitation in difficult conditions of soft and hard tissues.

Ameloblastoma resection with immediate rib reconstruction: addressing the problem of mandibular angle and central bone bulk

Several methods are available to treat mandibular tumours. This case series demonstrates the feasibility of resection and immediate reconstruction with free rib graft in limited resource settings. Innovative technical modifications are described to handle the problem of reconstruction of the angle of the mandible and to provide increased bone bulk in the centre of the mandible. Early postoperative complications are few. Follow-up demonstrates good functional results.

Implant rehabilitation in fibula-free flap reconstruction: A retrospective study of cases at 1-18 years following surgery

PURPOSE

To determine the dental implant and prostheses success rate in a cohort of patients who underwent a vascularized fibula-free flap (FFF) for maxillary or mandibular reconstruction.

METHODS

The investigators implemented a retrospective cohort study composed of patients who had undergone primary or secondary FFF reconstruction jaw surgery plus placement of 2-6 implants in the reconstructed arch, which were restored with an implant-supported prosthesis. The sample was composed of all patients who underwent FFF surgery between 1998 and 2012 and had either simultaneous or secondary dental implant placement. A total of 28 patients met inclusion criteria. Of these, 22 patients participated in the retrospective review. Patients were examined by an independent observer between January-December 2015. In addition, all patients completed a questionnaire to access satisfaction with the implant-supported prosthesis.

RESULTS

The patient cohort consisted of 12 males and 10 females, age 12-70 years. A total of 100 implants were placed, 92 implants in fibular bone and 8 implants in native bone. In the maxilla, 35 implants were placed into fibular bone and 4 into native bone (11 in irradiated patients and 28 in non-irradiated patients). In the mandible, 57 implants were placed into fibular bone and 4 into native bone (15 in irradiated patients and 46 in non-irradiated patients). The mean follow-up after implant loading was 7.8 years (range 1.3-17.5 years). The implant survival rate was 98% (95% CI: 92.2%-99.5%). No statistically significant difference was found in implant success between maxillary and mandibular implants, or between radiated and non-radiated bone. The prostheses success rate, determined by clinical exam and patient satisfaction, was 100%.

CONCLUSION

The results of this study suggest that implant survival is high and implant-supported prostheses are a reliable rehabilitation option in patients whose jaws have been reconstruction with a FFF.

Evaluation of bone resorption in fibula and deep circumflex iliac artery flaps following dental implantation: A three-year follow-up study

Long-term results of dental implant treatment in fibula free and deep circumflex iliac artery (DCIA) free flaps are scarce. The purpose of this study was to assess and compare peri-implant bone resorption of vascularized bone flaps treated with dental implants. A total of 28 patients, 14 fibula and 14 DCIA flaps, respectively, underwent reconstruction of the lower and upper jaw by the use of vascularized bone flaps and were treated with dental implants. Peri-implant bone resorption was measured using digital panographs up to 3 years. Radiographic pictures were taken immediately after implant surgery before prosthetic rehabilitation (T0), the second after 6-12 months (T1), the third after 13-24 months (T2), and the fourth after 25-36 months (T3). Over a period of 3 years, implant resorption changed significantly over time (p_D1 = 0.0113, p_D2 = 0.0232, p_D3 = 0.0143). However, a significant difference in overall resorption between implants with fibula flaps and DCIA could not be detected for the patient average or within the implant-level analysis. Flaps presented minimal resorption from beneath (mean resorption DCIA 0.65, fibula = 0.26). Strong peri-implant bone resorption changed significantly over time. However, no significant difference was observed between fibula and DCIA flaps.

Bone Allograft: An Option for Total Mandibular Reconstruction

Total mandibular reconstruction is one of the most challenging modalities in maxillofacial surgery. In this article, we try to introduce a method of total mandible reconstruction. We report a 25-year-old male patient with complete involvement of the mandible by Langerhans cell tumor. The patient underwent total mandibulectomy and reconstruction with bone allograft harvested from a donor who had died the day before. The patient has good functional and aesthetic results in a long time. It seems that bone allograft can be a good alternative to other methods in total mandibular reconstruction.

Clinical safety and efficacy of implantation of octacalcium phosphate collagen composites in tooth extraction sockets and cyst holes

It was demonstrated that octacalcium phosphate collagen composite achieved notable bone regeneration in bone defects in preclinical studies. On the basis of the research results, an investigator-initiated exploratory clinical trial was conducted after approval from a local Institutional Review Board. This clinical study was performed as a single-arm non-randomized intervention study. Octacalcium phosphate collagen composite was implanted into a total of 10 cases of alveolar bone defects after tooth extractions and cystectomy. Safety assessment was performed in terms of the clinical course and several consecutive laboratory examinations, and sequential radiographs were used for efficacy assessment. All participants uneventfully completed the clinical trial without major problems in their general condition. Postoperative wound swelling was observed, as also commonly seen in tooth extraction or cystectomy. Although no serious liver dysfunction, renal dysfunction, electrolyte imbalance, or abnormal urinalysis results were recognized, the number of white blood cells and C-reactive protein level temporarily increased after the operation. An increase in radiopacity in the octacalcium phosphate collagen composite–implanted site was observed in all cases. Finally, the border between the original bone and the octacalcium phosphate collagen composite–implanted site became indistinguishable. These results suggest that octacalcium phosphate collagen composite could be utilized safely in clinical situations in the future.