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Use of a three-dimensional custom-made porous titanium prosthesis for mandibular body reconstruction with prosthetic dental rehabilitation and lipofilling
Abstract
Reconstruction of mandibular substance loss by a free flap is a widely used technique. This technique suffers from several disadvantages, including the presence of a second intervention site and a substantial frequency of complications. We have undertaken a custom-made 3-dimensional reconstruction (using computer-aided design and manufacturing) with prosthetic dental rehabilitation and esthetic improvement by lipomodeling of the face. A 50-year-old woman presented with a massive recurrence of an ameloblastoma of the right hemimandible. A cervical approach was used to resect the mandible well away from the tumor site. In light of her refusal to undergo reconstruction by a fibula free flap, reconstruction was performed using a custom-made porous titanium device with dental prosthetic rehabilitation, followed by lipomodeling of the face. The reconstruction was achieved without the occurrence of any complications. The implant-supported prosthetic dental implantation and the lipofilling resulted in functionally and esthetically satisfactory outcomes. Three-dimensional mandibular reconstruction with a custom-made porous titanium device and lipofilling yielded satisfactory results. Fitting of the dental prosthesis was undertaken at an early stage as it did not require osseointegration, although there was a need to overcome difficulties linked with the seal and the stability of the dental prosthesis and titanium support. The duration of patient follow-up was 18 months.
... The recommended technique for mandibular reconstruction is the pedicled flap plus a titanium megaplate [2]. Although this method offers the filling tissue required and specific support, distinct limitations have been described: the establishment of a new surgical place, megaplate exposure or fractures, complications with the articulation, and several esthetic consequences [3][4][5]. Recently, three-dimensional (3D) custom-made porous titanium plates have been used for mandibular reconstructions, which offer an alternative in those cases of free flap contraindications or refusal by the patient; however, only very short-term follow-ups have been reported. This case report presents a mandibular reconstruction including a custom-made porous titanium plate with a hybrid dental prosthesis followed for 4 years. ...
... Those patients had a history of ameloblastoma and squamous cell carcinoma. Touré and Gouet [5] treated a patient with a massive recurrence of ameloblastoma of the right hemimandible. The period of patient's follow-up was up to 18 months and was treated with an implant-supported prosthesis. ...
... The present case, together with the cases previously described by Qassemyar et al. [3] and Touré and Gouet [5], has used dental implants. The different advantages presented by this kind of 3D custom-made porous titanium plates for complete reconstructions together with dental implants are relevant [3,5,13,14]. ...
A clinical case of a 42-year-old woman patient, who had a mandibular reconstruction utilizing a three-dimensional (3D) custom-made porous titanium plate dental restoration, is presented. She showed a recurrence of a unicystic ameloblastoma involving the left hemimandible. The patient declined to be managed by a bone-free flap. A mandibular resection in the healthy areas was provided, followed by reconstruction utilizing a 3D custom-made porous titanium plate dental restoration with a hybrid dental prosthesis. The 3D rehabilitation was created considering slim tomodensitometric sections. The cutting guides and custom-created 3D plate were fabricated employing medical software via computer-aided design and fabricating with locations planned for healing abutments. The patient was contented with the rehabilitation, and the condition continued stable at the four-year follow-up.
... However, the use of porous structures alone may not fully restore biting function. Therefore, many researchers have attempted to integrate abutment structures into mandibular implants 15,16 , with several successful cases reported in the literature [17][18][19] . ...
For patients with mandibular bone defects, although reconstruction plates can be used for repair, achieving both occlusal function and facial aesthetics is challenging. In the present study, in vitro experiments and finite element analysis (FEA) were conducted to determine the biomechanical characteristics of multiple porous lattice structures of varying shapes and diameters that were used for mandibular implants. Additionally, an abutment designed to carry occlusal forces was added to the tops of the implants. The stress distribution of four lattice designs (Tetrahedron, Quad-diametral-cross, Hex-star, and Hex-vase) of three sizes (2.5, 3.0, and 3.5 mm) in cubic porous models were analysed by FEA. Subsequently, two optimal designs for 3D-printed titanium alloy were selected. These designs, featuring different lattice diameters (0.5, 0.7, and 0.9 mm), were tested to determine their elastic modulus. These elastic modulus were used in another FEA of a mandibular implant designed for a patient with a malignant tumor in the right mandible. This model, which included an abutment design, was subjected to a vertical force of 100 N and muscle forces generated by biting. This analysis was conducted to determine the elastic modulus of the implant and the values of stress and strain on the implant and surrounding bone. The lattice designs of Quad-diametral-cross and Hex-vase exhibited smaller high-stress regions than those of Tetrahedron and Hex-star did. In vitro tests revealed that the elastic modulus of the lattices increased with the rod diameter. When these values were applied in mandibular implants, Young’s modulus decreased, which in turn increased the frictional stress observed at the interface between the abutment and the implant. However, the implant’s maximum stress remained below its yield strength (910 MPa), and the strain on the surrounding bone varied between 1500 and 3000 µstrain. As indicated by Frost’s theory, these implants are unlikely to damage the surrounding bone tissue and are likely to support bone growth. In conclusion, the lattice designs of Quad-diametral-cross and Hex-vase have small high-stress regions for mandibular implants. Increasing the diameter of the lattice rods increases Young’s modulus, which in turn reduces the frictional stress between the abutment and the implant. Even when the highest Young’s modulus is reached, the stress on the implant remains below its yield strength, and the bone strain remains within the range of 1500 to 3000 µstrain.
... Several advantages of this approach include the exit of the fibular flap from the long vascular pedicle, segmented blood supply, availability as a composite tissue, and enough bone volume for host dental implants. [5][6][7] However, reconstruction procedures remain challenging for surgeons because bone plate fatigue fractures may occur due to pre-bent implants to conform to the mandibular curvature. [8][9][10] Furthermore, these implants may not precisely match the patient's mandibular curvature, resulting in the inability to fully restore patient appearance and bite functionality. ...
Three-dimensional (3D) printing technology used to manufacture patient-specific, large-scale medical implants has become increasingly prevalent. Nevertheless, early biomechanics monitoring can enhance the implantation success rate. This study developed a wireless module system (WMS) for strain gauge measurement that can be placed within the implant to achieve early biomechanical behavior detection for an experimental 3D-printed metal model of a patient-specific segmental implant (MMPSI) after surgery. This WMS includes a chip, a circuit board, and a battery, all with dimensions smaller than 20 mm × 12 mm × 8 mm. This system can connect to strain gauges and interface with a mobile application for measuring and transmitting strain data. The WMS functionality was confirmed through cantilever beam experiments. Premature failure was detected using this WMS installed in an experimental 3D-printed MMPSI and through in vitro fatigue biomechanical testing under different occlusal forces applied on the plastic-simulated mandibular model. The WMS validation results indicated that the strain gauge measurement error compared to theoretical values was within 17%. Biomechanical fatigue results addressed the higher strain received and greater cyclic loads were recorded when occlusal force was applied onto the premolar under identical force application conditions because the premolar was closer to the strain gauge attachment location, resulting in a longer lever arm compared to the molar. This study concluded that the developed WMS for strain measurement can be installed in a patient-specific 3D-printed implant with enough internal space to detect early biomechanical behavior after surgery. Current results of in vitro fatigue test for segmental defect indicated that occlusal situation can be adjusted to reduce implantation failure risk.
... Some sporadic case reports focus on the use of 3D printed mandibles with incorporated dental implants. 4,9,10,39,40 In these cases, the abutment was directly fused with the CMP. However, the concept of designing the iPRD based on masticatory stress dispersion efficiency remains unexplored. ...
Background/purpose
Segmental body defects of the mandible result in the complete loss of the affected region. In our previous study, we investigated the clinical applicability of a customized mandible prosthesis (CMP) with a pressure-reducing device (PRD) in an animal study. In this study, we further incorporated dental implants into the CMP and explored the use of dental implant PRD (iPRD) designs.
Materials and methods
By employing a finite element analysis approach, we created 4 types of CMP: CMP, CMP with iPRD, CMP-PRD, and CMP-PRD with iPRD. We developed 2 parameters for the iPRD: cone length (CL) in the upper part and spring pitch (SP) in the lower part. Using the response surface methodology (RSM), we determined the most suitable structural assignment for the iPRD.
Results
Our results indicate that CMP-PRD had the highest von Mises stress value for the entire assembly (1076.26 MPa). For retentive screws and abutments, CMP with iPRD had the highest von Mises stress value (319.97 and 452.78 MPa, respectively). CMP-PRD had the highest principal stress (131.66 MPa) in the anterior mandible. The iPRD reduced principal stress in both the anterior and posterior mandible. Using the RSM, we generated 25 groups for comparison to achieve the most favorable results for the iPRD and we might suggest the CL to 12 mm and the SP to 0.4 mm in the further clinical trials.
Conclusion
Use of the PRD and iPRD in CMP may resolve the challenges associated with CMP, thereby promoting its usage in clinical practice.
... In case of failure, a new prosthesis or microsurgical flap or a combination of a new prosthesis with bone reconstruction by microsurgical flaps or bone chips can be considered [34][35][36][37]. ...
Virtual surgical planning for CAD/CAM mandibular reconstruction by titanium prosthesis was recently reported for resected cases. Even if some advantages are evident, difficulties that may arise for TMJ function after reconstruction originate from prosthesis contamination through oral mucosa dehiscence. In these two cases reported of mandibular reconstruction after resection of ameloblastoma by custom-made CAD/CAM titanium prosthesis, the procedures were aimed to preserve the TMJ glenoid cavity and articular disc avoiding functional problems for hemi-mandibular resections that included the condyle (as in case #1) or with condylar preservation (as in case #2) and avoiding intraoral incisions in both cases. The entire surgical planning and prosthetic fabrication were explained with specifications and the sequence of the surgical procedure. Finite elements analysis (FEA) was performed to check the force distribution and efficacy of the prosthetic device (case 1 with hemi-mandibular resection and rehabilitation). Although successful in these two cases, surgical reconstruction of the mandibular defect after resection by a CAD-CAM custom-made prosthesis still shows some drawbacks and failure risks. Several advantages of this technique and the surgical success in these two cases were presented, but limitations and side effects must be considered when cases are selected.
... Together with the cases previously described by Qassemyar et al. and Touré and Gouet [17], the different advantages presented by this type of 3D custom-made porous titanium plates for complete reconstruction are significant and treatment outcomes can be largely influenced. ...
Ameloblastoma is a benign yet locally invasive odontogenic neoplasm, characterised by slow growth and painless swelling. The treatment for ameloblastoma varies from curettage to en bloc resection, with recurrence commonly occurring. The safety margin of resection is hence essential to avoid recurrence. Understanding the three-dimensional anatomy for reconstruction of mandibular defects after tumour resection often poses problems for head and neck surgeons. Historically, various autografts and alloplastic materials have been used in the reconstruction of these types of defects. Over time, advances in technology with computed tomography scanners and three-dimensional images enhance the surgical planning and management of maxillofacial tumours. The development of new prototyping systems provides accurate 3D biomodels on which surgery can be simulated, especially in cases of ameloblastoma, in which the safety margin is vital for the clinical outcome. The objective of this paper was to report a clinical case of employing these methodologies for reconstruction after an extensive mandibular resection. The clinical outcomes were observed. A case of follicular ameloblastoma of the mandible is depicted in the following paper, where a 3D biomodel was used throughout the surgery. A 3D printed patient-specific titanium implant was manufactured and placed intraoperatively for reconstruction. The treatment had satisfactory postoperative results without complications. Titanium implants being bioinert, customisable and easily workable, especially with the help of 3D virtual planning techniques, can be considered as ideal alloplastic materials for mandibular reconstruction.
... Hong et al. [21] studied rabbits with total customized mandible implant that showed higher and faster recovery rates of their daily food intake amount and higher screws intact rate than those treated with fivehole miniplates without bone grafts. In human studies, several case reports or series used customized mandible implant which behaved as mesh or framework structures with or without artificial bone substitutes [4,22]. Some researchers [1,[23][24][25] further used titanium implant with premounted dental implants for mandible reconstruction. ...
Segmental bony defects of the mandible constitute a complete loss of the regional part of the mandible. Although several types of customized three-dimension-printed mandible prostheses (CMPs) have been developed, this technique has yet to be widely used. We used CMP with a pressure-reducing device (PRD) to investigate its clinical applicability. First, we used the finite element analysis (FEA). We designed four models of CMP (P1 to P4), and the result showed that CMP with posterior PRD deployment (P4 group) had the maximum total deformation in the protrusion and right excursion positions, and in clenching and left excursion positions, posterior screws had the minimum von Mises stress. Second, the P4 CMP-PRD was produced using LaserCUSING from titanium alloy (Ti-6Al-4V). The fracture test result revealed that the maximum static pressure that could be withstood was 189 N, and a fatigue test was conducted for 5,000,000 cycles. Third, animal study was conducted on five male 4-month-old Lanyu pigs. Four animals completed the experiment. Two animals had CMP exposure in the oral cavity, but there was no significant inflammation, and one animal had a rear wing fracture. According to a CT scan, the lingual cortex of the mandible crawled along the CMP surface, and a bony front-to-back connection was noted in one animal. A histological examination indicated that CMP was significantly less reactive than control materials ( p = 0.0170 ). Adequate PRD deployment in CMP may solve a challenge associated with CMP, thus promoting its use in clinical practice.
... The application integrating metal additive manufacturing (AM), medical image processing, and computer-aided design (CAD) technologies to reconstruct patientspecific mandibular continuity defects are accepted to restore the patient appearance and mandible structural strength [1][2][3][4][5][6][7][8][9][10][11] . The subsequent combination of chemical and radiotherapy in clinical practice has greatly improved the mandibular reconstruction surgery success rate [12] . ...
This study developed design criterion for patient-specific reconstructed implants with appearance consideration and structural optimization of various mandibular continuity defects. The different mandible continuity defects include C (from left to right canines), B (from 1st premolar to 3rd molar), and A (from 3rd molar to ramus) segments defined based on the mandible image. The finite element (FE) analysis and weighted topology optimization methods were combined to design internal support beam structures within different reconstructed implants with corresponding occlusal conditions. Five continuity mandibular defects (single B/C/A+B and combination of B+C and B+C+B segments) were restored using additive manufacturing (AM) reconstructed implant and bone plate to confirm reasonable design criterion through biomechanical fatigue testing. The worst mandible strength was filtered based on the material mechanics and results from segmental bone length, thickness, and height statistics from the established database containing mandible images of 105 patients. The weighted optimization analysis results indicated that the sizes and positions of internal supporting beams within the reconstructed C, B, and A+B implants can be defined parametrically through corresponding segmental bone length, width, and height. The FE analysis found that the weight variation percentage between the parametric designed implants and original core solid implants in the C, B, and A+B was reduced by 54.3%, 63.7%, and 69.7%, respectively. The maximum stress values of the reconstructed implant and the remaining bone were not obviously reduced but the stress values were far lower than the material ultimate strength. The biomechanical fatigue testing indicated that all cases using the AM reconstructed implant could pass the 250,000 dynamic load. However, condyle head, bone plate fracture, and bone screw loosening could be found in cases using bone plates. This study developed a design criterion for patient-specific reconstructed implants for various mandibular continuity defects applicable for AM to further clinical use.
... 31,32 A customized prosthetic implant alone has been proposed as a favorable alternative to free flap reconstruction as it decreases morbidity by removing the need to create a second surgical site and subjecting the patient to a lengthy microsurgical procedure. 33 The TMJ Concepts prosthesis, formerly, known as the Techmedica model, was developed in 1989 and consists of mandibular (body and/or ramus) and glenoid fossa components. The mandibular segment is composed of a titanium-aluminum-vanadium shaft and a molybdenum-chromium-cobalt condylar articular head. ...
Ameloblastomas are benign tumors that most commonly affecting the mandible. The current standard of treatment for ameloblastomas is resection followed by reconstruction that has historically been accomplished through the use of a microsurgical vascularized flaps taken from the iliac crest or fibula. Alloplastic reconstruction methods have gained popularity over recent years with success reported in the reconstruction of many pathologies, including ankylosis, condylar fracture, neoplasia involving extensive resection, severe inflammatory/degenerative temporomandibular joint (TMJ) disease, and congenital TMJ abnormalities. The authors present a patient who successfully underwent ameloblastoma resection and TMJ reconstruction with a custom TMJ Concepts alloplastic implant. The authors also present a review of the literature on alloplastic TMJ reconstruction following ameloblastoma resection. To our knowledge, this is the second report in the literature on the use of a TMJ Concepts implant after ameloblastoma resection.
... The fibula free flap is the gold standard surgery for the vascularized graft used to reconstruct severe defects in the mandible because of its versatility, predictability, and favorable fibula bone quantity for dental implants to facilitate prosthetic rehabilitation [1][2][3][4]. The reconstruction plate and fixation screws were used to secure the bone graft in the lower mandible border to bridge the mandibular stumps to bear the occlusal load to maintain fixation stability during the bone healing phase [1,[5][6][7][8]. ...
This study developed a numerical simulation to understand bone mechanical behavior and micro-crack propagation around a fixation screw with severe mandibular defects. A mandible finite element (FE) model was constructed in a rabbit with a right unilateral body defect. The reconstruction implant was designed to be fixed using six screws distributed on the distal and mesial sides. The element death technique provided in FE analysis was combined with bone remodeling theory to simulate bone necrosis around the fixation screw in which the strain value reached the overload threshold. A total of 20 iterations were performed to observe the micro-crack propagation pattern for each screw according to the high strain locations occurring in each result from consecutive iterations. A parallel in vivo animal study was performed to validate the FE simulation by placing specific metal 3D printing reconstruction implants in rabbits to compare the differences in bone remodeling caused by radiation treatment after surgery. The results showed that strain values of the surrounding distal bone fixation screws were much larger than those at the mesial side. With the increase in the number of iteration analyses, the micro-crack prorogation trend for the distal fixation screws can be represented by the number and element death locations during the iteration analysis process. The corresponding micro-movement began to increase gradually and induced screw loosening after iteration calculation. The strained bone results showed that relatively high bone loss (damage) existed around the distal fixation screws under radiation treatment. This study concluded that the FE simulation developed in this study can provide a better predictive diagnosis method for understanding fixation screw loosening and advanced implant development before surgery.
Background
Segmental bone defects of the mandible result in the complete loss of the affected region. We had incorporated the pressure‐reducing device (PRD) designs into the customized mandible prostheses (CMP) and conducted a clinical trial to evaluate this approach.
Methods
Seven patients were enrolled in this study. We examined the association among the history of radiotherapy, the number of CMP regions, the number of chin regions involved, and CMP exposure.
Results
We included five men and two women with an average age of 55 years. We excised tumors with an average weight of 147.8 g and the average weight of the CMP was 68.5 g. No significant difference between the two weights was noted ( p = 0.3882). Three patients received temporary dentures and the CMP remained stable in all patients.
Conclusion
The use of PRD in CMP may address the previous challenges associated with CMP, but further research is necessary.
Background
Ameloblastoma (AM), the benign counterpart of ameloblastic carcinoma, is a benign odontogenic tumor of epithelial origin, naturally aggressive, with unlimited growth potential and a high tendency to relapse if not adequately removed. Patients with AM treated surgically can benefit from dental implant therapy, promoting oral rehabilitation and improving their quality of life. The present study aimed to determine the survival rate of dental implants placed after surgical treatment of patients affected by AM. In addition, there were two secondary objectives: 1) To evaluate which dental implant loading protocols are most frequently used and 2) To determine the type of prosthetic restoration most commonly used in these patients.
Methods
The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines were followed during the study. Searches were performed in three databases (PubMed/MEDLINE, Scopus, and Google Scholar) until November 2023. Additionally, the electronic search was enriched by an iterative hand search of journals related to oral pathology and medicine, maxillofacial surgery, and oral prosthodontics and implantology. Only reports and case series in English from January 2003 to date were included. The Joanna Briggs Institute tool (JBI-Case Reports/Case Series) was used for the study quality assessment.
Results
The total number of patients and implants studied were 64 and 271, respectively, all with surgically treated AM. The patient’s ages ranged from 8 to 79 years, with a mean (SD) age of 37.3 ± 16.4. Fifty-three percent were male and 47% were female. The range of follow-up duration was 1 to 22 years. An implant survival/success rate of 98.1% was reported. In addition, most of them were conventionally loaded (38.3%). Hybrid implant-supported fixed dentures were the most commonly used by prosthodontists (53%).
Conclusions
Oral rehabilitation with dental implants inserted in free flaps for orofacial reconstruction in surgically treated patients with AM can be considered a safe and successful treatment modality.
Purpose:
The Surgical CAse REport (SCARE) guidelines are a standardized format for reporting surgical cases. The aim of this study was to evaluate the completeness of case reports documenting alloplastic reconstruction of large craniomaxillofacial defects involving total mandibular, bilateral, and extended temporomandibular joint in major high-quality craniomaxillofacial journals, based on the SCARE guidelines.
Methods:
An extensive online search was performed according to the Priority Reporting Items for Systematic Reviews and Meta-Analyses statement in PubMed, Embase, Scopus, Google Scholar, and Dimensions databases to identify relevant case reports. Each selected case report was assessed on 16 topics (38 items) of the SCARE guidelines, using a scoring scale of "0" (No/noncompliance), "1" (Yes/compliance), and 2" (unclear). The completeness of reporting (COR) score was calculated as the ratio of "yes" responses to "total" (ie, yes + no + unclear) responses. Adequacy of case reporting was denoted by a COR score of 70% or more.
Results:
A total of 35 case reports were selected, where the male to female patients ratio was 3:4 cases, mean ± standard deviation (SD) age: 34.9 ± 16.7 years, mean ± SD follow-up duration: 17.0 ± 12.9 months, and number of patients with left, right, and bilateral temporomandibular joint reconstruction prostheses were 16, 10, and 09, respectively. The mean ± SD COR score for all 35 case reports and the individual item of the SCARE guidelines was 70.2 ± 10.5% and 66.5 ± 31.2%, respectively. The minimum and maximum COR score was found for "Keywords" (0.0%) and "Introduction" (100%) and "Clinical Findings" (100%), respectively. Adequate reporting was found for 20/35 (57%) case reports.
Conclusions:
This study revealed that case reports in major high-quality craniomaxillofacial journals suffer from insufficient reporting. Widespread adoption of available standards, such as SCARE guidelines, is proposed to improve the quality and robustness of case reporting.
The accurate reconstruction of a defective part of the mandible is a time-consuming task in maxillofacial surgery. In order to design accurate 3D implants quickly, a method for generating a mandibular defect implant model based on deep learning was proposed. First, an algorithm for generating a defective mandible 3D model randomly from a complete mandible 3D model was proposed due to the insufficiency of 3D models. Then a mandible 3D model dataset that consists of defective mandible 3D models and a complete mandible 3D model was constructed. An improved 3D Unet network that combines residual structure and dilated convolution was designed to generate a repaired mandibular model automatically. Finally, a mandibular defect implant model was generated using the reconstruction–subtraction strategy and was validated on the constructed dataset. Compared with the other three networks (3D Unet, 3D RUnet, and 3D DUnet), the proposed method obtained the best results. The Dice, IoU, PPV, and Recall for mandible repair reached 0.9873, 0.9750, 0.9850, and 0.9897, respectively, while those for implants reached 0.8018, 0.6731, 0.7782, and 0.8330. Statistical analysis was carried out on the experimental results. Compared with other methods, the P value of the method proposed in this paper was less than 0.05 for most indicators, which is a significant improvement.
Autologous fat is ideal soft tissue filler. It is easily accessible, biocompatible, cheap, and it provides both volume augmentation and skin quality improvement. Fat grafting has been used since 1893, but it has only gained widespread popularity since the development of modern liposuction by Colemann and Illouz in the 1980s. Every year more than half a million facial fat grafting procedures are carried out worldwide and the trend is rapidly increasing. Overall, general complications associated with facial fat grafting are assumed to be around 2%. Is that true? Material and Methods: Until July 2021, a systematic search of the literature was performed interrogating PubMed search engines. The following algorithm was used for the research: (fat graft OR lipofilling) AND face AND complications. Exclusion criteria applied hierarchically were review articles, not reporting recipient site complications; not in English and paediatric population. Abstracts were manually screened by LS, GS, JM and PDS separately and subsequently matched for accuracy. Pertinent full-text articles were retrieved and analysed and data were extracted from the database. The flow chart of article selection is described following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Results: In total, 462 papers were identified by PubMed search. A total of 359 were excluded: 38 papers were not in English, 41 were review articles, 279 articles did not report recipient site complications and 1 was not on human subjects. Average complication rate ranged from 1.5% to 81.4%. A total of 298 adverse events were identified: 40 (13.4%) intravascular injections, 13 (4.3%) asymmetry, 57 (19.1%) irregularities, 22 (7.4%) graft hypertrophy, 21 (7%) fat necrosis, 73 (24.5%) prolonged oedema, 1 (0.3%) infection, 6 (2%) prolonged erythema, 15 (5%) telangiectasia and 50 (16.8%) cases of acne activation. Conclusions: FFG related side effects could be resumed in three categories: severe, moderate, and minor. Severe (13.4%) side effects such as intravascular injection or migration require neurological or neurosurgical management and often lead to permanent disability or death. Moderate (38.3%) side effects such as fat hypertrophy, necrosis, cyst formation, irregularities and asymmetries require a retouch operation. Minor (48.3%) side effects such as prolonged oedema or erythema require no surgical management. Despite the fact that the overall general complication rate of facial fat grafting is assumed to be around 2%, the real complication rate of facial fat grafting is unknown due to a lack of reporting and the absence of consensus on side effect definition and identification. More RCTs are necessary to further determine the real complication rate of this procedure.
Background
Novel technologies for management and reconstruction of complex bony defects regarding both function and facial appearance are interestingly used in maxillofacial surgery. In the current study, we demonstrated reconstruction of a bilateral ramus-condyle unit (RCU) defect while preserving both condyles by a novel designed titanium prosthesis using virtual surgical planning (VSP), computer-aided design and manufacturing (CAD/CAM), and Selective Laser Melting (SLM) technologies.
Materials and methods
A 3D customized titanium prosthesis was designed for a 49 -year-old patient with bilateral mandibular aggressive central giant cell granuloma (CGCG) according to mandibular normal anatomy and structure while preserving bilateral intact condyles. Finite element study was performed to investigate the effects of new design strength and the stress shielding phenomenon. The design of macro-pores inside the body of prosthesis allowed it to act as a scaffold for bone tissue engineering under load bearing conditions.
Results
Analysis of the strength and stress shielding phenomenon demonstrated favorable outcomes regarding the novel design. For instance, there was no stress shielding in any of the preserved condyles with regard to the size and distribution of stresses. Also, the stress distribution around the pores showed that these pores had no effect on the strength of the prosthesis. Thirty month follow-ups after reconstruction of bilateral RCU defect showed normal jaw function with a favorable facial appearance and mandibular contour.
Conclusion
We design a novel patient-specific prosthesis with desirable biomechanical features for reconstruction of bilateral RCU defect after resection of the benign tumor with preservation of bilateral intact condyles.
The aim of this study was used a weighted topology optimization method to design a patient-specific mandibular implant for reconstruction and restoration of appearance in patients with severe mandibular defects. A finite element (FE) model was constructed and the defect region was defined from the unilateral first premolar to the second molar. The reconstruction implant included main body, fixation wing and dental prosthesis. Standard topology optimization was performed using stress constraint to identify optimal fixation wing structure (denoted as WOS) with solid core main body. Two independent optimal main body with internal beam supporting structures defined as WOSA and WOSO optimized from the WOS model under axial and oblique conditions were then obtained, respectively. Final optimal model (WBOS) was generated using a weighted topology optimization that considered 60% and 40% contributions of WOSA and WOSO models, respectively. The WBOS model was fabricated using metal 3D printing and fixed on the resting acrylonitrile butadiene styrene (ABS) bone to perform fracture testing. Stress concentration were found in the upper area connected to the main body of the mesial wing and corresponding maximum values under axial/oblique loads were reduced from 778/925 MPa of the WOS model to 764/720 MPa of the WBOS model. The reduction in percentage variations of weight between original (91.1 g) and final optimal (24.5 g) models was 73.14% for fabricated 3D printing models. The WBOS model also exhibited a higher resistant force (2163 N) when compared with the original model (1678 N). This study developed a design strategy with weighted topology optimization and fabrication for producing patient-specific implants using metal 3D printing. The obtained reconstruction implant can provide good biomechanical performance and recovery of appearance for oral rehabilitation.
Reconstruction of the lateral mandibular defect presents a complex challenge to the reconstructive surgeon, often involving interconnected soft-tissue and bone requirements. This review examines the current literature on functional outcomes of lateral mandibular reconstruction and presents an algorithm on selecting an optimal reconstructive choice for patients with lateral mandibular defects resulting from oncologic ablative surgery or trauma. PubMed and Medline searches on reconstructing lateral mandibular defect were performed of the English literature. Search terms included lateral mandibular defect, outcomes of mandibular reconstruction, and free flap reconstruction of mandible. Although most of the articles presented are retrospective reviews, priority was given to the articles with high-quality level of evidence. Restoration of function, including speech and swallow, and acceptable cosmetic result are the primary objectives of lateral mandibular reconstruction. When reconstructing the mandible in a patient following tumor extirpation, the patient's overall prognosis, medical comorbidities, and need for adjuvant therapy should be considered. In the patient with aggressive malignant disease and a poor prognosis, a less complex reconstruction, such as soft-tissue flap with or without a reconstruction plate, may be adequate. In a dentate patient with favorable prognosis, a durable reconstruction, such as osseocutaneous microvascular free flap, is often preferred. Various reconstructive options are available for patients with lateral mandibular defects. Depending on the predominance of the soft-tissue or bony components of the defect, with consideration of the patient's characteristics and functional and aesthetic goals, the surgeon can wisely select from these reconstructive possibilities.
The integrity of the peri-implant soft-tissue seal is crucial for maintaining peri-implant tissue health. Whilst the transmucosal component of the restored implant shares some common features with teeth, namely the presence of a junctional epithelium and a connective tissue component, there are some important differences. A key difference is the nature of the relationship of the connective tissue with the implant surface, whereby there is ‘adaptation’ of collagen fibers in a parallel orientation in relation to the implant, but insertion of fiber attachment perpendicularly into cementum in the case of teeth. This, combined with reduced cellularity and vascularity in the peri-implant connective tissue, may make implants more susceptible to disease initiation and progression. Furthermore, the presence of a subgingival connection between the implant and the abutment/restoration poses some specific challenges, and maintaining the integrity of this connection is important in preserving peri-implant tissue health. Implant design features, such as the nature of the connection between the implant and the abutment, as well as the surface characteristics of the abutment and implants, may influence the maintenance of the integrity of soft tissue around implants. Iatrogenic factors, such as incorrect seating of the abutment and/or the restoration, and the presence of residual subgingival cement, will lead to loss of soft-tissue integrity and hence predispose to peri-implant disease.
To understand and reduce the impact of postoperative complications, we studied 568 patients who had had operations over 72 months in our hospital. Multivariate analysis indicated that factors indicative of coexisting conditions (including activated systemic inflammation) and the complexity of the operation are primary determinants of postoperative complications. The enhanced recovery after surgery (ERAS) care pathway did not have an effect on their occurrence or severity. Systematic study of patients' toleration of major head and neck operations is required, as optimal perioperative care pathways remain elusive.
The progress made in recent years in the field of head and neck bone reconstruction is directly related to technological advancements made in computer-aided design and manufacturing (CAD/CAM) and three-dimensional printing in particular. Today these technologies are mainly used in mandibular reconstruction to manufacture aids for harvesting and shaping bone flaps. However problems remain when addressing patients with a contraindication to microsurgery who need extensive bone reconstruction. For these patients who cannot benefit from vascularized bone grafts, surgeons have to find alternative solutions aimed at maintaining best function and aesthetics. The goal of this article is to present an original method for mandibular body replacement with custom-made porous titanium prostheses in patients ineligible for a bone free flap. This solution has been used for two patients with an intraoral approach, resulting in no visible scars, with simple postoperative care of a short duration. This innovative solution represents an additional option for the treatment of complex mandibular reconstructions.
Background:
Free tissue transfer is commonly used in the reconstruction of post-ablative defects of the mandible. Due to lack of statistical power, comparing the survival of various free flaps, even in large studies, is challenging. The purpose of this study was to perform a meta-analysis comparing the survival of the most commonly used free flaps for mandibular reconstruction.
Methods:
We searched PubMed, EMBASE, and SCOPUS for relevant studies. A meta-analysis using the Peto one-step odds ratio (OR) with 95% confidence intervals (CI) was used to compare the pooled survival of the most commonly used free flaps for mandibular reconstruction.
Results:
Of the 25,303 studies reviewed, 17 were selected for data extraction. A total of 1,221 subjects received 1,262 free flaps. Sixty-five free flaps failed. The pooled survival of all free flaps used for mandibular reconstruction was 94.8%. The deep circumflex iliac artery (DCIA) flap was associated with a seven-fold increase in failure when compared to the radial forearm free flap (Peto OR 7.40; 95% CI 1.38, 39.75, P = 0.02). There was no difference in survival when comparing other commonly used free flaps.
Conclusions:
The results of this study suggest that free flap reconstruction of the mandible is highly successful. With the exception of the increased survival of the radial forearm when compared to the DCIA, there is no difference in recipient site survival when comparing various free flaps for mandibular reconstruction. © 2015 Wiley Periodicals, Inc. Microsurgery, 2015.
Microgap between implant and abutment can produce biological and mechanical problems such as peri-implantitis and/or fatigue failures. The aim of this study was to evaluate microgap size and fatigue behavior of external and internal connections. In both systems the torque to tighten the abutment screw of single crown abutments was 45 Ncm. Fifty implants for each connection type were studied. One subgroup (n = 5) was used by the observation and evaluation of the microgap, other (n = 5) was tested for fracture strength and the other (n = 40) was subjected to dynamic loading. The internal connection presents a lower microgap than the external ones. From fatigue results, the external hexagon interface showed superior result compared to the internal hexagon interfaces. The tolerances in the internal connections are better and favour the fatigue behavior but this factor alone is not sufficient to improve the fatigue response in relation to the external connections when the screw is subjected at the same torque. The external system presents a higher value of the area than the internal and it produces a better load distribution. Microgaps and mechanical properties are very important for the long-term behavior of the dental implants and these aspects should be known by the implantologists.
The aim of the present in vitro study was to assess the resistance to static fatigue of implants with different connections at various crown heights.
Sixty conical implants and 60 abutments were used with the smallest diameters available for each model. Three groups (n = 20) were established based on the implant connections: Morse taper Ø3.50 mm (group 1), external hexagon Ø3.50 mm (group 2), and internal hexagon Ø3.50 mm (group 3). Four crown heights were tested: h1 = 8 mm, h2 = 10 mm, h3 = 12 mm, and h4 = 14 mm. All groups were subjected to quasi-static loading at a 30° angle to the implant axis in a universal testing machine.
The mean fracture strengths for group 1 were 1524 N (h1 ), 1469 N (h2 ), 750 N (h3 ), and 729 N (h4 ). Those for group 2 were 1504 N (h1 ), 814 N (h2 ), 491 N (h3 ), and 325 N (h4 ). Those for group 3 were 1543 N (h1 ), 672 N (h2 ), 403 N (h3 ), and 390 N (h4 ).
Resistance to loading decreases significantly with increasing crown height, and the connection design can affect the performance.
Purpose:
The aim of this study was to compare, in vitro, external-hexagon and Morse taper implant systems with respect to bacterial sealing between implants and abutments using a new methodology.
Materials and methods:
Two groups of implants were tested. Group 1 implants had an external-hexagon implant-abutment interface (Neodent) and group 2 implants featured a Morse taper (Neodent) interface. The implants were perforated apically with a 1-mm bur until the bur reached the internal chamber. Prosthetic components were adapted with the recommended torque (32 and 10 Ncm, respectively) for each group. The implants were attached to an assay vial, with the abutment end positioned into the tube. With a sterilized syringe, the assay vials were filled with liquid culture medium (brain heart infusion broth). All the specimens were sterilized by gamma radiation. After the efficacy of sterilization had been confirmed using control samples, the apical hole was carefully opened and inoculated with Escherichia coli.
Results:
Samples were examined daily for evidence of contamination. Within a 14-day period, 60% of the samples of group 1 were contaminated and 30% of group 2 samples were contaminated. After this period there was no further contamination in either group.
Conclusion:
Although both systems exhibited bacterial contamination, the Morse taper implants of the system used in this study provided a better bacterial seal than external-hexagon implants of the same system.
A three dimensional tissue-engineered human oral mucosal model (3D OMM) used in the investigation of implant-soft tissue interface was recently reported. The aim of this study was to examine the ultrastructural features of soft tissue attachment to various titanium (Ti) implant surfaces based on the 3D OMM. Two techniques, that is, focus ion beam (FIB) and electropolishing techniques were used to prepare specimens for transmission electron microscopic (TEM) analysis of the interface. The 3D OM consisting of both epithelial and connective tissue layers was constructed by co-culturing human oral keratinocytes and fibroblasts onto an acellular dermis scaffold. Four types of Ti surface topographies were tested: polished, machined (turned), sandblasted, and TiUnite. The specimens were then processed for TEM examination using FIB (Ti remained) and electropolishing (Ti removed) techniques. The FIB sections showed some artifact and lack of details of ultrastructural features. In contrast, the ultrathin sections prepared from the electropolishing technique showed a residual Ti oxide layer, which preserved the details for intact ultrastructural interface analysis. There was evidence of hemidesmosome-like structures at the interface on the four types of Ti surfaces, which suggests that the tissue-engineered oral mucosa formed epithelial attachments on the Ti surfaces. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2011.
Soft tissue considerations in implant site development. Review
- Geurs