Virtual Surgical Planning, Stereolitographic Models and CAD/CAM Titanium Mesh for Three-Dimensional Reconstruction of Fibula Flap with Iliac Crest Graft and Dental Implants

Long-term survival and success rate of dental implants placed in reconstructed areas with extraoral autogenous bone grafts: A systematic review and meta-analysis

OBJECTIVE

To evaluate the long-term survival and success rates of implants placed in reconstructed areas using microvascularized or non-microvascularized extraoral bone grafts.

MATERIALS AND METHODS

An electronic search was performed in five databases and in gray literature for articles published until June, 2023. The eligibility criteria comprised observational studies (prospective or retrospective) and clinical trials, reporting survival and success rates of implants placed in extraoral bone grafts. A meta-analysis (implant failure) was categorized into subgroups based on the type of bone graft used. The risk of bias within studies was assessed using the Newcastle-Ottawa Scale.

RESULTS

Thirty-one studies met the inclusion criteria. The mean follow-up time was 92 months. The summary estimate of survival rate at the implant level were 94.9% (CI: 90.1%-97.4%) for non-vascularized iliac graft, 96.5% (CI: 91.4%-98.6%) for non-vascularized calvaria graft, and 92.3% (CI: 89.1%-94.6%) for vascularized fibula graft. The mean success rate and marginal bone loss (MBL) were 83.2%; 2.25 mm, 92.2%; 0.93 mm, and 87.6%; 1.49 mm, respectively.

CONCLUSIONS

Implants placed in areas reconstructed using extraoral autogenous bone graft have high long-term survival rates and low long-term MBLs. The data did not demonstrate clinically relevant differences in the survival, success, or MBL of grafts from different donor areas or with different vascularization. This systematic review was registered in INPLASY under number INPLASY202390004.

Application of CAD-CAM Technologies for Maxillofacial Bone Regeneration: A Narrative Review of the Clinical Studies

The application of regenerative methods in treating maxillofacial defects can be categorized as functional bone regeneration in which scaffolds without protection are used and in-situ bone regeneration in which a protected healing space is created to induce bone formation. It has been shown that functional bone regeneration can reduce surgical time and obviate the necessity of autogenous bone grafting. However, studies mainly focused on applying this method to reconstruct minor bone effects, and more investigation concerning the large defects is required. In terms of in situ maxillofacial bone regeneration with the help of CAD-CAM technologies, the present data have suggested feasible mesh rigidity, perseverance of the underlying space, and apt augmentative results with CAD-CAM-based individualized Ti meshes. However, complications, including dehiscence and mesh exposure, coupled with consequent graft loss, infection and impeded regenerative rates have also been reported.

Guided Genioplasty: Comparison between Conventional Technique and Customized Guided Surgery

BACKGROUND

Genioplasty as an isolated surgical technique is a highly demanded procedure in the maxillofacial surgery area. Advances in facial reconstructive surgery have been associated with less morbidity and more predictable results. In this paper, "conventional" genioplasty and genioplasty by means of virtual surgical planning (VSP), CAD-CAM cutting guides, and patient custom-made plates are compared.

METHODS

A descriptive observational study was designed and implemented, and 43 patients were treated, differentiating two groups according to the technique: 18 patients were treated by conventional surgery, and 25 patients were treated through virtual surgical planning (VSP), CAD-CAM cutting guides, STL models, and titanium patient-specific plates.

RESULTS

The operation time ranged from 35 to 107 min. The mean operative time in the conventional group was 60.06 + 3.74 min.; in the custom treatment group it was 42.24 + 1.29 min (p < 0.001). The difference between planned and obtained chin changes in cases of advancement or retrusion was not statistically significant (p = 0.125; p = 0.216). In cases of chin rotation due to asymmetry, guided and personalized surgery was superior to conventional surgery (p < 0.01). The mean hospital stay was equal in both groups. A decrease in surgical complications was observed in the group undergoing VSP and customized treatment.

CONCLUSIONS

Multi-stage implementation of VSP with CAD-CAM cutting guides, STL models, and patient-specific plates increased the accuracy of the genioplasty surgery, particularly in cases of chin asymmetry, reducing operation time and potential complications.

Full-Digital Customized Meshes in Guided Bone Regeneration Procedures: A Scoping Review

Meshes, especially titanium ones, are being widely applied in oral surgery. In guided bone regeneration (GBR) procedures, their use is often paired with membranes, being resorbable or non-resorbable. However, they present some limitations, such as difficulty in the treatment of severe bone defects, alongside frequent mesh exposure. Customized meshes, produced by a full-digital process, have been recently introduced in GBR procedures. Therefore, the focus of the present review is to describe the main findings in recent years of clinical trials regarding patient-specific mesh produced by CAD/CAM and 3D printing workflow, made in titanium or even PEEK, applied to GBR surgeries. The purpose is to analyze their clinical management, advantages, and complications. This scoping review considered randomized clinical trials, observational studies, cohort studies, and case series/case reports studies. Studies that did not meet inclusion criteria were excluded. The preferred reporting items for scoping reviews (PRISMA-ScR) consensus was followed. A total of 15 studies were selected for this review. Based on the studies included, the literature suggests that meshes produced by a digital process are used to restore complex and severe bone defects. Moreover, they give satisfactory aesthetic results and fit the defects, counteracting grid exposure. However, more clinical trials should be conducted to evaluate long-term results, the rate of complications, and new materials for mesh manufacturing.

Prosthetically guided mandibular reconstruction using a fibula free flap: three-dimensional Bologna plate, an alternative to the double-barrel technique

The fibula free flap represents the gold standard for mandibular reconstruction. However, when harvested as a single barrel, this flap does not allow the native mandibular height to be restored, which is required for implant-supported dental rehabilitation of the patient. The aim of this study was to present a new design for a patient-specific three-dimensionally printed reconstructive plate (3DBO-PSI) that positions the fibula bone at the height of the resected mandibular alveolar bone while restoring the mandibular profile to ensure a correct morphological outcome. Twenty patients were enrolled prospectively between January 2019 and May 2022. All patients underwent a segmental mandibular resection and prosthetically guided reconstruction making use of a fibula free flap supported by the 3DBO-PSI. The mean follow-up period was 20 months. All microvascular and implant-related complications were recorded. Microvascular failure occurred in two patients. No PSI-related complications were recorded during the postoperative follow-up. The proposed reconstructive method was found to be reliable and reproducible. In all treated patients, the bony flap appeared to be adequately positioned to maintain the preoperative intermaxillary relationship, as planned. To date, dental rehabilitation has been completed in seven patients.

Influence of Radiotherapy on Ossification of Vascularized Osseous Reconstruction of the Jaw: A Radiological Retrospective Cohort Study Based on Panoramic Radiographs

Background: The aim of this study was to evaluate the impact of irradiation and time of irradiation on the ossification of jaws reconstructed with free bone grafts. Methods: In total, 100 reconstructions of the jaw were retrospectively evaluated for ossification between bone segments by two raters based on postoperative panoramic radiographs (immediate postOP, approximately 6, 12 and 24 months follow-up). Three subgroups were divided according to the time of irradiation: preoperative radiation therapy (n = 41), postoperative radiation therapy (n = 26) and patients without any radiation therapy (n = 33) as the control group. Ossification time and influencing factors were documented. Results: The fastest ossification with a median of 304 ± 37 days was observed (p < 0.001) in the nonirradiated control group. No significant difference (p = 0.087) in ossification was found between the pre- (447 ± 136 days) and postoperative (510 ± 112 days) radiation groups. Ossification between two graft segments (336 ± 38 days) showed significantly (p < 0.001) faster ossification than between the original and grafted bone (448 ± 85 days). Moreover, closer initial contact between the segments resulted in faster ossification (p < 0.001). When analyzing cofactors, tobacco consumption was the only negative factor aggravating ossification (p = 0.006). Conclusion: Head and neck radiation corresponded with the impaired and prolonged ossification of jaw reconstructions with free bone grafts. There was no difference in ossification if radiotherapy was performed before or after reconstructive surgery. A close bony contact was particularly important for ossification between the original and grafted bone.

Virtual Surgical Planning and Customized Subperiosteal Titanium Maxillary Implant (CSTMI) for Three Dimensional Reconstruction and Dental Implants of Maxillary Defects after Oncological Resection: Case Series

Maxillectomies cause malocclusion, masticatory disorders, swallowing disorders and poor nasolabial projection, with consequent esthetic and functional sequelae. Reconstruction can be achieved with conventional approaches, such as closure of the maxillary defect by microvascular free flap surgery or prosthetic obturation. Four patients with segmental maxillary defects that had been reconstructed with customized subperiosteal titanium maxillary implants (CSTMI) through virtual surgical planning (VSP), STL models and CAD/CAM titanium mesh were included. The smallest maxillary defect was 4.1 cm and the largest defect was 9.6 cm, with an average of 7.1 cm. The reconstructed maxillary vertical dimension ranged from 9.3 mm to 17.4 mm, with a mean of 13.17 mm. The transverse dimension of the maxilla at the crestal level was attempted to be reconstructed based on the pre-excision CT scan, and these measurements ranged from 6.5 mm in the premaxilla area to 14.6 mm at the posterior level. All patients were rehabilitated with a fixed prosthesis on subperiosteal implants with good esthetic and functional results. In conclusion, we believe that customized subperiosteal titanium maxillary implants (CSTMI) are a safe alternative for maxillary defects reconstruction, allowing for simultaneous dental rehabilitation while restoring midface projection. Nonetheless, prospective and randomized trials are required with long-term follow-up, to assess its long-term performance and safety.

Mandibular Reconstruction With Fibula Flap and Dental Implants Through Virtual Surgical Planning and Three Different Techniques: Double-Barrel Flap, Implant Dynamic Navigation and CAD/CAM Mesh With Iliac Crest Graft

Introduction

Vertical discrepancy between the fibula flap and the native mandible results in difficult prosthetic rehabilitation. The aim of this study was to evaluate the outcomes of 3D reconstruction of the mandible in oncologic patients using three different techniques through virtual surgical planning (VSP), cutting guides, customized titanium mesh and plates with CAD/CAM technology, STL models and intraoperative dynamic navigation for implant placement. Material and methods

Material and Methods

Three different techniques for mandibular reconstruction and implant rehabilitation were performed in 14 oncologic patients. Five patients (36%) underwent VSP, cutting guides, STL models and a customized double-barrel titanium plate with a double-barrel flap and immediate implants. In six patients (43%), VSP, STL models and a custom-made titanium mesh (CAD/CAM) for 3D reconstruction with iliac crest graft over a fibula flap with deferred dental implants were performed. Three patients (21%) underwent VSP with cutting guides and customized titanium plates for mandibular reconstruction and implant rehabilitation using intraoperative dynamic navigation was accomplished. Vertical bone reconstruction, peri-implant bone resorption, implant success rate, effects of radiotherapy in vertical reconstruction, bone resorption and implant failure, mastication, aesthetic result and dysphagia were evaluated.

Results

Significant differences in bone growth between the double-barrel technique and iliac crest graft with titanium mesh technique were found (p<0.002). Regarding bone resorption, there were no significant differences between the techniques (p=0.11). 60 implants were placed with an osseointegration rate of 91.49%. Five implants were lost during the osseointegration period (8%). Peri-implant bone resorption was measured with a mean of 1.27 mm. There was no significant difference between the vertical gain technique used and implant survival (p>0.385). Implant survival rates were higher in non-irradiated patients (p<0.017). All patients were rehabilitated with a fixed implant-supported prosthesis reporting a regular diet (80%), normal swallowing (85.7%) and excellent aesthetic results.

Conclusions

Multi-stage implementation of VSP, STL models and cutting guides, CAD/CAM technology, customized plates and in-house dynamic implant navigation for mandibular defects increases bone-to-bone contact, resolves vertical discrepancy and improves operative efficiency with reduced complication rates and minimal bone resorption. It provides accurate reconstruction that optimizes implant placement, thereby improving facial symmetry, aesthetics and function.

Intraosseous Venous Malformation of the Zygomatic Bone: Comparison between Virtual Surgical Planning and Standard Surgery with Review of the Literature

Intraosseous venous malformations affecting the zygomatic bone are infrequent. Primary reconstruction is usually accomplished with calvarial grafts, although the use of virtual surgical planning, cutting guides and patient-specific implants (PSI) have had a major development in recent years. A retrospective study was designed and implemented in patients diagnosed with intraosseous venous malformation during 2006–2021, and a review of the scientific literature was also performed to clarify diagnostic terms. Eight patients were treated, differentiating two groups according to the technique: four patients were treated through standard surgery with resection and primary reconstruction of the defect with calvarial graft, and four patients underwent resection and primary reconstruction through virtual surgical planning (VSP), cutting guides, STL models developed with CAD-CAM technology and PSI (titanium or Polyether-ether-ketone). In the group treated with standard surgery, 75% of the patients developed sequelae or morbidity associated with this technique. The operation time ranged from 175 min to 210 min (average 188.7 min), the length of hospital ranged from 4 days to 6 days (average 4.75 days) and the postoperative CT scan showed a defect surface coverage of 79.75%. The aesthetic results were “excellent” in 25% of the patients, “good” in 50% and “poor” in 25%. In the VSP group, 25% presented sequelae associated with surgical treatment. The operation time ranged from 99 min to 143 min (average 121 min), the length of hospital stay ranged from 1 to 2 days (average of 1.75 days) and 75% of the patients reported “excellent” results. Postoperative CT scan showed 100% coverage of the defect surface in the VSP group. The multi-stage implementation of virtual surgical planning with cutting guides, STL models and patient-specific implants increases the reconstructive accuracy in the treatment of patients diagnosed with intraosseous venous malformation of the zygomatic bone, reducing sequelae, operation time and average hospital stay, providing a better cover of the defect, and improving the precision of the reconstruction and the aesthetic results compared to standard technique.