Horizontal ridge reconstruction of the anterior maxilla using customized allogeneic bone blocks with a minimally invasive technique - a case series

Maxillary rehabilitation after zygomatic implant sequelae using custom subperiosteal implants: A case study

Despite technological advancements, maxillary rehabilitation remains a significant challenge in Oral and Maxillofacial Surgery. This paper presents the case of a patient who underwent multiple previous procedures for prosthetic rehabilitation without achieving the desired results. The most recent intervention, which resulted in some sequelae, involved the placement of bilateral zygomatic implants. After unsuccessful attempts to maintain these implants, the decision was made to remove them and place a custom subperiosteal implant, produced via additive manufacturing. The patient has now been successfully rehabilitated with these implants for over a year, with no complaints and a notable improvement in her quality of life. The rehabilitation of severely atrophic maxillae using custom subperiosteal implants has proven to be an excellent alternative, offering predictability, the possibility of virtual planning and simulation, and the ability to rehabilitate extensive bone defects.

Demineralized, Freeze-Dried Allogeneic Bone Blocks With Suture Fixation Technique for Reconstruction of Maxillary Alveolar Bone Deficiency: A Case Series

This study aims to evaluate the clinical outcomes of using demineralized, freeze-dried allogeneic bone blocks (DFDABB) combined with the periosteal vertical mattress suture (PVMS) technique for the reconstruction of severe horizontal alveolar bone deficiencies in the maxilla. In continuous horizontal maxillary defects cases, bone augmentation was performed using DFDABB and deproteinized bovine bone matrix (DBBM) filling the interstice. Subsequently, a resorbable collagen membrane was carefully placed over the graft surface, and both the membrane and bone graft were firmly secured using the PVMS technique. Linear changes were assessed through superimposed cone-beam computerized tomography scans obtained before the operation and after a healing period of 6-10 months. A total of 7 female patients with 10 bone blocks and 13 implants were included in this study. One of the wounds was slightly ruptured postoperatively without infection, and all implants showed successful osseointegration. The average alveolar ridge width at a point 5 mm below the crest was 4.52 ± 2.03 mm before bone graft and 9.79 ± 1.57 mm after implantation with an average increase of 5.26 ± 1.97 mm. Similarly, at a point 10 mm below the crest, the pregraft alveolar ridge width measured 7.23 ± 3.60 mm, and postimplantation, it expanded to 11.81 ± 2.90 mm, showing an average gain of 4.58 ± 2.01 mm. This case series demonstrates the successful application of DFDABB combined with the PVMS technique to achieve adequate bone width for implantation at severe continuous horizontal bone deficiency of the maxilla. DFDABB with the PVMS technique resulted in superior horizontal bone gain during maxillary bone augmentation with horizontal continuity deficiency. However, further studies are necessary to validate these findings.

Digital planning and bone regenerative technologies: A narrative review

OBJECTIVES

The aim of this narrative review was to explore the application of digital technologies (DT) for the simplification and improvement of bone augmentation procedures in advanced implant dentistry.

MATERIAL AND METHODS

A search on electronic databases was performed to identify systematic reviews, meta-analyses, randomized and non-randomized controlled trials, prospective/retrospective case series, and case reports related to the application of DT in advanced implant dentistry.

RESULTS

Seventy-nine articles were included. Potential fields of application of DT are the following: 1) the use of intra-oral scanners for the definition of soft tissue profile and the residual dentition; 2) the use of dental lab CAD (computer-aided design) software to create a digital wax-up replicating the ideal ridge and tooth morphology; 3) the matching of STL (Standard Triangulation Language) files with DICOM (DIgital COmmunication in Medicine) files from CBCTs with a dedicated software; 4) the production of stereolithographic 3D models reproducing the jaws and the bone defects; 5) the creation of surgical templates to guide implant placement and augmentation procedures; 6) the production of customized meshes for bone regeneration; and 7) the use of static or dynamic computer-aided implant placement.

CONCLUSIONS

Results from this narrative review seem to demonstrate that the use of a partially or fully digital workflow can be successfully used also in advanced implant dentistry. However, the number of studies (in particular RCTs) focused on the use of a fully digital workflow in advanced implant dentistry is still limited and more studies are needed to properly evaluate the potentials of DT.

Three-Dimensional Printed Patient-Specific Vestibular Augmentation: A Case Report

Background: The anterior maxilla is challenging regarding aesthetic rehabilitation. Current bone augmentation techniques are complex and 3D-printed bioceramic bone grafts can simplify the intervention. Aim: A four-teeth defect in the anterior maxilla was reconstructed with a 3D-printed synthetic patient-specific bone graft in a staged approach for dental implant delivery. Methods: The bone graft was designed using Cone-Beam Computed Tomography (CBCT) images. The bone graft was immobilized with fixation screws. Bone augmentation was measured on CBCT images at 11 days and 8 and 13 months post-surgery. A biopsy sample was retrieved at reentry (10 months post-augmentation) and evaluated by histological and micro-computed tomography assessments. The definitive prosthesis was delivered 5 months post-reentry and the patient attended a visit 1-year post-loading. Results: A total bone width of 8 mm was achieved (3.7 mm horizontal bone gain). The reconstructed bone remained stable during the healing period and was sufficient for placing two dental implants (with an insertion torque > 35 N·cm). The fractions of new bone, bone graft, and soft tissue in the biopsy were 40.77%, 41.51%, and 17.72%, respectively. The histological assessment showed no signs of encapsulation, and mature bone was found in close contact with the graft, indicating adequate biocompatibility and suggesting osteoconductive properties of the graft. At 1-year post-loading, the soft tissues were healthy, and the dental implants were stable. Conclusions: The anterior maxilla's horizontal ridge can be reconstructed using a synthetic patient-specific 3D-printed bone graft in a staged approach for implant placement. The dental implants were stable and successful 1-year post-loading.

Clinical and Biological Validation of an Allogeneous Cancellous Bone Block for Alveolar Maxillary Ridge Reconstruction: A Case Series

This exploratory case series clinically and histologically investigated the performance of allogeneic cancellous freeze-dried bone allograft (FDBA) bone blocks (Maxgraft®) for the lateral augmentation of local alveolar defects in the posterior maxilla as part of two-staged implant therapy. Five patients receiving eight implants 5 months after block augmentation with a follow-up period of up to 3 years were documented and analyzed. Horizontal alveolar dimensions before and 5 months after block augmentation were quantified using CBCT. Radiographic marginal bone level changes were quantified at implant placement, loading, and 1 year post-placement. Graft integration and resorption were histologically qualitatively evaluated from core biopsies retrieved at implant placement. Block augmentations resulted in a pronounced horizontal median bone gain of 7.0 (5.5 to 7.8) mm. Marginal implant bone levels in block-augmented bone remained constant over the 1 year follow-up period. Block grafts appeared histologically well integrated. Histologic analysis also revealed signs of progressive resorption and new bone formation at the lateral aspects of the grafts. The results of this case series support using Maxgraft® cancellous FDBA blocks as suitable materials for the lateral augmentation of local alveolar defects.

Customized three-dimensional printed ceramic bone grafts for osseous defects: a prospective randomized study

Ridge resorption can result in insufficient bone volume for implant surgery, necessitating bone substitutes to restore the resorption area. Recent advances in computer-aided design and manufacturing enable the use of alloplastic bone graft materials with customizable compositions or shapes. This randomized study evaluated the clinical effectiveness of a customized three-dimensional (3D) printed alloplastic bone material. Sixty patients requiring guided bone regeneration for implant installation following tooth extraction due to alveolar bone resorption were recruited at two institutions. The participants were randomly allocated to either a group that received 3D-printed patient-customized bone graft material or a group that received conventional block bone graft material. Implant installation with bone harvesting was performed approximately 5 months after bone grafting. Histological and radiological assessments of the harvested bone area were performed. The experimental group had a significantly higher percent bone volume and a smaller tissue surface than the control group. Bone volume, bone surface, bone surface/volume ratio, bone surface density (bone surface/total volume), and bone mineral density did not differ significantly between groups. Patient-customized bone graft materials offer convenience and reduce patient discomfort. The findings suggest 3D-printed patient-customized bone graft materials could be used as an alternative for simpler bone grafting procedures.

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.

Application of biodegradable Patient-specific scaffolds for maxillofacial bone regeneration: a scoping review of clinical studies

This study aimed to systematically review clinical studies in which biodegradable patient-specific scaffolds were used for bone regeneration. Studies in which biodegradable scaffolds were fabricated through computer-assisted design and computer-assisted manufacturing (CAD-CAM) procedures were included. Those that applied non-biodegradable materials or used biodegradable materials in a condensable powder or block form were excluded. Among a total of 26 included studies, 11 used customised allogeneic bone blocks, five used polycaprolactone (PCL)-containing scaffolds, four used hydroxyapatite (HA) scaffolds, and four biphasic calcium phosphate (BCP). The majority of the studies applied scaffolds for minor intraoral defects. All the large defects were reconstructed with polymer-containing scaffolds. Results of the included studies showed partial to complete filling of the defect following the application of biodegradable scaffolds. However, limited graft exposure was reported when using PCL, BCP, and HA scaffolds. Tissue engineering can be considered a potential method for the treatment of maxillofacial bone defects. However, more evidence is required, especially for the application of biodegradable scaffolds in large defects.

Clinical feasibility evaluation of a digital workflow of prosthetically oriented onlay bone grafting for horizontal alveolar augmentation: a prospective pilot study

BACKGROUND

Onlay bone grafting is considered highly reliable for reconstructing severe horizontal bone defects. A critical problem is how to achieve precise position of the bone block to control alveolar ridge dimensions. This research aims to establish a digital workflow for prosthetically oriented onlay bone grafting and evaluate its accuracy and efficiency.

METHODS

This prospective pilot study investigated eight patients who required implant restoration in the esthetic area with horizontal alveolar bone defects. The workflow includes preoperative virtual planning, design and manufacture of patient-specific templates, bone grafting surgery, and implant insertion. Primary outcomes were graft accuracy, defined by root mean square estimate (RMSE) values between preoperatively designed and actual implanted outer contours of bone blocks. Secondary outcomes were bone graft and implant success rates. Besides, the surgeons used the visual analog scale (VAS) to rate the intuitiveness, ease of understanding, and helpfulness of the workflow.

RESULTS

No bone grafts or implants failed in any of the eight patients, resulting in a 100% success rate. The RMSE values between the preoperative design and the implanted outer contour of bone blocks were 0.41 ± 0.15 mm. The digital approach showed advantages in intuitiveness (9.3 ± 0.5), understanding (9.0 ± 0.5), and helpfulness (8.4 ± 1.1) according to surgeons' VAS scores.

CONCLUSIONS

A digital workflow provided encouraging results, in terms of accuracy and efficacy, for horizontal bone augmentation.

TRIAL REGISTRATION

This study was registered in the National Clinical Trials Registry in 16/02/2023 under the identification number ChiCTR2300068361.

Possible Applications for a Biodegradable Magnesium Membrane in Alveolar Ridge Augmentation-Retrospective Case Report with Two Years of Follow-Up

Background and Objectives: A rigid, resorbable magnesium membrane was recently developed, combining the advantages of resorbable and non-resorbable membranes. Our aim was to describe the application of this membrane for guided bone regeneration (GBR). Materials and Methods: This case report described the treatment and 3D evaluation of two cases utilizing a resorbable magnesium barrier membrane. In Case #1, GBR was performed with a bilayer tunnel flap. The magnesium barrier was placed fixed subperiosteally through remote vertical incisions. In Case #2, GBR was performed using a split-thickness flap design. Volumetric and linear hard tissue alterations were assessed by 3D cone-beam computed tomography subtraction analysis, as well as with conventional intraoral radiography. Results: Case #1 showed a volumetric hard tissue gain of 0.12 cm3, whereas Case #2 presented a 0.36 cm3 hard tissue gain. No marginal peri-implant hard tissue loss could be detected at the two-year follow-up. Conclusions: The application of conventional resorbable collagen membranes would be difficult in either of the cases presented. However, the rigid structure of the magnesium membrane allowed for the limitations of conventional resorbable membranes to be overcome.

Custom-made computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) synthetic bone grafts for alveolar ridge augmentation: A retrospective clinical study with 3 years of follow-up

PURPOSE

To report on the results obtained with computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) custom-made synthetic hydroxyapatite/beta-tricalcium-phosphate (HA/beta-TCP) bone grafts in alveolar ridge augmentation for dental implant placement.

METHODS

The procedure included: (1) cone-beam computed tomography (CBCT) of the bone defect; (2) virtual design of the custom-made onlay bone grafts; (3) milling of grafts from a pre-formed block of synthetic HA/beta-TCP; and (4) bone reconstructive surgery. Implants were placed 8 months later. The patients were followed for 3 years. The study outcomes were: (1) intra- and immediate post-operative complications; (2) 8-month vertical and horizontal bone gain; (3) implant survival; (4) implant-crown success; and (5) peri-implant marginal bone loss (MBL).

RESULTS

Twenty-six patients underwent ridge augmentation with custom-made CAD/CAM HA/beta-TCP onlay grafts. Eight months later, these patients were rehabilitated with dental implants. During surgery, 25/26 (96.1%) of the grafts adapted well to the bone defect. Immediate post-operative complications were pain and swelling (2/26 patients: 7.6%), and bone graft exposure (3/26: 11.5%); one exposure led to infection, removal of the graft, and failure of the procedure. Excellent integration of the other grafts was observed 8 months after the regenerative procedure, with mean vertical and horizontal bone gains of 2.10 mm (± 0.35) and 2.96 mm (± 0.45), respectively. Twenty-five implants were placed and restored with single crowns. Three years later, all implants were in function. The 3-year implant crown success rate and peri-implant MBL were 92.0% and 0.7 mm (±0.19), respectively.

CONCLUSIONS

With custom-made CAD/CAM synthetic HA/beta-TCP onlay grafts reconstruction of small vertical and/or horizontal defects of the alveolar ridge was obtained; this enabled implant placement, with high implant-crown success rate after 3 years. Further studies are needed to validate this technique.

STATEMENT OF CLINICAL RELEVANCE

Custom-made CAD/CAM synthetic HA/beta-TCP onlay grafts may represent an option for regeneration of small bone defects prior to implant placement.

Three-dimensional printing of clinical scale and personalized calcium phosphate scaffolds for alveolar bone reconstruction

OBJECTIVE

Alveolar bone defects can be highly variable in their morphology and, as the defect size increases, they become more challenging to treat with currently available therapeutics and biomaterials. This investigation sought to devise a protocol for fabricating customized clinical scale and patient-specific, bioceramic scaffolds for reconstruction of large alveolar bone defects.

METHODS

Two types of calcium phosphate (CaP)-based bioceramic scaffolds (alginate/β-TCP and hydroxyapatite/α-TCP, hereafter referred to as hybrid CaP and Osteoink™, respectively) were designed, 3D printed, and their biocompatibility with alveolar bone marrow stem cells and mechanical properties were determined. Following scaffold optimization, a workflow was developed to use cone beam computed tomographic (CBCT) imaging to design and 3D print, defect-specific bioceramic scaffolds for clinical-scale bone defects.

RESULTS

Osteoink™ scaffolds had the highest compressive strength when compared to hybrid CaP with different infill orientation. In cell culture medium, hybrid CaP degradation resulted in decreased pH (6.3) and toxicity to stem cells; however, OsteoInk™ scaffolds maintained a stable pH (7.2) in culture and passed the ISO standard for cytotoxicity. Finally, a clinically feasible laboratory workflow was developed and evaluated using CBCT imaging to engineer customized and defect-specific CaP scaffolds using OsteoInk™. It was determined that printed scaffolds had a high degree of accuracy to fit the respective clinical defects for which they were designed (0.27 mm morphological deviation of printed scaffolds from digital design).

SIGNIFICANCE

From patient to patient, large alveolar bone defects are difficult to treat due to high variability in their complex morphologies and architecture. Our findings shows that Osteoink™ is a biocompatible material for 3D printing of clinically acceptable, patient-specific scaffolds with precision-fit for use in alveolar bone reconstructive procedures. Collectively, emerging digital technologies including CBCT imaging, 3D surgical planning, and (bio)printing can be integrated to address this unmet clinical challenge.

Biomechanical Examination of Osseointegration of Titanium Implants Placed Simultaneously With Allogeneic Bone Transfer

ABSTRACT

The aim of this study was to conduct a biomechanical analysis of the early period bone-implant connection of titanium implants in the same type of subjects. In this study, 18 Sprague Dawley rats were used. Four rats were killed to provide the allogeneic bone before the experiment, and the remaining were divided into a control group and an experimental allogeneic bone transfer group. Titanium machined surfaced implants were integrated in tibias in the controls and in the experimental group; simultaneously, implants were integrated into allogeneic bone in the bone transfer group. All the rats were sacrificed 14 days later. Bone tissues with titanium implants were removed for biomechanical analysis, which found that the resistance to force of the control group and the allogeneic graft group was 2.04 and 2.00 Newtons, respectively, and there was no significant difference between the two groups at 14 days, although numerically a higher figure was detected in the controls (P > 0.05). It was concluded, within the limitations of this study, that an allogeneic bone transfer can be used as an alternative to an autogenous graft.

Implant repositioning with segmental osteotomy

INTRODUCTION

The aim of this study is to assess a pioneering technique for atrophic premaxilla restoration. The objective is to reposition an implant reconstruction zone into a position both anatomically and physiologically suitable for occlusal function. Indeed, unlike the other few articles published on the correctional osteotomy of the implant in an inadequate situation, we have planned here an initially «unsuitable» insertion in order to benefit of the available bone mass.

MATERIAL AND METHOD

3 patients aged 14-20 years old (1 woman and 2 men) were operated on at the maxillo-facial department of Lille 2 University Hospital for partial implant-prosthetic rehabilitation on atrophic maxillary and/or mandibular sector. 13 implants were seated (85% in the maxilla) in the native bone then moved subsequently by segmental osteotomy.

RESULTS

The patients were assessed both clinically and radiologically according to the functional and aesthetic criteria of implant-prosthetic restoration. Functionally, a biomechanically favourable implant/number of teeth ratio (80%) was achieved, with consistent occlusal relationships (centric positioning of the midline point and absence of crossbite) in 100% of cases. Aesthetically, the screw access hole is systematically non-apparent (100%) but has a prosthetically substituted reduced gingivo-alveolar architecture.

DISCUSSION

These observations suggest that implant repositioning with segmental osteotomy allows for atrophic premaxilla restoration in implanted bone volume whatever the initial angulation. Peri-implant aesthetic difficulties are not specific to the technique suggested here but are quite common to all premaxilla reconstruction techniques. Lastly, this group of three patients is not enough to be conclusive, and a larger group would be necessary to validate this type of management.

Design Techniques to Optimize the Scaffold Performance: Freeze-dried Bone Custom-made Allografts for Maxillary Alveolar Horizontal Ridge Augmentation

The purpose of the current investigation was to evaluate the clinical success of horizontal ridge augmentation in severely atrophic maxilla (Cawood and Howell class IV) using freeze-dried custom made bone harvested from the tibial hemiplateau of cadaver donors, and to analyze the marginal bone level gain prior to dental implant placement at nine months subsequent to bone grafting and before prosthetic rehabilitation. A 52-year-old woman received custom made bone grafts. The patient underwent CT scans two weeks prior and nine months after surgery for graft volume and density analysis. The clinical and radiographic bone observations showed a very low rate of resorption after bone graft and implant placement. The custom-made allograft material was a highly effective modality for restoring the alveolar horizontal ridge, resulting in a reduction of the need to obtain autogenous bone from a secondary site with predictable procedure. Further studies are needed to investigate its behavior at longer time periods.

Assessment of clinical outcomes and histomorphometric findings in alveolar ridge augmentation procedures with allogeneic bone block grafts: A systematic review and meta-analysis

BACKGROUND

This systematic literature review aimed to evaluate the efficacy of allogeneic bone blocks for ridge augmentation by assessing block survival rates and subsequent implant survival, including post-surgical complications and histomorphometric analysis.

MATERIAL AND METHODS

An electronic and manual search among references, was conducted up to April 2019 by two independent authors. Inclusion criteria were: human clinical trials in which the outcomes of allogeneic bone block grafts were evaluated by means of their survival rates and subsequent implant success rates.

RESULTS

Seven articles fulfilled the inclusion criteria and were analyzed. A total of 323 allogeneic block grafts were monitored for a minimum of 12 months follow-up after surgery, of which thirteen (4.02%) failed. Regarding the cumulative implant survival rate, the weighted mean was 97.36%, computed from 501 implants. Histologic and histomorphometric analysis showed that allogeneic block grafts presented some clinical and microstructural differences in comparison with autologous block grafts.

CONCLUSIONS

Atrophic alveolar crest reconstruction with allogeneic bone block grafts would appear a feasible alternative to autologous bone block grafts, obtaining a low block graft failure rate, similar implant survival rate and fewer postoperative complications. Further investigations generating long term data are needed to confirm these findings.

Custom-made 3D printed subperiosteal titanium implants for the prosthetic restoration of the atrophic posterior mandible of elderly patients: a case series

Purpose

To present the application of custom-made 3D-printed subperiosteal implants for fixed prosthetic restoration of the atrophic posterior mandible of elderly patients.

Methods

Between January 2017 and June 2018, all partially edentulous patients aged over 65 years, with two or more missing teeth in the posterior atrophic mandible, and who did not want to undergo bone regenerative procedures, were included in this study. These patients were rehabilitated with custom-made subperiosteal implants, designed from cone beam computed tomography (CBCT) and fabricated in titanium by means of direct metal laser sintering (DMLS). The outcome measures were fit and stability of the implants at placement, duration of the intervention, implant survival, and early and late complications. All patients were followed for 1 year after surgery.

Results

Ten patients (four males, six females; mean age 69.6, SD ± 2.8, median 69, 95% CI 67.9–71.6) were included in the study. The fit of the implants was satisfactory, with a mean rating of 7 out of 10 (SD ± 1.6, median 7, 95% CI 6–8). Only two implants had insufficient fit, because of the presence of scattering in the CBCT; however, they were adapted to the sites during the interventions. The mean duration of the intervention was 44.3 min (SD ± 19.4, median 37, 95% CI 32.3–56.3). At the one-year follow-up, no implants were lost (survival rate 100%). One implant presented immediate postoperative complications with pain, discomfort and swelling, and two patients experienced late complications, having their provisional restorations fractured during the temporisation phase. All these complications were minor in nature, but the final complication rate amounted to 30% (three of ten patients).

Conclusions

Although this study has limits (small patient sample and short follow-up), DMLS has proven to be an effective method for fabricating accurate subperiosteal implants, with high survival rates. This may represent an alternative treatment procedure in elderly patients with a severely atrophic posterior mandible, since it allows avoidance of regenerative bone therapies. Further studies are needed to confirm these outcomes.

Osseous ingrowth in allogeneic bone blocks applied for vertical bone augmentation: a preclinical randomised controlled study

OBJECTIVES

The aim of the present study was the qualitative and quantitative evaluation of osseous graft consolidation using allogeneic bone blocks for vertical bone augmentation in an animal model.

MATERIAL AND METHODS

Standardised allogeneic and autologous bone blocks were fixed on the frontal skull of 20 adult female pigs and covered with a resorbable collagen membrane. Animals were sacrificed after 2 and 6 months. Specimens were histologically and histomorphometrically analysed focusing on the amount of vital bone, residual bone substitute material and connective tissue. Furthermore, the amount of expression of bone matrix proteins (collagen type I and osteocalcin) and de novo vessel formation (von Willebrand factor) were quantified by immunohistochemistry.

RESULTS

Significantly more allogeneic bone blocks failed for both evaluation time points (p < 0.05). Allogeneic blocks showed significantly less vital bone with more connective tissue formation compared to autologous bone blocks. Increased vessel formation could be detected for both evaluation time points in the contact area of autologous bone with local bone. The expression of collagen type I and osteocalcin was significantly lower in the allogeneic bone graft.

CONCLUSIONS

Allogeneic cancellous bone blocks showed a significantly higher failure rate compared to autologous bone blocks. Allogeneic bone blocks seemed to negatively affect bone formation or negatively influence the host in the long term, and increased connective tissue formation and block loss should be anticipated.

CLINICAL RELEVANCE

In order to maintain patient safety and treatment success clinicians should be persuaded to make a conscious choice of the applied biomaterials with regard to their components and structure.

Maxillary reconstruction using tunneling flap technique with 3D custom-made titanium mesh plate and particulate cancellous bone and marrow graft: a case report

Background

Reconstructive surgery is often required for tumors of the oral and maxillofacial region, irrespective of whether they are benign or malignant, the area involved, and the tumor size. Recently, three-dimensional (3D) models are increasingly used in reconstructive surgery. However, these models have rarely been adapted for the fabrication of custom-made reconstruction materials. In this report, we present a case of maxillary reconstruction using a laboratory-engineered, custom-made mesh plate from a 3D model.

Case presentation

The patient was a 56-year-old female, who had undergone maxillary resection in 2011 for intraoral squamous cell carcinoma that presented as a swelling of the anterior maxillary gingiva. Five years later, there was no recurrence of the malignant tumor and a maxillary reconstruction was planned. Computed tomography (CT) revealed a large bony defect in the dental-alveolar area of the anterior maxilla. Using the CT data, a 3D model of the maxilla was prepared, and the site of reconstruction determined. A custom-made mesh plate was fabricated using the 3D model (Okada Medical Supply, Tokyo, Japan). We performed the reconstruction using the custom-made titanium mesh plate and the particulate cancellous bone and marrow graft from her iliac bone. We employed the tunneling flap technique without alveolar crest incision, to prevent surgical wound dehiscence, mesh exposure, and alveolar bone loss. Ten months later, three dental implants were inserted in the graft. Before the final crown setting, we performed a gingivoplasty with palate mucosal graft. The patient has expressed total satisfaction with both the functional and esthetic outcomes of the procedure.

Conclusion

We have successfully performed a maxillary and dental reconstruction using a custom-made, pre-bent titanium mesh plate.

Biomaterial-based bone regeneration and soft tissue management of the individualized 3D-titanium mesh: An alternative concept to autologous transplantation and flap mobilization

Three-dimensional augmentation in severely atrophic bone and after cancer resection is a challenging clinical indication that is mostly solved using autologous bone transplantation. The development of the digital technique along with the additive manufacturing and three-dimensional (3D) printing opened new avenues for reconstructive oral and maxillofacial surgery. Therefore, patient-specific titanium mesh is a novel means of stabilizing the augmentation region using particulate bone substitute materials (BSMs) combined with autologous bone as a minimally invasive concept. However, dehiscence is a frequently reported complication in this field. Therefore, the aim of the present case series was to introduce a biomaterial-based regenerative concept in terms of exposed open healing to overcome the dehiscence related to 3D-titanium meshes. Additionally, this case series presents a novel protocol using a combination of xenogeneic BSMs with an autologous blood concentrate system (platelet-rich fibrin [PRF]) and collagen matrices without any autologous transplantation. Seven patients with alveolar ridge atrophy with different etiologies (cancer resection, severe atrophy after tooth loss, aplasia, trauma, implant infections) were treated using the open-healing concept. Therefore, after 3D augmentation using the described biomaterials, the flap margins were approximated, and the gap between the flap margins was bridged using a collagen matrix loaded with liquid PRF that was then covered by either a PTFE-based membrane or sterile latex. No periosteum splitting was performed at any time point. After a healing period of 4-8 months, all patients received dental implants as virtually planned. Bone biopsies were performed during dental insertion for histological evaluation. The augmentation area displayed a vital and well-vascularized newly formed bone that incorporated the BSM granules to build a hybrid bone. Additionally, open healing resulted in newly formed soft tissue without any signs of scar formation or fibrosis. The regenerated soft tissue was used to build a new flap during implant insertion and showed good functional and aesthetic results after implant insertion. The open-healing concept of the regeneration of the soft tissue along with bone tissue to regenerate a harmonic implantation bed is a minimally invasive intervention without periosteum splitting or large flap mobilization. However, further controlled clinical studies are needed to evaluate this concept in a larger patient cohort to outline the potential clinical benefit.

Evaluation of the Bone Regeneration Effect of Recombinant Human Bone Morphogenic Protein-2 on Subperiosteal Bone Graft in the Rat Calvarial Model

The aim of this study was to evaluate the bone regeneration effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) on a subperiosteal bone graft in a rat model. A subperiosteal space was made on the rat calvarium, and anorganic bovine bone (ABB), ABB/low bone morphogenetic protein (BMP) (5 µg), and ABB/high BMP (50 µg) were grafted as subperiosteal bone grafts. The new bone formation parameters of bone volume (BV), bone mineral density (BMD), trabecular thickness (TbTh), and trabecular spacing (TbSp) were evaluated by microcomputed tomography (µ-CT), and a histomorphometric analysis was performed to evaluate the new bone formation area. The expression of osteogenic markers, such as bone sialoprotein (BSP) and osteocalcin, were evaluated by immunohistochemistry (IHC). The ABB/high BMP group showed significantly higher BV than the ABB/low BMP (p = 0.004) and control groups (p = 0.000) and higher TbTh than the control group (p = 0.000). The ABB/low BMP group showed significantly higher BV, BMD, and TbTh than the control group (p = 0.002, 0.042, and 0.000, respectively). The histomorphometry showed significantly higher bone formation in the ABB/low and high BMP groups than in the control group (p = 0.000). IHC showed a high expression of BSP and osteocalcin in the ABB/low and high BMP groups. Subperiosteal bone grafts with ABB and rhBMP-2 have not been studied. In our study, we confirmed that rhBMP-2 contributes to new bone formation in a subperiosteal bone graft with ABB.

Full in-Office Guided Surgery with Open Selective Tooth-Supported Templates: A Prospective Clinical Study on 20 Patients

Background: Guided implant surgery appears to have several benefits, such as the possibility of inserting flapless implants in a prosthetically driven manner, avoiding dangerous anatomical structures. However, to date, only a few surgeons routinely use guided surgery in partially edentulous patients. Aim: To present the results obtained with tooth-supported surgical templates characterized by an innovative open design with selective support, and manufactured via a full in-office procedure with a low-cost desktop 3D printer. Methods: Over a two-year period (2016–2018), all partially edentulous patients with one to three missing teeth (in maxilla and/or mandible), referred to a private dental practice for restoration with dental implants, were considered for inclusion in this prospective clinical study. An intraoral scanner (CS 3600^®, Carestream Dental) and cone beam computed tomography (CS 9300^®, Carestream Dental) were used to acquire the 3D information on the patients. Guided surgery software (SMOP^®, Swissmeda) was used to plan the surgeries and to design open, selective, tooth-supported templates that were fabricated with a stereolithographic (SLA) desktop 3D printer (XFAB2000^®, DWS). Guided implant surgeries were performed and patients were followed for a period of one year. The study outcomes were fit and stability of surgical templates, duration (time) of surgery, intra and post-operative complications, and implant stability and survival. Results: Twenty (20) partially edentulous patients (9 males, 11 females; mean age 54.4 ± 9.4 years) were included in the study; 28 open, selective, tooth-supported templates were designed with the aim of inserting 38 implants. Among the surgical templates, 24 had optimal fit and stability, three had optimal fit and sufficient stability, and only one had inadequate fit and unsatisfactory stability and was therefore not suitable for clinical use. The average time of the intervention was 15.7 ± 5.2 min per template. No intra-operative complications were reported, but one implant was not stable at placement and had to be removed. In total, 36 implants were restored with 10 two-unit fixed partial prostheses and 16 single crowns. All implants were successfully functioning at one year, even if, in two single crowns, minor prosthetic complications (abutment screw loosening) occurred. Conclusions: Full in-office guided surgery with open, selective, tooth-supported templates seem to represent a clinically predictable surgical procedure to restore partially edentulous patients. Further studies are needed to confirm these positive outcomes.

Maxillary Sinus Floor Augmentation to Enable One-Stage Implant Placement by Using Bovine Bone Substitute and Platelet-Rich Fibrin

Nowadays it is possible to perform an optimal implant placement and to achieve a good long-term prognosis for an implant-borne prosthesis in the grafted posterior maxilla. This study evaluates the efficiency of one-stage piezosurgery by using as graft material a combination of particulate bovine bone substitutes with platelet-rich fibrin to achieve sinus lift. We included in this study 14 cases of one-stage sinus lift surgeries during which we placed 30 standard implants. The mean vertical bone height gain was 10.12 mm six months after surgery, and the mean postoperative follow-up time was 43.79 months. There were no major complications during or after surgery, and all implants are in use. Therefore, it can be concluded that one-stage sinus piezosurgery using particulate bovine bone substitutes and platelet-rich fibrin can be applied as a predictable and effective technique in the treatment of the posterior edentulous maxilla ensuring 4-5 mm vertical bone height.

Lateral Sinus Floor Elevation Performed with Trapezoidal and Modified Triangular Flap Designs: A Randomized Pilot Study of Post-Operative Pain Using Thermal Infrared Imaging

Purpose: Post-operative pain and swelling are frequently observed after sinus lift procedures. The aim of the present study was the clinical evaluation of swelling and pain of two different sinus flap lift techniques using a visual analogue scale (VAS), verbal rating scale (VRS), and infrared thermal imaging (i.e., thermography). Materials Methods: A randomized controlled trial was conducted with 15 patients (30 sinuses in total) randomly allocated into two groups. For the sinuses of Group I a trapezoidal flap was used, while for Group II a modified triangular flap without anterior release was utilized. Postoperative pain was scored by means of a 100-mm VAS ranging from 0 (no pain) to 100 (worst pain imaginable), and was recorded at 2, 4, 6 and 14 days after surgery. Swelling was recorded by a verbal rating scale (VRS) and was classified into four categories: a score of 1 referred the absence of swelling, patients with intra-oral swelling in the surgical zone scored 2, any extra-oral swelling in the surgical zone scored 3, and intense swelling exhibited by extra-oral swelling extending beyond the surgical zone scored 4. The facial temperature was recorded before and after sinus augmentation, and at 2, 4, 6, and 14 days post-surgery to check the course of healing. Results: In Group I pain intensity was recorded at 2 days after surgery with a mean score of 38.67 ± 6.4 mm. Swelling was greater at 2 and 4 days, and was absent at day 6. The facial temperature difference before and after the procedure was 4.737 &deg;C ± 0.37. In Group II the pain score were lower than in Group I (p < 0.05). The score for swelling was 2 on the first and second days, and was reduced on day 4. After the second day the difference in temperature was significantly reduced as compared to the day of surgery (0.77 &deg;C); at 2 and 4 days no difference was registered. Conclusions: The results of this clinical study show the significant effectiveness of the modified triangular flap in the sinus lift procedure for reducing pain and swelling.

CAD/CAM and 3D-Printing Applications for Alveolar Ridge Augmentation

Purpose of review

CAD/CAM and 3D-printing are emerging manufacturing technologies in dentistry. In the field of alveolar ridge augmentation, graft customization utilizing these technologies can result in significant reduction of surgical time. A review of the literature on materials, techniques and applications of CAD/CAM and 3D-printing available for alveolar ridge augmentation was performed.

Recent findings

CAD/CAM applications for milling of customized block grafts of allogeneic, xenogeneic, and alloplastic origins have been reported, and currently only limited products are commercially available. 3D-printing applications are limited to alloplastic graft materials and containment shells, and have been mostly used in animal studies for optimizing biomaterials' properties.

Summary

While current data support the potential use of CAD/CAM and 3D-printing for graft customization for alveolar ridge augmentation procedures, additional research is needed on predictability and long-term stability of the grafted sites.