Vertical ridge augmentation of the atrophic posterior mandible with custom-made, computer-aided design/computer-aided manufacturing porous hydroxyapatite scaffolds

Ceramic-based 3D printed bone graft in bone tissue reconstruction: a systematic review and proportional meta-analysis of clinical studies

INTRODUCTION

This systematic review and proportional meta-analysis aims to evaluate the postoperative complication rate (CR%) of ceramic-based 3D-printed bone grafts based on the reported scientific articles conducted with human individuals.

METHODS

MEDLINE and SCOPUS were used as information sources. The synthesis of the study was carried out from studies with human individuals and the use of 3D-printed bone graft-ceramic as inclusion criteria. Cohen's kappa (κ) was calculated for interrater reliability. Qualitative analysis was performed based on the characteristics and outcomes of the individual study, and quantitative analysis was performed using proportional meta-analysis for CR%.

RESULTS

A total of 1352 records were identified through databases and resulted in 11 included studies (κ = 0.81-1.00) consisting of prospective clinical trials (64.63%), case series (16.67%), and case reports (18.18%). The overall postoperative complication rate was 14.3% (95% Cl: 0.19-53.6). The postoperative complication rate for studies conducted on the cranial defect, the maxillofacial-zygomatic defect, and the tibial-femoral defect was 2.7%, 11.1%, and 15.6%, respectively. This review also highlights common 3D printing techniques, materials, and grafs' characteristics, as well as their clinical applications.

CONCLUSIONS

Ceramic-based 3D-printed bone grafts show potential as alternatives for bone tissue reconstruction.

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.

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.

Functionalized 3D Hydroxyapatite Scaffold by Fusion Peptides-Mediated Small Extracellular Vesicles of Stem Cells for Bone Tissue Regeneration

3D printing technology offers extensive applications in tissue engineering and regenerative medicine (TERM) because it can create a three-dimensional porous structure with acceptable porosity and fine mechanical qualities that can mimic natural bone. Hydroxyapatite (HA) is commonly used as a bone repair material due to its excellent biocompatibility and osteoconductivity. Small extracellular vesicles (sEVs) derived from bone marrow mesenchymal stem cells (BMSCs) can regulate bone metabolism and stimulate the osteogenic differentiation of stem cells. This study has designed a functionalized bone regeneration scaffold (3D H-P-sEVs) by combining the biological activity of BMSCs-sEVs and the 3D-HA scaffold to improve bone regeneration. The scaffold utilizes the targeting of fusion peptides to increase the loading efficiency of sEVs. The composition, structure, mechanical properties, and in vitro degradation performance of the 3D H-P-sEVs scaffolds were examined. The composite scaffold demonstrated good biocompatibility, substantially increased the expression of osteogenic-related genes and proteins, and had a satisfactory bone integration effect in the critical skull defect model of rats. In conclusion, the combination of EVs and 3D-HA scaffold via fusion peptide provides an innovative composite scaffold for bone regeneration and repair, improving osteogenic performance.

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.

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.

The use of 3D ceramic block graft compared with autogenous block graft for rehabilitation of the atrophic maxilla: a randomized controlled clinical trial

Background

Dental implant placement may require a bone graft for vertical and horizontal alveolar ridge augmentation. Due to its osteoconduction, osteoinductive, and osteogenesis, autogenous bone graft characteristics are considered the standard gold treatment. However, autografts can promote postoperative morbidity and implicate difficulties concerning the graft adaptation to the recipient's bone since it can eventually avoid gaps. To overcome these issues, this trial will compare the performance of Plenum® Oss 3Dβ fit, an alloplastic graft, and a 3D-printed patient-specific graft based on β-tricalcium phosphate to the autograft procedure.

Methods

This is a split-mouth randomized clinical study designed to evaluate the performance of personalized (patient-specific) bioceramic bone grafts (Plenum® Oss 3Dβ fit) for bone augmentation of the atrophic anterior maxilla in comparison to the autogenous bone graft. We hypothesize that the gain and maintenance of the grafted area volume and the quality of the newly formed bone tissue after eight months postoperative with the synthetic patient-specific graft will be superior to the autogenous bone graft. To assess the quantity and the quality of bone neoformation, volumetric and histological analyses will be performed.

Discussion

The fabrication of medical devices by additive manufacturing presents advantages over conventional manufacturing processes, mostly related to the precision of geometry and anatomy. Additionally, the osteoconductive proprieties of β-tricalcium phosphate enable this synthetic bone substitute as an alternative solution over autogenous graft for bone defect reconstruction. Thus, patient-specific bone grafts can potentially improve patient satisfaction, reducing the need for autogenous bone grafts, consequently avoiding implications related to this type of treatment, such as patient morbidity.

Trial registration

This study is registered in REBEC (Registro Brasileiro de Ensaios Clínicos): RBR-76wmm3q; UTN: U1111-1272-7773. Registration date: 14 September 2021.

Supercritical Carbon Dioxide Decellularized Xenograft-3D CAD/CAM Carved Bone Matrix Personalized for Human Bone Defect Repair

About 30-50% of oral cancer patients require mandibulectomy and autologous fibula reconstruction. Autograft is the gold standard choice because of its histocompatibility; however, it requires additional surgery from the patient and with possible complications such as loss of fibula leading to calf weakening in the future. Allograft and xenograft are alternatives but are susceptible to immune response. Currently, no personalized bone xenografts are available in the market for large fascial bone defects. In addition, a large-sized complex shape bone graft cannot be produced directly from the raw material. We propose the use of porcine bones with 3D CAD/CAM carving to reconstruct a personalized, wide range and complex-shaped bone. We anticipate that patients can restore their native facial appearance after reconstruction surgery. Supercritical CO2 (SCCO2) technology was employed to remove the cells, fat and non-collagenous materials while maintaining a native collagen scaffold as a biomedical device for bone defects. We successfully developed 3D CAD/CAM carved bone matrices, followed by SCCO2 decellularization of those large-sized bones. A lock-and-key puzzle design was employed to fulfil a wide range of large and complex-shaped maxillofacial defects. To conclude, the 3D CAD/CAM carved bone matrices with lock and key puzzle Lego design were completely decellularized by SCCO2 extraction technology with intact natural collagen scaffold. In addition, the processed bone matrices were tested to show excellent cytocompatibility and mechanical stiffness. Thus, we can overcome the limitation of large size and complex shapes of xenograft availability. In addition, the 3D CAD/CAM carving process can provide personalized tailor-designed decellularized bone grafts for the native appearance for maxillofacial reconstruction surgery for oral cancer patients and trauma patients.

Case Report: Histological and Histomorphometrical Results of a 3-D Printed Biphasic Calcium Phosphate Ceramic 7 Years After Insertion in a Human Maxillary Alveolar Ridge

Introduction: Dental implant placement can be challenging when insufficient bone volume is present and bone augmentation procedures are indicated. The purpose was to assess clinically and histologically a specimen of 30%HA-60%β-TCP BCP 3D-printed scaffold, after 7-years.

Case Description: The patient underwent bone regeneration of maxillary buccal plate with 3D-printed biphasic-HA block in 2013. After 7-years, a specimen of the regenerated bone was harvested and processed to perform microCT and histomorphometrical analyses.

Results: The microarchitecture study performed by microCT in the test-biopsy showed that biomaterial volume decreased more than 23% and that newly-formed bone volume represented more than 57% of the overall mineralized tissue. Comparing with unloaded controls or peri-dental bone, Test-sample appeared much more mineralized and bulky. Histological evaluation showed complete integration of the scaffold and signs of particles degradation. The percentage of bone, biomaterials and soft tissues was, respectively, 59.2, 25.6, and 15.2%. Under polarized light microscopy, the biomaterial was surrounded by lamellar bone. These results indicate that, while unloaded jaws mimicked the typical osteoporotic microarchitecture after 1-year without loading, the BCP helped to preserve a correct microarchitecture after 7-years.

Conclusions: BCP 3D-printed scaffolds represent a suitable solution for bone regeneration: they can lead to straightforward and less time-consuming surgery, and to bone preservation.

A novel digital and visualized guided bone regeneration procedure and digital precise bone augmentation: A case series

BACKGROUND

Although the traditional bone augmentation technology can basically meet the clinical needs at present, the effect of bone augmentation in most cases is related to the experience of the operator.

PROPOSE

This study commits to providing a digital solution for precise bone augmentation in the field of oral implantology.

MATERIALS AND METHODS

After collecting the data of patients' intraoral scanning and DICOM (digital imaging and communications in medicine), the implant position is digitally designed, and the alveolar bone is digitally augmented around the ideal implant position. On the premise of ensuring that the thickness of labial bone is 2 mm, and there is sufficient alveolar bone 3 to 4 mm apically from the ideal gingival margin for implant placing, we carry out excessive augmentation of 0.5 and 1 mm on the labial bone and alveolar crest, respectively, to compensate for possible bone resorption after 6 months. After 3D printing the reconstructed alveolar bone model, the titanium mesh is trimmed and preformed on the alveolar bone model. Outcomes are reported in terms of mean values (5%-95% percentile values).

RESULTS

Thirty implant sites have accepted this novel virtually designed alveolar bone augmentation. Before the second-stage surgery, the average vertical bone gain was 2.48 mm (0.29-6.32), the average horizontal bone gain was 4.11 mm (1.19-8.74), the average height of the residual alveolar bone above the implant platform was 1.44 mm (0.59-2.92), the average thickness of the labial bone width at the implant platform was 2.00 mm (0.93-3.64), the average thickness of the labial bone width at 2 mm apically from the implant platform was 2.74 mm (1.40-5.46). The virtual augmentation of each tooth position was 349.41 mm³ (165.70-482.70), while the actual augmentation of each tooth position was 352.94 mm³ (159.24-501.78), the accuracy of the final actual augmentation reached 95.82% (range from 88.53% to 99.15%).

CONCLUSION

This case series suggests that a virtually digital guided bone regeneration (GBR) workflow is precise and controllable. The practicality, safety and effectiveness of this procedure needs to be compared to other bone augmentation procedures in randomized controlled trials.

In vitro and in vivo biocompatibility of calcium-phosphate scaffolds three-dimensional printed by stereolithography for bone regeneration

Stereolithography (SLA) is an interesting manufacturing technology to overcome limitations of commercially available particulated biomaterials dedicated to intra-oral bone regeneration applications. The purpose of this study was to evaluate the in vitro and in vivo biocompatibility and osteoinductive properties of two calcium-phosphate (CaP)-based scaffolds manufactured by SLA three-dimensional (3D) printing. Pellets and macro-porous scaffolds were manufactured in pure hydroxyapatite (HA) and in biphasic CaP (HA:60-TCP:40). Physico-chemical characterization was performed using micro X-ray fluorescence, scanning electron microscopy (SEM), optical interferometry, and microtomography (μCT) analyses. Osteoblast-like MG-63 cells were used to evaluate the biocompatibility of the pellets in vitro with MTS assay and the cell morphology and growth characterized by SEM and DAPI-actin staining showed similar early behavior. For in vivo biocompatibility, newly formed bone and biodegradability of the experimental scaffolds were evaluated in a subperiosteal cranial rat model using μCT and descriptive histology. The histological analysis has not indicated evidences of inflammation but highlighted close contacts between newly formed bone and the experimental biomaterials revealing an excellent scaffold osseointegration. This study emphasizes the relevance of SLA 3D printing of CaP-based biomaterials for intra-oral bone regeneration even if manufacturing accuracy has to be improved and further experiments using biomimetic scaffolds should be conducted.

Hydroxyapatite Block Produced by Sponge Replica Method: Mechanical, Clinical and Histologic Observations

Purpose: The grafting procedure for the anthropic ridges of jaws represents a surgical technique for increasing the bone volume to permit the placement of dental implants for oral rehabilitations. The aim of this study was to evaluate a hydroxyapatite (HA) porous scaffold produced via a sponge replica method for the treatment of maxillary bone defects in a human model. Methods: A total of thirteen patients were treated for sinus lifting in the posterior maxilla for a total of 16 defects treated with cylindrical HA Block. The experimental sites were evaluated by a 3D Cone Beam Computer Tomography scan (CBCT), and the histological analysis was performed after 3 months of healing. Results: After the 3 months healing period, the histological outcome of the investigation showed a high level of biological osteoconduction of the HA. Microscopical evidence of new bone formation was also observed in the central portion of the graft block. The samples were composed of different tissues: 39 ± 1% new bone, 42 ± 3% marrow space, 17 ± 3% residual HA Block and 4.02 ± 2% osteoid tissue were present. The new bone formation in the block was 8 ± 3%. Conclusions: The study findings support that HA porous scaffolds produced by sponge replica were effective for the treatment of maxillary bone defects in humans.

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.

Recent advances in the reconstruction of cranio-maxillofacial defects using computer-aided design/computer-aided manufacturing

With the development of computer-aided design/computer-aided manufacturing (CAD/CAM) technology, it has been possible to reconstruct the cranio-maxillofacial defect with more accurate preoperative planning, precise patient-specific implants (PSIs), and shorter operation times. The manufacturing processes include subtractive manufacturing and additive manufacturing and should be selected in consideration of the material type, available technology, post-processing, accuracy, lead time, properties, and surface quality. Materials such as titanium, polyethylene, polyetheretherketone (PEEK), hydroxyapatite (HA), poly-DL-lactic acid (PDLLA), polylactide-co-glycolide acid (PLGA), and calcium phosphate are used. Design methods for the reconstruction of cranio-maxillofacial defects include the use of a pre-operative model printed with pre-operative data, printing a cutting guide or template after virtual surgery, a model after virtual surgery printed with reconstructed data using a mirror image, and manufacturing PSIs by directly obtaining PSI data after reconstruction using a mirror image. By selecting the appropriate design method, manufacturing process, and implant material according to the case, it is possible to obtain a more accurate surgical procedure, reduced operation time, the prevention of various complications that can occur using the traditional method, and predictive results compared to the traditional method.

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

BACKGROUND

Different surgical procedures have been proposed to achieve horizontal ridge reconstruction of the anterior maxilla; all these procedures, however, require bone replacement materials to be adapted to the bone defect at the time of implantation, resulting in complex and time-consuming procedures. The purpose of this study was to describe how to use a 3D printed hardcopy model of the maxilla to prepare customized milled bone blocks, to be adapted on the bone defect areas using a minimally invasive subperiosteal tunneling technique.

METHODS

Cone beam computed tomography (CBCT) images of the atrophic maxilla of six patients were acquired and modified into 3D reconstruction models. Data were transferred to a 3D printer and solid models were fabricated using autoclavable nylon polyamide. Before the surgery, freeze-dried cortico-cancellous blocks were manually milled and adapted on the 3D printed hardcopy models of the maxillary bone, in order to obtain customized allogeneic bone blocks.

RESULTS

In total, eleven onlay customized allogeneic bone grafts were prepared and implanted in 6 patients, using a minimally invasive subperiosteal tunneling technique. The scaffolds closely matched the shape of the defects: this reduced the operation time and contributed to good healing. The patients did not demonstrate adverse events such as inflammation, dehiscence or flap re-opening during the recovery period; however, one patient experienced scaffold resorption, which was likely caused by uncontrolled motion of the removable provisional prosthesis. Following a 6 month healing period, CBCT was used to assess graft integration, which was followed by insertion of implants into the augmented areas. Prosthetic restorations were placed 4 months later.

CONCLUSIONS

These observations suggest that customized bone allografts can be successfully used for horizontal ridge reconstruction of the anterior maxilla: patients demonstrated reduced morbidity and decreased total surgery time. Further studies on a larger sample of patients, with histologic evaluation and longer follow-up are needed to confirm the present observations.

Platelet-Rich Fibrin (PRF) in Implants Dentistry in Combination with New Bone Regenerative Flapless Technique: Evolution of the Technique and Final Results

Most common techniques for alveolar bone augmentation are guided bone regeneration (GBR) and autologous bone grafting. GBR studies demonstrated long-term reabsorption using heterologous bone graft. A general consensus has been achieved in implant surgery for a minimal amount of 2 mm of healthy bone around the implant. A current height loss of about 3-4 mm will result in proper deeper implant insertion when alveolar bone expansion is not planned because of the dome shape of the alveolar crest. To manage this situation a split crest technique has been proposed for alveolar bone expansion and the implants' insertion in one stage surgery. Platelet-rich fibrin (PRF) is a healing biomaterial with a great potential for bone and soft tissue regeneration without inflammatory reactions, and may be used alone or in combination with bone grafts, promoting hemostasis, bone growth, and maturation.

AIM

The aim of this study was to demonstrate the clinical effectiveness of PRF combined with a new split crest flapless modified technique in 5 patients vs. 5 control patients.

MATERIALS AND METHODS

Ten patients with horizontal alveolar crests deficiency were treated in this study, divided into 2 groups: Group 1 (test) of 5 patients treated by the flapless split crest new procedure; Group 2 (control) of 5 patients treated by traditional technique with deeper insertion of smaller implants without split crest. The follow-up was performed with x-ray orthopantomography and intraoral radiographs at T0 (before surgery), T1 (operation time), T2 (3 months) and T3 (6 months) post-operation.

RESULTS

All cases were successful; there were no problems at surgery and post-operative times. All implants succeeded osteointegration and all patients underwent uneventful prosthetic rehabilitation. Mean height bone loss was 1 mm, measured as bone-implant most coronal contact (Δ-BIC), and occurred at immediate T2 post-operative time (3 months). No alveolar bone height loss was detected at implant insertion time, which was instead identified in the control group because of deeper implant insertion.

CONCLUSION

This modified split crest technique combined with PRF appears to be reliable, safe, and to improve the clinical outcome of patients with horizontal alveolar crests deficiency compared to traditional implanting techniques by avoiding alveolar height-loss related to deeper insertion of smaller implants.

Custom-Made Synthetic Scaffolds for Bone Reconstruction: A Retrospective, Multicenter Clinical Study on 15 Patients

Purpose. To present a computer-assisted-design/computer-assisted-manufacturing (CAD/CAM) technique for the design, fabrication, and clinical application of custom-made synthetic scaffolds, for alveolar ridge augmentation. Methods. The CAD/CAM procedure consisted of (1) virtual planning/design of the custom-made scaffold; (2) milling of the scaffold into the exact size/shape from a preformed synthetic bone block; (3) reconstructive surgery. The main clinical/radiographic outcomes were vertical/horizontal bone gain, any biological complication, and implant survival. Results. Fifteen patients were selected who had been treated with a custom-made synthetic scaffold for ridge augmentation. The scaffolds closely matched the shape of the defects: this reduced the operation time and contributed to good healing. A few patients experienced biological complications, such as pain/swelling (2/15: 13.3%) and exposure of the scaffold (3/15: 20.0%); one of these had infection and complete graft loss. In all other patients, 8 months after reconstruction, a well-integrated newly formed bone was clinically available, and the radiographic evaluation revealed a mean vertical and horizontal bone gain of 2.1 ± 0.9 mm and 3.0 ± 1.0 mm, respectively. Fourteen implants were placed and restored with single crowns. The implant survival rate was 100%. Conclusions. Although positive outcomes have been found with custom-made synthetic scaffolds in alveolar ridge augmentation, further studies are needed to validate this technique.

Biomimetic hydroxyapatite used in the treatment of periodontal intrabony pockets: clinical and radiological analysis

AIM

Hydroxyapatite (PA) has a chemical composition and physical structure very similar to natural bone and therefore it has been considered to be the ideal biomaterial able to ensure a biomimetic scaffold to use in bone tissue engineering. The aim of this study is to clinically test hydroxyapatite used as osteoconductive biomaterial in the treatment of periodontal bone defects. Clinical and radiological evaluations were conducted at 6, 12 and 18 months after the surgery.

MATERIALS AND METHODS

Forty patients with 2- and 3-wall intrabony pockets were enrolled in this study. PPD, CAL, radiographic depth (RD) and angular defects were preoperatively measured. After surgery, patients were re-evaluated every 6 months for 18 months. Statistical analyses were also performed to investigate any differences between preoperative and postoperative measurements.

RESULTS

Paired t-test samples conducted on the data obtained at baseline and 18 months after, showed significant (p<0.01) differences in each measurement performed. The role of preoperative RD was demonstrated to be a significant key factor (p<0.01). A relevant correlation between preoperative PPD and CAL gain was also found.

CONCLUSIONS

Within the limitations of this study, the absence of anatomical variables, except the morphology of the bone defect, emphasizes the importance of the proper surgical approach and the graft material used.

3D-Printed Scaffolds and Biomaterials: Review of Alveolar Bone Augmentation and Periodontal Regeneration Applications

To ensure a successful dental implant therapy, the presence of adequate vertical and horizontal alveolar bone is fundamental. However, an insufficient amount of alveolar ridge in both dimensions is often encountered in dental practice due to the consequences of oral diseases and tooth loss. Although postextraction socket preservation has been adopted to lessen the need for such invasive approaches, it utilizes bone grafting materials, which have limitations that could negatively affect the quality of bone formation. To overcome the drawbacks of routinely employed grafting materials, bone graft substitutes such as 3D scaffolds have been recently investigated in the dental field. In this review, we highlight different biomaterials suitable for 3D scaffold fabrication, with a focus on “3D-printed” ones as bone graft substitutes that might be convenient for various applications related to implant therapy. We also briefly discuss their possible adoption for periodontal regeneration.

Computer-aided design/computer-aided manufacturing of hydroxyapatite scaffolds for bone reconstruction in jawbone atrophy: a systematic review and case report

Background

We reviewed the biological and mechanical properties of porous hydroxyapatite (HA) compared to other synthetic materials. Computer-aided design/computer-aided manufacturing (CAD/CAM) was also evaluated to estimate its efficacy with clinical and radiological assessments.

Method

A systematic search of the electronic literature database of the National Library of Medicine (PubMed-MEDLINE) was performed for articles published in English between January 1985 and September 2013. The inclusion criteria were (1) histological evaluation of the biocompatibility and osteoconductivity of porous HA in vivo and in vitro, (2) evaluation of the mechanical properties of HA in relation to its porosity, (3) comparison of the biological and mechanical properties between several biomaterials, and (4) clinical and radiological evaluation of the precision of CAD/CAM techniques.

Results

HA had excellent osteoconductivity and biocompatibility in vitro and in vivo compared to other biomaterials. HA grafts are suitable for milling and finishing, depending on the design. In computed tomography, porous HA is a more resorbable and more osteoconductive material than dense HA; however, its strength decreases exponentially with an increase in porosity.

Conclusions

Mechanical tests showed that HA scaffolds with pore diameters ranging from 400 to 1200 μm had compressive moduli and strength within the range of the human craniofacial trabecular bone. In conclusion, using CAD/CAM techniques for preparing HA scaffolds may increase graft stability and reduce surgical operating time.

Posterior atrophic mandible rehabilitation with onlay allograft created with CAD-CAM procedure: a case report

AIM

Implant rehabilitation of the atrophic right posterior mandible in a 48-year-old woman using dehydrated homologous bone block, shaped with a computer aided design-computer aided manufacturing (CAD-CAM) system, to avoid harvesting of autologous bone block and to assure a perfect fitting of the block above the alveolar crest.

RESULTS

After 7 months, 6.09, 7.36, and 8.08 mm (mean, 7.18 mm) of total horizontal bone gain was observed at sites 6, 12, and 18 mm posterior to the right mental foramen, respectively.

CONCLUSIONS

The use of a bone block with CAD-CAM system for alveolar ridge augmentation is a valuable alternative to autograft because it reduces time, cost, and complications for the patients. Data from a computerized tomographic scan can be used to shape a precise 3-dimensional homologous bone block using a CAD-CAM system.

Bone Replacement Materials and Techniques Used for Achieving Vertical Alveolar Bone Augmentation

Alveolar bone augmentation in vertical dimension remains the holy grail of periodontal tissue engineering. Successful dental implant placement for restoration of edentulous sites depends on the quality and quantity of alveolar bone available in all spatial dimensions. There are several surgical techniques used alone or in combination with natural or synthetic graft materials to achieve vertical alveolar bone augmentation. While continuously improving surgical techniques combined with the use of auto- or allografts provide the most predictable clinical outcomes, their success often depends on the status of recipient tissues. The morbidity associated with donor sites for auto-grafts makes these techniques less appealing to both patients and clinicians. New developments in material sciences offer a range of synthetic replacements for natural grafts to address the shortcoming of a second surgical site and relatively high resorption rates. This narrative review focuses on existing techniques, natural tissues and synthetic biomaterials commonly used to achieve vertical bone height gain in order to successfully restore edentulous ridges with implant-supported prostheses.

Custom-Made Computer-Aided-Design/Computer-Aided-Manufacturing Biphasic Calcium-Phosphate Scaffold for Augmentation of an Atrophic Mandibular Anterior Ridge

This report documents the clinical, radiographic, and histologic outcome of a custom-made computer-aided-design/computer-aided-manufactured (CAD/CAM) scaffold used for the alveolar ridge augmentation of a severely atrophic anterior mandible. Computed tomographic (CT) images of an atrophic anterior mandible were acquired and modified into a 3-dimensional (3D) reconstruction model; this was transferred to a CAD program, where a custom-made scaffold was designed. CAM software generated a set of tool-paths for the manufacture of the scaffold on a computer-numerical-control milling machine into the exact shape of the 3D design. A custom-made scaffold was milled from a synthetic micromacroporous biphasic calcium phosphate (BCP) block. The scaffold closely matched the shape of the defect: this helped to reduce the time for the surgery and contributed to good healing. One year later, newly formed and well-integrated bone was clinically available, and two implants (AnyRidge, MegaGen, Gyeongbuk, South Korea) were placed. The histologic samples retrieved from the implant sites revealed compact mature bone undergoing remodelling, marrow spaces, and newly formed trabecular bone surrounded by residual BCP particles. This study demonstrates that custom-made scaffolds can be fabricated by combining CT scans and CAD/CAM techniques. Further studies on a larger sample of patients are needed to confirm these results.

Maxillary ridge augmentation with custom-made CAD/CAM scaffolds. A 1-year prospective study on 10 patients

Several procedures have been proposed to achieve maxillary ridge augmentation. These require bone replacement materials to be manually cut, shaped, and formed at the time of implantation, resulting in an expensive and time-consuming process. In the present study, we describe a technique for the design and fabrication of custom-made scaffolds for maxillary ridge augmentation, using three-dimensional computerized tomography (3D CT) and computer-aided design/computer-aided manufacturing (CAD/CAM). CT images of the atrophic maxillary ridge of 10 patients were acquired and modified into 3D reconstruction models. These models were transferred as stereolithographic files to a CAD program, where a virtual 3D reconstruction of the alveolar ridge was generated, producing anatomically shaped, custom-made scaffolds. CAM software generated a set of tool-paths for manufacture by a computer-numerical-control milling machine into the exact shape of the reconstruction, starting from porous hydroxyapatite blocks. The custom-made scaffolds were of satisfactory size, shape, and appearance; they matched the defect area, suited the surgeon's requirements, and were easily implanted during surgery. This helped reduce the time for surgery and contributed to the good healing of the defects.