Clinical and volumetric outcomes after vertical ridge augmentation using computer-aided-design/computer-aided manufacturing (CAD/CAM) customized titanium meshes: a pilot study

Digital Workflow and Guided Surgery in Implant Therapy-Literature Review and Practical Tips to Optimize Precision

The application of digital technology in implant dentistry refines prosthetically-driven treatment planning by integrating virtual facial and intraoral models with cone-beam computed tomography (CBCT) images. This integration enables the development of more personalized treatment plans, ensures precise implant positioning, and strengthens communication between clinicians and patients, thereby reducing potential errors and risks. Computer-aided implant surgery consists of two primary approaches: static-guided surgery, which uses a physical surgical stent to guide the osteotomy based on the preoperatively planned virtual implant position, and dynamic-guided surgery, which employs an optical tracking system with a real-time monitor display for the visualization of implant osteotomy inside the alveolar bone. Each approach offers distinct advantages and poses unique clinical challenges. This paper provides an overview of the current applications and literature on digital treatment planning and computer-aided implant surgery, discussing the advantages and limitations of each approach. Clinical cases are presented to illustrate the digital workflow and highlight key considerations for implementing these methods. Currently, the use of digital workflow in implant dentistry is rising, and it is essential to strike a balance between precision and practicality. The future is promising, with generalized adoption anticipated.

The Role of Digital Technologies in Personalized Craniomaxillofacial Surgical Procedures

Craniomaxillofacial (CMF) surgery addresses complex challenges, balancing aesthetic and functional restoration. Digital technologies, including advanced imaging, virtual surgical planning, computer-aided design, and 3D printing, have revolutionized this field. These tools improve accuracy and optimize processes across all surgical phases, from diagnosis to postoperative evaluation. CMF's unique demands are met through patient-specific solutions that optimize outcomes. Emerging technologies like artificial intelligence, extended reality, robotics, and bioprinting promise to overcome limitations, driving the future of personalized, technology-driven CMF care.

The TACOS Technique: A Stepwise Protocol for Alveolar Ridge Augmentation Using Customized Titanium Mesh

Background: Alveolar ridge resorption following tooth loss poses a significant challenge for successful dental implant placement. In cases of severe atrophy, bone augmentation is required to restore sufficient bone volume. This technical note outlines a detailed, stepwise surgical protocol for horizontal and vertical alveolar ridge augmentation using customized titanium mesh. Materials and Methods: The procedure includes precise mesh fitting, autologous bone grafting, and the application of bioactive agents to promote bone regeneration. Emphasis is placed on the technique's feasibility, predictability, and the critical steps necessary for preventing complications. Results: The use of customized mesh ensures stability and improved bone regeneration outcomes, enabling clinicians to achieve successful implant placement even in severely atrophic ridges. Conclusions: The described protocol has demonstrated predictable results in both clinical and radiographic evaluations, offering an effective solution for complex bone augmentation cases.

Short-term and long-term success and survival rates of implants supporting single-unit and multiunit fixed prostheses: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Whether placing implants to replace each missing tooth or using implant-supported fixed partial dentures provides better outcomes is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to assess the success and survival rates of implants supporting single-unit and multiunit fixed prostheses by using conventional protocols for placement and loading in short- and long-term follow-ups.

MATERIAL AND METHODS

An electronic search was conducted in PubMed, Scopus, and Web of Science for studies published up to March 17, 2022. Comparative studies that reported the success or survival rates of both single-unit and splinted multiunit prostheses were considered for qualitative and quantitative analyses.

RESULTS

A total of 68 publications comprising 11 271 implants were included. Compared with the single prostheses, the splinted multiunit group showed no significant differences in implant success rates in the short-term (risk difference=-0.004; 95% confidence interval (CI)=-0.033 to 0.025; P=.780) and long-term (risk difference=0.003; 95% confidence interval (CI)=-0.029 to 0.034; P=.874) follow-ups. Significant statistical differences were also not found in terms of the survival rates of the 2 groups (short-term risk difference=-0.004; 95% CI=-0.031 to 0.023; P=.779, long-term risk difference=-0.002; 95% CI=-0.029 to 0.025; P=.887).

CONCLUSIONS

Implants supporting single-unit or splinted multiunit prostheses seem to be a predictable treatment in terms of survival and success over short and long periods. Nonetheless, it seems that cantilever and nonsplinted multiunit prostheses should be used with more caution.

Linear bone gain and healing complication rate comparative outcomes following ridge augmentation with custom 3D printed titanium mesh vs Ti-reinforced dPTFE. A randomized clinical trial

AIM

The aim of this randomized clinical trial was to compare the qualitative (linear alveolar ridge changes) and quantitative (healing complications) outcomes after guided bone regeneration (GBR) using a custom-made 3D printed titanium mesh versus titanium reinforced dense PTFE membrane for vertical and horizontal augmentation of deficient alveolar ridges.

Titanium mesh for guided bone regeneration: a systematic review

This systematic review aimed to evaluate results reported in the literature regarding the success rate of the titanium mesh technique for the placement of dental implants. The topic focused on titanium mesh used as a physical barrier for ridge reconstruction in cases of partial or total edentulism. The authors conducted an electronic search of four databases up to October 2023. Six articles fulfilled the inclusion criteria and were analysed. A total of 100 titanium meshes with a minimum of 4.6 months follow up after surgery were studied, and 241 implants were placed. The review shows that the use of titanium mesh is a predictable method for the rehabilitation of complex atrophic sites. Further investigation generating long-term data is needed to confirm these findings.

Artificial intelligence serving pre-surgical digital implant planning: A scoping review

OBJECTIVES

To conduct a scoping review focusing on artificial intelligence (AI) applications in presurgical dental implant planning. Additionally, to assess the automation degree of clinically available pre-surgical implant planning software.

DATA AND SOURCES

A systematic electronic literature search was performed in five databases (PubMed, Embase, Web of Science, Cochrane Library, and Scopus), along with exploring gray literature web-based resources until November 2023. English-language studies on AI-driven tools for digital implant planning were included based on an independent evaluation by two reviewers. An assessment of automation steps in dental implant planning software available on the market up to November 2023 was also performed.

STUDY SELECTION AND RESULTS

From an initial 1,732 studies, 47 met eligibility criteria. Within this subset, 39 studies focused on AI networks for anatomical landmark-based segmentation, creating virtual patients. Eight studies were dedicated to AI networks for virtual implant placement. Additionally, a total of 12 commonly available implant planning software applications were identified and assessed for their level of automation in pre-surgical digital implant workflows. Notably, only six of these featured at least one fully automated step in the planning software, with none possessing a fully automated implant planning protocol.

CONCLUSIONS

AI plays a crucial role in achieving accurate, time-efficient, and consistent segmentation of anatomical landmarks, serving the process of virtual patient creation. Additionally, currently available systems for virtual implant placement demonstrate different degrees of automation. It is important to highlight that, as of now, full automation of this process has not been documented nor scientifically validated.

CLINICAL SIGNIFICANCE

Scientific and clinical validation of AI applications for presurgical dental implant planning is currently scarce. The present review allows the clinician to identify AI-based automation in presurgical dental implant planning and assess the potential underlying scientific validation.

Complications associated with vertical bone augmentation techniques in implant dentistry: A systematic review of clinical studies published in the last ten years

Vertical bone augmentation procedures are increasingly necessary in daily practice. However, it has been reported that vertical ridge augmentation is one of the least predictable techniques in terms of complications. The aim of this systematic review was to evaluate and compare complications in relation to the different procedures used for vertical bone augmentation prior to implant placement. This review was conducted according to PRISMA guidelines. An electronic search was carried out in four databases: The National Library of Medicine (MEDLINE/PubMed); Web of Science; SCOPUS; and Cochrane Central Register of Controlled Trials (CENTRAL). The Newcastle-Ottawa Quality Assessment Scale, the Cochrane Collaboration tool for assessing risk of bias, and The Joanna Briggs Institute Critical Appraisal tool were used to assess the quality of evidence in the studies reviewed. Twenty-five studies with a total of 749 vertically augmented sites were included in the review. Complication rates varied among the different procedures: 51.02% for distraction osteogenesis, 38.01% for bone blocks, and 16.80% for guided bone regeneration. Vertical bone augmentation procedures prior to implant placement are associated with frequent surgical complications and should be approached with caution due to their possible impact on clinical treatment success.

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.

3D printing for bone regeneration: challenges and opportunities for achieving predictability

3D printing offers attractive opportunities for large-volume bone regeneration in the oro-dental and craniofacial regions. This is enabled by the development of CAD-CAM technologies that support the design and manufacturing of anatomically accurate meshes and scaffolds. This review describes the main 3D-printing technologies utilized for the fabrication of these patient-matched devices, and reports on their pre-clinical and clinical performance including the occurrence of complications for vertical bone augmentation and craniofacial applications. Furthermore, the regulatory pathway for approval of these devices is discussed, highlighting the main hurdles and obstacles. Finally, the review elaborates on a variety of strategies for increasing bone regeneration capacity and explores the future of 4D bioprinting and biodegradable metal 3D printing.

Guided bone regeneration in implant dentistry: Basic principle, progress over 35 years, and recent research activities

Bone augmentation procedures are frequent today in implant patients, since an implant should be circumferentially anchored in bone at completion of bone healing to have a good long-term stability. The best documented surgical technique to achieve this goal is guided bone regeneration (GBR) utilizing barrier membranes in combination with bone fillers. This clinical review paper reflects 35 years of development and progress with GBR. In the 1990s, GBR was developed by defining the indications for GBR, examining various barrier membranes, bone grafts, and bone substitutes. Complications were identified and reduced by modifications of the surgical technique. Today, the selection criteria for various surgical approaches are much better understood, in particular, in post-extraction implant placement. In the majority of patients, biodegradable collagen membranes are used, mainly for horizontal bone augmentation, whereas bioinert PTFE membranes are preferred for vertical ridge augmentation. The leading surgeons are using a composite graft with autogenous bone chips to accelerate bone formation, in combination with a low-substitution bone filer to better maintain the augmented bone volume over time. In addition, major efforts have been made since the millenium change to reduce surgical trauma and patient morbidity as much as possible. At the end, some open questions related to GBR are discussed.

A Modified Ridge-Splitting Technique to Restore a Completely Edentulous Maxillary Arch With a Cement-Retained Implant Prosthesis

The present report describes a technique in which the maxillary bone was molded to the desired location using a series of instruments for ridge-splitting procedures. This technique aims to improve bone quality all around the implants at both the crest and apex locations. In some clinical scenarios, insufficient horizontal bone with less than 3 mm prevents implant placement. Thus, ridge splitting is a treatment of choice, and this technique creates bone expansion to form a better receptor site for endosteal implants. A case report is presented involving a completely edentulous 52-year-old male patient presented to the clinic with a horizontal bone defect. The patient complained of having difficulty eating and wants to improve his smile. In this clinical case, a modified ridge-splitting technique was employed, differing from the conventional procedure that uses mallets, chisels, or osteotomes. A lancet and spatula were used for precise ridge splitting, followed by the placement of four endosseous tapered implants-two on each side (Dentis USA, La Palma, USA). Each implant had a diameter of 3.7 mm and a length of 10 mm. These implants were clinically placed in a single visit, with a torque of 30 N/cm² applied to ensure secure fixation. To accommodate the patient's unique maxillary bone anatomy, 25-degree angulated abutments were chosen for the four implants, ensuring a common path of insertion, and optimal angulation for long-term stability and aesthetics. Subsequently, a cemented provisional dental prosthesis restoration was fitted, and the patient reported satisfaction with both function and aesthetics. After a period of five months of osseointegration, the stability of the implants was assessed using a resonance frequency analyzer, yielding positive results. The average resonance frequency values for the maxillary left (canine and premolar) were ISQ 68 and ISQ 71, respectively, while for the maxillary right (lateral incisor and premolar), the values were ISQ 69 and ISQ 73. These readings indicate satisfactory implant stability following the osseointegration process. The postoperative cone-beam computed tomography (CBCT) showed gain to the bone width besides better function and good results concerning the esthetics. This report describes a modified ridge-splitting technique with a predictable and satisfactory outcome that fulfilled the patient's demands. The presented approach overcomes the disadvantages of two-staged implant placement bone grafting procedures and is also a more affordable option for the patient. CBCT evaluation confirmed bone gain with minimal morbidity after the procedure.

Advanced Techniques for Bone Restoration and Immediate Loading after Implant Failure: A Case Report

The objective of this study was to report a clinical case of dental implant failure with significant bone loss that was treated using reconstructive surgical techniques. We present a 58-year-old man with a history of implant surgery and implant failure on the mandible. Data collected using cone beam computed tomography (CBCT) and intraoral scans were exported into Exoplan (exocad GmbH, Darmstadt, Germany), from which a standard tessellation file was obtained. To create a customized mandible mesh design, DentalCAD 3.0 Galway software (exocad GmbH, Darmstadt, Germany) was used. Based on guided bone regeneration, the method involved bone reconstruction and the application of a custom titanium mesh. The bone mix was obtained by combining a xenograft (Cerabone, Bottis biomaterials Gmbh, Zossen, Germany), an allograft (Max Graft, granules Bottis biomaterials Gmbh, Zossen, Germany), and an autograft. The titanium meshes were fixed to the bone using self-drilling screws and covered with a resorbable membrane. Immediately after surgery, an impression was recorded, and the next day, the patient received a milled polymethyl methacrylate interim denture. Based on our case study, the presented custom-made implant can be considered a temporary solution, during which guided bone regeneration is expected to take place.

Three-dimensional volumetric assessment of hard tissue alterations following horizontal guided bone regeneration using a split-thickness flap design: A case series

OBJECTIVES

To analyze morphological, volumetric, and linear hard tissue changes following horizontal ridge augmentation using a three-dimensional radiographic method.

METHODS

As part of a larger ongoing prospective study, 10 lower lateral surgical sites were selected for evaluation. Horizontal ridge deficiencies were treated with guided bone regeneration (GBR) using a split-thickness flap design and a resorbable collagen barrier membrane. Following the segmentation of baseline and 6-month follow-up cone-beam computed tomography scans, volumetric, linear, and morphological hard tissue changes and the efficacy of the augmentation were assessed (expressed by the volume-to-surface ratio).

RESULTS

Volumetric hard tissue gain averaged 605.32 ± 380.68 mm³. An average of 238.48 ± 127.82 mm³ hard tissue loss was also detected at the lingual aspect of the surgical area. Horizontal hard tissue gain averaged 3.00 ± 1.45 mm. Midcrestal vertical hard tissue loss averaged 1.18 ± 0.81 mm. The volume-to-surface ratio averaged 1.19 ± 0.52 mm³/mm². The three-dimensional analysis showed slight lingual or crestal hard tissue resorption in all cases. In certain instances, the greatest extent of hard tissue gain was observed 2-3 mm apical to the initial level of the marginal crest.

CONCLUSIONS

With the applied method, previously unreported aspects of hard tissue changes following horizontal GBR could be examined. Midcrestal bone resorption was demonstrated, most likely caused by increased osteoclast activity following the elevation of the periosteum. The volume-to-surface ratio expressed the efficacy of the procedure independent of the size of the surgical area.

Additive manufacturing technologies in the oral implant clinic: A review of current applications and progress

Additive manufacturing (AM) technologies can enable the direct fabrication of customized physical objects with complex shapes, based on computer-aided design models. This technology is changing the digital manufacturing industry and has become a subject of considerable interest in digital implant dentistry. Personalized dentistry implant treatments for individual patients can be achieved through Additive manufacturing. Herein, we review the applications of Additive manufacturing technologies in oral implantology, including implant surgery, and implant and restoration products, such as surgical guides for implantation, custom titanium meshes for bone augmentation, personalized or non-personalized dental implants, custom trays, implant casts, and implant-support frameworks, among others. In addition, this review also focuses on Additive manufacturing technologies commonly used in oral implantology. Stereolithography, digital light processing, and fused deposition modeling are often used to construct surgical guides and implant casts, whereas direct metal laser sintering, selective laser melting, and electron beam melting can be applied to fabricate dental implants, personalized titanium meshes, and denture frameworks. Moreover, it is sometimes required to combine Additive manufacturing technology with milling and other cutting and finishing techniques to ensure that the product is suitable for its final application.

The effect of bone defect size on the 3D accuracy of alveolar bone augmentation performed with additively manufactured patient-specific titanium mesh

OBJECTIVE

Additively manufactured (3D-printed) titanium meshes have been adopted in the dental field as non-resorbable membranes for guided bone regeneration (GBR) surgery. However, according to previous studies, inaccuracies between planned and created bone volume and contour are common, and many reasons have been speculated to affect its accuracy. The size of the alveolar bone defect can significantly increase patient-specific titanium mesh design and surgical difficulty. Therefore, this study aimed to analyze and investigate the effect of bone defect size on the 3D accuracy of alveolar bone augmentation performed with additively manufactured patient-specific titanium meshes.

METHODS

Twenty 3D-printed patient-specific titanium mesh GBR surgery cases were enrolled, in which 10 cases were minor bone defect/augmentation (the planned bone augmentation surface area is less than or equal to 150 mm² or one tooth missing or two adjacent front-teeth/premolars missing) and another 10 cases were significant bone defect/augmentation (the planned bone augmentation surface area is greater than 150 mm² or missing adjacent teeth are more than two (i.e. ≥ three teeth) or missing adjacent molars are ≥ two teeth). 3D digital reconstruction/superposition technology was employed to investigate the bone augmentation accuracy of 3D-printed patient-specific titanium meshes.

RESULTS

There was no significant difference in the 3D deviation distance of bone augmentation between the minor bone defect/augmentation group and the major one. The contour lines of planned-CAD models in two groups were basically consistent with the contour lines after GBR surgery, and both covered the preoperative contour lines. Moreover, the exposure rate of titanium mesh in the minor bone defect/augmentation group was slightly lower than the major one.

CONCLUSION

It can be concluded that the size of the bone defect has no significant effect on the 3D accuracy of alveolar bone augmentation performed with the additively manufactured patient-specific titanium mesh.

Customized Barrier Membrane (Titanium Alloy, Poly Ether-Ether Ketone and Unsintered Hydroxyapatite/Poly-l-Lactide) for Guided Bone Regeneration

Sufficient bone volume is indispensable to achieve functional and aesthetic results in the fields of oral oncology, trauma, and implantology. Currently, guided bone regeneration (GBR) is widely used in reconstructing the alveolar ridge and repairing bone defects owing to its low technical sensitivity and considerable osteogenic effect. However, traditional barrier membranes such as collagen membranes or commercial titanium mesh cannot meet clinical requirements, such as lack of space-preserving ability, or may lead to more complications. With the development of digitalization and three-dimensional printing technology, the above problems can be addressed by employing customized barrier membranes to achieve space maintenance, precise predictability of bone graft, and optimization of patient-specific strategies. The article reviews the processes and advantages of three-dimensional computer-assisted surgery with GBR in maxillofacial reconstruction and alveolar bone augmentation; the properties of materials used in fabricating customized bone regeneration sheets; the promising bone regeneration potency of customized barrier membranes in clinical applications; and up-to-date achievements. This review aims to present a reference on the clinical aspects and future applications of customized barrier membranes.

Vertical and horizontal ridge augmentation using customized CAD/CAM titanium mesh with versus without resorbable membranes. A randomized clinical trial

Objectives

The aim was to evaluate the role of resorbable membranes applied over customized titanium meshes related to soft tissue healing and bone regeneration after vertical/horizontal bone augmentation.

Materials and Methods

Thirty patients with partial edentulism of the maxilla/mandible, with vertical/horizontal reabsorption of the alveolar bone, and needing implant‐supported restorations, were randomly divided into two groups: Group A was treated using only custom‐made meshes (Mesh‐) and Group B using custom‐made meshes with cross‐linked collagen membranes (Mesh+). Data collection included surgical/technical and healing complications, “pseudo‐periosteum” thickness, bone density, planned bone volume (PBV), regenerated bone volume (RBV), regeneration rate (RR), vertical bone gain (VBG), and implant survival in regenerated areas. Statistical analysis was performed between the two study groups using a significance level of α = .05.

Results

Regarding the healing complications, the noninferiority analysis proved to be inconclusive, despite the better results of group Mesh+ (13%) compared to group Mesh‐ (33%): estimated value −1.13 CI‐95% from −0.44 to 0.17. Superiority approach confirmed the absence of significant differences (p = .39). RBV was 803.27 mm³ and 843.13 mm³, respectively, and higher RR was observed in group Mesh+ (82.3%) compared to Mesh‐ (74.3%), although this value did not reach a statistical significance (p = .44). All 30 patients completed the study, receiving 71 implants; 68 out of them were clinically stable and in function.

Conclusion

The results showed that customized meshes alone do not appear to be inferior to customized meshes covered by cross‐linked collagen membranes in terms of healing complication rates and regeneration rates, although superior results were observed in group Mesh+compared to group Mesh‐ for all variables.

Layered deep learning for automatic mandibular segmentation in cone-beam computed tomography

OBJECTIVE

To develop and validate a layered deep learning algorithm which automatically creates three-dimensional (3D) surface models of the human mandible out of cone-beam computed tomography (CBCT) imaging.

MATERIALS & METHODS

Two convolutional networks using a 3D U-Net architecture were combined and deployed in a cloud-based artificial intelligence (AI) model. The AI model was trained in two phases and iteratively improved to optimize the segmentation result using 160 anonymized full skull CBCT scans of orthognathic surgery patients (70 preoperative scans and 90 postoperative scans). Finally, the final AI model was tested by assessing timing, consistency, and accuracy on a separate testing dataset of 15 pre- and 15 postoperative full skull CBCT scans. The AI model was compared to user refined AI segmentations (RAI) and to semi-automatic segmentation (SA), which is the current clinical standard. The time needed for segmentation was measured in seconds. Intra- and inter-operator consistency were assessed to check if the segmentation protocols delivered reproducible results. The following consistency metrics were used: intersection over union (IoU), dice similarity coefficient (DSC), Hausdorff distance (HD), absolute volume difference and root mean square (RMS) distance. To evaluate the match of the AI and RAI results to those of the SA method, their accuracy was measured using IoU, DSC, HD, absolute volume difference and RMS distance.

RESULTS

On average, SA took 1218.4s. RAI showed a significant drop (p<0.0001) in timing to 456.5s (2.7-fold decrease). The AI method only took 17s (71.3-fold decrease). The average intra-operator IoU for RAI was 99.5% compared to 96.9% for SA. For inter-operator consistency, RAI scored an IoU of 99.6% compared to 94.6% for SA. The AI method was always consistent by default. In both the intra- and inter-operator consistency assessments, RAI outperformed SA on all metrics indicative of better consistency. With SA as the ground truth, AI and RAI scored an IoU of 94.6% and 94.4%, respectively. All accuracy metrics were similar for AI and RAI, meaning that both methods produce 3D models that closely match those produced by SA.

CONCLUSION

A layered 3D U-Net architecture deep learning algorithm, with and without additional user refinements, improves time-efficiency, reduces operator error, and provides excellent accuracy when benchmarked against the clinical standard.

CLINICAL SIGNIFICANCE

Semi-automatic segmentation in CBCT imaging is time-consuming and allows user-induced errors. Layered convolutional neural networks using a 3D U-Net architecture allow direct segmentation of high-resolution CBCT images. This approach creates 3D mandibular models in a more time-efficient and consistent way. It is accurate when benchmarked to semi-automatic segmentation.

Customized-3D zirconia barriers for guided bone regeneration (GBR): clinical and histological findings from a proof-of-concept case series

OBJECTIVES

The aim of this case series was to evaluate, clinically and histologically, customized-3D zirconia barriers manufactured for guided bone regeneration (GBR) procedures.

METHODS

Seven healthy consecutive patients with severe bone atrophy (two of them with a bilateral atrophy) were selected for a GBR procedure with a zirconia barrier. In a 3D software (DentalCad, Exocad GmbH, Germany), a virtual bone graft was designed and a shell was designed covering the graft; a standard tessellation language (.STL) file was obtained and milled (M1, Zirkonzahn, Italy) using a 1200 MPa zirconia (Prettau, Zirkonzahn, Italy). Nine GBR surgeries (8 upper-posterior jaw, 1 lower-posterior jaw) were performed using autogenous bone chips mixed with xenograft (SmartBone, IBI-SA, Switzerland / BioOss, Geistlich, Switzerland) covered with a zirconia barrier, fixed by means of screws. After healing, implant sites were prepared with a trephine bur, collecting a bone biopsy, and dental implants were inserted (Neodent, Straumann Group, Switzerland). Specimens were histologically analyzed.

RESULTS

Eight successful surgeries were recorded; one zirconia barrier got exposed after one month of healing but no signs of infection were present till the barrier was removed. In all cases it was possible to insert implants with no additional bone augmentation procedures. Histological evaluations showed the presence of intense deposition of new bone.

CONCLUSIONS

Within the limitations of the present case series, the tested customized-3D zirconia barriers confirmed good clinical and histological performances, and, even in case of premature exposure, did not show signs of infection. Preliminary results suggest they are effective for GBR procedures. Further research is necessary with a larger sample size.

CLINICAL SIGNIFICANCE

The presented barriers could be a viable alternative to titanium-reinforced polytetrafluoroethylene membranes and customized meshes.

Titanium Meshes in Guided Bone Regeneration: A Systematic Review

The presence of satisfactory bone volume is fundamental for the achievement of osseointegration. This systematic review aims to analyse the use of titanium meshes in guided bone regeneration in terms of bone gain, survival and success rates of implants, and percentages of exposure. An electronic search was conducted Articles were selected from databases in MEDLINE (PubMed), SCOPUS, Scielo, and Cochrane Library databases to identify studies in which bone regeneration was performed through particulate bone and the use of titanium meshes. Twenty-one studies were included in the review. In total, 382 patients, 416 titanium meshes, and 709 implants were evaluated. The average bone gain was 4.3 mm in horizontal width and 4.11 mm in vertical height. The mesh exposure was highly prevalent (28%). The survival rate of 145 simultaneous implants was 99.5%; the survival rate of 507 delayed implants was 99%. The success rate of 105 simultaneous implants was 97%; the success rate of 285 delayed implants was 95.1%. The clinical studies currently available in the literature have shown the predictability of this technique. It has a high risk of soft tissue dehiscence and membrane exposure although the optimal management of membrane exposition permits obtaining a sufficient bone regeneration volume and prevents compromising the final treatment outcome.

Volumetric changes in edentulous alveolar ridge sites utilizing guided bone regeneration and a custom titanium ridge augmentation matrix (CTRAM): a case series study

Background

The purpose of this study was to evaluate the volumetric changes in partially edentulous alveolar ridges augmented with customized titanium ridge augmentation matrices (CTRAM), freeze-dried bone allograft, and a resorbable collagen membrane.

Methods

A pre-surgical cone beam computed tomography (CBCT) scan was obtained for CTRAM design/fabrication and to evaluate pre-surgical ridge dimensions. Ridge augmentation surgery using CTRAM, freeze-dried bone allograft, and a resorbable collagen membrane was performed at each deficient site. Clinical measurements of the area of augmentation were made at the time of CTRAM placement and re-entry, and a 2nd CBCT scan 7 months after graft placement was used for volumetric analysis. Locations of each CTRAM in situ were also compared to their planned positions. Re-entry surgery and implant placement was performed 8 months after CTRAM placement.

Results

Nine subjects were treated with CTRAM and freeze-dried bone allograft. Four out of the nine patients enrolled (44.4%) experienced premature CTRAM exposure during healing, and in two of these cases, CTRAM were removed early. Early exposure did not result in total graft failure in any case. Mean volumetric bone gain was 85.5 ± 30.9% of planned augmentation volume (61.3 ± 33.6% in subjects with premature CTRAM exposure vs. 104.9% for subjects without premature exposure, p = 0.03). Mean horizontal augmentation (measured clinically) was 3.02 mm, and vertical augmentation 2.86 mm. Mean surgical positional deviation of CTRAM from the planned location was 1.09 mm.

Conclusion

The use of CTRAM in conjunction with bone graft and a collagen membrane resulted in vertical and horizontal bone gain suitable for implant placement.

Monitoring Alveolar Ridge Remodelling Post-Extraction Using Sequential Intraoral Scanning over a Period of Four Months

The potential applications of computer-aided design/computer-aided manufacturing (CAD/CAM) and intraoral scanning exceed the delivery of standard prosthodontic interventions. The aim of this study was to clinically present a developed assessment technique, that relies on the use of sequential intraoral scanning, three-dimensional superimposition, and 2D and 3D deviation analyses based on a standardised protocol, as an auxiliary tool in monitoring dimensional changes of residual ridge post-extraction with a follow-up period of four months.