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

Hard tissue stability outside the buccal bone arch contour after guided bone regeneration in the anterior maxilla: A retrospective cohort radiographic study

OBJECTIVES

To radiographically evaluate the stability of the bone substitute augmented outside the buccal bony arch contour in the maxillary esthetic zone.

MATERIALS AND METHODS

Patients who missed a single anterior tooth and received simultaneous GBR in implant surgery were included. The contralateral homonymous area of the implant site was horizontally mirrored as the individual bone arch contour. According to the relative position of the postoperative buccal grafts and bone arch contour at the implant shoulder, 62 patients were allocated into the outside-contour (OC) and inside-contour (IC) groups. Cone-beam computed tomography was performed before surgery, after implant insertion, before re-entry surgery, and at follow-up. The profilometric changes of the buccal bone plate were analyzed via the bone distance to the mirrored bony contour.

RESULTS

At the implant shoulder, the bone distance in the OC group was higher than that in the IC group, with statistically significant differences at re-entry surgery and follow-up. However, the bone grafts outside the bone arch contour were reduced into the contour after remodeling and showed more bone resorption than the IC group. At other vertical levels below the implant shoulder, bony grafting of overcontour 1-2 mm range was favorable to regenerate stable bone plates reaching the individual contour at follow-up.

CONCLUSIONS

The overaugmented bone outside the buccal bone arch contour tended to remodel into the original contour, which indicates that the anterior bone arch contour is worthy of careful observation for deciding buccolingual implant position and bone augmentation width.

Effectiveness of biomechanically stable pergola-like additively manufactured scaffold for extraskeletal vertical bone augmentation

Objective: Extraskeletal vertical bone augmentation in oral implant surgery requires extraosseous regeneration beyond the anatomical contour of the alveolar bone. It is necessary to find a better technical/clinical solution to solve the dilemma of vertical bone augmentation. 3D-printed scaffolds are all oriented to general bone defect repair, but special bone augmentation design still needs improvement.

Methods: This study aimed to develop a structural pergola-like scaffold to be loaded with stem cells from the apical papilla (SCAPs), bone morphogenetic protein 9 (BMP9) and vascular endothelial growth factor (VEGF) to verify its bone augmentation ability even under insufficient blood flow supply. Scaffold biomechanical and fluid flow optimization design by finite element analysis (FEA) and computational fluid dynamics (CFD) was performed on pergola-like additive-manufactured scaffolds with various porosity and pore size distributions. The scaffold geometrical configuration showing better biomechanical and fluid dynamics properties was chosen to co-culture for 2 months in subcutaneously into nude mice, with different SCAPs, BMP9, and (or) VEGF combinations. Finally, the samples were removed for Micro-CT and histological analysis.

Results: Micro-CT and histological analysis of the explanted scaffolds showed new bone formation in the “Scaffold + SCAPs + BMP9” and the “Scaffold + SCAPs + BMP9 + VEGF” groups where the VEGF addition did not significantly improve osteogenesis. No new bone formation was observed either for the “Blank Scaffold” and the “Scaffold + SCAPs + GFP” group. The results of this study indicate that BMP9 can effectively promote the osteogenic differentiation of SCAPs.

Conclusion: The pergola-like scaffold can be used as an effective carrier and support device for new bone regeneration and mineralization in bone tissue engineering, and can play a crucial role in obtaining considerable vertical bone augmentation even under poor blood supply.

A minimally invasive method for titanium mesh fixation with resorbable sutures in guided bone regeneration: A retrospective study

OBJECTIVES

Titanium mesh has become a mainstream choice for guided bone regeneration (GBR) owing to its excellent space maintenance. However, the traditional fixation method using titanium screws impacts surgery efficiency and increases patient trauma. We report a novel method of fixing a titanium mesh using resorbable sutures. We assessed the feasibility of resorbable sutures for fixing a titanium mesh and whether it can serve as a stable, universal, and minimally invasive fixation method for a broader application of titanium meshes.

METHODS

Patients undergoing GBR with a digital titanium mesh fixed using titanium screws (TS group) and resorbable sutures (RS group) were observed at different time points. The stability of the fixation methods was evaluated on parameters such as titanium mesh spatial displacement, bone augmentation, and bone resorption.

RESULTS

A total of 36 patients were included in this study. The exposure rate of the titanium mesh in the TS group was 16.67%, while no exposure was noted in the RS group. There was no significant difference in the parameters of titanium mesh spatial displacement, bone augmentation, and bone resorption between the two groups (p > 0.05).

CONCLUSION

The use of resorbable sutures for fixing a titanium mesh can achieve similar results to traditional fixation using titanium screws. Although this new fixation method can improve the efficiency of the surgery and reduce the risk of complications, the long-term clinical effects require further follow-up investigation.

Marginal bone loss of tissue- or bone-level implants after simultaneous guided bone regeneration in the posterior mandibular region: A retrospective cohort study

PURPOSE

To analyze the marginal bone loss (ΔMBL) of tissue- or bone-level implants after placed with simultaneous guided bone regeneration (GBR).

MATERIALS AND METHODS

A total of 151 patients who received 104 tissue-level or 128 bone-level implants placement with simultaneous GBR in the mandibular posterior region between January 2011 and December 2016 were included in this study. The marginal bone level (MBL) was recorded using the radiographic data obtained at implant placement, second-stage surgery, and the follow-up visit. Generalized estimating equation (GEE) was used to compare the ΔMBL of tissue- and bone-level implants, and the influencing factors of ΔMBL were further analyzed.

RESULTS

At the last follow-up visit, the MBL of tissue-level implants was 0.73 ± 0.86 mm, above the rough-smooth interface, while that of bone-level implants was 0.82 ± 1.05 mm, above the implant platform. The ΔMBL of tissue-level implants was 1.03 mm, which was slightly higher than 0.81 mm of bone-level implants, but there was no significant difference (p > 0.05). No contributing factor associated with ΔMBL was identified by multivariate regression analysis in this study.

CONCLUSION

Within the limits of this retrospective analysis, the ΔMBL of tissue-level implants is similar to that of bone-level implants after placed with simultaneous GBR, and both types of implants can achieve desirable marginal bone stability.

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.

Fully digital versus conventional workflow for horizontal ridge augmentation with intraoral block bone: A randomized controlled clinical trial

OBJECTIVES

To compare the outcome and efficiency of the computer-aided intraoral block bone grafting procedure with those of the conventional technique for the augmentation of horizontal ridge defects.

MATERIALS AND METHODS

A total of 28 patients with single missing tooth in esthetic zone with class IV horizontal alveolar bone defect in need of dental implant restoration were recruited. Computer-aided design of the implant restoration and intraoral block bone grafting was performed for all the participants. The patients were randomly and equally divided into guide and control groups. A fully guided bone harvesting, trimming, and grafting surgery was executed in the guide group. The control group patients underwent surgery without any guide. After 6 months, all the patients underwent implant placement. The primary outcomes were the root mean square estimate (RMSE) values between the outer contours of the actual implanted and planned bone block as well as the RMSE values between the inner surface of the implanted bone block and the original bone surface of the recipient site immediately after surgery. The secondary outcomes were the trimming time of bone block and the surgery-associated complications. The postoperative visual analog scale (VAS) of pain, swelling, and mouth opening difficulty was recorded.

RESULTS

All 28 patients underwent intraoral block bone grafting, followed by the placement of implant after 191.8 ± 19.69 days. The RMSE values between the outer contours of the implanted and planned bone blocks were significantly lower in the guide group (0.37 ± 0.16 mm) as compared to those in the control group (0.72 ± 0.29 mm) (p = 0.0007). The RMSE values between the inner contours of the graft block and original bone at the recipient site were lower in the guide group (0.35 ± 0.15 mm) as compared to those in the control group (0.48 ± 0.17 mm) (p = 0.043). The duration of bone block trimming was shorter in the guide group (401.51 ± 97.60 s) as compared to the control group (602.36 ± 160.57 s) (p = 0.0005). In the control group, two patients received secondary bone grafting, one patient experienced bleeding of donor site and temporary hypoesthesia of the lower lip and chin skin, and one patient developed temporary sensitivity of the adjacent tooth.

CONCLUSIONS

As compared to the conventional procedure, the fully digital workflow in the present study seemed to be a more accuracy and effective protocol for horizontal ridge augmentation with intraoral block bone.

TRIAL REGISTRATION

Chictr.org.cn (ChiCTR2000036390).

Bone regeneration using titanium plate stabilization for the treatment of peri-implant bone defects: A retrospective radiologic pilot study

AIM

To 3-dimensional radiographically assess the effect of titanium plate in guided bone regeneration (GBR) for the treatment of peri-implant ridge defects in esthetic zone.

MATERIAL AND METHODS

Nineteen patients with buccal peri-implant defects in the maxillary esthetic zone were treated with GBR using xenograft, autogenous bone, and collagen membrane. Subjects were divided into two groups: control (conventional GBR, 10 patients with 16 implants) and test (GBR with an adjunctive titanium plate; nine patients with 15 implants). Cone-beam computed tomography (CBCT) images obtained immediately after and 5-7 months following GBR were used to assess buccal crestal bone level (BBL) and buccal bone thickness (BBT) at different implant levels.

RESULTS

Thirty-one implants in 19 patients were evaluated. Titanium plate exposure occurred in three cases (33.33%) of the test group. After 5-7 months, the mean BBL was located 1.48 ± 0.71 mm coronal to the platform in the test group and 0.90 ± 3.03 mm coronal to the platform in the control group (p = 0.03). The mean over all BBT (BBT-M) was 4.16 ± 0.48 mm in the test group and 2.38 ± 0.97 mm in the control group (p < 0.01). More resorption occurred in the control group than in the test group regarding mean BBL (3.00 ± 3.11 mm vs. 0.78 ± 0.79 mm, respectively; p = 0.04), BBT-M change (1.87 ± 1.59 mm vs. 0.56 ± 0.33 mm, respectively; p = 0.02), and percentage change in BBT-M (40.69 ± 24.01% vs. 11.53 ± 5.86%, respectively; p < 0.01).

CONCLUSION

In the short-term, titanium plate-enhanced GBR maintained ridge dimensions better than conventional GBR did.

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.

Hard tissue stability after guided bone regeneration: a comparison between digital titanium mesh and resorbable membrane

Guided bone regeneration (GBR) uses resorbable and non-resorbable membranes as biological barriers. This study compared the differences in hard tissue stability between GBR using evidence-based digital titanium mesh and resorbable collagen membranes during implant placement. A total of 40 patients (65 implant sites) were enrolled and divided into two groups: resorbable membrane and digital titanium mesh groups. The alveolar bone was analyzed at two- and three-dimensional levels using cone-beam computed tomography and by reconstructing and superimposing the hard tissues at four time points: preoperatively, postoperatively, before second-stage surgery, and 1 year after loading. The use of digital titanium mesh showed less alveolar bone resorption in vertical and horizontal directions two-dimensionally before the second-stage surgery and 1 year after loading. Regarding volumetric stability, the percentage of resorption after 6 months of healing with resorbable membrane coverage reached 37.5%. However, it was only 23.4% with titanium mesh. Although postoperative bone volume was greater at all labial sites with resorbable membrane than with digital titanium mesh, after substantial bone resorption within 1 year of loading, the labial bone thickness at the upper part of implants was thinner with resorbable membrane than with digital titanium mesh. Furthermore, digital titanium meshes made according to ideal bone arch contour reduced soft tissue irritation, and the exposure rate was only 10%. Therefore, although both resorbable membrane and digital titanium mesh in GBR were able to successfully reconstruct the bone defect, digital titanium meshes were better at maintaining the hard tissue volume in the osteogenic space.

Innovative Surface Modification Procedures to Achieve Micro/Nano-Graded Ti-Based Biomedical Alloys and Implants

Due to the growing aging population of the world, and as a result of the increasing need for dental implants and prostheses, the use of titanium and its alloys as implant materials has spread rapidly. Although titanium and its alloys are considered the best metallic materials for biomedical applications, the need for innovative technologies is necessary due to the sensitivity of medical applications and to eliminate any potentially harmful reactions, enhancing the implant-to-bone integration and preventing infection. In this regard, the implant’s surface as the substrate for any reaction is of crucial importance, and it is accurately addressed in this review paper. For constructing this review paper, an internet search was performed on the web of science with these keywords: surface modification techniques, titanium implant, biomedical applications, surface functionalization, etc. Numerous recent papers about titanium and its alloys were selected and reviewed, except for the section on forthcoming modern implants, in which extended research was performed. This review paper aimed to briefly introduce the necessary surface characteristics for biomedical applications and the numerous surface treatment techniques. Specific emphasis was given to micro/nano-structured topographies, biocompatibility, osteogenesis, and bactericidal effects. Additionally, gradient, multi-scale, and hierarchical surfaces with multifunctional properties were discussed. Finally, special attention was paid to modern implants and forthcoming surface modification strategies such as four-dimensional printing, metamaterials, and metasurfaces. This review paper, including traditional and novel surface modification strategies, will pave the way toward designing the next generation of more efficient implants.

Titanium mesh for bone augmentation in oral implantology: current application and progress

Guided bone regeneration (GBR) is an effective and simple method for bone augmentation, which is often used to reconstruct the alveolar ridge when the bone defect occurs in the implant area. Titanium mesh has expanded the indications of GBR technology due to its excellent mechanical properties and biocompatibility, so that the GBR technology can be used to repair alveolar ridges with larger bone defects, and can obtain excellent and stable bone augmentation results. Currently, GBR with titanium mesh has various clinical applications, including different clinical procedures. Bone graft materials, titanium mesh covering methods, and titanium mesh fixing methods are also optional. Moreover, the research of GBR with titanium mesh has led to multifarious progresses in digitalization and material modification. This article reviews the properties of titanium mesh and the difference of titanium mesh with other barrier membranes; the current clinical application of titanium mesh in bone augmentation; common complications and management and prevention methods in the application of titanium mesh; and research progress of titanium mesh in digitization and material modification. Hoping to provide a reference for further improvement of titanium mesh in clinical application and related research of titanium mesh.