Application of three-dimensional printing individualized titanium mesh in alveolar bone defects with different Terheyden classifications: A retrospective case series study.

OBJECTIVE: To present the results of guided bone regeneration (GBR) with three-dimensional printing individualized titanium mesh (3D-PITM) applied to alveolar bone defects with different Terheyden classifications and the factors affecting the osteogenic outcome. MATERIALS AND METHODS: Fifty-nine patients, presenting with 61 defect sites, were enrolled between 2018 and 2021. GBR+3D-PITM was obtained with simultaneous or second stage implant placement. The complication rate, the success rate of the bone grafting procedure and the survival rate of the implant were documented. Bone gain, thickness of pseudo-periosteum and peri-implant marginal bone loss (MBL) were measured through digital methods by imaging data (CBCT and X-ray). RESULTS: Out of 61 sites, 20 were exposed (exposure rate: 32.8%). The width, height, and volume bone gain at P3 (mesh removal) were 5.22 ± 3.19 mm, 5.01 ± 2.83 mm, and 588.91 ± 361.23 mm3 , respectively. From P2 (3D-PITM+GBR) to P3 , changes in bone gain were not statistically different in the different Terheyden classifications, the occurrence of exposure (p < .001 for all dimensions) and the different type of pseudo-periosteum (p = .030 for width and p = .002 for height) were significantly correlated with the reduction of bone gain. Terheyden classification of the defect sites was significantly associated with the occurrence of exposure (p = .014) and types of the pseudo-periosteum (p = .015). CONCLUSION: The 3D-PITM can be used in alveolar bone defects with different Terheyden classification, but cases with severe vertical bone defects have a greater chance of the 3D-PITM exposure and the exposure can affect the outcome of bone augmentation.

Predicting the risk of dental implant loss using deep learning.

AIM: To investigate the feasibility of predicting dental implant loss risk with deep learning (DL) based on preoperative cone-beam computed tomography. MATERIALS AND METHODS: Six hundred and three patients who underwent implant surgery (279 high-risk patients who did and 324 low-risk patients who did not experience implant loss within 5 years) between January 2012 and January 2020 were enrolled. Three models, a logistic regression clinical model (CM) based on clinical features, a DL model based on radiography features, and an integrated model (IM) developed by combining CM with DL, were developed to predict the 5-year implant loss risk. The area under the receiver operating characteristic curve (AUC) was used to evaluate the model performance. Time to implant loss was considered for both groups, and Kaplan-Meier curves were created and compared by the log-rank test. RESULTS: The IM exhibited the best performance in predicting implant loss risk (AUC = 0.90, 95% confidence interval [CI] 0.84-0.95), followed by the DL model (AUC = 0.87, 95% CI 0.80-0.92) and the CM (AUC = 0.72, 95% CI 0.63-0.79). CONCLUSIONS: Our study offers preliminary evidence that both the DL model and the IM performed well in predicting implant fate within 5 years and thus may greatly facilitate implant practitioners in assessing preoperative risks.

Development of a rat model for type 2 diabetes mellitus peri-implantitis: A preliminary study.

OBJECTIVE: To develop an in vivo model to simulate the complex internal environment of diabetic peri-implantitis (T2DM-PI) model for a better understanding of peri-implantitis in type 2 diabetic patients. MATERIALS AND METHODS: Maxillary first molars were extracted in Sprague-Dawley (SD) rats, and customized cone-shaped titanium implants were installed in the extraction sites. Thereafter, implants were uncovered and customized abutments were screwed into implants. A high-fat diet and a low-dose injection of streptozotocin were utilized to induce T2DM. Finally, LPS was locally injected in implant sulcus to induce peri-implantitis. RESULTS: In the present study, T2DM-PI model has been successfully established. Imaging analysis revealed that abundant inflammatory cells infiltrated in the soft tissue in T2DM-PI group with concomitant excessive secretion of inflammatory cytokines. Moreover, higher expression of MMP and increased number of osteoclasts led to collagen disintegration and bone resorption in T2DM-PI group. CONCLUSIONS: These results describe a novel rat model which stimulate T2DM-PI in vivo, characterized by overwhelming inflammatory response and bone resorption. This model has a potential to be used for investigation of initiation, progression and interventional therapy of T2DM-PI.

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.

3D-printed customised titanium mesh and bone ring technique for bone augmentation of combined bone defects in the aesthetic zone.

PURPOSE: Complex bone defects with a horizontal and vertical combined deficiency pose a clinical challenge in implant dentistry. This study reports the case of a young female patient who presented with a perforating bone defect in the aesthetic zone. MATERIALS AND METHODS: Based on prosthetically guided bone regeneration, virtual 3D bone augmentation was planned. A 3D printed customised titanium mesh and the autogenous bone ring technique were then utilised simultaneously to achieve a customised bone contour. After 6 months, the titanium mesh was removed and connective tissue grafting was performed. Finally, implants were placed and the provisional and definitive prostheses were delivered following a digital approach. Vertical and horizontal bone gain, new bone density, pseudo-periosteum type and marginal bone loss were measured. Planned bone volume, regenerated bone volume and regeneration rate were analysed. RESULTS: Staged tooth shortening led to a coronal increase in keratinised mucosa. The customised titanium mesh and bone ring technique yielded 14.27 mm vertical bone gain and 12.9 mm horizontal bone gain in the perforating area. When the titanium mesh was removed, the reopening surgery showed a Type 1 pseudo-periosteum (none or < 1 mm), and CBCT scans revealed a new bone density of ~550 HU. With a planned bone volume of 1063.55 mm3, the regenerated bone volume was 969.29 mm3, indicating a regeneration rate of 91.14%. The 1-year follow-up after definitive restoration revealed no complications except for 0.55 to 0.60 mm marginal bone loss. CONCLUSION: Combined application of customised titanium mesh and an autogenous bone ring block shows promising potential to achieve prosthetically guided bone regeneration for complex bone defects in the aesthetic zone.

Virtual sketching-based dental anatomy module improves learners' abilities to use computer-aided design to create dental restorations and prostheses.

Dental anatomy education for dental technology students should be developed in alignment with digital dental laboratory practices. We hypothesized that a virtually assisted sketching-based dental anatomy teaching module could improve students' acquisition of skills essential for digital restoration design. The second-year dental technology curriculum included a novel virtual technology-assisted sketching-based module for dental anatomy education. Pre- and post-course assessments evaluated students' skill sets and knowledge bases. Computer-aided design (CAD) scores were analyzed after one year to assess how the skills students developed through this module impacted their subsequent CAD performance. Participants who undertook the dental sketching-based teaching module demonstrated significantly improved theoretical knowledge of dental anatomy, dental aesthetic perception, and spatial reasoning skills. A partial least squares structural equation model indicated that the positive effects of this module on subsequent CAD performance were indirectly mediated by dental aesthetic perception, spatial reasoning, and practice time. A virtually assisted sketching-based dental anatomy teaching module significantly improved students' acquisition of skills and knowledge and positively mediated dental technology students' CAD performance.

Facile and Programmable Capillary-Induced Assembly of Prototissues via Hanging Drop Arrays.

An important goal for bottom-up synthetic biology is to construct tissue-like structures from artificial cells. The key is the ability to control the assembly of the individual artificial cells. Unlike most methods resorting to external fields or sophisticated devices, inspired by the hanging drop method used for culturing spheroids of biological cells, we employ a capillary-driven approach to assemble giant unilamellar vesicles (GUVs)-based protocells into colonized prototissue arrays by means of a coverslip with patterned wettability. By spatially confining and controllably merging a mixed population of lipid-coated double-emulsion droplets that hang on a water/oil interface, an array of synthetic tissue-like constructs can be obtained. Each prototissue module in the array comprises multiple tightly packed droplet compartments where interfacial lipid bilayers are self-assembled at the interfaces both between two neighboring droplets and between the droplet and the external aqueous environment. The number, shape, and composition of the interconnected droplet compartments can be precisely controlled. Each prototissue module functions as a processer, in which fast signal transports of molecules via cell-cell and cell-environment communications have been demonstrated by molecular diffusions and cascade enzyme reactions, exhibiting the ability to be used as biochemical sensing and microreactor arrays. Our work provides a simple yet scalable and programmable method to form arrays of prototissues for synthetic biology, tissue engineering, and high-throughput assays.

Evaluation of surgical placement accuracy of customized CAD/CAM titanium mesh using screws-position-guided template: A retrospective comparative study.

BACKGROUND: Customized computer-aided-design/computer-aided-manufacturing (CAD/CAM) titanium meshes have been adopted for alveolar bone augmentation. But the inaccuracies between planned and created bone volume/contour are quite common, and the surgical placement of the customized mesh was considered as the first critical factor. However, the evaluation of surgical placement accuracy of customized mesh is currently lacking. PURPOSE: The aim of this study was to evaluate the accuracy of the surgical placement of customized meshes. METHODS: A total of 30 cases, 20 without the screws-position-guided template and 10 with the screws-position-guided template, were included in this study. The cone beam CT (CBCT) data sets of pre- and postoperative were converted into 3D models and digitally aligned. Then the actual placement of customized mesh and retainer titanium screws was compared to the virtual one to assess the surgical placement accuracy of customized mesh. At least 6 months after surgery, a new CBCT was taken and converted into 3D models. Planned bone volume, created bone volume, vertical bone augmentation, healing complications rate, pseudo-periosteum rate, exposure rate, and infection rate were all evaluated. RESULTS: The 3D digital reconstruction/registration analysis showed that the average difference between actual placement and planned one of customized mesh in positive and negative directions was 2.69 ± 0.70 mm and -1.41 ± 0.90 mm, respectively, without the screws-position-guided template. And the mean difference values between the actual and planned placement of the screws on the X and Y axes were 0.74 ± 0.85 mm and 0.89 ± 0.84 mm. In contrast, with the screws-position-guided template, the results were 2.38 ± 0.69 mm and -1.30 ± 1.13 mm. Accordingly, the mean difference values of screws were 0.76 ± 0.84 mm and 0.94 ± 0.72 mm. There was no statistical difference between the two groups, and the noninferiority of the control group compared to the test group was also confirmed by the comparative analysis. CONCLUSION: It can be concluded that there is a certain deviation between the planned surgical placement and actual one of customized mesh, and using screws-position-guided template is of limited help for its accurate placement. Further research is needed to achieve precise surgical placement of the customized mesh to achieve precise alveolar bone augmentation.

Portable Handheld "SkinPen" Loaded with Biomaterial Ink for In Situ Wound Healing.

In situ bioprinting has emerged as an attractive tool for directly depositing therapy ink at the defective area to adapt to the irregular wound shape. However, traditional bioprinting exhibits an obvious limitation in terms of an unsatisfactory bioadhesive effect. Here, a portable handheld bioprinter loaded with biomaterial ink is designed and named "SkinPen". Gelatin methacrylate (GelMA) and Cu-containing bioactive glass nanoparticles (Cu-BGn) serve as the main components to form the hydrogel ink, which displays excellent biocompatibility and antibacterial and angiogenic properties. More importantly, by introducing ultrasound and ultraviolet in a sequential programmed manner, the SkinPen achieves in situ instant gelation and amplified (more than threefold) bioadhesive shear strength. It is suggested that ultrasound-induced cavitation and the resulting topological entanglement contribute to the enhanced bioadhesive performance together. Combining the ultrasound-enhanced bioadhesion with the curative role of the hydrogel, the SkinPen shows a satisfactory wound-healing effect in diabetic rats. Given the detachable property of the SkinPen, the whole device can be put in a first-aid kit. Therefore, the application scenarios can be expanded to many kinds of accidents. Overall, this work presents a portable handheld SkinPen that might provide a facile but effective approach for clinical wound management.

Assessment of Customized Alveolar Bone Augmentation Using Titanium Scaffolds vs Polyetheretherketone (PEEK) Scaffolds: A Comparative Study Based on 3D Printing Technology.

Customized alveolar bone augmentation provides sufficient and precisely regenerated bone tissue for subsequent dental implant placement. Although some clinical cases have confirmed the successful use of the patient-specific polyetheretherketone (PEEK) scaffolds, the biomechanical property and osteogenic performance of the patient-specific PEEK scaffolds remain unclear. The objectives of this study were (1) to evaluate the space maintenance capacity and osteogenic performance of the patient-specific PEEK scaffolds for customized alveolar bone augmentation and (2) to compare the biomechanical properties of three-dimensionally printed titanium scaffolds and PEEK scaffolds. Both titanium scaffolds and PEEK scaffolds were designed and manufactured via additive manufacturing technology combined with computer-aided design (CAD). In three-point bending tests, the bending strength of the PEEK scaffold was about 1/3 that of the titanium scaffold. Accordingly, the equivalent strain value of the internal bone graft beneath the PEEK scaffold was about 3 times that beneath the titanium scaffold in finite element analysis, but the maximum deformations of both scaffolds were less than 0.05 mm. Meanwhile, in in vivo experiments, it is demonstrated that both scaffolds have similar space maintenance capacity and bone ingrowth efficiency. In conclusion, patient-specific PEEK scaffolds showed significantly lower biomechanical strength but comparable space maintenance and osteogenic properties to the titanium counterpart. Compared with traditional guided bone regeneration (GBR) surgery, both patient-specific PEEK and titanium scaffolds can achieve excellent osteogenic space maintenance ability. This study provides a preliminary basis for the clinical translation of the nonmetallic barrier membrane in customized alveolar bone augmentation.

Research on the dimensional accuracy of customized bone augmentation combined with 3D-printing individualized titanium mesh: A retrospective case series study.

BACKGROUND: Few studies have focused on the dimensional accuracy of customized bone grafting by means of guided bone regeneration (GBR) with 3D-Printed Individual Titanium Mesh (3D-PITM). PURPOSE: Digital technologies were applied to evaluate the dimensional accuracy of customized bone augmentation with 3D-PITM with a two-stage technique. MATERIALS AND METHODS: Sixteen patients were included in this study. The CBCT data of post-GBR (immediate post-GBR) and post-implantation (immediate post-implant placement) were 3D reconstructed and compared with the pre-surgical planned bone augmentation. The dimensional differences were evaluated by superimposition using the Materialize 3-matic software. RESULTS: The superimposition analysis showed that the maximum deviations of contour between were 3.4 mm, and the average differences of the augmentation contour were 0.5 ± 0.4 and 0.6 ± 0.5 mm respectively. The planned volume of bone regeneration was approximately equal to the amount of regenerated bone present 6 to 9 months after the surgical procedure. On average, the vertical gain in bone height was about 0.5 mm less than planned. And, the horizontal bone gain on the straight buccal of the dental implants and 2 to 4 mm apical of the platform fell also about a 0.5 mm short on average. Statistically significant differences were observed between the augmented volume of virtual and post-GBR, and the horizontal bone gain of post-implantation on the level of 4 mm apical to the implant platform (P < .05). CONCLUSIONS: The dimensional accuracy of customized bone augmentation with the 3D-PITM approach needs further improvement and compared to other surgical approaches of bone augmentation.

Influence of the amount of intermetallics on the degradation of Mg-Nd alloys under physiological conditions.

The influence of amount of intermetallics on the degradation of as-extruded Mg-Nd alloys with different contents of Nd was investigated via immersion testing in DMEM+10% FBS under cell culture conditions and subsequent microstructural characterizations. It is found that the presence of intermetallic particles Mg41Nd5 affects the corrosion of Mg-Nd alloys in two conflicting ways. One is their negative role that their existence enhances the micro-galvanic corrosion. Another is their positive role. Their existence favours the formation of a continuous and compact corrosion layer. At the early stage of immersion, their negative role predominated. The degradation rate of Mg-Nd alloys monotonously increases with increasing the amount of intermetallics. Mg-5Nd alloy with maximum amount of intermetallics suffered from the most severe corrosion. With the immersion proceeding (≥7 days), then the positive role of these intermetallic particles Mg41Nd5 could not be neglected. Owing to the interaction between their positive and negative roles, at the later stage of immersion the corrosion rate of Mg-Nd alloys first increases with increasing the content of Nd, then reaches to the maximum at 2 wt. % Nd. With a further increase of Nd content, a decrease in corrosion rate occurs. The main corrosion products on the surfaces of Mg-Nd alloys include carbonates, calcium-phosphate, neodymium oxide and/or neodymium hydroxide. They are amorphous at the early stage of immersion. With the immersion proceeding, they are transformed to crystalline. The existence of undegradable Mg41Nd5 particles in the corrosion layer can enhance the crystallization of such amorphous corrosion products.

Effects of immediately static loading on osteointegration and osteogenesis around 3D-printed porous implant: A histological and biomechanical study.

The 3D-printed porous implant is capable of achieving favorable osteointegration and osteogenesis in the absence of mechanical stimulation during the early healing period. The purpose of this study is to evaluate the impact of immediately static loading on bone osteointegration and osteogenesis around the 3D-printed porous implant. Thirty porous implants with optimal configuration were installed bilaterally into femurs of 15 rabbits. The Load group on the left side was applied the maximal initial load of 10 N offered by a diminutive and built-in loading device and the Non-load group was on the contralateral side. At 2, 4, and 8 weeks post-operatively, the explants were harvested for push-out test to measure the biological fixation strength. The quantity and quality of new bone were evaluated by the means of histological examination, Micro-CT and bone density analysis. Moreover, the animal data were integrated into finite element models to assess the biomechanics of peri-implant bone. The results indicated that the quantity, quality and biomechanical properties of the new bone increased and optimized along with the healing time. It also demonstrated that the immediately static loading increased the volume of new bone with inferior quality in 2 weeks after implantation and the adverse influence emerged gradually as time extended. Moreover, finite element results demonstrated that the early structures of new bone around porous implant were not suitable for functional loading. This study indicated the mineralization modes of distance osteogenesis and contact osteogenesis around the porous implant. Accordingly, the delay and progressive loading protocol was recommended.

Effect of Porous Microstructures on the Biomechanical Characteristics of a Root Analogue Implant: An Animal Study and a Finite Element Analysis.

BACKGROUND: Full ceramic or metal custom-made root analogue implants (RAIs) are made by replicating the natural tooth geometry. However, it may lead to the stress shielding of the surrounding bone, and an RAI is unable to easily achieve primary stability. Therefore, to improve primary stability and reduce stress shielding, RAI porous structures are proposed. The purpose of this study was to evaluate the effect of porous microstructures on the biomechanical characteristics of the custom-made RAI. METHODS: Porous and bulk titanium cylinders and porous RAI and conventional implants for in vivo tests were fabricated using a selective laser melting (SLM) technology. The elastic modulus and the compressive strength of porous titanium cylinders were evaluated. These samples were then implanted into rabbit femurs (cylinders) and beagle dog mandibles (RAI and conventional implants). A simplified three-dimensional geometry of the anterior maxilla of a patient was constructed. Then, based on the extracted standard template library (STL) data, five different RAI models were constructed: (A) smooth surface, (B) pit surface, (C) bulb surface, (D) threaded surface, and (E) porous surface. A conventional implant model was also constructed. A static load of 100 N was applied to the crown in the multivectoral direction. RESULTS: The results of the in vivo experiment confirmed that the porous structure decreased the elastic modulus of Ti6Al4V. Additionally, the implantation of the porous custom-made RAIs resulted in increased new bone ingrowth and decreased bone resorption compared to conventional implants. Moreover, the 3D finite element analysis suggested that the bone surrounding porous custom-made RAIs was subjected to a more uniform stress distribution, and the strain values of the surrounding bone were more conducive to bone formation. CONCLUSION: Based on these findings, a custom-made RAI with a porous surface accelerates bone formation and might reduce the stress-shielding effect.

Comparison of in-situ bone ring technique and tent-pole technique for horizontally deficient alveolar ridge in the anterior maxilla.

BACKGROUND: Limited studies focused on the bone profile maintenance at the alveolar ridge crest applying horizontal bone augmentation. PURPOSE: A novel approach named as "in-situ bone ring technique" was introduced to be compared with tent-pole technique to evaluate their horizontal bone gain, resorption, and postoperative perception. MATERIALS AND METHODS: A total of 30 patients were included in this retrospective cohort study. All patients required horizontal bone augmentation at anterior site. Accordingly, quantitative and qualitative analyses were conduct radiographically and histologically between in-situ bone ring (ring group) and tent-pole technique (tent group). Moreover, the visual analog scale (VAS) was introduced to assess the patients' perception toward both treatments. RESULTS: Cone-beam computed tomography results showed great significant difference regarding horizontal bone width at 0 mm and 3 mm from alveolar ridge crest between two groups (P < .05). On the basis of histological outcomes, delightful bony fusion was shown 6-month postoperatively in ring group. The VAS ratings for pain and swelling reflected similar results between two groups. CONCLUSIONS: In-situ bone ring technique evidently increased and maintained horizontal bone mass at the alveolar ridge crest compared to tent-pole technique, which might be favorable for implant rehabilitation in anterior area. Meanwhile, no further discomfort was caused according to VAS scoring between two groups.

Biomechanical comparison of implant inclinations and load times with the all-on-4 treatment concept: a three-dimensional finite element analysis.

The purpose of this study was to compare the effects of implant inclinations and load times on stress distributions in the peri-implant bone based on immediate- and delayed-loading models. Four 3D FEA models with different inclination angle of the posterior implants (0°, 15°, 30°, 45°) were constructed. A static load of 150 N in the multivectoral direction was applied unilaterally to the cantilever region. The stress distributions in the peri-implant bone were evaluated before and after osseointegration. The principal tensile stress (σmax), mean principal tensile stress (σmax), principal compressive stress (σmin) and mean principal compressive stress (σmin) of the bone and micromotion at the contact interface between the bone and implants were calculated. In all the models, peak principal stresses occurred in the bone surrounding the left tilted implant. The highest σmax and σmin were all observed in the 0° model for both immediate- and delayed-loading models. And the 0° and 15° models showed higher σmax and σmin values. The 0°models showed the largest micromotion. The observed stress distribution was better in the 30° and 45° models than in the 0° and 15° models.

Effects of Programmed Local Delivery from a Micro/Nano-Hierarchical Surface on Titanium Implant on Infection Clearance and Osteogenic Induction in an Infected Bone Defect.

The two major causes for implant failure are postoperative infection and poor osteogenesis. Initial period of osteointegration is regulated by immunocytes and osteogenic-related cells resulting in inflammatory response and tissue healing. The healing phase can be influenced by various environmental factors and biological cascade effect. To synthetically orchestrate bone-promoting factors on biomaterial surface, built is a dual delivery system coated on a titanium surface (abbreviated as AH-Sr-AgNPs). The results show that this programmed delivery system can release Ag+ and Sr2+ in a temporal-spatial manner to clear pathogens and activate preosteoblast differentiation partially through manipulating the polarization of macrophages. Both in vitro and in vivo assays show that AH-Sr-AgNPs-modified surface renders a microenvironment adverse for bacterial survival and favorable for macrophage polarization (M2), which further promotes the differentiation of preosteoblasts. Infected New Zealand rabbit femoral metaphysis defect model is used to confirm the osteogenic property of AH-Sr-AgNPs implants through micro-CT, histological, and histomorphometric analyses. These findings demonstrate that the programmed surface with dual delivery of Sr2+ and Ag+ has the potential of achieving an enhanced osteogenic outcome through favorable immunoregulation.

Promotion of Osseointegration Using Protamine/Alginate/Bone Morphogenic Protein 2 Biofunctionalized Composite Coating on Nanopolymorphic Titanium Surfaces.

A bioactive paradigm is required to promote osseointegration of implant materials. Here, a protamine/alginate/bone morphogenic protein 2 (BMP2) biofunctionalized composite coating was created on nanopolymorphic titanium (Ti) surfaces to promote the osseointegration of Ti implants. Alkali and heat (AH) treatment was used to make porous Ti implants (TiAH) with a superhydrophilic and negatively charged surface, which facilitates the adsorption of a positively charged protamine/alginate/protamine (TiAH-Pro/Alg/Pro) coating. Biofunctionalization of the substrate was achieved via further immobilization of exogenous BMP2 (TiAH-Pro/Alg/Pro-BMP2). The results indicated the successful deposition of Pro/Alg/Pro coatings onto porous TiAH substrates. In addition, the initial burst release of the adsorbed protein was effectively dampened by the TiAH-Pro/Alg/Pro coating, allowing uniform protein distribution and sustained biomolecule release. In comparison with the pristine Ti, the three modified substrates showed good cytocompatibility and promoted cell adhesion in the initial period. The adherent cells on the TiAH-Pro/Alg/Pro surface and TiAH-Pro/Alg/Pro-BMP2 substrate exhibited distinct shapes compared to those on the pristine Ti and TiAH surfaces. Moreover, TiAH-Pro/Alg/Pro-BMP2 significantly improved the in vitro osteogenic differentiation of MC3T3-E1 cells and enhanced the osseointegration in the in vivo rat model. Such facilitative effects may be achieved by activating integrins and the BMP/Smad signaling pathway. This study highlights the potential of combining inorganic with organic surface modifications for accelerating the osseointegration of implant materials.

Biomechanical Effects of Various Bone-Implant Interfaces on the Stability of Orthodontic Miniscrews: A Finite Element Study.

INTRODUCTION: Osseointegration is required for prosthetic implant, but the various bone-implant interfaces of orthodontic miniscrews would be a great interest for the orthodontist. There is no clear consensus regarding the minimum amount of bone-implant osseointegration required for a stable miniscrew. The objective of this study was to investigate the influence of different bone-implant interfaces on the miniscrew and its surrounding tissue. METHODS: Using finite element analysis, an advanced approach representing the bone-implant interface is adopted herein, and different degrees of bone-implant osseointegration were implemented in the FE models. A total of 26 different FE analyses were performed. The stress/strain patterns were calculated and compared, and the displacement of miniscrews was also evaluated. RESULTS: The stress/strain distributions are changing with the various bone-implant interfaces. In the scenario of 0% osseointegration, a rather homogeneous distribution was predicted. After 15% osseointegration, the stress/strains were gradually concentrated on the cortical bone region. The miniscrew experienced the largest displacement under the no osseointegra condition. The maximum displacement decreases sharply from 0% to 3% and tends to become stable. CONCLUSION: From a biomechanical perspective, it can be suggested that orthodontic loading could be applied on miniscrews after about 15% osseointegration without any loss of stability.

Biomechanical evaluation of the natural abutment teeth in combined tooth-implant-supported telescopic prostheses: a three-dimensional finite element analysis.

Telescopic overdentures supported by the combination of natural teeth and implants have been thought a valuable treatment for the severely compromised partially edentulous patients. But the combination of teeth and implants involves highly complex biomechanical problems. This study is to evaluate biomechanical behaviors of the natural abutment teeth with the treatment of combined tooth-implant supported telescopic crown prostheses in mandible through 3D FEA. According to this study, the prosthetic option supported by a combination of teeth and implants and retained by double crowns could protect teeth and their periodontal support tissues acting as a rigid splint, and may be a valuable treatment option for partially edentulous patients with severely reduced remaining teeth in mandible.