Commercial Dental Implants Research Articles

Calculation of Dose Perturbation in Radiotherapy of Head and Neck Tumors Due to the Presence of Dental Implants: A Monte Carlo Study

Purpose: The presence of a dental implant across the irradiation beam has the potential to perturb the dose distribution. In this study, the effect of different commercial dental implants on dose distribution was investigated in electron beam therapy. Materials and Methods: The Varian 2100 C/D linear accelerator (Linac) head was modeled precisely with proper components for electron mode (6 and 9 MeV) by MCNPX 2.6.1 and was benchmarked according to the International Atomic Energy Agency (IAEA) protocol, TRS -398. Dose distribution was calculated for Six different implant materials, including Titanium, Titanium alloy, Zirconia (Y-TZP), Zirconium oxide, Alumina, and PolyetherEtherKetone (PEEK), and for Four different scenarios. Results: The highest and lowest increasing doses occurred for Y-TZP (114.44% and 108.69% for 6 and 9 MeV, respectively) and PEEK (104.85% and 98.84% for 6 and 9 MeV, respectively) directly in front of the implant, respectively. By removing an implant from the jaw, an increasing dose was not seen, but an increasing dose occurred behind its depths in the bone region (31.81 %). Conclusion: The amount of dose perturbation due to the dental implant's presence depends on the beam energy, mass density, and atomic numbers of implants. Maximum and minimum increased doses were estimated for Y-TZP and PEEK implants, respectively. Considering the correction factors due to the presence of high density and atomic number dental implants are essential to estimate the accurate dose delivery in radiotherapy with electron beams.

Evaluation of anti-inflammatory properties on the surface of dental implants depending on the type of processing (Part 1)

The aim. To study of the anti-inflammatory properties of the surface of commercial dental implants with different processing methods using the example of the course of the first stage of implantation. Materials and methods. Dental implants made of titanium with 3D Active and Xpeed surface treatment were used. The surface microstructure and biocompatibility of the samples, surface corrosion, elemental analysis of the surface was studied. The assessment of the severity of peri-implantitis and mucositis based on the depth of the peri-implant pocket and bleeding during probing, determination of the coefficient of stability of implants (KSI) is given. Median test (χ2), Kruskel–Wallis test (H), univariate variance analysis (F) were used for multiple comparison of samples. The difference in parameters was considered statistically significant at the p ≤ 0.05 level. Results. The surfaces of 3D Active implants are monolithic with rounded pores in the form of wells of different diameters and depths; the upper layer of the Xpeed sample consists of closely adjacent to each other fragments of a rectangular or polygonal shape, in the form of tiles, leaving rectangular faces on the outside. On the surface of the 3D Active samples, in addition to oxygen and carbon, there was phosphorus – 5.04 wt%, as well as S, Ca, Na, Zr, Zn which weight percentage did not exceed 1 wt%. A significant difference in the elemental composition of Xpeed implants was the presence of chlorine 0.07 wt% and 0.93 wt%, silicon – 0.10 wt% and 0.14 wt%, aluminum 0.06 wt% and 0.23 wt%, respectively, with the latter has a significant advantage in these elements. Xpeed had an insignificant weight percentage of iron in its composition – 0.12 wt%. The assessment of cell adhesion to the surface of the samples on the first day of incubation demonstrated that the samples with the Xpeed and 3D Active surfaces did not have a statistically significant difference between them. Also, on the 7th day of incubation, the level of reduction of resazurin in Xpeed was lower, no significant difference was observed (p > 0.05). The clinical signs of bone tissue resorption were identified in 36.4 % of 3D Active implants and 60.0 % of Xpeed implants (p = 0.3); inflammation of the mucous membrane – in the areas of installation of 54.5 % of 3D Active implants. No signs of mucositis were detected around the Xpeed implants (p = 0.23). 9.1 % of 3D Active implants were “lost”; no cases of loss of Xpeed implants have been identified. The KSI of 3D Active – 64.0 ± 5.9 units, Xpeed – 65.1 ± 3.7 units. Conclusions. According to KSI indicators, titanium implants with Xpeed coating (65.1 ± 3.7 units) and 3D Active (64.0 ± 5.9 units) showed the same capabilities. Bone tissue resorption without signs of inflammation is more common around Xpeed-coated implants than 3D Active-coated implants. Clinical signs of inflammation are more frequent and more severe around implants with a 3D Active coating, which affected both the severity of the course of the first stage of implantation and its results. Xpeed-coated implants are more reliable than 3D Active: loss among 3D Active implants was 9.1 %, Xpeed – 0.0 %.

The effect of contaminating media on the static and dynamic mechanical resilience of dental implant abutments' screws: In vitro study.

This in vitro study aims to biomechanically evaluate the influence of medium contamination for example, saliva, blood, chlorhexidine (liquid and gel), and fluoride mouthwash on the biomechanical behavior of implant abutments' screws under static and dynamic loading. Forty five Ti6Al4V commercial dental implants and abutments were tested in this study. Two main mechanical tests were carried out in the selected media. The first, static, aimed to evaluate the torque loss after the first tightening. The second, dynamic, involved a random cyclic load range between 0 and 200 N to evaluate torque loss due to mastication. In addition, metallographic longitudinal and cross-sections of the abutment-implant apparatus were examined to evaluate the abutment screw-abutment-implant interface. The static torque test showed that irrespective of the media, no statistical difference in static torque loss was found prior to dynamic loading. For the dynamic tests, torque-angle evolution analysis during tightening to 30 Ncm and after the spectrum loading, showed the same global mechanical behavior for all media, but the statistical analysis indicated a difference between the groups in reverse torque values (RTV) and in the torque loss due to dynamic loading. The medium groups CHX, CHX-gel, and Fluoride mouthwash, showed a meaningful torque loss due to loading, but the medium groups, control (no medium), blood and saliva showed an opposite trend and required a higher torque to open the abutment screws. The microstructural analysis revealed clear signs of cold-welding/galling, post-dynamic loading in these latter groups. The presence of lubrication/contamination media (CHX mouthwash/CHX-gel/Fluoride mouthwash) reduces the preload generated due to tightening but prevents damage due to galling. The observed reduction of RTV clearly emphasizes the need for frequent abutment screw retightening for implant-supported prosthetic long-term stability.

Agglomeration effect on biomechanical performance of CNT-reinforced dental implant using micromechanics-based approach

Dental implants have long played an important role in restoring lost teeth, but there are still concerns about their durability and long-term success. Commercial dental implants have traditionally been made of metallic and ceramic materials like titanium and zirconia; however, each kind of material has restrictions regarding osseointegration and mechanical characteristics that differ between native bone and the implant material, limiting the implant's longevity and reliability. To address these concerns, this research explores the use of carbon nanotubes (CNTs) in restorative dentistry, their excellent properties make them an ideal candidate for promoting bone growth around implanted device and ensuring long-lasting success. The objective of this study was to understand how CNT properties when incorporated into the titanium matrix may be able to better adapt to the oral environment taking into consideration the CNT agglomeration effects when designing reinforced nanocomposite materials for dental implant. A mathematical formulation of the micromechanics model was developed and improved to extend its application for the case of CNT-based composite materials for dental implants. A three dimensional (3D) model of bone structure around the osseointegrated dental implant was established considering different compositions of implant material. Finite Element Analysis (FEA) were conducted to assess the aggregation effect of implant incorporating CNTs into the titanium matrix, considering CNTs with both spherical inclusions (CNT clusters), and randomly dispersive ones (CNTs) in the titanium matrix, on osseointegration and bone remodeling around the dental implant and supporting bone system over a period of 48 months. Firstly, the effects of CNT-Ti implantation on time-dependent performance are evaluated in a computational remodeling framework. Then, Von Mises equivalent stresses are investigated to evaluate the stress distributions and micromotions in jaw bones of loaded implant with different composition of prosthetic material. Three agglomeration patterns are considered, particularly without agglomeration (ζ = ξ), partial and complete agglomeration (ζ < ξ, ξ = 1). Further, the influence of CNTs volume fraction variation is taken into account to predict the mechanical response of the bony system after CNT-reinforced dental implantation. It can be inferred that the agglomeration of CNTs reduces the elastic stiffness of the matrix. This is due to the fact that when CNTs are agglomerated, the inter-tube contacts are reduced and the effective stiffness of the matrix is decreased.

Effect of Implant Length and Insertion Depth on Primary Stability of Short Dental Implant

Purpose: To evaluate the effect of insertion depth, bone type, and implant diameter on the primary stability of short implants. Materials and Methods: Commercial dental implants with different lengths (6 and 8 mm; BLX, Straumann) were inserted into artificial bone specimens of good and poor quality at three different depth positions: equicrestal, 1-mm subcrestal, and 2-mm subcrestal. Insertion torque values were recorded spontaneously during the implant procedure. Both maximum insertion torque values (MITVs) and final insertion torque values (FITVs) were recorded. Subsequently, Periotest values (PTVs) and implant stability quotients (ISQs) were measured for all specimens. Results: The mean MITVs of all groups ranged from 31.8 to 46.2 Ncm. However, the mean FITVs of all groups ranged from 8.8 to 29 Ncm. Torque values decreased significantly when the implants were inserted into their final positions. When insertion depth was increased, the PTV and ISQ decreased. Long implants and implants inserted into good-quality bone yielded greater primary stability, and bone quality appeared to have a greater effect on primary stability. Conclusion: When 6-mm short implants are inserted in a subcrestal position, low primary stability may be yielded, particularly in poor-quality bone.

Morphology and microchemistry study of three commercial dental implants

Titanium and its alloys are widely employed in commercial dental devices. Because the surface morphology and chemical composition of Ti‐based dental implants play a relevant role in osseointegration, three different commercial threaded implants have been investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy (XPS). The Implants A and C were made of pure Ti whereas the Implant B was made of Ti6Al4V alloy. Obtained results evidenced the common features and differences due to specific process parameters used in the treatments of mordanting and sandblasting for surface roughening. Implant A exhibits a uniform surface covered by very small dimples of about 1–2 μm. The surface of Implant B is not homogeneous: The thread tops present an irregular morphology (dimples size &gt;10 μm) while finer dimples (about 1 μm) are observed along the thread flanks and valleys. Implant C shows an irregular morphology with dimples of different sizes and shapes distributed on thread tops, flanks, and valleys. XPS analyses revealed the presence of metal oxides: TiO2 in all the implants; Al2O3 and V2O5 only in the implant B. Moreover, these results demonstrated that Mg2SiO4 is present on the surface of Implant A, probably due to a specific preparation process. Obtained results have been discussed on the basis of the factors promoting the osseointegration.

Effect of alkaline treatment with sodium hydroxide on wettability and bioactivity of some commercial dental implants

Aim/Objectives The aim of this study was conducted to evaluate the effect of NaOH alkaline treatment on wettability and bioactivity of some commercial dental implants. Background The surface of titanium dental implants plays an important role in their success. Wettability is one of the crucial surface characteristics for osseointegration. Methods In this study, three commercial titanium dental implants are grouped by their types into 3 groups (n=10). Each group is divided into 2 subgroups (n=5) according to alkaline treatment. Each experimental specimen is immersed in 5 mL of 5M NaOH solution for 24h at 60°C, then put in an incubator for 24 h to dry at 40°C. All specimens are subjected to surface wettability test through measuring static contact angle (CA) by sessile drop technique and in vitro bioactivity test through immersion into a simulated body fluid (SBF) at 37°C and 7.4p H for 7 days. Then characterized by Scanning Electron Microscope and Energy Dispersive X-ray. Student t-test is used for pair-wise comparisons. The significance level is set at P≤0.05. Results/Conclusions The alkaline surface treatment of Ti dental implants significantly enhances their surface wettability and bioactivity by formation of a porous network structure at a nano scale from sodium titanate hydrogel layer on the surface.

Influence of Sandblasting Process on Tribological Properties of Titanium Grade 4 in Artificial Saliva for Dentistry Applications.

Titanium Grade 4 (Ti G4) is widely used in medicine for dental implants. The failure-free life of implants depends on their properties such as resistance to wear and friction processes. This paper presents an analysis of the influence of sandblasting on tribological wear of commercial dental implants made of TiG4 in artificial saliva. Tribological wear measurements were performed in a reciprocating motion in the ball-on-disc system. The scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) method was used to characterize the surface of the implants before and after the tribological wear test. The microhardness of Ti G4 was measured before and after sandblasting by the Vickers method. The contact angle was determined by the method of sitting drop in air. The residual stress test using the X-Ray Diffraction (XRD) single-{hkl} sin2ψ method was carried out. The compressive residual stress of 324(7) MPa and surface hardening of Ti G4 was revealed after sandblasting with Al2O3 particles of 53–75 μm in diameter. It was found that sandblasting changes the surface wettability of Ti G4. The intermediate wettability of the mechanically polished surface and the hydrophobicity of the sandblasted surface was revealed. Sandblasting reduces the tribological wear and friction coefficient of Ti G4 surface in saliva. The three-body abrasion wear mechanism was proposed to explain the tribological wear of Ti G4 in saliva.

Engineer design process assisted by explainable deep learning network

Engineering simulation accelerates the development of reliable and repeatable design processes in various domains. However, the computing resource consumption is dramatically raised in the whole development processes. Making the most of these simulation data becomes more and more important in modern industrial product design. In the present study, we proposed a workflow comprised of a series of machine learning algorithms (mainly deep neuron networks) to be an alternative to the numerical simulation. We have applied the workflow to the field of dental implant design process. The process is based on a complex, time-dependent, multi-physical biomechanical theory, known as mechano-regulatory method. It has been used to evaluate the performance of dental implants and to assess the tissue recovery after the oral surgery procedures. We provided a deep learning network (DLN) with calibrated simulation data that came from different simulation conditions with experimental verification. The DLN achieves nearly exact result of simulated bone healing history around implants. The correlation of the predicted essential physical properties of surrounding bones (e.g. strain and fluid velocity) and performance indexes of implants (e.g. bone area and bone-implant contact) were greater than 0.980 and 0.947, respectively. The testing AUC values for the classification of each tissue phenotype were ranging from 0.90 to 0.99. The DLN reduced hours of simulation time to seconds. Moreover, our DLN is explainable via Deep Taylor decomposition, suggesting that the transverse fluid velocity, upper and lower parts of dental implants are the keys that influence bone healing and the distribution of tissue phenotypes the most. Many examples of commercial dental implants with designs which follow these design strategies can be found. This work demonstrates that DLN with proper network design is capable to replace complex, time-dependent, multi-physical models/theories, as well as to reveal the underlying features without prior professional knowledge.

Design of metal-polymer structure for dental implants with stiffness adaptable to alveolar bone

Mechanical adaptability of implants to the surrounding alveolar bone is one of the critical factors that influences its long-term service. Experimental study shows that widely adopted titanium implants are prone to induce stress shielding due to the considerable mismatch of moduli between stiff implant and alveolar bone, which is considered to induce resorption of peri-implant bone tissues and impair the retention of implants. Moreover, current commercial dental implants with fixed stiffness are unable to meet various alveolar bone conditions of the patients of different ages and physical situations. To solve the two problems, a novel design of metal-polymer structure is proposed for dental implants, which combines two kinds of biocompatible materials, i.e., titanium and polyether-ether-ketone (PEEK). The proposed composite structure allows patient-specific adjustment of equivalent modulus for dental implant in a cost-effective way. In this paper, three designs are given and compared to show how an optimized biomechanical health degree of peri-implant bone can be achieved to fit the alveolar bone condition of patients.

Surface characteristics on commercial dental implants differentially activate macrophages in vitro and in vivo.

Biomaterial implantation provokes an inflammatory response that controls integrative fate. M2 macrophages regulate the response to implants by resolving the inflammatory phase and recruiting progenitor cells to aid healing. We have previously shown that modified titanium (Ti) disks directly induce M2 macrophage polarization. The aim of this study was to examine macrophage response to commercially available Ti or Ti alloy implants with comparable roughness and varying hydrophilicity. Eleven commercially available Ti (A-F) or Ti alloy (G-K) dental implants were examined in this study. Surface topography, chemistry, and hydrophilicity were characterized for each implant. To compare the immune response in vitro, human monocyte-derived macrophages were seeded on implants and secreted pro- and anti-inflammatory proteins measured. To evaluate the inflammatory response in vivo, mice were subcutaneously instrumented with clinical implants, and implant adherent macrophage populations were characterized by flow cytometry. Macrophages on hydrophobic Implant C produced the highest level of pro-inflammatory proteins in vitro. In contrast, hydrophilic Implant E produced the second-highest pro-inflammatory response. Implants F and K, both hydrophilics, produced the highest anti-inflammatory protein secretions. Likewise, pro-inflammatory CD80hi macrophages predominated in vivo on implants C and E, and M2 CD206+macrophages predominated on implants F and K. These findings show that hydrophilicity alone is insufficient to predict the anti-inflammatory effect on macrophage polarization and that other properties-surface composition or topography-determine immune modulation. This in vivo model may be a useful screening method to compare the immunomodulatory response to clinical implants of disparate geometry or size.

Biological and esthetic outcome of immediate dental implant with the adjunct pretreatment of immediate implants with platelet-rich plasma or photofunctionalization: A randomized controlled trial.

Aim:The purpose of the study was to assess biological and esthetic outcomes of immediate dental implant in esthetic zone with the adjunct pretreatment of immediate implants with photofunctionalization or platelet-rich plasma in comparison to standard tapered root form implant without pretreatment.Settings and Design:Patients visiting department of Prosthodontics of a tertiary care health Institution. Design of the study was randomized controlled trial.Materials and Methods:Ninety subjects who required replacement of maxillary anterior teeth immediately after extraction were selected and randomly divided into three groups: control group and two case groups. Two case groups were treated with immediate implants with pretreatment with Photofunctionalization (PF group) or platelet-rich plasma (PRP group). Delayed loading protocol was followed with prosthesis given after 6 months. Follow-up was performed at 2nd and 4th weeks and 2, 4, 6, and 12 months (P < 0.05). Biological outcomes (mean marginal bone loss, implant stability), esthetic outcome (pink esthetic score and white esthetic score), and success and survival rate were evaluated.Statistical Analysis Used:Outcomes were compared using one-way ANOVA, while intragroup changes with baseline and follow up were assesed using repeated-measures ANOVA. Statistical analyses were performed using Statistical Package for Social Sciences version 25.0 (SPSS Inc., Chicago, IL, USA). The level of significance was set at <.05.Results:Mean marginal bone loss was not significantly different in PF group and PRP group than the control group. PF group and PRP group showed significantly greater implant stability as compared to the control group. Pink and white esthetic scores were not significantly different among groups.Conclusion:Pretreatment of commercial dental implants with PF or PRP exhibited a statistically significant difference in implant stability but not with other outcomes.

Surface parameters of as-built additive manufactured metal for intraosseous dental implants

Statement of problemTo improve osseointegration, current machined implants are submitted to different surface treatments such as airborne-particle abrasion and acid etching. Although additive manufacturing has allowed the fabrication of implants with custom design, porosity, and roughness, whether good osseointegration can be achieved without subsequent surface treatments is still unclear. PurposeThe purpose of this in vitro study was to investigate the feasibility of using additive manufacturing technology for dental implants without the use of subsequent surface treatments. Material and methodsThe roughness, wettability, and surface energy of a flat test stainless-steel specimen produced from a 3D printer were evaluated. The roughness measurements were obtained by using a mechanical contact profilometer. The wettability was characterized by the sessile drop method by using deionized water and ethylene glycol. The surface energy values were calculated by using the Owens, Wendt, Rabel, and Kaeble (OWRK) computational method. ResultsThe experimental data obtained were Ra=4.55 μm, Rq=5.64 μm, RSm=0.235 mm, Rsk=-0.071, Rku=3.740, Rdq=13 degrees; water contact angle=66 degrees; ethylene glycol contact angle=57 degrees; surface energy=38 mN/m. The measured values were compared with data reported in the literature for commercially available implants. The parameter Ra, which is the most used parameter to describe the surface of dental implants, was 50%, 270%, and 329% higher than that reported in the literature for commercial dental implants. The surface energy was 10% and 19% lower than the representative values in the literature for commercial dental implants. ConclusionsThe results indicate that specimens fabricated by additive manufacturing had higher roughness and lower surface energy than reported results in the literature. Therefore, additive manufacturing was found to produce suitable surface parameters for dental implants, and subsequent surface treatments could be removed from the manufacturing process.

Achievements in the Topographic Design of Commercial Titanium Dental Implants: Towards Anti-Peri-Implantitis Surfaces.

Titanium and its alloys constitute the gold standard materials for oral implantology in which their performance is mainly conditioned by their osseointegration capacity in the host’s bone. We aim to provide an overview of the advances in surface modification of commercial dental implants analyzing and comparing the osseointegration capacity and the clinical outcome exhibited by different surfaces. Besides, the development of peri-implantitis constitutes one of the most common causes of implant loss due to bacteria colonization. Thus, a synergic response from industry and materials scientists is needed to provide reliable technical and commercial solutions to this issue. The second part of the review focuses on an update of the recent findings toward the development of new materials with osteogenic and antibacterial capacity that are most likely to be marketed, and their correlation with implant geometry, biomechanical behavior, biomaterials features, and clinical outcomes.

The chemical surface evaluation of black and white porous titanium granules and different commercial dental implants with energy-dispersive x-ray spectroscopy analysis.

The chemical surface structure of the porous titanium grafts has not been found to study in the literature on the similarity of chemical surfaces of different commercial dental implants. The purpose of this study is to investigate the chemical composition and surface energies of white (WPTG) and black porous titanium granules (PTG) by energy dispersive x-ray spectrometry (EDX) analysis to compare with different commercial dental implant surface. The surface chemical compositions of six commercially available dental implants with different surface structures, PTG and WPTG were examined by EDX analysis. Surface analyzes were performed on the apical, middle, and coronal parts of each implant and on the top, flank, and valley regions on each side. Surface analyzes of dental implants were evaluated at ×200 and ×2000 magnifications. The EDX evaluation of PTG grafts were evaluated at ×250, ×2000, ×5000, and ×50 000 magnifications. PTG grafts showed elements of Na (8.88 ± 9.98%), Cl (2.44 ± 1.96%), and Al (0.99 ± 0.37%) as well as Ti (90.06 ± 11.34%) molecule at ×5000 magnification. In WPTG, Ti (%34.55 ± 6.41%) and O (%65.44 ± 6.42%) molecules were detected. It has been found that PTG surface was not made of pure titanium, it has different chemical molecules at larger magnifications. Cell culture and experimental studies are needed to establish a relationship between the different commercial implants and the surface structure of the titanium granules.

Quantitative in vitro comparison of the thrombogenicity of commercial dental implants.

Dental implants often have surface modifications that alter surface topography and chemistry to improve osseointegration and thereby increase treatment predictability. Surface contact-induced blood coagulation is associated with the onset of osseointegration. To quantitatively evaluate the thrombogenicity of two commercially available dental implants that have similar surface roughness but different surface chemistry. Two commercially available dental implants with anodized or sandblasted acid-etched surfaces were evaluated for thrombogenic properties. Thrombogenicity was assessed by incubating implants for 1 hour in fresh, partially heparinized blood followed by hemocyte quantification, microscopic evaluation, and quantification of thrombogenic biomarkers. Fibrin coverage was significantly higher on the anodized surface compared with the sandblasted acid-etched surface (P < 0.0001). Platelet and white blood cell attachment followed a similar pattern. The increased thrombogenicity was confirmed based on a significant increase in the levels of the coagulation cascade biomarkers, thrombin antithrombin complex, and β-thromboglobulin (all P < 0.05). Dental implants with comparable roughness but differing surface chemistry had differing extents of blood contact activation. These data suggest that surface chemistry from anodization augments implant thrombogenicity compared with that from sandblasting and acid-etching, which could have implications for osseointegration.

Novel in vitro comparative model of osteogenic and inflammatory cell response to dental implants

ObjectivesRoughened dental implants promote mesenchymal stem cell (MSCs) osteoblastic differentiation, and hydrophilic modifications induce anti-inflammatory macrophages activation. While the effect of different surface modifications on osseointegration of commercial dental implants have been compared in vivo and clinically, the initial cellular response to these modifications often overlooked. We aimed to characterize the macrophage inflammatory response and MSC osteogenesis across different commercially available implants in vitro. MethodsSix commercially available rough implants [OsseoSpeed™ (Astra-Tech™, Implant A); Osseotite® (Biomet 3i™, Implant B); TiUnite™ (Nobel-Biocare®, Implant C); Ti-SLA®, (Implant D), Roxolid® (RXD-SLA, Implant E), RXD-SLActive® (Implant F) (Straumann®)] were examined. Macrophages and MSCs were seeded directly on implants and cultured in custom vials. mRNA and protein levels of pro- (IL1B, IL6, IL17A, CXCL10, TNFa) and anti- (IL4, IL10, TGFB1) inflammatory markers were measured after 24 and 48h in macrophages. Osteoblastic differentiation of MSCs was assessed after seven days by alkaline phosphatase activity, osteocalcin, and angiogenic, osteogenic, and inflammatory markers by ELISA and qPCR (n=6/variable, ANOVA, post hoc Tukey HSD with α=0.05). ResultsHydrophilic implant F induced the highest level of osteogenic factor released from MSCs and anti-inflammatory factors from macrophages with the lowest level of pro-inflammatory factors. Alternatively, implants A and C supported lower levels of osteogenesis and increased secretion of pro-inflammatory factors. SignificanceIn this study, we successfully evaluated differences in cell response to commercially available clinical implants using an in vitro model. Data from this model suggest that not all surface modification procedures generate the same cell response.

Correlation Between Implant Geometry, Implant Surface, Insertion Torque, and Primary Stability: In Vitro Biomechanical Analysis.

Primary implant stability represents the first step for successful osseointegration. The knowledge of the correlation between host bone density, insertion torque, and implant macrogeometry seems to be fundamental to achieve sufficient primary implant bone fixation in each clinical situation. The purpose of this study was to measure, in vitro, the impact of dental implant macrogeometry and insertion torque values on primary stability in relation to different bone densities, representing both the human mandible and maxilla. One hundred twenty 3.8 ± 11-mm commercial dental implants were used. Forty implants had small threads with a machined neck, 40 implants had small threads with a microthreaded neck, and the last 40 implants had large threads with a reverse neck design. Fresh bovine ribs, representing a medium-dense bone density (D2-D3), and fresh ovine iliac crest, representing a soft bone density (D4), were used. Insertion torque and micromobility under lateral force data were recorded for each implant. In the medium-dense bone type, the reverse neck implant design showed less primary implant stability than the conventional straight implant neck. In soft bone, both implants with the large thread design and microthreaded neck implants showed better implant stability than the implant with a small thread design with a straight machined neck. Implants with large and self-cutting threads showed significantly (P < .05) lower micromobility values than other implants in postextractive sites in low-density bone. Implant geometries and bone density are the main factors involved in the degree of primary implant stability. Large-thread implant designs are highly desirable in cases of poor bone quality. Each implant geometry generates an insertion torque value, which is correlated to the stability of that specific implant in a specific bone quality, but the insertion torque is not an objective value to compare primary stability between different implant types.

Osteoconductivity of Zinc-Doped Calcium Phosphate Coating on a 3D-Printed Porous Implant

Currently, most of the commercial dental implants are made from inert pure titanium which facilitates osteointegration but without bioactive properties like osteo-conductivity and osteo-inductivity. Current attempts to improve dental implant bioactivity are limited by their single action and low efficiency. These methods either just add chemical coating on implants surface or simply change surface roughness instead of combining chemical and mechanical changes together. Here, we developed an advanced titanium implants by electro-depostion of a zinc-doped calcium phosphate (Zn-HA) coating on the 3D printed porous dental implants which optimize biomechanical and biological microenvironment for new bone formation. The bioactive titanium implants enable osteoblast-like cells to attach on implants, render high proliferation days 4 and 7 after attaching (P <0.001) and the following osteogenic differentiation indicated by increase alkaline phosphatase activity at 7 days post-seeding (P <0.001), total cellular protein expression at 14 days (P <0.05), osteogenic gene mRNA expression like OCN, RUNX2, and Osterix at days 9 and 14 (P <0.001) and protein bone sialoprotein and collagen I excretion at days 9, 14 and 21. Also we found out the optimal molar ratio of Zn/(Zn+Ca) for osteointergration around implants. Overall, Zn-HA on 3D printed porous titanium has good osteoconductivity, especially when Zn/(Zn+Ca) is 20%.

Comparative evaluation of topographical data of dental implant surfaces applying optical interferometry and scanning electron microscopy

ObjectiveComparability of topographical data of implant surfaces in literature is low and their clinical relevance often equivocal. The aim of this study was to investigate the ability of scanning electron microscopy and optical interferometry to assess statistically similar 3-dimensional roughness parameter results and to evaluate these data based on predefined criteria regarded relevant for a favorable biological response. MethodsFour different commercial dental screw-type implants (NanoTite Certain Prevail, TiUnite Brånemark Mk III, XiVE S Plus and SLA Standard Plus) were analyzed by stereo scanning electron microscopy and white light interferometry. Surface height, spatial and hybrid roughness parameters (Sa, Sz, Ssk, Sku, Sal, Str, Sdr) were assessed from raw and filtered data (Gaussian 50μm and 5μm cut-off-filters), respectively. Data were statistically compared by one-way ANOVA and Tukey–Kramer post-hoc test. For a clinically relevant interpretation, a categorizing evaluation approach was used based on predefined threshold criteria for each roughness parameter. ResultsThe two methods exhibited predominantly statistical differences. Dependent on roughness parameters and filter settings, both methods showed variations in rankings of the implant surfaces and differed in their ability to discriminate the different topographies. Overall, the analyses revealed scale-dependent roughness data. Compared to the pure statistical approach, the categorizing evaluation resulted in much more similarities between the two methods. SignificanceThis study suggests to reconsider current approaches for the topographical evaluation of implant surfaces and to further seek after proper experimental settings. Furthermore, the specific role of different roughness parameters for the bioresponse has to be studied in detail in order to better define clinically relevant, scale-dependent and parameter-specific thresholds and ranges.