Influence of surface modified dental implant abutments on connective tissue attachment: A systematic review

Vacuum Plasma Treatment Device for Enhancing Fibroblast Activity on Machined and Rough Titanium Surfaces

This study was conducted to compare the effects of an innovative plasma surface treatment device that does not need a gas supply for titanium disks with two different surface topographies: the prototypical machined surface (MAC) and one of the most diffused roughened ones (SL) obtained through grit blasting and acid etching. A total of 200-MAC and 200-SL titanium disks were used. Each group of disks was divided into four sub-groups of 40 samples each that were subjected to five different tests. Among these, 150-MAC and 150-SL were considered the test group, and they were treated with plasma for 15, 30, and 60 s after being removed from the sterile packaging. On the other hand, 50-MAC and 50-SL were considered the control group, and they were only removed from sterile plastic vials. The samples were analyzed to evaluate the capability of the plasma treatment in influencing protein adsorption, cell adhesion, proliferation, and microbial growth on the test group disks when compared to the untreated disks. Protein adsorption was significantly enhanced after 20 min of plasma treatment for 15 and 30 s on the MAC and SL disks. Plasma treatment for 15 and 30 s significantly increased the level of adhesion in both treated samples after 30 min. Furthermore, the MAC samples showed a significant increase in cell adhesion 4 h after plasma treatment for 15 s. The SEM analysis highlighted that, on the treated samples (especially on the MAC disks), the cells with a polygonal and flat shape prevailed, while the fusiform- and globular-shaped cells were rare. The encouraging results obtained further confirm the effectiveness of plasma treatments on cell adhesion and fibroblast activity.

Trans-mucosal platforms for dental implants: Strategies to induce muco-integration and shield peri-implant diseases

OBJECTIVES

Trans-mucosal platforms connecting the bone-anchored implants to the prosthetic teeth are essential for the success of oral rehabilitation in implant dentistry. This region promotes a challenging environment for the successfulness of dental components due to the transitional characteristics between soft and hard tissues, the presence of bacteria, and mechanical forces. This review explored the most current approaches to modify trans-mucosal components in terms of macro-design and surface properties.

METHODS

This critical review article revised intensely the literature until July 2023 to demonstrate, discuss, and summarize the current knowledge about marketable and innovative trans-mucosal components for dental implants.

RESULTS

A large number of dental implant brands have promoted the development of several implant-abutment designs in the clinical market. The progress of abutment designs shows an optimistic reduction of bacteria colonization underlying the implant-abutment gap, although, not completely inhibited. Fundamental and preclinical studies have demonstrated promising outcomes for altered-surface properties targeting antibacterial properties and soft tissue sealing. Nanotopographies, biomimetic coatings, and antibiotic-release properties have been shown to be able to modulate, align, orient soft tissue cells, and induce a reduction in biofilm formation, suggesting superior abilities compared to the current trans-mucosal platforms available on the market.

SIGNIFICANCE

Future clinical implant-abutments show the possibility to reduce peri-implant diseases and fortify soft tissue interaction with the implant-substrate, defending the implant system from bacteria invasion. However, the absence of technologies translated to commercial stages reveals the need for findings to "bridge the gap" between scientific evidences published and applied science in the industry.

Electron Microscopy (EM) Analysis of Collagen Fibers in the Peri-Implant Soft Tissues around Two Different Abutments

The design of the implant prosthesis-abutment complex appears crucial for shaping healthy and stable peri-implant soft tissues. The aim of the present animal study was to compare two implants with different healing abutment geometries: a concave design (TEST) and a straight one (CTRL). Transmission electron microscopy (TEM) was used to quantify the three-dimensional topography and morphological properties of collagen at nanoscale resolution. 2 swine were included in the experiment and 6 implants per animal were randomly placed in the left or right hemimandible in either the physiologically mature bone present between the lower canine and first premolar or in the mandibular premolar area, within tooth extraction sites. Each CTRL implant was positioned across from its respective TEST implant on the other side of the jaw. After 12 weeks of healing, 8 specimens (4 CTRL and 4 TEST) were retrieved and prepared for histological and TEM analysis. The results showed a significantly higher percentage of area covered by collagen bundles and average bundle size in TEST implants, as well as a significant decrease in the number of longitudinally oriented bundles with respect to CTRL implants, which is potentially due to the larger size of TEST bundles. These data suggest that a concave transmucosal abutment design serves as a scaffold, favoring the deposition and growth of a well-organized peri-implant collagen structure over the implant platform in the early healing phase, also promoting the convergence of collagen fibers toward the abutment collar.

Contour Analysis of Three-Dimensional Peri-Implant Mucosal Model as an Endpoint Analysis of Photofunctionalization Effects on Implant Abutment Materials

INTRODUCTION

The objective of this study was to examine the effect of photofunctionalization on the soft-tissue contour formed at the interface of various abutment materials using end-point analyses obtained from the three-dimensional oral mucosal model (3D-OMMs).

METHODS

Commercially pure titanium (CPTi), alumina-toughened zirconia (ATZ), and yttria-stabilized zirconia (YSZ) made into discs shapes were classified into two groups: UV-treated (PTx) and non-treated (NTx). The materials in PTx groups were exposed to UV light for 12 min. Human gingival fibroblasts and TR146 epithelial cell lines co-cultured on the acellular dermal membrane were used to construct the 3D-OMM. After 4 days of culture, the discs were inserted into the holes prepared within the membrane of 3D-OMMs. The contour formed by the tissue was evaluated after 14 days of culture.

RESULTS

The UV treatment of abutment materials resulted in the formation of more non-pocket-tissue types among the PTx group (p = 0.002). Of all materials tested, soft tissue contour around YSZ showed higher scores for the non-pocket type in both non- and UV-treated groups.

CONCLUSIONS

The non-pocket type of tissue attachment was frequently found in all surfaces modified by photofunctionalization, particularly zirconia. The 3D-OMM can be used to evaluate the biological endpoints of implant surface modifications.

Nano-scaled surfaces and sustainable-antibiotic-release from polymeric coating for application on intra-osseous implants and trans-mucosal abutments

Multifunctional surfaces may display the potential to accelerate and promote the healing process around dental implants. However, the initial cellular biocompatibility, molecular activity, and the release of functionalized molecules from these novel surfaces require extensive investigation for clinical use. Aiming to develop and compare innovative surfaces for application in dental implants, the present study utilized titanium disks, which were treated and divided into four groups: machined (Macro); acid-etched (Micro); anodized-hydrophilic surface (TNTs); and anodized surface coated with a rifampicin-loaded polymeric layer (poly(lactide-co-glycolide), PLGA) (TNTsRIMP). The samples were characterized regarding their physicochemical properties and the cumulative release of rifampicin (RIMP), investigated at different pH values. Additionally, differentiated osteoblasts from mesenchymal cells were used for cell viability and qRT-PCR analysis. Antibacterial properties of each surface treatment were investigated against Staphylococcus epidermidis. TNTsRIMP demonstrated controlled drug release for up to 7 days in neutral pH environments. Osteogenic cell cultures indicated that all the evaluated surfaces showed biocompatibility. The TNTs group revealed up-regulated values for bone-related gene quantification in 7 days, followed by the TNTsRIMP group. Furthermore, the antibiotic-functionalized surface revealed effectiveness to inhibit S. epidermidis and stimulate promising conditions for osteogenic cell behavior. Characteristics such as nanomorphology and hydrophilicity were determinants for the up-regulated quantification of osteogenic biomarkers related to early bone maturation, encouraging application in intra-osseous implant surfaces; in addition, antibiotic-functionalized surfaces demonstrated significant higher antibacterial properties compared to the other groups. Our findings suggest that polymeric-antibiotic-loaded coating might be applied for the prevention of early infections, favoring its application in multifunctional surfaces for intra- and/or trans-mucosal components of dental implants, while, hydrophilic nanotextured surfaces promoted optimistic properties to stimulate early bone-related cell responses, favoring its application in bone-anchored surfaces.

Laser microgrooving and resorbable blast texturing for enhanced surface function of titanium alloy for dental implant applications

Long-term dental implant success is dependent on biocompatibility and osseointegration between the bone and the implant. Surface modifications such as laser-induced microgrooving which increase contact area can enhance osseointegration by establishing and directing a stable attachment between the implant surface and peri-implant bone. The objective of this study was to evaluate pre-osteoblast proliferation, morphology, and differentiation on titanium alloy (Ti64) surfaces-Laser-Lok^© (LL), resorbable blast textured (RBT), and machined (M)-compared to tissue culture plastic (TCP) control. We hypothesized the LL surfaces would facilitate increased cellular alignment compared to all other groups, and LL and RBT surfaces would demonstrate enhanced proliferation and differentiation compared to M and TCP surfaces. Surface roughness was quantified using a surface profilometer, and water contact angle was measured to evaluate the hydrophilicity of the surfaces. Cellular function was assessed using quantitative viability and differentiation assays and image analyses, along with qualitative fluorescent (viability and cytoskeletal) imaging and scanning electron microscopy. No differences in surface roughness were observed between groups. Water contact angle indicated LL was the least hydrophilic surface, with RBT and M surfaces exhibiting greater hydrophilicity. Cell proliferation on day 2 was enhanced on both LL and RBT surfaces compared to M, and all three groups had higher cell numbers on day 2 compared to day 1. Cell orientation was driven by the geometry of the surface modification, as cells were more highly aligned on LL surfaces compared to TCP (on day 2) and RBT (on day 3). At day 21, cell proliferation was greater on LL, RBT, and TCP surfaces compared to M, though no differences in osteogenic differentiation were observed. Collectively, our results highlight the efficacy of laser microgrooved and resorbable blast textured surface modifications of Ti64 for enhancing cellular functions, which may facilitate improved osseointegration of dental implants.

Strontium-loaded hydrogel scaffolds to promote gingival fibroblast function

Dental implant clinical success is dependent on effective peri-implant tissue attachment to the trans-mucosal portion following placement. Modification of transmucosal implant surfaces can improve cellular adhesion and function leading to formation of an effective soft-tissue seal during healing, of which gingival fibroblasts are prominent cells to migrate to repair wounds and crucial for the development of a collagen rich connective tissue. Biocompatible loaded scaffold materials have been developed to allow local release of molecules with effective biological activity. Our previous studies indicate that strontium can promote gingival fibroblast metabolism, decrease apoptosis and support adhesion to titanium healing abutments. In this study, we developed a strontium-loaded alginate hydrogel scaffold which can be easily personalized to fit over any size and shape of implant transmucosal collar or healing abutment. Results indicate that biologically active strontium ions are effectively released from loaded alginate hydrogel material to promote fibroblast viability and migration to repair in vitro wounds similar to that of strontium citrate solution. Overall, this novel strontium-loaded alginate scaffold device displays good biocompatibility and functionality, demonstrating high potential as a system to provide local delivery of strontium to improve peri-implant mucosal healing following implant placement and clinical success.

Role of chitosan in titanium coatings. trends and new generations of coatings

Survival studies of dental implants currently reach high figures. However, considering that the recipients are middle-aged individuals with associated pathologies, research is focused on achieving bioactive surfaces that ensure osseointegration. Chitosan is a biocompatible, degradable polysaccharide with antimicrobial and anti-inflammatory properties, capable of inducing increased growth and fixation of osteoblasts around chitosan-coated titanium. Certain chemical modifications to its structure have been shown to enhance its antibacterial activity and osteoinductive properties and it is generally believed that chitosan-coated dental implants may have enhanced osseointegration capabilities and are likely to become a commercial option in the future. Our review provided an overview of the current concepts and theories of osseointegration and current titanium dental implant surfaces and coatings, with a special focus on the in vivo investigation of chitosan-coated implants and a current perspective on the future of titanium dental implant coatings.

Biomechanical evaluations of the long-term stability of dental implant using finite element modeling method: a systematic review

PURPOSE

The aim of this study is to summarize various biomechanical aspects in evaluating the long-term stability of dental implants based on finite element method (FEM).

MATERIALS AND METHODS

A comprehensive search was performed among published studies over the last 20 years in three databases; PubMed, Scopus, and Google Scholar. The studies are arranged in a comparative table based on their publication date. Also, the variety of modeling is shown in the form of graphs and tables. Various aspects of the studies conducted were discussed here.

RESULTS

By reviewing the titles and abstracts, 9 main categories were extracted and discussed as follows: implant materials, the focus of the study on bone or implant as well as the interface area, type of loading, element shape, parts of the model, boundary conditions, failure criteria, statistical analysis, and experimental tests performed to validate the results. It was found that most of the studied articles contain a model of the jaw bone (cortical and cancellous bone). The material properties were generally derived from the literature. Approximately 43% of the studies attempted to examine the implant and surrounding bone simultaneously. Almost 42% of the studies performed experimental tests to validate the modeling.

CONCLUSION

Based on the results of the studies reviewed, there is no "optimal" design guideline, but more reliable design of implant is possible. This review study can be a starting point for more detailed investigations of dental implant longevity.

Sulcus fluid volume, IL-6, and Il-1b concentrations in periodontal and peri-implant tissues comparing machined and laser-microtextured collar/abutment surfaces during 12 weeks of healing: A split-mouth RCT

OBJECTIVES

To compare gingival tissue healing at surgically manipulated periodontal sites and at sites receiving implants and healing abutments with machined (MS) vs laser-microtextured (LMS) surface placed with one-stage protocol.

MATERIAL AND METHODS

Twenty-four non-smoking patients each received two implants with one-stage protocol in a split-mouth design on the same jaw. In each patient, one implant with a MS collar and one immediate healing abutment with a MS, and one implant with a LMS collar and one immediate healing abutment with a LMS were used. Soft tissues healing at surgically manipulated periodontal tissues (T+) and at non-surgically manipulated periodontal tissues (T-) at MS implant sites and at LMS implant sites were compared by means of clinical and biochemical parameters at baseline and at 1-2-3-4-6-8 and 12 weeks.

RESULTS

PD and BoP mean values were statistically higher in MS than LMS implant sites (p<0.05). During early healing phase (1-4 weeks), MS and LMS peri-implant tissues and periodontal tissues at T(+) showed no statistically significant difference in crevicular fluid volume changes (p>0.05). Between 6 and 12 weeks, compared with T(+), no statistically significant difference in crevicular fluid volume and IL-6 and IL-1β concentrations was noted in LMS implant sites (p>0.05), while statistically significantly higher mean values were noted in MS implant sites (p<0.05).

CONCLUSIONS

Compared with T(+) and T(-), both MS and LMS implant sites presented a higher pro-inflammatory state in the early phase after surgery (1-4 weeks). At 12 weeks, only MS implant sites kept a higher pro-inflammatory state, while at LMS implant sites, it becomes similar to T(+) and T(-).

Biocompatibility of Lithium Disilicate and Zirconium Oxide Ceramics with Different Surface Topographies for Dental Implant Abutments

Gingivafibroblasts were cultured on lithium disilicate, on zirconia dioxide, and on titanium with two different surface roughnesses (0.2 µm and 0.07 µm); Proliferation (MTT), Living/Dead staining, cytotoxicity (LDH), proliferation (FGF2), and inflammation (TNFα) were analyzed after 1 day and 21 days. Furthermore, alteration in cell morphology (SEM) was analyzed. The statistical analysis was performed by a Kruskal-Wallis test. The level of significance was set at p < 0.05. There were no distinct differences in cellular behavior between the tested roughness. There were slight differences between tested materials. Cells grown on zirconia dioxide showed higher cytotoxic effects. Cells grown on lithium disilicate showed less expression of TNFα compared to those grown on zirconia dioxide or titanium. These effects persisted only during the first time span. The results indicate that the two tested high-strength ceramics and surface properties are biologically suitable for transmucosal implant components. The findings may help clinicians to choose the most appropriate biomaterial as well as the most appropriate surface treatment to use in accordance with specific clinical dental applications.

Extracellular-Vesicle-Based Coatings Enhance Bioactivity of Titanium Implants-SurfEV

Extracellular vesicles (EVs) are nanoparticles released by cells that contain a multitude of biomolecules, which act synergistically to signal multiple cell types. EVs are ideal candidates for promoting tissue growth and regeneration. The tissue regenerative potential of EVs raises the tantalizing possibility that immobilizing EVs on implant surfaces could potentially generate highly bioactive and cell-instructive surfaces that would enhance implant integration into the body. Such surfaces could address a critical limitation of current implants, which do not promote bone tissue formation or bond bone. Here, we developed bioactive titanium surface coatings (SurfEV) using two types of EVs: secreted by decidual mesenchymal stem cells (DEVs) and isolated from fermented papaya fluid (PEVs). For each EV type, we determined the size, morphology, and molecular composition. High concentrations of DEVs enhanced cell proliferation, wound closure, and migration distance of osteoblasts. In contrast, the cell proliferation and wound closure decreased with increasing concentration of PEVs. DEVs enhanced Ca/P deposition on the titanium surface, which suggests improvement in bone bonding ability of the implant (i.e., osteointegration). EVs also increased production of Ca and P by osteoblasts and promoted the deposition of mineral phase, which suggests EVs play key roles in cell mineralization. We also found that DEVs stimulated the secretion of secondary EVs observed by the presence of protruding structures on the cell membrane. We concluded that, by functionalizing implant surfaces with specialized EVs, we will be able to enhance implant osteointegration by improving hydroxyapatite formation directly at the surface and potentially circumvent aseptic loosening of implants.

Application of digital prosthodontics and connective tissue grafting in the management of peri-implant mucosal recession around a malpositioned 1-piece implant: A clinical report

This clinical report describes a conservative approach to improve an unesthetic implant-supported crown and peri-implant mucosal recession around a malpositioned, 1-piece implant in the maxillary right central incisor region by using digital technology. In such clinical situations, the implants are usually removed because of an unpredictable definitive esthetic outcome. However, this clinical report describes the preservation of such a compromised implant by improving the esthetic outcome with a connective-tissue graft, and a digital approach used a 1-step preformed zirconia coping technique with an appropriate emergence profile.

Effects of EGF-coated titanium surfaces on adhesion and metabolism of bisphosphonate-treated human keratinocytes and gingival fibroblasts

OBJECTIVE

To assess the effects of epidermal growth factor (EGF)-coated titanium (Ti) discs on the adhesion and metabolism of keratinocytes and gingival fibroblasts exposed to nitrogen-containing bisphosphonates.

MATERIALS AND METHODS

Keratinocytes and fibroblasts were seeded (1 × 10⁵ cells/disc) on Ti discs coated with EGF (100 nM). After 24 h, cells were exposed or not to sodium alendronate (SA) or zoledronic acid (ZA) at different concentrations (0 = control, 0.5, 1, or 5 μM) for 48 h. Cell adhesion to the substrates was evaluated by fluorescence microscopy. Cell viability (alamarBlue, n = 6) and synthesis of vascular endothelial growth factor (VEGF), matrix metalloproteinase-2 (MMP-2), and keratinocytes growth factor (KGF) (ELISA, n = 6) were assessed. Data were statistically analyzed by one-way ANOVA and Tukey tests (α = 0.05).

RESULTS

Higher cell adhesion rate was observed when keratinocytes and fibroblasts were seeded onto EGF-coated discs in comparison to uncoated discs. ZA treatment hindered the adhesion of both cell lines on the Ti discs as well as reduced the viability and synthesis of VEGF, KGF and MMP-2 by cells (p < 0.05). SA treatment did not affect cell viability, but interfered negatively on the adhesion and synthesis of EGF and KGF by the cells (p < 0.05). EGF-coated surface increased cell viability and synthesis of growth factors as well as downregulated the synthesis of MMP-2 in comparison to control (p < 0.05).

CONCLUSION

EGF applied on Ti surface improves the biological responses of oral mucosa cells exposed to SA and ZA.

CLINICAL RELEVANCE

EGF-coating on titanium may be a suitable strategy to improve oral mucosa cellular events related to biological sealing, especially for patients under bisphosphonate therapy.

Laser surface texturing of zirconia-based ceramics for dental applications: A review

Laser surface texturing is widely explored for modifying the surface topography of various materials and thereby tuning their optical, tribological, biological, and other surface properties. In dentistry, improved osseointegration has been observed with laser textured titanium dental implants in clinical trials. Due to several limitations of titanium materials, dental implants made of zirconia-based ceramics are now considered as one of the best alternatives. Laser surface texturing of zirconia dental implants is therefore attracting increasing attention. However, due to the brittle nature of zirconia, as well as the metastable tetragonal ZrO₂ phase, laser texturing in the case of zirconia is more challenging than in the case of titanium. Understanding these challenges requires different fields of expertise, including laser engineering, materials science, and dentistry. Even though much progress was made within each field of expertise, a comprehensive analysis of all the related factors is still missing. This review paper provides thus an overview of the common challenges and current status on the use of lasers for surface texturing of zirconia-based ceramics for dental applications, including texturing of zirconia implants for improving osseointegration, texturing of zirconia abutments for reducing peri-implant inflammation, and texturing of zirconia restorations for improving restoration retention by bonding.

Crystallinity of TiO2 nanotubes and its effects on fibroblast viability, adhesion, and proliferation

Titanium and titanium alloys are widely used as a biomaterial due to their mechanical strength, corrosion resistance, low elastic modulus, and excellent biocompatibility. TiO₂ nanotubes have excellent bioactivity, stimulating the adhesion, proliferation of fibroblasts and adipose-derived stem cells, production of alkaline phosphatase by osteoblasts, platelets activation, growth of neural cells and adhesion, spreading, growth, and differentiation of rat bone marrow mesenchymal stem cells. In this study, we investigated the functionality of fibroblast on titania nanotube layers annealed at different temperatures. The titania nanotube layer was fabricated by potentiostatic anodization of titanium, then annealed at 300, 530, and 630 °C for 5 h. The resulting nanotube layer was characterized using SEM (Scanning Electron Microscopy), TF-XRD (Thin-film X-ray diffraction), and contact angle goniometry. Fibroblasts viability was determined by the CellTiter-Blue method and cytotoxicity by Lactate Dehydrogenase test, and the cell morphology was analyzed by scanning electron microscopy. Also, cell adherence, proliferation, and morphology were analyzed by fluorescence microscopy. The results indicate that the modification in nanotube crystallinity may provide a favorable surface fibroblast growth, especially on substrates annealed at 530 and 630 °C, indicating that these properties provide a favorable template for biomedical implants.

Er,Cr:YSGG laser surface treatment of gamma titanium aluminide: Scanning electron microscopy-energy-dispersive X-ray spectrometer analysis, wettability and Eikenella corrodens and Aggregatibacter actinomycetemcomitans bacteria count-in vitro study

Dental implants play an important role in oral health. Titanium dental implants must endure the complex microflora environment of the oral cavity. Moreover, bacterial infections have been considered as one of the most important factors of implant failure. The issue of dental improvement through modification of chemical composition and surface treatment has received considerable critical attention. γ-TiAl as a novo biocompatible material revealed a slower corrosion rate in biological media rather Ti-6Al-4V. The objective of this study is to investigate the effect of Er,Cr:YSGG laser on γ-TiAl in comparison with sandblasted and acid-etched samples as the control groups and machined samples.Wettability, surface roughness, surface topography, scanning electron microscopy-energy dispersive X-ray spectrometer analysis of surface and subsurface of samples were investigated and bacteria counts of two periodontal bacterial strains (Aggregatibacter actinomycetemcomitans and Eikenella corrodens) were evaluated on the Er,Cr:YSGG laser surface-treated sandblasted and acid-etched and machined samples.The results of this investigation show that Er,Cr:YSGG laser surface treatment affects surface roughness, surface topography, wettability, chemical composition of the surface and bacteria count. Scanning electron microscopy-energy dispersive X-ray spectrometer analysis of the sample revealed the increment of titanium and oxygen content and reduction of aluminum content in the surface and subsurface layer. A. actinomycetemcomitans and E. corrodens count were found from the lowest level to highest in the sandblasted and acid-etched samples, laser samples and machined samples, respectively.Using controlled parameters of Er,Cr:YSGG laser ensured no significant adverse alteration. The findings to emerge from this study revealed the significant correlation between microbial count and wettability. Furthermore, the contact angle strongly correlated with surface roughness.

Viability and collagen secretion by fibroblasts on titanium surfaces with different acid-etching protocols

BACKGROUND

From the consolidation of surface treatments of dental implants and knowledge on the cellular mechanisms of osseointegration, studies have highlighted the importance of a connective tissue seal against the implant to prevent contamination from the oral environment and consequent biofilm formation.

OBJECTIVE

This in vitro study aimed to evaluate whether different titanium surface treatments using acid solutions promoted an increase in collagen secretion, proliferation, and viability of fibroblasts.

MATERIAL AND METHODS

Commercially pure grade-4 titanium disks (6 × 2 mm) were treated with different acid solutions (hydrochloric, nitric, and sulfuric) for 20 and 60 min, respectively, obtaining mean surface roughness of 0.1 to 0.15 μm and 0.5 to 0.7 μm. Human fibroblasts were seeded onto different surfaces and assessed after 24 h, 48 h, and 72 h for cell proliferation and viability using Trypan blue staining and MTT, respectively, as well as the secretion of type I collagen on to such surfaces using ELISA. Machined titanium surfaces were used as controls. Data were statistically analyzed using one-way ANOVA and Fisher's LSD test for multiple comparisons, adopting a significance level of 5%.

RESULTS

No significant difference was observed in cell proliferation for the different surfaces analyzed. Cell viability was significantly lower on the machined surface, after 48 h, when compared to the groups treated with acid for 20 or 60 min, which did not differ from each other. The expression of type I collagen was lowest on the acid-treated surfaces.

CONCLUSION

The results showed that the acid treatment proposed did not promote fibroblast proliferation and viability nor favor type I collagen synthesis.

Characterization of titanium surface coated with epidermal growth factor and its effect on human gingival fibroblasts

OBJECTIVES

Different strategies, such as modifications on the implant abutments surface have been proposed to accelerate and improve the formation of the biological seal (BS). The aim of this study was to characterize a titanium (Ti) surface impregnated with epidermal growth factor (EGF) and to assess its influence on the metabolism and adhesion of oral mucosal cells.

DESIGN

Ti discs were coated with EGF (100 nM) conjugated with a fluorophore and analyzed by fluorescence microscopy. The surface roughness analysis (Ra) of the EGF-coated Ti was performed by confocal microscopy. The EGF released in the wet environment was determined at 0, 24, 48 and 72 h by fluorimetric quantification. For assessment of the biological effects of EGF-coated Ti, gingival fibroblasts were seeded (5 × 10⁴ cells) onto the substrate coated or not with this growth factor. After 24 h, cell adhesion and viability were evaluated by ANOVA and Tukey tests, α = .05.

RESULTS

Immediate release of EGF as well as its incorporation by fibroblasts within 1 h after cells were seeded was observed. EGF-coated Ti discs presented significantly enhance surface roughness. Increased cell viability was observed on the EGF-coated discs.

CONCLUSION

EGF applied to Ti discs stimulated the adhesion and metabolism of gingival fibroblasts and could be considered as an interesting alternative for improving the BS.

Safety and efficacy of a novel anodized abutment on soft tissue healing in Yucatan mini-pigs

BACKGROUND

It is well established that electrochemical anodization of implant surfaces contributes to osseointegration and long-term implant survival. Few studies have investigated its effect on soft tissue healing.

PURPOSE

To evaluate the safety and efficacy of a novel abutment surface prepared by electrochemical oxidation compared to commercially available machined titanium abutments.

MATERIALS AND METHODS

Twelve 16-19 months-old, Yucatan mini-pigs received three dental implants in each mandibular jaw quadrant. Each side was randomized to receive either an anodized or a machined titanium abutment. Titanium healing caps were placed on both abutments. Animals were euthanized at 6 and 13 weeks. Radiographic and histological analyses were performed.

RESULTS

No significant differences were observed histologically between groups in regard to inflammation, epithelium length, mucosal height, bone-to-implant contact, or bone density for any time point. Radiographically, crestal bone level change from baseline to 6 weeks was significantly lower for anodized than machined abutments (P = 0.046); no significant differences were observed at 13 weeks (P = 0.12).

CONCLUSIONS

The novel anodized abutment showed a comparable effect on soft and hard tissue healing/remodeling and inflammation reaction to standard titanium abutments. Clinical studies should confirm these findings and explore the positive radiographic results observed at the early time point.

Effects of air abrasive decontamination on titanium surfaces: A systematic review of in vitro studies

BACKGROUND

Air abrasion (AA) is one of the decontamination methods that have demonstrated promising results in treating peri-implant diseases.

PURPOSE

This systematic review aimed at evaluating the in vitro effect of AA on surface change, cleaning efficacy, and biocompatibility of titanium surfaces and at comparing it with other decontamination methods.

MATERIALS AND METHODS

A comprehensive search was conducted up to April 2018 using PubMed, Scopus, and Google Scholar databases to identify studies on the decontamination effect of AA. All types of titanium surfaces, abrasive powders, contaminated surfaces, and measuring methods were included.

RESULTS

Overall, 1502 articles were identified. After screening the titles and abstracts, and carefully reading the full-texts, 48 articles published between 1989 and 2018 were selected. AA was considered almost safe, particularly for the nonmodified surfaces. Nevertheless, harder powders such as sodium bicarbonate tended to damage the surface more than glycine. AA resulted in surface change similar to plastic curettes and Er: YAG lasers. Regarding the cleaning efficacy, there was no significant difference between glycine and sodium bicarbonate, but different mixtures of calcium phosphate, hydroxyapatite, and erythritol were superior to glycine. AA was superior or equal to all other decontamination methods in cleaning. Regarding biocompatibility, AA was more successful in preserving biocompatibility for noncontaminated surfaces compared with contaminated surfaces and when used with erythritol and osteoinductive powders.

CONCLUSIONS

AA can efficiently remove contamination without serious damage to the surface. The main drawback of the AA method seems to be its limitation in restoring the biocompatibility of the surface.