SLA Surface Research Articles

Activation of Osteoblastic Function on Titanium Surface with Titanium-Doped Hydroxyapatite Nanoparticle Coating: An In Vitro Study.

Titanium-doped hydroxyapatite (TiHA) nanoparticles contain titanium atoms in the hydroxyapatite lattice, which can physicochemically functionalize the titanium surface without modification of the surface topography. This study aimed to evaluate the physicochemical properties of machined or microroughened titanium surfaces coated with TiHA nanoparticles and the functions of osteoblasts cultured on them. Titanium disks with commercially available surface topography, such as machined or sandblasted, large-grit, and acid-etched (SLA) surfaces, were coated with TiHA. The disks with original or TiHA-coated surfaces were evaluated in topography, wettability, and chemical composition. Osteoblastic cells from rat femurs were cultured on the disks and evaluated in proliferation and differentiation. TiHA coating changed from hydrophobicity to hydrophilicity on both machined and SLA surfaces. Calcium and phosphate atoms were detected all over the surface with TiHA coating regardless of the surface topography. However, the considerable change in the inherent surface topographies was not observed on both types of surfaces after TiHA coating. Osteoblastic proliferative activity at day 4 was increased by TiHA coating on both types of surfaces. TiHA coating did not enhance expressions of bone matrix-related genes such as osteocalcin, osteopontin, bone sialoprotein, alkaline phosphatase, and collagen I. However, depositions of collagen, osteocalcin, and calcium in the culture at days 7 and 20 were increased on both types of surface topographies with TiHA coating. TiHA coating enhanced extracellular matrix formation on smooth and microroughened titanium surfaces by increasing osteoblastic proliferative activity without the deterioration of differentiation through hydrophilic and chemical functionalization.

Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet Laser Effectively Ablates Single-Species Biofilms on Titanium Disks Without Detectable Surface Damage.

Increasing evidence implicates biofilms, consisting of species such as Porphyromonas gingivalis (Pg), in the etiology of peri-implantitis. Multiple approaches to ablate biofilms on failing implants have been proposed and include use of lasers, most recently the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser. The purpose of this study is to establish an in vitro single-species biofilm model on implant surfaces and determine power settings of the Er,Cr:YSGG laser that remove biofilm without causing physical damage to disks. Single-species biofilms consisting of Pg strain 381 were grown on titanium disks, including: 1) sandblasted, large-grit, acid-etched (SLA); 2) calcium phosphate nano-coated (CaP); 3) anodized; or 4) machined surfaces. Power settings from 0 to 1.5 W using an Er,Cr:YSGG laser equipped with radial firing tip were used. Biofilm formation/removal was quantitated using confocal and scanning electron microscopy. Surface changes in temperature, microroughness, and water contact angle were analyzed. Results show confluent Pg biofilm coating all disk surfaces. The laser removed biofilms from all surfaces, with CaP and SLA surfaces requiring power setting of 1.0 to 1.5 W for ablation of bacteria coating the disks. Within this power range, and with water spray, there were no changes in surface temperature, surface roughness, or contact angle on any surfaces tested. The Er,Cr:YSGG laser with radial firing tip and water spray was able to effectively ablate ≥95% of biofilm on all types of tested titanium surfaces, using clinically relevant power settings, without causing measurable physical changes to surfaces.

Bone Morphogenetic Protein 2 Alters Osteogenesis and Anti-Inflammatory Profiles of Mesenchymal Stem Cells Induced by Microtextured Titanium In Vitro.

Microtextured titanium (Ti) induces osteoblast differentiation of mesenchymal stem cells (MSCs) in the absence of exogenous osteogenic factors; and high-energy surface modifications speed healing of microrough Ti implants. Bone morphogenetic protein 2 (BMP2) is used clinically to improve peri-implant bone formation and osseointegration but can cause inflammation and bone-related complications. In this study, we determined whether BMP2 alters human MSC differentiation, apoptosis, and inflammatory factor production when grown on Ti implants with different surface properties. Human MSCs were cultured on Ti substrates (smooth [PT], sandblasted acid-etched [SLA], hydrophilic-SLA [modSLA]), or tissue culture polystyrene (TCPS). After 7 days, inflammatory mRNAs were measured by polymerase chain reaction array. In addition, 7-day cultures were treated with exogenous BMP2 and osteogenic differentiation and production of local factors, proinflammatory interleukins, and anti-inflammatory interleukins assessed. Finally, osteogenic markers and interleukins were measured in MSCs cultured for 48 h on BMP2 dip-coated SLA and modSLA surfaces. Expression of interleukins, chemokines, cytokines, and growth factors was affected by surface properties, particularly on modSLA. MSCs on Ti produced fewer resorptive and more osteogenic/anti-inflammatory factors than cells on TCPS. Addition of 100 ng/mL BMP2 not only increased differentiation but also increased proinflammatory and decreased anti-inflammatory/antiresorptive factors. Two hundred nanograms per milliliter BMP2 abolished osteogenesis and dramatically increased pro-osteoclastogenic factors. MSCs cultured on BMP2-dip-coated disks produced similar proinflammatory profiles with inhibited osteogenic differentiation and had increased apoptotic markers at the highest doses. MSCs underwent osteogenesis and regulated inflammatory cytokines on microtextured Ti. Exogenous BMP2 inhibited MSC differentiation and stimulated a dose-dependent proinflammatory and apoptotic response. Use of BMP2 with microtextured metal implants may increase inflammation and possibly delay bone formation dependent on dose, suggesting that application of BMP2 clinically during implant insertion may need to be reevaluated.

Preparation and Property of PDA/CPP Bilayer on SLA Surfaces

Preparation and Property of PDA/CPP Bilayer on SLA Surfaces

Effects of Titanium Surface Microtopography and Simvastatin on Growth and Osteogenic Differentiation of Human Mesenchymal Stem Cells in Estrogen-Deprived Cell Culture.

This study aimed to investigate the effects of titanium surface topography and simvastatin on growth and osteogenic differentiation of human bone marrow stromal cells (hBMSCs) in estrogen-deprived (ED) cell culture. Human BMSCs were seeded on cell culture plates, smooth-surface titanium (Ti) disks, and sandblasted with large grits and acid etched (SLA)-surface Ti disks; and subsequently cultured in regular (fetal bovine serum [FBS]), ED, and ED-with 100 nM simvastatin (ED-SIM) culture media for 14 to 21 days. Live/dead cell staining, scanning electron microscope examination, and cell viability assay were performed to determine cell attachment, morphology, and growth. Expression levels of osteoblast-associated genes, Runx2 and bone sialoprotein and levels of alkaline phosphatase (ALP) activity, calcium content, and osteocalcin in culture media were measured to determine osteoblastic differentiation. Expression levels of bone morphogenetic protein-2 (BMP-2) were investigated to examine stimulating effects of simvastatin (n = 4 to 5, mean ± SD). In vitro mineralization was verified by calcein staining. Human BMSCs exhibited different attachment and shapes on smooth and SLA titanium surfaces. Estrogen-deprived cell culture decreased cell attachment and growth, particularly on the SLA titanium surface, but cells were able to grow to reach confluence on day 21 in the ED-osteogenic (OS) culture medium. Promoting effects of the SLA titanium surface in ED-OS were significantly decreased. Simvastatin significantly increased osteogenic differentiation of human BMSCs on the SLA titanium surface in the ED-OS medium, and the promoting effects of simvastatin corresponded with the increasing of BMP-2 gene expression on the SLA titanium surface in ED-OS-SIM culture medium. The ED cell culture model provided a well-defined platform for investigating the effects of hormones and growth factors on cells and titanium surface interaction. Titanium, the SLA surface, and simvastatin synergistically promoted osteoblastic differentiation of hBMSCs in ED condition and might be useful to promote osteointegration in osteoporotic bone.

Effect of enamel matrix derivative on the angiogenic behaviors of human umbilical vein endothelial cells on different titanium surfaces.

Angiogenesis play a crucial role in the regeneration of hard and soft tissue around dental titanium (Ti) implant. Enamel matrix derivative (EMD) promotes tissue regeneration and stimulates angiogenesis but its effect on the angiogenesis on Ti surfaces was never investigated. The effect of EMD on the angiogenic activity of endothelial cells cultured on pre-treated smooth Ti (PT), acidetched (A), coarse-grit blasted and acid-etched (SLA) surfaces and tissue culture plastic (TCP) in the presence or absence of EMD was investigated. EMD inhibited the proliferation/viability of human umbilical vein endothelial cells (HUVECs) growing on A and SLA Ti surfaces. EMD induced an increase in the expression of all these genes in HUVECs grown on SLA surface but not on other surfaces. Summarizing, our data show that EMD influences proliferation and expression of angiogenesis associated gene in HUVECs grown on moderately rough SLA surfaces, suggesting that EMD might promote angiogenesis following implantation.

A resonance frequency analysis of sandblasted and acid-etched implants with different diameters: a prospective clinical study during the initial healing period.

PurposeThe possibility of immediate or early loading has become popular in implant dentistry. A prerequisite for the immediate or early loading of an implant prosthesis is the achievement of initial stability in the implant. Moreover, in response to clinicians' interest in verifying clinical stability to determine the optimal time point for functional loading, a non-invasive method to assess implant stability has been developed on the basis of resonance frequency analysis (RFA). The primary objective of this study was to monitor the stability of sandblasted, large-grit, and acid-etched (SLA) implants with different diameters during the early phases of healing by RFA. The secondary objective was to evaluate how the initial stability of implants varied depending on different surface modifications and other contributing factors.MethodsThirty-five implants (25 SLA implants and 10 resorbable blasting media [RBM] implants) placed in 20 subjects were included. To measure implant stability, RFA was performed at baseline and at 1, 2, 3, 4, 6, and 10 weeks after surgery.ResultsThe longitudinal changes in the implant stability quotient (ISQ) values were similar for the SLA implants with different diameters and for the RBM implants. During the initial healing period, the ISQ decreased after installation and reached its lowest values at 1 week and 2 weeks, respectively. The mean ISQ values in the SLA implants were significantly higher in Ø 5.0 mm implants than in Ø 4.0 mm implants. Men showed a higher ISQ than women. Mandibular sites showed a higher ISQ than maxillary sites.ConclusionsAll implants used in this study are suitable for immediate or early loading under appropriate indications. A wider diameter and SLA surface treatment of implants could improve the stability, if the implant is fixed with at least 30 Ncm of insertion torque.

Enhanced osteointegration of tantalum-modified titanium implants with micro/nano-topography

Ta modification enhanced the osteointegration of an SLA surface with micro/nano topography and the possible mechanism might be activation of the Wnt pathway.

The influence of implantoplasty on the diameter, chemical surface composition, and biocompatibility of titanium implants.

The objective of the study was to assess the influence of implantoplasty (IP) on the diameter, chemical surface composition, and biocompatibility of titanium implants in vitro. Twenty soft tissue-level (TL; machined transmucosal-M and rough endosseous part-SLA) and 20 bone-level (BL; SLA) implants were allocated to IP covering 3 or 6mm of the structured surface (SLA) area. The samples were subjected to diameter, energy-dispersive X-ray spectroscopy (EDX), and cell viability (ginigval fibroblasts, 6days) assessments. Median diameter reductions varied between 0.1 (TL 3mm) and 0.2mm (TL 6mm). EDX analysis revealed that IP and M surfaces were characterized by a comparable quantity (Wt%) of elements C, O, Na, Cl, K, and Si, but a significantly different quantity of elements Ti and Al. When compared to SLA surfaces, significant differences were noted for elements C, O, Na, Ti, and Al. At BL implants, the extension of IP (i.e., 3 to 6mm) was associated with a significant increase in cell viability. IP applied to SLA implants was associated with (i) a minimal diameter reduction, (ii) an undisturbed cell viability, and (iii) a chemical elemental composition comparable to M surfaces. This specific IP procedure appears to be suitable for the management of exposed SLA implant surfaces.

Enhancement of osseointegration by direct coating of rhBMP-2 on target-ion induced plasma sputtering treated SLA surface for dental application.

Owing to the excellent bioactive properties of recombinant human bone morphogenetic proteins (rhBMPs), dentistry considers them as a fascinating adjuvant alternative for enhancing bone regeneration and bone-to-implant junction in the early implantation stages. However, stable loading and delivery efficiency of rhBMPs on the implant surfaces involve major concerns because of the harsh wearing condition under load during implantation. In this study, to achieve successful rhBMP-2 delivery, a nanoporous surface structure is introduced on the sandblasting with large grit and acid-etching (SLA)-treated titanium (Ti) surface via the tantalum (Ta) target-ion induced plasma sputtering (TIPS) technique. Unlike oxidation-induced surface nanoporous fabrications on a Ti surface, TIPS-treated surfaces provide excellent structural unity of the nanoporous structure with the substrate due to their etching-based fabrication mechanism. SLA/TIPS-treated Ti exhibits distinct nanoporous structures on the microscale surface geometry and better hydrophilicity compared with SLA-treated Ti. A sufficiently empty nanoporous surface structure combined with the hydrophilic property of SLA/TIPS-treated Ti facilitates the formation of a thick and uniform coating layer of rhBMP-2 on the surface without any macro- and microcoagulation. Compared with the SLA-treated Ti surface, the amount of coated rhBMP-2 increases up to 63% on the SLA/TIPS-treated Ti surface. As a result, the invitro pre-osteoblast cell response of the SLA/TIPS-treated Ti surface, especially cell adhesion and differentiation behaviors, improves remarkably. A bone-regenerating direct comparison between the rhBMP-2-coated SLA-treated and SLA/TIPS-treated Ti is conducted on a defective dog mandible model. After 8 weeks of implantation surgery, SLA/TIPS-treated Ti with rhBMP-2 exhibits a better degree of contact area for the implanted bone, which mineralizes new bones around the implant. Quantitative results of bone-in-contact ratio and new bone volume also show significantly higher values for the SLA/TIPS-treated Ti with the rhBMP-2 specimen. These results confirm that an SLA/TIPS-treated surface is a suitable rhBMP-2 carrier for a dental implant to achieve early and strong osseointegration of Ti dental implants.

Retrospective clinical study of an implant with a sandblasted, large-grit, acid-etched surface and internal connection: analysis of short-term success rate and marginal bone loss

BackgroundThe purpose of this retrospective study was to evaluate the clinical utility of an implant with a sandblasted, large-grit, acid-etched (SLA) surface and internal connection.MethodsSix patients who received dental implants in the Department of Oral and Maxillofacial Surgery, Chonnam National University Dental Hospital, were analyzed by factors influencing the success rate and marginal bone loss. Factors included patient’s age, sex, implant installation site, whether bone graft was done, type of bone graft materials, approaching method if sinus lift was done, and the size of the fixture. In addition, the marginal bone loss was analyzed by using a radiograph.ResultsAll implants were successful, and the cumulative survival rate was 100 %. Average marginal bone loss of 6 months after the installation was 0.52 mm and 20 months after the functional loading was 1.06 mm. Total marginal bone resorption was 1.58 mm on average. There was no statistically significant difference in mesial and distal marginal bone loss.ConclusionsThe short-term clinical success rate of the implant with an SLA surface and internal connection was satisfactory. Moreover, the marginal bone loss was also consistent with the implant success criteria.

Adhesion of Porphyromonas gingivalis and Tannerella forsythia to dentin and titanium with sandblasted and acid etched surface coated with serum and serum proteins – An in vitro study

ObjectiveTo evaluate the adhesion of selected bacterial strains incl. expression of important virulence factors at dentin and titanium SLA surfaces coated with layers of serum proteins. MethodsDentin- and moderately rough SLA titanium-discs were coated overnight with human serum, or IgG, or human serum albumin (HSA). Thereafter, Porphyromonas gingivalis, Tannerella forsythia, or a six-species mixture were added for 4h and 24h. The number of adhered bacteria (colony forming units; CFU) was determined. Arg-gingipain activity of P. gingivalis and mRNA expressions of P. gingivalis and T. forsythia proteases and T. forsythia protease inhibitor were measured. ResultsCoating specimens never resulted in differences exceeding 1.1 log10 CFU, comparing to controls, irrespective the substrate. Counts of T. forsythia were statistically significantly higher at titanium than dentin, the difference was up to 3.7 log10 CFU after 24h (p=0.002). No statistically significant variation regarding adhesion of the mixed culture was detected between surfaces or among coatings. Arg-gingipain activity of P. gingivalis was associated with log10 CFU but not with the surface or the coating. Titanium negatively influenced mRNA expression of T. forsythia protease inhibitor at 24h (p=0.026 uncoated, p=0.009 with serum). ConclusionsThe present findings indicate that: a) single bacterial species (T. forsythia) can adhere more readily to titanium SLA than to dentin, b) low expression of T. forsythia protease inhibitor may influence the virulence of the species on titanium SLA surfaces in comparison with teeth, and c) surface properties (e.g. material and/or protein layers) do not appear to significantly influence multi-species adhesion.

Biomimetic Approach to Stimulate Osteogenesis on Titanium Implant Surfaces Using Fibronectin Derived Oligopeptide.

Our previous studies demonstrated that a recombinant fibronectin (FN)-derived oligopeptide that we named F20 stimulated osteoblast adhesion, proliferation, and differentiation in vitro and in vivo. In the present study, we used a synthetic oligopeptide and investigated the osteogenic potential of F20 coating on titanium discs, to stimulate superior osseointegration for dental implant surface modification. Surface characteristic analysis of titanium was performed by confocal laser scanning microscopy (CLSM) observation. Synthetic F20 was coated onto the machined or SLA titanium discs by an adsorption procedure. ST2 cells were seeded on the titanium discs. We evaluated cell adhesion with SEM and CLSM observation, cell proliferation with picogreen assay, and osteoblast differentiation with real-time PCR, ALP activity assay, immunoblot assay and ALP staining. FITC-labeled F20 coating on the discs was detected by fluorescence, showing good F20 adsorption and different coating patterns according to the surface roughness. In the SEM and CLSM observations, cells were well attached on the machined surface and greater stress fiber formation was seen on discs coated with F20 than on other discs. F20 stimulated cellular proliferation, as well as osteoblast differentiation through the extracellular signalregulated kinase (Erk) signaling pathway. These cellular responses to F20 were slightly better on the machined titanium surface than the SLA surface. These results suggest that F20 promotes osteogenesis through the Erk pathway and is a suitable biomolecule for surface modification of dental implants for improved osseointegration.

A quantitative method to measure biofilm removal efficiency from complex biomaterial surfaces using SEM and image analysis.

Biofilm accumulation on biomaterial surfaces is a major health concern and significant research efforts are directed towards producing biofilm resistant surfaces and developing biofilm removal techniques. To accurately evaluate biofilm growth and disruption on surfaces, accurate methods which give quantitative information on biofilm area are needed, as current methods are indirect and inaccurate. We demonstrate the use of machine learning algorithms to segment biofilm from scanning electron microscopy images. A case study showing disruption of biofilm from rough dental implant surfaces using cavitation bubbles from an ultrasonic scaler is used to validate the imaging and analysis protocol developed. Streptococcus mutans biofilm was disrupted from sandblasted, acid etched (SLA) Ti discs and polished Ti discs. Significant biofilm removal occurred due to cavitation from ultrasonic scaling (p < 0.001). The mean sensitivity and specificity values for segmentation of the SLA surface images were 0.80 ± 0.18 and 0.62 ± 0.20 respectively and 0.74 ± 0.13 and 0.86 ± 0.09 respectively for polished surfaces. Cavitation has potential to be used as a novel way to clean dental implants. This imaging and analysis method will be of value to other researchers and manufacturers wishing to study biofilm growth and removal.

Effects of low‐frequency ultrasound treatment of titanium surface roughness on osteoblast phenotype and maturation

Low-frequency ultrasound is widely used in the treatment of chronically infected wounds. To investigate its feasibility as a method for insitu restoration of metal implant surfaces in cases of peri-implantitis, we evaluated how low-frequency ultrasound affected surface properties of and response of human osteoblast-like MG63 cells to titanium (Ti). Three Ti surfaces [hydrophobic/smooth (pretreatment, PT); hydrophobic/rough (sandblasted/acid-etched, SLA); and hydrophilic/rough (SLA processed and stored hydrophilicity, mSLA)] were subjected to 25kHz ultrasound for 10min/cm2 . Substrate roughness, chemical composition, and wettability were analyzed before and after ultrasound application. Osteoblastic maturation of cells on sonicated disks was compared to cells on untreated disks. Ultrasound treatment altered the topography of all surfaces. Contact angles were reduced, and chemical compositions were altered by ultrasound on PT and SLA surfaces. Cell response to sonicated PT was comparable to untreated PT. Alkaline phosphatase was increased on sonicated SLA compared to untreated SLA, whereas DNA, osteocalcin, BMP2, osteoprotegerin, and VEGF-A were unchanged. Cells produced less osteocalcin and BMP2 on sonicated mSLA than on untreated mSLA, but no other parameters were affected. These results show that low-frequency ultrasound altered Ti surface properties. Osteoblasts were sensitive to the changes induced by ultrasound treatment. The data suggest that the effect is to delay differentiation, but it is unclear whether this delay will prevent osseointegration. These results suggest that low-frequency ultrasound may be useful for treating implant surfaces insitu leading to successful re-osseointegration of implants affected by peri-implantitis.

Nano modified SLA process for titanium implants

Nano structures gain great prevalence in titanium implants for its enhancement on cell differentiation and gene expression. And sandblast and acid etching (SLA), which yields micro/submicron structures, is the most popular treatment to titanium implants. Aimed at adding nano structures on SLA surfaces, a combination of SLA and H2O2 etching method is proposed. Surface morphology, roughness, surface chemistry and contact angle are characterized. Typical SLA morphology accompanied with nano pits is obtained. Reactive oxygen species are also detected on this surface with remarkable wettability. This novel surface may be promising to dental implants.

Influence of Fixture Thread Exposure on Marginal Bone Level Around Different Implant Systems: A Preliminary Study in Dogs.

To evaluate the influence of implant neck structures on marginal bone loss around intentionally exposed implant fixtures by histomorphometric analysis. Twenty-four implants representing 3 implant systems were placed in three dogs; an implant system with SLA surface without microthreads (group A); one with SLA + calcium surface without microthreads (group B); and one with SLA surface with microthreads (group C). The histomorphometric analyses for vertical defect length (VDL), infrabony defect height (IDH), and defect depth (DD) were performed at the buccal and lingual sides of each fixture. The VDL was lower in group A relative to groups B and C on the buccal and lingual sides. The IDH and DD were higher in group A than group C on the buccal and lingual sides; however, no statistically significant differences were noted between the groups in VDL, IDH, and DD on the buccal and lingual sides of the fixtures. In this preliminary study, marginal bone resorption pattern in the canine mandible varied according to the neck design of each implant fixture. Further studies with larger sample size are needed to confirm the effect of microthreads and surface roughness on the marginal bone loss at the exposed implant fixture.

Effects on the osseointegration of titanium implants incorporating calcium-magnesium: a resonance frequency and histomorphometric analysis in rabbit tibia.

This study assessed the bone formation around titanium surface incorporating the calcium-magnesium (CaMg) deposited by blasted in rabbit tibia bone to determine whether this surface would further enhance bone healing compared with commercially available implant surface. The deposition of CaMg on the titanium SLA surface were obtained by blasting formed the experimental group (EX group), while implants with traditional SLA surface were used as control group (CO group), in this study. Fifty cylindrical threaded implants with a length of 8mm were used (P=25 per group). Five implants of each group were used to surface characterization by scanning electron microscopy, energy dispersive spectrometry, and optical profilometry. Ten New Zealand white rabbits received 40 implants (n=20 per group). Resonance frequency analysis was performed three times (0, 4, and 6weeks). Histomorphometric analysis was performed 4 and 6weeks after implantation. Statistical significance was set at P<0.05. Blasted CaMg deposition on SLA implant surface displayed almost identical surface morphologies and R(a) values at the micron scale. In comparing the implant stability quotient at the three time points, highly significant statistic differences were found (P<0.001). Histomorphological analysis showed higher degrees of bone organization in the samples of test implant surfaces at both implantation times. Within the limitations of this study, the results indicate that the deposition of CaMg on the SLA titanium surface may be effective in enhancing the osseointegration of moderately rough grit-blasted implants by increasing the degree of bone-implant contact.

Nd:YAG laser radiation (1.064nm) accelerates differentiation of osteoblasts to osteocytes on smooth and rough titanium surfaces invitro.

A number of studies revealed beneficial effects of low-level laser therapy (LLLT) regarding cell proliferation and differentiation. To investigate the effect of Nd:YAG (1.064nm) laser radiation in the proliferation and differentiation potential of MG-63 osteoblast-like cells. Additionally, the effects of the surface configurations were to be evaluated. MG-63 osteoblast cells were cultured on different surfaces: plastic tissue culture, smooth (polished) titanium-PT and rough titanium-SLA. The effects of both titanium surfaces and low-level laser therapy (LLLT) on cell adhesion were evaluated by the gene expression of molecules involved in cell proliferation and differentiation. In addition, scanning electron microscopy (SEM) and MTT proliferation assays were used to examine cell morphology and proliferation, respectively. Compared to smooth (PT) surfaces, SLA surfaces favoured MG-63 cell differentiation. Following the application of Nd:YAG laser irradiation, cells yielded statistically significantly improved differentiation on both smooth and SLA surfaces compared with non-irradiated surfaces. The findings of this present study suggest that both surface morphology and Nd:YAG laser irradiation influence the proliferation and differentiation potential of MG-63 cells.

Microscopic Study of Surface Microtopographic Characteristics of Dental Implants.

Objective:To determine and compare the micro topographic characteristics of dental implants submitted to different surface treatments, using scanning electron microscopy (SEM).Materials and Methods:Implants were divided into 7 groups of 3 specimens each, according to the surface treatment used: group 1: Osseotite, BIOMET 3i; group 2: SLA surface, Institut Straumann AG; group 3: Oxalife surface, Tree-Oss implant; group 4: B&W implant surface; group 5: Q-implant surface; group 6: ML implant surface; group 7: RBM surface, Rosterdent implant. The surfaces were examined under SEM (Carl Zeiss FE-SEM-SIGMA). Image Proplus software was used to determine the number and mean diameter of pores per area unit (mm). The data obtained were analyzed with the Mann-Whitney test. A confocal laser microscope (LEXT-OLS4100 Olympus) was used to conduct the comparative study of surface roughness (Ra). Data were analyzed using Tukey's HSD test. Results:The largest average pore diameter calculated in microns was found in group 5 (3.45 µm+/-1.91) while the smallest in group 7 (1.47µm+/-1.29). Significant differences were observed among each one of the groups studied (p<0.05). The largest number of pores/mm2 was found in group 2 (229343) and the smallest number in group 4 (10937). Group 2 showed significant differences regarding the other groups (p<0.05). The greatest roughness (Ra) was observed in group 2 (0.975µm+/-0.115) and the smallest in group 4 (0.304µm+/-0.063). Group 2 was significantly different from the other groups (p<0.05).Conclusion:The micro topography observed in the different groups presented dissimilar and specific features, depending on the chemical treatment used for the surfaces..