Acid-etched Titanium Implants Research Articles

Efficacy of plasma treatment for surface cleansing and osseointegration of sandblasted and acid-etched titanium implants.

This study was conducted to evaluate the effects of plasma treatment of sandblasted and acid-etched (SLA) titanium implants on surface cleansing and osseointegration in a beagle model. For morphological analysis and XPS analysis, scanning electron microscope and x-ray photoelectron spectroscopy were used to analyze the surface topography and chemical compositions of implant before and after plasma treatment. For this animal experiment, twelve SLA titanium implants were divided into two groups: a control group (untreated implants) and a plasma group (implants treated with plasma). Each group was randomly located in the mandibular bone of the beagle dog (n = 6). After 8 weeks, the beagle dogs were sacrificed, and volumetric analysis and histometric analysis were performed within the region of interest. In morphological analysis, plasma treatment did not alter the implant surface topography or cause any physical damage. In XPS analysis, the atomic percentage of carbon at the inspection point before the plasma treatment was 34.09%. After the plasma treatment, it was reduced to 18.74%, indicating a 45% reduction in carbon. In volumetric analysis and histometric analysis, the plasma group exhibited relatively higher mean values for new bone volume (NBV), bone to implant contact (BIC), and inter-thread bone density (ITBD) compared to the control group. However, there was no significant difference between the two groups (P > .05). Within the limits of this study, plasma treatment effectively eliminated hydrocarbons without changing the implant surface.

10-year Historical Prospective Cohort Study of Calcium Phosphate-Blasted Acid-Etched Titanium Implants Placed in Different Ridges.

Purpose: To evaluate the survival rate and marginal bone level (MBL) of calcium phosphate-blasted acid-etched titanium implants placed in a cohort of patients with different ridges after a follow-up period of at least 10 years. Materials and Methods: A total of 61 patients with a minimum implant follow-up of 10 years were selected for this historical prospective, best clinical practice cohort study. Between 2009 and 2012, 121 titanium implants were placed using a flap, flapless, or postextractive technique. The implant placement timing was performed according to pre-extractive diagnosis and divided into immediate (immediately after tooth extraction with an absence of infection), early (within 2 to 3 months with an acute periapical lesion), delayed (6 to 12 months from extraction with a large periapical infection), or late (> 12 months from extraction with healed edentulous ridges). All implants were loaded after 3 months with provisional and definitive cemented restorations. Periapical radiographs were taken before implant insertion and at 3, 6, 12, 24, 36, 48, 96, and 120 months (T3, T6, T12, T24, T36, T48, T96, and T120, respectively). The MBL was calculated in single blind by an additional examiner. Linear logistic regression was performed to analyze statistically significant differences in relation to different operative variables at all evaluation times. Multilevel mixed logistic regression was made to evaluate the factors associated to MBL at 10 years (T120). Results: After 10 years, 47 patients and 92 implant restorations were analyzed, showing that 88 implants (95.6%) survived and 4 implants (4.4%) failed. The cumulative drop-out rate was 22.1%. Loosening and/or mobility was observed in a total of 9 abutments (9.7%) during the observational time. No other complications were reported. Implants placed with a flapless technique revealed a similar MBL to those placed with a flap technique. No significant differences were observed between the surgical techniques at T96 and T120. Immediate and early implants revealed a more stable MBL than both delayed and late implants up to T48. At longer evaluation times (T96 and T120), the MBL values were not statistically significant (P > .05). Narrower diameter implants (3.5 mm) revealed a higher bone loss when compared to the 4.1-mm- and 5.0-mm-diameters, especially in the first year from implant insertion (from T3 to T12) and at longer follow-up (T36 and T48). After that, the difference was reduced. Multilevel analysis showed that none of these variables appear to significantly influence MBL at 120 months. Conclusions: MBL was not influenced by surgical technique or implant placement timing after 10 years. Maintaining a strict occlusal and hygiene control created the conditions to preserve bone integrity and achieve a high implant survival rate.

Employing Indirect Adenosine 2A Receptors (A2AR) to Enhance Osseointegration of Titanium Devices: A Pre-Clinical Study.

The present study aimed to evaluate the effect of dipyridamole, an indirect adenosine 2A receptors (A2AR), on the osseointegration of titanium implants in a large, translational pre-clinical model. Sixty tapered, acid-etched titanium implants, treated with four different coatings ((i) Type I Bovine Collagen (control), (ii) 10 μM dipyridamole (DIPY), (iii) 100 μM DIPY, and (iv) 1000 μM DIPY), were inserted in the vertebral bodies of 15 female sheep (weight ~65 kg). Qualitative and quantitative analysis were performed after 3, 6, and 12 weeks in vivo to assess histological features, and percentages of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO). Data was analyzed using a general linear mixed model analysis with time in vivo and coating as fixed factors. Histomorphometric analysis after 3 weeks in vivo revealed higher BIC for DIPY coated implant groups (10 μM (30.42% ± 10.62), 100 μM (36.41% ± 10.62), and 1000 μM (32.46% ± 10.62)) in comparison to the control group (17.99% ± 5.82). Further, significantly higher BAFO was observed for implants augmented with 1000 μM of DIPY (43.84% ± 9.97) compared to the control group (31.89% ± 5.46). At 6 and 12 weeks, no significant differences were observed among groups. Histological analysis evidenced similar osseointegration features and an intramembranous-type healing pattern for all groups. Qualitative observation corroborated the increased presence of woven bone formation in intimate contact with the surface of the implant and within the threads at 3 weeks with increased concentrations of DIPY. Coating the implant surface with dipyridamole yielded a favorable effect with regard to BIC and BAFO at 3 weeks in vivo. These findings suggest a positive effect of DIPY on the early stages of osseointegration.

Effects of a local single dose administration of growth hormone on the osseointegration of titanium implants.

Background The aim of the present study was to evaluate the effect of different concentrations of growth hormone (GH) on endosteal implant’s surface at the early stages of osseointegration.Material and Methods Sixty tapered acid-etched titanium implants were divided into four groups: i) Collagen, used as a control group; and three experimental groups, where after collagen coating, GH was administered directly to the surface in varying concentrations: ii) 0.265 mg, iii) 0.53 mg, and iv) 1 mg. Implants were placed in an interpolated fashion in the anterior flange of C3, C4 or C5 of 15 sheep with minimum distance of 6 mm between implants. After 3-, 6- and 12-weeks of healing samples were harvested, histologically processed, qualitatively and quantitatively assessed for bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO).Results Statistical analysis as a function of time in vivo and coating resulted in no significant differences for BIC and BAFO at any evaluation time point. Histological evaluation demonstrated similar osseointegration features for all groups with woven bone formation at 3 weeks and progressive replacement of woven for lamellar bone in close contact with the implant surface and within the implant’s threads.Conclusions A single local application of growth hormone to the surface of titanium implants did not yield improved implant osseointegration independent of healing time. Key words:Growth hormone, osseointegration, low density bones, metallic implants, sheep, bone-to-implant contact.

Alterations in Surface Roughness and Chemical Characteristics of Sandblasted and Acid-Etched Titanium Implants after Irradiation with Different Diode Lasers

The purpose of this study was to evaluate the effects of diode laser irradiation with different wavelengths on the surface roughness (Ra) and chemical composition of sandblasted and acid-etched (SLA) titanium implants. Three types of diode lasers with different wavelengths were irradiated on the titanium implants at output powers of 1.0, 2.0, and 3.0 W. The mean Ra values for all spots were measured using a scanning probe microscope. Analysis of variance tests were performed to verify the differences in the Ra between groups according to the type of lasers or power out (α = 0.05). For analyzing chemical composition, atomic and weight percent ratios of titanium, oxygen, and carbon were measured using energy-dispersive spectrometry (EDS). The mean Ra of titanium disc was higher in the 3.0-W output than in 1.0-W or 2.0-W output, but there was no statistically significant difference (p > 0.05). In EDS analysis, it was difficult to find a clear difference in the titanium, oxygen, and carbon element ratios between the laser-irradiated and nonirradiated groups. The irradiation of diode laser with 1.0, 2.0, and 3.0 W output for 15 s decontaminated the SLA titanium surface without damage. However, additional clinical trials will be needed to verify the results of the present study.

A laminin-211-derived bioactive peptide promotes the osseointegration of a sandblasted, large-grit, acid-etched titanium implant.

Early implant loading is very important for reducing the duration of missing teeth in human patients. The laminin-derived peptide, DLTIDDSYWYRI motif (Ln2-P3), accelerates bone healing. Therefore, to investigate the hypothesis that Ln2-P3 increases the bone response to sandblasted, large-grit, acid-etched (SLA) titanium implants, the effect of the Ln2-P3 peptide on the osseointegration of SLA titanium implants was evaluated in vitro and in vivo. Human osteoblast-like cells were cultured on untreated, scrambled peptide (SP)-treated, and Ln2-P3-treated SLA titanium discs, and the cellular responses of these cells were evaluated. The Ln2-P3 treatment augmented osteoblast attachment and spreading, alkaline phosphatase activity, and the expression of osteogenic marker genes. Furthermore, the untreated and Ln2-P3-treated SLA titanium implants were inserted into the tibiae of rabbits for 9 and 11 days. Compared with the untreated implants, the Ln2-P3-treated implants showed a significantly higher bone-to-implant contact ratio at Day 9 after implantation and an increased bone area. The Ln2-P3 treatment of the SLA titanium implant surface augmented osteoblastic activity and accelerated peri-implant bone formation at the bone-implant interface. Overall, these results indicated that compared with the SLA titanium surface alone, the Ln2-P3 peptide-treated SLA titanium surface enhances initial osseointegration, thereby facilitating earlier implant loading.

Heat Generation at the Implant-Bone Interface by Insertion of Ceramic and Titanium Implants.

Purpose: The aim of this study is to record material- and surface-dependent heat dissipation during the process of inserting implants into native animal bone. Materials and Methods: Implants made of titanium and zirconium that were identical in macrodesign were inserted under controlled conditions into a bovine rib tempered to 37 °C. The resulting surface temperature was measured on two bone windows by an infrared camera. The results of the six experimental groups, ceramic machined (1), sandblasted (2), and sandblasted and acid-etched surfaces (3) versus titanium implants with the corresponding surfaces (4, 5, and 6) were statistically tested. Results: The average temperature increase, 3 mm subcrestally at ceramic implants, differed with high statistical significance (p = 7.163 × 10−9, resulting from group-adjusted linear mixed-effects model) from titanium. The surface texture of ceramic implants shows a statistical difference between group 3 (15.44 ± 3.63 °C) and group 1 (19.94 ± 3.28 °C) or group 2 (19.39 ± 5.73 °C) surfaces. Within the titanium implants, the temperature changes were similar for all surfaces. Conclusion: Within the limits of an in vitro study, the high temperature rises at ceramic versus titanium implants should be limited by a very slow insertion velocity.

Tapered Screw Implants With Different Machined Neck Designs: A 3-Year Split-Mouth Randomized Controlled Prospective Study.

Tapered Screw Implants With Different Machined Neck Designs: A 3-Year Split-Mouth Randomized Controlled Prospective Study.

LncRNAs Transcriptome Analysis Revealed HIF1A-AS1 as a Mediator of Bone Remodeling Associated with the Micro Structured Titanium Surface

Because of their hierarchical structure, sandblasted and acid etched (SLA) titanium implants are widely used to promote bone apposition. Understanding the molecular mechanisms of SLA titanium implant-enhanced osteogenesis provides clues to improve surface modification methods. However, the epigenetics mechanisms involving SLA surface weren't clear. In this study, we systematically identify the long noncoding RNAs (lncRNAs) and mRNAs related to the superior osseointegration induced by SLA. The mechanical, chemical, and osteogenic characteristics of the fabricated SLA and smooth polished (SMO) titanium surfaces were compared and analyzed. Thousands of lncRNAs and mRNAs within osteogenesis-associated biological processes were differentially expressed in human bone marrow-derived mesenchymal stem cells (hBMSCs) on SLA surface compared with SMO surface. We constructed an mRNA-lncRNA co-expression network to gain insight into the role of differentially expressed lncRNAs and validated the co-expression of HIF1A-AS1/VEGFA, IGF2-AS/GLI2, and HOXD-AS1/FGF10. Further, we identified that the knockdown of HIF1A-AS1 not only decreased the expression of VEGFA, but also significantly inhibited the osteogenic differentiation of hBMSCs. Meanwhile, we found that silencing of lncRNA HIF1A-AS1 reduced the level of phosphorylated mitogen-activated protein kinase (p-MAPK). In conclusion, our study indicated that the SLA surface enhanced osteogenesis partly through differential regulation of lncRNAs, like HIF1A-AS1. Our study also increased the understanding of the role lncRNA HIF1A-AS1 in the differentiation of osteoblast, providing clues for the potential optimization of titanium implant surface.

Ligature-Induced Peri-implant Bone Loss Around Loaded Zirconia and Titanium Implants.

To radiographically investigate ligature-induced peri-implant bone loss around loaded titanium (Ti-SLA) and zirconia (ZrO2-ZLA) implants using a canine model. Forty sandblasted and acid-etched titanium and zirconia implants were alternately placed in the mandibles of five canines (20 Ti-SLA, 20 ZrO2-ZLA). Implants were restored after 6 weeks of unloaded healing. After 4 weeks of functional loading, oral hygiene procedures were stopped and experimental peri-implant bone loss was initiated by placing cotton ligatures. After 8 weeks of active progression, ligatures were removed and plaque was allowed to accumulate for another 16 weeks of spontaneous progression (without ligatures). Standardized radiographs were taken at implant placement, at functional loading, and every 2 weeks during active and spontaneous progression of bone loss. Before ligature placement, all implants were successfully osseointegrated and no clinical or radiographic signs of peri-implant infections were detectable. Two weeks after ligature removal, one titanium implant was lost; however, no zirconia implant failures were observed during the study. Radiographically, zirconia implants revealed statistically significantly less crestal peri-implant bone loss compared to titanium implants at the end of the active progression period (Ti-SLA: 3.92 mm; ZrO2-ZLA: 2.65 mm; P < .01); however, no significant differences occurred after the spontaneous progression period (P = .6). Combining the active and spontaneous progression periods together, zirconia implants demonstrated significantly reduced peri-implant bone loss compared to titanium implants (Ti-SLA: 3.76 mm; ZrO2-ZLA: 2.42 mm; P < .01). These results demonstrate a significantly reduced ligature-induced inflammation and bone loss for ZrO2-ZLA implants compared to Ti-SLA implants in the canine model.

Effect of the Wnt signal-RANKL/OPG axis on the enhanced osteogenic integration of a lithium incorporated surface.

Bone remolding involves the formation of new bone by osteoblasts and the absorption of old bones by osteoclasts. Due to the vital role of osteoblasts and osteoclasts during bone regeneration, it might be feasible to promote osseointegration around the titanium implants by stimulating osteoblasts and inhibiting osteoclasts by modifying the surfaces of the implants. Lithium is used in the treatment of psychiatric patients, and it may be associated with osteogenesis. In this study, lithium was incorporated with sandblasted, large-grit and acid-etched titanium implants via a hydrothermal treatment. In vitro, the nano-scale surface enhanced the adhesion and proliferation of bone marrow mesenchymal stem cells (BMSCs). Moreover, the SLA-Li surface displayed a negative effect on the process of osteoclastogenesis. Further mechanism analysis indicated that the canonical Wnt/β-catenin signaling pathway was activated according to the results of RT-PCR and western blotting. More importantly, the RANKL/OPG signaling axis was also involved in these effects on the SLA-Li surface. The experiments in vivo proved that the SLA-Li surface could induce the bone formation and osseointegration during the early osseointegration after the dental implant surgery. These results suggested that bone homeostasis could be manipulated by an SLA-Li surface, which implied that this new surface might serve as a promising material for clinical application in the future.

Effect of Plasma Oxidation-Treated TiOx Film on Early Osseointegration.

To develop a TiOx film with high wettability using plasma oxidation methodology and to evaluate the effect of such surface modification on new bone formation and early osseointegration. Twenty sandblasted and acid-etched (SLA) titanium implants layered with a TiOx film layer were modified by plasma oxidation using a Radio Frequency Plasma Enhanced Chemical Vapor Deposition (RFPECVD) system. Twenty SLA implants without any treatment were employed as the control group. Scanning electron microscopy was used to evaluate surface morphology of the coating. X-ray photoelectron spectroscopy (XPS) was utilized to identify the chemical composition of the implant surface, and the wettability was tested with the help of the contact angle calculation. All implants were randomly inserted into the proximal tibia of 20 rats with a split-plot design. Four weeks after implantation, early osseointegration of the two groups was analyzed by a removal torque test and histologic analysis. The surface characteristics showed that both SLA and plasma oxidization-treated SLA (PO-SLA) surfaces displayed similar typical isotropic irregular indentations. As revealed by the XPS analyses, both TiO2 and Ti2O3 were coexistent in the PO-SLA surface. The contact angle measurement revealed that the super-hydrophilic surface was created out in the PO-SLA surface. Four weeks after implantation, a higher removal torque value was observed in the group of implants with the PO-SLA surface compared with the control group (12.68 ± 1.07 vs 9.95 ± 1.42 Ncm, P < .05), and a higher rate of bone-to-implant contact was also detected in the same group of implants with the PO-SLA surface (47.79% ± 9.59% vs 39.41% ± 9.00%, P < .05). The bone area ratio was also higher in the PO-SLA surface group than the control group (39.10% ± 10.01% vs 29.01% ± 7.24%, P < .05). It was indicated that the PO-SLA surface has combined the effect of high wettability and micro/nano-structures to notably increase early bone apposition.

Evaluation of the osseointegration of dental implants coated with calcium carbonate: an animal study

In an attempt to overcome the limitations of titanium in dental and orthopaedic clinical applications, a new method has been developed to prepare calcium carbonate coatings on sandblasted and acid-etched (SA) titanium implants. The purpose of this study was to investigate the effect of calcium carbonate-SA (CC-SA) implants on osseointegration in vivo. The surfaces of SA and CC-SA implants were characterised for surface morphology and surface chemistry. Subsequently, these two kinds of implants were implanted in the femoral condyles of rabbits. The implants were retrieved and prepared for histological and histomorphometric evaluation 1, 2, 4, 8 and 12 weeks after implantation. Significantly higher values of bone-to-implant contact of the entire implant except the gap area (BIC_ALL) and the bone-to-implant contact of the gap area (BIC_GAP) were found in animals with the CC-SA implants than in those with the SA implants at 4 weeks. Higher values of total gap bone were found in those with the CC-SA implants than in those with the SA implants at 1, 2 and 4 weeks. In conclusion, the current findings demonstrate that the calcium carbonate coating can improve and accelerate the early ingrowth of bone and osseointegration at the early healing phase. This may reduce clinical healing times and thus improve implant success rates.

Chemotherapeutic decontamination of dental implants colonized by mature multispecies oral biofilm.

No studies have tested disinfectants on mature multispecies oral biofilms on titanium substrata. The aim of this study was to investigate the efficacy of commonly used antimicrobial agents in decontamination of multispecies mature oral biofilm on sandblasted, large-grit, acid-etched (SLA) titanium implants. SLA titanium disks were inoculated with dental plaque and cultured anaerobically for 21days. The disks were rinsed with 0.9% NaCl, exposed for 2min. to tetracycline paste, 1% Chlorhexidine gel (CHX), 35% phosphoric acid gel (Etch) or a novel chemical formula (0.3% cetrimide, 0.1% CHX and 0.5% EDTA) and then rinsed again with 0.9% NaCl. Bacteria were quantified from scanning electron micrographs of the implant surfaces. Living bacteria were quantified with confocal laser scanning microscopy (CLSM). Rinsing the surfaces with 0.9% NaCl removed the majority of the biofilm. However, bacteria persisted in all specimens and none of the disinfectants was superior to the double saline rinse group. CLSM analysis showed that CHX and Etch groups had a statistically significant reduction of viable bacteria, although small. Overall the results show that many disinfection agents used in the clinic are ineffective in biofilm removal and leave live bacteria on the surface.

Success rate and strength of osseointegration of immediately loaded UV-photofunctionalized implants in a rat model

Statement of problemDespite its clinical benefits, the immediate loading protocol might have a higher risk of implant failure than the regular protocol. Ultraviolet (UV) photofunctionalization is a novel surface enhancement technique for dental implants. However, the effect of photofunctionalization under loading conditions is unclear. PurposeThe purpose of this animal study was to evaluate the effect of photofunctionalization on the biomechanical quality and strength of osseointegration under loaded conditions in a rat model. Material and methodsUntreated and photofunctionalized, acid-etched titanium implants were placed into rat femurs. The implants were immediately loaded with 0.46 N of constant lateral force. The implant positions were evaluated after 2 weeks of healing. The strength of osseointegration was evaluated by measuring the bone-implant interfacial breakdown point during biomechanical push-in testing. ResultsPhotofunctionalization induced hydrophilic surfaces on the implants. Osseointegration was successful in 28.6% of untreated implants and 100% of photofunctionalized implants. The strength of osseointegration in successful implants was 2.4 times higher in photofunctionalized implants than in untreated implants. The degree of tilt of untreated implants toward the origin of force was twice that of photofunctionalized implants. ConclusionsWithin the limit of an animal model, photofunctionalization significantly increased the success of osseointegration and prevented implant tilt. Even for the implants that underwent successful osseointegration, the strength of osseointegration was significantly higher for photofunctionalized implants than for untreated implants. Further experiments are warranted to determine the effectiveness of photofunctionalization on immediately loaded dental implants.

Bone Morphogenetic Protein-2 Hybridized with Nano-Anchored Oligonucleotides on Titanium Implants Enhances Osteogenic Differentiation In Vivo.

Previous in vitro studies have shown that DNA oligonucleotides (ODN) can be successfully used as anchor strands for the binding and retarded release of biologically active recombinant human bone morphogenetic protein 2 (rhBMP-2). The aim of the present study was to test the hypothesis that rhBMP-2 bound to the surface of titanium implants through hybridization with nano-anchored ODN strands is biologically active and can enhance the induction of osteogenic markers in peri-implant bone in vivo. Custom-made, surface acid-etched (SAE) titanium discs and implants were coated with ODN anchor strands and subsequently hybridized with complementary ODN strands conjugated to rhBMP-2 (AS_CS_BMP-2). Discs/implants with SAE surface, ODN-coated surface (AS), and ODN-coated surface with nonconjugated rhBMP-2 (AS_BMP-2) served as controls. Release of rhBMP-2 from the coated discs was evaluated in vitro using enzyme-linked immunosorbent assay (ELISA), and bone-specific activity was assessed through pNPP turnover by induced alkaline phosphatase (AP) up to a period of 56 days. In vivo expression of bone-specific markers was analyzed after bilateral placement of coated implants into the tibiae of 36 Wistar rats (72 tibiae total). Immunostaining for AP and runt-related transcription factor 2 (Runx2) was carried out after 1, 4, and 13 weeks. Release from the AS_CS_ BMP-2-coated titanium surfaces was significantly retarded compared to surfaces loaded with AS_BMP-2. The in vitro biologic activity of the released rhBMP-2 conjugates measured by AP induction was equivalent to released nonconjugated rhBMP-2. Immunostaining revealed a significant increase in the in vivo induction of AP around AS_CS_BMP-2 implants compared to the controls after 1 and 4 weeks. Titanium AS_CS_BMP-2 implants can significantly enhance osteogenic differentiation in vivo in peri-implant bone in early periods of osseointegration.

Direct communication between osteocytes and acid-etched titanium implants with a sub-micron topography.

The osteocyte network, through the numerous dendritic processes of osteocytes, is responsible for sensing mechanical loading and orchestrates adaptive bone remodelling by communicating with both the osteoclasts and the osteoblasts. The osteocyte network in the vicinity of implant surfaces provides insight into the bone healing process around metallic implants. Here, we investigate whether osteocytes are able to make an intimate contact with topologically modified, but micrometre smooth (S a < 0.5 µm) implant surfaces, and if sub-micron topography alters the composition of the interfacial tissue. Screw shaped, commercially pure (cp-Ti) titanium implants with (i) machined (S a = ~0.2 µm), and (ii) two-step acid-etched (HF/HNO3 and H2SO4/HCl; S a = ~0.5 µm) surfaces were inserted in Sprague Dawley rat tibia and followed for 28 days. Both surfaces showed similar bone area, while the bone-implant contact was 73 % higher for the acid-etched surface. By resin cast etching, osteocytes were observed to maintain a direct intimate contact with the acid-etched surface. Although well mineralised, the interfacial tissue showed lower Ca/P and apatite-to-collagen ratios at the acid-etched surface, while mineral crystallinity and the carbonate-to-phosphate ratios were comparable for both implant surfaces. The interfacial tissue composition may therefore vary with changes in implant surface topography, independently of the amount of bone formed. Implant surfaces that influence bone to have higher amounts of organic matrix without affecting the crystallinity or the carbonate content of the mineral phase presumably result in a more resilient interfacial tissue, better able to resist crack development during functional loading than densely mineralised bone.

Vertical bone augmentation induced by ultrathin hydroxyapatite sputtered coated mini titanium implants in a rabbit calvaria model.

The purpose of this study was to evaluate the vertical new bone formation induced by sputtered HA-coated titanium implants (HA-coated) compared with sandblasted acid-etched titanium implants (noncoated) in a rabbit calvarial model. Twenty HA-coated and 20 noncoated titanium implants were divided equally into four groups as HA-coated implant (HA); noncoated implant (NC); HA-coated implant with membrane (HA/M); noncoated implant with membrane (NC/M). All implants were placed 5 mm above the original bone (OB). Collagen membranes were placed over the implants in HA/M and NC/M groups. The animals were sacrificed at 4 weeks (n = 5) and 8 weeks (n = 5). Vertical bone height above OB (VBH, mm) and augmented bone area (ABA, mm(2) ) were analyzed histologically and radiographically. At 4 weeks, VBH reached significantly higher level in HA/M group compared with other three groups (p < 0.05). At 8 weeks, significant difference was detected between HA/M and NC groups (p < 0.05). At 4 and 8 weeks, ABA in HA/M group was significantly larger compared with other three groups (p < 0.05). The present results indicated that sputtered HA-coated titanium implant together with collagen membrane could be a novel and effective approach for vertical bone augmentation.

Instrumentation With Ultrasonic Scalers Facilitates Cleaning of the Sandblasted and Acid-Etched Titanium Implants

Mechanical instrumentation is widely used to debride dental implants, but this may alter the surface properties of titanium, which in turn may influence bacterial adhesion and make it more difficult to remove the biofilm. This in vitro study was performed (1) to assess the amount of biofilm formation on a sand-blasted and acid-etched titanium fixture treated with ultrasonic scalers with metal, plastic, and carbon tips and (2) to evaluate how this treatment of titanium surfaces affects implant cleaning by brushing with dentifrice. The titanium fixtures were treated with various ultrasonic scaler tips, and surface roughness parameters were measured by confocal microscopy. Biofilm was formed on the treated fixtures by using pooled saliva from 10 subjects, and the quantity of the adherent bacteria was compared with crystal violet assay. The fixture surfaces with biofilm were brushed for total of 30 seconds with a toothbrush with dentifrice. The bacteria remaining on the brushed fixture surfaces were quantified by scanning electron microscopy. Surface changes were evident, and the changes of the surfaces were more discernible when metal tips were used. A statistically significant decrease in roughness value (arithmetic mean height of the surface) was seen in the 2 metal-tip groups and the single plastic-tip group. After brushing with dentifrice, the treated surfaces in all the treatment groups showed significantly fewer bacteria compared with the untreated surfaces in the control group, and the parts of the surfaces left untreated in the test groups. Within the limits of this study, treatment of titanium fixture surfaces with ultrasonic metal, plastic, or carbon tips significantly enhanced the bacterial removal efficacy of brushing. Thorough instrumentation that smooths the whole exposed surface may facilitate maintenance of the implants.

Evaluation of bone healing on sandblasted and Acid etched implants coated with nanocrystalline hydroxyapatite: an in vivo study in rabbit femur.

This study aimed at investigating if a coating of hydroxyapatite nanocrystals would enhance bone healing over time in trabecular bone. Sandblasted and acid etched titanium implants with and without a submicron thick coat of hydroxyapatite nanocrystals (nano-HA) were implanted in rabbit femur with healing times of 2, 4, and 9 weeks. Removal torque analyses and histological evaluations were performed. The torque analysis did not show any significant differences between the implants at any healing time. The control implant showed a tendency of more newly formed bone after 4 weeks of healing and significantly higher bone area values after 9 weeks of healing. According to the results from this present study, both control and nano-HA surfaces were biocompatible and osteoconductive. A submicron thick coating of hydroxyapatite nanocrystals deposited onto blasted and acid etched screw shaped titanium implants did not enhance bone healing, as compared to blasted and etched control implants when placed in trabecular bone.