Effects of ion beam-assisted deposition of hydroxyapatite on the osseointegration of endosseous implants in rabbit tibiae.

The aim of this study was to evaluate the effects of coating implants with hydroxyapatite (HA) by an ion beam-assisted deposition (IBAD) method and to compare them with implants prepared with sand-blasted and machined surfaces. Examination of osteoblast cultures displayed no difference in the secretion of alkaline phosphatase (ALP) between the various surfaces, but the IBAD-HA specimen showed low ALP secretion (P < .05). Removal torque tests showed that implants coated with HA by the IBAD method had values similar to the implants with a sandblasted surface, but values for the machined-surface implants differed. Implants placed in a group of ovariectomized rabbits showed lower mechanical test values than implants placed in sham-operated rabbits (P < .05). Implants coated with HA by the IBAD method demonstrated the highest mean bone-to-metal contact ratio on all threads and on the 3 best consecutive threads, followed by the implants with a sandblasted surface and implants with a machined surface (P < .05). Hydroxyapatite-coated implants showed a slightly higher bone-to-implant contact ratio than sandblasted implants, but no statistically significant difference was seen between the 2 materials. The implants placed in ovariectomized rabbits showed lower amounts of bone-to-metal contact than the implants placed in sham-operated rabbits, but no statistically significant difference was seen between the 2 groups. Evaluation of bone volume on all threads and the 3 best consecutive threads showed no statistically significant difference among the different surface treatment groups, but lower bone volume was seen in the ovariectomized rabbits than in the sham-operated animals (P < .05).     

Effects of a novel calcium titanate coating on the osseointegration of blasted endosseous implants in rabbit tibiae

OBJECTIVE: The purpose of this study was to investigate the effects of a nanostructured calcium coating on the surfaces of blasted Ti implants on peri-implant bone formation in the rabbit tibiae. MATERIAL AND METHODS: Threaded implants (3.75 mm in diameter, 6 mm in length) were roughened by hydroxyapatite (HA) blasting (control; blasted implants). The implants were then hydrothermally treated in a Ca-containing solution for 24 h to prepare Ca-incorporated Ti surfaces (experimental; blasted/Ca implants). Surface characterizations were performed by scanning electron microscopy and stylus profilometry before and after Ca coating. Forty-two implants (21 control and 21 experimental) were placed in the proximal tibiae of seven New Zealand White rabbits. Each rabbit received six implants. To evaluate the effects of the nanostructured Ca coating on the peri-implant bone-healing response, removal torque tests and histomorphometric analyses were performed 6 weeks after surgery. RESULTS: The Ca coating did not significantly change the surface properties produced by blasting at the micron level. Histologically, active bone apposition was observed in the blasted/Ca implants in the marrow space. Compared with the blasted implants, the blasted/Ca implants showed significantly increased bone-to-implant contact over the total implant length (P<0.01) and greater mean removal torque values (P<0.05). DISCUSSION AND CONCLUSION: The nanostructured, Ca-incorporated surface significantly enhanced the peri-implant bone-healing response of HA-blasted Ti implants. It may be concluded that the use of nanostructured, Ca-coated surfaces may have synergic effects in enhancing osseointegration of blasted Ti implants due to their micron-scaled surface properties and biologically active surface chemistry.     

The effect of chemical and nanotopographical modifications on the early stages of osseointegration

PURPOSE: To investigate the effect of chemically modified implants with similar microtopographies but different nanotopographies on early stages of osseointegration. MATERIALS AND METHODS: Forty screw-shaped implants were placed in 10 New Zealand white rabbits. The implant surface modifications investigated in the present study were (1) blasting with TiO2 and further (2) fluoride treatment or (3) modification with nano-hydroxyapatite. Surface evaluation included topographical analyses with interferometry, morphologic analyses with scanning electron microscopy, and chemical analyses with x-ray photoelectron spectroscopy. Bone response was investigated with the removal torque test, and histologic analyses were carried out after a healing period of 4 weeks. RESULTS: Surface roughness parameters showed a slight decrease of the average height deviation for the fluoride-treated compared to the blasted (control) and nano-hydroxyapatite implants. Scanning electron microscopic images at high magnification indicated the presence of nanostructures on the chemically modified implants. Chemical analyses revealed the presence of titanium, oxygen, carbon, and nitrogen in all implant groups. The blasted-fluoride group revealed fluoride, and the blasted-nano HA group calcium and phosphorus with simultaneous decrease of titanium and oxygen. Removal torque values revealed an increased retention for the chemically modified implants that exhibit specific nanotopography. The histologic analyses demonstrated immature bone formation in contact with the implant surface in all groups, according to the healing period of the experiment. CONCLUSION: Chemical modifications used in the present study were capable of producing a particular nanotopography, and together with the ions present at the implant surface, may explain the increased removal torque values after a healing period of 4 weeks.     

The removal torque of titanium implant inserted in rabbit femur coated with biomimetic deposited Ca-P coating

A number of experimental data on biomimetic deposition CaP (BDCaP) coating implants have reported promising outcomes by histological evaluation. But little is investigated on the role of the BDCaP coating and osseointegration mechanism by interface shear strength. To make a direct biomechanical comparison between the BDCaP coating implants and the uncoated rough titanium implants (control), a well-established animal model for implants removal torque testing was employed in rabbits, using a self-matching experimental design. All implants had an identical cylindrical screw shape without any macroscopic retentive structure. After 2, 4, 6, 8 and 12 weeks of bone healing, removal torque testing was performed to evaluate the interfacial shear strength of each implant type. The torqued implants were sputter-coated with gold for morphology observation and observed with a field-emission electron microscopy. Results showed that the interfacial shear strength of the BDCaP coating implants was similar to that of the uncoated rough implants at 2 and 4 weeks of healing. The mean removal torque values of the BDCaP coating implants were lower than those of control implants (P < 0.05) after 6 weeks of healing. The removal torque values for both types of implants revealed similar mean values after 8 and 12 weeks of healing; there were no significant difference between the two types of implants (P > 0.05). It can be concluded that the BDCaP coating implants had no beneficial effect on the interfacial shear strength at early bone healing stage.     

钛种植体SLA表面HA涂层对骨髓源成骨细胞生物学特性的影响

目的:探讨表面喷砂和酸蚀(SLA)处理后羟基磷灰石(HA)涂层的钛种植体(HA-SLA-Ti),对骨髓源成骨细胞(MOOBs)生物学特性的影响。方法:应用离子束辅助沉积技术(IBAD)在SLA处理的钛种植体(SLA-Ti)表面制备HA涂层,将MOOBs分别接种于HA-SLA-Ti和SLA-Ti表面,观察其生长情况,并对2组MOOBs增殖指数、碱性磷酸酶活性、骨钙素含量以及骨桥蛋白基因(opn)mRNA相对表达量进行比较。结果:MOOBs在HA-SLA-Ti表面生长良好,其细胞增殖指数、碱性磷酸酶活性以及骨钙素含量明显高于SLA-Ti组;且opnmRNA相对表达量是SLA-Ti组的3.25倍。结论:应用IBAD技术在钛种植体SLA表面制备HA涂层,可明显促进MOOBs的增殖及其成骨表型的表达,是一种有应用前景的种植体表面处理方法。     

Histomorphometric analyses of bone interface with titanium-aluminum-vanadium and hydroxyapatite-coated implants by biomimetic process

PURPOSE: The surface properties of dental implants have been considered directly related to the success of the osseointegrated interface. Hydroxyapatite (HA)-coated implants promote a bioactive surface because they facilitate cellular migration and bone growth, resulting in a faster osseointegration. MATERIALS AND METHODS: This study analyzed and compared 2 different implant surfaces: a group composed of titanium implants and another group coated with HA. The HA coating was produced by the biomimetic process to reduce costs. RESULTS AND CONCLUSIONS: After histomorphometric analyses it was possible to demonstrate that there were no statistically significant differences between the groups.     

Primary stability of turned and acid-etched screw-type implants: a removal torque and histomorphometric study in rabbits

PURPOSE: This study evaluated the effect of primary stability on the osseointegration of turned and acid-etched screw implants in a rabbit model. MATERIALS AND METHODS: One pair of turned and acid-etched implants (3.75 in diameter, 5.5 mm long) was placed in each tibia of 15 rabbits. In the right tibial metaphysis the implants were inserted according to a standard surgical protocol. In the left tibia, the osteotomy sites were enlarged using a sequence of drills, and 2 implants were placed with reduction of primary stability. Animals were sacrificed 9 weeks after surgery. Histomorphometric and removal torque analyses were performed to evaluate bone-implant contact and strength of osseointegration. RESULTS: Surface texture had a significant effect on percentage of bone-implant contact (P = .001). Acid-etched implants with high primary stability showed the highest percentage of bone-implant contact (77%), followed by acid-etched implants with low primary stability (61%), turned implants with low primary stability (56%), and turned implants with high primary stability (46%). For removal torque, acid-etched implants had higher peak mean values than turned implant groups (P < .001). Reduction of primary stability was not significant to either percentage of bone-implant contact (P = .645) or removal torque values (P = .214). CONCLUSION: Acid-etched implants had higher bone response and implant fixation than turned implants, regardless of primary stability.     

Effects of a calcium phosphate coating on the osseointegration of endosseous implants in a rabbit model

Objectives: The aim of the present study was to evaluate a Ca–P coated implant surface in a rabbit model. The Ca–P surface (test) was compared to the titanium porous oxide surface (control) in terms of bone‐to‐implant contact (BIC) and removal torque value. Materials and methods: Two hundred and sixteen dental implants were inserted in the tibia and in the femur of 36 rabbits. One hundred and eight were represented by Ca–P oxidized surface implant and other 108 were titanium porous oxide surface modified implants. Each rabbit received six implants. Animals were sacrificed after 2, 4 and 9 weeks of healing. Each group included 12 rabbits. The femoral implant and the proximal implant of the tibia of each animal were subjected to the histologic analysis and the distal implants of the tibia underwent removal torque test (RTQ). Results: Histological analysis in terms of BIC and RTQ did not revealed any significant difference between the Ca–P oxidized surface and the oxidized surface at 2 and 4 weeks. At 9 weeks, the oxidized surface demonstrated better results in terms of RTQ in the tibia. Conclusion: In conclusion, findings from the present study suggested that the Ca–P coating had no beneficial effect in improving bonding strength at the bone–implant interface either at 2, 4 and 9 weeks. To cite this article:
Fontana F, Rocchietta I, Addis A, Schupbach P, Zanotti G, Simion M. Effects of a calcium phosphate coating on the osseointegration of endosseous implants in a rabbit model
Clin. Oral Impl. Res. 22 , 2011; 760–766
doi: 10.1111/j.1600‐0501.2010.02056.x     

Effect of alendronate on endosseous implant integration: an in vivo study in rabbits.

PURPOSE: Alendronate sodium (Fosamax; Merck, Whitehouse Station, NJ) is a second-generation bisphosphonate used widely in osteopenic individuals for decreasing bone resorption and increasing bone density. The ability of alendronate to affect systemic bone remodeling raises natural questions about the drug's influence on dental implant osseointegration. Current knowledge regarding the effect of systemic bisphosphonates, specifically alendronate, on all 3 phrases of osseointegration is incomplete and only a few studies have started to investigate peri-implant bone responses to alendronate-coated implants. The purpose of this study was to determine the effect of systemic alendronate therapy on osseointegration of dental implants based on torque-removal values in rabbits. MATERIALS AND METHODS: Identical titanium dental implants were placed using a standardized surgical protocol in the bilateral distal femur and proximal tibia of 20 New Zealand white rabbits (79 implants total). One week before implant placement, 10 rabbits were given doses of alendronate and continued on weekly dosing for 5 weeks until euthanized. The other 10 rabbits were untreated controls. Torque-removal values were determined using a Tohinichi 15-BTG torque wrench (Tohinichi Mfg Co, Ltd, Tokyo, Japan) for all implants. RESULTS: Analysis of torque data showed no statistical differences between the alendronate and control groups in both femur and tibia sites. A statistically significant difference, however, was noted in torque removal values between femur and tibia sites regardless of drug or non-drug groups. CONCLUSIONS: In summary, orally dosed alendronate administration in rabbits had no significant effect on dental implant torque-removal values 6 weeks after endosseous placement in femur and tibia.     

In vivo evaluation of hydroxyapatite coatings of different crystallinities

PURPOSE: The influence of calcium phosphate (CaP) and hydroxyapatite (HA) crystallinity on bone-implant osseointegration is not well established. In this study, the effect of HA crystallinity and coating method on bone-implant osseointegration was investigated using a rat tibia model. MATERIALS AND METHODS: HA coatings 1 to 5 microm thick were produced using a supersonic particle acceleration (SPA) technology. The HA crystallinities used for this study were weight ratios of 30%, 50%, 70%, and 90%. A total of 128 HA-coated implants were placed into the tibiae of 64 male Sprague-Dawley rats. Bone-implant interfaces were evaluated using histology and push-out strength testing at 3 and 9 weeks after implantation. RESULTS: The 70% crystalline coatings exhibited significantly greater interfacial strength (5 implants/time point/treatment) than the 30%, 50%, and 90% crystalline coatings at 3 and 9 weeks following implantation. The implants with coatings of 70% crystallinity also had the greatest bone contact length. In addition, the HA coatings produced with SPA demonstrated greater interfacial strength and bone contact length than plasma-sprayed HA coatings (except for the HA coating with 30% crystallinity). DISCUSSION: HA coatings of different crystallinities exhibited different dissolution and re-precipitation properties which may enhance early bone formation and bone bonding. CONCLUSIONS: This study suggested that coating crystallinity and coating methods can influence the bone-implant interface.     

The impact of nicotine on osseointegration. An experimental study in the femur and tibia of rabbits

OBJECTIVES: The aim of the present study was to analyze the effect of an enhanced systematic dose of nicotine on osseointegration of titanium implants. MATERIAL AND METHODS: Sixteen female rabbits received either nicotine (n=8) or saline (n=8) administered subcutaneously via mini-osmotic pumps for 2 months. The pump delivered 6 mug/kg/min of nicotine for the animals in the test group. Blood was withdrawn and plasma cotinine levels were measured weekly. Thirty-two titanium implants were inserted into the femur and tibia of all rabbits after 4 weeks and after 6 weeks of nicotine/placebo exposure. Thus, 2- and 4-week healing groups were created. Biomechanical evaluation by (i) resonance frequency analysis test (RFA) on all implants after insertion and before sacrifice and (ii) removal torque test (RMT) on tibial implants before sacrifice was performed. All implants placed in the femur were processed to undecalcified ground sections. The percentage of bone-to-implant contact (BIC) and of bone area within the threads (BD-i) were measured. RESULTS: No significant difference in RMT and RFA values was found between the test and the control group. Histomorphometric measurements of the BIC and the peri-implant BD-i showed no significant differences between the test and the control group after 2 or after 4 weeks. CONCLUSION: Nicotine exposure for a short period of time even in a high dose did not have a significant impact on implant osseointegration in rabbits.     

Early tissue response to modified implant surfaces using back scattered imaging

PURPOSE: It is now well known that implant surface properties affect osseointegration. Grit-blasting with abrasives and coating by plasma are methods to modify implant surfaces. This study aimed to compare the direction of new bone formation associated with three types of surfaces. MATERIALS AND METHODS: Titanium (Ti) alloy rods grit-blasted with alumina abrasive (Group 1, G1), with apatitic abrasive (Group 2, G2), and with apatitic abrasive and plasma-sprayed with hydroxyapatite (Group 3, G3) were implanted in surgically created defects in tibias of New Zealand white rabbits for 2 and 4 weeks. After sacrifice, the implants and surrounding bones were obtained and analyzed using back scattered imaging. RESULTS: Differences in patterns of bone formation among the groups were observed: originating from the cortical bone towards the implant surface (Type A), surrounding the implant (Type B) and originating from the medullary cavity (Type C). G1 and G3 showed Types A and B while G2 exhibited Types A, B and C. After 4 weeks, greater amount of new bone was observed in G2 group compared with those in G1 and G3 groups. CONCLUSIONS: This study demonstrated that patterns of bone formation are influenced by methods of surface modification.     

Oxidized, bioactive implants are rapidly and strongly integrated in bone. Part 1--experimental implants

OBJECTIVES: The study presented was designed to investigate the speed and the strength of osseointegration of oxidized implants at early healing times in comparison which machined, turned implants. MATERIAL AND METHODS: Screw-shaped titanium implants were prepared and divided into two groups: magnesium ion incorporated, oxidized implants (Mg implants, n=10) and machined, turned implants (controls, n=10). Mg implants were prepared using micro-arc oxidation methods. Surface oxide properties of implants such as surface chemistry, oxide thickness, morphology/pore characteristics, crystal structures and roughness were characterized with various surface analytic techniques. Implants were inserted into the tibiae of ten New Zealand white rabbits. After a follow-up period of 3 and 6 weeks, removal torque (RTQ), osseointegration speed (DeltaRTQ/Deltahealing time) and integration strength of implants were measured. Bonding failure analysis of the bone-to-implant interface was performed. RESULTS: The speed the and strength of osseointegration of Mg implants were significantly more rapid and stronger than for turned implants at follow-up periods of 3 and 6 weeks. Bonding failure for Mg implants dominantly occurred within the bone tissue, whereas bonding failure for turned implants mainly occurred at the interface between implant and bone. CONCLUSIONS: Oxidized, bioactive implants are rapidly and strongly integrated in bone. The present results indicate that the rapid and strong integration of oxidized, bioactive Mg implants to bone may encompass immediate/early loading of clinical implants.     

荧光标记法对“脑回形”微弧氧化表面种植体早期骨结合的评价

目的:本文将通过双荧光标记法在兔股骨髁部植入具有“脑回形”(cortex-like)形貌的微弧氧化二氧化钛(TiO2)膜层的种植体,来评价的骨-种植体结合的能力.方法:实验组MAO(cortex-like)为“脑回形”形貌种植体,对照组SLA为具有同等规格的SLA形貌的种植体,共计36颗,通过扫描电镜(SEM)等对材料表面进行表征,随机植入18只新西兰雄性兔的股骨髁部,分别于4w和8w处死取样,处死前第13、14d颈部皮下注射茜素红,处死前第3、4d颈部皮下注射钙黄绿素,通过茜素红-钙黄绿素双色标记示踪检测其矿化速率MAR(mineralization apposition rate).结果:类“脑回形”形貌氧化层由微米级沟槽和纳米级孔洞组成,属超亲水性种植体.4w时间段,实验组MAO组矿化速率MAR(mineralization apposition rate)高于SLA组,但差异无统计学意义(P＞0.05),第8w,MAO与SLA组的MAR值相应的均有所增加,但差异无统计学意义,结论:“脑回形”(cortex-like)形貌的二氧化钛、具有双微层结构膜层,形成与SLA一致的骨结合效果,能早期促进种植体的骨结合,是一种良好的种植体改性方法.     

The influence of cyclosporin a on mechanical retention of dental implants previously integrated to the bone: a study in rabbits

BACKGROUND: Immunosuppressive agents may induce severe changes on bone metabolism and may impair the osseointegration process during the implant healing. No data are available concerning the influence of cyclosporin A on dental implants previously integrated to the bone. The aim of this study was to evaluate the influence of cyclosporin A administration on the mechanical retention of bone previously integrated to dental implants. METHODS: Eighteen female New Zealand rabbits were submitted to an implant surgery. Each animal received one commercial dental implant of 10 x 3.75 mm. After 12 weeks of an undisturbed healing period, six animals were randomly sacrificed and the removal torque test was performed (group A). In addition, six animals were submitted to a daily injection of cyclosporin A in a dosage of 10 mg/kg (group C), and six animals received saline solution as a control (group B). After 12 weeks of cyclosporin A administration, groups B and C were sacrificed and submitted to a removal torque test in which higher values can be interpreted as higher mechanical bone retention to the implant surface or higher osseointegration. RESULTS: The removal torque results were 30.5 (+/-9.8) Ncm for group A, 50.17 (+/-17.5) Ncm for group B, and 26 (+/-7.8) Ncm for group C. The statistical analysis showed significant differences between groups A and B (P <0.05) and groups B and C (P <0.01). CONCLUSION: Cyclosporin A administration may impair the mechanical retention of dental implants previously integrated to the bone.     

Removal torque and histomorphometric investigation of 4 different titanium surfaces: an experimental study in the rabbit tibia

This study presents a histomorphometric and biomechanical comparison of bone response to commercially pure titanium screws with 4 different types of surface topographies placed in the tibial metaphysis of 12 rabbits. Each rabbit had 4 implants placed, 2 in each tibia. The 4 surface topographies were a machined surface, a grit-blasted surface, a plasma-sprayed surface, and an acid-etched (Osseotite) surface. After a healing period of 5 weeks, histomorphometric and removal torque data revealed a significantly higher percentage of bone-to-implant contact and removal torque for acid-etched implants compared to machined, blasted, and plasma-sprayed implants. Within the limits of this short-term experimental study, the results indicated that micro-rough titanium surfaces obtained with acid-etching procedures achieved a 33% greater bone-to-implant contact over machined titanium surfaces with an abutment-type roughness and provided enhanced mechanical interlocking.     

应用IBAD方法制备纯钛表面多孔TCP／HA涂层材料的微观分析

目的:为了改善钛种植体的生物相容性,对纯钛表面沉积多孔磷酸三钙/羟基磷灰石(Tricalciumphosphate/hydroxyapatite,TCP/HA)复合涂层材料的表面结构和化学成分进行分析,并与沉积羟基磷灰石(Hydroxyapatite,HA)的钛表面进行对比。方法:用离子束辅助沉积方法(Ionbeamassisteddeposition,IBAD)在纯钛表面沉积HA和TCP/HA涂层材料,通过扫描电镜(Scanningelectronmicroscope,SEM)、原子力显微镜(Atomicforcemicroscopy,AFM)、X射线能谱分析(EnergydispersiveX-rayanalysis,EDX)以及X射线衍射(X-raydiffraction,XRD)技术,检测两种涂层材料表面的微观形态和化学成分,并进行比较。结果:SEM和AFM显示TCP/HA涂层材料表面存在多孔结构,表面化学成分分析显示TCP/HA涂层的钙磷比低于HA,XRD证实TCP/HA涂层内同时存在TCP和HA两种化合物。结论:用IBAD方法在纯钛表面成功地沉积了具有多孔结构的TCP/HA复合涂层材料,该涂层材料和基体材料的结合牢固,改善了基体材料的生物相容性,是一种有应用前景的种植体表面涂层材料。     

Torsional stability of HA-coated and grit-blasted titanium dental implants.

Hydroxylapatite (HA)-coated and grit-blasted (non-HA-coated) titanium dental implants were inserted into healed extraction sites of canine mandibles. After six weeks, the animals were killed and the implants mechanically tested in torsion to failure. Interface attachment strength, implant/tissue compatibility, integrity of the HA coating, and the location of interface failure were evaluated. Mechanical testing demonstrated an interface torsional strength of 3.98 +/- 0.93 MPa for the HA-coated implants and 2.25 +/- 0.65 MPa for the grit-blasted implants. This represents a 76.9% improvement in the maximum torsional interface strength, and is statistically-significant (p = 0.0004). On qualitative histologic analysis, interface failure was seen to occur primarily at the HA/implant interface, although failure through the HA coating and regions of bone/HA interface failure were observed. The HA-coated implants had bone in direct apposition to their surface with no fibrous tissue interposition. The grit-blasted implants also had regions of direct bone-implant apposition, but these areas were limited to a smaller proportion of the total interface area. There was no evidence of breakdown or change in thickness of the HA coating.     

Osseointegration enhanced by chemical etching of the titanium surface. A torque removal study in the rabbit.

Roughened implant surfaces are thought to enhance osseointegration. Torque removal forces have been used as a biomechanical measure of anchorage or osseointegration in which the greater forces required to remove implants may be interpreted as an increase in the strength of osseointegration. The purpose of this study was to compare the torque resistance to removal of screw shaped titanium implants having an acid etched (HCl/H₂SO₄) surface (Osseotite®) with implants having a machined surface. Two custom screw shaped implants, 1 acid etched and the other machined, were placed into the distal femurs of 10 adult New Zealand White rabbits. These implants were 3.25 mm in diameter x 4.00 mm in length without holes, grooves or slots to resist rotation. Following a 2 month healing period, the implants were removed under reverse torque rotation with a digital torque measuring device. Two implants with the machined surface preparation failed to achieve osseointegration. All other implants were found to be anchored to bone. Resistance to torque removal was found to be 4 x greater for the implants with the acid etched surface as compared to the implants with the machined surface. The mean torque values were 20.50 ± 6.59 N cm and 4.95 ± 1.61 N cm for the acid etched and machined surfaces respectively. The results of this study suggest that chemical etching of the titanium implant surface significantly increases the strength of osseointegration as determined by resistance to reverse torque rotation.     

Effect of bisphosphonates on anodized and heat-treated titanium surfaces: an animal experimental study

Background: Recent investigations reported that osseointegration of titanium implants can be significantly reinforced with a nanostructure treated with anodic oxidation and heat treatment. This experimental study investigates the effect of bisphosphonates on the nanotubular implant surface in rats. Methods: Thirty‐six titanium implants were divided into three groups: 1) machine‐turned (MT), 2) anodized and heat‐treated (AH), and 3) anodized and heat‐ and bisphosphonate‐treated (AHB) groups. The 36 implants were randomly placed in both tibias of 18 male Wistar rats. After 2 and 4 weeks, the levels of osseointegration of the implants were evaluated by a removal torque test and microcomputerized tomography (μCT). Peri‐implant bone tissue on the extracted region was examined for the expression of type I collagen and osteocalcin. Results: The AHB group showed the highest removal torque at 2 and 4 weeks (13.92 ± 1.51 Ncm and 18.10 ± 2.15 Ncm, respectively) followed, in order, by the AH group (11.63 ± 1.58 Ncm at 2 weeks and 14.80 ± 2.34 Ncm at 4 weeks) and MT group (4.30 ± 0.76 Ncm at 2 weeks and 6.20 ± 1.33 Ncm at 4 weeks) with statistically significant differences between the MT and other two groups at both time points. μCT images also revealed a denser appearance around implants in the AHB group than in the other groups. Levels of type I collagen and osteocalcin expression were similar between the MT and AH groups; however, the values were significantly higher in the AHB group compared to the other groups, which were 220.85% ± 71.09% and 363.04% ± 100.21%, respectively (P <0.05). Conclusion: Within the limits of this experiment, it was concluded that surface loading with bisphosphonates significantly improved the degree of osseointegration of titanium implants with a nanostructure.