Influence of the local application of sodium alendronate gel on osseointegration of titanium implants

Can locally applied risedronate be an effective agent when combined with xenografts? An animal study

BACKGROUND

To examine the effects of local risedronate application with xenografts on healing of rabbit skull defects using histological, histomorphometric, immunohistochemical, and three-dimensional radiological methods.

METHODS

Two critical-sized defects with a diameter of 10 mm were created in 16 rabbits and filled with xenogenic bone graft and xenogenic bone graft + 5 mg risedronate in the control I and risedronate (RIS) groups, respectively. Residual graft, new bone, soft tissue areas, and bone volume were evaluated in the 4- and 8-week study groups.

RESULTS

In both the 4- and 8-week samples, the RIS group samples had significantly higher mean new bone area values than the C group (p < 0.05). In both groups, the values for the new bone area were significantly higher in the 8-week-old samples than in the 4-week-old samples (p < 0.05). The h scores obtained for sialoprotein and osteopontin did not differ significantly between the groups at either time point (p > 0.05). The results of radiological evaluation showed that the bone density value was significantly higher in the C group than in the RIS group at either time point (p < 0.05).

CONCLUSIONS

Although this study aimed to demonstrate the effect of risedronate on the osteoconductive properties of xenografts when applied locally, targeted results could not be achieved.

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 (A_2AR), 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.

The impact of medication on osseointegration and implant anchorage in bone determined using removal torque-A review

Permanently anchored metal implants are frequently used in dental, craniomaxillofacial, and orthopaedic rehabilitation. The success of such therapies is owed to the phenomenon of osseointegration—the direct connection between the living bone and the implant. The extent of biomechanical anchorage (i.e., physical interlocking between the implant and bone) can be assessed with removal torque (RTQ) measurement. Implant anchorage is strongly influenced by underlying bone quality, involving physicochemical and biological properties such as composition and structural organisation of extracellular matrix, extent of micro-damage, and bone turnover. In this review, we evaluated the impact of various pharmacological agents on osseointegration, from animal experiments conducting RTQ measurements. In addition to substances whose antiresorptive and/or anti-catabolic effects on bone are well-documented (e.g., alendronate, zoledronate, ibandronate, raloxifene, human parathyroid hormone, odanacatib, and the sclerostin monoclonal antibody), positive effects on RTQ have been reported for substances that do not primarily target bone (e.g., aminoguanidine, insulin, losartan, simvastatin, bone morphogenetic protein, alpha-tocopherol, and the combination of silk fibroin powder and platelet-rich fibrin). On the contrary, several substances (e.g., prednisolone, cyclosporin A, cisplatin, and enamel matrix derivative) tend to adversely impact RTQ. While morphometric parameters such as bone-implant contact appear to influence the biomechanical anchorage, increased or decreased RTQ is not always accompanied by corresponding fluctuations in bone-implant contact. This further confirms that factors such as bone quality underpin biomechanical anchorage of metal implants. Several fundamental questions on drug metabolism and bioavailability, drug dosage, animal-to-human translation, and the consequences of treatment interruption remain yet unanswered.

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Effects of pharmacological agents on osseointegration of metal implants are reviewed.

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Removal torque is considered as an objective measure of osseointegration.

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Most investigated anabolic agents are alendronate, zoledronate, and ibandronate.

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hPTH has a positive effect while cyclosporin A and cisplatin have negative effects.

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Correction of underlying systemic disorders leads to improved osseointegration.

The Effects of Local Alendronate With or Without Recombinant Human Bone Morphogenetic Protein 2 on Dental Implant Stability and Marginal Bone Level: A Randomized Controlled Study

ABSTRACT

The aim of this study was to evaluate the effects of local application of bisphosphonate gel and recombinant human bone morphogenic protein 2 gel, on titanium dental implant stability and marginal bone level. Twenty-seven patients with upper and lower missing posterior tooth/teeth were included in the study with a total of 71 implants that were used for rehabilitation. The implants were randomly divided into 4 groups: 3 study groups and 1 control. Group1; local application of bisphosphonate gel, group 2; local application of recombinant human bone morphogenic protein 2 gel, group 3; local application of a mixed formula of both gels. The gel application was immediately preimplant insertion, group 4; implant insertion without application of any medication. Using resonance frequency analyzer, implant stability was measured 4 times; primary, 8 weeks (second stage surgery), 12 weeks, and at least 14 weeks post functional loading. The level of the marginal bone around each implant were assessed using cone beam computed tomography. Four implants failed. Generally, there was a similar pattern of changes in implant stability over the study period in all groups and the stability was dependent on the healing time with no significant difference between groups. There was no significant treatment effect regarding marginal bone level differences of study groups against control, although there were significant differences on palatal and mesiodistal surfaces among the study (test) groups.

Local application of the osteogenic inducer sustained-release system promotes early bone remodeling around titanium implants

Enhanced osseointegration and a shortened healing time are required for dental implant treatment. The aim of this study was to evaluate whether topical application of the osteogenic inducer (OI) sustained-release system over the implant promotes early bone remodeling around the implant. The mandibular canines of 15 New Zealand White rabbits were extracted. After 3 months of healing, implants coated with poly(lactic-co-glycolic acid) (PLGA)+OI, PLGA alone, or no material (control) were inserted into the canine sites. After 4 weeks, specimens were harvested from the three groups and evaluated. Implant stability recorded by Periotest revealed significantly higher values for the PLGA + OI group (-2.61 ± 0.43) than for the PLGA (-1.47 ± 0.45) and control groups (-1.08 ± 0.19) (P < 0.001). Moreover, the PLGA+OI group had improved bone volume and structural parameters around the implants at 4 weeks, as shown by significantly increased BV/TV, BSA/BV, Tb.Th, and BIC (P < 0.05), as well as decreased Tb.Sp (P = 0.010) compared with the other groups. The histological results showed more trabecular bone and bone matrix around the implants in the PLGA+OI group. Therefore, local application of the OI sustained-release system might be able to promote early bone remodeling around titanium implants and facilitate faster and better osseointegration.

Long-term evaluation of alendronate treatment on the healing of calvaria bone defects in rats. Biochemical, histological and immunohistochemical analyses

OBJECTIVE

The aim of this study was to investigate the effects of the long-term alendronate administration on bone healing in defects created in rat calvarias.

MATERIALS AND METHODS

Female Wistar rats were randomly distributed into 2 groups: Control (CTL): animals received saline solution once a week; and Alendronate (ALD): rats underwent alendronate treatment (1 mg/kg/weekly). After 120 days from the commencement of treatment, a critical size defect was created in all animals, and 10 animals from each group were sacrificed at 5, 10, 15, 20, 25, 30, 45 and 60-days after the defect creation. On the day of sacrifice, urine and blood samples were collected for determination of the serum levels of bone resorption and formation markers by enzyme linked immunosorbent assay, and the urinary concentration of deoxypyridinoline. Bone mineral density (BMD) in the femurs, descriptive histology, tartrate-resistant acid-phosphatase staining and immunohistochemical analyzes were assessed in the calvaria.

RESULTS

Alendronate group showed increased BMD compared to the test group. The concentration of C-terminal telopeptide of type I collagen and deoxypyridinoline decreased significantly, and the concentration of aminoterminal propeptide of procollagen type 1 and osteocalcin were significant lower in the alendronate group. Immunohistochemical analysis showed significant downregulation in the inducible nitric oxide synthase, runt-related transcription factor-2, cathepsin-K and receptor activator of nuclear factor kappa-B ligand expression in the alendronate group. Vascular endothelial growth factor and osteopontin were upregulated in the later periods of alendronate group.

CONCLUSIONS

Our results suggest that long-term treatment with alendronate did not compromise the repair processing of critical size defects in rat.

Ibandronate Treatment Before and After Implant Insertion Impairs Osseointegration in Aged Rats with Ovariectomy Induced Osteoporosis

Excessive decreases in bone volume (BV) and bone mineral density (BMD) can lead to osteoporosis, potentially hindering implant osseointegration. Bisphosphonates are commonly used to combat osteoporosis by slowing osteoclast-mediated resorption; however, functional osteoclasts are integral to bone remodeling and, thus, implant osseointegration, potentially contraindicating bisphosphonate use during implantation. To optimize the use of implant technologies in patients with compromised bone structure and metabolism, we need a more complete understanding of the biological response to surface design. The goal of this study was to assess the effects of osteoporosis and bisphosphonates on osseointegration of titanium (Ti) implants with microstructured surfaces, which have been shown to support osteoblast differentiation in vitro and rapid osseointegration in vivo. Forty, 8-month-old, virgin, female CD Sprague Dawley rats underwent ovariectomy (OVX) or sham (SHOVX) surgery. After 5 weeks, animals were injected subcutaneously with either the bisphosphonate (BIS), Ibandronate (25 µg/kg), or phosphate-buffered saline (PBS) every 25 days. 1 week after the initial injection, Ø2.5mm × 3.5mm microrough (SLA; grit-blasted/acid etched) implants were placed transcortically in the distal metaphysis of each femur resulting in four groups: 1) SHOVX+PBS; 2) SHOVX+BIS; 3) OVX+PBS; and 4) OVX+BIS. After 28d, qualitative properties of the bone and implant osseointegration were assessed using micro-computed tomography (microCT), calcified histomorphometry (Van Gieson's stain), and removal torque testing. microCT revealed decreased bone volume in OVX rats, which was slowed by bisphosphonate treatment. Reduced bone-to-implant contact (BIC) was evident in OVX+PBS compared to SHOVX+PBS. Although BV/TV was increased in OVX+BIS compared to OVX+PBS, bisphosphonate treatment had no effect on BIC. Removal torque testing revealed a higher maximum torque, torsional stiffness, and torsional energy in SHOVX compared to OVX with no effects due to bisphosphonate treatment. Our results show that osseointegration is decreased in osteoporotic animals. Ibandronate halts the progression of osteoporosis but does not enhance osseointegration. © 2019 The Authors. JBMR Plus Published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Impact of bisphosphonate therapy on dental implant outcomes: An overview of systematic review evidence

The purpose of this overview was to assess the methods, quality, and outcomes of systematic reviews conducted to evaluate the impact of bisphosphonates on dental implants and the risk of developing bisphosphonate-related osteonecrosis of the jaw after dental implant surgery. An electronic search without date or language restriction was performed in the PubMed/MEDLINE, Cochrane CENTRAL, Web of Science, and LILACS databases (to January 2018). Eligibility criteria included systematic reviews that evaluated the impact of bisphosphonates on implant outcomes. The quality assessment of the included reviews was done using AMSTAR 2 guidelines. The protocol of this overview was registered in PROSPERO (CRD42018089617). The search and selection process yielded seven reviews, published between 2009 and 2017. None of the systematic reviews included in this study obtained the maximum score in the quality assessment. The scientific evidence available demonstrates that patients with a history of bisphosphonate use do not present a higher risk of dental implant failure or marginal bone loss compared to patients who have not used bisphosphonates. The literature also suggests that patients who undergo surgical trauma during the installation of dental implants may be more susceptible to bisphosphonate-related osteonecrosis of the jaw.

Local delivery of a zoledronate solution improves osseointegration of titanium implants in a rat distal femur model

This study aimed to determine whether locally applied anti-resorptive agents acetazolamide or zoledronic acid would improve mechanical stability in implant osseointegration when applied as a solution within the medullary canal. Thirty-three rats received titanium-implants bilaterally in their intramedullary femoral canals. Prior to implantation, animals received 0.1 ml saline, 1 mM acetazolamide solution, or 0.7 mM zoledronic acid solution directly into the medullary cavity. The control group only received saline within the medullary canal while the treatment groups only received the respective treatment to which they were randomized. Animals were allowed to heal 4 weeks, at which time they were euthanized and femurs isolated for mechanical and radiographic evaluation. Push-out force to failure increased 152% in the zoledronic acid group relative to the control. There was no significant difference in push-out force with acetazolamide relative to control. Also, zoledronic acid increased metaphyseal bone volume fraction 46% and increased metaphyseal bone-implant contact 58% relative to the control. Recent research exploring local injection of medications to improve implant osseointegration and minimize systemic-effects has failed to quantitatively evaluate implant fixation strength on non-hydroxyapatite coated implants or implants without previous bone compaction. This study demonstrated that a simple injection of zoledronic acid into the medullary canal, rather than coatings or commercial gels, can increase fixation strength of an uncoated titanium-implant. Our findings indicate simple injection of zoledronic acid in saline solution has the potential for improving fixation of uncemented joint implants. Clinical Significance: Intramedullary injection of local bisphosphonate solutions could be implemented to improve osseointegration in cementless arthroplasty. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3294-3298, 2018.

Antiosteoporotic Drugs to Promote Bone Regeneration Related to Titanium Implants: A Systematic Review and Meta-Analysis

IMPACT STATEMENT

This meta-analysis was to investigate literature on the administration of antiosteoporotic drugs as an effective adjunct therapy for implant osseointegration using in vivo animal models.

A new synthetic granular calcium phosphate compound induces new bone in a sinus lift rabbit model

OBJECTIVES

The aim of this study was to investigate if a synthetic granular calcium phosphate compound (CPC) and a composite bisphosphonate-linked hyaluronic acid-calcium phosphate hydrogel (HABP·CaP) induced similar or more amount of bone as bovine mineral in a modified sinus lift rabbit model.

MATERIAL AND METHODS

Eighteen adult male New Zeeland White rabbits, received randomly one of the two test materials on a random side of the face, and bovine mineral as control on the contralateral side. In a sinus lift, the sinus mucosa was elevated and a titanium mini-implant was placed in the alveolar bone. Augmentation material (CPC, HABP·CaP or bovine bone) was applied in the space around the implant. The rabbits were euthanized three months after surgery and qualitative and histomorphometric evaluation were conducted. Histomorphometric evaluation included three different regions of interest (ROIs) and the bone to implant contact on each installed implant.

RESULTS

Qualitative assessment (p = <.05), histomorphometric evaluations (p = < .01), and implant incorporation (p = <.05) showed that CPC and bovine mineral induced similar amount of bone and more than the HABP·CaP hydrogel.

CONCLUSION

CPC induced similar amount of bone as bovine mineral and both materials induced more bone than HABP·CaP hydrogel.

CLINICAL SIGNIFICANCE

The CPC is suggested as a synthetic alternative for augmentations in the maxillofacial area.

Pretreatment with Bisphosphonate Enhances Osteogenesis of Bone Marrow Mesenchymal Stem Cells

Mesenchymal stem cell (MSC)-mediated bone regeneration is used to replace lost bone. However, methods to accelerate the process and stabilize regenerated bone remain limited. Therefore, we investigated the effect of bisphosphonates (BPs) on the function of bone marrow mesenchymal stem cells (BMMSCs) to determine if they might enhance MSC-mediated bone regeneration. We isolated and cultured BMMSCs from BALB/c mice and treated the cells with 0.1, 0.5, 1, 5, or 10 μM zoledronic acid (ZA; Zometa, a commercially available BP). ZA had a dose-dependent effect on BMMSCs proliferation and osteogenesis. ZA at concentrations of 5 and 10 μM inhibited the proliferation and osteogenic differentiation of BMMSCs. By contrast, in addition to inducing the proliferation and osteogenesis of BMMSCs, 0.5 μM ZA upregulated expressions of the osteogenesis-related genes Alp, osterix (Osx), and bone sialoprotein (Bsp) and enhanced osteogenesis in vivo when ZA-treated BMMSCs were implanted subcutaneously in nude mice. In addition, 0.5 μM ZA increased expression of Opg in BMMSCs, decreased the Rankl/Opg ratio, and decreased the number of osteoclasts. However, it was not associated with adverse effects on numbers of regulatory T cells or levels of Th17, transforming growth factor-β1 (TGF-β1), and interleukin-17a (IL-17a) when cocultured with T cells. In conclusion, 0.5 μM ZA pretreatment enhanced the proliferation and osteogenesis of BMMSCs in vitro and in vivo and decreased the number of osteoclasts without impairment of BMMSCs immunomodulatory properties. In vitro pretreatment of BMMSCs with BP and subsequent implantation may be a safe and effective way of enhancing MSC-mediated bone regeneration.

Effect of Alendronate with β - TCP Bone Substitute in Surgical Therapy of Periodontal Intra-Osseous Defects: A Randomized Controlled Clinical Trial

INTRODUCTION

Alendronate (ALN), an aminobisphosphonate, inhibits osteoclastic bone resorption and also stimulates osteogenesis. Beta-Tricalcium Phosphate (β-TCP) is an osteoconductive graft material which provides a scaffold for bone formation and also a widely used drug delivery vehicle for growth factors and antibiotics. Drug delivery vehicles, like β-TCP, improve the potency of the drugs by specific local site delivery of the drug, optimal release characteristics and easy handling.

AIM

The aim of the this study was to evaluate the bone formation potential of 400μg ALN delivered in β-TCP in the treatment of periodontal intra-osseous defects.

MATERIALS AND METHODS

Thirty patients with periodontal defects were randomly assigned to 400μg ALN + β-TCP + Saline (test) group and β-TCP + Saline (active-control) group. Clinical parameters like Clinical Attachment Level (CAL) gain, Probing Depth (PD) reduction, post-operative Gingival Recession (GR) were assessed from the baseline, 3 months and 6 months recordings. Radiographic parameters like Linear Bone Growth (LBG), Percentage Bone Fill (%BF), and change in alveolar crest height (ACH) were assessed from baseline and 6 months radiographs.

RESULTS

Mean measurements in the ALN test group for CAL gain (3.4 ± 0.74 mm), PD reduction (4.33 ± 0.82 mm), LBG (2.88 ± 0.88 mm), and %BF (51.98 ± 15.84%) were significantly greater with a p-value <0.05 compared to the mean measurements of CAL gain (2.20 ± 0.86 mm), PD reduction (3.20 ± 1.15 mm), LBG (1.70 ± 0.39 mm), and %BF (30.35 ± 6.88%) of the control group. There was mild alveolar crestal apposition (0.32 ± 0.68 mm) in the ALN test group and mild alveolar crestal resorption (-0.24 ± 0.40 mm) in the control group.

CONCLUSION

400μg ALN combined with β-TCP bone graft material was effective in improving soft tissue parameters, inhibiting alveolar crestal resorption and enhancing bone formation, compared to β-TCP alone.

Magnesium release from mesoporous carriers on endosseus implants does not influence bone maturation at 6 weeks in rabbit bone

OBJECTIVES

The release of magnesium ions (Mg²⁺ ) from titanium surfaces has been shown to boost the initial biological response of peri-implant bone and to increase the biomechanical strength of osseointegration. The objective of the present paper was to investigate if the initial improvement in osseointegration would influence the bone remodeling also during the maturation stage of bone healing.

METHODS

Titanium implants were coated with mesoporous titania layers and either loaded with Mg²⁺ (test group) or left untreated (control group). The implants were inserted in the tibiae of 10 New Zealand White rabbits. Osseointegration was assessed after 6 weeks by means of biomechanical testing (RTQ), non-decalcified histology and histomorphometry (BIC%, BA%, NBA%). The expression of genes involved in the bone formation and remodeling was quantified using qPCR.

RESULTS

Mg²⁺ releasing mesoporous titania coatings showed, on average, higher removal torques and histomorphometrical outcomes (RTQ: 17.2 Ncm vs. 15 Ncm; BIC: 38.8% vs. 32.1%; BA%: 71.6% vs. 64%; NBA% 62.5% vs. 54% for the tests vs the controls); however, the differences were not statistically significant. Three osteogenic markers, osteocalcin (OC), collagen 1 alpha 1 (COL1A1), and alkalin phosphatase (ALPL), were respectively 2-fold, 1.53-fold, and 1.13-fold up-regulated in the control group compared to the test. The expression of COL1A1 was particularly high in both groups, while the biomarkers for remodeling and inflammation showed a low expression in both groups.

SIGNIFICANCE

The results suggested that the initial enhancement in osseointegration induced by magnesium release from mesoporous titania coatings has no detrimental effects during bone maturation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2118-2125, 2017.