Hydroxyapatite Implants Research Articles

The application of the improved method of autologous sclera cap-shaped cover in hydroxyapatite implantation

目的 观察改良白体巩膜扣盖术对自体巩膜较小者行羟基磷灰石(HA)义眼台植入术的临床效果.方法 对10例(10眼)眼球萎缩和6例(6眼)眼内容摘除术后有自体巩膜但仅能包裹义眼台1/4～1/2者,将自体巩膜呈帽状包盖固定于义眼台前极后植入肌锥内,再与肌肉止端缝合.结果 本组16例中有14例结膜创El一期愈合,2例结膜切口裂开经保守治疗2周后自愈.术后随访3月～3年,无发生感染、义眼台暴露及交感性眼炎等并发症者.所有患者义眼活动良好,美容效果理想.结论 改良HA义眼台植入术安全可靠,适用于自体巩膜较小者。

The Use of Autogenous Sclera as Wrapping Material in Hydroxyapatite Implantation

Purpose: To report postoperative results and effectiveness using autogenous sclera as a wrapping material for hydroxyapatite orbital implant. Methods: A chart review of 78 patients (78 eyes) undergoing primary enucleation or a secondary procedure using autogenous sclera as a wrapping material from March 1997 to October 2004 was undertaken. Primary enucleation was performed in 54 eyes and secondary implantation in 24. In severely constricted eyes or eviscerated eyes with small implants, the sclera was unfolded and used for wrapping only on the anterior surface of the implant. Results: The average size of implants was 19.7 mm in diameter, and all the 78 implants were over 18 mm. During an average postoperative follow-up of 18 months, complications such as implant exposure, infection or extrusion did not occur in any case. Conclusion: This study shows that autogenous sclera is a safe, effective wrapping material for hydroxyapatite orbital implants with no serious complications.

Techniques to Study Cellular Response in Critical Size Bone Defect Healing on Rat Calvaria Treated with Hydroxyapatite Implants

The aim of this paper was to evaluate the usefulness of coupling digital image analysis with immunohistochemistry and histomorphometry data to the study of tissue response to hydroxyapatite in a model of critical size bone defect in calvaria of rats. A transosseous defect measuring 8 mm in diameter was performed with a surgical trephine in the parietal bone of 40 rats and divided into two experimental groups according to the treatment: group I (blood clot, control), group II (HA) and killed 1, 3, 6 and 9 months after implantation (n=5/group/period). The skullcaps with overlaying skin were collected and processed for paraffin embedding. The specimens were cut in the laterolateral direction into 5-µm thick semi-serial sections and stained with hematoxylin-eosin for identification and counting of polymorphonuclears cells, mastocytes, and multinucleated giant cells, MNG, or immunolabeled with anti- lysozyme, -factor VIII and –PCNA. Digital images were obtained and analyzed with the ImagePro-Plus® software for cell couting (polymorphonuclears cells, mastocytes, macrophages and MNG) and microvessel density. Image segmentation of anti-PCNA immunostaining was used for cell proliferation analysis. The digital images obtained allowed clear identification of cells of interest by through morphological aspects or immunostaining. Data recording and analysis was facilitated by the use of specific software for image processing and graphical and statistical analysis. It can be concluded that the techniques applied were usefull to identify and count cells, structures and process of interest making easier the effectiveness of hydroxyapatite in the critical size defect in rat calvaria model.

Cytotoxicity and Adhesion Evaluation of Nanothickness Ca/P-Based Bioceramics Coated Titanium

Incorporation of bioceramics on the surface of dental implants has been utilized in an attempt to increase biological response of bone to materials. This paper reports the in vitro biological evaluation of Ca/P-based nanothickness bioceramic coated alumina-blasted/acid-etched titanium implants (AB/AE nanotite implant) and compare its performance to the untreated and uncoated implants, Ca/P-based nanothickness bioceramic coated untreated implants (untreated nanotite implant), alumina-blasted/acid-etched titanium implants (AB/AE implant) and hydroxyapatite plasma-sprayed implants (PSHA Implant). Balb/c 3T3 fibroblasts were used to asses the cytocompatibility of implant materials according to ISO-10993-5 protocols. Osteoblasts from Balb/c femurs seeded onto different implant surfaces showed the effect of surface topography and chemistry on cell adhesion. The results showed that all implants were not cytotoxic and that PSHA and AB/AE nanotite implants favored osteoblasts adhesion.

O.187 Gender-speciflc patient satisfaction after free flbula flaps

The lack of bone mass associated with relatively high muscle attachments and insufficient vestibular depth complicates the prosthetic restoration of the atrophic mandibular alveolar ridge. Alloplasts and autogenous bone grafts have been used to augment the atrophic alveolar ridge with variable results. Onlay bone grafts tend to resorb while alloplastics may become infected and resorb underlying bone. The concept of interpositional bone grafting has certain theoretical advantages. It has been postulated that preservation of the integrity of the mucosa-periosteum-cortex relationship of the repositioned bone and maintenance of its morphological form and osseous architecture will minimize resorption of the transposed basal bone. An animal study was designed to test the validity of this concept. The vascularization, revascularization, and bone healing associated with interpositional autogenous bone grafts and implants of coralline hydroxyapatite were investigated in nine adult mongrel dogs. The mandibular posterior teeth were extracted and an enbloc resection of the alveolar bone which encased the extracted teeth was accomplished to simulate mandibular atrophy. Eight weeks later through an intraoral approach an autogenous cortico-cancellous iliac bone graft was placed in the edentulous area; a 2 cm. × 1 cm. × 1 cm. hydroxyapatite implant was placed on the contralateral side. The animals were sacrificed immediately, at 3 days, and 1, 2, 4, 12, 24, 28, and 40 weeks. Radiographic, microangiographic, and histological studies indicated that the lingual mucoperiosteum in the mandible provided an adequate vascular pedicle for superior repositioning of mandibular basal bone in a single stage. There was early consolidation and remodelling of the grafted bone and implant with minimal alteration of the morphological form and architecture of the repositioned bone. The results of this animal study support the concept of interpositional bone grafting to augment the atrophic mandibular alveolar ridge. The promise of coralline hydroxyapatite was favourable and awaits further ongoing comparative studies with bone grafts.

Clinical study and use of allograft acellular dermal matrix in the treatment of conjunctival sac narrow

Objective To study the clinical effect of allograft acellular dermal matrix（ADM） in the treatment of conjunctival sac narrow. Methods 26 cases（26 eyes） with conjunctival sac narrow after operation of hydroxyapatite （HA） implantation were treated with allograft acellular dermal matrix. Follow-up ranged from 6 to 18 months（averaged 11 months）. Results All of the 26 cases got satisfied clinieal effect. ADM emerged the normal colour and outward appearance of eonjunctiva 6 months postperation. No infection, necrosis or exclusion took place and good cosmetic effect were got after artificial eyes used. Conclusion It was suggested that ADM was convenient and safe on the conjunctiva sac rebuild in the eases of conjunctival sac narrow. Key words: allograft acellular dermal matrix; conjunctival sac narrow; plastic surgery

Inflammatory responses to Hydroxyapatite implants in middle ear in rats

ObjectiveTo study local inflammatory response after implantation of hydroxyapatite synthetic ossicular prosthesis. MethodsHydroxyapatite granules were implanted in the bulla in 32 rats. Sham surgical procedures were performed in 10 rats as the control. Animals were sacrificed at 1 to 300 days after surgery. Bulla sections, stained with HE and Mallory’s azan, were examined for numbers and percentages of various inflammatory cell types. ResultsSlightly more inflammatory reaction was seen in animals with the implant than in the controls, mostly during the early stage following the implantation procedure. Few inflammatory cells were observed at later times. There were satisfactory fibrosis in both implanted and control ears. ConclusionThe results indicate that hydroxyapatite synthetic prosthesis is a biocompatible implantation material in the middle ear. Nonetheless, the presence of inflammatory reaction immediately following implantation implies that control of infection is important in the early times after the implantation procedure.

Observations on the microvasculature of bone defects filled with biodegradable nanoparticulate hydroxyapatite

The microvascularization of metaphyseal bone defects filled with nanoparticulate, biodegradable hydroxyapatite biomaterial with and without platelet factors enrichment was investigated in a minipig model. Results from morphological analysis and PECAM-1 immunohistochemistry showed the formation of new blood vessels into the bone defects by sprouting and intussusception of pre-existing ones. However, no significant differences were observed in the microvascularization of the different biomaterials applied (pure versus platelet factors-enriched hydroxyapatite), concerning the number of vessels and their morphological structure at day 20 after operation. The appearance of VEGFR-2 positive endothelial progenitor cells in the connective tissue between hydroxyapatite particles was also found to be independent from platelet factors enrichment of the hydroxyapatite bone substitute. In both groups formation of lymphatic vessels was detected with a podoplanin antibody. No differences were noted between HA/PLF− and HA/PLF+ implants with respect to the podoplanin expression level, the staining pattern or number of lymphatic vessels. In conclusion, the present study demonstrates different mechanisms of blood and lymphatic vessel formation in hydroxyapatite implants in minipigs.

Measurement of extent of bone ongrowth and hydroxyapatite absorption in retrieved acetabular cups

BackgroundTo understand why hydroxyapatite (HA)-coated acetabular cups did not produce satisfactory results, we measured the extent of bone ongrowth and HA absorption of the retrieved cups. MethodsBetween March 1992 and June 1998, a total of 289 patients underwent total hip arthroplasty with an HA-coated ABG (Anatomical Benoist Giraud) prosthesis in our hospital. We revised 71 cups in our hospital, 43 of which were included in this study. The cups were in situ for an average of 80.4 months. We revised 21 cups for polyethylene wear and osteolysis, 20 for loosening, and 2 for recurrent dislocation. The outer surfaces of the cups were subdivided by two circular grooves into three areas: central, middle, peripheral. Bone ongrowth and HA absorption was measured in terms of area and thickness. The areas were graphically calculated using a computer imaging analysis system. The thickness of the HA coating remaining on the retrieved cup was measured by an x-ray coating thickness measurement instrument. ResultsOf the 43 cups, 37 had bone ongrowth. Bone ongrowth was observed on the central surface in 23 cups, on the middle surface in 27 cups, and on the peripheral surface in 15 cups; 6 of the 37 cups had bone ongrowth only in the groove. Altogether, 37 cups showed bone ongrowth on 6.43% of the outer acetabular surface. HA absorption appeared in all 43 cups, and an average 63.21% of the HA coating area was absorbed. there was a proportional relation between the rate of HA absorption and implantation duration, but there was no consistent trend between the thickness of the HA coating and implantation duration. ConclusionsWe suggest that progressive HA absorption and minimal bone ongrowth are related to the failure of HA-coated acetabular cups at long-term follow-up after total hip arthroplasty.

Clinical effect of evisceration and implantation of hydrxyapafite prosthesis

目的 探讨Ⅰ期或Ⅱ期眼内容摘除羟基磷灰石义跟座植入术的手术效果.方法 对96例(96眼)Ⅰ期或Ⅱ期行眼内容摘除、经眼球内视神经断离、自体巩膜成形、羟基磷灰石义眼座植入术,跟踪观察10-24月.结果 术后眼睑轻度肿胀,球结膜水肿,眼眶区胀痛,仅2例球结膜切口裂开,经保守治疗愈合.无义眼座暴露、脱出及感染,交感性眼炎等并发症.结论 此术式符合眼球及眼肌生理解剖,手术方便易行,并发症少,术后义眼座球体稳定,眼眶饱满,活动度好,外观逼真。

Bone reaction to nano hydroxyapatite modified titanium implants placed in a gap‐healing model

Nanohydroxyapatite materials show similar chemistry to the bone apatite and depending on the underlying topography and the method of preparation, the nanohydroxyapatite may simulate the specific arrangement of the crystals in bone. Hydroxyapatite (HA) and other CaP materials have been indicated in cases in which the optimal surgical fit is not achievable during surgery, and the HA surface properties may enhance bone filling of the defect area. In this study, very smooth electropolished titanium implants were used as substrata for nano-HA surface modification and as control. One of each implant (control and nano HA) was placed in the rabbit tibia in a surgical site 0.7 mm wider than the implant diameter, resulting in a gap of 0.35 mm on each implant side. Implant stability was ensured by a fixating plate fastened with two side screws. Topographical evaluation performed with an optical interferometer revealed the absence of microstructures on both implants and higher resolution evaluation with AFM showed similar nanoroughness parameters. Surface pores detected on the AFM measurements had similar diameter, depth, and surface porosity (%). Histological evaluation demonstrated similar bone formation for the nano HA and electropolished implants after 4 weeks of healing. These results do not support that nano-HA chemistry and nanotopography will enhance bone formation when placed in a gap-healing model. The very smooth surface may have prevented optimal activity of the material and future studies may evaluate the synergic effects of the surface chemistry, micro, and nanotopography, establishing the optimal parameters for each of them.

Integrated Orbital Implants—A Comparison of Hydroxyapatite and Porous Polyethylene Implants

Purpose: A retrospective case note review was undertaken to elucidate any differences in the cosmetic results and rate of serious complications between hydroxyapatite (HA) and porous polyethylene (PP) orbital implants. Methods: Patients who had undergone orbital implant surgery during the period 1993 to 1997 by a single surgeon were identified. Twenty-six patients had an HA implant and twenty-six had received a PP implant. All patients were reviewed in the ocular prosthetics department in a masked manner. The orbits were scored for post-enucleation socket syndrome (PESS) score, and quantification of implant mobility was done. Data analysis was conducted using Mann-Whitney U test for two independent samples. Results: There was no significant difference in PESS scores in patients with an HA or a PP implant. Implant elevation was better in patients with secondary (p = 0.029) and exchange (p = 0.042) PP implants. Only one patient in each of the HA and PP groups suffered significant implant exposure that required dermis fat and mucous membrane graft cover. Conclusions: The complication rates and PESS scores were identical between the HA and PP implant groups. The implant mobility was better in the PP group. In clinical practice, the choice of the type of orbital implant inserted may also be governed by other factors such as surgeon experience, ease of use, and cost.

Evisceration for Intractable Endogenous Endophthalmitis

Purpose: To evaluate the clinical aspects of severe endogenous endophthalmitis requiring evisceration, particularly underlying disease, causative microorganisms, and infection focus, and to assess the outcome of evisceration. Methods: The records of 13 patients who were diagnosed with endogenous endophthalmitis requiring evisceration and treated at Yeungnam University Hospital from July 1994 to April 2007 were retrospectively reviewed. Results: Of the 13 patients, all patients had diabetes mellitus, five had advanced liver disease, and one had aplastic anemia. Infection foci were pyelonephritis, pneumonia, and liver abscess. Five cases were confirmed with positive culture of Klebsiella pneumoniae. Ten cases underwent evisceration with hydroxyapatite implantation, and three cases were treated conservatively because the patient was in poor systemic condition. Of the 10 patients who underwent evisceration, ocular implants were exposed in five cases. Conclusions: This study suggests that evisceration with primary orbital implant insertion for endogenous endophthalmitis involves the risk of implant exposure, but after secondary repair, all patients have stable clinical courses.

A tissue-implant reaction associated with subcutan implantation of alpha-tricalcium phosphate, dental ceramic and hydroxyapatite bioceramics in rats

Calcium phosphate ceramics are among the more commonly used and biocompatible ceramics. Recently, we have synthesized a new calcium phosphate ceramic, alpha tricalcium phosphate (aTCP). The aim of this study was to assess the biocompatibility of this original, in our laboratory modified, newly synthesized aTCP ceramic, by carefully evaluating the inflammatory reaction of soft tissue in response to its subcutaneous implantation, and by comparing this result with the results of already widely used virtually non-toxic, non-immunogenic, and almost chemically inert dental (DC) and hydroxy apatite (HAP) ceramics. Implants (diameter 5x2 mm) of aTCP, DC and HAP were implanted into 12 adult male rats subcutaneously. At 2 weeks and 12 weeks post-implantation, the animals were euthanized and the tissueimplant reactions were analyzed histologically. Evaluation of routine stained sections (5 _m, hematoxylin & eosin) of the cutis and subcutis surrounding the aTCP, DC and HAP ceramics revealed the following: 1) all the ceramic devices had fibrous connective tissue capsules; 2) there were significant differences in the tissue - implant reactions based on the estimated time, while there were no differences in the tissue-implant reaction based on the type of ceramic material; 3) two weeks after implantation hyperemia and cellular proliferation were the most expressive results, while twelve weeks after implantation extensive angiogenesis and collagen fibers production were the prominent findings for all types of implanted calcium phosphate ceramics.

Thyroplasty with simultaneously use of silastic and Gore-Tex implants

Introduction: Type I thyroplasty for unilateral vocal fold paralysis restores voice. In medialization thyroplasty carved sailastic, prefabricated, dense hydroxyapatite and Gore-Tex implants are routinely used. Materials and Methods: In this prospectively study thyroplasty performed with simultaneously use of carved sailastic and Gore-Tex implants. Nine patients with true vocal fold paralysis due to complication of cardiac surgery, thyroidectomy and idiopatic, underwent medialization thyroplasty by this method. In six patients, just sailastic implant was used and results compared together. Results: Mean duration of follow was 9 months. 5 patients had excellent voice improvement. The voice improvement in four patients was good. In patients with only sailastic implant, just one patient had excellent voice improvement and 5 patients had dysphonia. Conclusion: In this method carved silastic is placed in thyroid cartilage window just one time and additional medialization is performed by insertion of Gore –Tex strips between cartilage and silastic implant. Resulting decreased manipulation of surgical field and surgical time, paralyzed true vocal fold edema is reduced and judgment of voice improvement was exact.

Experience with the Polymer-Coated Hydroxyapatite Implant after Enucleation in 126 Patients

Experience with the Polymer-Coated Hydroxyapatite Implant after Enucleation in 126 Patients

Hydroxyapatite implantation for rebuild of eye socket

目的 统计分析501例(501眼)羟基磷灰石义眼台植入在眼窝重建中的应用.方法 局麻或全麻下Ⅰ期植入307例,Ⅱ期植入194例.结果 480例,疗效较好.并发症21例(4.19%):主要有(1)义眼台暴露18例,10例取出.(2)结膜切口裂开11例,7例自行愈合,4例第2次缝合愈合.结论 羟基磷灰石是人体骨组织的主要无机成分,无毒,无抗原性,可安全使用。

Vascularization and biocompatibility of scaffolds consisting of different calcium phosphate compounds

Scaffolds for tissue engineering of bone should mimic bone matrix and promote vascular ingrowth. Whether synthetic hydroxyapatite and acellular dentin, both materials composed from calcium phosphate, fulfill these material properties has not been studied yet. Therefore, we herein studied in vivo the host angiogenic and inflammatory response to these biomaterials. Porous scaffolds of hydroxyapatite and isogeneic acellular dentin were implanted into the dorsal skinfold chamber of balb/c mice. Additional animals received perforated implants of isogeneic calvarial bone displaying pores similar in size and structure to those of both scaffolds. Chambers of animals without implants served as controls. Angiogenesis and neovascularization as well as inflammatory leukocyte-endothelial cell interaction and microvascular leakage were analyzed over a 14-day time period using intravital fluorescence microscopy. Implantation of both hydroxyapatite and dentin scaffolds showed a slight increase in leukocyte recruitment compared with controls. This was associated with an elevation of microvascular permeability, which was comparable to that observed in response to isogeneic bone. In addition, hydroxyapatite as well as dentin scaffolds induced a marked angiogenic response, which resulted in complete vascularization of the implants until day 14. Of interest, in hydroxyapatite scaffolds, the newly formed capillaries were not as densely meshed as in dentin scaffolds, in which the functional capillary density was comparable to that measured in bone implants. Hydroxyapatite and, in particular, dentin scaffolds promote vascularization and exhibit a biocompatibility comparable to that of isogeneic bone. This may guarantee the rapid incorporation of these materials into the host tissue.

Behavior of Cellularized-Hydroxyapatite Implants Coated with Cyclo-DfKRG Peptides in Spongious Bone: Quantitative Comparison of Micro-Tomodensitometry and Histomorphometry

In order to develop bone substitute with osteogenic properties, a novel strategy of grafting cyclo-DfKRG peptides to enhance cells adhesion and osteointegration of hydroxyapatite (HA) implants was developed. Objectives of the study were (1) to evaluate the osteogenic properties of HA implants grafted with RGD peptides and (2) to compare histomorphometry and micro-computed tomography ((CT) with bone quantification. Pure HA grafted or not with cyclo- DfKRG peptides and autologous stromal cells was implanted in femoral condyle on 2 groups (2 and 4 weeks) of 6 New Zealand rabbits. Measurements concerning bone reconstruction and material structure were obtained with a (CT and the results were compared to those obtained after histomorphometry. Finally, it appears that grafting cyclo-DfKRG on HA implants enhances nonsignificantly the rate of bone formation, and a high correlation of the results was found comparing histomorphometry and (CT analysis.

Exposure Rate of Hydroxyapatite Orbital Implants: A 15-Year Experience of 802 Cases

To document the long-term experience with hydroxyapatite (HA) orbital implants (Bio-Eye) and analyze the factors influencing implant exposure, including surgical type, procedural modification, use of different wrapping materials and peg materials. Retrospective observational case series. Eight hundred two eyes from 802 patients who underwent anophthalmic socket surgery (eviscerations, enucleations, secondary implant placements) using HA implants, performed by one surgeon between May 1990 and December 2005. All patients' clinical records were reviewed. Baseline age, cause of anophthalmic surgery, surgical type, size of HA implant, wrapping material, and peg system were recorded. Postoperative complications, especially implant exposure, were recorded separately before and after pegging, and compared according to type of surgery, wrapping material, and peg system. The main cause of anophthalmic surgery was trauma (73%). A variety of wrapping materials have been used, including Tutoplast-dura, Vicryl mesh, autogenous sclera, and polyester-urethane. Implant exposure occurred in 17 patients (2.1%) before pegging and 14 (4.0%) after pegging. The exposure rate was significantly higher in eyes eviscerated without (7.2%) than with (1.1%) keratectomy (P = 0.018), but did not differ according to type of surgery (P = 0.710). When distributed according to 5-year periods, the exposure rate was higher from 1990 to 1994 (4.7%) than in later periods (P = 0.004). In patients who underwent enucleation or secondary implantation, there was no difference in exposure rate between Tutoplast-dura- and Vicryl mesh-wrapped implants (P = 0.235). Among the 353 patients (44.0%) who underwent pegging, those who received titanium-pegged implants had a significantly lower incidence of peg extrusion (5.2%), major discharge (5.2%), and pyogenic granuloma (9.1%) than those with nonsleeved polymethyl methacrylate and sleeved polycarbonate peg materials (P<0.05). Exposures associated with HA orbital implants decreased with the improvement of surgical technique over time and have been managed successfully, both before and after pegging. The incidence of peg-related complications have decreased since the introduction of the titanium peg system.