Periodontal ligament formation around titanium implants using cultured periodontal ligament cells: a pilot study

The aim of this study was to investigate whether a new periodontal ligament attachment will form on titanium implants when they are implanted with cultured periodontal ligament cells. Periodontal ligament cells obtained from the teeth of 3 dogs were cultured and attached to the surface of titanium implants. The implants with the cultured autologous periodontal ligament cells were placed in the mandibles of the dogs. After 3 months of healing, histologic examination revealed that, on some implant surfaces, a layer of cementum-like tissue with inserting collagen fibers had been achieved. These results demonstrated that cultured periodontal ligament cells can form tissue resembling a true periodontal ligament around implants.     

The interface between retained roots and dental implants: a histologic study in baboons

BACKGROUND: This study is a derivative of another study evaluating implant efficacy in baboons. In the previous study it was noted that some implants were placed near or into retained root tips. The purpose of this study was to evaluate the effect of the inadvertent placement of root form implants into or near retained root fragments. METHODS: The baboon has severe dilacerations at the apices of the roots, making extraction very difficult; 120 teeth were extracted from 10 baboons. After the sites had healed, root form implants were placed in each of the sites. Sites were either loaded at various time intervals or left unloaded. Block sections were removed and processed for histologic examination. RESULTS: When the specimens were analyzed, it was noted that several implants were placed through retained root fragments, while others were placed through the periodontal ligament of other root fragments. In a few cases, implants were close to, but not in contact with, either the root or the periodontal ligament. These implants functioned as well as the others in the study. Histologically, there was no inflammation at any site. In some sections, the roots were in intimate contact with the implants, while in others, there was a gap between the two. Where the implant was in contact with the periodontal ligament, there was no apparent fibrous encapsulization of the implant. In some areas, it appeared that a calcified material was deposited on the implants. It was not possible to determine whether this material was bone or cementum. CONCLUSION: Unintentional placement of dental implants into retained root fragments did not result in any inflammation and may have produced cementum or cementum-like matrix on the titanium surface adjacent to the periodontal ligament of the retained root tip.     

Integrin mediated attachment of periodontal ligament to titanium surfaces

ObjectiveReducing the force between the implant and the bone by recapitulating a similar matrix has the potential to reduce implant failure. To begin to pursue the goal of creating a periodontal ligament interface between a dental implant and bone, the mechanism of cellular attachment to dental implant surfaces must be characterized.MethodsIn this study we examined the role of integrin receptors in the attachment of periodontal ligament fibroblasts to titanium surfaces utilized on dental implants; those surfaces included smooth polished titanium, acid pickled titanium, ground titanium, sandblasted and acid etched titanium, non-oxidized titanium that has been sandblasted and acid etched, hydroxyapatite coated titanium, titanium plasma sprayed or uncoated titanium. For these studies integrin mediated fibroblast attachment was blocked by the integrin blocking peptide GRGDSP or anti-integrin β1 antibody or a combination of the two. Quantitation of periodontal ligament fibroblast attachment was completed by counting cells on the various implant surfaces after culturing in vitro for 24 h with and without the integrin receptor blockers.ResultsAntibody and peptide treatment significantly reduced the number of fibroblasts cells attached to the various implant surfaces but this effect varied significantly depending on the surface. Moreover, increased levels of peptide further decreased fibroblasts attachment in a dose dependent manner.SignificanceBlocking studies suggest first, that integrin receptors function in periodontal ligament attachment to titanium surfaces and second, that different integrin subunits are important in attachment to a particular surface.     

New formation of periodontal tissues around titanium implants in a novel dentin chamber model

Direct bone-to-implant contact, defined as "osseointegration", is considered most optimal for long-term stability and survival of dental implants. However, the possibility of the formation of a tooth-like attachment apparatus around implants has also been demonstrated. The purpose of this study was to explore the formation of periodontal tissues around titanium implants using a novel and unique experimental model. After resection of the crowns of the maxillary canine teeth in nine mongrel dogs, the roots were hollowed to a depth of 5 mm leaving a thin dentinal wall. Slits were prepared in the cavity wall to create passages from the chamber to the periodontal ligament area. A custom-made, titanium implant was placed into the center of each chamber. Machined, titanium plasma sprayed (TPS) and sand blasted with large grit and acid attacked (SLA) surfaces were used. A collagen barrier was placed over the submerged chamber. Following 4 months of healing, jaw sections were processed for histology. Newly formed periodontal ligament, alveolar bone, and root cementum filled the space between the implant and the wall of the chamber. Ingrown bone was neither in contact with dentin nor with the implant. Thus, an interposed soft connective tissue layer was present. Healing by fibrous encapsulation was observed around most implants. However, cellular cementum was deposited on one TPS and one SLA implant and on the dentinal walls of the chamber. This study shows a remarkable capacity for new periodontal tissue formation at a site where no such tissues ever existed. Maintenance of original periodontal tissue domains most likely prevented osseointegration of the implants. The cementum layer deposited on two implants was likely formed through cementoconductivity rather than by differentiation of periodontal ligament cells upon contact with the implant surface.     

Cementum formation around a titanium implant: a case report

Animal studies have shown that a periodontal ligament may be produced around a titanium implant when it is in contact with fractured and retained roots. Formation of cementum and attachment connective tissue around titanium implants confirms that cementum progenitor cells are located in the periodontal ligament, since cementum and periodontal ligament are present at the implant-root interface, whereas the remainder of the implant, which is not in contact with the root, shows osseointegration. The aim was to evaluate histologically the characteristics of the tissue present between a titanium implant and a retained root, which were subsequently extracted as a result of peri-implantitis. The histologic examination revealed a continuous layer of cementum and numerous cementocytes on the implant surface. No blood vessel or collagen fibers were detected in the periodontal space. In contrast to experimental studies carried out on animals, the lack of connective tissue fibers and the presence of hypercementosis in this specimen could have been caused by the inflammatory process. Furthermore, the extrusive movement of the root might explain the presence of cementum hypertrophy. Further studies are required to establish whether the neoformation of cementum and collagen fibers on an implant in the presence of root residues occurs only in animal models or whether it may also occur in humans.     

Dentointegration of a titanium implant: a case report

Purpose

This case illustrates a pulp tissue-induced dentointegration of a titanium implant.

Materials and methods

One commercially available titanium implant with a sand-blasted and acid-etched surface was placed in the maxilla of a foxhound where the palatinal root of the previously (i.e., 8 weeks) removed first molar was unintentionally retained. After 8 weeks of nonsubmerged healing, the dissected block was prepared for immunohistochemical (osteocalcin) and histomorphometrical analysis.

Results

A reparative hard tissue had formed within the artificially opened pulp canal. Also, the external layer of the exposed dentin due to the root fracture during tooth removal further developed into an atubular reparative dentin thus establishing a close contact with the adjacent titanium implant surface. The entire contact zone was demarcated by an intense osteocalcin antigen reactivity. A thin layer of osteocementum originated from the root surface and superimposed implant integration in the peripheral areas. Mean contact of osteodentin/osteocementum to the implant surface was 67.4 %, whereas bone-to-implant contact at the vestibular aspect was 63.5 %.

Conclusion

The present case report provides the first histological evidence for a pulp tissue-induced dentointegration of a titanium implant.     

A light and scanning electron microscopy study of bone healing following inferior alveolar nerve lateralization: an experimental study in rabbits

PURPOSE: The purpose of this study was to evaluate the bone healing kinetics around commercially pure titanium implants following inferior alveolar nerve (IAN) lateralization in a rabbit model. MATERIALS AND METHODS: Inferior alveolar nerve lateralization was performed in 16 adult female rabbits (Oryctolagus cuniculus). During the nerve lateralization procedure, 1 implant was placed through the mandibular canal, and the IAN was replaced in direct contact with the implant. During the 8-week healing period, various bone labels were administered for fluorescent microscopy analysis. The animals were euthanized by anesthesia overdose, and the mandibular blocks were exposed by sharp dissection. Nondecalcified samples were prepared for optical light and scanning electron microscopy (SEM) evaluation. RESULTS: SEM evaluation showed bone modeling/remodeling between the IAN and implant surface. Fluorochrome area fraction labeling at different times during the healing period showed that bone apposition mainly occurred during the first 2 weeks after implantation. CONCLUSIONS: The results obtained showed that bone healing/deposition occurred between the alveolar nerves in contact with a commercially pure titanium implant. No interaction between the nerve and the implant was detected after the 8-week healing period. Appositional bone healing occurred around the nerve bundle structure, restoring the mandibular canal integrity and morphology.     

Ultrastructural changes of smooth and rough titanium implant surfaces induced by metal and plastic periodontal probes

Objectives

To determine the ultrastructural changes of titanium surfaces of dental implants induced by the tip of periodontal probes.

Materials and methods

A total of 40 samples of smooth and rough surfaces of titanium implants were randomly assigned for the treatment with metal or plastic periodontal probes under application angles of 20° and 60°. Titanium surfaces have been evaluated with CLSM prior and following to experimental probing determining various standardized 2D and 3D roughness parameters.

Results

The average profile and surface roughness (Ra and Sa) showed no significant difference between treated and untreated samples on smooth and rough surface areas irrespective of the probe material. On smooth surfaces several amplitude roughness parameters were increased with metal probes but reached significance only for Rp (p = 0.007). Rough surface parts showed a slight but not significant reduction of roughness following to the contact with metal probes. The surface roughness remained almost unchanged on smooth and rough implant surfaces using plastic probes. The surface roughness on implant surfaces was not dependent on the application angle irrespective of the probe material.

Conclusion

Probing of titanium implants with metal probes and even less with plastic probes causes only minor changes of the surface roughness. The clinical significance of these changes remains to be elucidated.

Clinical relevance

Using plastic probes for the clinical evaluation of the peri-implant sulcus might avoid ultrastructural changes to titanium implant surfaces.

     

钛种植体-羟基磷灰石复合型植入体修复下颌骨缺损的动物实验

本研究采用钛种植体-羟基磷友石复合型植入体植入20只狗下颌骨牙缺失区．并对植入体与宿主骨结合的过程进行了X线、组织形态学观察和复合型植入体抗折强度测试。结果表明：术后12周．复合型植入体的抗折强度比植入体内前高；复合型植入体植入后用微型钛夹板固定组与宿主骨呈骨性结合；用骨膜复位缝合固定组与宿主骨呈纤维骨性结舍。钛种植体与羟基磷灰结合牢固．负荷条件下无松脱落。复合型植入体不干扰骨愈合过程。作者认为该种复合型植入体可用于颌骨缺损后的牙颌整复．但植入体植入后早期的稳定固定则十分重要。     

Trabecular bone response to titanium implants with a thin carbonate-containing apatite coating applied using the molecular precursor method

PURPOSE: The influence of thin carbonate-containing apatite (CA) coating on the trabecular bone response to titanium implants was investigated. MATERIALS AND METHODS: Thin CA coatings were deposited by a new method known as the molecular precursor method. Using a precursor solution composed of an EDTA-calcium complex, a CA film was deposited on the titanium surfaces. Uncoated and CA-coated titanium were placed in the trabecular bone of the left and right femoral condyles of 16 rabbits. After implantation periods of 2, 4, 8, and 12 weeks, the bone-implant interface was evaluated histologically and histomorphometrically. RESULTS: Histologic evaluation revealed new bone formation around the uncoated and CA-coated implant surfaces after only 4 weeks of implantation. After 12 weeks, mature trabecular bone surrounded all implants. At 4 and 8 weeks of implantation, no difference existed in bone contact between uncoated and CA-coated implants. After 12 weeks of implantation, the CA-coated implant group showed a significantly higher percentage of bone contact than the uncoated implant group. DISCUSSION AND CONCLUSION: The present study demonstrated that thin CA coatings applied using the molecular precursor method showed greater bone-to-implant contact during the healing phase than uncoated controls. The results were similar to those observed with implants with calcium phosphate coatings deposited with a physical vapor deposition technique.     

Formation of a periodontal ligament around titanium implants

The aim of this study was to examine wound healing events around titanium implants in the presence of retained root tips whose periodontium could serve as a source for cells which could participate in the healing process. Hollow cylinder implants with a titanium plasma-sprayed surface were placed in the mandible of monkeys where the apical portions of previously removed teeth were retained. After a healing period of 12 months, free of functional loading, the implants with surrounding tissues were removed and specimens analyzed in undecalcified sections. This report describes histologic findings of six such implants. Microscopic analysis revealed that in regions where implants were close to retained roots, a periodontal ligament had formed around large portions of the implant. Furthermore, there was a distinct layer of cementum on the implant surface and a periodontal ligament with collagen fibers perpendicularly oriented to the implant surface, implanted into the cementum on the implant surface as well as to the opposing bone. This initial observation suggests that it may be possible to achieve an anchorage of certain dental implants with a periodontium simulating that found surrounding the normal tooth. Furthermore, these findings provide the basis for further studies on regeneration of all components of the periodontal attachment apparatus including cementum, periodontal ligament, and bone.     

Partial generation of periodontal ligament on endosseous dental implants in dogs

OBJECTIVES: The objective of this pilot study was to investigate the feasibility of periodontal ligament (PDL) generation on an implant surface by approximating a tooth-to-implant contact using orthodontics. METHODS: Maxillary second premolars of six beagle dogs were extracted bilaterally. After 2 weeks of healing, hydroxyapatite (HA) coated titanium implants, 5 mm in length and 3.3 mm in diameter, were placed in the extraction sites. One side of the arch was used as control. Orthodontic tooth movement was initiated following implant placement to tip the first premolar roots into contact with the implant. This was achieved in 4-6 weeks as confirmed radiographically. Tooth-to-implant contact was maintained for further 6 weeks after which time, teeth were separated from implant contact orthodontically. After further 2 weeks of stabilization, the animals were sacrificed. Samples were analyzed by Faxitron radiographs before histology. Histology samples were prepared with Stevenel's Blue and Van Gieson stain and were subjected to polarized light microscopy. RESULTS: Histologic analysis revealed transfer and formation of PDL-like structure with formation of cellular cementum on the implant surfaces, in four out of six animals, where tooth-to-implant contact had been achieved. Direct bone-to-implant contact was noted in the areas coronal to the PDL-like tissue, an important sign to distinguish between PDL-like tissue and connective tissue that could originate from the coronal portion of a failing implant. Additionally, at the site of contact, the implant surface revealed some resorption of the HA coating. CONCLUSION: An animal model was established in which the proximity of tooth-to-implant contact lead to partial generation of PDL on a bioactive implant surface in four out of six animals.     

Response of human fibroblasts to implant surface coated with titanium dioxide photocatalytic films

PurposeThis study was to develop a titanium dioxide (TiO₂)-coated implant abutment, surface with ultraviolet (UV) light-induced hydrophilicity and investigate the initial response of human, fibroblasts to the surface modification.Materials and methodsCommercially pure titanium (JIS 2 grade) disks were coated with TiO₂ to various, thicknesses (1, 2 or 3 μm) using peroxotitanium acid solution. The surface characteristics of each disk, were examined with X-ray diffraction (XRD), surface roughness equipment and scanning electron, microscopy (SEM). The hydrophilic change of each disk was determined by the contact angles at 0–24 h, after 24-h UV irradiation. The biological response at the surface of each disk was examined by using, human periodontal ligament fibroblasts (HPLFs). The data were statistically analyzed with analysis of variance (ANOVA) and multiple-comparison tests.ResultsThe TiO₂-coated disk surface had an anatase structure. Surface roughness did not differ, significantly among the disks; the surface morphology was smooth and had a hydrophilic or superhydrophilic, status. HPLF proliferation significantly increased on the TiO₂-coated disks compared with the uncoated disks and depended upon the coated film thickness.ConclusionAn anatase TiO₂-coated surface under UV irradiation markedly improves the initial response of human fibroblasts.     

Optimal design of an individual endoprosthesis for the reconstruction of extensive mandibular defects with finite element analysis

AimThe aim of this study was to evaluate the finite element analysis (FEA) approach to assess biomechanical performance of individual endoprostheses used in the reconstruction of extensive mandibular defects, and to explore an available strategy for the optimal design of prostheses.Material and methodsA female patient experienced fracture of a titanium mandibular endoprosthesis one year after reconstructive surgery. The endoprosthesis was placed during resection of a mandibular carcinoma. Using CT data, a finite element analysis (FEA) of the implant was performed to identify potential causes for this mechanical failure. Based on the first FEA analysis, modifications of the prosthesis geometry and screw configuration were carried out. FEA was performed for each subsequent modification until no stress concentration areas were identified. The final version of the titanium prosthesis was implanted during the second mandibular reconstruction.ResultsThe FEA model was constructed, based on the geometrical data of the patient. Two areas of stress concentration were identified in the original prosthesis:- at the top surface of the left stem, 1.5 cm away from the corner (the peak stress was 616 MPa) and- on the exterior surface of the right stem, close to the mandibular stump margin.The mechanical failure occurred at the top surface of the left stem. Some common characteristics of the biomechanical performance were noted in the two models, but lower overall stress was achieved in the second, optimized prosthesis. By thickening the recognized high stress areas, and attenuating those areas subject to less stress, then adopting a quadrilateral screw configuration, this dispersed the stress more evenly in the optimized endoprosthesis. Function in the optimized reconstructed mandible was observed for 3 years without significant endoprosthesis related complication.ConclusionIn some patients with extensive mandibular defects, the individually tailored endoprosthesis constructed with regard to minimizing stress concentration using this method seems to have a place. The prosthesis geometry and screw configuration influence the stress–strain distribution on the reconstructed mandible. Our FEA approach can optimize the design of individual endoprostheses and give the reconstructed mandible improved biomechanical performance.     

Observations of the bone activity adjacent to unloaded dental implants coated with Polyactive® or HA

Summary In addition to bone-bonding bioma-terials such as calcium phosphate ceramics and Bioglass/glass ceramics, an elastomeric poly(ethylene oxide) poly(butylene terephthalate) (PEO/PBT) segmented block co-polymer (Polyactive®) was recently introduced. In contrast to ceramic bioma-terials, Polyactive® is a flexible material. In a previous three-dimensional finite element analysis study, it was stated that application of a flexible Polyactive® coating simulates the function of the periodontal ligament. The topic of this investigation was to compare the bone-bonding capacity of Polyactive®-coated titanium implants with hydroxylapatite (HA) coated implants. The implants were inserted bilaterally in the edentulous part of the mandibular bone of 12 goats. After 3 weeks, the implants were in close contact with the cortical bone, but no cortical bone reaction or remodelling was observed. After 9 weeks, an extensive bone reaction was seen around the HA and Polyactive®-coated implants and contact was frequently encountered between newly formed bone and the implants. Within the surface of the Polyactive® coating, a considerable amount of calcification was present. After 25 weeks, cortical remodelling was still apparent. A striking finding was the apparent association between osteon formation and calcification within the surface of the Polyactive® layer. Back-scatter analysis of the non-decalcified Polyactive® bone interface showed the presence of a calcium phosphate layer in the implant material that apparently formed a continuity with the mineral matrix of bone, suggesting bone-bonding. In general, it was observed that the bone reactions to HA and Polyactive® were comparable. A swelling of the coating, just beneath the cortical layer (champagne-cork effect) was often seen. This increase in volume, caused by water uptake, might result in a more intimate initial bone/Polyactive® contact, as compared with other implant materials.     

Histomorphometric analysis of the osseointegration of four different implant surfaces in the femoral epiphyses of rabbits

Objectives: The surface properties of titanium dental implants are key parameters for rapid and intimate bone–implant contact. The osseointegration of four implant surfaces was studied in the femoral epiphyses of rabbits. Material and methods: Titanium implants were either grit‐blasted with alumina or biphasic calcium phosphate (BCP) ceramic particles, coated with a thin octacalcium phosphate (OCP) layer, or prepared by large‐grit sand blasting and acid‐etched (SLA). After 2 and 8 weeks of implantation, the bone‐implant contact and bone growth inside the chambers were compared. Scanning electron microscopy (SEM) and profilometry showed distinct microtopographies. Results: The alumina‐Ti, BCP‐Ti and OCP‐Ti groups had similar average surface roughness in the 1–2 μm range whereas the SLA surface was significantly higher with a roughness averaging 4.5 μm. Concerning the osseointegration, the study demonstrated a significantly greater bone‐to‐implant contact for both the SLA and OCP‐Ti surfaces as compared with the grit‐blasted surfaces, alumina‐ and BCP‐Ti at both 2 and 8 weeks of healing. Conclusion: In this animal model, a biomimetic calcium phosphate coating gave similar osseointegration to the SLA surface. This biomimetic coating method may enhance the apposition of bone onto titanium dental implants.     

非血管化骨移植种植体以及即刻种植体与软组织结合的实验观察

目的:观察非血管化骨移植种植以及即刻种植体钛金属表面与软组织的结合状况,分析影响二者结合的因素。方法:拔除狗的一侧下颌前磨牙,4周后截除无牙下颌骨段,自体非血管化髂骨移植同时植入纯钛种植体修复下颌骨缺损。对照组动物拔除一侧下颌前磨牙时同期在牙槽窝内植入同样的种植体,缝合牙龈。在术后4、8、16周处死动物,以40g/L中性多聚甲醛灌注固定后,取种植体颈部周围软组织。肉眼观察2组动物种植体与周围软组织结合的紧密程度;HE染色观察结合上皮的组织结构;透射电镜观察结合上皮与种植体结合面细胞超微结构。结果:2组动物在术后4周时,种植体顶端已出龈暴露在口腔内,颈部周围的软组织已达初步封闭;两者的结合还较疏松,软组织较薄,细胞膜的表面突起较少。术后8周时,种植体的颈部软组织已完全封闭,软组织与钛表面结合紧密,即刻种植组动物可见明显的结合上皮;超微结构可见结合上皮有较多的细胞膜突起。术后16周,2组的结果与8周时相似。整个实验过程未发现桥粒结构的形成。结论:在没有明显创伤和感染的情况下,两者均可形成良好的结合;即刻种植体与周围软组织结合较非血管化骨移植种植体更致密。2种种植方法结合上皮与钛表面都不能形成桥粒结构。     

Changes in the microcirculation in periodontal tissue due to experimental peri-implantitis

ObjectivesPeri-implantitis causes dislodgement of dental implants due to inflammation in the peri-implant tissue. The microcirculation in the periodontal tissue undergoes morphological and physiological changes due to inflammation. The immune mechanism of peri-implantitis differs from that of periodontitis. In this study, we examined the changes in the microcirculation in the peri-implant tissue with experimentally induced inflammation, using morphological and physiological techniques.MethodsSix beagle dogs were used in the experiment. After extracting both mandibular premolars, three titanium screw implants were inserted on each side of the mandibular jaw. Dental floss was placed on the right side for 90 days in the study group but not in the control group. Microvascular resin cast models were created, and morphological changes were observed using scanning electron microscopy. Periodontal blood flow was measured using laser Doppler flowmetry.ResultsNinety days after induction of inflammation, bone resorption was observed around the implant body. Osseointegration was impaired, and a gap at the implant–bone interface was observed. The resin cast models showed that inflamed gingival blood vessels had invaded the bone marrow through the resorbed apical margin of the alveolar bone. Analysis of the physiological data obtained using laser Doppler flowmetry showed a significant increase in blood flow around the implants with experimentally induced inflammation.ConclusionsSignificant morphological and physiological changes occur in the gingival microcirculation of peri-implant tissue due to inflammation. Evaluating the vasculature and blood flow in the tissue surrounding the site of peri-implantitis may be helpful for pathologic analysis in clinical settings.     

One vs. two piece customized implants to reconstruct mandibular continuity defects: A preliminary study in pig cadavers

ObjectivesThe reconstruction of mandibular continuity defects by bridging plates often leads to complications. Customized mandibular implants might be an alternative option. In the present study, the stability at the bone–implant-interface of customized two-piece implants was compared to one-piece implants.MethodsThirty pig mandibles were randomly divided into three groups. One group (A) was left untreated and served as reference. In groups B and C, a continuity defect was created in the left mandibular side. The defects were reconstructed by customized pure titanium implants, manufactured using the LaserCUSING^® technology. Group B received a one-piece implant; in group C a two-piece implant was inserted to reconstruct the continuity defect. The bonding strength was examined statically and dynamically under standardized conditions. Digital Image Correlation was used for distortion measurement. Different dynamic measurements were performed for orientation purposes.ResultsThe highest bonding strength was measured for the reference group. The two-piece implant showed an increased bonding strength when compared to the one-piece design. In all pig mandibles treated with individual implants a fracture occurred on the non-operated side. This indicates a high primary stability of the bone–implant-interface.ConclusionThe two-piece individual mandibular implant manufactured by LaserCUSING^® technology should be further analyzed in future studies.     

Osteoconduction of a stoichiometric and bovine hydroxyapatite bilayer-coated implant

Objective: To impart rapid and durable osteoconductivity to implants, a commercial titanium screw implant was coated with stoichiometric hydroxyapatite (HA; 50 nm thick), and then with bovine hydroxyapatite (B‐HA; 300 nm thick) using the pulsed laser deposition technique. As control specimens, a commercial implant coated with HA (20 μm thick) using the flame spraying method (sprayed implant) and a simple titanium implant (basic implant) was used. Methods: The osteoconductivities of these three types of implant, after implantation for 4–24 weeks, were histologically evaluated. Results: Peeling of HA from the sprayed implant was observed by scanning electron microscopic observation. In the fourth postoperative week, the bilayered implant was already closely adhered to bone. On the other hand, the basic implant was surrounded by a gap containing connective tissue. With the sprayed implant, the bone adhered to the thick HA coating. Conclusion: The bilayer deposition technique supplies quick and long‐term fixation of implants to bone, because the B‐HA film dissolves to aid osteoconduction right immediately after implantation and the HA thin film maintains osteoconduction without dissolution. Neither of the thin‐film fractures easily compared with thick coatings. To cite this article:
Hayami T, Hontsu S, Higuchi Y, Nishikawa H, Kusunoki M. Osteoconduction of a stoichiometric and bovine hydroxyapatite bilayer‐coated implant.
Clin. Oral Impl. Res. 22 , 2011; 774–776
doi: 10.1111/j.1600‐0501.2010.02057.x