Sharpey's Fibers Research Articles

Periodontal regeneration by application of recombinant human bone morphogenetic protein-2 to horizontal circumferential defects created by experimental periodontitis in beagle dogs.

The purpose of this study was to examine the regeneration of periodontal tissue after the application of recombinant human bone morphogenetic protein-2 (rhBMP-2) to horizontal circumferential defects created by experimental periodontitis. Twelve mandibular second premolars in 6 adult beagle dogs were subjected to experimental periodontal breakdown by placing silk ligatures around the teeth until the bone loss exceeded half of the root length. Flap surgery was then performed and the exposed cementum removed. The distance between the bone crest and cemento-enamel junction (CEJ) was about 5 mm. RhBMP-2 (40 micrograms/100 microliters) with a sponge-type carrier material made of gelatin and polylactic acid polyglycolic acid copolymer was placed in the furcation area (5 mm x 5 mm x 5 mm) and around the roots (10 mm x 5 mm x 2.5 mm x 2 pieces). In the control group, the same carrier material without rhBMP-2 was placed in the same manner. The flaps were replaced and sutured to cover these materials completely. Twelve weeks after surgery, the animals were sacrificed and serial sections were prepared in a bucco-lingual plane. Considerable new bone formation was observed in the rhBMP-2-treated sites. New cementum with Sharpey's fibers was observed on the instrumented root surface. On histometric analysis, the amount of new bone, new cementum, and connective tissue attachment was significantly greater in the rhBMP-2-treated group (paired t test; P < 0.01). These results indicate that suitable application of rhBMP-2 can produce considerable periodontal tissue regeneration, even in cases of horizontal circumferential defects.

In vitro fatigue behavior of the equine third metacarpus: remodeling and microcrack damage analysis.

We studied remodeling and microcrack damage in specimens of Thoroughbred racehorse third metacarpal bone that had been subjected to monotonic or fatigue failure. We asked three questions. What effects does mechanical loading have on histologically observable microcrack damage? Are there regional variations in remodeling of the equine cannon bone, and do these variations correlate with mechanical properties? To what extent are remodeling and microcrack damage age-dependent? Machined beams from the medial, lateral, and dorsal cortices were loaded to fracture in four-point bending monotonically, or cyclically at a load initially producing 10,000 microstrain. Specimens were then bulk-stained in basic fuchsin, and cross sections were prepared from loaded and load-free regions of each beam. Current and past remodeling, porosity, and microcrack density and length were determined histomorphometrically. Strained and unstained microcracks were observed. Unstained cracks were associated with regions of woven bone and appeared to be damaged Sharpey's fibers. Their density (approximately 30/mm2) did not increase after failure, but their length (approximately 25 microns) did, especially near the surfaces of the beam. Stained cracks were wider and longer than unstained cracks and were located primarily near the fracture surface and on the compressed side of the beam. Stained cracks after failure were more numerous in those beams having a higher elastic modulus, a shorter fatigue life, or greater deformation at failure. The extent of past remodeling increased with age, especially in the medial region; the rate of current remodeling generally declined with age, but not in the dorsal region, which has the best fatigue resistance. In summary, while remodeling varied with age and region, its effects on bone structure did not appear to influence microdamage. Basic fuchsin staining of damage in fractured equine bone was independent of age and region and confined to near the fracture surfaces. Distributed microdamage consisted only of what appeared to be subtle disruptions of Sharpey's fibers.

Extracellular matrix in tooth cementum and mantle dentin: localization of osteopontin and other noncollagenous proteins, plasma proteins, and glycoconjugates by electron microscopy.

Noncollagenous proteins (NCPs) are considered to have multiple functions related to the formation, turnover, and repair of the collagen-based mineralized tissues. Collectively, they comprise a class of generally acidic, mineral-binding proteins showing extensive posttranslational modifications, including glycosylation, phosphorylation, and sulfation. METHODS. We have used colloidal-gold immunocytochemistry and lectin-gold cytochemistry, together with transmission electron microscopy, to examine the organic matrix composition of tooth cementum and the subjacent mantle dentin in rodent molar teeth. Molars were processed for immunocytochemistry using antibodies against osteopontin (OPN), osteocalcin (OC), bone sialoprotein (BSP), bone acidic glycoprotein-75 (BAG-75), albumin (ALB), and alpha 2HS-glycoprotein (alpha 2HS-GP), or for glycoconjugate cytochemistry using lectin-gold complexes. Ultrastructurally, at the advancing root edge in developing molars, OPN and BSP initially were associated with small calcification foci in the mantle dentin. With progressing mineralization, OC and alpha 2HS-GP appeared diffusely distributed throughout the calcified mantle dentin, and diminished as a gradient toward the circumpulpal dentin. Immediately following disruption of Hertwig's epithelial root sheath, cementum deposition commenced at the root surface occasionally with the appearance of a cement line rich in OPN. Cementum matrix proper contained abundant OPN, BSP, OC, and alpha 2HS-GP, but no or little BAG-75 or ALB. Protein immunolabeling, as well as lectin labeling for beta-D-galactose and N-acetyl-neuraminic acid and/or N-glycolyl-neuraminic acid, both being prominent sugars of certain NCPs, was primarily concentrated between, and at the surface of, collagen fibrils in acellular extrinsic fiber cementum. OPN, BSP, OC, and alpha 2HS-GP were also prominent components of cellular cementum and of Sharpey's fibers. In cellular cementum, laminae limitantes sometimes present delimiting cementocyte lacunae and cell process-containing canaliculi were also rich in OPN. Along the root surface, occasional cementoblasts exhibited intracellular labeling for OPN over the Golgi apparatus and secretory granules. We have identified OPN, BSP, OC, and alpha 2HS-GP as being prominent organic constituents of both mantle dentin and acellular and cellular cementum, and, have elucidated the details of their distribution at the ultrastructural level. The temporal appearance and spatial distribution of these organic moieties in the teeth root are similar to those seen during bone formation and are consistent with proposals that certain NCPs may be involved in regulating calcification and/or participating in cell-matrix and matrix-matrix/mineral adhesion events.

Histological observations on structure of bundle bone in area of mylohyoid line

The purpose of this study was to investigate the structure and the function of the part of the mandible where mylohyoid muscle originates. The bundle bone in the area of mylohyoid line and the tendon fibers on the surface of the bundle bone were observed by light microscopy and scanning and transmission electron microscopy. The conclusions were as follows: 1. It seemed that remodeling occurs frequently in bundle bone in the area of the mylohyoid line. 2. Sharpey's fibers in bundle bone in the area of the mylohyoid line seemed to be flexible. This suggested that Sharpey's fibers can be adapted to the tension from directions that are different to a certain degree. 3. Both directions of Sharpey's fibers in bundle bone in the area of the mylohyoid line and the tendon fibers on the surface of bundle bone were fundamentally the same as that of the muscle fibers of the mylohyoid muscle. But a few existing fibers crossed these fibers. Such Sharpey's fibers and tendon fibers seemed to prevent the exfoliation of the periosteum, and seemed to support main tendon fibers of the mylohyoid muscle when it is contracting.

Observations of the structure of incremental lines in acellular cementum

The purpose of this study was to investigate the function of human cementum from a morphological viewpoint. To accomplish this purpose, the incremental lines in human acellular cementum were studied by light microscopy, microradiogram (CMR), scanning electron microscopy, and transmission electron microscopy, and the results were as follows: 1. In acellular cementum, many fine incremental lines of about 0.5 micron width were observed. 2. The fine incremental lines were observed running perpendicularly or obliquely to Sharpey's fibers in the acellular cementum. 3. The fine incremental lines observed in acellular cementum were not straight lines but had wave-like structure. 4. Each wave observed in the fine incremental lines corresponded to a bundle of Sharpey's fibers. 5. The fine incremental lines observed on Sharpey's fibers in acellular cementum showed specific characteristic features. 6. Despite the fine incremental lines showing a close relationship to the degree of calcification, they also seemed to show a strong relationship to the quality of the organic component of the acellular cementum. 7. Apart from the fine incremental lines which are specific to acellular cementum, incremental lines similar to those observed in cellular cementum were also observed within the acellular cementum. These incremental lines were wider and their degree of calcification was higher.

Induction of cementogenesis by recombinant human osteogenic protein-1 (hOP-1/BMP-7) in the baboon ( Papio ursinus)

Recombinant human osteogenic protein-1 (hOP-1), a member of the bone morphogenetic protein family, was examined for its efficacy in periodontal regeneration. Twelve furcation defects, surgically prepared in the first and second mandibular molars, were treated with bovine insoluble collagenous matrix in conjunction with 0.0 (control), 100 and 500 μg of recombinant hOP-1 per g of matrix. After 60 days of healing, histological and histometric analyses on serial, undemineralized sections cut at 7 μm showed substantial cementogenesis on the exposed dentine of furcations treated with both doses of hOP-1 ( p < 0.01 vs control). Foci of nascent mineralization were seen within the newly deposited cementoid along the coronal areas of hOP-l-treated defects. Within the furcations, there were substantial amounts of residual collagenous carrier, interspersed with a mineralized matrix having histological features of cementum. This mineralized cementum-like material was predominantly deposited around the carrier, and blended into newly formed cementum along the root surfaces. In the apical area, the cementum-like material and the remaining alveolar bony housing were not connected; indeed the two components were separated by a fibrovascular tissue that had numerous features of the periodontal ligament space. Formation and insertion of Sharpey's fibres into newly formed root cementum were also observed. It is likely that the expression of specific cell phenotypes by h0P-1 is regulated, in part, by the extracellular matrix microenvironment, including dentine. Thus, exposed dentine, in the presence of exogenous hOP-1 at the doses tested, may preferentially modulate the expression of the cementogenic phenotype. These findings in a non-human primate show that hOP-1, at the doses tested, induced cementogenesis on surgically denuded root surfaces, indicating a specific function during repair and regeneration of periodontal tissues.

Renal Dysplasia with Secondary Hyperparathyroidism and Loose Teeth in a Young Dog

In a dog with renal dysplasia and secondary hyperparathyroidism, loose teeth resulted from excessive resorption of alveolar bone. Sharpey's fibers, still anchored in the cementum, were lost in the replacing fibrous tissue and few fibers found their way to distant bone fragments. The alveolar bone is the site of predilection for the excessive, generalized resorption of bone in hyperparathyroidism. Clinical radiographic examination of the jaws is a valuable tool in the detection of the disease.

Wound healing in beagle dogs after palatal repair without denudation of bone.

The connection of scar tissue to palatal bone by Sharpey's fibers, after cleft palate surgery, might lead to maxillary growth inhibition. The aim of this study, in beagle dogs, was to investigate the possibility of preventing the development of Sharpey's fibers by means of a modified surgical technique. In group 1, palatal repair according to von Langenbeck, was simulated. In group 2, palatal surgery was performed using a new partially split flap technique. The palates were histologically evaluated 12 weeks after surgery and compared with a control group. In group 1, the scar tissue was firmly attached to bundle bone by means of Sharpey's fibers. In group 2 and in the control group, this kind of attachment was not found; the bone was of the lamellar type. The partially split flap technique had led to the development of vaguely demarcated scar tissue and it had prevented, to a large extent, development of Sharpey's fibers.

Wound Healing in Beagle Dogs after Palatal Repair without Denudation of Bone

The connection of scar tissue to palatal bone by Sharpey's fibers, after cleft palate surgery, might lead to maxillary growth inhibition. The aim of this study, in beagle dogs, was to investigate the possibility of preventing the development of Sharpey's fibers by means of a modified surgical technique. In group 1, palatal repair according to von Langenbeck, was simulated. In group 2, palatal surgery was performed using a new partially split flap technique. The palates were histologically evaluated 12 weeks after surgery and compared with a control group. In group 1, the scar tissue was firmly attached to bundle bone by means of Sharpey's fibers. In group 2 and in the control group, this kind of attachment was not found; the bone was of the lamellar type. The partially split flap technique had led to the development of vaguely demarcated scar tissue and it had prevented, to a large extent, development of Sharpey's fibers.

Poly-(L-Lactic) Acid Membranes in Palatal Surgery in Beagle Dogs: Clinical and Histologic Evaluation

This article reports on the histologic findings from a larger study that was designed to investigate whether the attachment of scar tissue to underlying bone, which is normally found after palatal surgery, can be prevented by using biodegradable poly-(L-lactic) acid membranes. Von Langenbeck's procedure was simulated in 12-week-old beagle dogs without clefts. In one group normal wound healing was allowed. In two groups, membranes were inserted immediately after surgery or 3 weeks thereafter. Sham and control groups were also included. Histologic evaluation was carried out at regular intervals. Reports have been published on other aspects, such as clinical wound healing, contraction and maxillary arch development in beagle dogs following this treatment. After direct implantation of membranes, wound healing was retarded. Disintegration of the membranes started soon after implantation and remaining particles were surrounded by a fibroblastic sheath and a fibrous capsule. At sites where membrane particles persisted, attachment of the scar tissue to the underlying bone by Sharpey's fibers was prevented.

Histological identification of osteocytes in the allegedly acellular bone of the sea breams Acanthopagrus australis, Pagrus auratus and Rhabdosargus sarba (Sparidae, Perciformes, Teleostei)

The bone of advanced teleost fishes such as those of the family Sparidae is said to lack osteocytes or to be acellular. Acellularity has been determined by apparent lack of osteocyte lacunae. This study questions the validity of this criterion. Scanning electron and light microscopy of paraffin and resin sections were used to show that the sides of sea bream mandibles consist of laminar parallel-fibred bone that we call tubular bone, because it contains tubules, and localised regions of Sharpey fibre bone. Osteocytes lie along the walls of tubules that also contain collagen fibril bundles (T-fibres), or in the lumens of tubules that do not contain T-fibres. We show that the osteocytes are derived from osteoblasts. The T-fibre system is different from other fibre systems that have been described. The tubules enclose wide T-fibres (lenticular in cross-section, maximum width about 8 microns) that taper at their ends and continue as thin T-fibres (round in cross-section, about 2 microns wide). The T-fibres originate in the periosteum. In mature tubular bone, spaces of increasing size develop around the osteocytes. Osteocytes are released from the bone matrix and become postosteocytes or bone-lining cells. Secondary bone lines the largest spaces. In Sharpey fibre bone, small osteocytes in small lacunae (about 2 microns wide) are found in columns parallel to the Sharpey fibres. Large osteocytes are found in large round spaces and are much larger than comparable osteocytes in lacunae in the bone of the salmon Salmo salar. We conclude that an absence of visible or conventional osteocyte lacunae does not mean that the cells themselves are absent. There are cells and two types of collagen fibre bundle in the tubules. The cells are osteocytes derived from osteoblasts, and these osteocytes apparently resorb bone with the result that large amounts of bone are destroyed. "Acellular" tubular and Sharpey fibre bone are types of cellular bone that differ from each other and from conventional cellular bone.

An analysis of autograft fixation after anterior cruciate ligament reconstruction in a rabbit model.

Fixation and incorporation of a tendon implanted within the bone pose theoretical as well as practical concerns for the surgeon who treats instability problems of the knee. Understanding the physiology involved in graft-bone incorporation is necessary for the appropriate rehabilitation of patients who undergo anterior cruciate ligament surgery. The purpose of the study was to examine the histologic and biomechanical changes of a semitendinosus autograft reconstruction of the anterior cruciate ligament in a rabbit model at the graft-bone tunnel interface in the femur. The results indicate that by 3 weeks, failure of the bone-graft-bone or construction is through the intraarticular portion of the graft, not as a result of pullout from the bone tunnel. Graft fixation of the bone tunnel occurs by an intertwining of graft and connective tissue and anchoring of connective tissue to bone by collagenous fibers and bone formation in the tunnels. The collagenous fibers have the appearance of the Sharpey's fibers seen in an indirect tendon insertion.

A Study on Three Dimensional Ultrastructural Arrangement of Collagen Fibrils of Compact Bone and Sharpey's Fibers

A Study on Three Dimensional Ultrastructural Arrangement of Collagen Fibrils of Compact Bone and Sharpey's Fibers

Tendon-healing in a bone tunnel. A biomechanical and histological study in the dog.

Our study evaluated tendon-to-bone healing in a dog model. Twenty adult mongrel dogs had a transplantation of the long digital extensor tendon into a 4.8-millimeter drill-hole in the proximal tibial metaphysis. Four dogs were killed at each of five time-periods (two, four, eight, twelve, and twenty-six weeks after the transplantation), and the histological and biomechanical characteristics of the tendon-bone interface were evaluated. Serial histological analysis revealed progressive reestablishment of collagen-fiber continuity between the bone and the tendon. A layer of cellular, fibrous tissue was noted between the tendon and the bone, along the length of the bone tunnel; this layer progressively matured and reorganized during the healing process. The collagen fibers that attached the tendon to the bone resembled Sharpey fibers. High-resolution radiographs showed remodeling of the trabecular bone that surrounded the tendon. At the two, four, and eight-week time-periods, all specimens had failed by pull-out of the tendon from the bone tunnel. The strength of the interface was noted to have significantly and progressively increased between the second and the twelfth week after the transplantation. At the twelve and twenty-six-week time-periods, all specimens had failed by pull-out of the tendon from the clamp or by mid-substance rupture of the tendon. The progressive increase in strength was correlated with the degree of bone ingrowth, mineralization, and maturation of the healing tissue, noted histologically.

Recovery from disuse osteopenia coincident to restoration of muscle strength in mdx mice

The objective of this study was to compare the tibial structure and the strength of the tibia during muscle weakness and after recovery in mdx mice (which demonstrate X-linked muscular dystrophy and subsequent muscle regeneration) and age-matched control mice. The extent of disuse atrophy produced by muscle weakness and recovery following restoration of normal muscle strength could then be determined. The tibiae adjacent to weakened tibialis anterior muscles of 4-week-old mdx mice had significantly reduced radiographic density ( p < 0.05) and cortical thickness ( p < 0.001), and increased porosity ( p < 0.001) compared to age-matched controls, suggesting development of disuse osteopenia. Significantly less force was required to break mdx tibiae than age-matched control tibiae ( p < 0.05). In addition, Sharpey's fiber density was reduced ( p < 0.001), suggesting a weakened attachment of the tibialis anterior muscle to bone. At 12 weeks, during the period of muscle regeneration, mdx tibial cortical thickness ( p < 0.001) and porosity ( p < 0.01) remained significantly lower, but percent calcium and Sharpey's fiber and radiographic densities were significantly greater ( p < 0.001) than in age-matched controls, suggesting that bone mineralization and muscle attachment strength had increased to above normal levels in parallel with recovery of strength by the attached muscle. By 18 weeks, mdx tibial cross-sectional area, cortical thickness, and porosity remained significantly less ( p < 0.001) than normal. Although Sharpey's fiber density was greater than in agematched controls ( p < 0.001) by 18 weeks, mdx tibial percent calcium ( p < 0.005) and Sharpey's fiber density ( p < 0.001) were significantly reduced from levels in 12-week-old mdx animals. There was significantly less deformation of the tibia prior to fracture in mdx than control tibiae at 18 weeks of age, suggesting tibial brittleness. Thus, at the site of attachment of mdx muscle to osteopenic bone, the remodelling which accompanies recovery of muscle strength is atypical, and produces an attachment of greater strength than function appears to require. These observations suggest that data are needed regarding bone mass and muscle—bone attachments in humans with disuse osteopenia, DMD, and other neuromuscular diseases.

Analysis of stress-strain curves in the rat molar periodontal ligament after application of orthodontic force

Previous studies have shown that the mechanical strength of the periodontal ligament decreased markedly after application of an orthodontic force to the rat molars.13 However, an analysis of stress-strain curves obtained from transverse sections of the rat molars has not been made. The present study analyzed the stress-strain curves obtained from the mesial root of the rat mandibular first molar to evaluate the changes of the mechanical properties of the ligament after application of an orthodontic force. An elastic band was inserted between the mandibular first and second molars for 7 days. The maximum shear stress, elastic stiffness, and failure strain energy density were significantly less in the experimental group than in the control group, but the maximum strain was significantly greater. Histologic examinations of the transverse section after mechanical testing showed that the area of the ligament adhering to the mesial surface (compression side) of the socket bone was significantly less in the experimental group. It is suggested that orthodontic forces may cause changes in the constitution of the periodontal collagen, in osteoclastic activity in alveolar bone, and in mineralization patterns of Sharpey's fibers followed by reductions of the mechanical strength of the ligament, particularly on the compression side of alveolar bone.

Periodontal repair or regeneration: structures of different types of new attachment.

The present study details the structural and ultrastructural features of healing events between the regenerated periodontal ligament and the root surface after experimental periodontal disease. Experiments were performed on dogs, and the concept of guided tissue regeneration was tested using resorbable polyurethane membranes. Light microscopy, scanning- and transmission electron microscopy were employed to determine if healing events involve regeneration (ie, process by which the architecture and the function are completely renewed) or periodontal repair (ie, healing of a wound by tissue that does not fully restore the architecture of a part). Regeneration occurred in parts of the roots only if some original cementum remained on the root surface after root planing. Repair was observed if peripheral dentin was removed by root planing as this layer was not reestablished. In areas remote from the base of the defect, new collagen fibrils, synthesized by fibroblasts and oriented perpendicular to the root surface, were spliced with severed ends of Sharpey's fiber bundles of original cementum. If circumpulpal dentin was exposed, intermingling between new fibrils with dentinal matrix fibrils occurred. In areas near the base of the defect, the first event was the formation of a cementoid by a cementoblast monolayer and subsequent formation of intrinsic fibrils oriented parallel to the root surface. Afterwards, the cementoblast monolayer disintegrated and extrinsic fiber bundles became anchored in the new cellular mixed fiber cementum. In these areas, linkage between new cementum and pre-existing tissues always occurred by interfacial intermingling of the fibrils, regardless of whether new attachment occurred at circumpulpal dentin or original cementum.

Periodontal tissue regeneration including cementogenesis adjacent to dentin-bonded retrograde composite fillings in humans

The roots of two incisors were treated by apicoectomy and a retrograde dentin-bonded composite filling. Periapical healing was observed a few months later by radiography. Later, due to root fracture and marginal bone resorption, the apical parts were removed including adjacent periapical bone. A histological and scanning electron microscopic examination of the tissue showed reformation of periodontium adjacent to the composite, including reformation of a lamina dura, inserting Sharpey's fibers and cementum deposited in intimate contact with the composite. This finding is in agreement with previous observations of tissue surrounding retrograde dentin-bonded composite fillings placed in monkeys, indicating that tissue regeneration including cementogenesis may occur on composite material and consequently form a biological closure of the root canal.

Repair process of external root resorption subsequent to palatal expansion treatment

The repair process of external root resorption (ERR) and the role of retention mechanics in enhancing ERR repair were studied on eight Macaca fascicularis monkeys that were divided equally into short- and long-term groups. Six monkeys received palatal expansion appliances, and two received sham appliances. The short-term group received active treatment. The long-term group received additional retention (4 months) and relapse (2 months) treatment periods with biweekly injections of individual vital dye per phase, i.e., procion red H-8B and violet H-3R (80 mg/kg B.W.), respectively. Histomorphologic examinations included scanning electron microscopy, light, and ultraviolet microscopy. The short-term group demonstrated penetrated resorption with pulp exposure at sites with initial deficiency of the protecting odontoblastic layer (apical zone, nutrition canal). The long-term group showed two forms of ERR repair: (1) Nonfunctional retarded repair cementum, comprised of overlapped incremental lines and deprived of extrinsic fibers, was delineated in severe pulp exposure. The pulp/dentin complex showed intense incorporation of procion dye in the dentinal tubuli, conceivably related to a defense response in the form of sclerotic dentin. (2) Functional rapid repair cementum, comprised of discriminated incremental lines mainly of mixed cellular cementum, with a consistent pattern of five sequential phases: the lag phase (14 to 28 days), the incipient phase (14 days), the peak phase (14 to 28 days), the steady phase (42 to 56 days) and the retreating phase (70 days). Sharpey's fibers at functional ERR sites were scarce, never emerging from the dentinocemental junction, and not developing into principal fibers. The pulp/dentin complex showed an increase in pulp stones but no formation of tertiary dentin. The apical area responded by hypercementosis in the form of apical occlusion and a displaced pulp canal. The application of a fixed retention device is recommended in light of accelerated apposition of repair cementum during the retention period. However, increased formation of Sharpey's fibers during the relapse period might suggest a restricted duration in splinting therapy.

The development of a novel implant: induction of a non-rigid and self-renewing anchorage of artificial implants to bone

Artificial implants currently used in orthopaedic surgery and dentistry are anchored to the surrounding bone by rigid mechanical fixation. Long-term studies indicate that the rate of implant failure due to loosening increases steeply after 10 years of function. The loosening is attributed to the micro-movements occurring at the bone implant interface. Non-rigid, self-renewing ligamentous anchorage is nature's solution to the problem of micro-movements. An excellent example of this type of anchorage is the tooth-bone system, where the tooth is anchored to the bone by a fibrous connective tissue. A novel artificial implant, bearing on its surface a unique biological substrate (BS), was designed to induce a ligamentous anchorage of implant to bone. The implant consists of a metallic core to which the BS is bound. The BS is a composite of plastic material and a collagen mesh which is partly incorporated into the plastic material and partly freely extended from its outer surface as artificial Sharpey's fibers. BS fabrication did not affect the capacity of the collagen to withstand non-specific degradation in vitro. Non-weight-bearing implants implanted into the femoral bone of rats induced and maintained a ligament-like tissue up to 4 months. The collagen fibers of the ligament-like tissue were spliced with the artificial BS Sharpey's fibers and were also anchored as Sharpey's fibers into the surrounding bone. Examination of control plastic implants (without the BS) revealed bone formation in close approximation to the implant surface. It is suggested that the novel biological substrate has the capacity to induce and maintain a ligament-like anchorage of implant to bone.