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Results for “Absorbable Implants”

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At least 127 records · Page 7Linked to original sources
PubMed1994

Tissue-implant interface at an absorbable fracture fixation plug made of polylactide in cancellous bone of distal rabbit femur.

The tissue-implant interface at a self-reinforced poly-L-lactide (SR-PLLA) expansion plug implanted in distal rabbit femoral cancellous bone was studied histologically, histomorphometrically, and microradiographically in 35 rabbits during consolidation of a transverse transcondylar osteotomy fixed with the SR-PLLA expansion plug. The absorbable plug for internal fixation of fractures and osteotomies measured 4.5 mm in diameter and 30 mm in length and had an expandable distal locking blade system. The femoral specimens were harvested in groups of 5-10 rabbits after a follow-up time of 3, 6, 12, and 24 weeks. The intact contralateral femur served as a control. Vigorous osteogenic response to the implant was already observed at 3 weeks postoperatively, and the osteoid surface fraction at 24 weeks was still significantly higher than in the unoperated contralateral femur. Incomplete union of the osteotomy seemed to result in increased fibrous tissue formation at the tissue-implant boundary. No signs of degradation of the SR-PLLA was observed within the entire follow-up period. The number of inflammatory cells at the tissue-implant interface was low. Consequently, the short-term biocompatibility of the implant was deemed acceptable. Clinical application of the expansion plug is being planned.

Animals↗
PubMed1999

Comparison of bioabsorbable and bioinert membranes for guided bone regeneration around non-submerged implants. An experimental study in the mongrel dog.

The aim of this clinical investigation was to evaluate the effect of guided bone regeneration around non-submerged implants using different barrier membranes. Five adult mongrel dogs were used in this investigation. After having all premolars extracted and implant osteotomies performed in the regions of the former premolars, buccal bone defects were created. Subsequently, 3 implants were placed and the defects treated with 1 of the following 3 modalities: a) guided bone regeneration using an expanded polytetrafluoroethylene membrane, b) guided bone regeneration using a bioabsorbable membrane made from a synthetic copolymer of glycolide and lactide and c) no membrane application. Following implant and membrane placement, the mucoperiosteal flaps were repositioned and tightly sutured around the neck of the implants allowing for a non-submerged healing. After a healing period of 6 months, the animals were sacrificed and the specimens processed for histologic evaluation. The clinical pre-treatment defects between the different treatment groups were not statistically different (bioinert membrane group: 4.9 mm; control group: 4.8 mm; bioabsorbable membrane group: 4.5 mm). The remaining histological defects after 6 months of healing amounted to approximately 2.5 mm in the bioinert membrane group, 5.7 mm in the control group and 6.0 mm in the bioabsorbable membrane group. A significant difference was observed between the bioinert membrane group and the other 2 groups. The mineralized bone-to-implant contact in the bioinert membrane group was 51.5%, in the control group 46.3% and in the bioabsorbable membrane group 37.5%. The values between the bioinert membrane group and the bioabsorbable membrane group were statistically different. The results of this study indicate that bone regeneration with bioinert e-PTFE membranes around non-submerged implants is possible. The utilized absorbable polyglycolic/polylactid membrane did not show any bone regenerative effect and the results did not differ from the control group without membrane application.

Absorbable Implants↗
PubMedDate not supplied

A gelatin coated collagen-polyglycolic acid composite membrane as a dural substitute.

We designed a new biodegradable composite membrane for use as a dural substitute. This membrane is composed of polyglycolic acid (PGA) mesh, collagen sponge, and gelatin sponge. Collagen layers are attached on both sides of the PGA mesh. One side of the membrane is coated with freeze-dried gelatin to prevent tissue adhesion. We examined the mechanical properties of the membrane and evaluated its efficacy in vivo by implanting it into dogs. When the mechanical properties of the membrane were measured under wet conditions, tensile strength and resistance against cutting by a suture were approximately 20 N/cm and 13 N, respectively, which are adequate for a surgical material. In the in vivo experiment, our dural substitute was implanted into six adult beagle dogs to repair a 25 x 15 mm defect in the dura mater. Two dogs each were killed at 2 and 4 months after implantation and two were observed over 6 months. At 4 months after implantation, the implanted dural substitute was almost absorbed and a fibrous membrane resembling native host dura had regenerated at the site. No foreign body reaction or significant adhesion to the cerebral cortex was observed. These results indicate the clinical potential of our novel dural substitute.

Absorbable Implants↗
PubMed1997

[A biomechanical study on the bone repairing ability of recombinant human bone morphogenetic protein-2-coral composited artificial bone].

To improve bone repairing ability of coral, recombinant human bone morphogenetic protein-2 (rhBMP-2)-coral composited artificial bone was obtained by combining coral with rhBMP-2 in this experiment. The composite was implanted into rabbit calvarial critical-size defects and coral alone was implanted as control. The bone repairing ability was assessed by radiography, histology and biomechanics. The results showed that implants were absorbed gradually after they was implanted into the defects. In the meantime, the new bone was formed and the mechanical strength was reinforced uninterruptedly in bone defect regions. At 12 weeks, the implants were replaced completely by bone, and the mechanical strength was entirely restored. These suggest that the composite possess a superior bone repairing ability and may be one of the most perfect bone graft substitutes currently available.

Animals↗
PubMed1995

[Absorbable SR-PGA implant in orthopaedics: preliminary results of treatment of fractures].

This article reports preliminary results of treatment in 33 patients with 36 cancellous bone fractures using absorbable rods and screws of self-reinforced polyglycolide (SR-PGA). Plaster cast was used postoperatively for 3 weeks. All fractures but one lateral ankle fracture were fixed until healed without displacement. All of them healed at six weeks after trauma. No wound infection and fluid accumulation occurred. This new device is an ideal implant for fixation of cancellous bone fracture.

Adolescent↗
PubMed1988

Influence of nonbiologic implants on laminectomy membrane formation in dogs.

The effects of various surgical implants, spinal cord hypothermia, and glucocorticoid administration on formation of the laminectomy membrane were evaluated in 32 preconditioned chondrodystrophoid dogs. Modified dorsal laminectomies and full-length durotomies, from T12 to L1, were performed on all dogs. Dogs were allotted to 2 groups. Group-1 dogs (n = 20) were further allocated to 4 subgroups (a, b, c, and d) consisting of 5 dogs each. Group-1a dogs received no implant, group-1b dogs had absorbable gelatin sponges implanted, group-1c dogs had absorbable gelatin films implanted, and group-1d dogs had absorbable gelatin sponges and absorbable gelatin films implanted. Daily neurologic examinations permitted correlation of neurologic dysfunction with secondary spinal cord compression in those dogs in which it developed. The influence of these implants on laminectomy membrane formation and dural healing was assessed by gross and microscopic evaluation of transverse sections of the vertebrae and spinal cord after euthanasia of one member of each subgroup at 1, 2, 4, 8, and 16 weeks after surgery. Group-2 dogs (n = 12) were further allotted to 3 subgroups (a, b, and c) consisting of 4 dogs each. One dog in each group-2 subgroup underwent the same surgical procedures described for the group-1 subgroups (ie, 4 procedures/group-2 subgroup). The additional effects of 3 conventional supportive techniques (selective regional spinal cord hypothermia, glucocorticoid administration, or spinal cord hypothermia and glucocorticoid administration) on laminectomy membrane formation and on immediate postoperative recovery were examined in groups 2a, 2b, and 2c, respectively. Neurologic examinations were performed daily until this time. All dogs in group 2 were euthanatized 1 week after surgery for gross and microscopic examination of transverse sections of the vertebrae and spinal cord. Qualitative histopathologic effects of the different implants and supportive techniques on formation of the laminectomy membrane were determined. Statistical analysis of the degrees of secondary spinal cord compression was performed in group-1 dogs by measuring and comparing ratios of the vertical to the horizontal diameters of the transverse spinal cord sections from locations within (T12 to L1) and out of (T11, T11-12, L1-2, and L2) the region of surgical intervention. The vertical/horizontal diameter ratios measured from transverse sections from T11 to L2 in size-matched, untreated control dogs formed the standards for a mean roundness index of the spinal cord in the various anatomic locations of the vertebral column.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1999

Periodontal repair in dogs: effect of rhBMP-2 concentration on regeneration of alveolar bone and periodontal attachment.

The objective of this study was to evaluate the effect of recombinant human bone morphogenetic protein-2 (rhBMP-2) concentration on regeneration of alveolar bone and cementum, and on associated root resorption and ankylosis. Contralateral, critical size, supra-alveolar, periodontal defects were surgically produced and immediately implanted with rhBMP-2 in an absorbable collagen sponge (ACS) carrier in 8, young adult, male, beagle dogs. 6 animals received rhBMP-2/ACS (rhBMP-2 at 0.05, 0.10, or 0.20 mg/mL; total construct volume/defect approximately 4.0 mL) in contralateral defects following an incomplete block design. 2 animals received rhBMP-2/ACS (rhBMP-2 at 0 and 0.10 mg/mL) in contralateral defects (controls). The animals were euthanised at 8 weeks post-surgery and block sections of the defects were collected for histologic and histometric analysis. Supra-alveolar periodontal defects receiving rhBMP-2 at 0.05, 0.10, or 0.20 mg/ml exhibited extensive alveolar regeneration comprising 86%, 96%, and 88% of the defect height, respectively. Cementum regeneration encompassed 8%, 6%, and 8% of the defect height, respectively. Root resorption was observed for all rhBMP-2 concentrations. Ankylosis was observed in almost all teeth receiving rhBMP-2. Control defects without rhBMP-2 exhibited limited, if any, evidence of alveolar bone and cementum regeneration, root resorption, or ankylosis. Within the selected rhBMP-2 concentration and observation interval, there appear to be no meaningful differences in regeneration of alveolar bone and cementum. There also appear to be no significant differences in the incidence and extent of root resorption and ankylosis, though there may be a positive correlation with rhBMP-2 concentration.

Absorbable Implants↗
PubMed2001

[Carboxymethylcellulose hydrogel-filled breast implants. Our experience in 15 years].

The author reports 15 years of laboratory and surgical experience with the use of breast implants pre-filled with carboxy-methyl-cellulose gel which he has used since 1984. Laboratory tests and results are presented. The author has undertaken a retrospective analysis of 380 clinical cases since 1984. He concludes that there is a future role for breast implants containing a non-toxic, visco-elastic and biodegradable filling gel in conjunction with the manufacture of increasingly reliable implant linings.

Absorbable Implants↗
PubMed2000

Do your membranes have enough space?

Space is a critical requirement of guided bone regeneration using membrane techniques. This paper discusses the role space may play in the use of GBR in conjunction with osseo-integrated implants.

Absorbable Implants↗
PubMed2002

The effect of therapeutic irradiation on LactoSorb absorbable copolymer.

Bioabsorbable implants continue to gain popularity in providing temporary internal fixation due to their many advantages over metallic internal fixation. Coincident with the presence of internal fixation devices, it may be necessary to use radiotherapy to treat tumors. While metal implants can alter the distribution of the radiotherapy beam, bioabsorbable polymer implants are, essentially, tissue equivalent. This ionizing irradiation, in sufficiently high dose, can affect polymers through chain scission and cross-linking and accelerate the hydrolysis of absorbable polymers. However, little is known about the effects of therapeutic doses on such materials. This study exposed LactoSorb (Biomet, Inc., Warsaw, IN) absorbable copolymer to doses of x-ray irradiation in a clinically relevant manner, in vitro, with individual doses of 2 Gy administered five days per week for up to eight weeks, yielding a total cumulative dose of up to 80 Gy. Specimens were tested both mechanically and for inherent viscosity. Overall, the LactoSorb specimens withstood exposure to the irradiation exceedingly well, providing empirical evidence of the suitability of this material for temporary internal fixation when subsequent radiotherapy in the region is probable.

Absorbable Implants↗
PubMed2004

[Research on carboxymethyl chitosan acting as the adjuvant for implantable degradable microspheres].

As a kind of biomaterial, carboxymethyl chitosan (CMC) has excellent biodegradable and bioacceptable capabilities using. This study was aimed to probe into the feasibility of CMC to prepare the implantable sustained release Ciprofloxacin Hydrochloride (CPX) microspheres(MS), and to go further into the pharmaceutic technology, the morphology and the characteristics of in vitro release of the microspheres. First, we prepared the microspheres by emulsification and cross-linking technology. Then, scanning electron microscopy (SEM), infrared spectrum (IR) and differential thermal analysis (DTA) were used to detect the structure and morphology of the MS. The in vitro release of CPX/CMC-MS and the CPX content of the MS were detected through continuous-flow releasing system. We found that the structure and morphology of the MS were affected by the conditions of preparation such as emulsification and cross-linking temperature, ionic strength and stirring speed, that the releasing time of CPX was more than 7 days, and that the releasing behaviors of the microspheres conformed to the Higuchi model. So we drew the conclusions that CMC could be used as a kind of absorbable and implantable adjuvant for sustained release, the technology of emulsification and cross-linking was proved to be feasible, stable and simple.

Absorbable Implants↗
PubMed1990

A histomorphological study on self-reinforced polyglycolide (SR-PGA) osteosynthesis implants coated with slowly absorbable polymers.

A total of 150 osteotomies of rabbits' distal femur were fixed with absorbable self-reinforced polyglycolide (SR-PGA) rods coated with slowly absorbable polymers. In order to reduce the degradation rate of the SR-PGA construction rods were coated with n-butyl-2-cyanoacrylate, polydioxanone (PDS), poly-beta-hydroxybutyrate (PHBA), or poly-l-lactide (PLLA). Biocompatibility and the rate of biodegradation were evaluated in histological, histomorphometric, microradiographic, and oxytetracycline labeling studies. PDS, PHBA, and PLLA coatings showed good biocompatibility although there were scattered fluid accumulations around the rod in each group. Cyanoacrylate coating seemed to inhibit cartilage regeneration and cause the formation of considerable amount of connective tissue around the implant. The PGA core of the rod had totally degraded in 24 to 36 weeks in each coating group. Cyanoacrylate and PDS coatings were not detectable after 6 weeks while PHBA and PLLA coatings were still observed after 48 weeks. There were five (14%) non-unions in the cyanoacrylate coating group, one (3%) in the PHBA coating group caused by a purulent infection and none in the PDS and PLLA coating groups.

Absorption↗
PubMed2000

Clinical and histological results of septoplasty with a resorbable implant.

BACKGROUND: The use of a resorbable implant connected with septal cartilage would facilitate external septoplasty, offering mechanical stability until the cartilage fragments heal. OBJECTIVE: To study the histological and clinical results of septoplasty with a resorbable implant (polydioxanone [PDS; Ethicon, Norderstedt, Germany]) in conjunction with cartilage. DESIGN: To provide histological information in 5 rabbits, PDS foil was implanted into the outer ear in conjunction with an artificial cartilage defect. Observations were made at 2, 5, 10, 15, and 25 weeks. Resorption of the implant was investigated, including the time to complete elimination. In addition, septoplasty with PDS foil was performed on 71 patients with severe septal deformities. Surgery consisted of excision of the quadrilateral cartilage and division into straight fragments, which were sutured to the PDS foil and replaced as a free graft. SETTING: Ear, nose, and throat department of the General District Hospital Steyr, Steyr, Austria. RESULTS: Histological examination showed that the foil remained unchanged for at least 10 weeks and was completely resorbed after 25 weeks with minimal remaining scar tissue. Newly formed cartilage developed bordering the cartilage defect. In the clinical study, all patients experienced varying degrees of improvement in nasal blockage. No immediate or long-term complications occurred. CONCLUSIONS: The use of PDS foil in connection with cartilage facilitates surgical correction of severe septal deformities, additionally providing support for the nasal dorsum. The histological examination showed that no inflammatory or foreign body reaction occurred. Cartilage regeneration was even found. The foil was completely resorbed within 25 weeks, avoiding the long-term complications that occur with other artificial implants.

Absorbable Implants↗
PubMed2004

Delayed biodegradation of a meniscal screw.

A biodegradable polylactide meniscal screw was removed 32 months after the original meniscal repair. It was then subjected to gel permeation chromatography and was found to have retained 64.7% of its original molecular weight. Although it is obvious that the manufacturers of biodegradable implants have succeeded in producing materials that retain their strength long enough to allow tissue healing, the question arises as to the true biodegradation time of the same implants.

Absorbable Implants↗
PubMed2005

Maxilla sinus grafting with marine algae derived bone forming material: a clinical report of long-term results.

PURPOSE: Autogenous bone grafting continues to be considered the gold standard for sinus grafting. For the past 15 years the author has used an alternative graft material and followed-up the input/output statistic of implants to evaluate if this material results similar to the autogenous bone graft. Histomorphometric evaluations of graft materials show how much new bone is formed and if the graft material is resorbed. MATERIALS AND METHODS: In our study we used a marine derived carbonated red algae that is chemically converted into hydroxyapatite (HA). This material is distributed worldwide as the Communauté Européenne approved material AlgiPore (Dentsply Friadent, Mannheim, Germany), as the US Food and Drug Administration approved material C GRAFT (The Clinician Preference LLC, Golden, CO), and the Russian approved material AlgOss (Unexim Co, Moscow, Russia). A total of 209 sinus grafts were performed on 118 patients who presented with a severely resorbed maxillary alveolar process with 1 to 5 mm (mean, 3.6 mm) of remaining bone. The available bone was comparable to Class D bone as described by Simion et al. After 6 months implants were placed and 6 months later the implants were loaded. RESULTS: From September 5, 1990, to September 1, 2004, the author performed 209 sinus grafts on 118 patients. The longest observation period of loaded implants in this study is 156 months (13 years). Implant loss was 27 out of 614 loaded implants (4.4%), showing a survival rate of 95.6%. Smokers and women over 50 are included. Although AlgiPore/C GRAFT/AlgOss (ACA) undergoes a resorption process, we found only 14% volume loss after 6.4 months compared with 49.5% after 6 months when autogenous bone was used. CONCLUSION: This retrospective study of over 14 years shows once again that the sinus lift procedure with grafting of the sinus floor and subsequent implant placement is a proven method. This 14-year longitudinal study shows that the marine derived HA material ACA in a mixture with approximately 10% autogenous collector bone and blood or platelet rich plasma is able to enhance enough new bone in 6 months to allow implant osseointegration after 6 more months with a high implant survival rate.

Absorbable Implants↗
PubMed2003

Instrument for extraction socket measurement in immediate implant installation.

The aim of the present study was to create an instrument and a computer program for measurement of extraction sockets and for planning of the immediate replacement of teeth using screw-shaped dental implants. Ten titanium screw-shaped Osteofix Dental Implant System implants (Osteofix, Oulu, Finland) were immediately installed after extraction in nine patients, four women and five men (age 17-62 years). The measurements of fresh extraction sockets were taken at six points (mesio-buccal, buccal, disto-buccal, disto-lingual, lingual and mesio-lingual) using an instrument created by the author. The area of no contact between bone and dental implant was 11-40% (mean 31%, SD 9%), calculated by computer program. If less than 30% of the implant surface area would be in contact with the bone, immediate replacement was abandoned because sufficient primary stability could not be achieved. Guided bone regeneration was promoted by covering the implant and bone defect with deproteinized bovine bone mineral (Bio-Oss, Geistlich AG, Wolhusen, Switzerland) and bioresorbable collagen membrane (Bio-Gide, Geistlich AG), fixed in place with resorbable pins (Resor Pin, Geistlich AG). After 6 months a considerable, statistically significant (P < 0.05) defect reduction of 90% (SD 7%) was noted. It was concluded that an instrument and a computer program created for extraction socket measurement are useful in some borderline cases when there is lack of bone and the success of one-stage implantation is doubtful.

Absorbable Implants↗