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At least 127 records · Page 7Linked to original sources
PubMed2002

The treatment of chronic osteomyelitis with a biodegradable antibiotic-impregnated implant.

The use of local antibiotics from a biodegradable implant for chronic osteomyelitis is an attractive alternative. The implant delivers high tissue levels, obliterates dead space, aids bone repair and does not need to be removed. The purpose of this paper is to review our early clinical experience with custom-made calcium sulfate (Osteoset bone void filler) antibiotic-impregnated implants.

Absorbable Implants↗
PubMed2001

Biomechanical properties in titanium implants with integrated maintenance free shock absorbing elements.

Good functional properties are essential in dental implantology. Bio-kinetic elements are imitating dental resilience. In this study a new kind of implants with maintenance free shock absorbing elements will be introduced and their bio-mechanic properties reported. The mobile implant (SIS Inc., Klagenfurt, Austria) is a self-cutting conical screw implant with an integrated bio-kinetic element. The shock absorber is a central part of the implant and a titanium ring closes the shock absorbing unit within the implant. The resilience of the implant was tested by axial and horizontal loading in a special testing unit. Furthermore, a survival test of the elastic titanium ring in the most exposed cervical part of the implant was performed. The region was examined by electron microscopy after 12 million movements in the axial and horizontal direction. A progressive shock absorption was registered during horizontal and axial movements. The maximum movements were 0.06 mm in the axial and 0.16 mm in the horizontal direction. There were seen no signs of material destruction in the electron microscopic analysis. A maintenance-free bio-kinetic implant with progressive shock absorbing qualities was registered.

Biomechanical Phenomena↗
PubMed1996

[Usefulness of selected parameters from the diagnostic laboratory for evaluating absorbed grafting materials].

The results of hematologic, biochemical research and research of clotting system after intraperitoneal implantation of absorbed synthetic threads Dexon S are presented in this work. The research was made on rats of Wistar type. Blood for the research was taken 3, 7, 14, 30 and 60 days after the implantation. Morphology (Ht, Hb, MCH, WBC, the number of platelets), activity of aspartic and alanine aminotransferase and antithrombin activity, concentration of comolete protein and its fraction and concentration of glucose, urea, creatinine and also concentration of ions Na+, K+, Mg2+, Ca2+ and fibrinogen, protein C3 and C4 of complement system as well as kaolin-kephalin time and prothrombin time of plasma were marked. On the basis of the obtained results of the research it was noticed that the used methods of research constitute supplement of biological estimation of absorbed grafting materials.

Absorption↗
PubMedDate not supplied

A clinical and histologic evaluation of implant integration in the posterior maxilla after sinus floor augmentation with autogenous bone, bovine hydroxyapatite, or a 20:80 mixture.

PURPOSE: This study was designed to clinically and histologically evaluate the integration of titanium implants in different grafting materials used for maxillary sinus augmentation procedures. MATERIALS AND METHODS: A total of 21 patients and 36 maxillary sinuses were augmented with (1) autogenous particulated bone from the mandibular ramus, (2) bovine hydroxyapatite (BH) with membrane coverage, or (3) an 80/20 mixture of BH and autogenous bone. The grafts were allowed to heal for 6 to 9 months prior to placement of microimplants for histology and standard implants for prosthetic rehabilitation. After another 6 months of healing, when abutments were connected, the microimplants were retrieved for histologic and morphometric analyses. The outcome of the standard implants was clinically evaluated after 1 year of loading. RESULTS: The mean bone-implant contact was 34.6 +/- 9.5%, 54.3 +/- 33.1%, and 31.6 +/- 19.1% for autogenous bone, mixture of 20% autogenous bone/80% BH, and 100% BH, respectively. The corresponding values for the bone area parameter were 37.7 +/- 31.3%, 39.9 +/- 8%, and 41.7 +/- 26.6%. The BH area was found to be 12.3 +/- 8.5% and 11.8 +/- 3.6% for 20% autogenous bone/80% BH and 100% BH, respectively. There were no statistically significant differences for any parameter between any of the groups. After 1 year of loading, 6 of the 33 implants placed in autogenous bone grafts, 2 of the 35 implants placed in the BH/autogenous bone mixture, and 2 of 43 implants placed in BH were lost. There were no statistically significant differences between any of the groups. DISCUSSION: The histomorphometric analysis showed no differences between the 3 groups, indicating that autogenous bone graft can be substituted with bovine hydroxyapatite to 80% or 100% when used for maxillary sinus floor augmentation. The effect of adding autogenous bone remains unclear but may allow for a reduction of the healing time. CONCLUSION: The results from this clinical and histologic study indicate that similar short-term results can be expected when using autogenous bone, BH, or a mixture of them for maxillary sinus floor augmentation and delayed placement of dental implants.

Absorbable Implants↗
PubMed1998

[Troublesome radiologic changes after reconstructive fixation of the anterior cruciate ligament with resorbable interference screws].

The authors report worrisome radiological changes which were noted after implantation of absorbable interference screws in ligamentoplasty at the knee joint. Seventeen screws were implanted between September 1995 and July 1996, in eleven patients (average age 27) who were operated upon for chronic anterior knee instability. They underwent a modified Kenneth Jones procedure using autografts with absorbable interference screws (Acufex in 2 cases and Bio-interférix in 9 cases). Significant enlargement of bone tunnels and bony sclerosis of their edges were noted in every patient, but without any modification in the positioning of the graft. No clinical instability was observed in any of the patients, with one to two years follow-up. Publications on this topic are scarce except for one author who reported enlargement of bone tunnels after using bone-patellar tendon-bone allografts. Resorption of absorbable screws probably induces a marked inflammatory reaction, with radiological changes reminiscent of those sometimes observed after tendon allografts. Although the radiological changes reported here may not affect the graft fixation, the authors have reverted to using metallic interference screws.

Absorption↗
PubMed1992

Computed tomography treatment planning in IR-192 brachytherapy in the head and neck.

Brachytherapy dose prescription and treatment planning lag behind the state-of-the-art for external beam therapy. As altered fractionation of external beam therapy improves patient outcome in head and neck cancer, there will be an increased need to compare the two radiotherapy techniques. Currently, implant techniques and dose prescription documentation are not uniform, dose prescription to a target volume is subjective, and implant quality is poorly understood and not routinely assessed. All contribute to a lack of scientifically rigorous brachytherapy clinical trials. Studies designed to combine tumor imaging and dosimetry data are important in the evolution of brachytherapy treatment planning. Head and neck implants, which often require nonparallel, arching, or looping source carriers for all but small tumors in order to encompass the target volume adequately, were used to evaluate the clinical utility and feasibility of computed tomography as a treatment planning tool in brachytherapy. Following placement of plastic afterloading tubes under general anesthesia, orthogonal radiographs with dummy sources in the afterloading tubes are obtained as customary for source localization. With the patient in the same position, axial CT scans are obtained with the dummy seeds still in place for treatment planning. The implant physician, using data from the pre-treatment diagnostic CT scan, outlines target areas on sequential images creating a 3-dimensional target volume. By superimposing anatomic data with isodose curves one can objectively define implant parameters important in clinical trials analysis. These include minimum target absorbed dose, implant uniformity, and treatment to target volume ratio. The results of the first 10 patients are presented and implications of these data regarding the analysis of implant technique, implant quality, and implant optimization are discussed. The technique as performed is laborious but practicable in the clinical research setting of head and neck implant. Further research efforts should improve, simplify, and objectify brachytherapy and hasten the time when rigorous multi-institutional brachytherapy trials will be reality.

Adult↗
PubMed1991

Effect of intracanalicular collagen implants on the absorption of topically applied sodium fluorescein.

Absorbable intracanalicular collagen implants were placed in both canaliculi of one eye of nine human volunteers. The other eye served as a control. Twenty-four hours later 2% sodium fluorescein was placed into both conjunctival sacs. Serial corneal fluorescein concentrations were measured with a scanning ocular fluorophotometer from 2 to 90 min after fluorescein administration. The mean corneal fluorescein concentration averaged over all time points was greater in 7 of 9 eyes with collagen implants compared to unimplanted controls. When the data from each subject were analyzed collectively, the mean corneal fluorescein concentration in the implanted eyes (1,218 micrograms/ml +/- SEM 83) was significantly greater (p less than 0.001) than the mean concentration in the control eyes (823 micrograms/ml +/- SEM 83). The use of absorbable intracanalicular collagen implants may increase the bioavailability of topically applied ocular solutions.

Absorption↗
PubMedDate not supplied

Scleral implants: an historical perspective.

Scleral implants are made of absorbable or nonabsorbable materials. One category of absorbable materials consists of donor tissue, either autogenous (fascia lata, plantaris gracilis tendon) or from cadavers (dura mater, sclera, fascia lata). A second category includes gelatin, reconstituted collagen, absorbable gut, fibrin, blood plasma, air, and sodium hyaluronate; of these, specially prepared gelatin seems to be the most useful. Nonabsorbable implant materials have proven more practical than absorbable implants. Solid silicone rubber is currently the most popular scleral implant material. It is soft, easy to handle, and well tolerated. Expandable implants, either temporary or permanent, are used in the form of a silicone balloon filled with liquid. Silicone sponge, also widely used, has the advantage of great softness. However, hydrogels seem to be the ideal scleral implants. The only one commercially available is Refojo's MAI implant. It is very soft and is not damaged by sutures, has a smooth surface, is molded in several sizes and shapes, and has small pores that microorganisms cannot penetrate. When saturated with a water-soluble antibiotic before implantation, this implant releases the antibiotic postoperatively for a longer time than any other implant material. Finally, surgical adhesives are useful when the sclera is too thin or weak to tolerate sutures. The best adhesive available seems to be isobutyl cyanoacrylate.

Biocompatible Materials↗
PubMed2001

Single stage surgery combining transmucosal implant placement with guided bone regeneration and bioresorbable materials.

The aim of the present clinical study was to test whether peri-implant bone defects can successfully be filled with bone by applying bioresorbable materials for guided bone regeneration (GBR) procedures in conjunction with implants in the transmucosal healing position. Three women and 7 men ranging in age from 32 to 68 years (median 54.5) needed tooth replacement with dental implants. Eight to 14 weeks following careful tooth extraction, implants of the ITI Dental Implant System were placed at the extraction sites. At this time, all implants presented dehiscence defects of the alveolar bone partly exposing the rough titanium plasma sprayed (TPS) surfaces. GBR procedures were performed using deproteinized bovine bone mineral (Bio-Oss) as a membrane-supporting material and a bioresorbable collagen membrane (Bio-Gide) as a barrier. The membranes and the flaps were adjusted to fit around the necks of the implants, thus leaving the implants extending transmucosally into the oral cavity. Clinical measurements were taken at 6 sites around each implant (mesio-buccal, buccal, disto-buccal, disto-lingual, lingual, mesio-lingual) using a calibrated periodontal probe. These included: i) defect depth measured from the shoulder of the implant to the first bone-to-implant contact, ii) infrabony defect component measured from the bone crest to the first bone-to-implant contact, iii) defect width measured from the crest to the implant body in a direction perpendicular to the long axis of the implant. The Wilcoxon Matched Pairs Signed Rank Test was applied to detect differences over time. At baseline, the mean defect depth per patient amounted to 3.6 mm (Standard Deviation 1.6 mm, range 1.8-6.8 mm). The deepest extensions of the defects were located at the buccal aspects (mean 7.8 mm, SD 1.9 mm). At re-entry, the mean defect had decreased to 2.5 mm (SD 0.6 mm). This difference was statistically significant (P < 0.01). Initially, in 62% of sites the depth ranged from 0-3 mm, in 23% it ranged from 2-4 mm, and in 15% it amounted to more than 6 mm. Six to 7 months later, at re-entry, 95% of sites were 3 mm and less in depth and 5% ranged from 4-6 mm. Defect resolution, as assessed by the amount of coverage of the initially exposed rough implant surface, reached a mean value of 86% (SD 33%). One hundred percent resolution was accomplished at 8 out of 10 implants, 60% at one and 0% at another implant. The tissue at the latter implant showed signs of infection and inflammation during the healing phase. It is concluded that bioresorbable materials in GBR procedures at transmucosal implants can lead to successful bone regeneration into peri-implant defects.

Absorbable Implants↗
PubMed2002

Craniofacial reconstruction with computer-generated HTR patient-matched implants: use in primary bony tumor excision.

The aim of this clinical series is to report the effectiveness and safety of using computer-generated alloplastic hard tissue replacement (HTR) implants for the reconstruction of large defects of the cranio-orbital region when combined with simultaneous bone tumor excision. Seven patients who had large nonmalignant bony lesions of the anterior cranial vault and orbit underwent simultaneous bony excision and reconstruction with preoperatively fabricated custom alloplastic implants. Preoperatively, a 3D computed tomography (CT) scan was obtained from which an anatomical model was fabricated. On the anatomical model, the predicted amount of bone excision was performed. The defect in the model was then used to create an alloplastic (HTR polymer) implant for reconstruction and surgical placement. At the time of surgery, the implant was secured into position with either metal or resorbable plates and screws. In cases where the frontal sinus was in proximity to the implant, it was either cranialized and covered with a pericranial flap or obliterated with hydroxyapatite cement. All computer-generated implants required some modification intraoperatively due to a larger amount of bony excision than was preoperatively planned. This was accomplished by modifying the sterile back-up of the implant as an addition to the original implant or completing reconstruction of the bony defect with hydroxyapatite cement. All patients have healed uneventfully with a minimum of 1 year follow-up (average, 2.6 years). In all cases, excellent contours have been maintained and all patients have remained infection-free. In the management of large benign bony tumors of the cranio-orbital region, simultaneous reconstruction with custom implants fabricated from porous, hydrophilic HTR polymer can be preoperatively fabricated based on an estimate of the subsequent bony defect. The successful use of this approach depends on a favorable tissue quality of the recipient site, a generous preoperative estimate of the amount of bone that will be resected so that the implant is adequate, intraoperative techniques of expanding the implant reconstruction, and intraoperative methods to assure a partitioning of the implant from the frontal sinus.

Absorbable Implants↗
PubMed2003

Imaging of periimplant bone levels of implants with buccal bone defects.

The aim of the present study was to use four different methods to evaluate three radiographic techniques for their accuracy in assessing the marginal periimplant bone levels at implants with buccal bone defects in an experimental setting. Twenty-four implants were placed in the mandibles of six adult beagle dogs with substantial buccal bone defects, which were augmented by bone particles with and without resorbable membranes. After healing for 5 months, (1) periapical radiographs, (2, 3) reformatted images in (2) sagittal and (3) coronal planes from axial computer tomography (CT) scans and (4) direct magnification images (DIMA) were made and compared with histometric analysis of bone levels. Two values were used for comparison: (i) the lingual bone level and (ii) the true bone level calculated as a mean value from the lingual and the buccal bone levels of all histologic sections of each implant. Metric evaluation of periapical radiographs, sagittal reformation of CT scans and DIMA showed that the results were close to the histometrically assessed lingual bone level, while the true bone level was significantly lower and not reflected by any of the imaging modalities. Coronal reformation showed that there was significant overestimation of the lingual and underestimation of the buccal bone level when compared with histometric values. It is concluded that assessment of bone level and bone regeneration in implants with buccal bone defects remains problematic, and data from periapical radiograms tend considerably to overestimate the bone anchorage of these implants.

Absorbable Implants↗
PubMed2001

The preliminary evaluation of HAP + TCP composite material biodegradation after implantation in muscular tissue of rats.

Ceramic biomaterials based on calcium phosphates have a special position among modern implantation material in osteosurgery. Non-reabsorbable hydroxyapatite (HAP) and reabsorbable tricalcium phosphate are the most popular calcium phosphate ceramics. The appropriate ratio of these two compounds should result in forming the gradually reabsorbable implants, overgrowing with the bone tissue which mechanical strength should not be negatively affected. The aim of this work was to evaluate a local tissue reaction and the HAP + TCP composite resorption rate as compared with HAP, after implantation in a muscle tissue of rats. On the basis of carried macroscopic and microscopic evaluations, it can be stated that the new HAP + TCP composite had high biocompatibility and were gradually reabsorbed. This enables faster overgrowing the implant with tissue.

Absorbable Implants↗
PubMed1993

[Resorbable implant materials in retinal detachment surgery. Initial animal experiment studies].

In detachment surgery after a mechanically stabile chorioretinal scar is at present full scleral indentation no longer mandatory. Following these considerations absorbable scleral implants have been developed and tested in an animal model. Cylindrical pieces of absorbable composite-material with a diameter of 5 mm were sutured as radial scleral explants in 18 rabbits. The composite material consisted of a polyglactin-polydioxanon ratio 7:1. The absorption time for polyglactin is 60 days, for polydioxanon 180 days. The explants produced initially in ultrasonographically measured buckle height between 3.2 and 4.0 mm. The clinical and ultrasonographical follow up study demonstrated a continuous decrease of buckle height. Two weeks after implantation there was a medium height of 2.0 mm after five weeks a medium elevation of 0.5 mm was found. Histopathological examinations showed incidence of a slight resorptive inflammation in the area of the buckle which was not evident after 12 weeks. No scleral infiltration or scleral thinning was found. The promising results have justified controlled clinical trials with the absorbable material which might allow to combine the advantages of silicone sponge explants (precise localization) with those of scleral buckles by inflatible balloons (reversibility).

Absorption↗