[Implantation design and the bone around the implantation. Comparison between 2 screw implantations in the animal experiment].
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Animals↗
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The Choyce Mark VIII anterior chamber implant: primary and secondary implantation compared.
The author only started primary Mark VIII implantation in 1970, and has only a modest total of 50 cases at this time. Therefore it is premature to draw too many conclusions when comparing this small series with secondary implantation going back over 20 years and covering approximately 1200 years. However the following tentative conclusions are drawn: 1. When confronted with pre-existing aphakia (particularly unilateral) the visual and psychological results of secondary Mark VIII implantation are excellent over a wide spectrum of indications and ocular states. It is a very adaptable and versatile implant--a true "Implant for all Seasons" as Clayman has said. 2. Primary Mark VIII implantation shows considerable promise, particularly when allied to a well-thought-out and carefully-executed microsurgical technique as devised by Tennant. The author is performing more and more primary implantations and regards second eyes as a very favorable indication.
Adult↗
Stress analysis of single-tooth implants. I. Effect of elastic parameters and geometry of implant.
Five different implant materials and three different geometries of ankylosed single-tooth implants were investigated. The stress distributions within and around the implants were determined by finite element analysis. Results show that the optimal combination of implant material and geometry can reduce implant and alveolar stresses by a factor of three when compared to an arbitrary implant design.
Alveolar Process↗
Silicone implant arthroplasty of the great toe. A review of single stem and flexible hinge implants.
One hundred sixty-five feet were reconstructed with the single stem silicone implant, including patients with hallux regidus, hallux valgus due to degenerative and osteoarthritic joint changes, hallux valgus secondary to rheumatoid arthritis and patients with previous unsuccessful "bunion" procedures. Preoperative pain and intolerance to shoe wear were relieved in the great majority of patients. The amount of correction of the hallux valgus angle was directly related to the preoperative deformity. Infection occurred in 2 patients, and inflammatory reaction to the implant occurred in one patient. One hundred five feet were reconstructed with a flexible hinge implant; 94 of the feet had joints destroyed by rheumatoid arthritis. Dramatic improvement in the hallux valgus angle resulted in these feet which had relatively severe preoperative deformities. No implant fractures were recorded. The present survey of our cases, and experiences reported by others, encourage the use of these implants by surgeons who follow the suggested indications, surgical technique, and follow up care.
Adolescent↗
Effects of cyclophosphamide treatment before implantation on the development of rat embryos after implantation.
After treatment of pregnant rats 24 h before implantation with a single injection of cyclophosphamide (20--80 mg/kg), a dose-dependent increase in resorption was observed at term but no malformed fetuses could be found. The lowest cyclophosphamide dose that caused 100% resoprtion was 60 mg/kg. Somite number and wet weight indicated retardation of about 24 h during organogenesis. Determination of the time of implantation revealed that the developmental retardation in treated embryos was not due to delayed implantation. At implantation, 24 h after cyclophosphamide treatment, a significant and dose-dependent decrease of the cell number of blastocysts was found. Embryo transplantation experiments showed that early cyclophosphamide treatment interfered with the subsequent development of both the embryo and the mother. The decidual reaction seemed to be more affected by the treatment than the embryos. Most teratologists hold that mouse embryos after treatment in the preimplantation period either die before implantation or survive to term without being malformed. The present study, however, proves that the reaction of drugs at this early stage of pregnancy is more complex than is generally assumed.
Animals↗
The influence of functional use of endosseous dental implants on the tissue-implant interface. II. Clinical aspects.
Functional and non-functional endosseous dental implants were clinically compared in beagle mandibles for up to one year post-operatively. Differing biomechanical conditions led to clinical differences between functional and non-functional implants. Typical clinical tests, however, did not always reveal detailed histological differences between implant-tissue interfaces of functional and non-funcional implants.
Alveolar Process↗
[Prosthetic principles in endosseous implantation (I) and implantation-based dentures (II)].
The prosthetic principles in intraosseous implantation and of the implanted replacement are surveyed and an indication is given of the important prosthetic indications. The significance of proper positioning of the implant and shaping of the implanted replacement are specially dealt with.
Dental Implantation, Endosseous↗
[Subdiaphragmatic pacemaker implantation of pacemakers - results of 1150 implantations].
Permanent pacemaker are presently used on patients with chronic disease of the cardiac conduction system, with recurrent Adams-Stokes attacks, and with bradycardia. 1865 pacemakers have so far been implanted in the unit for special thoracic surgery in the University of Heidelberg from 1965 to 1978. In 1.150 (or 61%) patients the pacemaker was implanted using the subdiaphragmatic method. A lower transverse pericardiotomy was performed and the battery was located in the rectus abdominis sheath. In the remaining 715 (or 39%) patients, the electrodes were introduced transvenously and implanted in the endocardium. The battery unit in this case was located beneath the pectoral muscle. The transvenous approach was the method of choice until 1971; from that time onward the subdiaphragmatic approach gradually replaced it as the method of choice. Between 1971 and 1978 80% of the pacemakers were implanted directly into the myocardium whereas only 20% were introduced transvenously. The subdiaphragmatic method completely eliminates the frequent complications of the transvenous approach, such as dislocation of electrodes and others so that it now is our method of choice.
Diaphragm↗
Experimental scleral buckling with a soft xerogel implant. I. Properties of poly(hydroxyethyl acrylate) compared with gelatin and other swelling implants.
Scleral buckling can be obtained with insoluble hydrophilic polymers that are implanted in the dry state (xerogels, which then expand to a predetermined size by imbibing tissue fluids. Absorbable gelatin, nonabsorbable poly(hydroxyethyl methacrylate) (PHEMA), and poly(glyceryl methacrylate) (PGMA), have been implanted as xerogels in scleral buckling procedures. Gelatin, PHEMA, and PGMA are soft when hydrated, but are hard and brittle in the dehydrated state. However, poly(hydroxyethyl acrylate) (PHEA) is soft not only in the dehydrated state. However, poly(hydroxyethyl acrylate) (PHEA) is soft only when hydrated but also when dehydrated. Dry PHEA can be carved easily to shape and size, and because it is soft it could be very useful for operations on thin, weakened sclera. We have implanted PHEA intrasclerally and suprasclerally in rabbit eyes. Tolerance of PHEA appears to be as good as that of other materials in clinical use. We have impregnated PHEA and gelatin implants with antibiotics to achieve prolonged antibiotic delivery to the surgical site. When dried impregnated gels were assayed for antibiotic activity in agar plates with Sarcina lutea, both gels displayed high but rapidly decreasing activity.
Acrylic Resins↗
The influence of functional use of endosseous dental implants on the tissue-implant interface. I. Histological aspects.
The tissue-implant interfaces of functional and non-functional endosseous dental implants were compared histologically for up to one year post-operatively. Nonmineralized connective tissue zones (a "fibrous capsule") existed in all functional interfaces. Direct, or nearly direct, bone apposition to implants occurred in non-functional interfaces. The origin of this result and its significance in dental implantology is discussed.
Alveolar Process↗
A high-modulus polymer for porous orthopedic implants: biomechanical compatibility of porous implants.
A high-modulus polymer, polysulfone, was evaluated as a porous bone implant material. The bone ingrowth into canine cortical pellets of sintered polysulfone particles was assessed by microradiography and histology. The shear strength of the porous polysulfone-bone interface was determined by push-out and pull-out tests of cortical and trochanteric implants, respectively. Results indicated that the bone ingrowth into porous polysulfone specimens proceeded in such a fashion as to mimic the normal repair at the site. Mechanical testing of cortical and cancellous implants revealed that the interfacial shear strength of the porous polysulfone-bone composite was similar to that achieved using porous metals.
Biocompatible Materials↗
Endolymphatic sac valve implant surgery. II: The unidirectional inner ear valve implant.
A unidirectional inner ear valve implant was developed to direct excess endolymph out of the inner ear in the hydropic state (Ménière's disease) into the mastoid cavity. A detailed technical description of the valve implant is presented as well as some technical aspects of the valve implant based on the surgical anatomy of the endolymphatic sac.
Ear, Inner↗
[Anesthesia in pacemaker implantation. Experiences in 935 cases of anesthesia for the implantation or revision of a cardiac pacemaker].
Observations during 935 anesthesias for implantation or revision of permanent pacemakers are presented. Using different methods of anesthesia we found the light halothane anesthesia introduced by inhalation to be best, provided that only atropine was used for premedication. Applying this method we saw asystolies or ventricular fibrillation in 3% of all cases--3 patients (i.e. 0.4%) died in tabula. Tachycardia (2.4%) occuring mostly during the introduction period were successfully treated by verapamil or practolol. Hypotension (5.4%) mostly took place in the course of anesthesia after implantation of the pacemaker. This depression may be due to a normalisation of the enhanced stroke volume whedication with pethidine or induction with propanidid was followed by comparatively more complications such as exitus letalis (2% resp. 1.5%), cardiac arrest (6.5% resp. 9%) and hypotension (24% resp. 10.5%). Regional anesthesia did not bring specific advantages. The good experiences with soft halothane anesthesia for implantations or revisions of pacemakers include 125 high risk patients (ASA classification IV to VII).
Anesthesia, General↗
Effects of acute X-irradiation on pre-implantation embryos and on the implantation reaction in the mouse.
Pregnant mice were treated on the 1st, 2nd, and 3rd day of pregnancy by a single dose of 300 R X-rays. Uterine dissections at day 6 p.c. topographically revealed decrease of the implantation sites from 9.67 per female in the controls to 8.00 in females irradiated on day 1, to 6.63 in females irradiated on day 2, and to 7.00 in females irradiated on day 3 p.c; Among a number of 22 implantations after irradiation on day 1, 19 after irradiation on day 2 and 11 after irradiation on day 3, however no living embryo could be detected on histological examination. The degree of damage as indicated by the total resorptions was highest (94,7%) after irradiation on day 2 p.c., and lowest (31,8%) after irradiation on day 1 p.c. Since the decidual cell reaction was either unaffected or only slightly reduced after irradiation on day 2 p.c. as indicated by cytomorphological criteria and the alkaline phosphatase reaction, not maternal effects but direct effects only of the irradiation on the embryo must account for embryonic deaths.
Animals↗
Stress analysis of single-tooth implants. II. Effect of implant root-length variation and pseudo-periodontal ligament incorporation.
This study delineates the effects of varying the root length as well as incorporating a soft pseudo periodonal ligament on the overall stress distribution for each of five different implant materials and one implant design.
Carbon↗
Baseball implant. A method of secondary insertion of an intraorbital implant.
A surgical technique for secondary emplacement of an orbital implant is described in which a spherical implant encased in a scleral homograft is placed in the orbit through a transconjuctival incision and sutured to the superior part of the periosteum.
Conjunctiva↗
A chronically implantable catheter-tip micromanometer (JSI 0400) that can be calibrated after implantation.
This paper describes a catheter-tip micromanometer for chronic left ventricular pressure measurements which can be calibrated in the animal after implantation. The calibration curves are linear, both in vitro and in vivo. Good zero-stability is reached after 1 week of implantation. The duration of function of the device is 3 to 6 months.
Animals↗
Vapor-deposited carbon-coated tooth root implants: preliminary evaluation of a stylized tooth implant system in dogs.
The results of this preliminary evaluation of a tooth implant model combining a stylized tooth root design and a thin, highly biocompatible microporous carbon coating, although tentative, add support to the feasibility of developing a statisfactory system for the immediate replacement of selected teeth in healthy bone.
Alveolar Process↗