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At least 19 recordsLinked to original sources
PubMed1990

[Preparation and insertion of computer-designed ceramic inlays].

The CEREC-system allows the production and insertion of ceramic inlays chairside in one visit. For this purpose an optical impression of the cavity is made, the inlay is designed on the computer screen and ground from a ceramic bloc. The inlay is bonded to the tooth using acid etch technique and a luting composite. Finally occlusal adjustment is performed. The technical prerequisites and the clinical procedure are presented and discussed in comparison to other tooth coloured inlay systems.

Dental Cavity Preparation↗
PubMed1992

Three dimensional imaging and computer-designed prostheses in the evaluation and management of orbitocranial deformities.

Three dimensional images reconstructed from two dimensional CT scans allow improved analysis of complex orbitocranial bony deformities. This evaluation may be useful in patients with defects resulting from trauma, tumor, congenital abnormalities, or developmental disorders. Diagnosis, surgical management, and long-term follow-up evaluation may be aided by improved understanding of bony contour and volume analysis. Computer designed prostheses can be fabricated to precisely match bony defects and may be used as an alloplastic implant or as a model to aid intraoperative contouring of an autogenous bone graft. The limitations of three dimensional imaging include artifacts in the reconstructed images, increased radiation exposure, and increased cost. The technology is still evolving and the indications and benefits remain undefined at the present time.

Adolescent↗
PubMed1988

Computer-designed prostheses for orbitocranial reconstruction.

Three-dimensional imaging is an adjunct to preoperative evaluation and surgical management in some patients with complex anatomic defects of various etiologies. Deformities defined by conventional computerized tomography can be viewed as accurate three-dimensional images calculated from the original scan. The images are viewed on a high-resolution video monitor and can be photographed for a permanent record. A computer-controlled milling device can use these data to fabricate prostheses. The prostheses aid reconstructive surgery through use as an alloplastic implant, as a template to fashion autogenous bone grafts, or as a model for tissue removal. We have utilized three-dimensional imaging in combination with computer-assisted prosthesis manufacture in six patients with complex orbitocranial deformities. Four patients have undergone reconstructive surgery with satisfactory results and no complications thus far. The use of computer-designed prostheses adds a new aspect to orbitocranial reconstructive surgery that facilitates increased accuracy in the correction of anatomic defects.

Adolescent↗
PubMed1989

A custom-designed computer network for a dental clinical school.

A local area computer network has been designed and implemented to service predominantly the patient-related administrative needs of the Westmead Dental Clinical School. The appropriate software has been developed in-house over a period of time and introduced as the complexity and volume of the tasks increased and as more sophisticated hardware became available. The present arrangement utilizes NEC APC III and NEC APC IV computers with ACSinet networking hardware added to an OMNInet system. Primary functions include the management of extensive patient waiting lists (up to 16,000), treatment lists and laboratory work flow, as well as the provision of a wide range of related statistical information. Wordprocessing is a large scale daily activity. More specialized secondary functions include monitoring of patients allocated to dental students, support of the management of appointments, recalls, mailing lists and some specific research projects including data collection for a quality assurance programme. The network functions separately but simultaneously alongside an extensive hospital-wide VAX cluster and has greatly simplified the handling and management of a vast array of data essential to the management and evaluation of the treatment provided in the Dental Clinical School.

Computer Systems↗
PubMed1991

Computer design of bioactive molecules: a method for receptor-based de novo ligand design.

The design of molecules to bind specifically to protein receptors has long been a goal of computer-assisted molecular design. Given detailed structural knowledge of the target receptor, it should be possible to construct a model of a potential ligand, by algorithmic connection of small molecular fragments, that will exhibit the desired structural and electrostatic complementarity with the receptor. However, progress in this area of receptor-based, de novo ligand design has been hampered by the complexity of the construction process, in which potentially huge numbers of structures must be considered. By limiting the scope of the structure-space examined to one particular class of ligands--namely, peptides and peptide-like compounds--the problem complexity has been reduced to the point that successful, de novo design is now possible. The methodology presented employs a large template set of amino acid conformations which are iteratively pieced together in a model of the target receptor. Each stage of ligand growth is evaluated according to a molecular mechanics-based energy function, which considers van der Waals and coulombic interactions, internal strain energy of the lengthening ligand, and desolvation of both ligand and receptor. The search space is managed by use of a data tree which is kept under control by pruning according to the energy evaluation. Ligands grown by this procedure are subjected to follow-up evaluation in which an approximate binding enthalpy is determined. This methodology has proven useful as a precise model-builder and has also shown the ability to design bioactive ligands.

Algorithms↗
PubMed1990

A computer designed graph for administration of atracurium by i.v. infusion.

A bi-exponential mathematical computer model was used to develop a guidance graph for atracurium infusions. The model permitted variation in infusion rates, in pharmacokinetic parameters and in "effect" thresholds. Systematic experiments revealed a relationship between the rate of recovery from a fixed bolus loading dose and the most appropriate initial infusion rate. This relationship was expressed as a guidance graph or "ready reckoner". The quality of guidance was assessed in 50 anaesthetics, given consecutively. In 39 patients optimal myoneural block for surgery was maintained for the duration of the infusion without adjustments or supplementary bolus doses. The mean operating time was 92 min and the mean duration of infusion was 59 min.

Adult↗
PubMedDate not supplied

Absorbed dose resulting from a specially designed computed tomography technique for examination of the urinary bladder.

The absorbed spatial dose distribution resulting from a specially designed CT protocol for examination of the urinary bladder has been investigated with TLD rods in a body phantom containing tissue equivalent material. The CT examination consisted of scout view and both pre- and postcontrast scan series with 5 mm slice thickness and 5 mm unscanned intervals between successive scans. Cross-sectional dose distribution for one scan in the plane of the ovaries was measured as well as the dose profile for one scan along a line through the ovary parallel to the axis of rotation. Based on these measurements, the dose resulting from the whole CT examination was calculated, both with contiguous and noncontiguous scans. The ovarian dose was calculated for different positions of the ovaries in relation to the scanned area. The absorbed dose varied between 8.3 mGy and 9.7 mGy with the actual technique used. When contiguous scans with the same thickness were taken, the ovarian dose increased with a factor from 1.7 to 1.9. The dose resulting from the CT protocol of the urinary bladder was of the same magnitude as absorbed dose resulting from urography. When the diagnostic gain from a precise definition of tumor extent was taken into account, the dose resulting from the CT protocol was judged acceptable.

Female↗
PubMed1992

Computer-designed inlays after 5 years in situ: clinical performance and scanning electron microscopic evaluation.

Eight mesio-occlusodistal adhesive inlays, fabricated from ceramic blocks using a computer-aided design/machining method, were reexamined after 5 years of clinical service. The inlays wre evaluated according to modified US Public Health Service criteria. The results indicated excellent clinical performance, with eight Alfa ratings for wear, recurrent caries, and color match, and five Alfa and three Bravo for marginal discoloration and marginal integrity. Under scanning electron microscope, 81.0% of the tooth-cement interfaces and 84.1% of the cement-inlay interfaces were rated continuous at the occlusal margin. Axially, 73.6% of the tooth-cement interfaces and 87.0% of the cement-inlay interfaces were rated continuous. Although this long-term investigation revealed good clinical performance of the inlays, improvements in the ceramic structure and its properties, the cavosurface design, and the luting composite resin were recently introduced to further optimize quality.

Ceramics↗
PubMed1991

The computational design of test compounds with potentially specific biological activity: histamine-H2 agonists derived from 5-HT/H2 antagonists.

The previously proposed models for the recognition and activation of 5-HT and histamine-H2 receptors, which were employed to explain the antagonist activity of LSD at both of these receptors, as well as the selective antagonism for H2 receptors by SKF-10856 and 9,10-dihydro-LSD, are used herein to design a compound to test the H2-receptor model. The design strategy attempts to construct a compound with potentially selective H2 agonism. The design scheme maintains features which were previously used to explain selective recognition of SKF-10856 and 9,10-dihydro-LSD as well as reintroduces the chemical features proposed to be responsible for H2 activation. The existence of the H2 recognition and activation features in the proposed compound is verified, in a previously proposed model, by computational studies of the molecular electrostatic potentials and shifts in the tautomeric preference.

Drug Design↗
PubMed1979

Computer design synthesis of a below knee-Syme prosthesis.

A detailed design synthesis analysis of the BK Syme prosthesis is provided, to determine the socket's cutout orientation size and shape, cutout fillet shape, socket wall thickness distribution and the reinforced fiber distribution in the socket wall, for a minimally stressed structurally safe lightweight prosthesis. For analysis purpose, the most adverse socket loading is obtained at the push-off stage of gait; this loading is idealised as an axial in-plane loading on the bottom edge of the circular cylindrical socket shell whose top edge is considered fixed. Finite element stress analysis of the socket shell (with uniform and graded wall thickness) are performed for various orientations of the cutout and for various types of corner fillets. A lateral cutout with a streamline fillet is recommended. The wall material (i.e., thickness) distribution is determined so as to minimise the stresses, while ensuring that the wall material's stress limits are not exceeded. For such a maximally-stressed lightweight socket shell, the panels in the neighbourhood of the cutout are checked to ensure that they do not buckle under their acquired stresses. A fiber-reinforced laminated composite socket shell is also analysed, to recommend optimum variables in orientations and densities of reinforcing fibers.

Ankle↗