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Biomedical subjects

C E English

Publications and source records attributed to C E English.

At least 19 recordsLinked to original sources
PubMed1995

Hygiene, maintenance, and prosthodontic concerns for the infirm implant patient: clinical report and discussion.

Hygiene techniques and prosthetic maintenance procedures are illustrated for an infirm implant patient who is unable to communicate verbally or in written modes. Potential problems are discussed as they pertain to long-term patients who are in nursing homes, domiciles, or hospital wards. The issue of modifying a prosthesis to enhance the ease of providing oral hygiene care is examined.

Aged↗
PubMed1994

Bar patterns in implant prosthodontics.

An extensive discussion of bar patterns is presented, including historical background, current bar designs, and precision milling concepts. Research that has been done on different bar configurations is discussed along with technical and clinical considerations for various bar pattern designs.

Dental Clasps↗
PubMed1994

Restoration of the maxillary arch with a precision-milled double-bar prosthesis.

When restoring the challenging maxillary arch, no one treatment will serve all patients optimally. An open mind must be maintained, and the prosthetic evolution and creativity will continue. The ideal tooth position for each case should be determined prior to surgery in order to ensure optimum prosthetic results. This presentation and paper discuss the restoration of the maxillary arch. Impressions, soft tissue model, bar pattern, alloy selection, screw seating, and screw-retained suprastructure over infrastructure are presented and illustrated.

Dental Implantation, Endosseous↗
PubMed1993

Mechanical tooth concepts in implant dentistry.

A brief history of mechanical tooth concepts is presented with an update and discussion of the three basic categories of designs presently available. The application of mechanical designs to implant dentistry is covered with a discussion of indications, contraindications, and technical requirements for each of the categories.

Composite Resins↗
PubMed1993

Finite element analysis of four-abutment Hader bar designs.

Three-dimensional finite element analyses were conducted on the four-abutment Hader bar to determine mechanical properties with respect to bar length, stiffener height, and material properties. Three stiffener heights (1, 2, and 3 mm) were analyzed representing a clinical range of usage. Three material types were studied which represent a selection of alloys commonly used clinically. The model consisted of a representative Hader bar of 1.8-mm diameter with a 1-mm inferior stiffener. The ends of the bar were fixed to a 5-mm diameter coping which was attached to a 3.8-mm root form-type implant fixed in a representative block of bone. The bone was modeled as fixed at its distal end to eliminate rigid body motion. A 200 Newton occlusal force was imposed on the mesial bar and a 450 Newton force on the distal bar for the three stiffener heights. The results of these analyses predicted yielding and fracture (failure) for all 1-mm stiffener height and type IV gold alloy cases studied. Stiffener height was found to play a strong role in the adequacy of the overall design as compared with changing material properties in the range of alloy stiffness tested. Factors of safety with respect to static yield strength ranged from 1.44 to 2.12 on the distal portion.

Chromium Alloys↗
PubMed1993

Biomechanical concerns with fixed partial dentures involving implants.

Nine biomechanical factors involved in the design and fabrication of fixed partial dentures incorporating implants are discussed, focusing upon the deleterious effects of leverage, torsion, occlusal overload, and poor oral hygiene. Areas of concern are cantilevers, pier abutments, excessive fixed spans, use and misuse of nonrigid connectors, off-axis loading, occlusal plane to implant height ratio, inadequate support, distribution, and mandibular flexion and torsion.

Biomechanical Phenomena↗
PubMed1993

Implant-supported versus implant-natural-tooth-supported fixed partial dentures.

The use of implants with fixed partial dentures requires that the restorative dentist address a new set of concerns when planning treatment. This paper presents some important issues and evaluates the advantages and disadvantages of each choice, including the decision whether to treat the patient as a totally implant-supported or as a combination case. The special problems of posterior restorations include occlusion, rigid versus nonrigid coupling mechanisms, root intrusion, and screw versus cement retention.

Dental Abutments↗
PubMed1992

Finite element analysis (FEA) studies in 2.5-mm round bar design: the effects of bar length and material composition on bar failure.

The round bar/overdenture prosthesis is commonly used in the restoration of the totally edentulous implant patient. The length of bar span and types of alloys used in clinical cases have raised questions related to beam flexure and its role as a possible etiology of reported clinical failures in cast alloy systems. Three-dimensional finite element analyses were thus conducted on a 2.5-mm round bar for investigation of mechanical performance with respect to failure potential as a function of bar length and bar material property. Specifically, three bar lengths (6 mm, 12 mm, and 18 mm) and three alloy materials were analyzed, representing a clinical range of usage. The ends of each bar were modeled fixed to a 2.5-mm coping which was attached to a 3.8-mm root-form-type implant. The implant was modeled rigidly fixed in a representative block of bone. A 200-N occlusal force was applied to the model, as would be transmitted through an attachment clip, 5 mm in length, for the three respective bar lengths. The results of these analyses suggested possible yielding (or failure) in the 18-mm case. Bar length was found to play a stronger role in the adequacy of the overall design as compared with changing material properties in the range of alloy stiffnesses tested. Factors of safety with respect to static yield strength ranged from 2.82 to 66.46 for the designs evaluated. Fatigue factors of safety ranged from 1.63 to 38.88. A factor of safety of 5 or greater is suggested for the design of round bar systems in order for bar failure to be prevented.

Computer Simulation↗