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Biomedical subjects

T J Coward

Publications and source records attributed to T J Coward.

10 recordsLinked to original sources
PubMed2002

Identifying the position of an ear from a laser scan: the significance for planning rehabilitation.

Laser scanning techniques are used to plan the construction of prosthetic ears as dimensional measurements between anthropometric points can be accurately measured on a screen image. The aim of this study was to determine if these techniques could be used to assess the position of ears on the face. Computer-generated images were created from laser scans of 20 subjects. Frames of reference were constructed by locating a series of anthropometric points on the face from which three orthogonal planes were constructed. A central reference point was identified at the intersection of the three orthogonal planes. Dimensional measurements were made between anthropometric points on the ear and the reference planes. The differences between anthropometric points and the reference planes on the left and right sides of the face were small. It was possible to describe the location of points three-dimensionally with respect to a central reference point. The development of frames of reference and a central reference point would appear to offer many advantages in the assessment and description of ear position for patients requiring reconstruction with prostheses.

Adolescent↗
PubMed2001

The contribution of imaging and digitised data to mandibular reconstruction and implant stabilised occlusal rehabilitation: a case report.

Different methods are recommended for the surgical reconstruction of the resected mandible. The advantages for implant stabilised prostheses in restoring the occlusion are recognised but few papers provide adequate data to identify the successful outcome of treatment. The literature is reviewed and the advantages of imaging together with the use of digitised data is highlighted by a case requiring rehabilitation with enhanced planning methods.

Bone Transplantation↗
PubMed2001

A comparison between videotaped and live demonstrations, for the teaching of removable partial denture procedures.

AIM: This study was devised to test the effectiveness of videotaped demonstrations as opposed to live demonstrations, to small groups of undergraduate dental students. The outcome was assessed by comparing the students' understanding of the clinical and laboratory technical stages of the altered cast impression technique, which is used in the construction of removable partial dentures. METHOD: 31 students watched a series of videotaped demonstrations and 30 received a similar series of live demonstrations. The altered cast procedure was divided into 5 distinct stages, each of which was assessed with the aid of agreed criteria, initially by the students and then by 2 staff assessors and these results were compared. The students were subsequently asked to rate how helpful the videotaped or live demonstration had been on a 5-point scale. RESULTS: The live demonstration group showed better agreement between the students' assessment and the assessors' assessment of the quality of the work for the first part of the clinical stage. There was no difference in the groups' assessment of the final outcome of this clinical stage and the subsequent laboratory technical stages. Students who observed the live demonstrations indicated higher scores for its helpfulness in performance of all the stages of the technique, when compared to those who had observed a videotaped demonstration. CONCLUSION: Both teaching methods developed a similar level of understanding of the principles behind the exercise, although the students preferred the live demonstrations. A carefully produced videotaped demonstration can be a useful alternative to a live demonstration in teaching the short and clear cut technique selected for this study.

Chromium Alloys↗
PubMed2000

Laser scanning of the ear identifying the shape and position in subjects with normal facial symmetry.

The objective of the present study was to discover if dimensional measurements of the ear could be determined with a laser scanning technique and whether or not the location of landmarks of the ear could be reliably measured with respect to those on the midline of the face. Computer-generated images were created from laser scans of 20 subjects. Dimensional measurements were made between landmarks on the ear and face. Differences between repeated dimensional measurements of the ear were very small, as were those measurements made between landmarks on the ear to the midline of the face. Differences between dimensions of the left and right ears were observed, but were of a small magnitude. The results suggest that the dimensions of the ear and its position with respect to landmarks in the midline of the face can be reliably measured on normal subjects and that laser scanning is a useful technique for planning and monitoring facial reconstruction of the ear.

Adolescent↗
PubMed1997

Laser scanning for the identification of repeatable landmarks of the ears and face.

OBJECTIVE: To determine whether or not landmarks of the ears and face could be reliably identified using a laser scaning system. DESIGN: A single centre study with two assessors jointly agreeing the siting of the landmarks on the ear on two separate occasions from an original laser scanned image. SETTING: University based research study in London, UK. SUBJECTS: 20 subjects, 11 males, 9 females, aged 16-24 years with normal facial development. MAIN OUTCOME MEASURES: Differences were determined between the locations of landmarks on the two occasions studied. Differences were assessed for the x, y and z co-ordinates of each point. RESULTS: The mean difference between the two sitings of 21 landmarks ranged between 0 and 0.85 mm in the x, y and z axes. With a small number of exceptions, the differences were not statistically significant. The three-dimensional mean differences between the two sitings of each landmark ranged between 1 and 2.5 mm. Coefficients of repeatability ranged between 1.6 and 7.0 mm. CONCLUSIONS: Landmarks of the ears and face from a laser scanned image can be sited consistently by two assessors. Since the landmarks can be located it should be possible to evaluate dimensional measurements of the ear and its position on the face.

Adolescent↗
PubMed1993

Considerations in treatment planning for implant-supported auricular prostheses.

Improvements in planning for the provision of silicone auricular prostheses have been achieved with CT scanning. The analysis of information using a computer workstation has enabled preoperative determination of skull thickness and position of implants in relation to the proposed location of the prosthesis. The technique is of particular value in cases of craniofacial microsomia.

Ear, External↗
PubMedDate not supplied

Fabrication of a wax ear by rapid-process modeling using stereolithography.

PURPOSE: The purpose of this article is to describe an automated technique that creates a mirror-image wax model of the contralateral ear using a rapid prototyping technique, which allows precise positioning and adaptation to the deficient side of the face. MATERIALS AND METHODS: Magnetic resonance images (MRI) are taken of the face and then digitized and reformatted into a 3-dimensional image. The image of the normal ear is extracted, mirrored, and positioned onto the image of the deformed side of the face. The digitized data, when used in conjunction with stereolithography, produces a photopolymerized resin model ear. A model wax ear is created by pouring molten wax into a silicone mold of the resin model ear. RESULTS: A model wax ear of identical dimensions, shape, and internal contouring as the contralateral normal ear is created. The technique allows the undersurface of the model wax ear to be precisely positioned against the surface contours of the deformed side of the face in 1 patient. CONCLUSION: The use of stereolithography from MRI scan data is a suitable technique for producing a model wax ear that fits the deformed side of the face. The 3-dimensional computer image of the face may also be used to plan the position (level and protrusion) of the ear.

Computer-Aided Design↗
PubMedDate not supplied

Results of treatment of 20 patients with implant-retained auricular prostheses.

A prospective study of 20 patients receiving rehabilitation for a missing external ear revealed the failure of three flanged implants in a total of 60 placed for the support of a prosthesis and 10 for retention of a bone-anchored hearing aid. Factors limiting an optimal outcome were health of the cutaneous cuff around the abutments, bonding of the silicone ear to the acrylic-resin substructure, and the ability to minimize disfigurement of a congenitally deformed face.

Acrylic Resins↗
PubMedDate not supplied

Locating angulated abutments: a technical note.

A simple laboratory-made acrylic resin guide offers rapid location of angulated abutments after the healing abutments are removed. An impression recording the relation of the implants to the dental arch enables the choice of abutments to be made in the laboratory. The precise position and angulation of each abutment can be transferred to the mouth.

Acrylic Resins↗