Biomedical subjects

Brendan J J Scott

Publications and source records attributed to Brendan J J Scott.

5 recordsLinked to original sources

PubMed2005

A study to compare the oral health impact profile and satisfaction before and after having replacement complete dentures in England and Scotland.

OBJECTIVE: To assess the oral health impact profile (OHIP) on edentulous subjects in Scotland and England who needed to have their dentures replaced, and to determine whether any change in the subjects' assessment of their original and replacement dentures impacted on oral health related quality of life parameters. BACKGROUND: The loss of all teeth may impact on functional activities. The OHIP is an instrument used to measure subjects' perception of the social impact of oral disorders on their well being. METHODS: A total of 58 edentulous subjects were studied. Subjects completed the OHIP-14 questionnaires before and after being provided with a set of replacement complete dentures. They also assessed specific features of the upper and lower dentures. Responses were recorded on a Likert scale. RESULTS: For many subjects, the responses in the before treatment questionnaires were at the lower end of the Likert scale, indicating that there were no major impacts on oral health related quality of life parameters. There were significant improvements in four of the 14 OHIP parameters assessed after treatment. With the new dentures, subjects expressed improved satisfaction, particularly for the lower prosthesis. There were no major differences between the responses of the subjects in Scotland and England. CONCLUSION: For this group of edentulous subjects, although they may need dentures to be replaced after a period of wear, this does not necessarily have significant social impacts. For this reason the provision of new dentures did not result in major changes to the OHIP.

Denture, Complete↗

PubMed2003

The distal extension base denture.

The distal extension base denture may be indicated in situations in which the edentulous area to be restored is without a terminal abutment tooth. There may be significant challenges in providing a prosthesis with sufficient support and retention to make it comfortable without damaging the intra-oral tissues. This can be a greater problem in the mandible as the denture-bearing area is usually much smaller than in the maxilla. This paper considers how distal extension removable prostheses can be designed to restore edentulous spaces.

Dental Clasps↗

PubMed2002

Remote noxious stimuli modulate jaw reflexes evoked by activation of periodontal ligament mechanoreceptors in man.

The purpose of the study was to investigate whether jaw reflexes evoked by selective stimulation of periodontal ligament me canoreceptors are susceptible to modulation by remote noxious stimulation. Experiments were performed on 10 volunteer subjects. Skin surface recordings were made from the jaw-closing masseter muscle. The subjects activated the muscle to approximately 10% of maximum by biting on a rubber impression of their molar teeth while they received visual feedback of the electromyogram (EMG) of the muscle. Reflexes were produced by the application of gentle mechanical stimuli to an upper central incisor tooth. The stimuli were in the form of 'ramp and hold' forces with a 5 ms rise-time and a 1.5 N plateau which lasted 350 ma. The resulting reflexes were recorded both under control conditions and while the subjects received a remote noxious stimulus (immersion of a hand in water at 3 degrees C). In all 10 subjects, the stimuli produced a single period of inhibition of masseteric activity (latency, 12.8 t 04 ms; duration, 18.1+/-1.3 ms; means +/- S.E.M.), which was usually followed by a period of increased masseteric activity. The period of inhibition constituted a downward wave in full-wave rectified, averaged signals. The integrals of such waves were significantly smaller (by 17+/- 6.5 %; P = 0.027; Student's t test) when the reflex was evoked during remote noxious stimulation rather than under control conditions. As such reflexes are beLieved to play a modulatory role during normal oral function this finding maybe relevant to disorders of mastication associated with pain.

Adult↗

PubMedDate not supplied

A comparison between computerized tomography, magnetic resonance imaging, and laser scanning for capturing 3-dimensional data from an object of standard form.

PURPOSE: The study's aim was to compare dimensional measurements on computer images generated from data captured digitally by 3 different methods of the surfaces of a plastic cube of known form to those obtained directly from the cube itself. MATERIALS AND METHODS: Three-dimensional images were reconstructed of a plastic cube obtained by computerized tomography (CT), magnetic resonance imaging (MRI), and laser scanning. Digital calipers were used to record dimensional measurements between the opposing faces of the plastic cube. Similar dimensional measurements were recorded between the cube faces on each of the reconstructed images. The data were analyzed using a 2-way ANOVA to determine whether there were differences between dimensional measurements on the computer images generated from the digitization of the cube surfaces by the different techniques, and the direct measurement of the cube itself. RESULTS: A significant effect of how the measurements were taken (ie, direct, CT, MRI, and laser scanning) on the overall variation of dimensional measurement (P < .0005) was observed. Post hoc tests (Bonferroni) revealed that these differences were due principally to differences between the laser-scanned images compared to other sources (ie, direct, CT, and MRI). The magnitude of these differences was very small, up to a maximum mean difference of 0.71 mm (Cl +/- 0.037 mm). CONCLUSION: All 3 methods of imaging would be of value in further studies, not only for the fabrication of complex shapes such as prosthetic ears, but also for other facial prostheses.

Analog-Digital Conversion↗

PubMedDate not supplied

A comparison between computerized tomography, magnetic resonance imaging, and laser scanning for capturing 3-dimensional data from a natural ear to aid rehabilitation.

PURPOSE: To compare dimensional measurements on computer images generated from data captured digitally by 3 different methods to those obtained directly from natural ears and ear casts, so as to determine the optimal method of creating a computer-generated ear image. MATERIALS AND METHODS: Magnetic resonance imaging (MRI) was used to obtain 3-dimensional (3D) data images of the normal ears of 14 subjects. Computerized tomography (CT) and laser scanning (LS) were used to obtain 3D data images from stone casts of the same ears. Dimensional measurements were recorded on 2 occasions between anthropometric landmarks on the subjects' natural ears, casts of the ears, and reconstructed ear images obtained by CT, MRI, and LS. The intraclass correlation coefficients and coefficients of repeatability were calculated. The means of the 2 measurements for each of the dimensions were analyzed using 2-way analysis of variance to determine whether there were differences between the methods of data collection. RESULTS: The intraclass correlation coefficients indicated that dimensions could be reliably measured on the natural ears, casts, and CT, MRI, and LS images. The coefficients of repeatability were all of a small magnitude in relation to the overall dimensions studied. No statistical differences existed between the various sources of data (P = .866) (i.e., direct, cast, CT, MRI, and LS). CONCLUSION: The 3 methods of imaging have generally resulted in dimensional measurements on the reconstructed images that are similar to those of the original source. These are considered appropriate for manufacturing 3D models that can be used to fabricate a prosthesis. However, other factors may also be important, such as shape, contour, and internal form, and these require further investigation.

Calibration↗