The Radiographic Assessment of Posterior Interproximal Dental Caries: A Longitudinal Analysis

Strang, Denise Margaret (1990) The Radiographic Assessment of Posterior Interproximal Dental Caries: A Longitudinal Analysis. MSc(R) thesis, University of Glasgow.

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The aim of this study was to investigate the changes in radiographic scores of individual interproximal tooth surfaces over the three-year period of a double-blind anti-caries dentifrice clinical trial. Six dentifrices were employed in the trial. For each of three fluoride levels studied, pastes were formulated with and without the addition of zinc citrate. In this trial, 3005 Lanarkshire schoolchildren enrolled, and bitewing radiographs were taken at baseline and 1, 2 and 3 years later. These were read cross-sectionally and the interproximal surfaces of all posterior teeth scored. The radiographic changes over the four examinations were classified into five groups: (a) surfaces which had a score of 'zero' at all four examinations; (b) surfaces which 'Progressed'; (c) surfaces which 'Reversed'; (d) surfaces which remained 'Stable' and (e) surfaces which were 'Borderline'. Only data which fulfilled certain selection criteria were included in the analysis. Surfaces which had an 'illogical' radiographic combination were re-read longitudinally. In addition, X-rays from surfaces which had a controversial classification were also re-read. The effects on the radiographic changes of (1) dentifrice fluoride concentration (1000, 1500 and 2500 ppm F as MFP); (2) dentifrice zinc citrate content (0 or 0.5 % (w/w)); (3) sex of the volunteer, and (4) the initial radiographic score at baseline examination, were investigated using X2 tests and Generalised Linear Interactive Modelling (GLIM). A significant increase in the proportion of surfaces which remained radiographically sound with increasing dentifrice fluoride content was obtained. A similar decrease in the proportion of surfaces which 'Progressed' was also obtained. Analysis of the data in terms of the baseline radiographic score, showed that only those surfaces which had an initial radiographic score of 'zero' had significant fluoride dose-responses. The addition of zinc citrate to the dentifrices had no effect on the proportions in each category. Females were shown to have fewer surfaces which 'Progressed' than males. Although the classification of radiographic combinations can never be entirely objective, the benefits of longitudinal consideration of these data has been demonstrated.

Item Type: Thesis (MSc(R))
Qualification Level: Masters
Keywords: Dentistry
Date of Award: 1990
Depositing User: Enlighten Team
Unique ID: glathesis:1990-78068
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 30 Jan 2020 15:41
Last Modified: 30 Jan 2020 15:41

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