C T Roberts

The University of Manchester, Manchester, England, United Kingdom

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Publications (15)12.66 Total impact

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    C T Roberts, S Richmond
    British journal of orthodontics 06/1997; 24(2):139-47.
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    ABSTRACT: The aim of this study was to compare the diagnostic quality of conventional cephalometric radiographs with that of digital image counterparts. The random error associated with angular and linear measurements recorded on the digital images was greater than on the conventional radiographs. In addition, there was a systematic error producing statistically significant differences in the majority of angular and linear measurements between the digital images and the conventional radiographs. The errors that occurred with some measurements were of sufficient magnitude to be of clinical significance, particularly in a cephalometric situation where a high degree of accuracy is required. It is therefore suggested that, for digital imaging of cephalometric radiographs, a pixel matrix larger than 512 x 512 with more than 64 gray levels is required to maintain the diagnostic quality of the original radiograph.
    The Angle Orthodontist 02/1996; 66(1):43-50. · 1.18 Impact Factor
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    ABSTRACT: Dentists' opinions as to both need for and outcome of orthodontic treatment show wide variation. Within the profession there is an opportunity to reduce subjective bias and standardise criteria by the use of occlusal indices. The results of this study demonstrate that a group of dentists can easily be trained to record the Aesthetic and Dental Health Components of the Index of Orthodontic Treatment Need and the PAR index to a satisfactory level.
    Community Dentistry And Oral Epidemiology 07/1995; 23(3):173-6. · 1.80 Impact Factor
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    ABSTRACT: This study looked at the aesthetic and dental health components of the index of orthodontic treatment need in relation to peer assessment of dental health and aesthetic need (panel of 74 dentists). The dental health component had a Spearmans correlation coefficient of +0.64 and the aesthetic component +0.86 when compared with the mean subjective opinion of 74 dentists. It has been proposed to have three categories for both the dental health and aesthetic components in accordance with consensus opinion. The panel of 74 examiners were more likely to regard aesthetics as a greater need for treatment than dental health.
    British dental journal 06/1995; 178(10):370-4. · 0.81 Impact Factor
  • S Richmond, C T Roberts, M Andrews
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    ABSTRACT: The Index of Orthodontic Treatment Need (IOTN) was used to assess the need for orthodontic treatment before and after treatment, on a systematic sample of 1225 cases. On the whole, full upper and lower fixed appliances brought about a greater improvement in Aesthetics and Dental Health Components compared to other appliance techniques, and were less likely to make the occlusion worse. It was found that certain occlusal traits were more likely to be successfully treated than others. A common problem resulting from treatment was the development of a cross-bite.
    British journal of orthodontics 06/1994; 21(2):175-84.
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    ABSTRACT: The criteria that dentists use to judge the need for orthodontic treatment are not clear. This study investigates variation in dentists' perception of orthodontic treatment need. Seventy-four dentists were asked to assess 320 dental casts in relation to aesthetic and dental health need. The results of this investigation revealed that the panel was divided as what constituted a need for orthodontic treatment on dental health grounds. It is suggested that one method of achieving a more uniform evaluation of orthodontic treatment need is the use of an occlusal index. Until an occlusal index is accepted and used by the profession, the distortion of need and demand for orthodontic treatment by dentists' unequal perceptions will continue.
    British journal of orthodontics 03/1994; 21(1):65-8.
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    ABSTRACT: Prior to 1987, dental practitioners in England and Wales intending to carry out all but the simplest orthodontic treatment within the National Health Service, were required to submit pretreatment study models, details of the orthodontic assessment and the proposed treatment plan to the Dental Estimates Board prior to starting treatment. Models taken at the end of treatment were required by the Board to enable payment to be made. In this pilot study, the acceptability of orthodontic treatment plans used by practitioners working in the General Dental Services was assessed by eight hospital consultants, using information about 40 cases submitted to the Dental Estimates Board in 1987/88. All consultants considered a high proportion of plans to be unacceptable, but agreement between the consultants was variable and some agreed with one another on very few plans. A single scorer used the weighted PAR (Peer Assessment Rating) index to assess the degree of departure from normal occlusion of both pre- and post-treatment models. Using accepted standards, only nine cases were greatly improved (PAR reduction > 70%) and the mean percentage reduction in PAR score was low. Consultant opinion on the appropriateness of treatment planning was not related to the outcome of orthodontic treatment.
    Journal of Dentistry 12/1993; 21(6):355-9. · 3.20 Impact Factor
  • S Richmond, M Andrews, C T Roberts
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    ABSTRACT: A systematic sample of 1010 cases was collected by the Dental Practice Board. The commonest type of treatment involved extraction of the first premolars followed by removable appliances. Treatment duration was on average 1.9 years, one-arch fixed appliances were started in an older age group and two-arch fixed appliance treatment took longer to complete than other appliance types. The best standard of treatment was achieved using upper and lower fixed appliances.
    British journal of orthodontics 12/1993; 20(4):345-50.
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    ABSTRACT: Out of a sample of 1210 orthodontic patients treated within the General Dental Services in England and Wales, a high proportion showed no improvement. Upper and lower fixed appliances had the greatest influence on the outcome of treatment in terms of aesthetics, dental health need and standards. When treatment was analysed according to the appliance used, there were no statistically significant differences in the standard of treatment undertaken by specialist orthodontists and general dental practitioners. Methods for improving British orthodontic standards are considered.
    British dental journal 06/1993; 174(9):315-29. · 0.81 Impact Factor
  • K D O'Brien, W C Shaw, C T Roberts
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    ABSTRACT: This retrospective study was carried out to assess the need for orthodontic treatment and the standard of treatment provided by a sample of 17 hospital-based orthodontic departments. A total of 1630 sets of patients records were collected and analysed for orthodontic treatment need and standard of treatment with the Index of Orthodontic Treatment Need and the PAR index, respectively. The data were analysed with a variant of analysis of covariance using linear modelling techniques. In general terms it appeared that the hospital service provided treatment of a high standard, in terms of dento-occlusal change, to a caseload of patients that were in need of treatment. The effectiveness of treatment provision was influenced by the grade of operator, the choice of treatment methods and by the departmental attitudes and aspirations.
    British journal of orthodontics 03/1993; 20(1):25-35.
  • S Richmond, W C Shaw, C T Roberts, M Andrews
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    ABSTRACT: In orthodontics it is important to objectively assess whether a worthwhile improvement has been achieved in terms of overall alignment and occlusion for an individual patient or the greater proportion of a practitioner's caseload. An objective measure is described that has been validated against the subjective opinions of 74 dentists. Using the weighted PAR Index it was revealed that at least a 30 per cent reduction in PAR score is required for a case to be considered as 'improved' and a change of 22 PAR points to bring about 'great improvement'. For a practitioner to demonstrate high standards the proportion of an individual's case load falling in the 'worse or no different' category should be negligible and the mean reduction should be as high as possible (e.g. greater than 70 per cent). If the mean percentage reduction in PAR score is high and the proportion of cases that have been 'greatly improved' is also high, this indicates that the practitioner is treating a great proportion of cases with a clear need for treatment to a high standard.
    The European Journal of Orthodontics 07/1992; 14(3):180-7. · 1.08 Impact Factor
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    ABSTRACT: The PAR Index has been developed to provide a single summary score for all the occlusal anomalies which may be found in a malocclusion. The score provides an estimate of how far a case deviates from normal alignment and occlusion. The difference in scores between the pre- and post-treatment cases reflects the degree of improvement and, therefore, the success of treatment. Excellent reliability was exhibited within and between examiners (Intraclass Correlation Coefficient, R greater than 0.91). The components of the PAR Index have been weighted to reflect current British orthodontic opinion and is flexible in that the weightings could be changed to reflect future standards and standards currently being achieved in other countries. The PAR Index offers uniformity and standardization in assessing the outcome of orthodontic treatment.
    The European Journal of Orthodontics 05/1992; 14(2):125-39. · 1.08 Impact Factor
  • C T Roberts, G Semb, W C Shaw
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    ABSTRACT: This paper examines the clinical research methodologies used for the evaluation of cleft lip and palate therapies. A survey of clinical reports in the Cleft Palate Journal between 1964 and 1988 revealed that almost all used retrospective methods (96%). The authors examine the merits and biases associated with retrospective evaluation of therapies and compared these to prospective randomized clinical trials. The strengths and weaknesses of clinical trials are discussed in relation to the long-term evaluation of primary surgery in cleft patients. For these to be successful, further work is needed to investigate questions such as sample size, possible predictors of long-term outcome, and improved methods of presurgical assessment. The authors conclude that if the uncertainties associated with the choice of primary cleft surgery are to be resolved, the challenge of multicenter prospective clinical trials must be faced by the various disciplines involved in cleft palate clinical research.
    The Cleft Palate-Craniofacial Journal 05/1991; 28(2):141-9. · 1.24 Impact Factor
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    ABSTRACT: The regional distribution of orthodontic treatment provision through the General Dental Service was examined, with reference to, per capita spending, cost per case and treatment rate; a marked regional variation in these variables was detected. The regional distributions of the specialist orthodontic practitioner and the General Dental Practitioner were calculated; and also exhibited a marked regional variation. The relationships between the regional distributions of manpower treatment rate and spending on orthodontic treatment were calculated. It was found that there were significant relationships between the regional distribution of manpower and treatment rate and per capita spending, but not cost per case. Possible explanations are discussed.
    British journal of orthodontics 06/1989; 16(2):67-74.
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    ABSTRACT: A clinical trial was carried out to evaluate and compare the clinical performance of a visible light-cured material with a chemically cured adhesive. This was used in combination with two types of bracket base. Fifty-two patients entered the trial and 542 bracket bases were placed. The incidence and site of bond failure were recorded. The overall failure rate for the light-cured material in combination with both types of bracket was 4.7% and 6% for the chemical-cured adhesive. There were no significant differences detected between the failure rates for both types of adhesive in combination with either bracket base, and no bracket base/adhesive combination proved superior (p greater than 0.05). When the data were examined in an overall manner, a significantly higher posterior tooth failure rate was detected for all adhesive/base combinations (p less than 0.001).
    American Journal of Orthodontics and Dentofacial Orthopedics 05/1989; 95(4):348-51. · 1.46 Impact Factor