The Barry Project--a three-dimensional assessment of occlusal treatment change in a consecutively referred sample: the incisors

A closer look at General Dental Service orthodontics in England and Wales. II: What determines appliance selection?

AIM

To elucidate factors that influence choice of appliance type in General Dental Service (GDS) orthodontics in England and Wales.

METHOD

Records were obtained for 1527 cases, representing a systematic 2 per cent sample of GDS cases completed during 1990-91. Evaluation involved Discriminant Analysis to find the most influential factors in appliance choice. Factors considered included patient and practitioner characteristics, and features of the malocclusion as assessed by Occlusal Indices.

RESULTS

Full data were available for 1217 cases. 24 per cent of treatments included use of dual- and 26 per cent single-arch fixed appliances. Appliance choice was predictable in 55 per cent of cases. Older patients, orthodontically qualified practitioners, high Peer Assessment Rating score at start, permanent dentition, lower grades of the Dental Health Component of the Index of Orthodontic Treatment Need at start, and practitioners with high gross earnings from orthodontics, all tended to be associated with more frequent use of fixed appliances.

CONCLUSIONS

Possession of a diploma or membership in orthodontics was associated with more frequent use of both dual- and single-arch fixed appliances. Better appliance selection, and thus more effective treatments in the GDS, may result from a greater availability of practitioners with formal postgraduate training in orthodontics.

A closer look at General Dental Service orthodontics in England and Wales. I: Factors influencing effectiveness

OBJECTIVE

To evaluate factors influencing effectiveness in General Dental Service (GDS) orthodontics.

DESIGN

Retrospective analysis of systematic 2% sample of GDS (England and Wales) cases.

METHOD

Records of cases were collected during 1991. Assessment involved occlusal indices and data from National Health Service forms for 1,411 cases. Multivariate analyses were used with Peer Assessment Rating Index (PAR) score at Finish as the outcome indicator.

RESULTS

Dual arch fixed appliances: achieved lower Finish PAR scores than other appliances; only 1.5% of the variance was explained, by treatment time and Dental Health Component of the Index of Orthodontic Treatment Need (DHC). Finish PAR was unaffected by Starting PAR. All other appliances: the model explained 25% of the variance for Finish PAR, which varied with Starting PAR and DHC scores. Social class had effects of little clinical significance, but the data suggested availability of orthodontic treatment was poorer in 'manual class' areas. Orthodontic qualifications, number of arches treated and mixed dentition starts had no significant effects when submitted to multivariate analysis.

CONCLUSIONS

The importance of appliance selection is reinforced: dual arch fixed appliances are generally more consistent. Lower social class areas may be poorly provided with orthodontic services.

A critical assessment of high-earning orthodontists in the General Dental Services of England and Wales (1990-1991)

Cases from the Dental Practice Board's 2 per cent random sample of completed cases which had been treated by orthodontic practitioners with high gross earnings, were compared to all the cases within the sample from other practitioners. They were assessed using the PAR index and IOTN. High earning orthodontists treated slightly more cases with lower objective need for treatment, but treated no more cases 'Unnecessarily' than other practitioners. They used more fixed appliances, and had marginally better levels of residual need for treatment at finish, although this was at least partially explained by lower levels at start. Generally, their standards were not substantially different to other practitioners. Appliance type had a marked effect on outcome, as did levels of malocclusion and need for treatment at start. Both groups of practitioners performed similarly (better) with dual arch fixed appliances: however, overall standards could only be described as mediocre. There is no justification to single out high earning orthodontists for special scrutiny. However, it may be beneficial if the system of remuneration in the General Dental Services could be modified to give more positive incentive to quality, rather than simply quantity of treatments.

The Barry Project--a cephalometric assessment of treatment change in a consecutive sample of malocclusion

This is the last of a three-part series examining the results of orthodontic treatment in a consecutive sample of malocclusion from a Welsh town. The cephalometric changes are compared for the different treatment regimes which were employed. Where the variables being examined were common to both radiographs and study cast records the treatment changes observed for the regimes were similar. Only limited 'skeletal' change, interpreted as a change in a few cephalometric measurements, was found to occur during treatment. Perhaps of most interest was the consistent reduction of 'A' point in the full fixed appliance group.

A comparison of orthodontic treatment changes as measured from study casts and cephalometric radiographs

Orthodontic treatment change was examined for 106 consecutively referred patients using serial lateral cephalometric radiographs and study cast records. The 2-D and 3-D measurement systems used to assess the changes were compared for five variables common to both sets of records. No statistical differences were found between the study cast and radiographic records for these variables. The 3-D measurement with the Reflex Metrograph showed marginally better precision in the measurement of the treatment changes examined. However, the main advantage was that it allowed a more thorough and accurate assessment of both individual incisor position and measurement error.

The Barry Project--a further assessment of occlusal treatment change in a consecutive sample: crowding and arch dimensions

In a further study of serially treated cases from a Welsh town, the results achieved for crowding, tooth alignment, residual spacing, tooth rotation, arch dimension, and centre line discrepancy are examined. The initial stability of the treatment change in these variables is also presented.