The development of the index of complexity, outcome and need (ICON).
(1/90)
This paper is based on the winning submission for the 1998 Chapman prize awarded by the British Orthodontic Society for an essay on a subject promoting the interests of orthodontics. The aim of the investigation is to develop a single index for assessing treatment inputs and outcomes. An international panel of 97 orthodontists gave subjective judgements on the need for treatment, treatment complexity, treatment improvement, and acceptability on a diverse sample of 240 initial and 98 treated study models. The occlusal traits in the study models were scored according to a defined numerical protocol. Five highly predictive occlusal traits were identified (IOTN Aesthetic Component, crossbite, upper arch crowding/ spacing, buccal segment antero-posterior relationships, and anterior vertical relationship) and then used to 'predict' the panelist's decisions using regression analysis. Cut-off values were determined for the dichotomous judgements by plotting specificity sensitivity and overall accuracy. Twenty percentile ranges were used to determine 5 grades of complexity and improvement. The index prediction of decisions for treatment need, had specificity 84.4 per cent, sensitivity 85.2 per cent, and overall accuracy 85 per cent. When used to predict treatment outcomes, the new index had specificity 64.8 per cent, sensitivity 70.1 per cent, and overall accuracy 68.1 per cent. The index could explain 75.6 per cent of the variance in the mean casewise complexity score and 63.5 per cent of the mean casewise improvement score. A new orthodontic index is proposed to assess treatment need, complexity, and outcome. It is based on international orthodontic opinion. (+info)
A validation of two orthognathic model surgery techniques.
(2/90)
In order to create an evidence-based orthognathic surgery planning protocol, an investigation of two popular model surgery techniques, the Lockwood keyspacer and the Eastman anatomically-orientated system was carried. This determined (a) the accuracy of positioning of the maxillary cast according to the prescribed treatment plan and (b) the relocation of the maxilla after a simulated Le Fort I down fracture osteotomy using the intermediate wafer as a guide. Fifteen patients-five Class II division 1, five Class II division 2, and five Class III-were included in the study. All the measurements were taken with Erickson's vertically mounted electronic caliper and variations from the treatment plan were analysed. The mean model surgery positioning errors +/- SD (mm) were: (i) vertical plane-Lockwood -0*8 +/- 1*6 and Eastman 0*00 +/- 1*0 (P = 0*0001); (ii) anteroposterior plane-Lockwood 1*2 +/- 1*8 and Eastman -0*1 +/- 1*4 (P = 0*05); and (iii) transverse plane-Lockwood 0*9 +/- 0*9 and Eastman 1*0 +/- 0*9 (P = 0*34). After the simulated osteotomy, the mean errors +/- SD were: (i) vertical plane-Lockwood -0*5 +/- 1*5 and Eastman 0*3 +/- 1*1 (P = 0*001); (ii) in anteroposterior plane-Lockwood 0*8 +/- 2*0 and Eastman 0*7 +/- 1*0 (P = 0*89); and (iii) transverse plane-Lockwood 0*8 +/- 0*6 and Eastman 0*7 +/- 0*5 (P = 0*83). The Eastman technique was relatively better especially in the vertical plane. The variations from the treatment plan were on the whole anatomically small, but in some cases could be clinically significant. (+info)
Functional occlusion: II. The role of articulators in orthodontics.
(3/90)
Opinion is divided on whether there is a place for the use of semi-adjustable dental articulators in orthodontics. In this review we explore the validity and reproducibility of the techniques involved in mounting study models on a semi-adjustable dental articulator. We also look at the role of articulated study models in orthodontic diagnosis and treatment planning, in the finishing stages of orthodontics and in planning for orthognathic surgery. We report that each of the many stages involved in mounting study models on a semi-adjustable articulator is a potential source of error and that only if the technique is carried out with a high degree of accuracy is it worth the additional chairside time. (+info)
Craniofacial morphology of Japanese girls with Class II division 1 malocclusion.
(4/90)
OBJECTIVE: To identify the craniofacial features of Japanese girls with Class II division 1 malocclusions. METHOD: One hundred and ninety lateral cephalometric radiographs were analysed, and the subjects whose age ranged from 7 years 6 months to 15 years 10 months were divided into three groups by their dentition: middle mixed dentition, late mixed dentition, and early permanent dentition. The mean values of 5 linear and 16 angular cephalometric parameters were compared with established Japanese Class I control values. RESULTS: Japanese girls with Class II division 1 malocclusion had a significantly small S-N-B angle (p < 0.001), short mandibular ramus (p < 0.05-0.001), and a large mandibular plane angle (p < 0.05-0.001). CONCLUSION: Japanese girls with Class II division 1 malocclusion had a high-angle facial pattern associated with the short mandibular ramus. (+info)
The examination and recording of the occlusion: why and how.
(5/90)
Before presenting 'how' the examination and recording of the occlusion may be achieved, some attempt should be made to justify 'why' it is necessary. It may appear to be a strange way of justifying the need to examine the patient's occlusion, but this will initially involve a study of the influences of mandibular movements. (+info)
Good occlusal practice in simple restorative dentistry.
(6/90)
Many theories and philosophies of occlusion have been developed. 1-12 The difficulty in scientifically validating the various approaches to providing an occlusion is that an 'occlusion' can only be judged against the reaction it may or may not produce in a tissue system (eg dental, alveolar, periodontal or articulatory). Because of this, the various theories and philosophies are essentially untested and so lack the scientific validity necessary to make them 'rules'. Often authors will present their own firmly held opinions as 'rules'. This does not mean that these approaches are to be ignored; they are, after all, the distillation of the clinical experience of many different operators over many years. But they are empirical. In developing these guidelines the authors have unashamedly drawn on this body of perceived wisdom, but we would also like to involve and challenge the reader by asking basic questions, and by applying a common sense approach to a subject that can be submerged under a sea of dictate and dogma. (+info)
Good occlusal practice in advanced restorative dentistry.
(7/90)
In most patients the existing occlusal scheme will be functional, comfortable and cosmetic; and so if a tooth or teeth need to be restored, the most appropriate way to provide the restoration(s) would be to adopt a 'conformative' approach: that is to provide treatment within the existing envelope of static and dynamic occlusal relationships. There will, however, be situations where the conformative approach cannot be adopted, and this section aims to describe what is 'Good Occlusal Practice' in these circumstances. (+info)
Good occlusal practice in removable prosthodontics.
(8/90)
The loss of teeth may result in patients experiencing problems of a functional, aesthetic and psychological nature. This section addresses the very important subject of occlusal considerations for partial and complete dentures. The occlusion is particularly important given the bearing that occlusal factors have, especially on edentulous patients. (+info)