Re-shaping NHS orthodontic provision - the North Wales experience.

The orthodontic service provision within North Wales, in common with many areas of the United Kingdom, was experiencing increasing waiting times for assessment and treatment. Reasons for this included an increasing population, patient demand and fixed NHS contracted orthodontic provision. In addition to these universal challenges, the geography of North Wales contributed to difficulties in accessing care. It was felt that with a reshaping of the orthodontic services there was potential to enhance the quality of orthodontic care available to patients and deliver prudent NHS orthodontic services. Three distinct, but inter-related steps, were identified to progress the reshaping of the service with the intended outcome of achieving an improved co-ordinated service. Initially, this involved the re-commissioning of the primary care specialist service through a formal retendering process. Following this, a standardised orthodontic referral form was developed, to be used for all orthodontic referrals regardless of whether their destination was a primary or secondary care provider. Finally, a formal accreditation process for all non-specialist dentists who were undertaking NHS orthodontic treatment was developed and implemented. The successful outcome of this process was only possible because of the close working partnership between the North Wales Orthodontic Managed Clinical Network (OMCN) and Betsi Cadwaladr University Health Board.

Orthodontic movement of two root fractured teeth: a case report.

AIM: To illustrate significant tipping orthodontic movement of root fractured teeth. SUMMARY: As the frequency of root fractured maxillary teeth is related to increased overjet and reduced lip coverage, orthodontic treatment may increase lip coverage and reduce the risk of trauma or its severity. It may also be necessary to move previously traumatized teeth. Two root fractured teeth were tipped through a considerable angle (19 degrees ) to reduce a large overjet and followed up for 5 years. KEY LEARNING POINTS: -- Reduction of large overjets involving root fractured teeth may not affect pulp vitality. -- Root fragment separation prior to orthodontics did not appear to increase in this patient, but angulation of the fragments did not completely follow the major change to the coronal part of the tooth.

A study of transposed canines in a sample of orthodontic patients.

Tooth transposition is a positional interchange of two adjacent teeth. The most commonly transposed tooth is the permanent canine with either the first premolar or lateral incisor. The records of 54 subjects with transposed canines, both maxillary and mandibular, were collected. Pretreatment study models of these subjects were matched with a similar number of models from unaffected individuals. Bucco-lingual and mesio-distal tooth widths, arch depth and arch width were measured on each model. Thirty-four subjects (63 per cent) were female. Thirty-seven (68.5 per cent) of the cases involved the maxillary arch and thirty-three (89.2 per cent) of these upper arch transpositions were of the canine and first premolar. In cases involving the lower arch the canine was invariably transposed with the lateral incisor. Peg-shaped lateral incisors, supernumerary and/or congenitally absent teeth occurred in 19 subjects. There were some small, but significant differences in the dimensions of some teeth, however there were no statistically significant differences in arch depths, arch widths and most tooth dimensions in subjects with and without transposed canines. These factors do not appear to be related to the development of canine transposition.

The provision of orthodontic treatment: some ethical considerations.

The majority of orthodontic procedures are elective, aimed at reorganising structures placed by nature in an area of stability. Although these structures are expressions of normal biological diversity, the costs and long-term benefits of treatment are generally accepted by society. In light of this, it is vital to provide orthodontic treatment that is done to the highest possible standard, using techniques based on a sound scientific basis, recognising that the main reason for the treatment is to improve a patient's self-esteem. This is valid reason for treatment, which can benefit a patient enormously. On this basis the patient can make an informed, autonomous decision on whether or not to undergo this treatment, knowing that the treatment benefits will outweigh the risks of having the treatment performed. Only then can the provision of orthodontic treatment be ethically justified.

The effects of disposable and custom-made impression trays on the accuracy of impressions.

This study indicates that some non-rigid impression trays, including disposable plastic trays and custom-made acrylic resin trays, may produce unreliable results when used with some medium-bodied elastomers. The study does not question the well-documented clinical accuracy of these elastomers when they are used with rigid trays. Disposable plastic trays are found to be acceptable when used with a combination of reversible and non-reversible hydrocolloid impression materials.

Persistence and convergence of ecosystems: an analysis of some second order difference equations.

Three second order difference equation models are analyzed and numerical solutions computed. It is shown that two concepts of ecosystem stability, the local property of convergence and the global property of persistence, do not coincide, and that the exislity are obtained and shown as parameter space diagrams. Examples of solution trajectories representative of different regions of this space are computed and discussed. A wide range of oscillatory behavior, as noted in recent papers by several authors, results. In addition, the erratic nature of regions of convergence to stable solutions is discussed.