Journal of Orthodontics

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.

A new cyanoacrylate adhesive developed for orthodontic use was subjected to a controlled in vitro trial of ultimate shear bond strength. Performance deteriorated on storage in saline, rendering the material unsuitable for clinical use. Other alternatives to conventional acid-etch retained composite resin bonding agents are discussed.

An evaluation has been made of four techniques of assessing, from radiographs, the position of unerupted maxillary teeth, using radio-opaque markers placed in various positions on the maxilla of a dried skull. Application of the parallax principle in a vertical plane, for which only two radiographs are needed, was found to produce as many correct conclusions as other methods.

Study casts of the teeth are routinely used for diagnosis and to assess treatment change: the crowding of the teeth or shortage of space available within the dental arch is usually assessed visually. A full cast analysis program has been developed previously, making use of the three-dimensional Reflex Plotter linked to a computer. This study examines the validity of the fit of computer generated parabolic curves to dental arches, as performed in the measurement of crowding. Using a visual analogue method it was found that the parabola appeared to fit lower post-treatment dental arches best. However, reservations regarding the fit of symmetrical curves are expressed and other solutions suggested.

In those cases judged to be suitable for treatment by extractions in both arches and the use of upper removable appliances alone, the closure of excess residual space relies on mesial drift of the buccal segments. If opposing residual spaces are unequal in extent, there is a risk that space closure will be incomplete. Two cases are presented where a removable appliance was used to move a buccal segment mesially using a traction screw, and thereby close the excess residual space.

A 9-year-old boy suffering from cleidocranial dysplasia presented with multiple unerupted permanent teeth and five unerupted supernumerary teeth. During a 4-year observation and treatment period he developed nine more supernumerary teeth at a time when normally new teeth would no longer be forming. By the age of 13 years and 5 months a total of fourteen supernumerary teeth had been produced and it is possible that more teeth may develop in the future.

The relationship between social class and uptake of orthodontic treatment was investigated in a longitudinal cohort study of 1018 children living in South Glamorgan, Wales. Previous studies have shown that working class people make less use of dental services and receive inferior dental care than middle class people. The present investigation examined the role of one factor which appears likely to contribute to this effect: namely, the uptake of orthodontic treatment by families from different social classes. If a significant association were shown then findings relating to the effectiveness of orthodontic treatment might be confounded by this social class factor.

The tooth positioner is a one-piece, resilient appliance which may be used for finishing orthodontic cases. The appliance fills the free-way space, and covers the clinical crowns of all the teeth and about 3-mm of the buccal and lingual gingival mucosa. The positioner is constructed over a predetermined ‘setup’ and fabricated from either rubber or plastic. This article reviews the literature and describes the author's method of manufacture and usage.