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.

Multiple-copy genes: production and modification of monomeric peptides from large multimeric fusion proteins.

A vector system has been designed for obtaining high yields of polypeptides synthesized in Escherichia coli. Multiple copies of a synthetic gene encoding the neuropeptide substance P (SP) (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2) have been linked and fused to the lacZ gene. Each copy of the SP gene was flanked by codons for methionine to create sites for cleavage by cyanogen bromide (CNBr). The isolated multimeric SP fusion protein was converted to monomers of SP analog, each containing a carboxyl-terminal homoserine lactone (Hse-lactone) residue (Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Hse-lactone), upon treatment with CNBr in formic acid. The Hse-lactone moiety was subjected to chemical modifications to produce an SP Hse amide. This method permits synthesis of peptide amide analogs and other peptide derivatives by combining recombinant DNA techniques and chemical methods.

Reduced binocular beat visual evoked responses and stereoacuity in patients with Duane syndrome.

PURPOSE: To study the effects that the abnormal eye movements of patients with Duane retraction syndrome have on the development of binocular function. METHODS: Pattern reversal visual evoked responses (VEPs) to 15-minutes-of-arc and 60-minutes-of-arc checks and binocular beat VEPs to diffuse sinusoidally modulated 18- and 20-Hz stimuli were recorded in 10 patients with Duane retraction syndrome who maintain binocular function by using an abnormal head posture. Visual acuity, stereoacuity, and eye movements were measured. The results have been compared to those from 10 normal subjects. RESULTS: The patients with Duane retraction syndrome had reduced stereoacuity compared to the normal control group (TNO mean, 82.5 seconds of arc compared to 37.5 seconds of arc; Titmus mean, 143 seconds of arc compared to 44 seconds of arc). The binocular beat VEPs showed a significantly reduced difference beat response at 2 Hz in the patients with Duane syndrome compared to normal subjects (mean signal-to-noise ratio 2.40 +/- 1.05 compared to 4.30 +/- 2.66; t = 2.21, df = 18, P < 0.05). Binocular enhancement of the P100 pattern reversal amplitude to 15-minute checks was increased in these patients, because of a reduction of the monocular P100 amplitudes compared to the normal group. CONCLUSIONS: Patients with Duane syndrome who maintain binocular function using an abnormal head posture have reduced stereoacuity and show electrophysiological evidence of reduced cortical binocular interaction.

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.

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.

A randomized clinical trial comparing 'one-step' and 'two-step' orthodontic bonding systems.

OBJECTIVE: The primary objective of this prospective clinical trial was to assess the clinical bond failure rates of orthodontic brackets bonded using a self-etching primer (SEP), compared with brackets bonded using a conventional acid-etched technique with control adhesive (Transbond). A secondary aim was to investigate whether characteristics of the operator, patient or tooth bonded had any influence on bracket failure. DESIGN: Single-centre randomized controlled clinical trial. Thirty-four patients were bonded, each being randomly assigned to either the test or control adhesive. SETTING: NHS Hospital Orthodontic Department, Chester, UK. SUBJECTS: Orthodontic patients requiring fixed appliance treatment. MAIN OUTCOME MEASURES: Bond failure. MAIN OUTCOME RESULTS: Failure rates over the initial 6-month period were 2.0% (Transbond) and 1.7% (SEP) with no statistically significant difference between the two groups. Over the duration of the fixed appliance treatment, bond failure rates increased, but remained acceptable at 7.4 % (TB) and 7.0% (SEP), respectively. When operator, patient and tooth characteristics were analysed, only the bracket location was found to be significant. Maxillary brackets were more likely to fail than mandibular brackets (RR 0.47%; 95% CI 0.22, 1.03). The failure rate for brackets in our study was low when compared with previous studies. CONCLUSIONS: Both the acid-etched control and self-etching primer in combination with adhesive pre-coated brackets were successful for clinical bonding. Their combined failure rate was lower than that reported in similar trials.

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.

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.

Perivascular smooth muscle alpha-actin is reduced in the endometrium of women with progestin-only contraceptive breakthrough bleeding.

It has been shown that the endometrium of women using progestin-only contraceptives has increased vascular fragility, although the structural basis for this weakness is unknown, as is its role in breakthrough bleeding (BTB). Perivascular cells such as pericytes and vascular smooth muscle cells surround capillaries during the maturation process following angiogenesis, and act to strengthen and stabilize the vessels. The aim of the present study was to quantify endometrial perivascular smooth muscle alpha-actin (alphaSMA) expression in women using Norplant with and without BTB problems, and compare it to controls. Using immunohistochemical techniques, vessels were classified as level 0, 1 or 2 depending on whether perivascular alphaSMA was absent, discontinuous or continuous. In 15 controls the subepithelial plexus had significantly more level 0 vessels than either the functionalis or basalis (61 +/- 4 versus 31 +/- 6 and 37 +/- 4%, P = 0.0006 and P = 0.0007 respectively). In contrast the functionalis and basalis had significantly more level 2 vessels than the subepithelial plexus (20 +/- 3 and 23 +/- 2 compared to 4 +/- 1%, P = 0.0005 and P = 0.000 respectively). The major finding of the study was that in Norplant users, where the relatively atrophic endometrium cannot be divided into different regions, women with BTB problems (n = 20) had significantly more level 0 vessels than those with reduced bleeding (n = 17) (60 +/- 4 versus 46 +/- 4%, P = 0.0302). Norplant users with BTB problems also had a non-significant reduction in level 2 vessels compared to women without bleeding problems (4 +/- 2 versus 11 +/- 4%, P = 0.0667). These results demonstrate that perivascular alphaSMA is reduced around the endometrial vessels of Norplant users with BTB compared to those with no bleeding problems, and strongly support the concept that reduced vascular structural integrity plays a key role in endometrial BTB.

Bcl-2, Fas and caspase 3 expression in endometrium from levonorgestrel implant users with and without breakthrough bleeding.

Women using the progestin-only contraceptive Norplant often suffer from unpredictable bouts of breakthrough bleeding, which usually occurs from a thin atrophic endometrium. The role of cellular apoptosis in the endometrial response to Norplant has not been investigated. The aim of the present study was to use immunohistochemistry to produce semi-quantitative scores for expression of the apoptosis-related proteins Bcl-2, Fas and caspase 3 in endometrium from 16 controls and 42 women using Norplant with minimal or major breakthrough bleeding problems. The results showed no difference in endometrial immunostaining for any of the three proteins between Norplant users with and without breakthrough bleeding. There was also no evidence of endometrial endothelial cell immunostaining for any of the proteins. Bcl-2 was the only protein to show a cyclical pattern, with higher expression in the proliferative compared to secretory glands. All three proteins showed different expression levels in control functionalis versus basalis, with the survival protein Bcl-2 being higher in basalis, and the death receptor Fas and the proteolytic enzyme caspase 3 being higher in the functionalis. Overall, the results suggest that apoptosis is regulated differently in functionalis compared to basalis, and that atrophic Norplant-exposed endometrium appears more like functionalis than basalis with respect to expression of Fas and caspase 3. There was no evidence for a role for apoptosis in the mechanisms that underlie progestin-induced endometrial breakthrough bleeding.

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.

Effects of hyperthermia on bone. I. Heating rate patterns induced by microwave irradiation in bone and muscle phantoms.

We describe the initial heating rate patterns generated by microwave irradiation of 915 MHz, with constant power output, in muscle-equivalent phantoms containing a freshly excised bone, and compared with those in phantoms consisting of muscle-equivalent gel only. At 1 cm depth the muscle was cooler in the centre of the field when bone was present underneath. Also, the orientation of the bone in the field had a pronounced effect on the heating rate profiles in the overlying muscle: when the long axis of the bone was parallel to E field, a hot area in the centre of the field was observed; after rotation of the applicator by 90 degrees so that the long axis of the bone was perpendicular to the E field, more homogeneous heating was obtained along most of the field. In contrast, the heating patterns obtained in the cortex of the bone at similar depth (1.3 cm) were not substantially influenced by its orientation in the field. Depending on field location, the heating rate of the cortical bone closest to the applicator was within 50-75% of the SAR in muscle at the same depth. We believe that these data may be useful for the extension of such measurements in vivo, to permit the effective application of hyperthermia, with or without radiation, in the treatment of bone lesions.