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Biomedical subjects

S M Chadwick

Publications and source records attributed to S M Chadwick.

17 recordsLinked to original sources
PubMed2006

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.

Acid Etching, Dental↗
PubMed2005

Building a learning community on-line: the first step towards a national virtual learning environment in orthodontics.

Virtual learning environments (VLEs) are attractive solutions for the delivery of education on-line. Orthodontic education online has the potential to alleviate some of the problems caused by increasing demands on academic staff, the impact of the European work time directives and changes in junior doctors' hours. All act to constrain the effective training of orthodontic postgraduates. The design of a VLE is driven by modern concepts in learning and teaching, the structure, content and assessment methods will help determine the range of behaviours any programme hopes to encourage. This paper aims to provide information on how a modular specialist-training programme in the United Kingdom has been developed and enhanced by a VLE.

Computer-Assisted Instruction↗
PubMed2004

Current products and practices: curriculum development in orthodontic specialist registrar training: can orthodontics achieve constructive alignment?

This paper aims to encourage a debate on the learning outcomes that have been developed for orthodontic specialist education. In outcome-based education the learning outcomes are clearly defined. They determine curriculum content and its organization, the teaching and learning approaches, the assessment techniques and hope to focus the minds of the students on ensuring all the learning outcomes are met. In Orthodontic Specialist Registrar training, whether constructive alignment can be achieved depends on the relationship between these aspects of the education process and the various bodies responsible for their delivery in the UK.

Clinical Competence↗
PubMed2002

Teaching and learning: an update for the orthodontist.

Developments in teaching and learning have implications for every orthodontist. This paper describes some of the theories of teaching and learning that have led to a quiet revolution in higher education. Developments have included the incorporation of self-directed and problem-based learning concepts, together with a more active and interactive role for the learner. The importance of these changes for orthodontic education is discussed.

Feedback↗
PubMed2001

Functional regulator treatment of Class II division 1 malocclusions.

This controlled retrospective study aimed to identify the contribution of skeletal and dental changes in the correction of Class II division 1 malocclusions using Fränkel's functional regulator II (FRII), with reference to a concurrently recruited control group. One hundred and thirty-eight patients with Class II division 1 malocclusions were identified, those accepting treatment forming the study group and those declining treatment the control group. The study group (n = 70) were treated with a Fränkel appliance. Pre- and post-treatment observation cephalometric radiographs were analysed and compared. Mean values for both skeletal and dental variables in the control group were remarkably consistent throughout the study period; however, this masked individual variations in this group. The skeletal variables in the study group that showed statistically significant differences from the control group were SNB, ANB, BaNA and ANS-Me, but none of these was sufficiently large to be regarded as clinically significant. Dental variables showed clinically and statistically significant differences, including a 10 degree reduction in UI-Max and 3.1 degree increase in LI-Mand. The Fränkel appliance was thus found to be effective in producing desirable occlusal and dental changes in the majority of patients treated.

Adolescent↗
PubMed2001

Mandibular advancement using an intra-oral osteogenic distraction technique: a report of three clinical cases.

Osteogenic distraction has been used for decades to lengthen limbs and now attention is focused upon its use within the craniofacial skeleton. This paper addresses distraction of the mandible. It is proposed that mandibular osteogenic distraction could be a possible adjunct to the orthodontic treatment of those adult patients with skeletal anomalies, who would benefit from combined orthodontic/orthognathic treatment. Three consecutive cases from one unit are presented, where adult patients with severe Class II division 1 malocclusions have undergone orthodontic treatment combined with mandibular osteogenic distraction, instead of conventional bilateral sagittal split osteotomies.

Adolescent↗
PubMed2001

Fluoride-releasing elastomeric modules reduce decalcification: a randomized controlled trial.

OBJECTIVE: To determine whether fluoride releasing elastomeric modules reduced the incidence of decalcification around orthodontic brackets during a complete course of orthodontic treatment. DESIGN: A randomised controlled, split mouth design. SETTING: The study was carried out in the orthodontic department of Newcastle-upon-Tyne Dental Hospital, UK. SUBJECT AND METHODS: 21 consecutive patients (126 teeth) undergoing fixed appliance therapy were studied. A split mouth technique was adopted to examine the upper labial segment, where one side (left or right) was randomly assigned to the experimental group, and the opposite side served as a control throughout their course of orthodontic treatment. INTERVENTIONS: The control teeth were ligated to the archwire using conventional modules. The experimental teeth were ligated to the archwire using Fluoride releasing elastomeric modules. OUTCOME MEASURES: Standardised photographs were taken of the upper labial segment before and after completion of orthodontic treatment, and the degree of decalcification assessed in each tooth quadrant, using a modification of the Enamel Defect Score. RESULTS: Decalcification was found to occur in both treatment groups, though to a significantly greater degree on the control side (p = 0.002). The fluoride module side showed significantly fewer serious decalcified lesions than the control (p = 0.013). No patients withdrew from the study. CONCLUSIONS: It would appear that the use of fluoride releasing elastomeric modules reduces the degree of decalcification experienced during orthodontic treatment.

Fluorides↗
PubMed2000

Fluoride-releasing elastomerics--a prospective controlled clinical trial.

A prospective controlled clinical trial was undertaken to evaluate the effectiveness of stannous fluoride-releasing elastomeric modules (Fluor-I-Ties) and chain (Fluor-I-Chain) in the prevention of enamel decalcification during fixed appliance therapy. Forty-nine patients (782 teeth) were included in the experimental group, where the fluoride-releasing elastomerics were used. Forty-five patients (740 teeth) who received non fluoride-releasing elastomerics formed the control group. All patients had their elastomerics replaced at each visit. Enamel decalcification incidence and distribution were recorded using an index by direct clinical observation. In the control group enamel decalcification occurred in 73 per cent of patients and in 26 per cent of all teeth. In the experimental group the corresponding incidence was 63 and 16 per cent, respectively. The overall reduction in score per tooth produced by the fluoride-releasing elastomerics was 49 per cent, a highly significant difference (P < 0.001). A significant difference was seen in all but the occlusal enamel zones. The majority (over 50 per cent) of lesions occurred gingivally. The teeth most severely affected were the maxillary lateral incisors and mandibular second premolars. There was no difference in treatment duration between groups.

Adolescent↗
PubMed1999

A modification to enable controlled progressive advancement of the Twin Block appliance.

A modification of the Twin block appliance has been developed to facilitate controlled gradual advancement of the mandibular position during the treatment of Class II division I malocclusions. This features the incorporation of stainless steel screws with conical heads into the blocks of the upper appliance to provide the inclined plane effect. Advancement is by the addition of polyacetal spacers between the screw heads and the upper blocks. The system is designed to improve the clinical flexibility of the appliance and to enhance patient acceptance in cases where mandibular protrusion is limited initially. Another possible application is gradual reactivation for Class III correction. Other advantages are reduced laboratory and clinical time during reactivation of the appliance, and perhaps a more physiological response to the growth modification process. The design and construction of the advancement system is illustrated, and its clinical use discussed.

Humans↗
PubMed1998

The use of myofunctional appliances in the UK: a survey of British orthodontists.

A questionnaire was sent out to members of the British Orthodontic Society in an attempt to establish how myofunctional appliances are currently used in the UK and to attempt to explain the differences between provider groups. This article reports the findings of this survey and that, of all the appliances currently available, British orthodontists prefer to use the Twin Block appliance. Furthermore, most of the sample questioned felt that the laboratory cost of many myofunctional appliances meant their provision under the General Dental Service was not practical.

Analysis of Variance↗
PubMed1997

The orthodontic management of patients with profound learning disability.

The orthodontic management of patients with profound learning disability is described including a report of two cases. Close co-operation between the orthodontist and other providers of dental treatment is essential for the management of this group of patients, and a general anaesthetic may be needed to allow fixed appliances to be placed. The orthodontic treatment is co-ordinated with any necessary restorative or periodontal treatment. The moral and ethical questions raised by the treatment offered to this group of patients are discussed.

Anesthesia, Dental↗
PubMed1996

Problems of root resorption in relation to orthodontic treatment planning: a report of three cases.

Three cases are described illustrating problems of root resorption related to orthodontic treatment. In the first case the short roots of many of the teeth made it inappropriate to carry out orthodontic treatment. In the second case there were no signs of root resorption initially, but, following retraction of maxillary incisors with a removable appliance, root resorption was noted affecting molar and premolar teeth, but not the maxillary incisors. In the third case several teeth had short roots, and further shortening of roots occurred during fixed appliance therapy. These cases illustrate the unpredictable nature of root resorption.

Adolescent↗
PubMed1995

An investigation into the fluoride release of a variety of orthodontic bonding agents.

The purpose of this study was to compare the fluoride release from a variety of orthodontic bonding agents. Fluoride release into de-ionized water was measured over a 20-week period. Material based on the fluoride exchange resin was also tested in a saline solution. Fluoride release from a variety of orthodontic bonding agents was compared and the amount of release found to be highly variable. Glass ionomer-based materials showed substantially greater fluoride release when compared with resin-based materials. The presence of anions (Cl-) did not improve the release from fluoride exchange resin. Glass ionomer/resin hybrid material (Vitrabond) released the greatest amount of fluoride.

Adhesives↗
PubMed1995

An investigation to estimate the fluoride uptake adjacent to a fluoride-releasing bonding agent.

Decalcification of the teeth remains a problem during orthodontic treatment with fixed appliances. It has been suggested that bonding agents which release fluoride could supply it to the area of the tooth most at risk from decalcification. The aim of this study was to estimate uptake by enamel adjacent to a fluoride releasing bonding agent. Acid etch biopsies were used to estimate the concentration of fluoride in enamel adjacent to brackets bonded with Vitrabond and Geristore. Results indicate that there was a significant increase in the concentration of fluoride in enamel adjacent to Vitrabond. The clinical significance of the increase in the concentration of fluoride adjacent to Vitrabond and the mechanism by which fluoride moves from the material into the enamel remain unclear.

Acid Etching, Dental↗
PubMed1995

Dilaceration of a permanent mandibular incisor. A case report.

A case is described where a permanent mandibular incisor was found to be dilacerated. Histological examination of the extracted tooth was consistent with trauma, although there was no supporting history. These findings are discussed and the orthodontic implications are considered.

Child↗
PubMed1993

Late development of supernumerary teeth: a report of two cases.

Two cases are presented of late developing supernumerary teeth. In the first the patient developed two crops of supernumeraries, both of which were found on radiographic examination following delay in the normal eruption pattern of the permanent dentition. The first crop of four supernumerary teeth were in the maxillary incisor region and were surgically removed; 5 years later four more supernumerary teeth was found in the maxillary canine and mandibular premolar regions, which were also surgically extracted. In the second case two supplemental mandibular premolars were found as an incidental finding on radiographic examination at the age of 15 years following orthodontic treatment, the patient having previously had four first premolars extracted; these supernumerary teeth were not extracted as they were asymptomatic. These cases emphasize the importance of careful review of patients with a history of supernumerary teeth and, where clinically indicated, of further radiographic examination.

Adolescent↗