An introduction to dento-legal issues and risks in orthodontics.

Orthodontic treatment is not without risk. This article aims to look at some of the dento-legal issues surrounding orthodontic treatment, the risks to both the clinician and the patient, and how some of these risks can be mitigated.

Factors which influence working patterns of orthodontists in the United Kingdom.

OBJECTIVE: To describe factors which influence the current working patterns of orthodontists in the United Kingdom. DESIGN AND SETTING: A cross-sectional postal questionnaire to orthodontic specialists in the United Kingdom. SUBJECTS: All those on the specialist list in orthodontics held by the General Dental Council in 2006-2007. MATERIALS AND METHODS: The data gathered included demographic details (gender, ethnicity, age, professional status and number of children), calendar year of achieving professional qualifications and current working patterns, together with details of any career breaks taken and geographical location of work. RESULTS: The response rate was 81.5%. Male and female orthodontists were seen to have different working patterns. The difference was statistically significant with male orthodontists undertaking clinical work on average 1.5 sessions more per week than their female colleagues. The calendar year of completion of undergraduate studies and the number of children an orthodontist has can significantly affect the number of clinical sessions they work each week. In recent years it has been observed that there is greater ethnic diversity among the workforce but ethnic origin appeared to have a minimal effect on the number of clinical sessions worked each week. The amount and length of career breaks taken by female orthodontists was greater than their male colleagues. In addition, there continues to be an uneven distribution of orthodontists throughout the United Kingdom. CONCLUSION: Many factors influence the current working patterns of orthodontists in the United Kingdom. However, it may be the inequitable regional distribution of orthodontists throughout the United Kingdom which is of greatest significance to orthodontic workforce planning for the future.

Changes in the gender and ethnic balance of the United Kingdom orthodontic workforce.

OBJECTIVE: To describe the gender and ethnic trends of the United Kingdom orthodontic workforce. DESIGN AND SETTING: A cross-sectional survey using a postal questionnaire to specialist orthodontic practitioners in the United Kingdom (2006-2007).Subjects All those on the Specialist List in Orthodontics held by the General Dental Council in October 2006. MATERIALS AND METHODS: The data collected using the questionnaire included demographic details (gender, ethnicity, current age, place of birth), undergraduate and postgraduate dental schools attended, calendar years in which professional qualifications were achieved, anticipated year of retirement and geographical location of work place. RESULTS: The response rate was 81.5%. There are more male (60.2%) than female (39.8%) orthodontists presently working in the United Kingdom. Minority ethnic groups are better represented amongst the orthodontic workforce than they are in the general population, however their distribution throughout the United Kingdom is uneven. The trends in the results indicate that the gender and ethnic balance of the specialist orthodontic workforce has been changing and the proportion of females and those from non-white ethnic groups has increased. In contrast, the majority of those retiring over the next few years will be white males (60%). CONCLUSION: This study suggests that there will be greater ethnic diversity and more female orthodontists in the future workforce. Consequently, working patterns should be kept under regular review so that an optimal orthodontic service can be maintained in the United Kingdom.

Indices of extracellular matrix turnover in human masseter muscles as markers of craniofacial form--a preliminary study.

Environmental remodelling of the craniofacial musculature is obligatory for successful outcomes following interventions such as functional appliance therapy or orthognathic surgery. Genetically driven remodelling of the craniofacial musculature is also seen in individuals with altered facial form. The processes that are involved in the remodelling of intramuscular connective tissue need to be activated in such situations. Such processes require activity of matrix metalloproteinases (MMPs) and the tissue inhibitors of matrix metalloproteinases (TIMPs), which are responsible for extracellular matrix (ECM) turnover. The aim of this study was, therefore, to establish the expression of MMP-2 and MMP-9 and their inhibitors, TIMP-1 and TIMP-2, in the masseter muscle of humans with both normal and increased vertical facial form and to assess whether this expression had any value as a predictor of facial form. Biopsies were taken from 20 subjects (10 with vertical facial deformity and 10 with normal vertical facial form to act as a control group). The sample group consisted of 15 females and 5 males and the average age of the donors +/- standard deviation (SD) was 26.04 +/- 6.16 years (range: 17.67-31.25 years). Biopsy samples were then subjected to zymography and reverse zymography to assess MMP and TIMP expression, respectively. Lateral skull cephalograms were analysed for each subject using Spearman's rho correlation coefficients and Mann-Whitney U-tests. TIMP-1 activity was consistently expressed in human masseter muscle. MMP-2, MMP-9, and TIMP-2 activity, when detected, was at a low level. These data indicate that in most individuals, an excess of TIMP-1, compared with MMP-2 and MMP-9, limits ECM turnover in human masseter muscle. There was a demonstrable variation in proteinase expression between different individuals. These preliminary findings, however, do not confirm that indices of ECM turnover are a reflection of an individual's vertical facial form.

Craniofacial muscle engineering using a 3-dimensional phosphate glass fibre construct.

The current technique to replace missing craniofacial skeletal muscle is the surgical transfer of local or free flaps. This is associated with donor site morbidity, possible tissue rejection and limited supply. The alternative is to engineer autologous skeletal muscle in vitro, which can then be re-implanted into the patient. A variety of biomaterials have been used to engineer skeletal muscle with limited success. This study investigated the use of phosphate-based glass fibres as a potential scaffold material for the in vitro engineering of craniofacial skeletal muscle. Human masseter (one of the muscles of mastication)--derived cell cultures were used to seed the glass fibres, which were arranged into various configurations. Growth factors and matrix components were to used to manipulate the in vitro environment. Outcome was determined with the aid of microscopy, time-lapse footage, immunofluorescence imaging and CyQUANT proliferation, creatine kinase and protein assays. A 3-dimensional mesh arrangement of the glass fibres was the best at encouraging cell attachment and proliferation. In addition, increasing the density of the seeded cells and using Matrigel and insulin-like growth factor I enhanced the formation of prototypic muscle fibres. In conclusion, phosphate-based glass fibres can support the in vitro engineering of human craniofacial muscle.

Traumatised permanent teeth in 11-16-year-old Saudi Arabian children with a sensory impairment attending special schools.

- The aim of this study was to determine the prevalence of traumatised permanent teeth among sensory (visual (VI) and hearing (HI)) impaired children attending special schools in Riyadh, Saudi Arabia. All the dental injuries involved incisor teeth, and trauma was noted in 33 (6.7%) children attending government schools (control group) compared to 7 (9%) VI children and 24 (11.4%) HI children. Differences in the dental trauma only reached statistical significance between the HI and control group (P < 0.05). Gender differences were only apparent in the HI group, with males having higher levels of traumatised teeth. In addition, HI children aged 11-12 years were more prone to trauma than children in the control group of the same age (P < 0.05). In conclusion, sensory impaired children do have a tendency for more dental trauma. However, this was only statistically significant for HI children. Whereas a gender difference was most noticeable for the HI group, with males having higher levels of trauma, this was noticeable by its absence among VI children.

Orthodontic treatment need and self-perception of 11-16-year-old Saudi Arabian children with a sensory impairment attending special schools.

AIM: To determine the self-perception and need for orthodontic treatment in young sensory [visual (VI) and hearing (HI)] impaired children attending special schools in Riyadh, Saudi Arabia. Also, to determine if gender and social class background influence the rating and self-perception of malocclusion among the children. LOCATION: Riyadh, Saudi Arabia. DESIGN: A prospective study on orthodontic treatment need in sensory impaired children. SUBJECTS: Seventy-seven VI, 210 HI, and 494 control (C) children aged 11-16 years. METHOD: The aesthetic component (AC) of the Index of Orthodontic Treatment Need (IOTN) was determined using the standard 10 pictures for the C group and HI with a modified version (tactile graphic) for VI. The dental health component (DHC) and AC of IOTN were used to allocate each child to no need, borderline need and definite need for treatment subgroups. RESULTS: Sixty-five per cent of VI, 21.8 per cent HI, and 18.7 per cent of the C were perceived to be in need of orthodontic treatment. However, 55.8 VI, 43 per cent HI and 34 per cent C were rated for treatment need based upon the AC. The difference between the examiner and the child's rating of treatment need was found to be statistically significant among the HI and control children (P < 0.001). CONCLUSION: The VI children who were scored for treatment by the examiner as having need for treatment had similar perceptions of their treatment need irrespective of their social background. Male VI children had a higher DHC score, but both VI and HI males had a higher normative and self-perceived need based on AC.

The extracellular matrix of muscle--implications for manipulation of the craniofacial musculature.

Successful adaptation of craniofacial skeletal muscle is dependent upon the connective tissue component of the muscle. This is exemplified by procedures such as distraction histo/osteogenesis. The mechanisms underlying remodelling of intramuscular connective tissue are complex and multifactorial and involve extracellular matrix (ECM) molecules, receptors for the ECM (integrins) and enzymes that remodel the ECM (MMPs). This review discusses the current state of knowledge and clinical implications of connective tissue biology as applied to craniofacial skeletal muscle.

Attitudes of dentists, working in Riyadh, toward people with a sensory impairment.

This study was conducted to determine the attitudes of dentists, working in Riyadh, toward people with a sensory impairment (SI), according to the Scale of Attitude Towards Disabled Persons (SADP). The SADP scale was modified to focus solely upon sensory impairment. The modified scale was pre-tested and then incorporated into a self-administered questionnaire. This was then administered to 600 dentists (response rate, 73.7%) working in the city of Riyadh, Saudi Arabia. The modified scale showed itself to be reliable, with a Chronbach's coefficient alpha 0.616 and four-factor analysis, which accounted for 38.5% of the variance. Ninety-four percent of the dentists were generally positive toward SI in the society. There were, however, significant variations in attitudes, with a more positive score for dentists who had worked for 30 years or more (p < 0.005), were specialists (p < 0.005), received little or no undergraduate training in this subject (p < 0.05), and who received their undergraduate training in Europe/North America (p < 0.001). However, in a stepwise regression model, all these variables were significant except for the years of practice. The modified SADP showed dentists, working in Saudi Arabia, having a positive attitude toward people with SI.

Craniofacial morphology of Japanese girls with Class II division 1 malocclusion.

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.

Morphology of the temporomandibular joint in skeletal class iii symmetrical and asymmetrical cases: a study by cephalometric laminography.

The aetiology of asymmetric growth in the mandible is not well understood. Previous studies have indicated that the functional lateral shift of the mandible in the period of prepubertal growth may translate to a true skeletal asymmetry, exclusively in skeletal Class III malocclusion. This asymmetry develops more characteristic features during the pubertal and post-pubertal growth periods. Early correction of a functional lateral shift of the mandible is recommended. The purpose of this study was to examine the relationship between the morphology of the temporomandibular joints and asymmetry in skeletal Class III malocclusion in adult female patients. Cephalometric and laminographic findings in 36 asymmetric skeletal Class III patients with a lateral shift of mandible (group 3) were compared to those of 25 symmetric skeletal Class I patients (group 1) and the same number of symmetric skeletal Class III malocclusions (group 2). All the patients had received no orthodontic treatment. The results showed that the TMJ of the side to which the mandible shifted showed a significantly narrower and shorter shape of the condyle head, smaller superior condylar space, and steeper eminence than those of the unshifted side.

Quality of life and its importance in orthodontics.

Over the last 10-15 years, the terms quality of life (QOL) and health-related quality of life (HRQL) have been seen increasingly in medical literature. Much of the orthodontic treatment that is undertaken is justified on the basis of improving health-related quality of life. With this in mind, studying HRQL in orthodontic patients has the potential to provide information about treatment needs and outcomes, and may also facilitate improved care. Clinicians should therefore be aware of some of the ways in which health-related quality of life may be assessed. The first part of this review article looks at the general concepts of health-related quality of life, whilst the second section focuses on dentistry and orthodontics.

A comparison of information retention at an initial orthodontic consultation.

The exchange of information is an everyday part of orthodontic treatment. However, the amount of information that is understood and retained, by patients and their parents, is not known. There has been very little research in the area of information retention in dentistry. This has implications with the demands for improved provision of information for patients. This questionnaire-based study, compared the effectiveness of written, verbal, and visual methods of providing orthodontic information. It assessed the retention of this information, by patients and parents, in both the short- and long-term. Twenty-eight patients and their parents, were allocated alternately into one of three groups, receiving written, verbal, or visual information. Short-term retention of knowledge was assessed 10-15 minutes after receiving the information and long-term retention rated by a second questionnaire mailed 8 weeks later. Overall, little difference was found between the three methods. The findings suggested that verbal information should not be given to patients unless supplemented by written and/or visual information, and that parents were more attentive to verbal instructions than their children.

The effect of micro-etching on the retention of orthodontic molar bands: a clinical trial.

Failure of orthodontic bands occurs most frequently at the band-cement interface, when conventional glass ionomer cements are used. Modification of the band surface may improve clinical performance by increasing the mechanical interlock at this junction. The aim of this prospective study was to compare the retention of micro-etched and untreated first molar orthodontic bands in a randomized, half-mouth trial. Seventy-nine patients had 304 bands cemented as part of routine fixed appliance therapy. The effect of micro-etching, patient age and gender, operator, molar crossbite, treatment mechanics, and arch on band failure was investigated. Failure rates and survival times were compared for each variable assessed. Micro-etched molar bands showed a significant reduction in clinical failure rate over untreated molar bands and an increase in mean survival time (P < 0.001). Of the other variables examined, only the presence of a molar crossbite had any significant effect on band failure (P = 0.004).

Are pre-treatment psychological characteristics influenced by pre-surgical orthodontics?

A number of investigations have looked at psychological changes occurring in association with orthognathic treatment. However, most of these studies have used a pre-surgery questionnaire as the baseline measurement. There is little data relating to the true baseline, i.e. that prior to any active treatment. Until this aspect is investigated, it is not possible to assume that pre-surgery is an acceptable baseline. This questionnaire based study aimed to assess changes in six psychological outcome measures between T1 (prior to any active treatment) and T2 (following pre-surgical orthodontics/prior to surgery). The outcome variables were: state anxiety, trait anxiety, depression, self-esteem, body image, and facial body image. Sixty-two patients (39 females and 23 males) completed both questionnaires. The results showed that intervention, in the form of orthodontic treatment, had a minimal effect on the chosen psychometric outcome variables. There was a significant reduction in satisfaction with body image amongst patients who initially reported mild to moderate dental/facial problems, whilst a moderate increase in satisfaction occurred in those patients reporting severe conditions initially. Also of note were significant increases in state anxiety amongst older patients whilst trait anxiety showed greater increases in females than males.

A comparison of parents' and patients' views of orthognathic treatment.

The aim of this study was to assess parents' views of orthognathic treatment and compare them with the views of their son or daughter who underwent the treatment. Fifty patients who had undergone orthognathic treatment and one of their parents were recruited over an 8-month period between July 1999 and March 2000. The study was a retrospective, questionnaire-based study. Comparison of parents' and patients' views was undertaken using Cohen's kappa coefficient. This was also used to compare individual parent and patient views pre- and posttreatment. Response rates were 90% (n = 45) for patients and 80% (n = 40) for parents. Parents rated their son or daughter as having a more attractive facial and dental appearance and higher levels of self-confidence both pre- and posttreatment than the patients graded themselves. Parents and patients both felt there was significant improvement in facial and dental appearance and self-confidence following treatment.

Classifying vertical facial deformity using supervised and unsupervised learning.

OBJECTIVES: To evaluate the potential for machine learning techniques to identify objective criteria for classifying vertical facial deformity. METHODS: 19 parameters were determined from 131 lateral skull radiographs. Classifications were induced from raw data with simple visualisation, C5.0 and Kohonen feature maps; and using a Point Distribution Model (PDM) of shape templates comprising points taken from digitised radiographs. RESULTS: The induced decision trees enable a direct comparison of clinicians' idiosyncrasies in classification. Unsupervised algorithms induce models that are potentially more objective, but their blackbox nature makes them unsuitable for clinical application. The PDM methodology gives dramatic visualisations of two modes separating horizontal and vertical facial growth. Kohonen feature maps favour one clinician and PDM the other. Clinical response suggests that while Clinician 1 places greater weight on 5 of 6 parameters, Clinician 2 relies on more parameters that capture facial shape. CONCLUSIONS: While machine learning and statistical analyses classify subjects for vertical facial height, they have limited application in their present form. The supervised learning algorithm C5.0 is effective for generating rules for individual clinicians but its inherent bias invalidates its use for objective classification of facial form for research purposes. On the other hand, promising results from unsupervised strategies (especially the PDM) suggest a potential use for objective classification and further identification and analysis of ambiguous cases. At present, such methodologies may be unsuitable for clinical application because of the invisibility of their underlying processes. Further study is required with additional patient data and a wider group of clinicians.

Gelatinase-B (matrix metalloproteinase-9; MMP-9) secretion is involved in the migratory phase of human and murine muscle cell cultures.

The remodelling of connective tissue components is a fundamental requirement for a number of pivotal processes in cell biology. These may include myoblast migration and fusion during development and regeneration. In other systems, similar biological processes are facilitated by secretion of the matrix metalloproteinases (MMPs), especially the gelatinases. This study investigated the activity of the gelatinases MMP-2 and 9 by zymography on cell conditioned media in cultures of cells derived from explants of the human masseter muscle and in the murine myoblast cell-line C2C12. Expression of MMP-9 by western blotting and TIMP-1, the major inhibitor of MMPs, by northern blotting, during all phases of myoblast proliferation, migration, alignment and fusion, was also measured. Irrespective of the origin of the cultures, MMP-9 activity was secreted only by single cell and pre-fusion cultures whilst MMP-2 activity was secreted at all stages as well as by myotubes. The loss of MMP-9 activity was due to the loss of MMP-9 protein expression. TIMP-1 mRNA was not detectable at the single cell stage but its expression increased as cells progressed through the pre-fusion and post-fusion stages to reach a maximal in myotube containing cultures. Migration of cells derived from human masseter muscle was inhibited, using a specific anti-MMP-9 blocking monoclonal antibody (6-6B). These data are consistent with the concept that regulation of matrix turnover via MMP-9 may be involved in the events leading to myotube formation, including migration. Loss of expression of this enzyme and expression of TIMP-1 mRNA is associated with myotube containing cultures. Consequently, the ratio between MMPs and TIMPs maybe important in determining myoblast migration and differentiation.

A comparison of health state utilities for dentofacial deformity as derived from patients and members of the general public.

The cost-utility approach is a method of economic evaluation, which assigns a ratio of cost to benefit, based on utility values of the health state in question. It allows efficient use of health care resources and is a useful method in that it permits comparison of a wide range of medical interventions, including those which are life saving and those that improve quality of life. This study obtained utility values for dentofacial deformity from orthognathic patients and members of the general public using three recognized methods--rating scale (RS), standard gamble (SG), and time trade-off (TTO). There were no significant differences between the utility values for the two groups of respondents. Method agreement between the TTO and the SG (the 'gold standard') was better than that between the RS and SG. In addition, the SG and TTO were found to have greater repeatability than the RS.

Development of a condition-specific quality of life measure for patients with dentofacial deformity: I. Reliability of the instrument.

UNLABELLED: The assessment of quality of life is becoming increasingly important in clinical research. Its importance in dentistry has been realised only relatively recently. Health-related quality of life is concerned with the aspects of quality of life that relate specifically to an individual's health. This may be measured using two groups of instruments: (i) generic measures, which provide a summary of health-related quality of life and sometimes generate a single index measure of health or (ii) condition-specific measures, which focus on a particular condition, disease, population or problem and are potentially more responsive to small, but clinically important, changes in health. OBJECTIVES: The aim of this study was to develop a condition-specific quality of life measure for those patients with severe dentofacial deformity who were requesting orthognathic treatment and to assess the reliability of this instrument. METHOD: Instrument content was derived through a literature review and interviews with clinicians and patients. The resulting instrument was tested for internal consistency and test-retest reliability. RESULTS AND CONCLUSION: The instrument was found to divide into four clinically meaningful domains. Internal consistency and test-retest reliability were good. Patient acceptance of the questionnaire was also encouraging.