Biomedical subjects

N P Hunt

Publications and source records attributed to N P Hunt.

At least 19 recordsLinked to original sources

PubMed2003

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.

Adolescent↗

PubMed2003

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.

Adolescent↗

PubMed2001

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.

Adaptation, Physiological↗

PubMed2001

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).

Acid Etching, Dental↗

PubMed2001

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.

Adolescent↗

PubMed2001

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.

Adult↗

PubMed2001

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.

Adolescent↗

PubMed2001

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.

Attitude to Health↗

PubMed2001

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.

Adolescent↗

PubMed2001

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.

Algorithms↗

PubMed2001

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.

Adolescent↗

PubMed2000

Identification of matrix metalloproteinases and their tissue inhibitors type 1 and 2 in human masseter muscle.

Changes in masticatory muscle structure and function are either developmental, as seen in anomalies of facial form, or adaptive, as seen during procedures such as orthognathic surgery and functional-appliance orthodontic therapy. Remodelling of muscle extracellular matrix is pivotal in these processes. This turnover is mediated via members of the family of enzymes known as matrix metalloproteinases (MMP) and inhibited by the tissue inhibitors of metalloproteinases (TIMP). The aim here was to investigate the in vivo pattern of expression and distribution of MMPs and TIMPs in masseter muscle of humans with both normal and abnormal facial forms. Masseter muscle biopsies were taken from 10 patients, four with long-face syndrome and six normal controls as confirmed by cephalometry. Immunohistochemical techniques were used to show the pattern and distribution of MMPs and TIMP proteins in the muscle. Zymography of tissue extracts was used to determine the presence of MMP activity. Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the presence of MMP and TIMP-2 mRNA. MMP-1 was expressed around the individual muscle fibres, especially in those fibre surfaces in contact with the interstices of the connective tissue and around blood vessels. MMP-9 staining was less intense and was expressed in the interstices of the connective tissue and around blood vessels. Zymography of protein extracts confirmed that MMP-9 activity was present. MMP-2 and MMP-3 were not expressed in the samples, although MMP-2 mRNA could be detected by RT-PCR and its activity could be detected by zymography. Intense TIMP-1 staining was present around each muscle fibre, in the interstices of the connective tissue and surrounding blood vessels; TIMP-2 mRNA could be detected in all samples. These staining patterns were seen in all biopsies examined and were irrespective of the facial form of the donor. These findings provide evidence that the mechanisms required for matrix remodelling are present in the human masseter muscle.

Adult↗

PubMed2000

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.

Animals↗

PubMed2000

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.

Health Services Needs and Demand↗

PubMed2000

Are orthognathic patients different?

This questionnaire-based study investigated the psychological profile of orthognathic patients prior to starting treatment and compared the findings with a control group of non-patients. Comparison of the data used multivariate multiple regression analysis where outcome variables and independent variables were studied simultaneously. Some differences were found in the psychological profile of the orthognathic patient. They displayed higher levels of state anxiety (P < 0.001), higher numbers of individuals in their social support network (P < 0.05), and lower body image and facial body image (P < 0.001). Self-esteem was also found to be lower, but only at borderline levels of significance (P = 0.052).

Age Factors↗

PubMed2000

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.

Adult↗

PubMed2000

Relationship between utility values and willingness to pay in patients undergoing orthognathic treatment.

OBJECTIVE: To determine utility and willingness to pay (WTP) values for patients undergoing orthognathic treatment in a National Health Service hospital in the United Kingdom and to establish whether WTP values can be used as a measure of strength of preference. PARTICIPANTS: Forty patients who were about to start orthognathic treatment were recruited over a 10-month period between January and October 1998. OUTCOME MEASURES: Utility values were obtained using the standard gamble method and WTP values were determined using a payment card method. The relationship between the two was assessed. RESULTS: The mean utility value was 0.73 and the mean WTP was 6,833 pounds. The correlation between these two measures was -0.46 (P<0.01). CONCLUSIONS: The correlation between the utility and WTP values was in the expected direction thus suggesting that WTP may be used as a measure of strength of preference. Therefore, willingness to pay may be a useful technique to combine with cost utility analysis.

Adult↗

PubMed1999

Long-term application of chincup force alters the morphology of the dolichofacial Class III mandible.

The conventional orthopedic Milwaukee brace exerts a large and continuous force that induces malocclusion and a significant deformation of the mandible. Our previous chincup study examined its use in moderately severe mandibular prognathism without retrusion of the maxilla. The orthopedic force was approximately 500 g at the center of chin and was applied during sleep for 6 to 24 months. For mandibular prognathism subjects (means, 1.0 degrees and -1.3 degrees of ANB angle in the prepubertal and pubertal subjects), the resultant changes were maintained after retention. However, research reported that the changes obtained during chincup treatment (average, 4 (1/2) years' use) were often not maintained in severe skeletal Class III malocclusion. The aim of this clinical study was to investigate the immediate and long-term effects of prolonged use (mean, 7 years 2 months) of chincup appliances in subjects with dolichofacial Class III mandibles. Thirty-six female subjects with severe skeletal Class III malocclusions, associated with large gonial angles, were selected from the dental records of a private clinic. At posttreatment (T1, 65 months' duration) and postretention (T2, 56 months after T1), Ar-Me and Wits appraisal cephalometric parameters were significantly different (P <.01) between patients and control subjects (n = 230). Furthermore, the Go-Me parameter in treated subjects was longer than that of the controls at T0 but became significantly shorter at T2 (P <.01). Treatment was associated with a finding that the Ar-Go parameter increased less than the controls at T2. Our results indicate that long-term use of the chincup appliance (>5 years) is effective in subjects with severe skeletal Class III abnormality.

Case-Control Studies↗