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The assessment of quality of life is becoming increasingly important in dentistry. This may be measured using two groups of instruments: generic and condition-specific. OBJECTIVES: This paper describes the processes of validity and responsiveness testing of a condition-specific quality of life measure for patients who present with severe dentofacial deformity requesting orthognathic treatment (the so-called Orthognathic Quality of Life Questionnaire). The development of the instrument is described in a previous paper. METHOD: The OQLQ was tested for validity using a visual analogue scale and also the Short-Form 36 health survey questionnaire. Responsiveness was tested using longitudinal data obtained before, during and after orthognathic treatment. RESULTS AND CONCLUSIONS: The OQLQ shows good evidence of validity and responsiveness. This, together with previous evidence of good reliability, suggests that the instrument may prove useful in both clinical trials and in quality assurance. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

The aims of this study were to measure the volume, cross-sectional area, thickness, width, and length of contracted masseter muscles in a sample of adults, four males and six females, using three-dimensional (3D) ultrasonography, and to correlate these measurements with the variations in facial morphology of the sample. The scans were carried out bilaterally using a hand-held probe carrying a magnetic positional sensor, which enabled a computer to reconstruct the images into a 3D array of slices. Measurements were made by the computer from the reconstructed images using specially written software. Cephalometric analysis initially involved seven angular, eight linear, and two proportional variables, but as these were strongly inter-dependent, the variables were reduced to four principal components prior to statistical comparison with the mean muscle variables. The values found for muscle volume, cross-sectional area, and thickness were broadly consistent with those of previous investigators. Volume showed a significant, negative correlation with mandibular inclination including gonial angle (P ≤ 0.001), and a significant, positive correlation with total posterior face height and ramus height (P ≤ 0.001), and lower posterior face height percentage (P ≤ 0.01). Weaker correlations were found for length and thickness. While the results support existing evidence that large masticatory muscles are associated with brachycephalism and vice versa, a cautious interpretation is necessary in view of the small sample size. The 3D ultrasonography system is at an experimental stage and requires further development and evaluation. [ABSTRACT FROM AUTHOR]

Objective: To carry out a UK national clinical audit of orthognathic acceptance criteria and information provided to orthognathic patients before treatment., Design: National clinical audit., Setting: Data collected using Bristol Online Surveys., Participants: Sixty-nine UK hospital orthodontic departments submitted data., Methods: Data were collected at two time points using Bristol Online Surveys over a period of 12 months. These were before treatment at the first multidisciplinary clinic (MDT) and immediately after surgery. The data collected included: Index of Orthognathic Functional Treatment Need (IOFTN); Index of Orthodontic Treatment Need (IOTN); age; previous orthodontic treatment; attendance at an MDT; treatment times; and information provision., Results: Eighty-five units agreed to take part in the audit with 69 submitting data, giving a response rate of 81%. The data from 3404 patients were uploaded, 2263 before treatment and 1141 immediately after surgery. Of patients, 91.07% had an IOFTN score of 4 or 5 and 88.73% had an IOTN score of 4 or 5. The mean age at the first MDT was 22 years in the first cohort and 21 years and 4 months in the second immediate post-surgery cohort. Of patients, 37.93% had undergone some form of previous orthodontic treatment, but only 0.28% had undergone previous orthognathic treatment; 96.93% had an MDT confirm that orthodontic treatment by itself was insufficient to adequately correct their functional symptoms. The average treatment time from bond up to surgery was 2 years and 6 months. With respect to information provision, patients received information from a number of sources, principally the British Orthodontic Society (BOS) patient information leaflets and the BOS website Your Jaw Surgery., Conclusions: In the UK, the majority of orthognathic cases fulfil the criteria for acceptance for NHS-funded orthognathic treatment, as outlined by the Chief Dental Officer's interim guidance on orthognathic treatment. This suggests any prior approval process would not be a good use of NHS resources in the commissioning of orthognathic treatment.

Objective: To investigate the effect visual imagery may have on career choice among current university students across a range of subjects and disciplines., Setting: University College London (UCL), UK., Design: Cross-sectional questionnaire-based study., Participants: The study compared four main groups of UCL students: current students at the Slade School of Fine Art; UCL Eastman Dental Institute; UCL Bartlett School of Architecture; and the Faculty of Laws., Method: A questionnaire based on the Vividness of Visual Imagery Questionnaire (VVIQ) was distributed along with questions regarding demographic information., Results: There were no significant differences between the VVIQ scores across the four included Schools/Faculty: The Slade School of Fine Art; UCL Bartlett School of Architecture; Faculty of Laws; and UCL Eastman Dental Institute, F (3,219) = 2.160, P = 0.094. There were also no significant differences in the scores for the Eastman ( M = 60.21, SD = 13.58) and the three other Schools/Faculty ( M = 62.87, SD = 10.96); t(-1.317) = 221, P = 0.189, and no significant difference in the scores for the Orthodontic students ( M = 60.80, SD = 13.39) and the remaining other included students ( M = 61.44, SD = 9.68); t(-0.232) = 221, P = 0.817. Aphantasia was uncommon in this sample, with a prevalence of 0.9%. A positive correlation was found between age group and total VVIQ score, with older participants scoring higher on the VVIQ. Women were significantly more likely to say that their ability to visualise had affected their career choice than male respondents., Conclusions: There were no significant differences between the VVIQ scores across the four included Schools/Faculty. Visual imagery ability did not differ in dental or orthodontic students in comparison to other student groups. Further work is needed to replicate these findings in more diverse samples.

Objective: To investigate the treatment outcome in terms of the malocclusion features and the changes in the occlusion of patients undergoing orthodontic/orthognathic treatment using the Peer Assessment Rating (PAR) and the Index of Complexity, Outcome and Need (ICON) and to test the application of the Index of Orthognathic Functional Treatment Need (IOFTN) on this sample as a measure of orthognathic pre-treatment need., Design: Retrospective longitudinal cohort study., Setting: The orthodontic department at the Eastman Dental Hospital., Material and Methods: The study models of a sample of 100 orthodontic/orthognathic patients who were treated at the Eastman Dental Hospital were measured using the PAR index and ICON at three stages: pre-treatment, pre-surgery and at debond. Treatment need was assessed by measuring IOTN and IOFTN using start study models., Results: 99% of the sample showed an improvement in PAR score, with 82% of the sample being greatly improved. ICON showed that 95% of the sample had an improvement of different degrees with 5% being not improved or worse. The IOFTN qualified 97% of the patients for orthognathic treatment when used retrospectively on the sample while the DHC of IOTN qualified the whole sample for orthodontic treatment., Conclusions: Orthodontic/orthognathic treatment showed improved and acceptable overall results. The PAR index and ICON were valid measures to investigate the outcome of orthognathic treatment. IOFTN proved to be a useful tool in determining and prioritizing orthognathic treatment based purely on functional need.

Skeletal muscle defects are notoriously difficult to manage and the current methods used are associated with many limitations. Engineered skeletal muscle tissue has the potential to provide a solution that circumvents these disadvantages. Our previous work has identified a novel three-dimensionally aligned degradable phosphate glass fibre scaffold that can support myoblast differentiation and maturation. This current study has further developed the scaffold by encasing the fibres within a collagen gel to produce a smart composite scaffold that provides key biomimetic cues and supports the formation of a tissue that may be implanted in vivo. The constructs formed were approximately 30 mm long and microscopic examination confirmed favourable unidirectional cell alignment. There was good cell survival, and gene expression studies demonstrated upregulation of the myogenic regulatory factors and developmental and adult myosin heavy chain isoforms indicating myofibre formation and maturation respectively. Compared with the three-dimensional glass fibre scaffolds, the composite scaffolds had later gene upregulation, however, the use of collagen gels reinforced with degradable aligned glass fibres offers the opportunity to create a tissue analogue that can be easily manipulated. Furthermore, the glass fibre ends could support tendon/bone formation, and the channels formed as the fibres degrade could allow for vascular ingrowth., (Copyright © 2013 John Wiley & Sons, Ltd.)

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.

Staphylococci species have been isolated from removable orthodontic retainers. The aims of this study were to determine the most suitable device to analyze surface roughness of autopolymerized acrylic and thermoplastic materials and whether the surface dynamics of these materials influences the attachment of Methicillin-Resistant Staphylococcus aureus (MRSA). Clinically simulated samples of autopolymerized acrylic and thermoplastic material were first evaluated using laser non-contact, stylus mechanical profilometries and atomic force microscopy (AFM) followed by contact angle measurement to characterize their surface dynamics. Finally, an in vitro biofilm assay was carried out using a constant depth film fermentor to assess biofilm attachment. The results showed a significant difference between the roughness values obtained from the tested profilometers with the AFM exhibiting the most consistent roughness values. MRSA tended to accumulate initially within the microscopic irregularities of autopolymerized acrylic samples whereas acid-base and electron donor interactions influenced the bacterial attachment onto the thermoplastic samples.

Tissue engineering has the potential to overcome limitations associated with current management of skeletal muscle defects. This study aimed to sequentially identify a degradable phosphate glass scaffold for the restoration of muscle defects. A series of glass compositions were investigated for the potential to promote bacterial growth. Thereafter, the response of human craniofacial muscle-derived cells was determined. Glass compositions containing Fe4- and 5 mol% did not promote greater Staphylococcus aureus and Staphylococcus epidermidis growth compared to the control (p > 0.05). Following confirmation of myogenicity, further studies assessed the biocompatibility of glasses containing Fe5 mol%. Cells seeded on collagen-coated disks demonstrated comparable cellular metabolic activity to control. Upregulation of genes encoding for myogenic regulatory factors (MRFs) confirmed myofibre formation and there was expression of developmental MYH genes. The use of 3-D aligned fibre scaffolds supported unidirectional cell alignment and upregulation of MRF and developmental MYH genes. Compared to the 2-D disks, there was also expression of MYH2 and MYH7 genes, indicating further myofibre maturation on the 3-D scaffolds and confirming the importance of key biophysical cues., (Copyright © 2012 John Wiley & Sons, Ltd.)

Objective: To design a new index categorizing the functional need for orthognathic treatment., Design: Laboratory-based study., Setting: Records were obtained from two UK hospital-based orthodontic departments., Participants: A panel of four consultant orthodontists, experienced in providing orthognathic care, devised a new index of Orthognathic Functional Treatment Need (IOFTN) with the aid of the membership of the British Orthodontic Society Consultant Orthodontists Group (COG). Twenty-three consultants and post-CCST level specialists took part in the study as raters to test the validity and reliability of the new index., Methods: A total of 163 start study models of patients who had previously undergone orthognathic treatment were assessed by the panel of four consultant orthodontists using the new index (IOFTN) and the agreed category was set as the 'gold standard'. Twenty-one consultants and post-CCST level specialists then scored the models on one occasion and two scored 50 sets of models twice to determine the test-re-test reliability., Results: Kappa scores for inter-rater agreement with the expert panel for the major categories (1-5) demonstrated good to very good agreement (kappa: 0·64-0·89) for all raters. The percentage agreement ranged from 68·1 to 92% in all cases. Intra-rater agreement for the major categories was moderate to good (kappa: 0·53-0·80)., Conclusions: A new index, the IOFTN, has been developed to help in the prioritization of severe malocclusions not amenable to orthodontic treatment alone. It demonstrates good content validity and good inter-rater and moderate to good intra-rater reliability. As a result of being an evolution of the IOTN, the familiar format should make it easy to determine functional treatment need within daily orthognathic practice., (© 2014 British Orthodontic Society.)

A hypofunctional masticatory system was developed in 21-day-old male rats by feeding them a soft diet for 27 weeks. Retraining of a parallel group for 6 weeks was achieved by switching back to a hard diet after 21 weeks. A control group was fed a hard diet for 27 weeks. At the end of the experimental period, the expression levels of the myosin heavy chain isoform genes MYH 1 and 2 (fast), 3 (embryonic) and 7 (slow) in the deep masseter were compared using qRT-PCR analysis. The gene expressions of MYH 3 and MYH 7 were significantly higher in the rehabilitation group compared with the normal and hypofunctional group, but no significant differences were found in regards to the gene expression of MYH 1 and 2. Retraining made it possible for the slow (MYH 7) isoform levels to adapt to the increased mechanical load. The increased level of embryonic (MYH 3) isoform could be due to the need of creation of new MYH isoforms.

Objective: To determine the influence of the occlusal plane angle on smile attractiveness as perceived by a group of adult orthodontic patients and dentists., Materials and Methods: The first stage utilized a laboratory approach to record changes in vertical tooth position at different occlusal plane angles using a maxillary model mounted on an articulator. In the second stage, photographic manipulation was undertaken, using data from stage 1, to produce a computerized prediction of the appearance of the smile at differing occlusal plane angles (0, 5, 10, 15, and 20 degrees). Finally, the five developed photographs were assessed by participants., Results: Alterations in the occlusal plane angle did affect relative smile attractiveness for both patients (n  =  66) and dentists (n  =  66). For patients, the 10 degree smile was rated better than the 0 and 20 degree smiles (P < .01); for dentists, the 15 degree smile was rated better than the 0 and 20 degree smiles (P < .01). The 5, 10, and 15 degree smiles were indistinguishable for patients, and the 10 and 15 degree smiles were indistinguishable for dentists., Conclusion: Changing the occlusal plane angle does affect relative smile attractiveness. However, patients were more tolerant of these changes than dentists. This suggests that large changes in the occlusal plane angle would affect relative smile attractiveness, and small changes are unlikely to affect smile attractiveness.

Objectives: To use various facial classifications, including either/both vertical and horizontal facial criteria, to assess their effects on the interpretation of masseter muscle (MM) gene expression., Materials and Methods: Fresh MM biopsies were obtained from 29 patients (age, 16-36 years) with various facial phenotypes. Based on clinical and cephalometric analysis, patients were grouped using three different classifications: (1) basic vertical, (2) basic horizontal, and (3) combined vertical and horizontal. Gene expression levels of the myosin heavy chain genes MYH1, MYH2, MYH3, MYH6, MYH7, and MYH8 were recorded using quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and were related to the various classifications. The significance level for statistical analysis was set at P ≤ .05., Results: Using classification 1, none of the MYH genes were found to be significantly different between long face (LF) patients and the average vertical group. Using classification 2, MYH3, MYH6, and MYH7 genes were found to be significantly upregulated in retrognathic patients compared with prognathic and average horizontal groups. Using classification 3, only the MYH7 gene was found to be significantly upregulated in retrognathic LF compared with prognathic LF, prognathic average vertical faces, and average vertical and horizontal groups., Conclusion: The use of basic vertical or basic horizontal facial classifications may not be sufficient for genetics-based studies of facial phenotypes. Prognathic and retrognathic facial phenotypes have different MM gene expressions; therefore, it is not recommended to combine them into one single group, even though they may have a similar vertical facial phenotype.

Objectives: The aim of this study was to determine whether the morphology of three different self-ligating brackets affects the accuracy of their positioning when compared with a conventionally ligating bracket., Design: An ex vivo prospective comparison of the accuracy of positioning self-ligating brackets with conventionally ligating brackets., Setting: Orthodontic Department, Eastman Dental Institute, London, UK., Subjects and Methods: Twenty-five clinicians with 2 or more years experience of bracket placement bonded four identical typodont malocclusions with Damon MX(TM), In-Ovation System R(TM) and SmartClip(TM) self-ligating brackets and also Victory Series(TM) conventionally ligating brackets. Four hundred brackets of each type were positioned. Vertical, horizontal and angular bracket position errors were assessed by reference to the FA point and FACC respectively, using digital images and image analysis software., Results: Method error analysis showed no evidence of bias and minimal random error. The Victory Series brackets were the most accurately positioned. Although the amount of positioning error for all the self-ligating brackets was small, a greater number were positioned outside vertical and horizontal tolerance limits compared to the conventionally ligated brackets (P<0·001). The Damon MX bracket type was nearly 10 times more likely to be inaccurately placed relative to the FA point compared with the Victory Series bracket. The differences relating to angular positioning error were not statistically significant (P>0·05)., Conclusion: The findings indicate that the positioning of three types of self-ligating brackets was less accurate than the conventional pre-adjusted edgewise bracket, when using a direct bonding technique. This may have implications for their clinical application.

The Orthognathic Team at the Eastman Dental Hospital has developed a new style of multidisciplinary clinic to supplement the traditional orthognathic consultation. The aim of the new clinic is to increase patient satisfaction and involvement in the consent and decision making process, as well as optimizing the information given to prospective patients regarding all aspects of this complex elective treatment. Results of a survey of patients attending the clinic found that 80% thought that the information given was 'just the right amount' and 96% were satisfied with the new structure. They particularly found it useful to meet a patient who had completed treatment. All of those who attended said that they understood the information given to them and would recommend the clinic to those considering orthognathic treatment. They also liked having other patients there with them on the clinic.

Objectives: To determine the skeletal relationships in patients with hypodontia and analyze the effects of severity and pattern., Materials and Methods: Pretreatment lateral cephalograms from 277 patients with hypodontia, categorized by the number of missing teeth as mild (1-2), moderate (3-5), or severe (> or =6), were digitized recording angular measurements and ratios and compared with published norms matched for age and gender. Pattern was determined as mandibular, maxillary, bimaxillary, bilateral, anterior, posterior, and anteroposterior. Linear regression models assessed relationships between number of missing teeth and cephalometric parameters, controlling for the pattern of hypodontia., Results: For every additional missing tooth, SNA, SNB, and ANB decreased 0.3 degrees , 0.1 degrees , and 0.2 degrees , respectively; this was clinically significant for >4, >10, and >5 missing teeth, respectively. Mandibular to cranial base ratio decreased 0.3% for every additional missing tooth; this was clinically significant for >10 missing teeth. The MMPA decreased 0.3 degrees for every additional missing tooth; this was clinically significant for >7 missing teeth. Percentage LAFH decreased 0.2% for every additional missing tooth; this was significant for >7 missing teeth. Jarabak ratio increased 0.2% for each additional missing tooth; this was clinically significant for >10 missing teeth. Anterior hypodontia significantly decreased most cephalometric parameters., Conclusions: Patients with hypodontia demonstrated a tendency toward a Class III relationship, caused by decreased maxillary and mandibular angular prognathism and MnCB ratio, though the effect was greater on the maxilla than the mandible. Clinical significance was only associated with severe hypodontia. Vertically, there was a tendency toward decreased MMPA and %LAFH; this was clinically relevant only with severe hypodontia. Anterior hypodontia had a significant effect on skeletal relationship.

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.

There is a clearly established relationship between masticatory muscle structure and facial form. Human studies in this area, however, have been limited, especially in consideration of the myosin heavy chain (MyHC) family of contractile proteins. The aim of this pilot study was to assess if differences were detectable between genotype with respect to MyHC isoforms and the vertical facial phenotype in a sample of nine Caucasian female patients, age range 18-49 years, using a novel rapid technique. Masseter muscle biopsies were taken from patients with a range of vertical facial form. The levels of expression of the MyHC isoform genes MYH 1, 2, 3, 6, 7, and 8 were compared with the expression in a female calibrator patient aged 23 years with normal vertical facial form, using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Statistical analysis was undertaken using Pearson correlation coefficient. The results showed that there were distinct differences in gene expression between patients with a wide range of variation although changes in MYH1 were consistent with one cephalometric variable, the maxillo-mandibular angle. The full procedure, from start to finish, can be completed within half a day. Rapid genotyping of patients in this way could reveal important information of relevance to treatment. This technology has potential as a diagnostic and prognostic aid when considering correction of certain malocclusions.

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.

Background Information: Functional adaptation of skeletal muscle is a requirement for different muscle groups (e.g. craniofacial, ocular and limb) to undergo site-specific changes. Such tissue remodelling depends on dynamic interactions between muscle cells and their extracellular matrix, via participation of multifunctional molecules such as integrins. In view of data suggesting a role in fundamental muscle biology and muscle development in other systems, the present study has focused on expression and function of alpha v integrins, in cultured adult human craniofacial muscle (masseter) precursor cells and myotubes, and the predominantly fibroblastic IC (interstitial cells) population., Results and Conclusions: Flow-cytometric phenotyping and immunofluorescence phenotyping show that alpha v, alpha v beta 3 and alpha v beta 5 are expressed in all mononuclear cells (muscle precursors and IC) seeded on muscle extracellular molecules such as gelatin, VN (vitronectin) and FN (fibronectin). In this system, blockade of alpha v activity using a function-perturbing antibody abrogates cell migration on VN and FN. alpha v integrins act predominantly as VN receptors as cell-substrate attachment is diminished when alpha v neutralizing agents are introduced into cultures seeded on VN, and this inhibition is reversible; these integrins also appear to be minor FN receptors. These results demonstrate that the alpha v subset of integrins present on both myogenic precursors and IC is an essential cohort of VN and, to a lesser extent, FN receptors mediating cell adhesion and, either directly or indirectly, arbiters of cell motility.

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.

The objective of this study was to determine differences in behavior and attitudes of dentists in Riyadh, Saudi Arabia, in providing orthodontic care for children who are sensory impaired. A self-administered questionnaire was sent to all dentists working in Riyadh to assess the following domains: personal characteristics of the dentists and their practices, provision of dental care for children who are visually-impaired (Vl) and/or hearing-impaired (HI), and their attitude toward providing orthodontic care for these children. Attitudes were measured on two scales and the overall score of these two scales represented each respondent's attitude. Thirty percent of the dentists provided dental care for children with VI and 45.3 percent did for children with HI. The provision of orthodontic care was significantly affected by the country in which the dentists had received their dental training, both for children with VI and HI (p < 0.01), and by number of years they had been in practice for children with VI (p < 0.05). Regression analysis showed that only the country of dental training significantly affected the dentist's attitude score. There were also significant variations in attitudes toward the provision of orthodontic treatment for children with sensory impairment (SI), influenced by dental training and experience. In practical terms, this means that improvement in attitudes needs to be initiated at the dental undergraduate level. Establishing global guidelines for the provision of orthodontic treatment for patients with sensory impairment is likely to assist both professionals and patients.

The aim of this study was to investigate the in vitro response of human craniofacial muscle-derived myotubes (primitive/nascent muscle fibres), in three-dimensional constructs, to strain in vitro to mimic clinical scenarios, using expression of the mechanoresponsive gene gelatinase-A/matrix metalloproteinase-2 (MMP-2) as a marker of remodelling of muscle extracellular matrix. Three-dimensional (3D) constructs of cells derived from explants of human masseter muscle (human craniofacial muscle-derived cells; hCMDC) in collagen sponges were subjected to mechanical, uniaxial strain using the Bio-Stretch system. 3D myotube constructs were exposed to the strain regimes of rapid ramp stretch (RRS) or cyclical ramp strain (CRS) with 7.5% and 15% strain. The activity of MMP-2 was assessed by zymography of construct-conditioned medium, whilst lysates of the constructs were used to measure creatine phosphokinase (CPK) activity to confirm the presence of myotubes in the strained constructs. Scanning electron microscopy of the collagen sponges and the CPK assays confirmed the presence of myotubes. MMP-2 was expressed by all the samples and controls, but expression was found to be significantly higher in those cultures strained continuously (RRS), compared to cyclical strain (CRS), and in those strained at 15% compared to 7.5%. Thus, MMP-2 expression, and hence extracellular matrix remodelling, is up-regulated in response to strain and is dependent upon the amount and type of strain to which the muscle is subjected., ((c) Eur J Oral Sci, 2005)

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.

Skeletal muscle has been well characterized as a reservoir of myogenic precursors or satellite cells with the potential to participate in cellular repopulation therapies for muscle dysfunction. Recent evidence, however, suggests that the postnatal muscle compartment can be considered an alternative to bone marrow as a source of multipotent cells or muscle-derived stem cells (MDSCs). MDSCs, when primed with appropriate environmental cues, can differentiate into a variety of non-muscle cells. The present study describes the application of a new technique for the isolation of adult human myoblasts and putative MDSCs, based on microbead-immunomagnetic selection of CD56+ cells, derived from craniofacial skeletal muscle, and details changes in morphological/molecular phenotype of the purified cells when maintained in either a myogenic or a non-myogenic milieu. Multiple immunofluorescence microscopy and two-colour flow-cytometric analysis of proliferating CD56+ cultures revealed positive staining for myogenic markers (CD56, desmin and M-cadherin) as well as putative stem-cell markers [the antigens CD34, CD90 and CD106, and Flk-1 (fetal liver kinase-1)/VEGFR-2 (vascular-endothelial-growth-factor receptor)]. Confluent cultures subjected to cycles of adipogenic or osteogenic induction contained either adipocytes or osteoblasts and myotubes. In conclusion, the CD56+ subpopulation within adult human skeletal muscle is heterogeneous and is composed of both lineage-committed myogenic cells and multipotent cells (the candidate MDSCs), which are able to form non-muscle tissue such as fat and bone.

A questionnaire was sent to the parents of 77 visually impaired (VI), 210 hearing impaired (HI) and 494 control children seeking their views on their child's dental appearance, orthodontic treatment need and issues that might influence the child undertaking treatment. The parents' views were compared with a dentist's assessment of treatment need using the Index of Orthodontic Treatment Need (IOTN). There was disagreement between the dentist's assessment and the parents' perceptions in all groups. However, the least disagreement was seen in the HI group. There was a statistically significant (P < 0.05) association between control and HI parents' views of their children's treatment needs and their opinion on their dental appearance. Most parents thought that orthodontic treatment was difficult to obtain and expensive and that their child would find difficulty coping with the treatment. Furthermore, parents of VI children considered that treatment was unlikely to be undertaken due to their child's reduced concern for their appearance. The study indicates that the awareness of treatment need for VI and HI children differs between their parents and dentists.

A mathematical formula based on a geometric model is described that will permit greater accuracy in planning orthodontic treatment and orthognathic surgery for patients who require differential maxillary impaction.

- 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.

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 racial differences in the craniofacial structures of 28 Japanese and 24 British Caucasian females with Class III malocclusions associated with a severe skeletal pattern were examined using lateral cephalograms. The mean age of the Japanese and Caucasian patients was 19.6 +/- 3.5 and 20.2 +/- 3.8 years (+/- SD), respectively. The mean values of 14 linear and 13 angular cephalometric parameters were compared between the two groups. The results showed that the Japanese females had a significantly reduced anterior cranial base (P < 0.01), a more retrusive midfacial component (P < 0.05), and a significantly increased lower anterior facial height (P < 0.01) associated with a more obtuse gonial angle (P < 0.05) compared with the Caucasians. Analysis of the dento-alveolar component in Japanese patients indicated more proclined upper incisors (P < 0.01) compared with those of Caucasian subjects. The reduced anterior cranial base and midfacial component, and the high-angle facial pattern in the Japanese population, may be morphological features based on race, and these skeletal features seem to be less favourable for a skeletal Class III growth pattern compared with the Caucasian population.

The craniofacial features of 49 Japanese and 75 British Caucasian girls with Class II division 1 malocclusions were evaluated from lateral cephalometric radiographs, and the morphological differences between both races were examined. The subjects' ages ranged from 11 years 1 month to 12 years 11 months. The mean values of 13 linear and 13 angular cephalometric parameters were compared. The Japanese Class II division 1 sample had a significantly shorter anterior cranial base length (S-N; P < 0.001) and a more obtuse articular angle (S-Ar-Go; P < 0.001). Analysis of the dentoalveolar components in Japanese subjects showed more proclined lower incisors (L1/Go-Me; P < 0.05) and a steeper occlusal plane (Occ.P/S-N; P < 0.01) relative to those of Caucasians. The short anterior cranial base length and excessive vertical development in the Japanese population might be common racial morphological features, but the main reason for the Class II division 1 skeletal disharmony in both races was different; it was caused by the anteriorly positioned maxilla in Caucasians and the backward rotated mandible in the Japanese.

There has been tremendous progress in orthodontics since Edward Angle first popularised the fixed orthodontic appliance at the turn of the century. Recent years have seen an increased demand for orthodontic treatment from both adolescents and adults and, in addition, patient and clinician expectations of treatment outcomes continue to rise. A desire for more aesthetic materials has resulted in both smaller and 'tooth-coloured' appliances. Improvements in technology, often outside orthodontics, have also led to the development of new materials. The best example of this was the development of nickel titanium alloy by the NASA space programme, which was subsequently adapted for use in nickel titanium archwires. Other technological advances adopted for use in orthodontics include magnets, computerised imaging systems and distraction osteogenesis. This review paper looks at some of the innovations in the fields of materials as well as in techniques and appliance systems.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

The purpose of this study was to investigate the effect of surface roughness on the relative corrosion rates of wires of four alloys-stainless steel, nickel titanium, cobalt chromium, and beta titanium. Batches of wire were divided into two groups. Wires in one group were industrially polished to provide a uniform surface finish; wires in the other group were left for comparison "as received." Wire diameter, hardness, and relative corrosion rates were compared within groups before and after polishing. Comparisons were also made across the four groups of alloys. The samples of as-received wires showed variations in surface finish, with beta titanium having the roughest appearance and cobalt chromium the smoothest. Nickel titanium and stainless steel surfaces were similar. Polishing provided a more uniform finish, but significantly reduced the diameter of the wires. Microhardness testing of wire surfaces of each alloy indicated that no significant work-hardening occurred as a result of polishing. The relative corrosion rates (expressed in terms of corrosion current density) in a 0.9% sodium chloride solution were estimated using the electrochemical technique of polarization resistance. Nickel titanium wires exhibited the greatest corrosion current density in the as-received state. Polishing significantly reduced the corrosion rate of nickel titanium, such that comparison between the four alloys in the polished state revealed no significant difference in their relative corrosion rate/corrosion current density.