Back to basics: making a vacuum-formed, custom-fitted intraoral mouthguard using the "dry model" technique.
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For a mouthguard to function properly, it must fit well. It is possible to produce a well-fitting mouthguard using the "dry model" technique, which is relatively inexpensive and easy to learn. Custom-fitted intraoral mouthguards help prevent or reduce the severity of concussions as well as minimize oral cavity injuries. (+info)
An appraisal of the Peer Assessment Rating (PAR) Index and a suggested new weighting system.
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The PAR Index was developed to measure treatment outcome in orthodontics. Validity was improved by weighting the scores of some components to reflect their relative importance. However, the index still has limitations, principally due to the high weight assigned to overjet. Difficulties also arise from the application of one weighting system to all malocclusions, since occlusal features vary in importance in different classes of malocclusion. The present study examined PAR Index validity using orthodontic consultant assessments as the 'Gold standard' and clinical ranking of occlusal features and statistical modelling to derive a new weighting system, separate for each malocclusion class. Discriminant and regression analyses were used to derive new criteria for measuring treatment outcome. As a result a new and more sensitive method of assessment is suggested which utilizes a combination of point and percentage reductions in PAR scores. This was found to have better correlations with the 'Gold standard' than the PAR nomogram. (+info)
The effects of increasing the reverse curve of Spee in a lower archwire examined using a dynamic photo-elastic gelatine model.
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This paper describes the development and testing of a dynamic in vitro photo-elastic model for evaluating the effects of orthodontic mechanics on an entire arch of teeth. A model of a mandibular arch was made and the teeth were embedded in a gelatine material with a high level of mechanical creep which permitted tooth movement in response to orthodontic forces. The excellent photo-elastic properties of this material also facilitated the analysis of the stress distribution around the roots of the teeth. The model of a mandibular arch was used to investigate the tooth movements and stress distributions produced by increasing the reverse curve of Spee in a 0.018 x 0.025-inch stainless steel archwire. The results revealed that a 1-mm reverse curve of Spee increased the arch length by 1.6 mm, but increasing the reverse curve of Spee to 5 mm did not increase arch length further. Photo-elastic analysis showed an increased stress distribution around the roots of the incisors and molars as the reverse curve of Spee was increased in the archwire. (+info)
A 3D computer-aided design system applied to diagnosis and treatment planning in orthodontics and orthognathic surgery.
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The purpose of this article is to describe a newly developed 3D computer-aided design (CAD) system for the diagnostic set-up of casts in orthodontic diagnosis and treatment planning, and its preliminary clinical applications. The system comprises a measuring unit which obtains 3D information from the dental model using laser scanning, and a personal computer to generate the 3D graphics. When measuring the 3D shape of the model, to minimize blind sectors, the model is scanned from two different directions with the slit-ray laser beam by rotating the mounting angle of the model on the measuring device. For computed simulation of tooth movement, the representative planes, defined by the anatomical reference points, are formed for each individual tooth and are arranged along a guideline descriptive of the individual arch form. Subsequently, the 3D shape is imparted to each of the teeth arranged on the representative plane to form an arrangement of the 3D profile. When necessary, orthognathic surgery can be simulated by moving the mandibular dental arch three-dimensionally to establish the optimum occlusal relationship. Compared with hand-made set-up models, the computed diagnostic cast has advantages such as high-speed processing and quantitative evaluation on the amount of 3D movement of the individual tooth relative to the craniofacial plane. Trial clinical applications demonstrated that the use of this system facilitated the otherwise complicated and time-consuming mock surgery for treatment planning in orthognathic surgery. (+info)
The influence of maxillary incisor inclination on arch length.
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This ex vivo study was designed to investigate Andrews' hypothesis that there is a space implication when incisors are torqued correctly. A working model was constructed to allow acrylic typodont incisors of varying known values of inclination to be substituted into the model. The arch lengths of the various 'set-ups' were measured using a reflex microscope linked to a PC. In order to quantify the space requirement of clinical relevance for adequate incisor torque, the method was repeated by substituting replicas of patients' 'natural' incisors. For both acrylic and natural incisors it was found that, as the inclination of the teeth increased, there was an increase in all arch lengths, this being greater for the natural incisors. This larger increase for the natural incisors was related not only to their increased size, but was also dependent on the morphology of the incisor. Those incisors which were parallel-sided showed the greatest increase in arch length, whereas the incisors that were relatively triangular in shape showed the smallest increase. When the inclination of an 'average' set of 21/12 is increased by 5 degrees, an increase in the arch length of approximately 1 mm may be expected. (+info)
The effectiveness and efficiency of hygienists in carrying out orthodontic auxiliary procedures.
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The aim of this study was to compare the ability and efficiency of dental hygienists, after preliminary training as orthodontic auxiliaries, with post-graduate orthodontists. The study was cross-sectional and prospective. The sample consisted of five second-year hygienists and five qualified orthodontists from Manchester University Dental Hospital. All subjects carried out a range of orthodontic exercises on phantom head typodonts. The ability and efficiency for each task was measured, and comparison made between hygienists and orthodontic groups. There was no statistically significant differences between hygienists and orthodontists in terms of their ability to carry out potential orthodontic auxiliary procedures. However, orthodontists were more efficient (P < 0.05). The ability of hygienists to carry out potential orthodontic auxiliary tasks after appropriate training is supported. Trained orthodontists are more efficient than newly trained hygienists in carrying out potential orthodontic auxiliary tasks. (+info)
Residual need in orthodontically untreated 16-20-year-olds from areas with different treatment rates.
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Knowledge concerning residual orthodontic need among individuals who have passed the age at which orthodontic treatment is normally provided, is important in the discussion of guidelines for the provision of care. The purpose of the present study was to examine and compare orthodontic need (objective and subjective) in cohorts of orthodontically untreated individuals from areas with various treatment rates. A total of 250 individuals, aged 16-20 years, comprised four samples representing cohorts from areas in Norway with low, medium, and high treatment rates. The occlusion was assessed according to a treatment need index (NOTI) from clinical and radiographic records, and dental cast measurements. Attitudes were assessed from questionnaires addressing satisfaction with dental arrangement, desire for treatment, and value placed upon well-aligned teeth. A significant decrease in occurrence of normative need (P < 0.001) and reported dissatisfaction (P < 0.05) was observed in samples representing increasing treatment rates. Dissatisfaction was completely eliminated among individuals from the high treatment rate area. Although a significant association between severity of malocclusion and desire for treatment existed within samples, this was not reflected in a corresponding trend for a decrease in desire across the samples. Well-aligned teeth seemed to be taken for granted among individuals from the area with a high treatment rate. From the present observations, a 'correct' level of treatment provision could not be identified. (+info)
Initial cleft size does not correlate with outcome in unilateral cleft lip and palate.
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Clinical outcomes in children born with a cleft lip and palate (CLP) have been an area of interest for orthodontists for a number of years. Whilst tools for measurement of these outcomes are available, there is no widely accepted measure of initial cleft severity and no known quantitative indices. Therefore, the potential influence of initial severity remains unmeasured and largely ignored. The aim of this investigation was to determine the importance of initial cleft severity in determining patient outcome. The longitudinal records of 49 children born with a unilateral cleft lip and palate (UCLP), and treated in a single centre were examined. An index of initial cleft severity was developed that categorizes the cleft area as a percentage of the total palate area. The dental arch relationships of the same patients at 6 years of age were also determined. The nature of the association between these was investigated for agreement and correlation by calculation of weighted Kappa and Spearman's correlation coefficient, respectively. No evidence was found in this sample that the initial cleft area had any bearing on the quality of outcome at 6 years of age. (+info)