A comparison of space closure rates between preactivated nickel-titanium and titanium-molybdenum alloy T-loops: a randomized controlled clinical trial.

The purpose of this study was to conduct a prospective randomized controlled clinical trial to evaluate the rate of space closure and tooth angulation during maxillary canine retraction using preactivated T-loops made from titanium-molybdenum alloy (TMA) and nickel-titanium (NiTi). Twelve patients (six males and six females) aged between 13 and 20 years who had upper premolar extractions were included, and each acted as their own control, with a NiTi T-loop allocated to one quadrant and TMA to the other using a split mouth block randomization design. The loops were activated 3 mm at each visit to deliver a load of approximately 150 g to the upper canine teeth. Maxillary dental casts, taken at the first and each subsequent monthly visit, were used to evaluate changes in extraction space and canine angulation. All used T-loops were compared with unused loops in order to assess distortion. Mixed model statistical analysis was used to adjust for confounding variables. The mean rate of canine retraction using preactivated NiTi and TMA T-loops was 0.91 mm/month (±0.46) and 0.87 mm/month (±0.34), respectively. The canine tipping rates were 0.71 degrees/month (±2.34) for NiTi and 1.15 degrees/month (±2.86) for TMA. Both the rate of space closure and the tipping were not significantly different between the two wire types. The average percentage distortion of the TMA T-loop was 10 times greater than that of the NiTi loops when all other variables were matched. There was no difference in the rate of space closure or tooth angulation between preactivated TMA or NiTi T-loops when used to retract upper canines. The NiTi loops possessed a greater ability to retain and return to their original shapes following cyclical activation.

Orthodontic education programs: an international comparison of students' views and experiences.

INTRODUCTION: The purpose of this study was to identify the demographic characteristics of students completing certificate programs in orthodontics, and the curriculum and financial characteristics of orthodontic programs in the English-speaking world. METHODS: An online survey was used to question orthodontic students studying in the 93 programs worldwide in countries where the first language is English. The questionnaire was built by using the online survey tool www.surveymonkey.com, and the students were predominantly contacted directly via e-mail. RESULTS: Of the 301 respondents (an estimated response rate of 33%), the majority were men, had an average age of 29.8 years, and were mostly from programs in the United States. The mean program durations were 31.0 months in the United States and 37.1 months in the Commonwealth, with mean total patient loads of 84 and 106, respectively. Various treatment modalities were used in both groups. The mean annual tuition fee was considerably higher in the United States. The overall mean debt at graduation was $118,200, and the mean expected income 5 years after graduation was $283,200. Private practice was the most popular career path (90.3%), with fewer than a third of the respondents stating that they would consider an academic career. CONCLUSIONS: This study indicates that the demographic characteristics of orthodontic students are similar to those most recently reported, with the proportion of female students continuing to increase. The numbers of transitional dentition patients and total patient case loads are increasing, and students are being exposed to an increasingly wide range of treatment techniques. A continuing increase in tuition fees was reported, along with increased levels of debt at graduation, and fewer students intend to have an academic career.

Moments generated by simple V-bends in nickel titanium wires.

This study compared the moments produced by V-bends placed in rectangular nickel titanium (NiTi) orthodontic wire to those produced in titanium-molybdenum alloy (TMA). V-bends that included angles of 135, 150, and 165 degrees were heat set into 0.017×0.025 and 0.016×0.025 inch NiTi alloy wires and identical bends bent into TMA wires with a dimension of 0.018×0.025 and 0.016×0.022 inch. There were five specimens per group (N=60). The moments produced by each specimen were tested on a custom jig that aligned two lower incisor brackets with zero tip or torque at an interbracket distance of 15 mm. The upper bracket was connected to a moment transducer. The V-bend position for each specimen was varied in 1 mm increments towards the moment transducer. The moments produced by TMA wires were linear, which increased as the V-bend approached the transducer, while NiTi exhibited a non-linear curve characterized by a flattening of the moment value. The point of dissociation (where the moment experienced by the bracket became zero) was estimated for both wire types using linear mixed model analysis. For TMA wires, this point was similar to that reported in the literature but was significantly less for NiTi wire when compared with TMA. The moments produced by TMA generally increased with the magnitude of the V-bend, whereas this was not the case for NiTi.

Changes in malocclusion over time in New Zealand adolescents.

BACKGROUND: The Dental Aesthetic Index (DAI) has been used in many cross-sectional studies of population samples, but its use in assessing changes in malocclusion is less common. The aim of the present study was to describe the natural history of malocclusion and investigate the utility of the DAI as a measure for describing changes in malocclusion in a population-based sample of adolescents. METHOD: A repeat examination was conducted of a sample of 430 children first assessed in 2003 at age 13 and re-examined at age 16 (255 or 59.3 per cent of the baseline sample) with their DAI and orthodontic history recorded at each age. RESULTS: Of the adolescents re-assessed, 28 were in active orthodontic treatment, 30 had completed treatment and 197 had not received any treatment. There were substantial changes in the DAI items from age 13 to 16, with the greatest improvement in maxillary anterior irregularity. Overall, almost one-quarter of participants showed an improvement in their DAI treatment need category which was considerably higher among those who had either received treatment or were in treatment. CONCLUSION: The DAI is a valid and responsive tool for measuring change in malocclusion over time. Anterior mandibular irregularity shows the greatest change with age, and orthodontic treatment is effective in treating malocclusion, at least in the short-term.

Breakages using a unilateral fixed functional appliance: a case report using The Forsus Fatigue Resistant Device.

Fixed functional appliances are designed to provide a simple non-compliant solution to orthodontic Class II treatment. Molar correction can be achieved very quickly using these appliances, but the clinician should be wary of unexpected breakages. This case report documents such an occurrence using a unilateral fixed functional appliance.

The impact of the popular media on cosmetic dentistry.

UNLABELLED: The popular media's influence on social norms with respect to people's appearance is likely to have played a part in the recent growth of cosmetic dentistry. AIMS: This study was designed to investigate the manner in which the popular media have affected the perception and delivery of aesthetic dentistry in New Zealand. METHODS: A nationwide survey was posted to a random sample of 600 general dental practitioners (GDPs) requesting sociodemographic details and information on the types of aesthetic dental procedures provided and the demand for those. Information was also sought on GDPs' awareness of television programmes and reality "makeover" television shows (such as "Extreme Makeover") covering issues related to aesthetic dentistry, together with the impact of such programmes (and that of different print media) on their patients' perceptions of, and demand for, aesthetic dentistry. RESULTS: The response rate was 81.2 percent. A majority of participants perceived an increased demand for tooth whitening (77.8 percent) and veneers (54.8 percent) subsequent to the airing of those television programmes, with 85.2 percent reporting patients mentioning "Extreme Makeover" in relation to aesthetic dentistry. Some 56.8 percent believed that patients had higher aesthetic expectations subsequent to the airing of that programme. An increased demand for tooth whitening was reported by more female than male GDPs, and also by younger practitioners and those who were practising in larger centres. Similar patterns were observed with respect to GDPs recommending tooth whitening for patients. Women's magazines were ranked by GDPs as having the highest impact on patients' perceptions of aesthetic dentistry. CONCLUSION: The popular media (especially television) appear to have had an impact on the demand for various aesthetic dental procedures in New Zealand.

Cephalometric correction factors for bite opening--a dry skull study.

The lateral cephalometric radiograph supplies the clinician with valuable information regarding the facial skeletal morphology of the patient, provided that it is taken correctly. These radiographs should be taken while the patient is occluding in maximum intercuspation, failing which the exposure is often repeated, leading to an increase in patient radiation dose as well as added cost in time and materials. This study investigated the relationship between limited bite opening and selected cephalometric variables. Thirty-one dry skulls were used and five splints were constructed for each skull giving increments of bite opening from 0 to 5 mm. Six lateral radiographs per skull were taken at each increment of bite opening. The radiographs were traced and the points plotted using a reflex metrograph. A linear relationship was found between bite opening and SNB, ANB, SN-mandibular plane, and SN-Y-axis angles. Errors in digitization, superimposition, and landmark identification were determined and found to be acceptable. Regression analysis produced a highly significant (P < 0.001) gradient for each of these angular relationships, allowing a set of correction factors to be produced, which can be applied to bite openings up to 5 mm.

Office reconditioning of stainless steel orthodontic attachments.

An investigation was conducted to determine a simple, effective method for reconditioning stainless steel orthodontic attachments in the orthodontic office. In total, 100 new brackets were bonded to premolar teeth, then debonded and the bond strength recorded as a control for the reconditioning process. The debonded brackets were divided into six groups and each group reconditioned using different techniques as follows: attachments in four groups were flamed and then either (1) sandblasted, (2) ultrasonically cleaned, (3) ultrasonically cleaned followed by silane treatment, (4) rebonded without further treatment. Of the two remaining groups, one was sandblasted, while the brackets in the other were roughened with a greenstone. The brackets were rebonded to the premolar teeth after the enamel surfaces had been re-prepared, and their bond strengths measured. The results indicated that sandblasting was the most effective in removing composite without a significant change in bond strength compared with new attachments. Silane application did not improve the bond strength values of flamed and ultrasonically cleaned brackets. Attachments that had only been flamed had the lowest bond strength, followed by those that had been roughened with a greenstone.