Australian Orthodontic Journal最新文献

For some years there has been unrest in the statistical world regarding the use of the p-value. It has been indicated that the significance of p-values is open to question, which therefore reduces the ability to measure the strength of evidence. This paper examines the use and misuse of the p-value and recommends consideration in its application.

Aim: The aim of the present study was to investigate and compare the cephalometric effects of a conventional Hyrax expansion screw and a memory screw on the skeletal and dentoalveolar structures and soft tissues of the face.

Methods: Thirty-two patients with a maxillary transverse deficiency were divided into two groups. A memory-screw group included 17 patients (nine females and eight males), while a Hyrax-screw group was comprised of 15 patients (eight females and seven males). The mean ages of the subjects in the memory-screw and Hyrax-screw groups were 13.00 ± 1.29 and 12.58 ? 1.50 years, respectively. Lateral cephalograms were taken of the patients at the beginning of the treatment (T1), at the end of expansion (T2) and retention periods (T3). The mean expansion period was 7.76 ± 1.04 days in the memory-screw group and 35.46 ± 9.39 days in the Hyrax-screw group. The Shapiro-Wilk Normality test was used to determine whether the investigated parameters were homogeneous. To determine the treatment changes within the groups, a paired test and Wilcoxon Signed Rank test were applied to the homogeneous and non-homogeneous parameters, respectively. A comparison between the groups was carried out using the Student's t-test for homogeneous parameters and the Mann-Whitney U test for all others.

Results: A results summary indicates that mid-palatal sutural opening and subsequent important skeletal and dental expansions were obtained in all patients. The maxilla moved anteriorly and inferiorly in both groups while the mandible rotated inferiorly and posteriorly but to a greater extent in the memory-screw group.

Conclusion: The newly-developed memory expansion screw takes advantage of rapid and slow maxillary expansion protocols. The suture is opened and the maxilla expanded with relatively lighter forces over a shorter time. The RME using the memory screw resulted in similar sagittal and vertical changes to those produced by the Hyrax screw.

Aims: To compare the analgesic effect of topical benzocaine (5%) and ketoprofen (1.60 mg/mL) after 2 mm activation of 7 mm long delta loops used for maxillary en-masse orthodontic space closure.

Subjects and methods: Twenty patients (seven males, 13 females, 15-25 years of age, mean age of 19.5 years) participated in a randomised crossover, double-blind trial. After appliance activation, participants were instructed to use analgesic gels and record pain perception at 2, 6, 24 hours and 2, 3 and 7 days (at 18.00 hrs), using a visual analogue scale ruler (VAS, 0-4). Each patient received all three gels (benzocaine, ketoprofen, and a control (placebo)) randomly, but at three different appliance activation visits following a wash-over gap of one month. After the first day, the patients were instructed to repeat gel application twice a day at 10:00 and 18:00 hrs for three days. The recorded pain scores were subjected to non-parametric analysis.

Results: The highest pain was recorded at 2 and 6 hours. Pain scores were significantly different between the three groups (Kruskal-Wallis test, p < 0.01). The overall mean (SD) pain scores for the benzocaine 5%, ketoprofen, and control (placebo) groups were 0.89 (0.41), 0.68 (0.34), and 1.15 (0.81), respectively. The pain scores were significantly different between the ketoprofen and control groups (mean difference = 0.47, p = 0.005). All groups demonstrated significant differences in pain scores at the six different time intervals (p < 0.05) and there was no gender difference (p > 0.05).

Conclusion: A significant pain reduction was observed following the use of ketoprofen when tested against a control gel (placebo). The highest pain scores were experienced in patients administered the placebo and the lowest scores in patients who applied ketoprofen gel. Benzocaine had an effect mid-way between ketoprofen and the placebo. The highest pain scores were recorded 2 hours following force application, which decreased to the lowest scores after 7 days.

Despite the fact that recent medical advances have improved the quality of life and increased the life expectancy of patients suffering from thalassaemia, no standard strategy or clinical guidelines are available for the correction of the presenting craniofacial anomalies. The aim of the present study is to review the craniofacial features of affected patients, and to discuss the orthodontic and orthognathic surgical treatment options available to manage the associated and characteristic facial deformity.

Aim: This study was undertaken to assess pre- and post-treatment upper and lower arch dimensions, and changes occurring in those dimensions, during orthodontic treatment without premolar extractions, when finishing wires of a particular material, size and arch form had been used.

Methods: The records of 58 patients (31 male and 27 female) with a mean age of 13.52 (±1.60) years were selected for this study, with ethics approval gained from the Departmental Human Ethics Advisory Group of the University of Melbourne (DHEAG no: 1033997.1). All patients had been treated with fixed appliances (0.018 inch, pre-adjusted edgewise) in the early permanent dentition, without premolar extractions, by one experienced orthodontist. Pre- and post-treatment upper and lower arch dimensions were measured from study casts. Correlation coefficients were calculated between these measurements as well as pretreatment cast and vertical cephalometric measurements, gender and the amount of crowding that had been relieved.

Results: Despite the use of finishing archwires of the same material, size and arch form (0.016 x 0.022 inch, heat-treated cobalt-chromium), there was considerable variation in dimensional changes that occurred during treatment within the total sample and its various subgroups, and in the final arch dimensions. All arch width changes were found to be strongly correlated with the amount of pretreatment crowding. Post-treatment arch dimensions and changes in those dimensions were also strongly correlated with pretreatment dimensions, suggesting that the final post-treatment arch dimensions were significantly influenced by other factors rather than simply the material, size and arch form of the finishing wires. In this treated sample, no statistically significant differences were found in the resultant arch widths and arch width changes occurring in the different vertical pattern sub-groups.

Conclusion: The placement of finishing wires of a particular material, size and arch form is unlikely to result in exactly matching end-of-treatment arch forms and dimensions in all orthodontic patients. Instead, whether using a 0.018 or a 0.022 inch slot system, the clinician should expect considerable individual variation in final arch form and dimension, despite the placement of apparently very similar wires. The main determinants of final arch form and dimension appear to be the original muscular and occlusally-related arch form and dimension and the amount of crowding to be relieved. Final arch forms and dimensional changes with treatment are unlikely to be directly related to patient gender, age or underlying vertical pattern. The findings indicate that clinicians must decide whether they will accept the considerable lateral and antero-posterior expansion that is likely to occur when crowding is to be relieved in the permanent dentition without premolar extractions.

Background: The present case report describes the orthodontic treatment and long-term follow-up of an adult female patient (27 years) who was diagnosed with a mild Class III malocclusion characterised by an anterior and lateral open bite and three periodontally-compromised first permanent molars.

Aim: The aim of treatment was to provide an acceptable aesthetic and functional occlusion while, at the same time, improving the periodontal prognosis.

Methods: The patient was treated with fixed orthodontic appliances utilising direct and indirect skeletal anchorage derived from two mini-screws placed in the palate and one mandibular buccal mini-screw.

Results: The objectives of good aesthetics, a functional occlusion, a healthy periodontium and a balanced profile were achieved. The total treatment time was 31 months, which comprised 13 months of maxillary fixed labial appliances and 25 months of mandibular fixed labial appliances. The three-year follow-up records showed stability of the Class ILL correction.

Introduction: The aim of this study was to evaluate the dentoskeletal effects of a modified slow maxillary expansion appliance (MSMEA) during the transition from the mixed to the permanent dentition.

Methods: Forty subjects presenting with posterior crossbites were divided into two groups. Twenty-three subjects were assigned to a treatment group (mean age: 9.45 years) and 17 subjects assigned to a control group (mean age: 9.25 years). An MSMEA with acrylic occlusal coverage limited to the palatal cusps was used to provide maxillary expansion. The mean slow expansion treatment period was 7.8 months, while the mean observation period continued for 14.8 months of a 22.6-month total study period.

Results: Substantial dental and skeletal effects were observed following treatment with the MSMEA. Most maxillary inter-molar and deciduous inter-second molar width increases were maintained in the permanent dentition (91% and 97%, respectively). Skeletal maxillary transverse dimensions, which increased by 2 mm after active expansion, were significantly greater (p < 0.001) when compared with the controls.

Conclusion: The findings suggested that an MSMEA provided orthopaedic and dental effects as a result of posterior crossbite correction. The effects of the appliance seen during the mixed dentition were maintained in the permanent dentition.

Background: There are few reports of the socio-demographic and malocclusion characteristics of those undergoing clinical orthodontic treatment in private specialist practice.

Aim: To describe the pretreatment characteristics of individuals presenting for orthodontic treatment.

Methods: Individuals (N = 174) presenting for orthodontic treatment in 19 private specialist orthodontic practices in New Zealand were randomly selected and examined (at the beginning of a three-year prospective study) and their malocclusions compared using the Dental Aesthetic Index (DAI).

Results: The mean DAI score was 35.8 (SD 8.4). There were no statistically significant socio-demographic differences in DAI score other than by household-based socio-economic status (SES), whereby mean scores were considerably higher in those of low SES. The majority of patients attending for treatment had severe or very severe/handicapping malocclusions. Females had less severe malocclusions than males, on average, although the difference was not statistically significant.

Conclusions: The malocclusion severity threshold for seeking orthodontic treatment appears to be higher in those of lower SES. The study findings highlight the need to improve access to orthodontic treatment for this group.

Aim: To determine the features of the mandibular dental arch in subjects presenting with impacted permanent lower canines.

Methods: The 'impaction group' consisted of 48 Indian subjects with mandibular canine impaction (Females:Males, 1.5:1; mean age, 15.03 ± 0.49 years). The 'control group' was comprised of 96 age-, gender- and malocclusion-matched Indians who were randomly selected from subjects initially screened but who had completely erupted mandibular canines. Arch width, arch length, arch shape and space status (total tooth size, arch-length--tooth-size discrepancy) were assessed using dental models and were compared between the groups using comparative measurements and statistics.

Results: Statistically significant differences were demonstrated with respect to the arch length, arch shape, total tooth size and arch-length--tooth-size discrepancy (p = 0.03, 0.02, 0.04, 0.01; independent 2-sample t-tests, respectively). Crowding was more prevalent in subjects with impaction than in the controls, with the difference being statistically significant (chi-square = 13.202; degrees of freedom (df) = 4; p = 0.010).

Conclusion: Patients with permanent mandibular canine impaction have adequately wide but shorter lower dental arch forms along with wider mandibular total tooth size and greater arch-length--tooth-size discrepancy when compared with a control sample.