Australian Orthodontic Journal最新文献

Background: The present investigation was designed to determine the location and severity of root resorption associated with impacted maxillary canine teeth using cone beam computed tomography (CBCT). A secondary aim was to identify possible influencing factors.

Methods: The radiological reports of 183 patients, radiographed with a small-volume CBCT focussed on the impacted maxillary canine teeth, were assessed. Eighty-five patients had resorption associated with the impaction. The CBCT image datasets were viewed to determine the location and severity of the lesions.

Results: A total of 110 impacted maxillary canine teeth resorbed 120 adjacent teeth, including 14 premolars and one permanen molar. The apical third and palatal surface were commonly involved. Fifty per cent of the resorptive lesions were mild, 20% moderate and 30% severe. There was no significant relation between age or gender on the number, location or severity of resorption. There was a statistically significant correlation between the number of impacted canine teeth an'd the number of teeth resorbed, as well as the tooth type and the surface involved in the resorption.

Conclusions: All root levels and surfaces of teeth associated with impacted maxillary canine teeth can be resorbed to different levels of severity. Neither age nor gender influences the number, location or severity of the resorption.

Background: The extraction of an upper lateral incisor for orthodontic purposes is rare and must be adequately justified.

Aim: The present case report describes the management of a skeletal Class II crowded malocclusion that was facilitated by the extraction of upper lateral incisors and lower first premolars.

Methods: A 14-year-old male patient presented with a skeletal Class II crowded malocclusion with associated speech and chewing difficulties. Phase I of treatment involved the extraction of the upper lateral incisors and functional appliance therapy. Phase II included the extraction of lower first premolars and mechanotherapy using full fixed appliances.

Results: An improvement in aesthetics and sagittal relations was achieved during phase I therapy as the mandible was advanced over a period of eight months. Mandibular skeletal change was 6.5 mm observed at pogonion. During phase II therapy, the maxillary canines were substituted for lateral incisors and a functional occlusion was achieved. The skeletal correction and occlusion were stable one year after debonding.

Conclusion: The present case indicated that the timely extraction of palatally-placed maxillary lateral incisors facilitated functional appliance therapy in the management of a skeletal Class II problem. The crowding of the lower anterior teeth was relieved and alignment of the upper arch was achieved with full fixed appliance therapy, resulting in improved aesthetics and a stable occlusion at one year review.

The most common cause of dental crowding is the presence of an arch-length--tooth-size discrepancy. Conventional methods of gaining space in orthodontics involve the extraction of teeth, often premolars. However, there are a number of clinical situations in which the extraction of permanent molars might be considered. This paper highlights the indications, advantages, disadvantages and timing of the extraction of the first, second and third permanent molars in the treatment of a crowded malocclusion.

This study applies recent advances in 3D virtual imaging for application in the prediction planning of dentofacial deformities. Stereo-photogrammetry has been used to create virtual and physical models, which are creatively combined in planning the surgical correction of anterior open bite. The application of these novel methods is demonstrated through the surgical correction of a case.

Introduction: The present study involved an assessment of the effects of the Herbst appliance used for Class II correction in subjects with different vertical facial patterns.

Methods: Pre- and post-treatment lateral cephalograms of 91 growing Class II patients were divided into three vertical facial groups on the basis of mandibular plane angulation. All received a Herbst appliance and dental and skeletal changes were assessed in relation to pretreatment incisal overbite, overjet and the stage of cervical maturity.

Results: Herbst appliance treatment was accompanied by changes in the angulation of the upper and lower incisors, overjet reduction and an increase in mandibular length. In general, the rotational facial changes occurring during treatment were minimal, so that dolichofacial patterns remained long and brachyfacial patterns remained short.

Conclusion: Herbst appliance treatment can be expected to result in considerable Class II dental correction. It is unlikely, however, that its use will be associated with clinically significant forward rotation in dolichofacial subjects. Since dolichofacial patterns are likely to remain long-faced, even after considerable Class II dental correction, orthognathic surgery may still be a consideration if normal facial proportions, without excessive facial convexity and lip strain, are treatment aims.

Objectives: To evaluate the antibacterial properties and effects of an orthodontic adhesive containing copper nanoparticles (NPs) on the material's shear bond strength.

Methods: Antimicrobial activity was analysed by a disk diffusion test against S. aureus, E. coli and S. mutans. The NPs were added to the orthodontic adhesive at 0.0100 wt%, 0.0075 wt%, and 0.0050 wt%. Sixty extracted bicuspids were divided into two groups and the enamel of all teeth was conditioned with phosphoric acid. A coat of moisture insensitive primer (MIP) was applied prior to the bonding of brackets with composite resin. Group I served as a control and the bonding procedure was performed according to the manufacturer's instructions. Group II comprised the test teeth, into which 0.0100 wt% copper NPs were included in the MIP. Samples were tested and statistically analysed (p ≤ 0.05). The adhesive remnant index (ARI) was also assessed microscopically. -

Results: The adhesive with copper NPs showed a bactericidal effect against the bacteria under study. A significantly higher bond strength was obtained with the orthodontic adhesive that included 0.0100 wt% of copper NPs (15.23 ± 6.8 MPa) in comparison with the control group (9.59 ± 4.3 MPa). The ARI scores indicated that the groups were significantly different and strengthened by the incorporation of NPs (p = 0.004).

Conclusion: The results of the present study suggested that an orthodontic adhesive, which included copper NPs, significantly increased material shear bond strength without adverse side effects on colour and appearance. The adhesive interface was strengthened by homogeneously dispersed copper NPs added as a nanofiller.

Aim: The present study examined the effect of topical fluoride treatment on the shear bond strength (SBS) of orthodontic brackets using single-dose fluoride varnishes and assessed according to different post-application times and the pattern of debond.

Methods: Of the 105 extracted human mandibular premolars used in the study, 70 were subjected to the SBS test and the remaining 35 to the Adhesive Remnant Index (ARI) test. The teeth were divided into a control group and six test groups: Kolorz ClearShield 5% NaFl varnish Day 1, 8, and 15; and Vanish 5% NaFl varnish Day 1, 8, and 15. The samples were coated with their respective varnish, following which, brackets were bonded. Each specimen was subjected to a shear force in a universal testing machine until failure. Data were analysed using the analysis of variance (ANOVA).

Results: At all time intervals, the mean SBS of the Vanish groups was not significantly different from the control group, and the shear strength in the ClearShield groups was significantly higher than the control and Vanish groups, except at Day 8 (no difference). For the same bonding material, there was no significant difference in mean SBS over different time intervals. ARI scores showed no significant difference between the groups.

Conclusion: The application of single-dose fluoride varnish, irrespective of the length of time between the fluoride treatment and bonding procedure, does not negatively affect the shear bond strength of orthodontic brackets.

Background: Combined orthognathic-orthodontic treatment can be lengthy and expensive. It is therefore important to evaluate the effectiveness of proposed treatment and the likely outcomes.

Objectives: To determine the demographic and surgical details of patients who received orthognathic-orthodontic treatment at Christchurch Hospital, New Zealand, and to assess treatment using the Severity and Outcome Index (SOI).

Methods: An observational and retrospective study was conducted of patients who received surgical orthodontic treatment between 2005 and 2012 at Christchurch Hospital. Pre- and post-treatment lateral cephalometric radiographs of 93 patients were evaluated. Seven cephalometric parameters were assessed using the Severity and Outcome Index. A severity score ranged from 0 for the most severe to 7 for the least severe, while the outcome score ranged from 0 for the worst to 7 for the best outcome.

Results: Class II patients had a severity score of 3.4 and the best outcome score of 6.2. Class III patients had a severity score of 3.3 and an outcome score of 6.1. Patients with an anterior open bite (AOB) had the worst severity score of 3.0, and the worst outcome score of 5.9. The overall treatment outcome scores for all groups were statistically significantly greater than the severity scores, which increased from 3.4 to 6.1 (p < 0.05).

Conclusions: Favourable outcomes were achieved for a group of patients with a high need for treatment. Christchurch Hospital appeared to be treating cases of increased severity and gained better treatment outcomes when compared with a United Kingdom (UK) national audit.