Volume 34 (2018): Issue 1 (January 2018)

To assess the in vivo colour alterations of two different clear thermoplastic retainers.

Thirty patients were randomly allocated into two Groups (N = 15) following the completion of active orthodontic treatment. Group 1 received Vivera® and Group 2 Essix® C+ thermoplastic retainers. Each patient was provided with two fabricated retainers (one for use and the other to serve as a control). The CIELAB parameters of the patients’ upper central incisors were measured with a SpectroShade™ spectrophotometer immediately after retainer placement (T₀) and again after 15 days (T₁), one month (T₂) and three months (T₃). The measurements were also performed on teeth without the retainer in place. ΔE differences were calculated.

ΔE changes from T₀ to T_p T₂ or T₃ showed no statistically significant differences between Groups 1 and 2 within any combination of measurements or teeth. ΔE_ļŢ3-Ţ0ļ changes for used retainers were 1.55 times higher than control appliances (p = 0.002) and 1.44 times higher than for teeth-only (p = 0.004). For used retainers, changes between T₃ and T₀ were 1.56 times higher than between T and T₀ and 1.47 higher than between T₂ and T₀ (p < 0.001). There were no statistically significant differences in ΔE between teeth 11 and 21.

Used retainers exhibited greater colour change than control appliances or teeth-only readings, and increased commensurate with the duration of use. Vivera® and Essix® retainers exhibited similar colour stability. All differences observed were considered clinically acceptable (ΔE < 3.7), although prolonged use could cause clinically significant colour changes.

The use of Twin Block therapy is a well-accepted functional treatment option for the correction of a Class II malocclusion. In addition to skeletal and dental changes, its use may also promote changes in airway structure and dimension, including the size of the posterior airway space (PAS). This may be of importance in reducing the risk of developing obstructive sleep apnoea syndrome (OSAS).

Sixteen (16) subjects (eight females and eight males) underwent treatment of a Class II division 1 malocclusion via the use of a Sydney Bonded Twin Block (SBTB) appliance followed by full fixed orthodontic therapy (FFOA). Pretreatment (T1), post-twin block (T2) and post-fixed appliance (T3) lateral cephalograms were taken and skeletal and soft tissue landmarks were hand traced. A pairwise comparison was used to assess whether there were any significant differences in the cephalometric variables between each phase of treatment (T1, T2, T3).

The skeletal variables SNB and ANB revealed a significant change between T1-T2 (p < 0.01). The sagittal size of the nasopharynx (RPAS) also recorded a significant change between T1-T3 (p < 0.05). There was no significant change in the PAS at any stage of treatment. There was an average reduction in the ANB angle of 2° (p < 0.01) between T1-T3.

There was no significant change in the size of the PAS following SBTB treatment. However, an increase in RPAS was recorded following SBTB treatment which continued to improve during FFOA therapy.

To evaluate the accuracy of maxilla and mandibular repositioning during two-jaw orthognathic surgery using computerassisted surgical simulation (CASS)

Fifteen patients who underwent two-jaw orthognathic surgery using CASS (VSP,® Orthognathics by 3D Systems) were evaluated to assess the accuracy of the simulation. Translational and rotational discrepancies of the centroids of the maxilla and mandible and the translational discrepancy of the dental midline between the planned and actual outcomes were reported using the root mean square error (RMSE). The number of cases that exceeded limits set for clinical significance, the direction of the error in relation to the direction of planned movement and the differences between segmental and non-segmental procedures were evaluated as secondary outcomes

The largest translational RMSE was 1.53 mm along the y-axis in the maxilla and 1.34 mm along the y-axis in the mandible. The largest rotational RMSE was 1.9° about the x-axis in the maxilla and 1.16° about the x- and y-axes in the mandible. The largest RMSE for the dental midline was 1.6 mm along the y-axis in the maxilla and 1.34 mm along the y-axis in the mandible. A tendency for insufficient advancement of the maxilla was noted

CASS is an efficient and accurate way to develop the surgical plan and transfer the plan to the patient intraoperatively. While CASS is accurate on a population level, there remains the potential for clinically significant errors to occur on an individual basis

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 purpose of this study was to qualitatively and quantitatively analyse the effect of glucosamine sulfate and chondroitin sulfate supplements on condylar remodelling in conjunction with bite-jumping functional appliance therapy in rats.

The study involved 140 three-week-old, female rats which were divided into a control group (CG), a supplementation group (SG), a functional appliance (bite-jumping) group (FG) and a bite-jumping appliance and supplement recipient group (FSG). The animals were sacrificed at Day 0, Day 7 and at Day 21 after appliance placement, as well as seven days following appliance removal. The condylar head from each animal was blindly scanned using micro-computed tomography (μCT). Qualitative evaluation and volumetric measurements of the condyles, including total condylar volume (TCoV), posterior condylar volume (PCoV), total cartilage volume (TCaV) and posterior cartilage volume (PCaV), were undertaken using VGStudioMax software.

One hundred and thirty-five rats were analysed, some of which responded to the intervention with a protruded bite (Class III response) while others responded with a retruded bite (Class II response). The TCoV and PCoV of the CG decreased during the experimental period. The functional appliance alone and the combination of the functional appliance with the supplement had a significant effect on TCoV and PCoV over the intervention period (p < 0.01), peaking at Day 7. There was no statistically significant difference in TCaV between animals that experienced Class II and Class III bite responses at Days 21 and 28 (p > 0.05). However, at Day 21, the PCaV increased significantly in those animals which displayed a Class II bite response (p < 0.05). The shape of the condyles in FG and FSG varied significantly from that of the condyles in CG and SG.

Supplement therapy was found to enhance the normal biological response to functional appliance therapy in a rat model, particularly after the functional appliance was removed. Further research using an immuno-histochemical analysis of a modified bite-jumping appliance and improved food delivery is recommended.

The aim of the present study was to assess sexual dimorphism related to occlusal variables recorded from dental casts of Australian twins and to compare trends across primary (T1), mixed (T2) and permanent (T3) dentitions in the same individuals.

The sample comprised 22 males and 25 females selected at random from monozygotic pairs and 19 males and 19 females from dizygotic pairs. Overjet, overbite, midline deviation, midline diastema, primary and permanent molar relationship, and primary and permanent canine relationships were measured in millimetres using a digital calliper

The mean values for overjet in males in the permanent dentition and for overbite in the mixed and permanent dentitions were significantly greater than those for females. The other occlusal traits showed no sexual dimorphism. Midline diastemata were most prevalent in the primary dentition while coincident midlines were most prevalent at all stages for both genders. In addition, a mesial step deciduous molar relationship was more prevalent on the right side and a flush terminal plane present on the left. Furthermore, a Class II permanent molar relationship was predominant in T1/T2, while a Class I relationship was most prevalent in the permanent dentition. Class II primary and permanent canine relationships were most common at all stages

Significant sexual dimorphism was found for overjet and overbite at several occlusal developmental stages but sexual dimorphism was not found for the other occlusal traits studied

This systematic review aims to determine the most effective method of treatment to remineralise post-orthodontic white spot lesions (WSLs).

Six databases were accessed and searched for articles. Screening and selection were conducted according to the PRISMA guidelines using predetermined inclusion and exclusion criteria. Two reviewers independently assessed and extracted identified studies and relevance disagreement was resolved through consensus. Experimental studies were included that involved (i) patients of any age who had WSLs after the removal of fixed appliances, (ii) any treatment to remineralise the WSLs compared with no treatment or a placebo, and (iii) measurement of the changes in enamel mineralisation status after treatment. Eligible articles were assessed for internal bias and underwent narrative synthesis. A meta-analysis using random-effects modelling was performed to calculate a pooled estimate and assess between-study variability using Cochran’s Q and I².

The nine articles included in this review were found to have a medium or high risk of bias. The qualitative assessment provided contrasting results between studies. The meta-analysis showed both CPP-ACP – pooled d of -0.28 (N = 5 studies; 95% CI = -0.48- -0.07) – and fluoride – pooled d of -0.25 (N = 4 studies; 95% CI = -0.48- -0.02) – to generate improvement in the enamel mineralisation status, with CPP-ACP producing more consistent results compared with fluoride.

The meta-analysis found that CPP-ACP and fluoride were effective in reducing post-orthodontic WSLs. Due to the heterogeneity of the included studies with regard to the fluoride concentrations and mode of delivery, the current meta-analysis could not accurately establish which remineralising agent, CPP-APP or fluoride, is more effective. Further high quality studies of long-term duration are required to determine best clinical practice.

Of the types of dental trauma, intrusive luxation is considered to have the worst prognosis. When forceful intrusion affects multiple adjacent teeth, orthodontic repositioning may be required; however, orthodontic treatment can be complicated by the development of a cant in the occlusal plane, especially when the affected teeth are not symmetrically located from the midline and corrective forces and anchorage are unbalanced. Designing an appropriate mechanism to overcome this problem is essential.

The present case report describes a 28-year-old male who suffered the traumatic intrusion of multiple teeth, with accompanying alveolar bone fractures, following a road traffic accident. The intruded teeth were repositioned using orthodontic traction, following which, endodontic treatment was performed. After initial alignment, differential curve of Spee mechanics were applied to correct the occlusal plane and an acceptable result was achieved. The overall outcome was maintained at a 24-months review.

This report demonstrates the importance of the early repositioning of intruded teeth to avoid dento-alveolar ankylosis, as well as the use of differential curve of Spee mechanics which provides effective force application in the management of a canted occlusal plane.

The orthodontic treatment of patients with idiopathic condylar resorption (ICR) remains controversial. The effect of molar intrusion using temporary anchorage devices (TADs) and the consequential gradual counterclockwise rotation of the mandible in patients with ICR remains unclear.

To present the long-term treatment result of an adult skeletal Class II open-bite malocclusion with a history of ICR corrected by the combination of orthognathic surgery and TADs.

After six months of occlusal splint therapy, a surgically-assisted intrusion of the maxillary molars was performed using TADs, followed by a bilateral sagittal split osteotomy (BSSO) and genioplasty.

The five-year post-treatment records showed a good facial appearance, occlusion and mandibular/condylar position with no progress in the condylar resorption.

Based on a single case, this treatment option is an effective alternative to a bimaxillary osteotomy for patients presenting with ICR.

The present case report describes the orthodontic management of a patient who presented with a skeletal Class III malocclusion combined with other dental anomalies. The malocclusion was complicated by agenic maxillary lateral incisors and a lower right second premolar, in company with the transposition of the maxillary canines and premolars.

Dentoalveolar compensation of the anteroposterior jaw relationship was performed. The upper deciduous lateral incisors were extracted and the spaces closed, so that the first premolars replaced the missing lateral incisors while the canine transposition was maintained

Satisfactory results were obtained which provided an improvement in function and occlusal stability, as well as smile and profile aesthetics.

This case demonstrates the importance of an accurate diagnosis when many treatment options are available and clearly addressed.

A young adolescent female, aged 17 years and one month, presented seeking orthodontic treatment to address the congenital absence of her maxillary lateral incisors.

The therapeutic aims were to provide an adequate aesthetic and functional occlusion, coupled with sound adjunctive periodontal tissue relationships and a favourable long-term prognosis.

The malocclusion was managed by customised lingual orthodontic appliances and the adjunctive use of direct skeletal anchorage derived from two palatal mini-implants.

The treatment objectives of good aesthetics, a functional occlusion, normal function, a healthy periodontium and a balanced profile were readily achieved. The retention records demonstrate the stability of the correction. The treatment duration was approximately 41 months, which encompassed the use of full fixed customised lingual appliances over a period of 24 months.