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Introduction The aim of this study was to evaluate the short- and long-term effects of hybrid-Hyrax, Alt-RAMEC and applied, miniscrew reinforced, heavy intermaxillary elastics on a modified lingual arch in growing skeletal Class III patients. Methods Fifteen subjects (seven male, eight female) were included, with an average age of 12.52 ± 0.94 years, of cervical vertebrae maturation (CVM) stage CS2-CS4 and skeletal Class III malocclusions due to a retrognathic maxilla. Nine weeks of Alt-RAMEC were followed by eight to nine weeks of maxillary protraction with heavy 400 gm Class III elastics worn 24 h/day. Treatment was finalised with orthodontic fixed appliances. Cone beam computed tomographic (CBCT) scans were taken initially (T1), at the end of maxillary protraction (T2) and four years after active orthopaedic treatment (T3). Cephalometric measurements were performed on reconstructed lateral cephalograms and the differences between time intervals were calculated using an analysis of variance (ANOVA). Results A positive overjet was achieved in all but one subject. From T1 to T2, A point advanced 3.12 ± 3.42 mm and from T2 to T3 advanced a further 2.21 ± 3.49 mm. Significant initial increases in SNA of 1.05° ± 1.10° (p = 0.004), ANB of 2.71° ± 1.01° (p = 0.00), Wits of 4.49 ± 2.21 mm (p = 0.00) and overjet of 4.90 ± 1.66 mm (p = 0.00) were accomplished and maintained without significant changes in the vertical dimension. Upper and lower incisor inclinations were not affected by the protraction protocol but significantly increased (U1-PP: 8.39° ± 5.59°) between T2 and T3. SNB decreased initially by 1.67° ± 1.34° (p = 0.00) but relapsed due to residual mandibular growth and a counterclockwise rotation of the mandibular plane. Conclusion The hybrid-Hyrax Alt-RAMEC combined with miniscrew reinforced heavy Class III elastics resulted in a favourable and stable Class III correction.

Introduction Anchorage is crucial in controlling tooth movement during orthodontic treatment. Different designs have been introduced to increase the stability of miniscrews. A new miniscrew, The Sydney Mini Screw (SMS), with a hollow chamber and lateral port holes, has been developed to allow the diffusion of an injectable bone graft substitute (iBGS) into cancellous bone. The aim of this study was to analyse the optimum iBGS application with ideal chemo-mechanical properties to be used in conjunction with the novel SMS. Method A composite calcium sulphate and calcium phosphate bone graft substitute was examined. The effects of powder particle size, and the powder-to-liquid ratio on the injectability of the iBGS through the SMS were investigated. The viscosity, injectability, and mechanical properties of the new composite mixtures were assessed using rheology and universal compression measurements. Results The results showed that the optimised injectable formulation of the bone cement was acquired with the concentration of 2.5 g/ml. This concentration was readily injectable through the SMS, and its setting time was within 2–3 minutes, which is favourable for clinicians. In addition, the resulting structure fractured at 80 kPa compression stress. Conclusion The result of this study identified the specific particle size and powder-to-liquid ratio of the iBGS that can be used in conjunction with the new SMS to enhance the primary stability of orthodontic miniscrew applications.

Background With minimal manufacturer information, a variety of ‘generic’ orthodontic brackets are available online from overseas distributors. The present study investigated the metal composition of generic orthodontic brackets compared with two well-known ‘proprietary’ brands. Materials and methods Ranging in price from AU$2.99 to $65, five sets of different generic brackets were obtained directly from China via eBay (G1, G2…G5). Proprietary brackets were obtained from American Orthodontics (P1) and Rocky Mountain Orthodontics (P2). The 11, 12, 13 and 14 brackets from each set were liquefied in an acid solution and subjected to trace element analysis using inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectroscopy (ICP-OES) with respect to nickel, chromium, iron, copper, molybdenum, manganese, cadmium, mercury, arsenic and lead. Statistical analysis investigated the compositional consistency within and between each brand. Results The composition of P1 and P2 agreed with the manufacturer’s data. The generic groups typically had low molybdenum and higher copper content and approximated either 17-4 or AISI304 stainless steels or a combination of both. No relationship between brand and consistency of manufacture could be identified. The cheapest bracket contained lead. Conclusions Generic and proprietary brackets showed differences in their metal composition that may have biocompatibility implications.

Background 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). Materials and methods 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). Results 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. Conclusions 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.

Objectives 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. Materials and methods 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. Results 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. Conclusion 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.