rss_2.0Australasian Orthodontic Journal FeedSciendo RSS Feed for Australasian Orthodontic Journal Orthodontic Journal Feed aligner therapy procedures and protocols of orthodontists in New Zealand<abstract> <title style='display:none'>Abstract</title> <sec> <title style='display:none'>Objective</title> <p>To survey clear aligner therapy (CAT) procedures and protocols of orthodontists in New Zealand.</p> </sec> <sec> <title style='display:none'>Methods</title> <p>One hundred and ten full members of the New Zealand Association of Orthodontists were invited to complete an e-survey. The questions related to respondent demographics, aligner choice and use, CAT planning and treatment protocols, case selection, patient-reported CAT problems and relevant respondent opinions. The reasons for respondents not providing CAT were also surveyed.</p> </sec> <sec> <title style='display:none'>Results</title> <p>The response rate was 70%. Most respondents (88.3%; <italic>N</italic> = 68) reported that they used CAT as a treatment modality with 43.15% (<italic>N</italic> = 29) treating between 1 and 20 patients per year. The predominant CAT system was the Invisalign appliance (70.3%; <italic>N</italic> = 45) with 49.2% (<italic>N</italic> = 32) stating that they used more than one CAT system. The respondents reported the areas which were always or mostly in need of amendment prior to acceptance of the CAT treatment plan were attachments (75.6%; <italic>N</italic> = 50) and final tooth positions (62.1%; <italic>N</italic> = 41). A median of 0% (IQR: 0, 1) of initial digital treatment plans were approved without changes according to the respondents with a median of 90% (IQR: 80, 99) of CAT patients requiring an additional aligner phase. Almost 80% (78.1%; <italic>N</italic> = 50) indicated that they were not comfortable in treating cases with increased overbite and 66.7% (<italic>N</italic> = 44) rarely or never carried out premolar extractions when using CAT. A remote monitoring system was mostly or always used by 32.4% (<italic>N</italic> = 21) of respondents in conjunction with CAT. Concern regarding patient compliance with CAT protocols was expressed by 43.5% (<italic>N</italic> = 22). That fixed appliances provided better treatment outcomes was a moderate or major influence on the decision of all respondents (<italic>N</italic> = 8) who did not provide CAT.</p> </sec> <sec> <title style='display:none'>Conclusion</title> <p>Although CAT provision by orthodontists is commonplace among orthodontists in New Zealand, there is wide variation in its usage and procedures.</p> </sec> </abstract>ARTICLEtrue workflows for 3D-printed customised double-slotted lingual appliances: a case report<abstract> <title style='display:none'>Abstract</title> <p>With the advancement of three-dimensional (3D) printing technology, orthodontists are able to design and manufacture customised lingual appliances, which may increase treatment versatility and reduce treatment costs. The present article describes the digital workflows associated with the design and manufacture of customised double-slotted lingual brackets and arch wires. Also demonstrated is the technique’s efficiency through a non-extraction case report. An adult patient with moderate crowding in both arches was successfully treated using 3D-printed customised double-slotted lingual appliances combined with miniscrews and interproximal reduction. The moderate crowding was addressed without incisor proclination despite the non-extraction strategy.</p> </abstract>ARTICLEtrue using braided bonded wires: a 2-year follow-up of the dentition and oral hygiene with predictors of relapse<abstract> <title style='display:none'>Abstract</title> <sec> <title style='display:none'>Objective</title> <p>To assess gingival health and predictors of relapse related to braided-wire bonded retainers after the active phase of comprehensive orthodontic treatment.</p> </sec> <sec> <title style='display:none'>Materials and methods</title> <p>Fifty-one subjects were recruited in a prospective study of whom 42 were available for analysis after 2 years of retention (pre-therapeutic ages 11–18 years; 66% female). A rectangular wire retainer (0.027 × 0.011″) was bonded to the mandibular incisors. Little’s index of incisor irregularity; intercanine width; the accumulation of biofilm, calculus and gingivitis; and the incidence of retainer detachment, were recorded. Subjects were examined before orthodontic therapy, upon therapy completion, and after 2 years of retention.</p> </sec> <sec> <title style='display:none'>Results</title> <p>The incidence of retainer detachment over the 2 years was 27%. The post-treatment incidence of irregularity was 17%, and intercanine width reduction was 24%. Calculus accumulation increased significantly during retention (<italic>p</italic> &lt; 0.001) but not the extent of gingivitis. A multiple logistic regression demonstrated that an increase of mandibular intercanine width by ≥3 mm correspondingly increased the odds of relapse 14.3 times (95% confidence interval [CI], 1.1–196.1; <italic>p</italic> = 0.046). Patients presenting with retainer failure were 10 times (95% CI 1.6–62.8; <italic>p</italic> = 0.014) more likely to experience relapse. Subjects who experienced relapse had retainer failure earlier than those without relapse (19 vs. 23 months; <italic>p</italic> = 0.003). The occurence of relapse was not related to a treatment change in incisor irregularity, the duration of treatment, the age of the patient, gender nor to a change of intercanine width during retention.</p> </sec> <sec> <title style='display:none'>Conclusion</title> <p>Post-treatment changes in the mandibular arch incorporating bonded retainers were not large, but were common. An increase in mandibular incisor irregularity during retention is mostly related to treatment-induced intercanine width expansion. The bonded retainer often detached and increased calculus accumulation.</p> </sec> </abstract>ARTICLEtrue of a severe skeletal Class II malocclusion through growth modification: a problem-oriented case report<abstract> <title style='display:none'>Abstract</title> <p>A skeletal Class II malocclusion is an anteroposterior discrepancy resulting from a combination of skeletal and dental factors. In adolescent patients, it is possible to leverage their growth potential to address bone deformities and minimise the need for future surgical interventions. In the present case report, a combination treatment approach was adopted which included a functional appliance, fixed appliances, and temporary anchorage support, to treat a 13-year-old Chinese male with a severe skeletal Class II malocclusion. After a treatment duration of 36 months, the patient achieved a favourable occlusion and an improved facial profile. Subsequently, a stable occlusal relationship and balanced facial proportions were maintained during a 2-year retention period.</p> </abstract>ARTICLEtrue in pharyngeal airway space and hyoid bone position after Bionator treatment of skeletal Class II malocclusions<abstract> <title style='display:none'>Abstract</title> <sec> <title style='display:none'>Objectives</title> <p>The objective of this study was to investigate the treatment effectiveness of long-term Bionator use on the craniofacial pattern, nasopharynx, oropharynx, hypopharynx, hyoid bone, and cervical vertebrae in patients presenting with a skeletal Class II malocclusion involving mandibular retrognathia.</p> </sec> <sec> <title style='display:none'>Methods</title> <p>A treatment group of 27 patients with a skeletal Class II malocclusion treated using a Bionator was compared with a control group of 27 patients presenting with a skeletal Class I malocclusion managed without Bionator treatment. The Bionator was worn in the subject group until the complete eruption of the second molars. Lateral cephalograms of the group before (T0) and after Bionator treatment (T1) were compared. A two-way analysis of variance and a paired <italic>t</italic>-test were applied for statistical analyses.</p> </sec> <sec> <title style='display:none'>Results</title> <p>A significant increase in the SNB angle and a decrease in the ANB angle were apparent in the Bionator treatment group. The dimensions of the oropharyngeal and hypopharyngeal airways and the hypopharyngeal area increased significantly. <italic>Conclusion</italic> Long-term treatment using a Bionator resulted in the advancement of a retrognathic mandible. In addition, the dimensions of the oropharyngeal and hypopharyngeal airways and the hypopharyngeal area increased significantly, reaching the same level as that of skeletal Class I subjects.</p> </sec> </abstract>ARTICLEtrue of infrazygomatic crest bone screw position using a postero-anterior cephalogram versus cone-beam computed tomography: a cross sectional study<abstract> <title style='display:none'>Abstract</title> <sec> <title style='display:none'>Background</title> <p>The position of infrazygomatic crest bone screws is an important consideration in determining the success of orthodontic treatment. The aim of this study was to compare the position of infrazygomatic crest (IZC) bone screws in relation to skeletal and dental parameters using postero-anterior (PA) cephalograms and cone beam computed tomography (CBCT).</p> </sec> <sec> <title style='display:none'>Methods</title> <p>A CBCT scan and a PA cephalogram were taken of 19 patients (8 males; 11 females) after IZC bone screw placement. Each CBCT image was reconstructed and oriented using the CS 3D CBCT software (Carestream Dental LLC, Atlanta, USA) and was subsequently analysed. The landmarks were traced on the PA cephalogram. The angulation of the IZC bone screw was measured with respect to three skeletal and two dental landmarks and compared between the two imaging modalities. A paired <italic>t</italic>-test was applied to compare the means of different variables between the PA cephalogram and CBCT scan.</p> </sec> <sec> <title style='display:none'>Results</title> <p>The results showed no statistically significant difference between the two imaging modalities with respect to four landmarks, i.e., the inter-jugale plane, the mid sagittal plane, the zygomatic arch and the perpendicular long axis to the 1st molar but a small statistically significant difference was seen with respect to measurements from the facial surface of the 1st molar (<italic>P</italic> ≤ 0.05).</p> </sec> <sec> <title style='display:none'>Conclusion</title> <p>The angulation and position of an IZC bone screw are consistent between the two imaging modalities. A PA cephalogram may be used as a substitute for a CBCT scan to reduce the radiation exposure to patients.</p> </sec> </abstract>ARTICLEtrue cartilage calcification during development contributes to the formation of irregular articular surfaces as revealed by micro-CT images<abstract> <title style='display:none'>Abstract</title> <sec> <title style='display:none'>Introduction</title> <p>The histological features of irregular mandibular condylar surfaces revealed on CT images remain unknown.</p> </sec> <sec> <title style='display:none'>Aim</title> <p>In order to seek clarification, the aim of the study was to describe the histological features of irregular mandibular condylar surfaces detected on micro-CT images.</p> </sec> <sec> <title style='display:none'>Materials and methods</title> <p>Due to different modelling requirements, thirty rats were exposed to five experimental occlusal disturbance models at 6- or 8-weeks of age. Another six age-matched rats were used as controls. After 10 or 12 weeks of modelling, the mandibular condyles were sampled for micro-CT scanning and histology, immunohistochemistry and immunofluorescence assessment. The condyles with irregular surface signs were chosen for analysis.</p> </sec> <sec> <title style='display:none'>Results</title> <p>Based on the micro-CT images, 10 out of the 30 condyles were diagnosed as having irregular articular surfaces which typically appeared as lacunae on histological sections. The lacunae were filled with degraded cartilage, a fibrous mass, or calcified islets. Type II collagen-, type X collagen- and osterix-positive cells were observed at the side walls of the lacunae. Cleaved caspase-3-positive cells, CD90-positive cells and fibronectin-positive areas were observed inside the lacunae. However, in the subchondral bone at the lower margin of the lacunae, TRAP-positive cells were seldom observed.</p> </sec> <sec> <title style='display:none'>Conclusions</title> <p>Irregular mandibular condylar surfaces revealed by micro-CT images during development appeared to be a result of unbalanced cartilage calcification.</p> </sec> </abstract>ARTICLEtrue years of clear aligner therapy: a bibliometric analysis (2002-2022)<abstract> <title style='display:none'>Abstract</title> <sec> <title style='display:none'>Introduction</title> <p>Clear aligner (CA) therapy has become popular worldwide but there is little research in the area from the perspective of bibliometrics. The present study aimed to identify the most impactful studies on CA over its 20 years of publishing since 2002.</p> </sec> <sec> <title style='display:none'>Methods</title> <p>The Web of Science database was used to retrieve study records on CA for the period between 2002 and 2022. Two authors manually screened the related studies. CiteSpace was used to analyse the country and institutional co-operation, keywords and citations with the strongest ‘burst’.</p> </sec> <sec> <title style='display:none'>Results</title> <p>The number of CA publications has increased and a total of 613 studies were included in the current analysis. The <italic>American Journal of Orthodontics and Dentofacial Orthopedics</italic> was the leading publishing journal reporting 79 published CA articles and 1627 total citations. Italy had the most significant productivity in this field (142/613, 23.16%). The United States of America was the leading country with the highest international collaboration. Based on the results of keyword analysis, orthodontic treatment, digital orthodontics, superimposition, and apical root resorption were previous research emphases.</p> </sec> <sec> <title style='display:none'>Conclusions</title> <p>The present analysis indicates that the treatment outcomes of CA therapy is the focus of current studies and provides developments for future research. The results provide an increased and comprehensive understanding of the state of the art of CA treatment.</p> </sec> </abstract>ARTICLEtrue comparison of bond strength and adhesive remnant index of 3D-printed and metal orthodontic brackets attached using different adhesives<abstract> <title style='display:none'>Abstract</title> <sec> <title style='display:none'>Introduction</title> <p>The aim of this in vitro study was to evaluate the shear bond strength (SBS) and adhesive remnant index (ARI) scores of two different adhesive applications of aesthetic brackets produced from permanent crown material using 3D-printing technology.</p> </sec> <sec> <title style='display:none'>Methods</title> <p>Sixty maxillary premolar teeth extracted for orthodontic reasons were divided into two main groups according to the type of bracket (metal brackets <italic>n</italic>=30, 3D-printed brackets <italic>n</italic>=30) and further divided into two subgroups according to the type of adhesive (flowable composite, Tokuyama SuperLow; non-flowable composite; 3M Transbond XT). SBS and ARI score evaluations were conducted in the experimental and control subgroups (<italic>n</italic>=15). Statistical analysis was performed by a one-way analysis of variance, a post-hoc test, and Fisher’s exact test. Statistical significance was accepted as <italic>P</italic> &lt; 0.05.</p> </sec> <sec> <title style='display:none'>Results</title> <p>The bond strength of the specimens was significantly affected by the type of composite and bracket type (<italic>P</italic> &lt; 0.001). However, the SBS values were within or above the desired range for orthodontic treatment in all groups. The highest SBS value was obtained in the Metal Bracket-Transbond XT group (15.03 ± 6.66), while the lowest SBS value was observed in the 3D-Printed Bracket-Transbond XT group (7.91 ± 3.07). It was noted that of all materials evaluated, the most common non-enamel-damaging adhesive–cohesive fractures were in 3D-Printed Bracket Tokuyama SuperLow group (<italic>n</italic>=13).</p> </sec> <sec> <title style='display:none'>Conclusions</title> <p>It is recommended that 3D-printed orthodontic brackets have sufficient and acceptable SBS levels for clinical applications and bonding using non-flowable adhesives to produce high SBS values and using flowable adhesives generating high ARI scores.</p> </sec> </abstract>ARTICLEtrue of the cytotoxicity of 3D-printed aligners using different post-curing procedures: an in vitro study<abstract> <title style='display:none'>Abstract</title> <sec> <title style='display:none'>Objective</title> <p>Three-dimensional (3D) printing technology represents a novel method for manufacturing aligners. The aim of the present study was to assess the in-vitro cytotoxicity of 3D-printed aligners using different post-polymerisation conditions.</p> </sec> <sec> <title style='display:none'>Materials</title> <p>Aligners were printed using the same 3D-print resin (TC-85DAC, Graphy, Seoul, Korea) and printer (AccuFab-L4D, Shining 3D Tech. Co., Hangzhou, China), followed by different post-curing procedures. Six aligners were post-polymerised for 14 min using the Tera Harz Cure and a nitrogen generator curing machine (THC2, Graphy, Seoul, Korea) (P1). A further six aligners were post-cured for 30 min on each side using the Form Cure machine (FormLabs Inc, Somerville, USA) (P2). The aligners were cut into smaller specimens (2 mm×2 mm) and sterilised at 121°C. The specimens were placed in 96-well plates containing Dulbecco’s Modified Eagle’s Medium (DMEM) at 37° for 7 or 14 days. The viability of MC3T3E-1 pre-osteoblasts cultured with DMEM was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The optical density of each cell culture was measured to assess cell viability, following which the data were statistically analysed using two-way and one-way ANOVA (α = 0.05).</p> </sec> <sec> <title style='display:none'>Results</title> <p>The comparison of cytotoxicity revealed statistically significant differences between post-curing procedures and MTT timings (<italic>P</italic> &lt; 0.001). After 7 and 14 days, the cell viability of P2 was significantly reduced compared to P1 and the control groups (<italic>P</italic> &lt; 0.001), while P1 showed no significant differences compared to the controls. Overall, P2 post-curing exhibited moderate cytotoxicity, while P1 post-polymerisation was highly biocompatible.</p> </sec> <sec> <title style='display:none'>Conclusions</title> <p>Different post-curing procedures may affect the in-vitro cytotoxicity of 3D-printed aligners. Clinicians should adhere to the manufacturer’s recommendations when using 3D-print resin.</p> </sec> </abstract>ARTICLEtrue mandibular canine(s) impaction: expansion of our understanding<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction:</italic> Eruption disturbances, tooth size and specific malocclusions are known to be genetically influenced. The clinical association between these traits may indicate common genetic controls.</p> <p><italic>Objectives:</italic> A cross-sectional clinical study was designed to test the null hypothesis that the maximum mesiodistal crown diameter (MMD) of maxillary and mandibular central and lateral incisors and the prevalence of various classes of incisor relationships (Class I, II/1, II/2 and III) do not differ between the subjects with and without permanent mandibular canine(s) impaction.</p> <p><italic>Methods:</italic> Dental models of 43 subjects diagnosed with mandibular canine(s) impaction (Impaction Group - IG) were compared with those of 86 subjects of a control reference sample (Control Group - CG). Independent <italic>t</italic>-test and chi-square tests were used to determine the association between mandibular canine(s) impaction and the MMD of the incisors and the incisor relationship, respectively. The likelihood of various incisor relationships between the IG and CG were evaluated according to odds ratios.</p> <p><italic>Results:</italic> A fourfold increase (<italic>p</italic> &lt; 0.0001) in the overall frequency of Class II/2 incisor relationship was observed in the IG when compared to controls.</p> <p><italic>Conclusions:</italic> The null hypothesis was rejected. Subjects with mandibular canine(s) impaction appeared to be characterised with wider incisors and a remarkably high rate of Class II/2 malocclusion. This information assists the understanding of genetically controlled dental anomalies, which are likely to co-exist with mandibular canine(s) impaction.</p> </abstract>ARTICLEtrue related to stability following the surgical correction of skeletal open bite<abstract> <title style='display:none'>Abstract</title> <p><italic>Objectives:</italic> If a skeletal anterior open bite malocclusion is treated by orthognathic surgery directed only at the mandible, the lower jaw is repositioned upward in a counter-clockwise rotation. However, this procedure has a high risk of relapse. In the present study, the key factors associated with post-surgical stability of corrected skeletal anterior open bite malocclusions were investigated.</p> <p><italic>Material and methods:</italic> Eighteen orthognathic patients were subjected to cephalometric analysis to assess the dental and skeletal changes following mandibular surgery for the correction of an anterior open bite. The patients were divided into two groups, determined by an increase or decrease in nasion-menton (N-Me) distance as a consequence of surgery. Changes in overbite, the displacements of molars and positional changes in Menton were evaluated immediately before and after surgery and after a minimum of one year post-operatively.</p> <p><italic>Results:</italic> The group with a decreased N-Me distance exhibited a significantly greater backward positioning of the mandible. The group with an increased N-Me distance experienced significantly greater dentoalveolar extrusion of the lower molars.</p> <p><italic>Conclusions:</italic> A sufficient mandibular backward repositioning is an effective technique in the prevention of open bite relapse. In addition, it is important not to induce molar extrusion during post-surgical orthodontic treatment to preserve stability of the surgical open bite correction.</p> </abstract>ARTICLEtrue results of surgically-assisted maxillary protraction<abstract> <title style='display:none'>Abstract</title> <p><italic>Objective:</italic> The long-term treatment results of surgically-assisted facemask therapy were assessed by a comparison of the immediate protraction effects with those seen at five years review.</p> <p><italic>Materials and methods:</italic> Nine patients treated with a corticotomy-assisted maxillary protraction protocol were recalled five years following protraction. Cephalometric films taken before treatment (T0), immediately after maxillary protraction (T1) and five years after treatment (T2) were compared.</p> <p><italic>Results:</italic> The short-term results of surgically-assisted facemask therapy showed significant skeletal and soft tissue changes. After five years, the profile and dental relationships were well maintained and a cephalometric analysis revealed a stable vertical increase but only partially maintained soft tissue changes with loss of sagittal advancement. There was significant upper incisor proclination providing dental camouflage.</p> <p><italic>Conclusion:</italic> Patients who are treated with corticotomy-assisted maxillary advancement should be very carefully selected. Assessment criteria include a low mandibular plane angle Class III patients who have severe maxillary retrognathism unable to be treated by conventional orthopaedic correction alone; patients who have almost completed growth and missed the chance of earlier orthopaedic correction, as well as patients who are not willing to accept bimaxillary orthognathic surgery, may be successfully treated.</p> </abstract>ARTICLEtrue and β-adrenoceptor-agonist administration on craniofacial bone density<abstract> <title style='display:none'>Abstract</title> <p><italic>Objective:</italic> β<sub>2</sub>-agonist medications are thought to have adverse effects on bone density. Surgical denervation and intramuscular β<sub>2</sub>-agonist injections appear to have opposing effects on skeletal muscles. The present study has been designed to assess the effects of denervation of the masseter, intramuscular injection of a β<sub>2</sub>-agonist and the combination of both procedures, on bone density in the craniofacial skeleton in rats.</p> <p><italic>Materials and methods:</italic> Sprague-Dawley rats were prepared as four groups: 1. surgical sham + saline injection into the masseter (<italic>sham</italic>); 2. surgical denervation of the masseter (<italic>den</italic>.); 3. surgical denervation of the masseter + intramuscular formoterol injection into the affected muscle (<italic>den.+form</italic>.); 4. intramuscular formoterol injection into the masseter (<italic>form</italic>.). All specimens were submitted for CT examination and volumetric calculations of the mineralised bone tissue were performed.</p> <p><italic>Results:</italic> The sham and form. groups had a greater volume of mineralised bone in the zygoma on the experimental side compared with the control side. The maxilla on the experimental side had a higher volume of mineralised bone in the <italic>den.+form</italic>. and <italic>form</italic>. groups compared with the <italic>sham</italic> and <italic>den</italic>. groups. The control side of the maxilla had a higher volume of mineralised bone in the <italic>den</italic>.+<italic>form</italic>. and <italic>form</italic>. groups compared with the <italic>den</italic>. group only.</p> <p><italic>Conclusion:</italic> Intramuscular administration of formoterol appears to induce a bilateral increase in bone mineral density in the maxilla and the zygoma, likely explained as a secondary effect of the well-described increase in muscle mass and strength associated with β<sub>2</sub>-agonist administration.</p> </abstract>ARTICLEtrue assessment of late fixed functional treatment and the stability of Forsus appliance effects<abstract> <title style='display:none'>Abstract</title> <p><italic>Objective:</italic> To evaluate the treatment effects and stability of Forsus appliance therapy.</p> <p><italic>Methods:</italic> Thirty-one patients (15 males, 16 females) with a mean age of 15.8 ± 3.1 years (range 13 to 17.6 years, 15.3 ± 1.2 years for females and 16.5 ± 1.6 years for males) were selected. All patients had passed beyond their pubertal growth phase (after CS4 or MP3cap). Lateral cephalograms and three-dimensional (3D) models were analysed before treatment (T0), at the end of treatment (T1) and at a follow-up visit (T2). The mean period from T1 to T2 was 25 months and ranged from 17 to 32 months. Tooth position and angulations, together with maxillary and mandibular position, were measured on cephalograms. The inclinations and vertical distance changes of mandibular incisors were measured on a 3D digital model.</p> <p><italic>Results:</italic> The Forsus appliance produced significant skeletal and dental changes during treatment (from T0 to T1). In the sagittal plane, mandibular length (Co-Gn) increased 6.47 mm, the maxillary incisors and molars uprighted (∠U1-SN decreased 8.97° and ∠U6-SN decreased 3.51°), the mandibular incisors proclined (∠L1-MP increased 3.93°) and the mandibular molars advanced (L6-SP increased 3.61 mm). In the vertical plane, the maxilla and mandible rotated clockwise (∠PP-SN, ∠MP-SN, ∠OP-SN increased significantly) and the mandibular molars extruded (L6-MP increased 3.06 mm). All of the changes remained relatively stable after treatment. Cephalometric sagittal and vertical changes affecting the mandibular incisors from T1 to T2 were statistically insignificant (<italic>p</italic> &gt; 0.05) except for lower incisor extrusion (L1-MP, <italic>p</italic> &lt; 0.05).</p> <p><italic>Conclusion:</italic> The Forsus appliance induced significant skeletal and dental changes, which remained relatively stable during the observation period. The mandibular incisors, in particular, were stable two years after treatment.</p> </abstract>ARTICLEtrue evaluation of condylar and ramal vertical asymmetry in adolescents with unilateral and bilateral posterior crossbite using cone beam computed tomography (CBCT)<abstract> <title style='display:none'>Abstract</title> <p><italic>Aims:</italic> The primary purpose was to evaluate condylar and ramal vertical asymmetry in adolescent patients displaying unilateral posterior (UCB) and bilateral posterior crossbite (BCB) malocclusions. A secondary aim was to compare the findings with a matched control group exhibiting normal occlusion (CG) using cone beam computed tomography (CBCT).</p> <p><italic>Material and methods:</italic> The study groups consisted of (1) 30 patients (Mean age: 14.49 ± 1.91years) with a UCB, (2) 29 patients (Mean age: 14.57 ± 1.84 years) with a BCB, and (3) 36 patients (Mean age: 14.24 ± 2.42 years) as a matched control group (CG). Condylar, ramal, condylar-plus-ramal height and index measurements were performed using CBCT images following the method of Habets et al. A paired <italic>t</italic>-test was performed for side comparison in each group. One-way ANOVA (Analysis of Variance) was used to determine statistically-significant differences between the groups for asymmetry index measurements and Tukey’s HSD test was employed for individual group differences.</p> <p><italic>Results:</italic> There was no statistically significant difference in condylar height (CH), ramal height (RH), and condylar plus ramal height (CH + RH) measurements between the right and left sides of the UCB group and CG, except for the RH in the BCB group (<italic>p</italic> = 0.045). Tukey’s HSD test showed that the ramal asymmetry index (RAI) and the condylar plus the ramal asymmetry index (CRAI) were statistically significantly different between the UCB and BCB groups (<italic>p</italic> = 0.035 and <italic>p</italic> = 0.015, respectively).</p> <p><italic>Conclusions:</italic> Although the condylar asymmetry index (CAI) values were found to be high in the groups of UCB (13.84 ± 11.33), BCB (9.38 ± 8.56), and CG (10.58 ± 9.48), the comparisons amongst the groups were not statistically significant. The asymmetry between the UCB and BCB groups was observed for RAI and CRAI values, rather than CAI values.</p> </abstract>ARTICLEtrue effects of a Twin-Force Bite Corrector versus an Activator in comparison with an untreated Class II sample: a preliminary report<abstract> <title style='display:none'>Abstract</title> <p><italic>Objectives:</italic> The present study aimed to compare the treatment outcomes of a fixed-functional appliance (Twin-Force Bite Corrector - TFBC) and a conventional removable functional appliance (Activator) in the treatment of skeletal Class II malocclusions.</p> <p><italic>Methods:</italic> The TFBC and Activator Groups each included 10 young adults possessing a skeletal Class II malocclusion, and the treatment outcomes of both groups were quantified and compared, using lateral cephalometric radiographs, with an untreated skeletal Class II Control Group.</p> <p><italic>Results:</italic> A skeletal Class I relationship and a marked reduction in overjet were achieved in both treatment groups; however, the duration of treatment was significantly shorter in the TFBC Group (0.45 years) when compared with the Activator Group (1.37 years) (<italic>p</italic> &lt; 0.001). Effective length and sagittal positioning of the mandible underwent significant changes in the TFBC and Activator Groups. Vertical facial dimensions increased in each group; however, these increases were significantly greater in the Activator Group when compared to the TFBC and Control Groups (<italic>p</italic> &lt; 0.05). Dentoalveolar changes also contributed to the reduction in overjet.</p> <p><italic>Conclusions:</italic> Although both appliances succeeded in eliminating the Class II relationship and improving the overjet and overbite, the short treatment time in the TFBC Group raises questions regarding the long-term stability of the results.</p> </abstract>ARTICLEtrue bone thickness of the adult alveolar process - a retrospective CBCT study<abstract> <title style='display:none'>Abstract</title> <p><italic>Objectives:</italic> To investigate and compare cortical bone thickness of the posterior alveolar process in adult patients presenting with skeletal Class I, II and III malocclusions.</p> <p><italic>Methods:</italic> Cone beam computed tomographic (CBCT) images of 196 adult subjects, aged 20–45, were evaluated. Cortical bone thickness was measured 4 mm from the alveolar crest, as the shortest bucco-lingual dimension of the cortical bone at interdental sites from the distal of the maxillary canine to the mesial of the maxillary second molar.</p> <p><italic>Results:</italic> There were no differences between the malocclusion groups in mean age, gender, or vertical pattern (<italic>p</italic> &gt; 0.05). At all sites measured, there were no statistically significant differences in the means of cortical bone thickness between the groups (<italic>p</italic> &gt; 0.05). Maxillary palatal bone thickness was reduced in the Class I (<italic>p</italic> &lt; 0.0001), and Class II (<italic>p</italic> &lt; 0.001) groups; but mandibular buccal thickness increased significantly (<italic>p</italic> &lt; 0.001) in all malocclusion groups from anterior to posterior.</p> <p><italic>Conclusions:</italic> There was no difference in cortical bone plate thickness between Class I, II and III subjects when related to mini– implant placement sites. As the measurement site moved towards the posterior, maxillary palatal cortical thickness decreased except in Class III cases, while mandibular buccal bone thickness increased in all malocclusion groups.</p> </abstract>ARTICLEtrue of low-intensity pulsed ultrasound on bone formation after the expansion of the inter-premaxillary suture in rats: a histologic and immunohistochemical study<abstract> <title style='display:none'>Abstract</title> <p><italic>Background:</italic> Orthodontic maxillary expansion is a commonly-performed treatment approach to correct transverse maxillary deficiencies by separating the mid-palatal suture. To obtain a successful treatment result and prevent relapse, the expanded maxillary sutures require maintenance by means of qualified bone reorganisation.</p> <p><italic>Aim:</italic> To assess the effects of low-intensity pulsed ultrasound (LIPUS) on sutural bone formation after the expansion of the inter-premaxillary suture in rats.</p> <p><italic>Methods:</italic> Sixteen male Wistar rats, 6 to 8-week old, were used. The expansion appliance comprised a helical spring fabricated from 0.014 inch stainless steel wire (Dentaurum, Ispringen, Germany). The rats were divided into two equal groups and randomly assigned to the LIPUS treatment group or a sham-operation group. LIPUS was delivered via a 2.5 cm diameter ultrasound transducer (Exogen, Smith and Nephews, Inc., Memphis, TN, USA) for 20 minutes per day during 7 days of post-expansion retention. Following retention, the rats’ maxillae were surgically removed and histologic and immunohistochemical specimens were prepared and examined.</p> <p><italic>Results:</italic> The number of osteoblasts and blood vessel dimensions in the ultrasound group increased but was not significant, compared with the control group. A statistically significant difference in osteocalcin, VEGF and TGF-β immunoreactivities (<italic>p</italic> &lt; 0.01) was found in the area of the mineralising tissue. Only VEGF immunoreactivity was significant between two groups (<italic>p</italic> &lt; 0.01) in the fibrous tissue area.</p> <p><italic>Conclusions:</italic> The area of mineralising tissue in the LIPUS-applied group expressed activity markers for osteocalcin, VEGF and TGF-β compared with a surrounding area of fibrous tissue. Cellular activation in the LIPUS group was greater than that of controls. Therefore, LIPUS may be accepted as a useful approach to enhance sutural bone formation.</p> </abstract>ARTICLEtrue in maxillary molar pulp blood flow during orthodontic intrusion<abstract> <title style='display:none'>Abstract</title> <p><italic>Introduction/Objective:</italic> The aim of this prospective study was to evaluate the effects of maxillary first molar intrusion on pulpal blood flow (PBF) in humans as recorded by laser Doppler flowmetry (LDF).</p> <p><italic>Materials and methods:</italic> Maxillary first molars of 16 participants were divided into two groups. In the study group, 20 teeth in 10 participants were subjected to an intrusive force of 100 g delivered from mini-implants for 6 months. A control group of 6 subjects (12 teeth) received no orthodontic treatment. LDF measurements were recorded at baseline and at 3 days, 3 weeks, 3 months and 6 months during intrusion. Data was analysed using the Wilcoxon Signed Rank and Mann-Whitney U tests, with a level of <italic>p</italic> &lt; 0.05 considered statistically significant.</p> <p><italic>Results:</italic> No significant changes in PBF perfusion units (PU) were observed in the control group over the course of the study. However, PBF in the study group was significantly higher at T0 (8.7 ± 0.9 PU) when compared with T1 (6.1 ± 0.6 PU, <italic>p</italic> &lt; 0.001) and T2 (6.0 ± 0.6 PU, <italic>p</italic> &lt; 0.001). PBF did not vary significantly between T1 and T2 (<italic>p</italic> = 0.073) or between T3 and T4 (<italic>p</italic> = 0.262). Moreover, PBF at the end of the study (T4) was similar to baseline PBF values for both groups (study group: <italic>p</italic> = 0.687; control group: <italic>p</italic> = 0.525).</p> <p><italic>Conclusions:</italic> Despite significant short-term regressive changes in pulpal tissue during continuous molar intrusion with mini-implants and an applied force of 100 g, blood vessel function was maintained throughout intrusion, as indicated by LDF measurements of PBF, which tended to return to baseline values by the end of the observation period. These results highlight the changes that can occur in molar vascularity, especially during six months of intrusion.</p> </abstract>ARTICLEtrue