<abstract><title style='display:none'>Abstract</title>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.</abstract>

The orthodontic extraction of permanent molars: a literature review

Reviews

<abstract>
<title style='display:none'>Abstract</title>
Purpose and methods: The distalisation of molars using clear aligners has been found to be achievable; however, the distalisation of an entire arch is still an orthodontic challenge and reported as only clinically possible using fixed appliances. To date, there has been no study on the distalisation of both dental arches using a clear aligner system. In the present report, a case is described in which the entire maxillary and mandibular arches were successfully distalised using clear aligners and miniscrews for the treatment of a bimaxillary protrusion malocclusion in a 22-year-old female patient. Pre- and post-treatment records as well as 1.5-year follow-up records are presented.
Results: The distalisation of both dental arches was achieved using a V-pattern staging process by moving the second molars, then the first molars, followed by the premolars and the anterior teeth, as well as by elastics applied between precision cutouts in the aligners and the miniscrews. The dental arches were efficiently distalised by approximately 3 millimeters in the first molar areas after 13 months of treatment. A review 1.5 years post-treatment showed that the outcome was stable without significant relapse observed in the facial profile and occlusion.
Conclusion: The distalisation of both dental arches is achievable using clear aligner systems by applying elastics between miniscrews and precision aligner cutouts in the treatment of a bimaxillary protrusion malocclusion.
</abstract>

Distalisation of the dental arches using clear aligners and miniscrews

<abstract><title style='display:none'>Abstract</title>The distinguishing features of Class I, Class II and Class III craniofacial growth have been subjects of orthodontic research since the middle of the 20th century. However, the moral and practical issues related to studying craniofacial growth in modern times have presented unresolved challenges to researchers. While previous longitudinal growth investigations are typically based on historical data sets, the cephalometric growth studies of contemporary populations must now rely on cross-sectional data. Furthermore, clinical orthodontic research has faced similar ethical challenges in which therapeutic outcomes are analysed using historical control data. These limitations, amongst others, have obscured the conclusions that can be drawn from both types of studies. This article begins with a review of the defining characteristics of Class I, Class II and Class III growth and then explores the limitations of growth studies and the use of historical control groups in orthodontic research.</abstract>

Craniofacial growth studies in orthodontic research — lessons, considerations and controversies

<abstract><title style='display:none'>Abstract</title>Interproximal reduction (IPR) is the deliberate removal of part of the dental enamel from the interproximal contact areas, which decreases the mesiodistal width of a tooth. This enamel may be removed for various reasons, but most commonly to create space during orthodontic treatment or to correct tooth-size discrepancies. Several authors have also encouraged its use as a method by which post-orthodontic stability might be enhanced, particularly in the lower anterior region. With the increased use of removable aligners for orthodontic treatment in which non-extraction therapy is often advocated, the use of IPR becomes a valuable tool to relieve crowding without over-expanding the dental arches.It is possible that inaccurate IPR could result in the over-reduction of enamel, the creation of ledges and notches in the proximal surfaces, increased tooth sensitivity or damage to the surrounding soft tissues. However, carefully conducted IPR performed within the recommended guidelines may be used as a safe method to gain space for the relief of crowding, to correct tooth-size discrepancies and to improve aesthetics and long-term stability in selected orthodontic patients.</abstract>

Interproximal reduction in orthodontics: why, where, how much to remove?

<abstract>
<title style='display:none'>Abstract</title>
Introduction: Incisal torque in orthodontics has always been important due to its relationship with smile aesthetics and the stability of a final treatment outcome. The aim of this study was to quantify the accuracy of torque expression predicted by ClinCheck® planning associated with Invisalign® treatment, compared to clinical outcomes.
Methodology: Forty adult patients consecutively treated using the Invisalign appliance were selected. Torque and the interincisal angle (IIA) were measured at T0 (pretreatment), T1 (predicted post-treatment), and R (end of initial aligner sequence) stages on STL files using metrology software (Geomagic Control X).
Results: The difference between the predicted and achieved torque (torque differential) was statistically significant (<italic>P</italic> &lt; 0.001) in the labial crown torque group with a mean of 6.43° (SD = 7.09) for the upper central incisor, 5.06° (SD = 7.32) for the upper lateral incisor and 2.75° (SD = 5.7) for the lower incisor sub-groups. In contrast, the corresponding lingual/palatal crown torque sub-groups did not show a statistically significant torque differential (<italic>P</italic> &gt;0.05). Similar observations were made for the IIA differential (difference between predicted and achieved IIA) with a mean IIA differential of 9° (SD = 10.73; <italic>P &lt;</italic> 0.001) and -3.4° (SD = 7.9; <italic>P</italic> &gt; 0.05) in the labial and lingual/palatal crown torque IIA groups, respectively.
Conclusions: Torque was under-expressed when the teeth were moving labially, and fully- or over-expressed when moved lingually, indicating Invisalign’s inefficiency in torqueing incisors in the labial direction.
</abstract>

Reliability of torque expression by the Invisalign® appliance: A retrospective study

<abstract>
<title style='display:none'>Abstract</title>
<sec>
<title style='display:none'>Background</title>
Numerous studies rating dentofacial aesthetics have been conducted by using the Likert Scale or the Visual Analogue Scale (VAS). The Likert Scale is an assessment tool consisting of items that require respondents to rank a query using graded declarative statements. Alternatively, the VAS is a tool that requires the respondents to place a mark along a horizontal line to rate a particular item.
</sec>
<sec>
<title style='display:none'>Objective</title>
This systematic review aimed to identify the validity and reliability of the Likert scale and VAS in evaluating dentofacial aesthetics. A second objective was to identify which scale is preferable for use by clinicians and patients in determining dental aesthetics.
</sec>
<sec>
<title style='display:none'>Search methods</title>
With no language limitations, a comprehensive electronic database search was conducted in the PubMed, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, Ovid, and OpenGrey databases using keywords and Mesh terms combinations: (“Likert scale” OR “Likert”) AND (“visual analogue scale” OR “VAS”) AND (“aesthetic*” OR “facial*” OR “dental*” OR “dentist*”). The selection criteria were set based on the PICO format. Population (P): Laypeople and/ or dental clinicians; Intervention (I) and Control (C): Likert Scale and Visual Analog Scale for measuring dentofacial aesthetics; Outcome (O): Validity, reliability, and the patient’s or clinician’s preference for using the Likert Scale or the Visual Analog Scale for measuring dentofacial aesthetics. The risk of bias was assessed using the STROBE checklist for observational studies and Version 2 of the Cochrane Risk of Bias Tool for Randomized Trials (RoB 2) for randomized controlled trials. The results were summarised qualitatively; no meta-analysis was conducted due to the high level of heterogeneity of the included studies.
</sec>
<sec>
<title style='display:none'>Results of the synthesis</title>
Both the Likert Scale and VAS are valid and reliable for scoring dentofacial aesthetics but each have their own advantages in aesthetic evaluation. There were different preferences for the two scoring methods.
</sec>
<sec>
<title style='display:none'>Conclusions</title>
Overall, there is insufficient data to draw a conclusion that the VAS or the Likert scale is superior. Either of these scales may be used to rate dentofacial aesthetics.
</sec>
</abstract>

Likert scale versus the visual analogue scale in evaluating dentofacial aesthetics: a systematic review

<abstract>
<title style='display:none'>Abstract</title>
<sec>
<title style='display:none'>Introduction</title>
In recent times, chatbots have played an increasing and noteworthy role in the field of medical practice. The present research was conducted to evaluate the accuracy of the responses provided by ChatGPT and BARD, two of the most utilised chatbot programs, when interrogated regarding orthodontics.
</sec>
<sec>
<title style='display:none'>Materials and methods</title>
Twenty-four popular questions about conventional braces, clear aligners, orthognathic surgery, and orthodontic retainers were chosen for the study. When submitted to the ChatGPT and Google BARD platforms, an experienced orthodontist and an orthodontic resident rated the responses to the questions using a five-point Likert scale, with five indicating evidence-based information, four indicating adequate information, three indicating insufficient information, two indicating incorrect information, and one indicating no response. The results were recorded in Microsoft Excel for comparison and analysis.
</sec>
<sec>
<title style='display:none'>Results</title>
No correlation was found between the ChatGPT and Google BARD scores and word counts. However, a moderate to significant relationship was observed between the scores and several listed references. No significant association was found between the number of words and references, and a statistically significant difference was observed in both investigators’ numerical rating scales using the AI tools (<italic>p</italic> = 0.014 and <italic>p</italic> = 0.030, respectively).
</sec>
<sec>
<title style='display:none'>Conclusion</title>
Generally, ChatGPT and BARD provide satisfactory responses to common orthodontic inquiries that patients might ask. ChatGPT’s answers marginally surpassed those of Google BARD in quality.
</sec>
</abstract>

An evaluation of orthodontic information quality regarding artificial intelligence (AI) chatbot technologies: A comparison of ChatGPT and google BARD

<abstract>
<title style='display:none'>Abstract</title>
<sec>
<title style='display:none'>Objective</title>
Using finite element analysis (FEA), the aim of the present study was to evaluate the effects of different aligner trimline extensions and attachment sizes on maxillary first and second molars under expansive forces delivered by clear aligner therapy
</sec>
<sec>
<title style='display:none'>Methods</title>
The study utilised 3 mm and 4 mm horizontal rectangular attachments on the maxillary first and second molars. Two main models were created: a High and Flat Trimline Aligner (HTLA), and a Low and Flat Trimline Aligner (LTLA). Six distinct model variations were created for the analysis: (1) LTLA and no attachment (NA), (2) LTLA and 3 mm horizontal rectangular attachment (3HA), (3) LTLA and 4 mm horizontal rectangular attachment (4HA), (4) HTLA and NA, (5) HTLA and 3HA, (6) HTLA and 4HA.
</sec>
<sec>
<title style='display:none'>Results</title>
In all models, the crowns of the maxillary molars exhibited buccal displacement, whereas the root displayed palatal displacement. The LTLA-NA model had the greatest displacement of all models, whereas the HTLA-4HA model had the lowest displacement. The greatest PDL stress value was identified in the coronal third region of the palatal root of the molars.
</sec>
<sec>
<title style='display:none'>Conclusion</title>
Buccal tipping of the molars was observed during aligner expansion in all models. By increasing the attachment size and heightening the aligner trimline extension, the occurrence of buccal tipping was significantly reduced.
</sec>
</abstract>

Does the trimline extension and attachment size affect maxillary arch expansion in clear aligner therapy ? A finite element study

<abstract>
<title style='display:none'>Abstract</title>
<sec>
<title style='display:none'>Objectives</title>
This study compares the effectiveness of face mask therapy applied after rapid maxillary expansion (RME) in 4- to 11-year-old patients with objective co-operation data collected using thermal sensors. The null hypothesis was that there would be no difference in the effectiveness of the maxillary protraction.
</sec>
<sec>
<title style='display:none'>Materials and method</title>
Initial and post-treatment lateral cephalometric radiographs were taken of patients with maxillary retrognathia, aged between 4 to 7 years (6.1 ± 1.88, <italic>n</italic> = 13) and 8 to 11 years (9.4 ± 1, <italic>n</italic> = 12) of age. An RME was performed for at least 10 days. The face mask protraction force was set to 450 g per side, and the recommended usage was 10 hr per day. TheraMon® microsensors were integrated into the face mask.
</sec>
<sec>
<title style='display:none'>Results</title>
The daily usage was significantly higher in the younger age group (8.9 ± 1.8 hr) compared to the older group (7.1 ± 0.9 hr). The SNA angle, A-Nasionperp (mm), ANB angle, Wits (mm), maxillary depth, ANS-Me (mm), the molar relationship (mm) and overjet (mm) significantly increased in both groups. Co-A (mm), the saddle angle, articular angle and UL-E Line (mm) showed a significant increase only in the older group, while the L1-A/Pg decreased significantly. The SNB angle decreased significantly only in the younger group. There was no statistically significant difference in the delta values between the two groups.
</sec>
<sec>
<title style='display:none'>Conclusion</title>
The null hypothesis was partly rejected since no difference was observed in the examined skeletal and soft tissue parameters.
</sec>
</abstract>

Comparing the efficiency of maxillary protraction using digital cooperation monitoring in ages 4–7 and 8–11: a prospective study

<abstract>
<title style='display:none'>Abstract</title>
<sec>
<title style='display:none'>Introduction</title>
Social media, particularly Instagram and Facebook, are commonly used for advertising orthodontic treatment.
</sec>
<sec>
<title style='display:none'>Aim</title>
The aim of the present study was to explore the perceptions towards social media marketing by young adults seeking orthodontic treatment in Malaysia.
</sec>
<sec>
<title style='display:none'>Materials and methods</title>
This was a qualitative study using semi-structured in-depth interviews of 15 young adults aged between 22- and 30-years old. The participants were selected through purposive sampling from multiple private and public clinics within the Klang Valley, Malaysia. Data were transcribed verbatim into Microsoft Word and coded using the NVivo12 software. Thematic analysis was applied to investigate the data.
</sec>
<sec>
<title style='display:none'>Results</title>
The perceptions of young adults on social media marketing of orthodontic treatment generated six themes which were categorised as positive (source of information, good marketing strategy, convenience, and a means to improve connection and communication) or negative (false or misleading information and the presence of disingenuous social media profiles). Seven factors influenced the subject’s decision-making process which were social media features, online trends, treatment costs, clinic location, third parties, knowledge and the availability of online information.
</sec>
<sec>
<title style='display:none'>Conclusion</title>
Young adults mainly had positive perceptions towards orthodontic marketing through social media. The findings of this study provide important insights for dental practitioners, policymakers, and stakeholders on how young adults are using social media and the factors that influence their decision-making process when searching for orthodontic treatment providers.
</sec>
</abstract>

Perceptions towards orthodontic marketing through social media among young adults seeking orthodontic treatment: a qualitative study

<abstract>
<title style='display:none'>Abstract</title>
The treatment of Class II division 2 patients with palatally inclined upper incisors using lingual appliances is generally challenging due to difficulties in achieving upper incisor torque control. The present case series aims to describe a simple method combining lingual appliances and mini-screws for the non-surgical management of two severe Class II division 2 patients presenting with deep overbites and gummy smiles. The treatment plans involved initial bite opening and upper incisor torque recovery, followed by distalisation of the entire upper arch using mini-screw anchorage. In one case, additional anterior labial mini-screws were necessary to assist incisor intrusion and complete upper arch levelling. Favourable treatment results suggest that lingual appliances, when combined with mini-screws and pre-torqued arch wires, may offer an effective approach for the non-surgical management of severe Class II division 2 patients with deep overbites and gummy smiles.
</abstract>

The treatment of severe class II division 2 patients with deep overbites and gummy smiles using lingual appliances: a case series

<abstract>
<title style='display:none'>Abstract</title>
<italic>Introduction</italic>: The aim of this study was to assess the rate of tooth movement and discomfort experienced by orthodontic patients using a vibrational appliance (Tooth Masseuse).
<italic>Methods</italic>: In this randomised controlled trial (RCT), 66 consecutive patients were assigned to a control or experimental group. The experimental group was instructed to use a vibrational appliance for a minimum of 20 minutes per day. All of the patients had the same fixed appliance and a 0.014 inch thermal NiTi wire during the 10 week study period. Impressions of the mandibular six anterior teeth were taken at 4 time points: at the start of treatment, 5 weeks, 8 weeks, and at 10 weeks after commencement. Little’s Irregularity Index was used to record alignment and assess the rate of tooth movement. A discomfort score chart was used to evaluate patient pain levels at 5 time points.
<italic>Results</italic>: The experimental group showed a 65% reduction in irregularity at 10 weeks, while the control group showed a 69% reduction in irregularity over the same period. No significant differences in irregularity or pain levels were observed at any of the time points between the groups.
<italic>Conclusions</italic>: The results demonstrate that, for 20 minute use per day, there appears to be no clinical advantage in using the vibrational appliance for the early resolution of crowding or the alleviation of pain during initial alignment.
</abstract>

The effects of a vibrational appliance on tooth movement and patient discomfort: a prospective randomised clinical trial

<abstract><title style='display:none'>Abstract</title><sec><title style='display:none'>Aim</title>The aim of the present study was to characterise the chemical and mechanical properties of contemporary thermoplastic orthodontic materials.</sec><sec><title style='display:none'>Materials and methods</title>Four thermoplastic materials were tested: Clear Aligner (Scheu-Dental), ACE and A+ (Dentsply), and Invisalign (Align Technology). Eight appliances were fabricated from each material and a small portion from each was analysed by ATR-FTIR spectroscopy. The appliances were cut and, following metallographic grinding and polishing, were subjected to instrumented indentation testing (IIT) employing a Vickers indenter. Martens Hardness (HM), Indentation Modulus (EIT), Elastic to Total Work Ratio (elastic index (ηIT)) and Indentation Creep (CIT) were determined according to ISO 14577-1. The mean values of the mechanical properties were statistically analysed by one way ANOVA and Tukey Kramer multiple comparison test at a = 0.05.</sec><sec><title style='display:none'>Results</title>ATR-FTIR analysis identified that Invisalign was a polyurethane-based material, whereas the others were based on polyester, polyethylene glycol terephthalate (PETG). Invisalign showed higher hardness and modulus values, a slightly higher brittleness and lesser creep resistance compared with the PETG-based products.</sec><sec><title style='display:none'>Conclusions</title>The materials tested showed significant differences in their chemical structure and mechanical properties and therefore differences in their clinical behaviour are anticipated.</sec></abstract>

Chemical and mechanical characteristics of contemporary thermoplastic orthodontic materials

<abstract><title style='display:none'>Abstract</title><sec><title style='display:none'>Objectives</title>To evaluate the antibacterial properties and effects of an orthodontic adhesive containing copper nanoparticles (NPs) on the material’s shear bond strength.</sec><sec><title style='display:none'>Methods</title>Antimicrobial activity was analysed by a disk diffusion test against <italic>S. aureus, E. coli and S. mutans</italic>. 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 (<italic>p</italic> ≤ 0.05). The adhesive remnant index (ARI) was also assessed microscopically.</sec><sec><title style='display:none'>Results</title>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 (<italic>p</italic> = 0.004).</sec><sec><title style='display:none'>Conclusion</title>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.</sec></abstract>

An evaluation of the antibacterial properties and shear bond strength of copper nanoparticles as a nanofiller in orthodontic adhesive

<abstract><title style='display:none'>Abstract</title>Valid patient consent is a legal and ethical principle that is fundamental to healthcare provision. Oral health practitioners (OHPs) must understand the principles that need to be addressed to ensure that the consent given by a patient is valid. Failure to obtain consent may result in a negligence claim or a complaint of professional misconduct against the OHP. Orthodontic treatment is mostly elective but is not without risk to the patient. Obtaining and maintaining valid consent for orthodontic treatment presents additional challenges in comparison with other dental procedures as the treatment lasts over a longer time and is most commonly performed in adolescents. In addition, prospective patients need to be informed regarding ‘lifelong’ management in the retention phase to minimise the risk of relapse. The present paper outlines the principles of valid consent with particular regard to orthodontic treatment in the adolescent patient. OHPs must ensure that they are satisfied that the competent patient has the capacity to voluntarily consent. Clinicians must also recognise that valid consent is not a one-off ‘tick the box’ procedural exercise but an ongoing process of effective information sharing in light of changing laws and an ever-changing scientific evidence base within a patient-centred model of healthcare.</abstract>

Valid consent and orthodontic treatment

<abstract>
<title style='display:none'>Abstract</title>
Background: With the increasing use of computed tomography (CT) in oral diagnosis and treatment planning, concern has been expressed about the high levels of radiation used, and the associated risks.
Objectives: The purpose of this study was to compare the radiation doses of facial CT scans with the radiation doses taking a lateral cephalometric radiograph, a panoramic radiograph (OPG), an occlusal film, and an intra-oral periapical radiograph. Methods: An Alderson-Rando anthropomorphic phantom head was used for the analysis. Thirty-six lithium fluoride thermoluminescent dosimeters were placed in the phantom head in locations representing radiosensitive sites. Standard facial CT scans and conventional radiographs (lateral cephalometric, OPG, maxillary occlusal, intra-oral periapical) were then taken of the phantom head.
Results: The following radiation doses were measured: maxillo-mandibular CT scan, 2.1 mSv; maxillary CT scan, 1.40 mSv; mandibular CT scan, 1.32 mSv; lateral cephalometric radiograph, 0.005 mSv; OPG, 0.010 mSv; maxillary occlusal, 0.007 mSv; intra-oral periapical radiograph, 0.005 mSv.
Conclusions: CT scans produce significantly more ionising radiation than conventional radiographs. This factor should be taken into account when considering a CT scan as an alternative to a survey with conventional radiographs. While CT scans offer many advantages over conventional radiography the high radiation dose to patients, and the cost of this procedure should be considered.
</abstract>

Comparison of radiation levels from computed tomography and conventional dental radiographs

Timing of Facial Growth: A Study of Relations with Stature and Ossification in the Hand Around Puberty

Statement of Human and Animal Rights

Publication Ethics

Conflict of Interest Statement

Guidelines for Contributors 2021

Australasian Orthodontic Journal

The Australasian Orthodontic Journal (AOJ) is the official scientific publication of the Australian Society of Orthodontists. First published in 1967, the aim...

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The Australasian Orthodontic Journal (AOJ) is the official scientific publication of the Australian Society of...