<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>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>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>
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>
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'>Introduction</title>
The purpose of this cross-sectional study was to survey the perception and attitude of Australian orthodontists toward accelerated orthodontic treatments.
</sec>
<sec>
<title style='display:none'>Methods</title>
An online questionnaire was distributed to 427 members of the Australian Society of Orthodontists. The questions related to: clinic demographics, familiarity with appliances/procedures to accelerate orthodontic treatment, the use of appliances/procedures to accelerate orthodontic treatment, and satisfaction with the outcomes when employing these appliances/procedures.
</sec>
<sec>
<title style='display:none'>Results</title>
The response rate was 42.38%. Of the respondents, 26.6% used customised fixed appliances which provided satisfactory outcomes. A small proportion of the respondents routinely used adjunctive procedures to accelerate treatment: 3.5% (<italic>n</italic>=6) corticotomies, 1.2% (<italic>n</italic>=2) piezocision, and 1.2% (<italic>n</italic>=2) intraoral vibrating devices.
</sec>
<sec>
<title style='display:none'>Conclusion</title>
Although a significant number of Australian orthodontists use customised fixed appliances to improve the efficiency of orthodontic treatment, the use of adjunctive procedures to accelerate tooth movement remains very low. Further research is needed to understand the possible limitations and restrictions surrounding this area of practice.
</sec>
</abstract>

Orthodontists’ perception and attitude toward accelerated orthodontic treatments in Australia

<abstract>
<title style='display:none'>Abstract</title>
<sec>
<title style='display:none'>Objectives</title>
An assessment of orthodontic treatment duration and results allows for measurable outcomes, goal-setting, and the establishment of patient management standards. It is important information that can be utilised for educational purposes in an orthodontic postgraduate program. The aim of this study was to determine correlations of the parameters within and between the Objective Grading System (OGS), Discrepancy Index (DI) and Treatment Complexity Index (TCI) and identify those factors associated with treatment outcomes and duration.
</sec>
<sec>
<title style='display:none'>Materials and methods</title>
This retrospective cohort study involved a consecutive sampling of 242 pre- and post-treatment patient records from the postgraduate orthodontic clinic between 2013 and 2017. The cases were assessed using the DI, OGS, and TCI pre-treatment. Treatment outcomes were assessed using the OGS. Spearman’s Rank Correlation Coefficients were computed within and between the indices. Multiple and logistic regressions were used to evaluate associations between treatment outcomes and duration, respectively.
</sec>
<sec>
<title style='display:none'>Results</title>
Within DI, significant correlations (<italic>p</italic> &lt; 0.05) were observed between overjet-overbite, overjet-occlusal relationship, overjet-crowding, overbite-anterior open bite, overbite-crowding, anterior open bite-lateral open bite, anterior open bite-crowding, lingual posterior cross bite-crowding. Within pre-OGS, significant correlations (<italic>p</italic> &lt; 0.05) were observed between alignment-marginal ridge, alignment-occlusal relationship, alignment-root angulation, overjet-interproximal contact, marginal ridge-buccolingual inclination, marginal ridge-overjet, marginal ridge-occlusal contact, marginal ridge-occlusal relationship, overjet-occlusal contact, overjet-occlusal relationship, overjet-root angulation, occlusal relationship-root angulation, interproximal contact-root angulation. Within TCI, functional appliance correlated with orthognathic surgery (<italic>p</italic> &lt; 0.001), rapid palatal expansion (RPE) (<italic>p</italic> = 0.005) and multidisciplinary collaboration (<italic>p</italic> = 0.001). Pre-OGS correlated with DI (<italic>p</italic> &lt; 0.001) and TCI (<italic>p</italic> = 0.026). Cephalometric (<italic>p</italic> = 0.002) and other conditions (<italic>p</italic> = 0.031) were associated with treatment outcomes. RPE was associated with extended treatment duration (<italic>p</italic> = 0.014).
</sec>
<sec>
<title style='display:none'>Conclusions</title>
DI, OGS, and TCI exhibited weak correlations within and between indices. Cephalometric values, clinical conditions, and RPE use should be carefully considered during treatment planning.
</sec>
</abstract>

Discrepancy index, treatment complexity index and objective Grading system: correlation between parameters, indices and implications for treatment

<abstract>
<title style='display:none'>Abstract</title>
<sec>
<title style='display:none'>Introduction</title>
To guide deep overbite treatment, the effectiveness of clear aligners and the influence of maxillofacial characteristics were assessed in levelling the curve of Spee (COS).
</sec>
<sec>
<title style='display:none'>Methods</title>
Forty-two patients underwent phased treatment using clear aligners. Digital dental models were created before and after treatment following which predicted outcomes, and dental cast measurements were conducted in addition to the analysis of lateral cephalometric and panoramic radiographs. The anticipated COS correction was compared with the actual correction achieved. Using multiple linear regression, associations between levelling effectiveness and clinical indicators were evaluated to establish prediction equations. <italic>P</italic> = 0.05 indicated statistical significance.
</sec>
<sec>
<title style='display:none'>Results</title>
The levelling effectiveness was 71.8 ± 19.0%. The regression model accounted for 88.5% of the variance in levelling effectiveness (<italic>F</italic>-value = 167.209, adjusted <italic>R</italic>2 = 0.885, Akaike information criterion [AIC] [E]=-146.94). The levelling effectiveness was related to the vertical skeletal pattern, the angulation of the mandibular incisors to the mandibular plane, the axial inclination of the mandibular anterior teeth, and the pre-treatment COS depth. Levelling effectiveness and other maxillofacial variables were not significantly related.
</sec>
<sec>
<title style='display:none'>Conclusion</title>
Clear aligners effectively level the COS. Patients with a larger Frankfort-mandibular plane angle, a pre-treatment COS depth, and an incisor-mandibular plane angle, more easily achieved COS levelling using clear aligners. Those with smaller mandibular incisor parallelism still achieved effective levelling.
</sec>
</abstract>

The effectiveness of clear aligners in levelling the curve of Spee and related maxillofacial factors in patients with a deep overbite

<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>
To investigate Nigerian children’s and their parents’ satisfaction with the children’s facial and dental appearances and their desire for orthodontic treatment, and to compare their assessments of treatment need with those determined by an orthodontist.
</sec>
<sec>
<title style='display:none'>Methods</title>
The subjects were 242 11–14 year-old schoolchildren randomly selected from private and public schools in the Ife Central Local Government area, Nigeria. A questionnaire was used to obtain information from the children and their parents of their liking of the facial and dental appearances of the children and the need and desire for orthodontic treatment. The children, the parents and an orthodontist used the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) to assess the need for treatment.
</sec>
<sec>
<title style='display:none'>Results</title>
More parents liked their child’s facial and dental appearances than the children liked themselves. Almost twice as many schoolchildren thought they needed (27 per cent) and desired (29 per cent) orthodontic treatment than their parents (15 per cent). Low, but statistically significant correlations, were found between the children’s, their parents’ and an orthodontist’s assessments of treatment need using the AC scale. Only 8 per cent of the children and 3 per cent of the parents considered that there was a ‘moderate-definite’ need of treatment. The orthodontist considered 38 per cent of the children had a ‘moderate-definite’ need of treatment.
</sec>
<sec>
<title style='display:none'>Conclusions</title>
The children’s responses suggest greater concern about their facial and dental appearances, a greater perception of the need for orthodontic treatment and greater desire for treatment than their parents. These findings require further investigation as previous studies have reported that parents are usually more motivated for orthodontic treatment than their children.
</sec>
</abstract>

Awareness of malocclusion and desire for orthodontic treatment in 11 to 14 year-old Nigerian schoolchildren and their parents

<abstract>
<title style='display:none'>Abstract</title>
<italic>Background</italic>: When limited resources are available for orthodontic treatment, it is important that those with the greatest need receive treatment.
<italic>Aims</italic>: The aims of this study were to determine the orthodontic treatment needs of Nigerian children and young adults attending a University Hospital as outpatients, and to determine if a relationship exists between social class and orthodontic treatment need.
<italic>Methods</italic>: Of 148 consecutive patients attending a hospital department for orthodontic treatment, 136 were children and young adults (67 males, 69 females) between 6 and 18 years of age. These subjects were assessed with the Dental Aesthetic Index (DAI), and classified into two social classes with the Standard Occupational Classification.
<italic>Results</italic>: Almost 30 per cent of the children and young adults presenting for treatment had “no/little” need of orthodontic treatment, 20 per cent had DAI scores between 26 and 30 indicating that treatment was “elective”, 15 per cent had a “desirable” need for treatment, and 35 per cent had a “mandatory” need for treatment. There was a significant association (<italic>p</italic> &lt; 0.05) between treatment need and social class: more subjects from the lower social classes (semi-skilled and unskilled occupations) needed orthodontic treatment than subjects from the higher social classes (professional, managerial, and skilled occupations). Conclusion: The study has shown that not all outpatients presenting/referred for orthodontic treatment “need” treatment. Patients from the semi-skilled and unskilled occupations were more likely to need orthodontic treatment than patients from the professional, managerial and skilled occupations.
</abstract>

Orthodontic treatment need of Nigerian outpatients assessed with the Dental Aesthetic Index

<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'>Objective</title>
To investigate the short-term optical, chemical and morphological changes in Invisalign appliances.
</sec>
<sec>
<title style='display:none'>Methods</title>
One ‘as-received’ Invisalign aligner, one ‘as-received’ Invisalign aligner immersed in artificial saliva for 14 days and 10 Invisalign aligners worn by 10 randomly selected patients for 14 days were used. Fourier transform infra-red microspectroscopy was used to characterise any molecular changes on the surfaces of the appliances, spectrophotometry was used to evaluate any changes in colour and transparency, scanning electron microscopy and energy dispersive X-ray microanalysis were used to examine the surface morphology and elemental composition of deposits on the surfaces of the aligners and gas chromatography-mass spectrometry was used to identify substances released from the aligners into the artificial saliva.
</sec>
<sec>
<title style='display:none'>Results</title>
Aligners worn for 14 days had microcracks, abraded and delaminated areas, localised calcified biofilm deposits and loss of transparency. Monomers and/or by-products were not released from the aligner suspended in artificial saliva for 14 days, which suggests that the material is chemically stable.
</sec>
<sec>
<title style='display:none'>Conclusions</title>
Further studies are required to evaluate how intra-oral conditions may influence the optical properties and chemical stability of the aligners.
</sec>
</abstract>

Short-term chemical and physical changes in Invisalign appliances

<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

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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...