Clear Aligner Treatment Research Articles

Effectiveness of palatal anchorage device (PAD) for maxillary anterior retraction with clear aligners using finite element study.

The palatal anchorage device (PAD) is commonly used in fixed appliance for anchorage, but the biomechanics of PAD in patients treated with clear aligners(CAs)remains poorly understood, especially in its elastic mode and force magnitude. This study aimed to assess the biomechanical effects of using PAD for retraction during clear aligner treatment (CAT) with the extraction of two maxillary first premolars. Four finite element models were created: (1) Incisors retraction (IR) with active contraction of the clear aligner only; (2) IR with PAD using different forces (50,75,100g) or not; (3) PAD without IR (forces of 50,75,100g), and (4) Different elastic directions (D1, D2, D3) from aligner to PAD without IR. IR caused lingual tipping and extrusion of the central incisors, as well as mesial and buccal tipping of the first molar. PAD during IR provided strong anchorage for the first molar, with elastics slightly increasing the lingual tipping and extrusion of the central incisors. Elastics applied to the U-shaped arch led to central incisor intrusion and reduced lingual retraction. The highest stress was observed on the mesial attachment of the canine. PAD effectively reinforced posterior anchorage in CAT, while anterior positioning facilitated anterior teeth intrusion. The biomechanical importance of the canine's mesial attachments in maxillary teeth treatment planning was highlighted.

Evaluating Clear Aligners Versus Fixed Appliances for Periodontal Patients: A Comprehensive Narrative Review of Current Evidence

Periodontal patients may face orthodontic problems because of bone support loss, such as maxillary incisor proclination, spacing, rotation, extrusion, pathologic tooth migration (PTM) or traumatic occlusion. Orthodontic treatment is therefore an element within the comprehensive treatment of periodontitis after the periodontal condition has stabilized. The presence of fixed appliances (FAs) promotes the accumulation of bacterial biofilm and impedes hygiene procedures. The increasing popularity of clear aligner (CA) treatment is due to the convenience of use, less discomfort, better esthetics, easier hygiene, lower failure rate, and shorter, less frequent visits. Therefore, the question arises whether treatment with aligners is a good solution for periodontal patients. To answer this question, the PubMed/Medline, Cochrane Library and EMBASE databases were searched using the following keywords: periodontitis, orthodontic treatment, clear aligners, multibracket orthodontic appliances, fixed appliance, root resorption, gingival recession and pathologic tooth migration. The search strategy identified 18 relevant studies. A total of 1090 participants took part in the analyzed studies. The available literature was analyzed in terms of the occurrence of root apex resorption, the possibility of treating pathologic tooth migration, the occurrence of gingival recession, periodontal health status and occlusal stability in patients treated with CAs and FAs. Despite statistically significant differences in terms of Plaque Index (PI), probing depth (PD), apical root resorption and gingival recession favor the use of CAs. However, these values are mostly of no clinical significance. It is possible to treat PTM with CAs, but it is limited by the high degree of tooth mobility and incisor inclination. Obtaining perfect occlusion is comparably difficult in both CA and FA treatment. When planning orthodontic treatment in patients with reduced periodontium, the use of both CAs and FAs should be considered. The choice of method would ultimately depend on the patient’s dental condition.

Artificial intelligence-supported clear aligner orthodontic technology

With the advancement of digital healthcare and artificial intelligence (AI) technologies, the full automation of clear aligner orthodontic technology has become feasible. Significant research findings and commercial applications have emerged in areas such as intelligent diagnosis of multimodal orthodontic data, orthodontic treatment decision-making, automated generation of digital treatment plans, and remote intelligent monitoring. However, in the development and application of AI software, it is imperative to address issues related to clinical risks, target populations, and compliance with medical device software regulations. This article analyzes and summarizes the applications and challenges of AI in clear aligner orthodontic diagnosis, treatment, and production processes. Furthermore, it explores potential future trends in this field, providing valuable insights for clinical reference.

Anchorage loss of the posterior teeth under different extraction patterns in maxillary and mandibular arches using clear aligner: a finite element study

BackgroundExtracting the premolars is an effective strategy for patients with bimaxillary dentoalveolar protrusion. Clear aligners (CAs) close the extraction spaces through shortening the length of aligners. The contraction force generated by the terminal of aligners makes the posterior teeth tip mesially, which is known as the roller coaster effect. This phenomenon is even worse in the 2nd premolar extraction cases. Posterior anchorage preparation is commonly used to protect the angulation of molars, taking the form of presetting distal tipping value. However, the distal tipping design aggravates the anchorage loss of anterior teeth simultaneously. This study aimed to explore the different anchorage loss of the posterior teeth when the 1st or 2nd premolars were extracted using CAs, respectively in maxillary and mandibular arches, further providing guidance for anchorage preparation design in clinical practice.MethodsTwo bimaxillary finite element models with different extraction patterns were established to simulate the anterior en-masse retraction process of the CAs. In Model 1, the maxillary and mandibular 1st premolars were extracted, while in Model 2, the 2nd premolars were extracted. Finite element analysis methods were utilized to analyze the tipping angle of the anterior and posterior teeth.ResultsCompared between two models, the anterior teeth exhibited a greater lingual inclination tendency and the posterior teeth exhibited a slighter mesial tipping tendency in Model 1 regarding individual tooth. The closer to the extraction spaces, the greater the tip, and the distal tipping tendency of the 1st premolars was more evident than the mesial tipping tendency of the 1st molars in Model 2. Compared between the maxillary and mandibular arches, the mesial tipping tendency of individual posterior tooth was more evident in the maxilla. In addition, the highest hydrostatic stress of the periodontal ligaments was concentrated on the cervical and apical parts directly adjacent to the extraction spaces, and it exhibited relatively uniform distribution in Model 1.ConclusionsThe individual posterior tooth showed the same mesial tipping direction but to different degree when the 1st or the 2nd premolars were extracted during clear aligner treatment. Presetting anchorage preparation design for the posterior teeth is essential to alleviate the roller coaster effect, especially in the 2nd premolar extraction cases. Furthermore, larger anchorage preparation value should be proposed for the maxillary posterior teeth.

Investigation of Changes in Tooth Colour After the Use of Different Aligners.

Clear aligner treatment is an orthodontic treatment that is custom-made with 3D printers without the use of conventional metal or porcelain wires and brackets. It is a modern orthodontic method used to correct tooth positions that need to be corrected aesthetically and functionally. Aim This study aimed to compare the discolouration of teeth and clear aligners after 15 days of full-time use of clear aligners. Materials and methods The 20 patients in the study group had used clear aligners for 45 days, including three different clear aligners for 15 days. In addition, 20 patients were included as a control group to measure the difference in tooth discolouration. Retaining attachments using G-Aenial (GC Corp, Tokyo, Japan) and 3M ESPE (St. Paul, MN, USA) flowable composites were placed crosswise to each patient in the distal regions of all lateral and canine teeth. The performance of three aligner plates (Zendura Flex (Bay Materials LLC, Fremont, CA, USA); Duran (ScheuDental GmbH, Iserlohn, Germany); and Taglus (Laxmi Dental Export Pvt. Ltd, Mumbai, India)), two fluid composite attachments, and two clear aligner cleaners regarding discoloration were tested. Each aligner was used for 15 days, and then the patient was moved to the next aligner. Colour change on the aligners and the patients' teeth were assessed from the canine to the middle third and mid-plane of the canine tooth using a VITA Easyshade V spectrophotometer (Bad Säckingen, Germany). An aligner cleaner was used immediately after the patients used their clear aligners, and then the measurements of the aligner color values were completed. The 120 aligners obtained were divided into two groups. Sixty aligners were treated with Fresh Guard (Efferdent, Lynchburg, VA, USA), and the other 60 were treated with Corega (GlaxoSmithKline, London, UK) tablets and stored in a glass of water. Results The colour stability of G-Aenial Flo was higher than that of the 3M ESPE fluid composite (p=0.040 and p=0.024). Our study determined that staining occurred in all the teeth we measured as a result of using aligner. Fresh Guard aligner cleaner caused more discoloration on Zendura and Duran aligners than Corega aligner cleaner (p<0.05). Taglus plaque was found to have more discoloration than Zendura and Duran aligner (p<0.05). Conclusion In conclusion, Duran clear aligners are preferable to other clear aligners in terms of discoloration. In addition, G-Aenial Flo can be recommended as an attachment or fluid composite because of its better color stability results.

Effects of curing lights on polymerization shrinkage of composite attachments in clear aligner treatment: A microcomputed tomography study

This study aimed to investigate the polymerization shrinkage of composite attachments and changes in attachment templates during bonding in clear aligner treatments. A total of 24 extracted teeth were divided into 4 groups, and plaster models were digitized. Attachment templates were produced with beveled attachments on premolars and rectangular attachments on molars. Polymerizations used a halogen curing light (800 milliwatts per square centimeter [mW/cm2] for 20 seconds) and light-emitting diode (LED) curing light in 3 modes (1000 mW/cm2 for 20 seconds, 1000 mW/cm2 for 10 seconds, and 3200 mW/cm2 for 3 seconds). The curing distance was 5 mm, and temperature changes were recorded with a thermal camera. Microcomputed tomography scanning measured volumetric and linear attachments before and after polymerization. Statistical analyses employed a 1-way analysis of variance with Bonferroni corrected Tukey post-hoc for multiple comparisons and the Kruskal-Wallis test for temperature change. Significant differences (P<0.001) were found in temperature among curing lights. The highest temperature was in the LED unit-extra mode, and the lowest was in the halogen curing unit. The LED unit for 20 seconds caused the highest temperature change. A significant difference (P= 0.048) in occlusal attachment length was found between the LED unit for 20 seconds and the LED unit-extra mode. Polymerization resulted in increased attachment template thickness across all groups, with significant changes noted in the halogen unit, LED unit for 20 seconds, and LED unit-extra mode. Temperature generated during polymerization varied between halogen and LED curing lights. Significant differences were found in attachment length at the occlusal level and template thickness postpolymerization. Preferences in attachment bonding protocols may affect the clinical precision of clear aligner treatments.

Panoramic evaluation of external root resorption in mandibular molars during orthodontic treatment: a comparison between root-filled and vital teeth treated with fixed appliances or clear aligners

BackgroundThis investigation compared the extent of external apical root resorption (EARR) in root-filled teeth (RFT) and their contralateral vital pulp teeth (VPT) counterparts during orthodontic treatment (OT) with clear aligner (CA) treatment or fixed appliance (FA) treatment.MethodsSixty-six patients with similar baseline American Board of Orthodontics (ABO) discrepancy index scores were divided into two groups: 37 patients (21 females, 16 males; mean age 17.45 ± 2.67 years) in the FA group, and 29 patients (18 females, 11 males; mean age 18.33 ± 1.96 years) in the CA group. Digital panoramic radiographs captured pre- and post-OT were used to measure tooth lengths and root surface measurements in mandibular molars. EARR in both RFT and contralateral VPT was evaluated pre- and post-OT. Statistical analysis employed paired t-tests, independent t-tests, and analysis of covariance (ANCOVA) (p < .05).ResultsAll teeth exhibited varying degrees of EARR following OT. FA treatment resulted in significantly longer treatment duration (p < .05) and greater EARR compared to CA treatment (p < .05). Moreover, statistically significant differences in EARR were observed within both groups between RFT and VPT (p < .05).ConclusionsComparison of pre- and post-OT radiographs revealed different degrees of EARR in all teeth. CA treatment resulted in less frequent and less severe EARR compared to FA treatment. RFT demonstrated greater resistance to EARR than VPT in both treatment groups.

Effects of clear aligners combined with maxillary protractor on mixed dentition patient with skeletal class Ⅲ malocclusion: a finite element study

Objective: To compare the effects of expansion screw with maxillary protractor and clear aligners combined with maxillary protractor on the maxilla and maxillary dentition of mixed dentition patients with class Ⅲ skeletal malocclusion using finite element analysis, further providing clinical guidance for clear aligner treatment. Methods: A finite element model was established based on maxillofacial cone-beam CT data of a 10-year-old boy with mixed dentition, class Ⅲ skeletal malocclusion, who visited Department of Orthodontics, School of Stomatology, The Fourth Military Medical University in January, 2024. The expander with protractor group (group A) and the clear aligners with protractor group (group B) were divided. The arch was extended by 0.25 mm in both groups, and the forward pull force was 2.94 N (working condition 1) and 4.90 N (working condition 2), respectively. The initial displacement trend of maxilla and maxillary dentition in two groups under two working conditions were evaluated. Results: Under two working conditions, the maxilla of both groups showed clockwise rotation and labial inclination. The labial inclination of maxilla was more significant in clear aligners with protractor group, about 2.2-3.0 times that of expander with protractor group under the same working condition. Maxillary dentition showed mesial and buccal displacement, with anterior teeth extrusion and posterior teeth intrusion in two groups under two working conditions. Under the working condition 1 and 2, the labial displacement of central incisor of clear aligners with protractor group (-0.065, -0.089 mm) were greater than that in expander with protractor group (-0.024, -0.024 mm). Under two working conditions, the posterior teeth of expander with protractor group moved close to the buccal bodily direction, while those of clear aligners with protractor group moved tilted towards the buccal direction in the horizontal direction. The forward displacement trend of maxilla and maxillary dentition in clear aligners with protractor group was more obvious than expander with protractor group with the increase of the forward pull force. Under two working conditions, the anterior teeth' s hydrostatic stress of periodontal membrane and the equivalent stress of alveolar bone in clear aligners with protractor group were higher than those in expander with protractor group, mainly concentrated on the labial cervical region of the incisor. Conclusions: Clear aligners combined with maxillary protractor can produce forward force on the maxilla, but labial inclination occurs in the anterior teeth. It can be an effective orthopedic treatment strategy for mixed dentition patients with class Ⅲ skeletal malocclusion.

Evaluation of effects of different sizes and shapes of attachments during rotation, tipping, and torquing in clear aligner therapy - A finite element study.

To evaluate the effect of different shapes and sizes of attachments used for rotation, tipping, and torquing tooth movement in clear aligner therapy. Using computer-aided design/computer-aided manufacturing technology, 15 replicas of the upper right human canines were produced. Finite element analysis (FEA) was utilized to mimic tooth movement by applying a constant force of 2.942 N to these models, which contained various forms and sizes of composite attachments. Analysis was done on the stress on different dental structures and the displacement of the attachments. The outcomes demonstrated that tooth movement during clear aligner treatment was considerably impacted by attachment size and shape. Rectangular beveled attachments with dimensions of 3.5 mm × 1.2 mm × 3.5 mm showed the greatest rotating mobility. Triangular beveled attachments with dimensions of 5 mm by 0.8 mm by 2 mm produced the most displacement during tipping motion. For torquing motions, rectangular power ridge attachments with dimensions of 0.5 mm × 0.5 mm × 5 mm worked well. The size and geometry of composite attachments were shown to be extremely important in regulating tooth movement during clear aligner treatment, according to this FEA research. Greater displacement is produced when smaller attachments with less surface area dissipate more force. When using clear aligner therapy, orthodontists may optimize treatment plans, shorten treatment times, and provide more predictable results by having a better understanding of the biomechanics of various attachment designs.

A finite element analysis of the effects of semipontic design on tooth movement during mesialization of the mandibular second molar with clear aligners

Loss of the mandibular first molar is common in orthodontic patients. One treatment option is the mesialization of the second and third molars. This study aimed to investigate the displacement and type of movement in the second molar during mandibular second molar mesialization with clear aligner treatment using finite element analysis in configurations with or without pontic, semipontic, and anatomic pontic for the edentulous space. Mesialization of the mandibular second molar with clear aligner treatment was simulated using the AlGOR Fempro program (ALGOR, Inc, Pa) with 3 different configurations. In the transverse direction, the highest rotation occurred in the anatomic pontic model, whereas the lowest rotation was in the semipontic model. In the sagittal axis, although tooth movement was realized by tipping in all scenarios, the semipontic model showed the closest movement to translation because of a higher rate of crown-root movement. In the vertical axis, although extrusion occurred in all configurations, the semipontic model showed the least extrusion forces, whereas the anatomic pontic model showed the most. Mesiobuccal rotation, mesial tipping, and extrusion were observed in all models. However, the semipontic design had the closest movement to translational. Further randomized, controlled clinical trials are needed to evaluate the effects of different pontic designs on tooth movements.

Staging of Orthodontic Tooth Movement in Clear Aligner Treatment: Macro-Staging and Micro-Staging—A Narrative Review

Abstract: Aims: This review aims to analyze the multiple factors affecting the staging of the orthodontic tooth movement during clear aligner treatment and to provide an efficient work methodology in this regard during digital treatment planning. Materials and Methods: A literature search was conducted on electronic databases (Pubmed, Scopus, Google Scholar and CNKI). The results of the present study have been divided into several sections: (1) definition and concept of staging, (2) basic principles of clear aligners, (3) macro-staging, (4) micro-staging, and (5) limitations. Results: The terminology of macro-staging and micro-staging proposed in this paper aims to be a first step towards a more detailed analysis of staging. The macro-staging constitutes the general biomechanics of movements that need to be prioritized to meet the objectives of the treatment plan. It provides a comprehensive view of the movements occurring in each dental arch. The micro-staging constitutes the biomechanics of movements for each individual tooth. This involves studying the movements in the different planes of space in which each tooth is programmed, deciding if they are compatible, and having strategies to create space to avoid lack of expression. Conclusions: Further studies should focus on exploring different staging approaches to address similar malocclusions to determine which are the most effective and applicable to clinical practice.

Optimal positions of clear aligner attachments to achieve lower canine tipping and bodily movement using finite element analysis

Background/purposeClear aligners are popular orthodontic tools because of their relatively aesthetic appearance and convenience of use. Nevertheless, bodily tooth movements still present challenges. This study evaluated various configurations of attachments placed on the mandibular canine in terms of the efficiency of canine bodily movement and correction of tipping. Materials and methodsA finite element model of the mandible was constructed to investigate the effects of various attachment configurations on the overall bodily movement and undesirable tipping of a mandibular canine. Canine movements were categorized into four types, namely tipping and bodily movements in the mesial and distal directions. The size and shape of the attachments were fixed, but their placement and orientation were varied. Five and seven attachment configurations were evaluated for their influence on tipping and bodily movements, respectively. ResultsAttachment configuration significantly influenced mandibular canine tipping. The mesial occlusal–distal cervical and mesial occlusal–mesial cervical configurations had notable effects on mesial tipping, and the mesial occlusal–mesial cervical configuration excelled in distal tipping by increasing strain by 33.1%. The mesial occlusal–mesial cervical attachment configuration consistently had superior efficiency in facilitating both mesial and distal bodily movements of the canine. ConclusionThe mesial occlusal–mesial cervical attachment configuration excelled in all four types of canine movement. Irrespective of the attachment configuration, canines tend to move overall with slight tipping due to skeletal resistance and their center of rotation. The attachment configuration is crucial to the success of clear aligner treatment and must be carefully considered in clinical practice.

Effectiveness of different intrusion modes of maxillary anterior teeth with mini-implants in clear aligner treatment: a three-dimensional finite element analysis

BackgroundThe intrusion of maxillary anterior teeth is often required and there are various intrusion modes with mini-implants in clear aligner treatment. The objective of this study was to evaluate the effectiveness of maxillary anterior teeth intrusion with different intrusion modes, aiming to provide references for precise and safe intrusion movements in clinical practice.MethodsCone-beam computed tomography and intraoral optical scanning data of a patient were collected. Finite element models of the maxilla, maxillary dentition, periodontal ligaments (PDLs), clear aligner (CA), attachments, and mini-implants were established. Different intrusion modes of the maxillary anterior teeth were simulated by changing the mini-implant site (between central incisors, between central and lateral incisor, between lateral incisor and canine), loading site (between central incisors, on central incisor, between central and lateral incisor, between lateral incisor and canine), and loading mode (labial loading and labiolingual loading). Ten conditions were generated and intrusive forces of 100 g were applied totally. Then displacement tendency of the maxillary anterior teeth and CA, and stress of the PDLs were analyzed.ResultsFor the central incisor under condition L14 and for the canine under conditions L11, L13, L23, and L33, the intrusion amount was negative. Under other conditions, the intrusion amount was positive. The labiolingual angulation of maxillary anterior teeth exhibited positive changes under all conditions, with greater changes under linguoincisal loading. The mesiodistal angulation of canine exhibited positive changes under labial loading, while negative changes under linguoincisal loading except for condition L14.ConclusionsThe intrusion amount, labiolingual and mesiodistal angulations of the maxillary anterior teeth were affected by the mini-implant site, loading site, and loading mode. Labial and linguoincisal loading may have opposite effects on the intrusion amount of maxillary anterior teeth and the mesiodistal angulation of canine. The labiolingual angulation of the maxillary incisors would increase under all intrusion modes, with greater increases under linguoincisal loading.

The effect of clear aligner treatment on masticatory muscles (masseter, temporalis) activity in adults: a systematic review and meta-analysis.

The use of clear aligners is becoming more common for aesthetic orthodontic treatment, but there are still concerns about how they affect mastication biomechanics in the short and long term. The clear aligners treatment (CAT) mechanism changes the position of the mandible and maxilla, especially impacting the masseter muscle. Surface electromyography (sEMG) proves to be a useful method to evaluate masticatory muscle activity (MMA). To analyze the effect of clear aligners treatment on alterations in masticatory muscles (masseter, temporalis) using surface electromyography. Five databases (PubMed, Web of Science, SCOPUS, Cochrane Library, and Google Scholar) were searched up to March 2024. Studies in which MMA was evaluated after the installation of orthodontic clear aligners. Screening, data extraction, and quality assessments were performed by four investigators independently. The data, which evaluated temporalis and masseter muscle characteristics during CAT using surface electromyography, was extracted, and the quality of the studies was evaluated. The risk of bias was assessed using the Newcastle-Ottawa Scale (NOS). Six studies (two prospective cohort studies, three observational longitudinal studies, and one observational longitudinal case-control study) with low and moderate risk of bias were included in the qualitative synthesis. Six of these were also included in the meta-analysis. Our study investigated the dynamics of masseter and temporalis muscle activity during CAT. The results show that during maximal voluntary clenching, the masseter muscle demonstrated a significant initial increase (P < .05) followed by a subsequent non-significant decrease. It also showed that submaximal voluntary clenching consistently exhibited a significant reduction in muscle activity throughout the study period (P < .01). Assessment of muscle activity at the mandibular resting position revealed a variety of responses, with some participants showing a significant increase while others exhibited non-significant changes (P < .05, P > .05, respectively). However, the meta-analysis showed a non-significant difference in measuring masseter and temporalis muscles activity during CAT. Based on existing evidence, it is reasonable to conclude that CAT affected MMA. During maximal voluntary clenching, masseter muscle activity initially increased but later decreased, while temporalis muscle activity showed mixed results. Submaximal voluntary clenching revealed a consistent decrease in muscle activity over time. Mandibular resting position assessments showed both increases and no significant changes in muscle activity. However, the existing literature is insufficient to draw concrete conclusions; therefore, well-conducted further research is needed to confirm this statement. This systematic review and meta-analysis were registered in the International Prospective Register of Systematic Reviews (PROSPERO CRD42024522231).

Predicting Outcome in Clear Aligner Treatment: A Machine Learning Analysis.

Background/Objectives: Machine learning (ML) models predicting the risk of refinement (i.e., a subsequent course of treatment being necessary) in clear aligner therapy (CAT) were developed and evaluated. Methods: An anonymized sample of 9942 CAT patients (70.6% females, 29.4% males, age range 18-64 years, median 30.5 years), as provided by DrSmile, a large European CAT provider based in Berlin, Germany, was used. Three different ML methods were employed: (1) logistic regression with L1 regularization, (2) extreme gradient boosting (XGBoost), and (3) support vector classification with a radial basis function kernel. In total, 74 factors were selected as predictors for these methods and are consistent with clinical reasoning. Results: On a held-out test set with a true-positive rate of 0.58, the logistic regression model has an area under the ROC curve (AUC) of 0.67, an average precision (AP) of 0.73, and Brier loss of 0.22; the XGBoost model has an AUC of 0.67, an AP of 0.74, and Brier loss of 0.22; and the support vector model has a recall of 0.61 and a precision of 0.64. The logistic regression and XGBoost models identify predictors influencing refinement risk, including patient compliance, interproximal enamel reduction (IPR) and certain planned tooth movements, for example, lingual translation of maxillary incisors being associated with the lowest risk of refinement and rotation of mandibular incisors with the highest risk. Conclusions: These findings suggest moderate, well-calibrated predictive accuracy with both regularized logistic regression and XGBoost and underscore the influence the identified factors have on the risk of refinement in CAT, emphasizing their importance in the careful planning of orthodontic treatment and the potential for shorter treatment times, less patient discomfort, and fewer clinic visits. Identification of at-risk individuals could support tailored clinical decision-making and enable targeted interventions.

Knowledge differences between general practitioners and orthodontists about Invisalign clear aligner treatment – a cross-sectional survey-based study

ABSTRACT Purpose This study investigated the knowledge differences between general practitioners and orthodontists about the Invisalign system. Materials and methods A web-based survey regarding 10 Invisalign treatment domains was distributed to 161 orthodontists and 213 general practitioners. The responses were ranked using a Likert-type scale and analysed with the Chi-square test and Bonferroni adjustment. Results The response rate was 52.1% for general practitioners and 63.4% for orthodontists. Comparing Invisalign to conventional fixed appliances, orthodontists agreed/strongly agreed that Invisalign aligners are suitable for all types of cases (p = 0.001). Orthodontists also agreed that it causes less tooth discomfort (p = 0.01) and an increased number of attachments can affect its esthetic perception (p = 0.014) but general practitioners opted for the ‘Do Not Know’ option (p ≤ 0.01). General practitioners also responded ‘Do Not Know’ to whether Invisalign treatment finishes in a shorter duration (p = 0.001), achieves all types of tooth movement (p < 0.001) and results in better periodontal health (p = 0.001). Orthodontists were more likely to disagree/strongly disagree that Invisalign treatment results in less tooth root resorption (p = 0.008), better American Board of Orthodontics Objective Grading System and Peer Assessment Rating scores (p < 0.001) and low risk of relapse (p < 0.001), while general practitioners opted for the ‘Do Not Know’ option (p < 0.0001, p < 0.0001 and p < 0.0001, respectively). Conclusion Regarding Invisalign treatment, this study found that orthodontists were generally evidenced-based but general practitioners lacked such knowledge, suggesting that general practitioners must be provided with relevant evidenced-based information.

Effects of different intrusion patterns during anterior teeth retraction using clear aligners in extraction cases: an iterative finite element analysis.

Overtreatment design of clear aligner treatment (CAT) in extraction cases is currently primarily based on the clinical experience of orthodontists and is not supported by robust evidence on the underlying biomechanics. This study aimed to investigate the biomechanical effects of overtreatment strategies involving different maxillary anterior teeth intrusion patterns during anterior teeth retraction by CAT in extraction cases. A finite element model of the maxillary dentition with the first premolar extracted was constructed. A loading method of clear aligners (CAs) based on the initial state field was proposed. The iterative method was used to simulate the long-term orthodontic tooth movement under the mechanical load exerted by the CAs. Three groups of CAs were utilized for anterior teeth retraction (G0: control group; G1: incisors intrusion group; G2: anterior teeth intrusion group). Tooth displacement and occlusal plane rotation tendency were analyzed. In G0, CAT caused lingual tipping and extrusion of the incisors, distal tipping and extrusion of the canines, mesial tipping, and intrusion of the posterior teeth. In G1, the incisors showed minimal extrusion, whereas the canines showed increased extrusion and distal tipping tendency. G2 showed the smallest degree of posterior occlusal plane angle rotation, while the inclination tendency of the canines and second premolars decreased. 1. In CAT, tooth displacement tendency may change with increased wear time. 2. During anterior teeth retraction, the incisor intrusion pattern can provide effective vertical control for the lateral incisors but has little effect on the central incisors. Anterior teeth intrusion patterns can alleviate the inclination of canines and second premolars, resulting in partial relief of the roller-coaster effect.

A Bibliometric Analysis of Clear Aligner Treatment (CAT) From 2003 to 2023.

Clear aligner treatment (CAT) has been evolving over the past two decades. This study aims to conduct a comprehensive and up-to-date bibliometric analysis of publications related to CAT, presenting the research trends, landscapes, and hot spots in this field. All publications were retrieved from the Web of Science Core Collection from 2003 to 2023. In addition to a general analysis of research landscapes, the following items were analyzed, i.e., countries, institutions, authors, journals, publications, and keywords. A total of 1031 relevant publications were included in this study. From 2003 to the present, the number of publications and citations in this field showed an increasing trend. Italy led in terms of publication counts, and Sichuan University in China had the highest publication counts among institutions. In total, 33 scholars had published a minimum of 10 articles, and the collaborations among them were mostly within each country. The American Journal of Orthodontics and Dentofacial Orthopedics published the most relevant publications. "Predictability of tooth movements," "influencing factors for clinical efficacy," "biomechanics," and "patients' perception and periodontal health" stood out as the core research focus on CAT. Our study identified the most influential countries, institutions and authors, and their cooperative relationships, and detected hot research topics on CAT, calling for more high-quality international collaborative research in the future.

The Risks Behind Fixed Retainers After Orthodontic Treatment.

Bonded fixed retainers are frequently used nowadays as the main and often the only retention protocol after orthodontic treatment. The expectations for long-lasting lifetime stability of the occlusion led orthodontists to seek the ultimate retention protocol with minimal patient compliance. Fixed retainers have many disadvantages and risks that should be considered in advance. Different failures of fixed retainers are described and categorized. The workflow for the retreatment of relapse caused in spite of the fixed retainers is described with 3 case presentations: Open bite, Root movement and Bimaxillary protrusion, all treated with clear aligner treatment (CAT). A revised retention protocol is suggested.

Clinical limitations and its solutions of the digital clear aligner treatment

The digital clear aligner is widely used due to the convenience and efficiency of simultaneously manufacturing the entire aligner used in treatment with a single setup. However, due to the characteristics of clear aligners, which make it difficult to effectively transmit orthodontic force to the teeth compared to traditional brackets, the teeth do not move as planned, resulting in repeated refinements and increased treatment periods. The following measures have been proposed to solve these problems:1. Partial production of Clear aligner: Manufacturing the entire aligner not all at once but in stages, typically 8-10 at a time, allows for more precise management of the individual tooth movement. Additionally, adjustments can be made promptly if treatment does not go as planned.2. Direct 3D printing of clear aligners: Direct 3D printing offers the possibility of creating more efficient aligners that adhere more closely to the teeth than vacuum-formed ones. Moreover, effective tooth movement can be achieved by adjusting the aligner's thickness or designing structures to apply orthodontic forces as required.3. Digital hybrid treatment: Using 3D-printed brackets with two strands of NiTi wire allows for rapid and accurate tooth movement with gentle force. In particular, the ability to manufacture clear aligners and 3D-printed brackets together in a single digital setup enables various clinical applications. This not only shortens the treatment period but also allows for better treatment results.