In vitro study examines posterior torque impact on 3D mechanics of anterior teeth in clear aligner treatment.

INTRODUCTION: This study utilizes investigate the impact of posterior torques on the three-dimensional force exerted on the lower anterior teeth during the retraction in orthodontic clear aligners treatment. METHODS: Four groups of mandibular dental arch light-cured resin models will be created, including: mandibular posterior teeth with standard torque, mandibular posterior teeth with labial torque, and mandibular posterior teeth with lingual torque. Each group will consist of 12 sets of clear aligners. The aligners will be worn, and measurements will be taken using the six-axis measurement platform to evaluate the three-dimensional force exerted on the lower anterior teeth under various initial torques applied to the mandibular posterior teeth. SPSS 26.0 used for ANOVA analysis, α = 0.05 significance level. RESULTS: Comparing mandibular posterior teeth with standard torque to those with labial torque, no statistically significant changes were observed in buccolingual force. In the mesiodistal direction, mandibular incisors exhibited a significant decrease in distal force, while canines showed a significant increase. Both findings had a significance level of P < 0.05; Lingual torque on mandibular posterior teeth, compared to standard torque, led to a significant increase in lingual force for incisors and a significant increase in labial force for canines in the buccolingual direction (P < 0.05). Additionally, mandibular incisors exhibited a significant decrease in distal force in the mesiodistal direction (P < 0.05). CONCLUSION: Varying initial torques on mandibular posterior teeth significantly impact force on lower anterior teeth. Labial torque reduces lingual force on incisors and increases distal force on canines. Lingual torque increases lingual force on incisors and labial force on canines.

Duration of orthodontic treatment with clear aligners versus fixed appliances in crowding cases: a systematic review.

OBJECTIVE: To critically appraise and assess the currently observed evidence about the difference in orthodontic treatment duration between clear aligners and fixed appliances in crowding cases. MATERIALS AND METHODS: An electronic search without limitations was conducted from inception to June 2023 covering nine databases: The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Scopus, Web of Science, Google Scholar, Trip, CINAHL via EBSCO, EMBASE via OVID and ProQuest. Randomized controlled trials (RCTs) and matched non-randomized studies were included in this systematic review. Risk of Bias was assessed via Cochrane's tool (RoB 2) for RCTs and ROBINS-I tool for non-randomized studies. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework was employed to evaluate the overall quality of evidence. RESULTS: Out of the 3537 articles initially identified, ten eligible studies were included in this systematic review; six were RCTs. Only one study offered extraction-based treatment, while the other nine adopted non-extraction treatments. According to the GRADE, there is low evidence that treatment duration in mild to moderate crowding cases with clear aligners is similar to that in fixed orthodontic appliances. Meta-analysis was not administered due to high inconsistency. CONCLUSIONS: Based on currently available information, there was no significant difference in the treatment duration between the CA and FA groups in mild to moderate crowding cases. Further well-performed RCTs, especially in severe cases, are required. CLINICAL RELEVANCE: Time efficiency is an essential outcome measure for clinical orthodontic practice. While the type of appliance used is a critical determinant of treatment duration, orthodontists should be aware of other factors that can significantly impact treatment time, such as patient and treatment-related factors.

Innovations in Orthodontics: Skeletal Versus Dentoalveolar Expansion Utilizing Clear Aligners and TAD-Assisted Expanders.

Hypoplastic maxilla is a common skeletal anomaly that compromises function and esthetics. Beyond just a narrow-appearing smile, this abnormality presents significant restorative challenges in adult patients as it is often associated with crowding, compromised axial inclination of the teeth, lack of alveolar bone support, root proximity, and occlusal trauma.1 Recent research also confirms association of maxillary deficiency with nasal stenosis and a predisposition to compromised nasal airflow and pharyngeal collapse during sleep.2,3 Maxillary transverse skeletal deficiency is often but not always associated with posterior dental cross-bite. In most cases, maxillary posterior teeth are flared buccally and mandibular posterior teeth are excessively lingually inclined masking the underlying skeletal problem.4 Advances in 3D imaging in dentistry, namely ultra-low radiation cone-beam imaging technology, have significantly enhanced clinicians' ability to diagnose and subsequently treat a maxillary transverse deficiency.5.

Invisalign Lite: a cross-sectional investigation of orthodontist treatment-planning practices.

OBJECTIVES: To survey treatment-planning practices of orthodontists related to the Invisalign Lite clear aligner appliance (Align Technology, San Jose, Calif). MATERIALS AND METHODS: Patients satisfying inclusion and exclusion criteria and treated with Invisalign Lite were selected from a database containing more than 17,000 patients. Relevant data regarding treatment-planning practices were obtained from Align Technology's treatment-planning facility, ClinCheck, and evaluated. RESULTS: Most (n = 135; 79.9%) patients were female and had a median (interquartile range [IQR]) age of 30.5 (23.8, 43.1) years. The median (IQR) number of aligners for the sample was 23.0 (14, 28) for the maxilla and 24 (14, 28) for the mandible. Most (n = 122; 72.2%) patients required at least one additional series of aligners. More locations for interproximal reduction (IPR) were prescribed in the mandible (mean 1.91 [1.78]) than in the maxilla (1.03 [1.78]; P < .024) in the initial accepted plan of all patients. More teeth were prescribed composite resin (CR) attachments in the maxilla (P < .0001) in the initial accepted plan of all patients. Issues regarding tooth position protocols (n = 50; 53.3%) and requirement for additional IPR (n = 68; 45.3%) were reasons for treatment plan changes before acceptance of the initial treatment plan by orthodontists. CONCLUSIONS: More than 7 of 10 patients required at least one additional series of aligners after the initial series of Invisalign Lite aligners was completed. Prescription of IPR was more common in the mandible, and prescription of CR attachments was more common in the maxilla.

Orthodontic treatment of a patient with dentinogenesis imperfecta using a clear aligner system.

BACKGROUND: Orthodontic treatment for patients with dentinogenesis imperfecta (DGI) can be risky because of the fragility of their dental hard tissue. Although the Invisalign (Align Technology) clear aligner system should be a suitable orthodontic appliance for patients with DGI, to the authors' knowledge, there has been no related research. CASE DESCRIPTION: A 28-year-old woman with DGI sought treatment with a 1 mm open bite, edge-to-edge occlusion of the central incisors, and a bilateral Class III cusp-to-cusp molar relationship. Invisalign was applied for her treatment, and after 3 and one-half years of orthodontic therapy, a normal overjet and overbite were achieved, accompanied by retraction of the lower lip as well as a bilateral Class I molar relationship. In addition, there was no iatrogenic injury to the patient's teeth. PRACTICAL IMPLICATIONS: The Invisalign system may be a suitable orthodontic appliance for patients with DGI because clear aligners lessen the tensile stress to the teeth, decrease the number and area of bonds to the teeth, and offer protective effects through a full wrap of plastic that covers the crowns of the teeth.

Manufacturing of PEEK orthodontic baseplate and 3D-printed alloy components from an intraoral scan.

This paper demonstrates a digital manufacturing technique of a removable orthodontic appliance from an intraoral scan. An intraoral scan was made for the maxillary and mandibular arches. 3Shape Orthodontics Appliance Designer produced the virtual Hawley retainer, consisting of alloy components (Adam Clasps and Fitted Labial bow) and a base plate. The base plate design was modified to adapt to inserting the alloy components, which were combined using cold-cured acrylic. The finished Hawley retainer was assessed intraorally. The described technique emphasizes the design specifications of digitally designed and manufactured removable orthodontic appliances. A combination of additive and subtractive techniques was successfully employed to manufacture the alloy components and base plate. This novel method provides an alternative approach to manufacturing removable appliances with computer-aided design (CAD)/computer-aided manufacturing (CAM) technologies. The described process offers a precursor to digital manufacturing of other developed designs of dental appliances.

Noninvasive conservative management of anterior open bite treated with TADs versus clear aligner therapy.

OBJECTIVES: Anterior open bite can be treated non-surgically via molar intrusion using temporary skeletal devices (TAD). Clear aligner therapy (CAT) is recognized as a viable therapeutic modality for non-extraction treatment of adults with mild open bite. This study aimed to compare the treatment effect and mechanisms of open bite closure between patients treated with braces and TADs double arch intrusion and those treated with CAT. Treatment success at T3 was based on 1- positive overbite on ceph; 2- Change in the vertical dimension 3- post treatment POSI score equal to zero. MATERIAL AND METHODS: The TAD group includes 18 consecutively treated patients from the main author. The CAT group consisted of 16 selected patients from three different orthodontists. The observation time points were as follows: pretreatment (T1), end of molar intrusion and positive overbite achieved (T2), end of treatment (T3), at least 6-month follow-up (T4). Treatment changes were assessed by cephalometric analysis and frontal intraoral photo. RESULTS: At the end of treatment, 100% of the patient of the TAD group and 78,6% of the CAT group had a posi score of 0. The TAD group showed a significant reduction in vertical measurements (SN-MPA: -1,55° ± 0.41, LAFH: -3,05 ± 0.51 mm, U6-PP: -1.48 ± 0.30 mm), but the CAT group did not have significant changes for these variables. Both groups had significant increases in overbite from T1 to T3 (TAD: 4,32 ± 0,5 mm; CAT: 2,33 ± 0.56 mm), and overbite remained stable at T4. The CAT group did not have a significant upper molar intrusion, but a significant extrusion of 1.22 ± 0.42 mm of the lower incisor occurred. CONCLUSION: The TAD group achieved bite closure by upper molar intrusion, lower molar and incisors vertical control, and mandibular plane counterclockwise rotation, resulting in an improved AP and vertical relationship. The CAT group achieved bite closure through the lower incisor extrusion without significant change in the vertical dimension. CLINICAL RELEVANCE: This study provides relevant information about the skeletal and dental changes of open bite treatment with TADs double arch intrusion. The comparison with a control group treated with CAT confirms known information.

[Clear aligner in orthodontic retreatment].

Improper diagnosis and design, misusing orthodontic technique, relapse after orthodontic treatment, and poor patient compliance may lead to treatment failure, requiring orthodontic retreatment. While in such cases, patients usually have already had their teeth extracted, or are with periodontal, joint, and other dental problems, which often require multidisciplinary treatment. The retreatment of orthodontic patients is difficult, and the treatment options are limited. The characteristics of clear aligner treatment, such as comfortable and beautiful appearance, high degree of digital precision, and personalized tooth arrangement to simulate the final outcome, make it popular in the orthodontic retreatment. This article discusses and summarizes the details of orthodontic design, case monitoring, and the application of clear aligner in orthodontic retreatment of failed cases. Before starting treatment, the difficulty assessment tool (clear aligner treatment complexity assessment tool) can be used to evaluate the difficulty of clear aligner treatment. Orthodontists are recommended to treat orthodontic patients with clear aligners within their ability to avoid treatment failure. The key to the success of the extraction case treatment with clear aligner is to make the correct diagnosis and select the right cases. In the treatment planning, attention should be paid to the restoration of anterior tooth torque, making good use of molar distalization to obtain the space, vertical control, and improving posterior tooth relationship. Proper selection of cases and reasonable design in clear aligner treatment are expected to obtain tooth alignment, good intercuspation, normal overbite and overjet, periodontal health, parallel roots, and to achieve the goal of aesthetic, functional, stable, and healthy orthodontic treatment.

Does aligner refinement have the same efficiency in deep bite correction?: A retrospective study.

BACKGROUND: Refinements are very common in clear aligner treatments. The aim of this study is to assess whether the predictability of deep overbite correction is similar over several refinements using clear aligners (Invisalign, Align Technology, San Jose, Calif) and examine the accuracy of vertical movement and inclination change of individual teeth. METHODS: This retrospective study included 20 deep bite patients (7M and 13F; 32.63 ± 11.88 years old; an initial overbite of 5.09 ± 0.98 mm), consecutively treated from September 2016 and March 2023, who completed at least two sets of aligners, including refinements. The initial, predicted, and achieved models were exported from ClinCheck or OrthoCAD (Cadent Inc, Carlstadt, NJ) and superimposed via best-fit surface-based registration using SlicerCMF (version 4.9.0; cmf.slicer.org). We also examined 15 out of 20 patients who completed treatments. The overbite correction and changes in vertical movement and inclination for individual teeth were measured. Descriptive statistics and a paired t-test or Wilcoxon signed-rank test were performed. P < 0.05 was considered statistically significant. RESULTS: The mean accuracy of overbite correction was 37.63% after 1st set, followed by 11.19%, 6.32%, and 13.80% (2nd-4th sets), respectively. There were statistically significant differences between the predicted and achieved vertical movements and inclination changes for all teeth for the 1st and 2nd sets. For the completed cases, the mean overbite correction was 38.54% compared to the initially planned overbite correction, which is similar to one of the 1st set. Still, the vertical movements and inclination changes of all teeth present statistically significant differences between the initially planned and finally achieved movements except for maxillary lateral incisor torque. CONCLUSIONS: The most overbite correction occurs during the 1st set of aligners, and refinement treatment does not significantly improve the deep bite correction.

Impact of clear aligner therapy on masticatory musculature and stomatognathic system: a systematic review conducted according to PRISMA guidelines and the Cochrane handbook for systematic reviews of interventions.

BACKGROUND: Clear aligner therapy has gained popularity as a minimally invasive orthodontic treatment option. However, its impact on the masticatory musculature and the stomatognathic system is an area of growing interest, as it involves the adjustment of occlusion and tooth movement. This systematic review aims to comprehensively assess and synthesise existing evidence regarding the influence of clear aligner therapy on the masticatory musculature and the stomatognathic system. METHODS: An exhaustive search was performed on electronic databases that adhered to PRISMA guidelines. Clinical studies that evaluated the impact of patients receiving aligner orthodontic treatment on the muscles of the mastication and stomatognathic systems were included. A standardised data extraction form was devised for relevant variables. Two reviewers extracted the data variables. ROB-2 was used for bias evaluation in the selected studies. RESULTS: A total of six studies met the inclusion criteria. The wearing of clear aligners significantly impacted the muscles of mastication. Muscle activity and discomfort showed a significant alteration in the initial days of appliance placement. but this observation was temporary, with no significant changes thereafter in subsequent follow-up. Bite force reduction was also noted. All the studies evaluated showed good methodological quality. CONCLUSION: The review found that aligned orthodontic treatment may have a variable impact on muscles of mastication, with a potential for initial exacerbation of symptoms followed by possible improvement. However, due to the limited number of studies and their heterogeneous nature, further robust research is recommended to fully understand the relationship between aligned orthodontic treatment and masticatory muscles.

[Torque control of anterior teeth by clear aligners].

Appropriate torque control of anterior teeth is of great significance to obtain ideal orthodontic treatment outcome. Clear aligners are less effective in torque control of anterior teeth due to their special application mode and material properties. Therefore, it is important to investigate how to improve the torque control of anterior teeth by using clear aligners, with the expectation of providing guidance for clinicians. This article discussed the methods to control the torque of anterior teeth by using traditional fixed appliances, the efficiency of clear aligner in controlling the torque of anterior teeth, the difficult points of clear aligner in controlling the torque of anterior teeth and the therapeutic methods to better control the torque of anterior teeth by using clear aligners.

[Dental monitoring in clear aligner treatment].

The success of clear aligner treatment relies on rational treatment planning, favorable patients' compliance and high-quality clinical dental monitoring. High-quality clinical dental monitoring involves not only evaluation of real-time tooth position and treatment-designed tooth position, but also the assessment of the root-alveolar bone relationship. However, fluent imaging tests with ionizing radiation are not realistic in clinical practice. Regarding the rapid advances in digital techniques, biomechanism based method, image processing algorithm-based method and multimodal data fusion-based method all exhibit great potential in monitoring tooth movement. This paper introduced the progress and clinical application in those methods for clinicians' reference.

Orthodontic treatment demand for fixed treatment and aligners among young adults in middle Europe and South America - a questionnaire study.

BACKGROUND: Patients experiencing any malocclusion, may desire for treatment. However, there is no scientific information orthodontic treatment demand and the knowledge of young adults about orthodontic treatment. The aim of the study was to assess orthodontic treatment demand in young adults from Poland and Chile, their previous orthodontic experience and their knowledge on fixed and aligner orthodontic treatment. METHODS: The target group comprised people aged 18-30. The sample size was estimated as above 400 for each country. The survey was carried out in Polish and Spanish within 3 months and consisted of 25 questions delivered via social media. Comparisons were made between countries, age subgroups and gender. RESULTS: The response rate was 1,99%, what stands for 1092 responses, 670 from Chile and 422 from Poland, respectively. The percentage of young adults who were already treated was 42,9% in Poland and 25,0% in Chile. The ones planning to have orthodontic treatment within a year counted for 11,8% in Poland and 5,3% in Chile. Most young adults who want to be treated (20,6%) rely on doctor's recommendation on type of appliance while 14,7% of all respondents are interested solely in aligners. Most respondents have heard about aligners (58%). Direct provider-to-customer service without a doctor is not acceptable, neither in Poland (85,1%) nor in Chile (64,8%). Most young adults provided incorrect answers referring various aspects of aligner treatment. CONCLUSIONS: In both countries, patients demand to be treated and monitored by the orthodontist. A high percentage of patients want to be treated exclusively with aligners. Direct-to-consumer orthodontics does not seem attractive to patients. Young adults do not have adequate knowledge referring to aligner treatment. Many people want to be treated despite a previous orthodontic treatment.

Effects of clear aligners on the vertical position of the molar teeth and the vertical and sagittal relationships of the face: a preliminary retrospective before-after clinical trial.

INTRODUCTION: Despite the popularity of clear aligners, their predictability has not been assessed adequately. Moreover, no study has investigated their effects on numerous dentomaxillary variables. Therefore, this study was conducted for the first time, assessing several new or controversial items. The aim of the study was to evaluate the effects of clear aligners on the vertical position of the molar teeth and the vertical and sagittal relationships of the face. METHODS: This preliminary retrospective before-after non-randomized clinical trial was performed on 168 observations of 84 patients (33.60±9.28 years, 54 females) treated with 0.75mm Invisalign appliances. Pretreatment and posttreatment values were measured for: mandibular plane angle, occlusal plane angle, Y-Axis, ANB, facial angle, lower anterior facial height, overbite, and the distances of the molars from the palate and mandibular plane were measured. The alterations in parameters caused by treatment (delta values) were calculated for each measurement. Effects of treatment and some parameters on delta values were analyzed statistically (α=0.05). RESULTS: Mean±SD of ΔMP-FH, ΔOP-FH, ΔY-Axis, ΔLAFH, ΔNPog-FH, ΔANB, ΔOverbite, ΔSNB, Δ6-PP, Δ7-PP, Δ6-MP, and Δ7-MP were respectively 0.11±1.61, 0.80±1.56, 0.15±1.18, 0.07±0.91, -0.22±1.25, 0.03±0.62, 0.04±1.15, -0.06±1.14, -0.36±0.94, -0.32±1.14, 0.19±0.96, 0.18±1.10. Only the alterations in OP-FH, 6-PP, and 7-PP were significant (P≤0.011). Age, sex, treatment duration, or pretreatment mandibular plane angle were not correlated with any delta values. However, the pretreatment occlusal plane angle was negatively correlated with ΔOP-FH and ΔY-Axis. Crowding was correlated negatively with ΔOP-FH and ΔY-Axis and positively with ΔNPog-FH. Overjet was negatively correlated with ΔANB and ΔOverbite (P≤0.035). CONCLUSIONS: Invisalign intruded first/second maxillary molars and increased the occlusal plane angle. Age, sex, and treatment duration were not correlated with post-treatment anatomic alterations.