Tooth Torque Research Articles

Euler-angle norms for tooth rotation, torque and tip.

The aim of the current study was to develop and describe a new measuring system for the orientation of a tooth in a digitalized cast of a jaw and provide new angular values for the rotation, torque and tip of maxillary and mandibular teeth. This retrospective cross-sectional study involved the utilization of a sub-group of extrinsic Euler-angles to derive optimal norm values per tooth in three different planes of orientation ('rotation', 'torque' and 'tip') by evaluating the digital representations of the teeth derived from a database containing over 17,500 patients. The process involved the entry of the .stl files of the jaw pairs into a fully automated software system (Smyl:Ai, Ulm, Germany) whereupon jaw alignment, teeth segmentation, landmark identification and visual validation of input files was conducted prior to calculation of the norm values for the three different planes of orientation. The digital scans in stereolithography (.STL)-file format of the upper and lower dentitions of 1914 individuals with optimal occlusion were chosen and evaluated. New mean (standard deviation) angular values were determined for the rotation, torque and tip of maxillary and mandibular teeth. The findings facilitate the reappraisal of rotation, torque and tip values currently acceptable as ideal. They will inform anthropologists and dental researchers about occlusion and alignment in orthodontic and non-orthodontic patients and provide baseline data for future studies. The methodology will also enable the evaluation of large numbers of data in relatively short timeframes.

Effect of different post materials and designs on upper central tooth torque and intrusion load: A finite element analysis study

The aim of this study was to examine the effects of post material type and the presence of ferrules on the torque and intrusion load of the upper central tooth using finite element analysis. The upper central tooth and surrounding tissues (cortical bone, cancellous bone, and periodontal ligament) were modelled in three dimensions using the Spaceclaim software. Five simulated models (SM) different modifications were made to this main model: metal cast post (SM1) and glass fiber post-core with zirconium crown and without a ferrule (SM2), metal cast (SM3) post and glass fiber post with a ferrule and zirconium crown (SM4) and only zirconium crown (SM5). In all five simulations, in order to simulate lingual root torque movement, a total load of 40grams was applied to the bracket slot as 20grams of force couples and in order to simulate intrusion movement, a load of 40grams was applied to the superior wall of the bracket slot. The stress caused by the applied loads on the root surfaces was determined using finite element analysis. Maximum principal stress (MPS) value was used in the comparison. The highest root surface MPS values for both intrusion and torque loads belonged to SM2 (3.864 and 0.379MPa, respectively). The presence of ferrules in both intrusion and torque loads reduced the stress by approximately half (from 3.864 to 2.004MPa). In all five models, the radicular area with higher stress was located in the cervical third on the lingual surface when both torque and intrusion loads were applied. The amount and localization of stress was affected by the type of post material. The variation in stress values between the materials remains within a safe range (0.099 and 3.87MPa), making both materials suitable for use under orthodontic forces.

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.

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.

Evaluation of stress and displacement of maxillary canine during the single canine retraction in the maxillary first premolar extraction cases- A finite element study.

This finite element study aimed to simulate maxillary canine movement during anterior teeth retraction. Three methods of maxillary canine movement including miniscrew sliding with high hooks (MSH), miniscrew sliding with low hooks (MSL), and the traditional sliding method (TS) without using miniscrews were simulated using three-dimensional finite element analysis. The initial displacement of the maxillary canine, the maximum principal stress of the periodontal ligament and the Von Mises stress were calculated. The distolingual tipping movements of the canine were shown in three movement modes. MSH showed a small tendency to lingual tipping movement and a extrusion movement while MSL had the largest lingual inclination. TS demonstrated a tendency toward distolingual torsion displacement. Compressive stress values were mainly concentrated in the range - 0.003 to -0.006MPa. For tensile stress, the distribution of MSH and MSL was concentrated in the range 0.005 to 0.009MPa, TS was mainly distributed about 0.003MPa. Von Mises equivalent stress distribution showed no significant difference. The loss of tooth torque was inevitable, irrespective of which method was used to close the extraction space. However, miniscrew application and higher hooks reduced the loss of torque and avoided lingual rotation. This study shows that miniscrew implants with different hooks can better control the movement of the maxillary canines. The non-invasive nature of the finite element analysis and its good simulation of dental stress and instantaneous motion trend have a clinical advantage in the analysis of tooth movement.

Clinical outcomes of arch expansion with Invisalign: a systematic review

ObjectiveThis study aims to assess the scientific evidence regarding the clinical outcomes of Invisalign therapy in controlling orthodontic tooth movement.Materials and methodsAn electronic search was conducted on PubMed, Cochrane Library, Web of Science, Embase, and Scopus from November 2015 to November 2022 to identify relevant articles. Methodological shortcomings were highlighted, and an evaluation of the quality of the included studies was completed using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool.ResultsFifteen non-randomized controlled trials were included in the analysis. Most non-randomized controlled trials (n=11; 73%) were rated with a moderate risk of bias according to the ROBINS-I tool. There were statistically significant differences between the pretreatment and posttreatment arches. The average expansion was significantly different from that predicted for each type of tooth in both the maxilla and mandible. Furthermore, the efficiency decreased from the anterior area to the posterior area in the upper arch.ConclusionDespite the fact that arch expansion with Invisalign® is not entirely predictable, clear aligner treatment is a viable option for addressing dentition crowding. The efficacy of expansion is greatest in the premolar area. More research focusing on treatment outcomes with different materials of aligners should be conducted in the future. Overcorrection should be considered when planning arch expansion with Invisalign. In the maxilla, the expansion rate decreases from the anterior to the posterior, and presetting sufficient buccal root torque of posterior teeth may result in improved efficiency of expansion.

Optimization Analysis of Two-Factor Continuous Variable between Thread Depth and Pitch of Microimplant under Toque Force.

Microimplant, an anchorage device, is widely applied in clinical orthodontic treatment. Since tooth torque is required to be controlled during orthodontic tooth movement, a novel microimplant needs to be developed to apply better torque force during orthodontic. In this study, the optimal value ranges of thread depth and pitch under toque force were studied for choosing microimplant with relevant value ranges in clinical design from biomechanical perspective. Finite element analysis (FEA) and optimization design technology were used for accessing the optimal value ranges of thread depth and pitch under toque force. Thread depth (D) (0.1 mm to 0.4 mm) and pitch (P) (0.4 mm to 1 mm) were used as continuous variables, with the other parameters as constant, and the optimal value ranges were obtained by analyzing the tangent slope and sensitivity of the response curve. When a torque force of 6 Nmm was applied on the microimplant, the maximum equivalent stress (Max EQV) of cortical bone and maximum displacements (Max DM) of microimplant were analysis indexes. When 0.55 mm ≤ P ≤ 1 mm, the Max EQV of cortical bone was relatively smaller with less variation range. When 0.1 mm ≤ D ≤ 0.35 mm, the Max DM of microimplant was relatively smaller with less variation range. So in conclusion, the initial stability of microimplants with pitch 0.55 mm ≤ P ≤ 1 mm and thread depth 0.1 mm ≤ D ≤ 0.35 mm was better with the torque force applied.

A Three-Dimensional Finite Element Analysis: Maxillary Dentition Distalization with the Aid of Microimplant in Lingual Orthodontics.

AimTo analyze the movement of anterior teeth by changing the height of the power-arm and changing the force application points during whole maxillary dentition distalization with the aid of micro-implants in lingual orthodontics to set a biomechanical reference for effective clinical use of lingual orthodontic appliance.MethodsA three-dimensional finite element model of the maxillary teeth with lingual appliance and the associated support tissue was established. Maxillary dentition with the force of 200g was distalized using implant as anchorage, then the movement of anterior teeth was analyzed by changing the length of power-arm (1mm, 3mm, 6mm, 9mm) and by changing the force location from lingual side to buccal side.ResultsDuring whole maxillary dentition distalization with aid of the implants in lingual orthodontics: when the height of power arm was 1mm, the anterior teeth rotated clockwise, with the increasing of the height of power-arm, the anterior teeth rotated counterclockwise gradually. When the height of power-arm was 9mm, all anterior teeth rotated counterclockwise. Central incisor and lateral incisor rotated counterclockwise and canine rotated clockwise when the buccal side force was applied.ConclusionWith the increase of the height of the power-arm, the movement pattern of the upper anterior teeth is different. The canine is more sensitive to the height of the power-arm than the central incisor and the lateral incisor. When the height of the power-arm reaches 9mm, the upper anterior teeth are displayed as crown tipping buccally movement. Compare with lingual side force, the buccal side force do better in preventing the loss of anterior tooth torque. If the upper anterior teeth are up-right or lingually tipped before treatment, it is preferable to use longer power-arm or buccal side traction force. If the anterior teeth are already tipped buccally, then short power-arm or lingual side force is advised.

Inclinometer: A new device for measuring intermolar torque and angle.

The torque of posterior teeth is of great importance in esthetics and occlusion. In the present article, we introduce a simple but useful device to measure intermolar torque. The device consists of two movable and adjustable arms that lie on the selected molar teeth bilaterally; the graduated plane at the body of the appliance then shows the intermolar torque. This device can measure intermolar torque easily and rapidly, with high validity and at a low cost.

Assessment of Maxillary Expansion by Piezocision-Assisted Orthodontics: A Pilot Study.

The correction of transverse malocclusions due to maxillary width deficiency in adults is challenging. Multiple surgical and nonsurgical procedures have been used in conjunction with orthodontics to address this situation, and most common is the surgically assisted rapid maxillary expansion (SA-RME). Although successful, it is quite aggressive. The present investigation assesses the usefulness of Piezocision-assisted orthodontics as a less-invasive option for treatment of transverse maxillary deficiencies in adults. Dental casts were taken before and after Piezocision-assisted palatal expansion in four patients. They were digitized into STL files and superimposed. Differences on cross-arch tooth torque, angulation/tipping, and movement distances between time points were quantified using a digital static and a novel digital 3D-movement evaluation method. For the buccolingual movement per tooth, first premolars averaged 3.33 ± 1.3 mm, second premolars averaged 3.63 ± 0.6 mm, and first and second molars averaged 1.56 ± 1.2 mm and 0.36 ± 1.2 mm, respectively. Bodily movement of the teeth was observed with minimal tipping and no development of gingival recessions. Piezocision-assisted palatal expansion is a safe and reliable procedure that can help patients with maxillary width deficiency. It is a new tool in the orthodontist's armamentarium that can be used as an accelerator of treatment and as a new way to solve orthodontic challenges in selected adult patients.

Estimation and comparative evaluation of tip and torque values of Saudis for bracket prescription

ObjectivesThe present study aimed at determining the tip and torque values of the teeth of Saudi adults with normal occlusion to develop orthodontic bracket prescription. In addition, we proposed to compare the results with published data of varied geographical distribution. Materials and MethodsThe study sample consisted of 60 upper and lower study models of Saudi adults (30 males and 30 females) with normal occlusion and a balanced facial profile. Evaluated by experts, the torque and tip of teeth were measured using a torque angulation device. The collected data was analyzed using SPSS (IBM SPSS Inc., version 20, Chicago, IL, USA). The mean, and standard deviation were obtained for each measurement. Paired t-test, Independent t-test and student t-test were used for the comparison at a significant level of (p ≤ 0.05). ResultThe results of torque and tip of teeth for the Saudi adult population showed no significant differences between the right and the left quadrants of the analyzed study sample. In general, there was no significant observed difference between male and female samples, accordingly, the Saudi tip and torque data were combined. However, the comparisons of the combined Saudi data to the published data showed significant differences (p ≤ 0.05). ConclusionStatistically Significant differences were found between the combined Saudi data when compared to North American, Italian, African, Japanese, and Indian data. We inferred, that racial differences should be considered when presenting bracket prescriptions.

A phenomenological model for chain transmissions efficiency

This work deals with the development of a simplified and time-efficient phenomenological model for chain transmissions efficiency. Firstly, a complete multibody model for a final transmission of a motorcycle is developed in MSC Adams View environment, and is properly validated in terms of efficiency with experimental tests on a real chain system. Results from multibody simulations are used to develop a new analytical model, that relates all the main operating and geometry parameters of the transmission system to the transmission efficiency with simple relations. In particular, the influence of the polygonal effect on system efficiency is investigated, finding a relationship with the angle of the sprockets pitch polygon.A new parameter, called chain tension efficiency, is introduced to model the distribution of losses within the system. A linear relationship between this parameter and the number of sprockets teeth and with the system efficiency was assumed and validated, with good results. In addition, the dependence of slack span tension from several parameters, like speed, torque and number of teeth of sprockets, is investigated. In particular, it is highly dependent on the chain peripheral speed, both for a centrifugal tension and for a further linear component of tension, which might be originated by friction between links.The presented simple model can describe the chain system dynamics with low computational effort, allowing the designer to use a smart tool to select the proper transmission parameters. Due to its computational efficiency, the model is also useful for real-time and hardware-in-the-loop simulations.

Assessment of dental arches expansion using ligature and passive self-ligating braces in combination with Pitts broad arches and early elastics

Was to analyze the effectiveness of the use of Pitts Broad and early elastics in the treatment of patients with narrowing and deformation in dentition. The results of orthodontic treatment of 46 adult patients with narrowing and deformation in dentition are presented. Patients were separated in 2 groups, depending on the algorithm of treatment: group 1 - using the braces of passive self-ligation, Pitts Broad and early short elastics; group 2 - using ligature braces and archwires Orthos. Biometric analysis of the diagnostic models of the 1st group after treatment showed a significant increase in the area of the premolars on the upper (between premolars - 39.8±0.4 mm, between molars - 48.3±0.5 mm) and lower (between premolars - 37.1±0.5 mm, between molars - 46.3±0.6 mm) jaws compared to the data before treatment. Biometric analysis of the diagnostic models of the 2d group showed that expansion in the area of the molars was achieved in a much smaller volume in the upper and lower jaws, compared with the 1st group (upper jaw: between premolars - 35.7±0.4 mm, between molars - 43.5±0.5 mm; lower jaw: between premolars - 33.2±0.3 mm, between molars - 42.3±0.5 mm). The passive self-ligation system in combination with protocol of Pitts Broad already contributes the expansion of dentition in aesthetically significant areas (distal regions) in the early stages of treatment. Using of early light elastics provides an early control of the lateral tooth torque, which allows achieving a harmonious and wide smile at the end of treatment.

The effect of varying head tilt on the perceived color from composite resin and porcelain restorations: Simulating the effect of altering torque

This study aimed to assess the effect of changes in tooth torque on the perceived color of composite and porcelain restorations. A total of 30 patients with previous composite restorations and 30 patients with porcelain restorations on lateral and central incisors were selected. To simulate the effect of dental torque change, we asked the patients to tilt their heads upwards and downwards to represent buccal and palatal crown torque, respectively. Photographs were taken in 3 different positions (natural head position, 15° upward tilt, and 15° downward tilt). A laser alignment tool was used to help with head positioning. Color was measured on the 3 principal axes of the Commission Internationale de L'Eclairage, L∗, a∗, and b∗ color space using Photoshop software (Adobe, San Jose, Calif), and color differences were calculated. The midpoint of the clinical crown, both mesiodistally and incisogingival, was selected as the point of measurement. A general linear model was used to analyze the significance of changes in each value of different tooth torques. A t test was used to compare color changes of 2 different incisors (central and lateral) and overall color differences in the 2 types of restoration. Significant changes of the L∗ and a∗ values were found as a result of the change in head inclination, whereas b∗ values remained unchanged. It was found that buccal crown torque resulted in lighter and greener porcelain restorations. Composite restorations behaved similarly with the only difference being that the central incisors appeared bluer. Palatal crown torque resulted in a darker and redder porcelain restoration and a darker, redder, and yellower composite restoration. No significant differences were found between color changes in the central and lateral incisors. Furthermore, porcelain and composite restorations had similar color changes with alteration of head inclination. Orthodontic changes of tooth torque alter the color perceived from composite and porcelain restorations.

The electric machine with two-sided stator, axial magnetic flux, permanent magnets and multilayered printing windings

The use of printed windings in electric machines with permanent magnets and axial magnetic flux allows to reduce their axial size and significantly increase the current density in the windings due to the small thickness and correspondingly large width of the conductors of the printed winding and, as a result, their better cooling. The dependences of voltage and power in the generator mode are determined when connecting the windings through the diode bridge to the load. Investigations of the effect of stator teeth on the magnitude of the electromagnetic torque are made. It was found that the presence of teeth on the stator allows you to increase the electromagnetic torque of the electric machine by about 26% compared with the version of the magnetic system without teeth. The effect of the displacement of one stator relative to another on the magnitude of the tooth torque has been studied. A prototype of an electric machine with a double-sided stator, multilayer printed windings and permanent cylindrical magnets was manufactured. The calculated model of the generator adequately describes the physical model. The discrepancy between the calculated and experimental values does not exceed ε = 4%. The characteristics of the studied generators were calculated by the software packages Simcenter MagNet and Simcenter MotorSolve.

Effect of orthodontic tooth movement on keratinized gingival width

OBJECTIVE The relationship between the orthodontic tooth movement and the change of keratinized gingival width was analyzed by measuring the keratinized gingival width and position of the teeth before and after 28 orthodontic treatments. METHODS The photos were matched to the model and the width of the keratinized gingival was obtained by measuring the length of the crown, and the keratinized gingiva. The pre- and post-treatment models were overlapped on rapidform 2006 and the change of tooth position before and after orthodontic movement could be accurately measured, and the relationship between tooth intrusion and extrusion, retraction and forward movement, torque variation and keratinized gingival width was statistically investigated. RESULTS Analysis of the correlation between data before and after treatments for 213 teeth in 28 patients revealed a strong correlation between changes in tooth torque angle and changes in keratinized gingiva width (r=-0.47, P 0.05). Regression coefficient was negatively relative to the reference incisor between the teeth for the canines and premolars (canine regression coefficient=-0.35, premolar regression coefficient=-0.38, P<0.05). Therefore, the study found that there was a strong negative correlation between the changes in tooth torque angle and width of keratinized gingival (r=-0.41, P<0.001), that is, an increase in positive torque led to the reduction of width of keratinized gingiva, and on the contrary the increase of negative torque would cause the width of keratinized gingiva increase. There was no significant correlation between the intrusion and extrusion of the teeth for the width of keratinized gingiva. The sensitivity of different teeth for the width of keratinized gingiva differed, with incisor compared with canines and premolars that were more prone to keratinized gingiva width changes. CONCLUSION Tooth movement during orthodontics affected the width of the keratinized gingiva width, and the increase in positive torque was more likely to cause a reduction in the width of keratinized gingiva. There was no significant correlation between the intrusion and retraction of the teeth and the change in the width of keratinized gingiva. Incisors were more prone to changes in the width of keratinized gingiva relative to the cuspids and premolars during tooth movement. In the orthodontic process, it is possible to predict the effect of changes in the position of the teeth on the keratinized gingiva width, and attention shoud be to the changes in the keratinized gingiva width.

Efficiency of upper arch expansion with the Invisalign system.

To investigate the efficiency and movement pattern of upper arch expansion using Invisalign aligners. The correlation between the amount of designed expansion and the efficiency of bodily expansion was evaluated, as were the initial molar torque and efficiency of bodily expansion. Twenty Chinese adult patients who underwent arch expansion with Invisalign aligners were included in this study. Records of pretreatment (T0 stage) and immediately after completing the expansion phase (T1 stage) were collected, including digital models and cone-beam computed tomography. Dolphin 3D, Geomagic Studio 12.0, and Meazure software were employed to measure data and calculate differences between the expected and actual outcomes. There were significant differences between the expected and actual expansion amounts (P< .05). The average expansion efficiencies of the upper canine crown, first premolar crown, second premolar crown, and first molar crown were 79.75 ± 15.23%, 76.1 ± 18.32%, 73.27 ± 19.91%, and 68.31 ± 24.41%, respectively. The average efficiency of bodily expansion movement for the maxillary first molar was 36.35 ± 29.32%. Negative correlations were found between preset expansion amounts and the efficiency of bodily expansion movement (P < .05), and between initial maxillary first molar torque and efficiency of bodily expansion movement (P < .05). Aligners could increase the arch width, but expansion was achieved by tipping movement. The evaluation of initial position and preset of sufficient root-buccal torque of posterior teeth were necessary due to the lower efficiency of bodily buccal expansion by the Invisalign system.

A novel approach of torque control for maxillary displaced incisors

Effective torque control is crucial for the successful treatment of impacted incisors; however, torque control is often a challenge with the use of conventional bracket systems, especially when the adjacent teeth require opposite torque managements. A novel approach of torque control for adjacent anterior teeth is introduced in this case report. A 12-year-old boy had an impacted maxillary right central incisor with the adjacent teeth severely displaced. The treatment plan was to regain space and pull the impacted incisor into the dentition. An upper removable appliance was first used to regain space for the impacted central incisor, followed by a spontaneous eruption of the impacted incisor. Subsequently, fixed appliances were bonded to level and align the dentition. However, the crown of the maxillary right central incisor was found to be tipped lingually, while the maxillary right lateral incisor was tipped labially. Traditional torque control, including torque bend and the use of a Warren spring, were first used for the correction, but they were ineffective due to the overlap of the root apex of the maxillary central incisor and lateral incisor. After the roots were separated with a V-shaped curve, auxiliary brackets were bonded on the gingival one-third areas of the maxillary incisors and canine with nickel-titanium wires used for the torque control. This approach of using the auxiliary brackets and wires was demonstrated to be efficient and effective in the torque control of adjacent anterior teeth with opposite torque control requirements. The final result and the 2-year follow-up records demonstrated the proper torque of anterior teeth and good and stable dental and profile esthetics.

MODERN APPROACHES TO THE DETERMINATION OF THE ANGLE OF TEETH INCLINATION IN THE DIAGNOSIS AND PLANNING OF ORTHODONTIC TREATMENT

Aim. To conduct a comparative analysis of existing methods for measuring the angles of inclination of tooth and determining the torque of teeth with orthognathic occlusion. Materials and methods. Inclination angles were measured in 137 patients with physiological occlusion and the standard values of the torques of permanent teeth. Four methods of investigation were used to measure tooth torques. In the first method, the angle of the inclination formed by the occlusal plane and the conditional middle vertical of the tooth was measured by the protractor on the incisions of the plaster models of the dentition rows. The second method, which allows evaluating torques and teeth angulation at the same time, was carried out with the aid of the «Arco-zet» apparatus of «Scheu Dental GmbH». As the third method of research, the technique of analyzing images of cone-beam computed tomography was used, on which linear and angular reference points were applied. The fourth method of investigation was based on the results of scanning gypsum models with a laser scanner with the subsequent creation of a digital three-dimensional image and the formation of a virtual Set-Up model in the file 3Txer 2.5.0. Results. All methods of measuring the angles of teeth in the vestibular-lingual direction can be applied both in the applied and in the clinical aspect. Determining the torques of permanent teeth using the morphometry of gypsum models of dentition and instrumentation method is characterized by laboriousness, length of studies, and also the presence of errors in measurements. Methods for analyzing images of cone-beam computed tomography and using the virtual diagnostic SetUp model in the ORAPIX file 3Txer 2.5.0 are high-tech, precise, and reproducibility and interpretation of the results allows using the available angular and linear parameters for assessing the effectiveness of conducted orthodontic activities at all stages of treatment. Conclusion. The introduction into clinical orthodontics derived from research boundaries reference values and confidence intervals inclination angles of the upper teeth, the lower jaw, as well as tilt incline of teeth of antagonists will reduce the time required for the early stage diagnosis and increase the effectiveness of the test results of orthodontic treatment. Improvement of existing methods of diagnosis of dentoalveolar anomalies has led to the creation of high-tech, precision, computerized measurement methods, the introduction of which will allow not only minimizing errors associated with instrumental measurement techniques in the structures of the maxillofacial region, but, due to the predictability of orthodontic treatment, achieving optimal functional – aesthetic results.

Movement of anterior teeth using clear aligners: a three-dimensional, retrospective evaluation

BackgroundClear aligner treatment offers several advantages, but the available literature shows that some kind of tooth movements are unpredictable. In addition, the majority of the studies are focused on one clear aligner system, while different characteristics of various systems can provide different treatment outcomes. The aim of the present retrospective cohort study was to evaluate the predictability of Nuvola® aligner system in achieving torque movements of anterior teeth.MethodsThirty-nine adult patients, who were consecutively treated with clear aligners, were retrospectively selected, and digital models pre-treatment (T0), post-treatment (T1) and the digital setup models (TS) were collected. Only the first phase of treatment made of 12 aligners was considered for the present study. Torque of anterior teeth was measured as labiolingual inclination on digital models at T0, T1, and TS using VAM software. Any difference between the predicted and achieved torque movements was evaluated using Wilcoxon signed-rank test or paired sample t test. First-type error was set as p < 0.008.ResultsNo statistically significant difference was found for all the anterior teeth between predicted and achieved torque movements.ConclusionsThe studied clear aligner system was able to produce clinical outcomes comparable to the planning of the digital setup relative to torque movements of the anterior teeth.