Validation of finite-element-simulated orthodontic forces produced by thermoplastic aligners: Effect of aligner geometry and creep.

Purpose: Finite element (FE) models for determining the orthodontic forces delivered by clear aligners often lack validation. The aim of this study was to develop and validate accurate FE models for clear aligners, considering the small but important geometrical variations from the thermoforming process and the creep behavior of the aligner material.

Methods And Materials: The tooth misalignment considered was a 2.

Assessment of orthodontic treatment efficacy of Clarity Aligners using the Peer Assessment Rating index and the American Board of Orthodontics Cast-Radiograph Evaluation.

Introduction: 3M Oral Care Solutions (St Paul, Minn) has recently introduced Clarity Aligners into the market. This cohort study evaluated the orthodontic treatment efficacy of this clear aligner system using the Peer Assessment Rating (PAR) index and the American Board of Orthodontics Cast-Radiograph Evaluation (CR-Eval).

Methods: Pretreatment and posttreatment dental models of 87 subjects who had undergone orthodontic treatment using Clarity Aligners in both arches to align their teeth to a target setup were independently evaluated by 4 examiners using the PAR index and the American Board of Orthodontics CR-Eval.

Validation of finite element models for orthodontic aligners.

Purpose: Clear thermoplastic aligners have become popular in orthodontics, but the biomechanics of these devices is not well understood. Neither is the tooth movement induced by such devices. The aim of this study was to develop and validate finite element (FE) models for clear thermoplastic teeth aligners for orthodontic force prediction.

Three-dimensional cone-beam computed technology evaluation of skeletal and dental changes in growing patients with Class II malocclusion treated with the cervical pull face-bow headgear appliance.

Introduction: This study aimed to 3-dimensionally quantify and compare the outcomes of growing patients with Class II malocclusion treated with the cervical pull face-bow headgear appliance in combination with full fixed orthodontic appliances.

Methods: The study sample consisted of 22 patients with Class II malocclusion with the following inclusion criteria: ANB >4.75°, Class II molar relationship, and SN-GoGn <37°.

Orbital volume changes during growth and development in human children assessed using cone beam computed tomography.

Objectives: To measure growth-related changes in orbital volume from childhood to the late teenage years using cone-beam computed tomography (CBCT) scans.

Methods: This retrospective cohort study involved 65 (24 male, 41 female) healthy Caucasian children (ages 6-18 years) with existing serial craniofacial CBCT scans. CBCT scans were available for 292 orbits.

Evaluation of transverse maxillary growth on cone-beam computed tomography images.

This study aimed at quantifying the annual transverse growth of the maxilla using skeletal landmarks in three different regions on cone-beam computed tomography (CBCT) scans. CBCT scans taken before and after orthodontic treatment of 100 child and adolescent patients (50 male, 50 female) without maxillary transverse deficiencies were used to determine the transverse linear distances between the greater palatine foramina (GPFd), the lateral walls of the nasal cavity (NCd), and the infraorbital foramina (IOFd). We found that all distances increased significantly with growth in both genders (p < 0.

Midpalatal suture density ratio: Assessing the predictive power of a novel predictor of skeletal response to maxillary expansion.

Introduction: Rapid maxillary expansion (RME) is a common orthodontic treatment to correct maxillary transverse deficiency; however, the inability to determine the precise timing of fusion of the midpalatal suture creates difficulty for clinicians to prescribe the appropriate treatment, surgical or nonsurgical expansion. The purpose of this study was to assess the predictive power of the midpalatal suture density ratio (MPSD) for a skeletal response to RME.

Methods: Pre- and posttreatment cone-beam computed tomography scans were obtained from 78 orthodontic patients aged from 8 to 18 years treated with RME.

Three-dimensional condylar changes from Herbst appliance and multibracket treatment: A comparison with matched Class II elastics.

Introduction: The purpose of this study was to quantify and qualify the 3-dimensional (3D) condylar changes using mandibular 3D regional superimposition techniques in adolescent patients with Class II Division 1 malocclusions treated with either a 2-phase or single-phase approach.

Methods: Twenty patients with Herbst appliances who met the inclusion criteria and had cone-beam computed tomography (CBCT) images taken before, 8 weeks after Herbst removal, and after the completion of multibracket appliance treatment constituted the Herbst group. They were compared with 11 subjects with Class II malocclusion who were treated with elastics and multibracket appliances and who had CBCT images taken before and after treatment.

Changes in maximum lip-closing force after extraction and nonextraction orthodontic treatments.

Objective: The aims of the present study were to evaluate the changes in the maximum lip-closing force (MLF) after orthodontic treatment with or without premolar extractions and verify the correlation of these changes with dentoskeletal changes.

Methods: In total, 17 women who underwent nonextraction orthodontic treatment and 15 women who underwent orthodontic treatment with extraction of all four first premolars were included in this retrospective study. For all patients, lateral cephalograms and dental models were measured before (T0) and after (T1) treatment.

Comparative assessment of bonding time and 1-year bracket survival using flash-free and conventional adhesives for orthodontic bracket bonding: A split-mouth randomized controlled clinical trial.

Introduction: A new flash-free adhesive promises to eliminate the flash removal step in bonding and to reduce bonding time by as much as 40% per bracket, with a bond failure rate of less than 2%. The aim of this trial was to compare bonding time and bracket failure rate over a 1-year period between the flash-free adhesive and a conventional adhesive for orthodontic bracket bonding.

Methods: Forty-five consecutive patients had their maxillary incisors, canines, and premolars bonded with ceramic brackets (Clarity Advanced; 3M Unitek, Monrovia, Calif) using a flash-free adhesive (APC Flash-Free Adhesive Appliance System; 3M Unitek) on 1 side and a conventional adhesive (APCII Adhesive Appliance System; 3M Unitek) on the other side.

A comparative assessment of bracket survival and adhesive removal time using flash-free or conventional adhesive for orthodontic bracket bonding: A split-mouth randomized controlled clinical trial.

Objectives: To compare bracket survival and adhesive removal time between a flash-free and a conventional adhesive for orthodontic bracket bonding.

Materials And Methods: Forty-five consecutive patients had their maxillary incisors, canines, and premolars bonded with ceramic brackets using a flash-free adhesive (APC Flash-Free Adhesive, 3M Unitek, Monrovia, Calif) on one side and a conventional adhesive (APCII Adhesive, 3M Unitek) on the other side. The side allocation was randomized.

Alternative cone-beam computed tomography method for the analysis of bone density around impacted maxillary canines.

Introduction: Genetic and environmental etiologic factors have been described for maxillary canine impaction, except for the trabecular bone characteristics in the impacted area. The aim of this study was to evaluate the surface area and fractal dimension of the alveolar bone on cone-beam computed tomography (CBCT) images of patients with maxillary impacted canines.

Methods: The sample comprised preorthodontic treatment CBCT images of 49 participants with maxillary impacted canines (31 unilateral and 18 bilateral).

How accurate is Invisalign in nonextraction cases? Are predicted tooth positions achieved?

Objective: To evaluate the accuracy of Invisalign technology in achieving predicted tooth positions with respect to tooth type and direction of tooth movement.

Materials And Methods: The posttreatment models of 30 patients who had nonextraction Invisalign treatment were digitally superimposed on their corresponding virtual treatment plan models using best-fit surface-based registration. The differences between actual treatment outcome and predicted outcome were computed and tested for statistical significance for each tooth type in mesial-distal, facial-lingual, and occlusal-gingival directions, as well as for tip, torque, and rotation.

Comparing Stability of Mandibular Setback Versus 2-Jaw Surgery in Class III Patients With Minimal Presurgical Orthodontics.

Purpose: The aim of this study was to compare treatment time and skeletal stability between mandibular setback surgery (MS) and 2-jaw surgery (2J) with minimal presurgical orthodontics (MPO) in patients with skeletal Class III.

Materials And Methods: One hundred ninety-five patients who underwent orthognathic surgery were enrolled in this retrospective cohort study. Consecutive patients were selected based on standardized inclusion criteria: Class III malocclusion with mandibular prognathism, surgery type, and presurgical orthodontics with non-extraction for less than 6 months (MPO).

Comparative evaluation of the sliding plate technique for fixation of a sagittal split ramus osteotomy: finite element analysis.

Objective: This study evaluated the stress distribution of the sliding plate (SP) and conventional miniplate (CM) fixation techniques of a sagittal split ramus osteotomy (SSRO) using 3-dimensional (3-D) finite element analysis.

Study Design: Four 3-D finite element models according to the number and shape of screw holes in the plate were simulated, and the von Mises stress was analyzed: SP with 2 round and 2 oval holes (SP-2 R2 O), SP with 2 round and 1 oval holes (SP-2 R1 O), CM with 4 round holes (CM-4 R), and CM with 3 round holes (CM-3 R).

Results: The fixation technique with CM-4 R showed a better stress distribution than CM-3 R, which in turn showed better results compared to the 2 different SPs.

Midpalatal suture density ratio: A novel predictor of skeletal response to rapid maxillary expansion.

Introduction: During adolescence, increasing interdigitation of the midpalatal suture increases resistance to rapid maxillary expansion (RME); this decreases its skeletal effect. In this study, we aimed at determining whether a novel measure of midpalatal suture maturity, the midpalatal suture density ratio, can be used as a valid predictor of the skeletal response to RME.

Methods: The midpalatal suture density ratio, chronologic age, cervical vertebral maturation, and the stage of midpalatal suture maturation were assessed before treatment for 30 patients (ages, 12.

The effect of root and bone visualization on perceptions of the quality of orthodontic treatment simulations.

Objective: To evaluate the effect of root and bone visibility on orthodontists' perceptions of the quality of treatment simulations.

Material And Methods: An online survey was used to present orthodontists with setups generated for 10 patients in two different types of view: with and without bone and roots as modeled from a cone-beam computed tomography (CBCT) scan. The orthodontists were asked to rate the quality of the setups from poor to ideal on a 100-point visual analog scale and, if applicable, to identify features of concern that led them to giving a setup a less-than-ideal rating.

Conservative interdisciplinary treatment of a case with multiple facial and condyle fractures.

The purpose of this case report is to describe an interdisciplinary approach for a 51-year-old male who underwent multiple facial fractures including bilateral condyle fractures. The patient underwent emergency surgery, which included open reduction of the maxilla and mandibular symphysis and closed reduction of the bilateral condyle fractures. Although the patient recovered a comfortable range of mouth opening and alleviation of the temporomandibular joint (TMJ) symptoms after surgery, he suffered from a large anterior-posterior discrepancy due to less stability on the condyle-fossa relationships and from open bite with contacts only on both second molars and right second premolars.

Comparison of the Stability After Mandibular Setback With Minimal Orthodontics of Class III Patients With Different Facial Types.

Purpose: Most studies on the surgery-first approach focused on skeletal relapse compared with conventional surgery. The objective of this study was to compare the stability of skeletal Class III patients with 2 different vertical facial types after mandibular setback surgery (MS) with minimal orthodontic preparation (MO).

Materials And Methods: In this retrospective study, the patients were recruited from a population that had undergone MS.

Evaluation of Soft Tissue Changes Around the Lips After Mandibular Setback Surgery With Minimal Orthodontics Using Three-Dimensional Stereophotogrammetry.

Purpose: Most reports on the surgery-first approach in skeletal Class III malocclusion have focused on the skeletal changes. The present study evaluated the soft tissue changes around the lips over time after mandibular setback surgery (MS) with minimal orthodontics (MO) using 3-dimensional (3D) stereophotogrammetry.

Materials And Methods: We performed a retrospective study of patients with mandibular prognathism who had undergone MS-MO.

Transfer accuracy of vinyl polysiloxane trays for indirect bonding.

Objective: To elicit the magnitude, directional bias, and frequency of bracket positioning errors caused by the transfer of brackets from a dental cast to the patient's dentition in a clinical setting.

Materials And Methods: A total of 136 brackets were evaluated. The brackets were placed on dental casts and scanned using cone beam computed tomography (CBCT) to capture 3-D positioning data.