Abstract: OBJECTIVES To compare skeletal and dentoalveolar changes of miniscrew-assisted rapid palatal expansion (MARPE) according to the length of the miniscrews. MATERIALS AND METHODS This two-arm parallel-randomized controlled trial included 32 adult patients aged 19-35 years who received orthodontic treatment with MARPE. Patients were allocated to two groups, group long (L) and short (S), through block randomization according to the length of the miniscrews installed in MARPE. Cone-beam computed tomography was performed before expansion and after removal of the MARPE; superimposition of the images was conducted. The primary outcome included the amount of bone expansion and the change in the inclination of the anchorage teeth. The secondary outcome included the success rate of midpalatal suture opening and stability of the miniscrews. Blinding was performed during outcome assessment. RESULTS The final sample comprised 31 patients. There was no significant difference in patient characteristics between group L (n = 16) and group S (n = 15). The change in the width of the processus zygomaticus (P = .010) and ectocanine (P = .001) was significantly higher in group L. A significantly higher success rate of the posterior miniscrews was seen in group L (P = .024). There was no statistically significant difference in the success rate of suture separation or change in tooth inclination. Notable complications were not reported. CONCLUSIONS MARPE with longer miniscrews can increase the amount of expansion of the maxillary basal bone and canine alveolar bone. Although it also aided in miniscrew stability, it did not guarantee successful midpalatal suture separation.

Abstract: OBJECTIVES To quantify the predicted occlusal contact outcomes compared with the clinically achieved occlusal contacts following treatment using the Invisalign aligner appliance. MATERIALS AND METHODS The occlusal contacts of 33 adult patients presenting with a Class I mild-to-moderate malocclusion (spacing <4 mm or crowding of <6 mm) and treated using the Invisalign appliance were measured at the initial, predicted, and achieved stages of treatment by the metrology software Geomagic Control X. Assessed measurements were related to individual teeth and anterior, posterior, and overall contacts. RESULTS The mean (standard deviation) difference between the achieved occlusal contact was significantly less than that predicted for overall occlusal contact and posterior occlusal contact (P < .0025). The achieved posterior occlusal contact was also less than pretreatment initial posterior occlusal contact. There was no difference in anterior occlusal contact between the predicted and achieved outcomes (P > .05). The central and lateral incisors displayed no statistically significant difference between the predicted and achieved occlusal contact. The patients with prescribed overcorrection demonstrated a statistically significant difference in predicted occlusal contact compared with those with nonprescribed overcorrection (P ≤ .0025), but no statistically significant difference in achieved occlusal contact. CONCLUSIONS Treatment by the Invisalign appliance in Class I mild-to-moderate malocclusion resulted in a decrease in posterior occlusal contact. Further research is required to account for the deficiencies between the predicted and achieved clinical outcome related to occlusal contact and to determine the corrective changes required in the treatment protocols.

Abstract: OBJECTIVES To investigate the changes made by orthodontists to the initial digital treatment plan (DTP) regarding the Invisalign appliance provided by Align Technology until acceptance of the plan by the orthodontist. MATERIALS AND METHODS The DTPs of subjects who underwent treatment with the Invisalign appliance and satisfied inclusion criteria were assessed to determine the number of DTPs and changes regarding prescription of aligners, composite resin (CR) attachments, and interproximal reduction (IPR) between the initial DTP and the accepted plan. Statistical analyses were calculated via GraphPad Prism 9.0 (GraphPad Software Inc., La Jolla, Calif). RESULTS Most of the 431 subjects who satisfied inclusion/exclusion criteria were female (72.85%). More DTPs were required for subjects who had orthodontic extractions (median [interquartile range; IQR]: 4 [3, 5]) compared with those who did not (median [IQR]: 3 [2, 4], P < .0001). The median (IQR) overall number of aligners prescribed in the accepted DTP (30 [20, 39]) was greater than the initial DTP (30 [22,41], P < .001). The number of teeth used for CR attachments increased from the initial to the accepted DTP (P < .001). More CR attachments were observed in extraction treatment DTPs with a prescribed 2-week aligner change protocol compared with nonextraction treatment (P < .0001). The number of contact points with prescribed IPR increased between initial and accepted DTPs (P < .0001). CONCLUSIONS Significant changes regarding DTP protocols were observed between the initial and accepted DTPs and between nonextraction and extraction-based CAT.

Abstract: OBJECTIVES To compare mandibular relative anchorage loss (RAL) under reciprocal anchorage between first and second premolar extraction cases in bimaxillary protrusion mild crowding cases treated using clear aligner therapy (CAT). MATERIALS AND METHODS Adult patients who met the following criteria were included: treated using CAT with bilateral mandibular premolar extractions and space closure using intra-arch reciprocal anchorage. RAL was defined as the percent molar mesial movement relative to the sum of molar mesial plus canine distal movement. Movements of the mandibular central incisor (L1), canine (L3), and first molar (L6) were measured based on superimposition of the pre- and post-treatment dentition and jaw models. RESULTS Among the 60 mandibular extraction quadrants, 38 had lower first premolar (L4) and 22 had lower second premolar (L5) extracted. L6 mesial movement was 2.01 ± 1.11 mm with RAL of 25% in the L4 extraction group vs 3.25 ± 1.19 mm with RAL of 40% in the L5 extraction group (P < .001). Tooth movement efficacy was 43% for L1 occlusogingival movement, 75% for L1 buccolingual inclination, 60% for L3 occlusogingival movement, and 53% for L3 mesiodistal angulation. L1 had unwanted extrusion and lingual crown torquing whereas L3 had unwanted extrusion and distal crown tipping, on which the power ridges or attachments had little preventive effect. CONCLUSIONS The average mandibular reciprocal RAL is 25% or 40% for extraction of L4 or L5, respectively, in CAT cases. A RAL-based treatment planning workflow is proposed for CAT extraction cases.

Abstract: OBJECTIVES To determine the expansion rebound deformation (ERD) of clear aligners (CAs) and its biomechanical influence. MATERIALS AND METHODS A four-premolar extraction treatment plan was carried out for a patient with 2 CA companies. Thirty-six digitally scanned clear aligners with the corresponding 36 virtually constructed "ideal" aligners were constructed. The arch width and length between pairs of reference landmarks of the scanned CAs and corresponding dentition models were measured. Cone-beam computed tomography data and digital dental models were used for three-dimensional (3D) finite element analysis (FEA) modeling. Thirty-six scanned CA models with the corresponding 36 ideal CA models were constructed. One-way analysis of variance was used to determine the differences among deviation values at tooth level, and paired t-test was used to compare the displacements of teeth between the two group of CAs. RESULTS All CAs were wider and shorter than the digital model from which they were constructed. In the scanned CA model group, significant stress was observed in the buccolingual area of the periodontal ligament on posterior teeth, and the corresponding displacements of teeth were also noted. Significantly larger coronal displacements were noted for the lateral incisor, the canine, the second premolar, and the first molar in the scanned CA group (P < .05). CONCLUSIONS The general trend of ERD of thermoformed CAs was shown. This deformation may cause unforeseen tooth movements and negatively affect treatment outcomes.

Abstract: OBJECTIVES To analyze the effects of maxillary tooth distalization by clear aligner (CA) treatment with variations in the angular direction of the distalization force, presence of attachments, and force-application method used. MATERIALS AND METHODS A finite element model containing alveolar bone, dentition, and periodontal ligament was constructed. Analytical model groups were as follows: (1) distalization with buttons (without attachments), (2) buttons on canines (with attachments), (3) precision cuts on the canines (without attachments), and (4) precision cuts on the canines (with attachments). A distalization force of 1.5 N was applied to the button or precision cut at -30°, -20°, -10°, 0°, 10°, 20°, and 30° to the occlusal plane. RESULTS As the direction of force approached +30°, the dentition inclined posteriorly. The posterior movement pattern was significantly influenced by the presence of an attachment and the direction of force, rather than the area where the force was applied. Distal inclination was dramatically reduced with attachments. A disengagement or deformation of the CA may reduce the distalization efficiency of the dentition or move the dentition in an inappropriate direction. CONCLUSIONS Attachments for efficient distalization by the CA are necessary. The use of miniscrews in the direction of force parallel to the occlusal plane is more advantageous than the use of Class II elastics. Due to CA deformation, distalization with the button on the canines can be more effective for distal movement of the maxillary dentition.

Abstract: OBJECTIVES To identify and analyze the 50 most cited articles on temporary anchorage devices (TADs) and investigate the achievement and development of scientific research about the topic through a bibliometric analysis. MATERIALS AND METHODS On August 22, 2022, a computerized database search was performed to detect papers published in the scientific literature about TADs from 2012 to 2022. Metrics data were identified using the Incites Journal Citation Reports (Clarivate Analytics) data set. The Scopus database was used to obtain information on the authors' affiliations, country of origin, and h-index. Key words were automatically harvested from the selected articles to implement the visualized analysis. RESULTS From a total of 1858 papers screened by searching the database, a list of the top 50 most cited articles was created. The total number of citations collected by the 50 most cited articles in TADs was 2380. Among the 50 most cited articles on TADs, 38 were original research papers (76.0%) and 12 were reviews (24.0%). As shown by the key word-network analysis, Orthodontic anchorage procedure was identified as the larger node. CONCLUSIONS Findings of this bibliometric study showed an increasing number of citations for papers on TADs, accompanied by a simultaneous rise in scientific interest in this topic in the past decade. The present work identifies the most influential articles, emphasizing the journals, the authors, and the topics addressed.

Abstract: OBJECTIVES To clarify the effect of attachment types on bodily movement of the maxillary canine in aligner orthodontics. MATERIALS AND METHODS Using an aligner, the canine was moved bodily by 0.1 mm distally as a target position. Orthodontic tooth movement was simulated using the finite element method (FEM). The alveolar socket was displaced in the same manner as the initial movement caused by elastic deformation of the periodontal ligament. First, the initial movement was calculated, and then the alveolar socket was displaced in the same direction and with the same magnitude as the initial movement. These calculations were repeated to move the teeth after placement of the aligner. The teeth and the alveolar bone were assumed to be rigid bodies. A FEM model of the aligner was made based on the crown surfaces. The thickness of the aligner was 0.45 mm, and its Young's modulus was 2 GPa. Three types of attachments-semicircular couple, vertical rectangular, and horizontal rectangular-were placed on the canine crown. RESULTS Regardless of the type of attachment, upon placement of the aligner on the dentition the crown of the canine moved to the target position, while the apex hardly moved. That is, the canine tipped and rotated. After repeating the calculation, the canine became upright and moved bodily regardless of the attachment type. In the aligner without an attachment, the canine did not become upright. CONCLUSIONS There was almost no difference among attachment types in terms of achieving bodily movement of the canine.

Abstract: OBJECTIVES To evaluate the content, reliability, and quality of videos of patient experiences after orthognathic surgery on YouTube. MATERIALS AND METHODS Fifty videos that met the inclusion criteria were analyzed. The demographic characteristics of the videos were determined, and 13 points were used to classify poor and rich-content videos. The quality of the videos was evaluated using the Video Information and Quality Index (VIQI), Global Quality Score (GQS), and DISCERN. The Mann-Whitney U-test, Spearman correlation, and linear regression analysis were used for statistical analysis. RESULTS When poor- and rich-content videos were evaluated, there were statistically significant differences in video duration, number of likes, number of comments, and interaction index (P < .05). Compared to the poor-content video group, the GQS score, DISCERN, total content, and VIQI score of the rich-content video group were significantly higher. The interaction index and video duration and video information content quality showed a positive relationship. CONCLUSIONS Although the quality of the videos shared by patients on YouTube was generally moderate, the content of the information was generally poor. Nevertheless, it should be considered that YouTube videos can be a source of information for patients who want to have surgery, which can affect the process.

Abstract: OBJECTIVES To evaluate the effectiveness of distalizing maxillary first molars (U6) by temporary anchorage devices (TADs) according to their location (palatal, buccal, and zygomatic), their number, and appliance design. MATERIALS AND METHODS An electronic search of maxillary molar distalization with TADs was done through April 2023. After study selection, data extraction, and risk-of-bias assessment, meta-analyses were performed for the extent of distalization, distal tipping, and vertical movement of U6 using the generic inverse variance and random-effects model. The significance level was set at 0.05. RESULTS Forty studies met the inclusion criteria: 4 randomized controlled trials (RCTs), 13 prospective studies, and 23 retrospective studies (total of 1182 patients). Distalization of the U6 was not significantly greater (P = .64) by palatal (3.74 mm) and zygomatic (3.68 mm) than by buccal (3.23 mm) TADs. Distal tipping was significantly higher (P < .001) in nonrigid (9.84°) than in rigid (1.97°) appliances. Vertical movement was mostly intrusive and higher but not significantly different (P = .28) in zygomatic anchorage (-1.16 mm). CONCLUSIONS Distalization of U6 with TADs can be an effective and stable treatment procedure, especially when performed with rigid palatal appliances. However, further RCTs or prospective cohort studies are strongly recommended to provide more clinical evidence.

Abstract: OBJECTIVES To evaluate the predictability of the Invisalign appliance (Align Technology, Santa Clara, Calif) in leveling the maxillary curve of Spee (COS). MATERIALS AND METHODS A retrospective sample of adult subjects treated with the Invisalign appliance between 2013 and 2019 were selected. Patients were treated nonextraction in the maxillary arch and had either Angle Class I or II malocclusions with a minimum of 14 aligners with no bite ramps. Initial, predicted, and actual outcomes were analyzed with Geomagic Control X software (version 2017.0.3; 3D Systems, Cary, NC). RESULTS A sample of 53 cases satisfied inclusion/exclusion criteria. Paired t-tests demonstrated a significant difference between mean predicted and actual maxillary COS leveling with a shortfall of 0.11 mm (SD = 0.37; P = .033). Planned intrusion tended to be more accurate posteriorly with an overexpression of 117% for the first molars. Planned extrusion was the least accurate, with the mid-arch demonstrating expressions of -14% to -48%. These teeth intruded despite a prescribed extrusive movement. CONCLUSIONS The Invisalign appliance did not accurately predict maxillary COS leveling. Planned intrusive movements were overcorrected, and planned extrusive movements were either undercorrected or resulted in intrusion. This effect was most apparent for the upper first molar, which expressed 117% and -48% of planned intrusion and extrusion, respectively.

Abstract: OBJECTIVE To compare the efficacy and efficiency of treatment with clear aligners (CAT) vs fixed appliances (FAT) in adolescents with Class I and II moderate to severe malocclusions. MATERIALS AND METHODS One operator's (Garfinkle) cases from 2014 to 2019, started at age 12-18 years, with pre- and posttreatment records were identified and used according to an institutional review board-approved protocol. Records were measured by two calibrated, blinded investigators, aided by software (OrthoCAD [Cadent, Fairview, N.J.], Dolphin Imaging & Management Solutions [Chatsworth, Calif]). Discrepancy index (DI) and cast radiograph evaluation (CRE) scores, treatment duration, number of scheduled and emergency visits, and reported appliance and interarch elastic wear compliance were compared between groups using Wilcoxon rank sum and Fisher's exact tests. Cephalometric superimpositions were completed to evaluate craniofacial growth and dental changes. RESULTS Records from 72 cases met the criteria and were included. For the 47 CAT and 25 FAT cases, mean DI (21 ± 5 and 24 ± 8, respectively; P = .20) and CRE (35 ± 10 and 34 ± 9, respectively; P = .90) scores were not significantly different. Other case attributes and reported appliance and interarch elastic wear compliance were also not significantly different. CAT vs FAT cases had significantly smaller treatment durations (24 ± 6 vs 27 ± 5 months; P = .01) and visit numbers (16 ± 5 vs 24 ± 4; P < .01), but emergency visit numbers were not significantly different (2 ± 2 vs 3 ± 2; P = .08). CONCLUSIONS In adolescents with Class I and II malocclusions and moderate to severe DI scores, on average, CAT vs FAT cases were completed 3 months faster with eight fewer visits, but treatment efficacy was not significantly different.

Abstract: ABSTRACT Objectives To compare facial growth prediction models based on the partial least squares and artificial intelligence (AI). Materials and Methods Serial longitudinal lateral cephalograms from 410 patients who had not undergone orthodontic treatment but had taken serial cephalograms were collected from January 2002 to December 2022. On every image, 46 skeletal and 32 soft-tissue landmarks were identified manually. Growth prediction models were constructed using multivariate partial least squares regression (PLS) and a deep learning method based on the TabNet deep neural network incorporating 161 predictor, and 156 response, variables. The prediction accuracy between the two methods was compared. Results On average, AI showed less prediction error by 2.11 mm than PLS. Among the 78 landmarks, AI was more accurate in 63 landmarks, whereas PLS was more accurate in nine landmarks, including cranial base landmarks. The remaining six landmarks showed no statistical difference between the two methods. Overall, soft-tissue landmarks, landmarks in the mandible, and growth in the vertical direction showed greater prediction errors than hard-tissue landmarks, landmarks in the maxilla, and growth changes in the horizontal direction, respectively. Conclusions PLS and AI methods seemed to be valuable tools for predicting growth. PLS accurately predicted landmarks with low variability in the cranial base. In general, however, AI outperformed, particularly for those landmarks in the maxilla and mandible. Applying AI for growth prediction might be more advantageous when uncertainty is considerable.

Abstract: To establish consensus recommendations for clinicians to manage white spot lesions (WSLs) during orthodontic treatment.Three task force members reviewed the literature to identify best practices for minimizing WSLs during orthodontic treatment. Each draft statement was read to the task force members by a facilitator, followed by voting, accepting, or editing if necessary. The statements were then sent electronically by an independent third party (Magellan Medical Technology Consultants Inc, Minneapolis, Minn) to a previously formed content validation panel consisting of 20 independent private practitioners and clinical academicians for validation.Twenty-one statements were developed and sent for content validation. While 19 statements achieved a content validation index (CVI) of 0.78, two items did not. These items were edited by the task force members based on qualitative feedback from content validation participants. Each of these revised statements did achieve a CVI of 0.78 on second evaluation from the content validation panelists and therefore were included in this document.To reduce the risk of WSLs, it is essential to implement individualized caries management measures based on a comprehensive assessment of the patient's oral and systemic health. Effective at-home and professional mechanical and chemical plaque control should be implemented for high-risk orthodontic patients. Fluoride to support prevention and materials such as orthodontic sealants should also be used to provide a physical barrier around the brackets in high-risk patients. By following these guidelines, orthodontic professionals can help promote oral health and minimize the need for restorative treatment.

Abstract: ABSTRACT Objectives To investigate the accuracy of the Invisalign appliance in achieving predicted angular tooth movement of the maxillary central incisors, to locate the center of rotation in a labio-palatal direction, and to investigate any difference between 1-weekly and 2-weekly wear protocols. Materials and Methods This study involved a retrospective sample of two groups of 46 Class I adult subjects treated non-extraction with different protocols of 1-weekly and 2-weekly wear. The pretreatment, predicted outcome and achieved outcome digital models were superimposed and measured using metrology software. Angular and center-of-rotation measurements in the sagittal plane for the maxillary right central incisor were analyzed. Results There was a statistically significant difference between predicted and achieved angular measurements (P &lt; .005) for labial tooth movements regardless of wear protocol. For palatal movements, no statistically significant difference was observed (P &gt; .05). A small amount of overexpression was observed in some cases. Regarding crown and root control, uncontrolled tipping was the most predictable. No statistically significant difference was found between predicted and achieved center of rotation, but the confidence interval was wide. No statistically significant difference (P &gt; .05) was found between the two wear protocols for the parameters measured. Conclusions For maxillary central incisors, labial angular movements were not as accurate as palatal movements. Overcorrection could be recommended with careful clinical monitoring due to the possibility of overexpression. Control of root movements may be unpredictable, and further research is required to draw stronger conclusions. For the parameters measured in this clinical sample, there was no difference between the two wear protocols.

Abstract: OBJECTIVES The objectives of this article were the following: (1) to analyze bone thickness and height (BTH) of the buccal shelf area (BS) quantitatively in four different potentially eligible sites for miniscrew insertion; (2) to compare and contrast BTH and the changes in spatial position of the inferior alveolar nerve canal (IANC); and (3) to assess differences with age among vertical facial patterns (hypodivergent, normodivergent, and hyperdivergent) and well as by sex. MATERIALS AND METHODS Cone-beam computed tomography scans of 205 individuals (110 women and 95 men) were divided into groups according to age, vertical facial pattern, and sex. The BTH of the BS and the BTH to the IANC were measured in the mesial and distal roots of the first and second molars. RESULTS BTH progressively increased in a posterior direction (P < .001), while BTH to the IANC increased and decreased (P < .001) for thickness and height, respectively, in the same direction in all age groups, for the three different vertical facial patterns, and in both sexes. Women showed significantly less BTH to the IANC (P < .002). Hypodivergent patients had greater BTH (P < .024) and a smaller bone height to the IANC (P < .018) only in the first molar region. Patients over 40 years of age had lower bone height in the second molar area (P < .003). CONCLUSIONS The ideal place for BS miniscrew insertion is the region of the distal root of the second molars, regardless of facial pattern, sex, and age. The BS in women has less BTH and less BTH to the IANC.

Abstract: OBJECTIVES To compare four first premolar extraction and nonextraction treatment effects on intra-arch width, profile, treatment duration, occlusal outcomes, smile aesthetics and stability. MATERIALS AND METHODS An electronic search of the literature to June 2, 2023 was conducted using health science databases, with additional search of gray literature, unpublished material, and hand searching, for studies reporting nonsurgical patients with fixed appliances regarding sixteen sub-outcomes. Data extraction used customized forms, quality assessed with ROBINS-I (Risk Of Bias In Non-randomized Studies-of Interventions) and Cochrane RoB 2 (risk-of-bias) tool. GRADE (Grading of Recommendations Assessment, Development and Evaluation) assessed certainty of evidence. RESULTS Thirty (29 retrospective studies, 1 randomized controlled trial) studies were included. Random-effect meta-analysis (95% CI) demonstrated maxillary (MD: -2.03 mm; [-2.97, -1.09]; P < .0001) and mandibular inter-first molar width decrease (MD: -2.00 mm; [-2.71, -1.30]; P < .00001) with four first premolar extraction; mandibular intercanine width increase (MD: 0.68 mm; [0.36, 0.99]; P < .0001) and shorter treatment duration (MD: 0.36 years; [0.10, 0.62]; P = .007) in the nonextraction group. Narrative synthesis included three and five studies for upper and lower lip-E plane, respectively. For American Board of Orthodontics Objective Grading System and maxillary/mandibular anterior alignment (Little's irregularity index), each included two studies with inconclusive evidence. There were no eligible studies for UK Peer Assessment Rating (PAR) score. Class I subgroup/sensitivity analyses favored the same results. Prediction interval indicated no significant difference for all outcomes. CONCLUSIONS Four first premolar extraction results in maxillary and mandibular inter-first molar width decrease and retraction of upper/lower lips. Nonextraction treatment results in mandibular intercanine width increase and shorter treatment duration. There was no significant difference between the two groups regarding maxillary intercanine width, US PAR score, and posttreatment smile esthetics. Further high-quality focused research is recommended.

Abstract: ABSTRACT Objective To evaluate the responsiveness of three cone-beam computed tomography (CBCT) transverse analyses (University of the Pennsylvania [UPenn] analysis, Boston University analysis and Yonsei University [YU] analysis). Materials and Methods A consecutive cohort sample of patients was retrospectively reviewed for eligibility. CBCT records before treatment (T0) and immediately after maxillary expansion (T1) of 71 patients receiving tooth-supported rapid maxillary expansion (RME) and 57 patients receiving mini-screw-assisted RME (MARME) were finally analyzed. Responsiveness was assessed by comparing changes of measures (T1-T0) to mid-palatal suture opening distance (MSOD) at T1. Correlational responsiveness was assessed by Pearson correlation coefficient (r). Absolute agreement responsiveness was assessed by Bland-Altman analysis. A specialized intraclass correlation coefficient (ICC) was selected to assess responsiveness combining correlation and absolute agreement. Results Changes of all three measures were moderately to strongly correlated to MSOD (r &gt; 0.5). The highest correlation coefficient (0.79) was found between the YU analysis and MSOD. When exploring absolute agreement responsiveness, the smallest deviation (0.14 mm) was observed in the UPenn analysis. For ICC, the highest ICC value (0.63) was observed when the YU analysis was used. In addition, all three measurements were more responsive to MSOD in the MARME group than to those in RME group. Conclusions All three transverse measurements responded well to true changes of maxillary transverse deficiency during both tooth-supported and mini-screw-assisted RME. Deviations of responsive properties of these measurements from true skeletal changes were below a clinically meaningful level (1 mm).

Abstract: OBJECTIVES To evaluate the efficacy of chewing gum on the intensity of pain in patients undergoing orthodontic treatment. MATERIALS AND METHODS A search strategy that included both a manual search and a search of electronic databases was implemented; the electronic databases included PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), ScienceDirect, Scopus, and EBSCO. Only randomized controlled trials were included in this study. All of the studies were assessed independently and in duplicate in accordance with the exclusion and inclusion criteria. The Cochrane risk of bias tool was used to evaluate the risk of bias within the included studies, and the GRADE approach was used to evaluate the certainty of evidence. RESULTS Sixteen RCTs were included in the final analysis. The meta-analysis revealed that chewing gum significantly reduced pain intensity in comparison to pharmacologic agents (mean difference [MD] -0.50 [95% confidence interval {CI} -0.90 to -0.10], P = .01). When compared with a placebo, chewing gum significantly reduced pain intensity (MD -0.60 [95% CI -1.06 to -0.13], P = .01), while bite wafer and chewing gum groups had the same levels of reduction in pain intensity (MD -0.15 [95% CI -0.56 to -0.26], P = .48). CONCLUSIONS In patients undergoing fixed orthodontic treatment, chewing gum was significantly more effective than both pharmacologic agents and placebo in reducing orthodontic pain 24 hours after the initial placement of the archwire.

Abstract: OBJECTIVES To investigate skeletal and dentoskeletal changes 20 years after bionator treatment. MATERIALS AND METHODS Analog lateral cephalograms of 18 subjects treated with a bionator appliance during growth were digitized with a transmitted light scanner. Inclusion criteria were: increased overjet (≥4 mm), skeletal Class II, available lateral cephalograms before (T0), after (T1), and 20 years after (T2) treatment with only a Bionator. To assess standard cephalometric parameters, the software ivoris analyze was used. Data were analyzed using Friedman's two-way analysis of variance by ranks followed by Dunn's post hoc tests (P ≤ .05). RESULTS During therapy (T0-T1), ANB decreased significantly by 1.9° and remained unchanged long term. SNA slightly decreased (-0.6°) during treatment, SNB and SNPg increased (+1.4°, +1.7°). All three parameters showed a significant increase at T2 (+1.2°, +1.6°, +1.6°). Vertical measurements (ML-NL, ML-NSL, NL-NSL) remained almost unchanged during therapy. NL-NSL also was unchanged during the long-term interval; ML-NSL and ML-NL decreased significantly (-3.4°, -4.9°). During treatment, the maxillary incisors retroclined (OK1-NL: -1.6°, OK1-NA: -0.6°), the mandibular incisors proclined (UK1-ML: +3.5°, UK1-NB: +4.9°), neither significantly. Long term, there was a nonsignificant tendency toward proclination of upper (OK1-NL: +0.1°, OK1-NA: +0.7°) and retroclination of lower incisors (UK1-ML: -1.5°, UK1-NB: -5°). CONCLUSIONS Changes of ANB after bionator treatment without additional fixed appliances remained stable after 20 years. The observed long-term changes are probably consequences of well-known physiological and age-related processes.

Abstract: OBJECTIVES To evaluate the force required to promote the failure of fixed orthodontic retainers with different adhesive (composite) coverage and to assess the presence and extent of force propagation with two different orthodontic retainer wires. MATERIALS AND METHODS Ortho-FlexTech and Ortho-Care Perform (0.0175 inches), each of 15-cm length, were bonded on acrylic blocks with different adhesive surface diameters (2 mm, 3 mm, 4 mm, and 5 mm). The samples (n = 160) were subjected to a tensile pull-out test, and debonding force was recorded. Fixed retainers using two different wires and 4-mm adhesive diameter were bonded on acrylic bases resembling a maxillary dental arch (n = 72). The retainers were loaded occluso-apically until the first sign of failure while being video recorded. Individual frames of the recordings were extracted and compared. A force propagation scoring index was developed to quantify the extent of force transmission under load. RESULTS A 4-mm adhesive surface diameter required the highest debonding force for both retainer wires with significant differences compared with 2 mm (P < .001; 95% confidence interval [CI]: 8.69, 21.69) and 3 mm (P = .026; 95% CI: 0.60, 13.59). Force propagation scores were significantly higher for Ortho-Care Perform. CONCLUSIONS Based on this laboratory-based assessment, consideration should be given to the fabrication of maxillary fixed retainers using a minimum of 4-mm diameter composite coverage on each tooth. Force appeared to propagate more readily with Ortho-Care Perform than with a flexible chain alternative. This may risk stress accumulation at the terminal ends with potential for causing associated unwanted tooth movement in the presence of intact fixed retainers.

Abstract: OBJECTIVES The objective of this study was to assess bone biomarkers and cytokines in patients with conventional labial appliances (CLAs) and aligners. MATERIALS AND METHODS Participants were recruited to undergo orthodontic treatment with CLAs and aligners according to predefined inclusion and exclusion criteria. Periodontal examination was accomplished at baseline and 4 weeks using the plaque index (PI), gingival index (GI), and bleeding on probing (BoP). Samples of gingival crevicular fluid (GCF) were collected at baseline (T0) before the start of treatment and at the 1-month follow-up (T1) to assess bone metabolic and inflammatory biomarkers. GCF from participants with CLAs and aligners was evaluated with enzyme-linked immunosorbent assay. Comparison between labial conventional orthodontic treatment and aligners were assessed using an unpaired t-test. The difference between T0 and T1 was measured using a paired t-test. RESULTS BoP, PI, and GI demonstrated no significant difference between participants treated with aligners and subjects with CLAs at baseline and at 4 weeks (P > .05). Bone markers and other biomarkers (tumor necrosis factor α, interleukin [IL]-α, IL-2, IL-6, and IL-8) showed significant differences (P < .05). Also, a significant difference between CLAs and aligners was noted among all biomarkers (P < .05) except IL-β. CONCLUSIONS Aligners and CLAs increase the level of inflammatory and bone metabolic biomarkers after 1 month.

Abstract: OBJECTIVES To investigate the volumetric changes of the lower incisor roots in skeletal Class III orthodontic patients with anterior crossbite after premolar extraction therapy. MATERIALS AND METHODS Thirty-six adults, aged 18-28 years, had four-premolar extraction treatment. Pre- and posttreatment cone-beam computed tomography (CBCT) images were used to assess the thickness and height of alveolar bone, root volume, and length. A paired t-test was used to detect changes in root volume and length before and after treatment. Pearson's correlation analysis was applied to estimate the correlation between root volume and dentoskeletal morphology. RESULTS Both the central and lateral incisors had intrusion and tipping movement after treatment. Compared with pretreatment data, root length decreased significantly. The lingual root volume of root cervical, apical third, and the labial root volume of the root apical third decreased significantly (P < .05), among which the percentage of tooth loss at the tip volume was the highest. The pretreatment height of the alveolar ridge crest, thickness of the alveolar bone, and type of incisor movement were related to the volume and length loss. CONCLUSIONS Volume and length loss in the apical third of the lower incisor roots in skeletal Class III patients treated with a Class III bicuspid extraction pattern is common. The pretreatment height of the alveolar ridge crest, thickness of the alveolar bone, and type of tooth movement are related to the loss.

Abstract: Clear aligners have become increasingly popular in orthodontics as an attractive and removable alternative to traditional fixed-appliance treatment. However, the effective implementation of torque and the maintenance of adequate anchorage pose challenges for clear aligner therapy. Torque in orthodontics,1–4 which involves rotational force necessary for root movement, and anchorage,5 which refers to stability and prevention of unwanted tooth movement, are critical parameters in orthodontic treatment and require careful consideration of biomechanics.Traditionally, torque is achieved by applying a couple, which consists of opposite forces with equal magnitudes in different, parallel lines of action.3 Fixed appliances can generate high-force loads concentrated around bracket slots, enabling effective torque development in all dimensions. In contrast, clear aligners have struggled to generate comparable couples required for torque implementation during treatment. In addition, anchorage is better controlled with fixed appliances due to their relatively rigid nature and strong adhesion to neighboring teeth, allowing this trait to manifest itself. Clear aligners face challenges in providing optimal anchorage due to the material from which they are made, their removable nature, and the absence of fixed attachments, leading to potential anchorage loss and unwanted tooth movement. Over the years, using different conventional and, later, optimized attachments partially to resolve these problems did not solve the anchorage or the couple construction problems.6In orthodontics, force application is categorized based on the number of force points involved: one-, two-, and three-point force applications, each yielding distinct tooth movement outcomes.7,8One-point force application involves applying a force vector away from the tooth's center of resistance (Cres), resulting in uncontrolled tipping. This movement causes the apex and incisal edge to move in opposite directions while the tipping center of rotation (Crot) is near, but apical to, the Cres. In extremely rare cases, when the force vector passes through the Cres, it can result in bodily movement, including true intrusion and extrusion, two movements that aligners cannot accomplish. Tipping by itself can produce only relative, but not true, intrusion and extrusion.Two-point force application, known as a "couple," involves the intentional application of opposite forces equal in magnitude to generate torque. This primary torque refers to rotational movement around the couple's center, depending on how the appliance is restrained, primarily affecting the apex (root movement). It is important to note that torque is typically related to a short-term movement performed during the finishing phase of orthodontic treatment in the anterior region. However, torque is used in almost all stages of fixed appliance orthodontics, from leveling and alignment, opening and closing spaces, intrusion and extrusion, up to the finishing stage, where minute, exact movements are needed. Most of the time, the couple expresses itself without any specific involvement of the orthodontist. It is "all included" in the edgewise system itself.Three-point force application combines tipping and couple movements, such as the closure process of an extraction space in fixed-appliance treatment. This movement pattern, known in the profession as "walking," is usually achieved by applying a one-point force application that initially tips the crown backward and the root forward until a two-point force application, a couple within the bracket slot, develops. This secondary, developmental couple helps upright the tooth by moving the apex to the point at which new tipping is built. However, this movement pattern has not been replicated with removable appliances, including clear aligners. Therefore, despite the advantages offered by clear aligners, such as improved esthetics, hygiene, and patient comfort, their biomechanical limitations in torque implementation and anchorage control need to be addressed.Existing attempts to improve material properties, aligner design, and auxiliary appliances or attachments have not yielded significant improvements.9,10Orthodontic torque requires continuous and long-lasting, high-level force application in the same location and relies on higher loads from neighboring teeth for anchorage.3 Removable appliances inherently lack the stability and firmness required to maintain a couple over an extended period.11 In addition, the absence of fixed attachments between the aligners and the teeth prevents the development of adequate anchorage. Despite advancements in material stiffness and the use of attachments, the removable nature of aligners hinders their ability to consistently generate the desired torque, even with the best artificial intelligence systems whenever used.Accurate determination and measurement of torque changes require a comparison of short-term, consecutive lateral cephalograms or dedicated cone-beam computed tomography scans before and immediately after the designated torque movement with reference points dedicated to measuring this movement change.3,4 Measuring tooth inclination changes during full or long-term treatment periods does not measure orthodontic torque-dedicated movements. Measuring buccal segment torque changes is beyond the scope of this article.Although the Raintree EssixR appliance (the forefather of clear aligners) claimed to engage torque as a possible trait, no supporting randomized controlled trial exists. While graphical representations in textbooks and the media may be convincing, a force system analysis reveals that the ditches in the removable plastic aligners contradict the effective delivery of torque.12In conclusion, it is widely acknowledged within the profession that clear aligners have difficulty delivering orthodontic torque, and this limitation is likely to persist as long as the appliance remains removable. Rigorous scientific research, including well-designed, randomized controlled studies, is crucial to validate biomechanical outcomes and the ability to maintain anchorage in order to establish clear aligners as a reliable alternative to fixed appliances.

Abstract: OBJECTIVES To evaluate the effect of systemic administration of omega-3 fatty acids on orthodontic tooth movement (OTM) with histological analysis. MATERIALS AND METHODS OTM was induced in 20 adult albino New Zealand rabbits, divided into omega-3 and control groups, with nickel-titanium coil springs for 21 days. Omega-3 or saline was given every day via oral gavage during the experimental period. Animals were sacrificed for histomorphometric analysis of alveolar bone remodeling after 21 days of OTM. RESULTS A significant difference in OTM amount was found in the third week of OTM with means of 1.445 ± 0.13 and 1.72 ± 0.15 for the experimental and control groups, respectively. Histomorphometric analysis showed a significant reduction in the area of active bone-resorptive lacunae and a significant increase in osteoblastic activity in the omega-3 group after 3 weeks. CONCLUSIONS Strong evidence of the osteoclastic inhibitory effect of systemic omega-3 was found, which reduced the percentage and amount of OTM.

Abstract: To evaluate the bisphenol release of different brands of clear aligner materials.Six different clear aligner materials were used in this study: Duran (Scheu-Dental GmbH, Iserlohn, Germany), Zendura Flx (Bay Materials LLC, Fremont, CA, USA), Zendura A (Bay Materials), Essix (Raintree Essix Inc., Metairie, LA, USA), Taglus Premium (Laxmi Dental Export Pvt. Ltd, Mumbai, India), and Smart Track (Align Technology, San Jose, CA, USA). The samples were kept in saline solution for 8 weeks in airtight test tubes at 37°C. The ratio between the weights of the samples and the volumes of the dilutions was prepared as 0.1 g/mL as suggested by International Standards Organization parameters. To evaluate the bisphenol release of materials, liquid chromatography-mass spectrometry/mass spectrometry analysis was performed. Data were analyzed with the Kruskal-Wallis test (α = 0.05).Bisphenol A (BPA) values in Smart Track were found to be significantly higher than the Zendura A and Zendura Flx groups (P = .02, P = .03, respectively). There was no statistically significant difference among the samples in terms of Bisphenol F (BPF) values (P = .108). In terms of Bisphenol S (BPS) values, a statistically significant difference was found (P = .002) indicating that Smart Track released significantly more BPS than Zendura A (P = .001).Under the test conditions, the amounts of leached BPA, BPF, and BPS were less than the reference dose for daily intake. However, the cumulative effect of these appliances should not be underestimated.

Abstract: OBJECTIVES To evaluate the effects of treatment of posterior crossbite (PXB) in the mixed dentition with the Function Generating Bite (FGB) appliance on the transverse dimension of the dental arches. MATERIALS AND METHODS This study included 84 PXB patients (female = 46; male = 38; mean age, 8.2 ± 1.8 years) and 69 control (C) patients (female = 31; male = 38; mean age, 8.9 ± 1.4 years). Measurements were taken with digital calipers on maxillary and mandibular study casts before (T0) and after (T1) treatment for the following measures: intermolar (IMD), intermolar gingival (IMGD), intercanine (ICD), and intercanine gingival distances (ICGD). RESULTS At T0, there was a significant difference in all maxillary measurements between the PXB and C groups (P < .001), reflecting maxillary hypoplasia in PXB patients. At T1, there was no difference between the groups. In PXB patients, the mean increase between T0 and T1 for IMD was 4.34 ± 2.42 mm; this difference measured 3.51 ± 2.19 mm for IMGD, 2.78 ± 2.37 mm for ICS, and 1.89 ± 1.7 mm for ICGD. There was no significant difference in mandibular measurements between groups at T0 and T1. CONCLUSIONS Functional therapy with FGB is effective in significantly increasing the transverse dimension of the maxillary dental arch in PXB patients. Considering its efficacy in treating masticatory dysfunction, FGB may be considered a good treatment option for the correction of PXB in growing children.

Abstract: OBJECTIVES To assess the effect of piezocision on periodontal tissues and alveolar bone height and to detect lower second molar root resorption in piezocision-assisted mandibular second molar protraction compared to no-piezocision molar protraction. MATERIALS AND METHODS Twenty-one subjects (four males, 17 females, aged 22.43 ± 2.83 years) who presented with bilateral extraction of lower first molars were included. The patients were divided into two groups; Group 1: Piezocision-assisted molar protraction (right or left side of subjects) in which piezocision was performed immediately before lower second molar protraction and, Group 2: No-piezocision molar protraction in which lower second molar protraction was not surgically assisted. Plaque index (PI), gingival index (GI), periodontal pocket depth (PPD), width of keratinized gingiva (WKG), gingival recession (GR), lower second molar mesial root resorption, alveolar bone height, and mandibular bone height were recorded at T1 (immediately before molar protraction) and at T2 (after second molar space closure). RESULTS In the piezocision-assisted molar protraction group, significant changes were detected in the WKG (P < .001), GR (P < .05), and the mandibular bone height (P < .001). Compared to the no-piezocision group, piezocision-assisted molar protraction resulted in an increased WKG (P < .001) and less second molar mesial root resorption (P < .01). CONCLUSIONS Piezocision does not have any detrimental effect on the periodontium and produces less root resorption.

Abstract: OBJECTIVES To investigate the association between the width of keratinized gingiva (WKG), gingival phenotype (GP), and gingival thickness (GT) with craniofacial morphology in sagittal and vertical dimensions. MATERIALS AND METHODS WKG, GP, and GT of mandibular anterior teeth in 177 preorthodontic patients (mean age 18.38 ± 5.16 years) were assessed clinically using a periodontal probe, a Colorvue Biotype Probe, and ultrasound by a single examiner. Patients were grouped into skeletal Class I, II, and III and hyperdivergent, normodivergent, and hypodivergent based on ANB and SN-MP angles. Mandibular incisor inclination (L1-NB) was also measured. Clinical and cephalometric measurements were repeated to assess inter- and intraexaminer reproducibility. RESULTS A significant association was found between thin GP and skeletal Classes I and III for the left mandibular central incisor (MCI; P = .0183). In skeletal Class III patients, L1-NB angle demonstrated a decreasing trend as phenotype thickness decreased. A significant association was found between thin phenotype and normodivergent and hypodivergent groups for MCIs (left: P = .0009, right: P = .00253). No significant association between WKG or GT and craniofacial morphology was found. CONCLUSIONS Thin GP is associated with skeletal Class I and III for the left MCI. Thin GP is associated with hypodivergent and normodivergent skeletal patterns for the MCIs. There was no association between WKG and GT and craniofacial morphology in both skeletal and vertical dimensions. Dental compensations that exist due to different craniofacial morphology may influence the GP.