Retraction Of Anterior Teeth Research Articles

Three-dimensional assessment of periodontal support of lower incisors for skeletal Class II malocclusion undergoing presurgical orthodontic treatment with different vertical skeletal patterns

BackgroundThe aim of the present study was to compare periodontal support changes during retraction of mandibular anterior teeth for skeletal Class II malocclusion with different facial divergence and to analyze relevant factors influencing bone remodeling by applying three-dimensional (3D) cone-beam computed tomography (CBCT) reconstruction technology.MethodsForty-eight patients with Class II malocclusion requiring surgical orthodontic treatment enrolled in the study were divided into the hyperdivergent group (n = 16), normodivergent group (n = 16) and hypodivergent group (n = 16) according to their vertical skeletal patterns. Cone-beam computed tomography (CBCT) scans were obtained before treatment (T1) and after presurgical orthodontic treatment (T2). The two-dimensional (2D) alveolar bone morphology, movement of mandibular central incisors and volume of the alveolar bone around incisors were measured on the labial and lingual sides by 3D CBCT reconstruction technology. Statistical analyses were performed with one-way ANOVA, paired t tests and multiple linear regression.ResultsDuring presurgical orthodontic treatment, the alveolar bone height on the labial side of the hyperdivergent group decreased significantly (P ≤ 0.05), but was maintained in the normodivergent and hypodivergent groups (P > 0.05). However, the alveolar bone volume, alveolar bone thickness at each level and alveolar bone height on the lingual side decreased significantly for all the groups. Apart from the initial morphometric measurements at T1, the morphology of lingual alveolar bone at T2 was significantly influenced by the direction and amount of tooth movement. Horizontal retraction and vertical protrusion of the root apex were negatively related to the alveolar bone on the lingual side after presurgical orthodontic treatment.ConclusionFor Class II malocclusion patients undergoing presurgical orthodontic treatment, the changes in the periodontal support of the lower central incisors varied in different vertical skeletal patterns. There exists a great periodontal risk of alveolar bone resorption on the lingual side for various vertical types. To avoid alveolar bone deterioration, it is essential to investigate the bone remodeling of patients with different alveolar bone conditions and cautiously plan tooth movement prior to orthodontic treatment. Moreover, 3D measurements based on CBCT construction can provide complementary information to traditional 2D measurements.

Patient-Reported Outcome Measures of Flapless Corticotomy with Low-Level Laser Therapy in En Masse Retraction of Upper Anterior Teeth: A Three-Arm Randomized Controlled Trial.

(1) Background: This study aimed to compare patient-reported outcome measures when accelerating en masse retraction between the piezocision procedure and the subsequent application of low-level laser therapy (FC+LLLT), with the piezocision alone (FC), and in a control group. (2) Methods: A three-arm randomized controlled trial (RCT) was conducted involving 60 patients (41 females and 19 males) with Class II division I malocclusion. The en masse retraction was performed using NiTi closed coil springs attached to miniscrews. The LLLT was performed using an 808 nm Ga-Al-As diode laser. Patient responses regarding pain, discomfort, swelling, and chewing difficulties were reported at ten assessment points. (3) Results: The greatest pain levels were observed 24 h after the application of force during the first and third months of retraction. The mean pain, discomfort, swelling, and chewing difficulties were significantly smaller in the control group than in the FC and FC+LLLT groups. High satisfaction levels were reported in all three groups (p < 0.05). (4) Conclusions: The accelerated en masse retraction via piezocision, followed by a small course of LLLT, was accompanied by significantly fewer pain, discomfort, and chewing difficulties than the control group. LLLT is a valuable addition to piezocision, with an improved patient experience.

The displacement of teeth and stress distribution on periodontal ligament under different upper incisors proclination with clear aligner in cases of extraction: a finite element study

ObjectivesTo investigate the displacement of dentition and stress distribution on periodontal ligament (PDL) during retraction and intrusion of anterior teeth under different proclination of incisors using clear aligner (CA) in cases involving extraction of the first premolars.MethodsModels were constructed, consisting of the maxilla, PDLs, CA and maxillary dentition without first premolars. These models were then imported to finite element analysis (FEA) software. The incisor proclination determined the division of the models into three groups: Small torque (ST) with U1-SN = 100°, Middle torque (MT) with U1-SN = 110°, and High torque (HT) with U1-SN = 120°. Following space closure, a 200 g intrusion force was applied at angles of 60°, 70°, 80°, and 90° to the occlusal plane, respectively.ResultsCA therapy caused lingual tipping and extrusion of incisors, mesial tipping and intrusion of canines, and mesial tipping of posterior teeth in each group. As the proclination of incisors increased, the incisors presented more extrusion and minor retraction, and the teeth from the canine to the second molar displayed an increased tendency of intrusion. The peak Von Mises equivalent stress (VMES) value successively decreased from the central incisor to the canine and from the second premolar to the second molar, and the VMES of the second molar was the lowest among the three groups. When the angle between the intrusion force and occlusal plane got larger, the incisors exhibited greater intrusion but minor retraction.ConclusionsThe "roller coaster effect" usually occurred in cases involving premolar extraction with CA, especially in patients with protruded incisors. The force closer to the vertical direction were more effective in achieving incisor intrusion. The stress on PDLs mainly concentrated on the cervix and apex of incisors during the retraction process, indicating a possibility of root resorption.

Long-term bone remodeling of maxillary anterior teeth with post-treatment alveolar bone defect in adult patients with maxillary protrusion: a prospective follow-up study

BackgroundAlveolar bone defects, particularly palatal bone dehiscence (PBD) and labial bone fenestration (LBF), occur frequently as a result of retraction of the maxillary anterior teeth. The study aims to explore the long-term bone remodeling of maxillary anterior teeth in adult patients with post-orthodontic treatment PBD and LBF.Materials and methodsThe study includes 24 adult patients with maxillary protrusion (8 males, 16 females) who were treated with extraction of four first premolars and had alveolar bone defects (PBD or LBF) in maxillary anterior teeth following orthodontic treatment. Cone-beam computed tomography imaging measurements were obtained before (T1), after (T2) orthodontic treatment, and after at least 1-year removable thermoplastic retainer retention (T3). The maxillary anterior teeth with PBD or LBF at T2 were divided into the PBD or LBF groups, respectively. The labial and palatal alveolar bone height (ABH), alveolar bone thickness (ABT), and movement of maxillary anterior teeth were measured during retraction (T2–T1) and retention (T3–T2) periods.ResultsThe incidence of PBD and LBF in maxillary anterior teeth significantly increased after orthodontic treatment and decreased during the retention period. In the PBD group, the palatal ABH of all maxillary anterior teeth significantly increased from T1 to T2 but decreased from T2 to T3. The ABT of the maxillary central incisor and canine significantly increased on the palatal side and decreased on the labial side during the retention period. In the LBF group, the labial ABT of the maxillary central incisor at the apical level showed a significant decrease from T1 to T2, followed by an increase from T2 to T3. In both groups, the maxillary central incisor showed significant labial movement, with a relative intrusion during the retention period.ConclusionFor adult patients with maxillary protrusion, the alveolar bone defect of maxillary anterior teeth caused by orthodontic retraction significantly improved during the retention period, indicating good long-term bone remodeling. Our findings suggest that a combination of spontaneous reorientation of maxillary anterior teeth and bone remodeling contributed to alveolar bone covering in these patients.

Three-dimensional finite element analysis of retracting pathological migration of the right upper central incisor with a clear aligner

We aimed to explore the best orthodontic step distance of the right upper central incisor with mild, moderate, and severe pathological displacement achieved via a clear aligner. Three-dimensional models of maxilla-tooth-periodontal ligament clear aligner of the right upper central incisors with five different steps of 0.1, 0.125, 0.15, 0.165, 0.25 mm and three different alveolar bone heights were established via finite element analysis. We analysed the changing trends in initial displacement, the periodontal ligament, the alveolar bone, and apical stress of right upper central incisor. In the process of retraction, the right upper central incisor a movement trend of the crown deviating from the distal root to the mesial, and with the decrease of the height of the alveolar bone and the increase of the displacement, the crown would appear distal labial torsion with a deepening trend of vertical overlay.The maximum stress distribution of the periodontal ligament and alveolar bone showed a positive correlation. The overall stress distribution of the periodontal ligament and apical stress increased with decrease of alveolar bone height and the increase of alveolar bone displacement. In patients with mild, moderate, and severe pathological displacement of the right upper central incisor, the best step distance of anterior tooth retraction is 0.165, 0.15, and 0.125 mm, respectively.

How Effective Are Non-Frictional Techniques Compared to Sliding Techniques in the Retraction of Upper Anterior Teeth When Using Buccal Fixed-Appliance Therapy? A Systematic Review

Methods for retracting the anterior teeth are divided into frictional methods and non-frictional methods. However, evidence regarding the superiority of one technique over the other is still lacking in the available literature. Therefore, we aimed to evaluate the current evidence regarding the effectiveness of frictional methods of anterior teeth retraction compared to the non-frictional ones. The extracted data included the mechanism of application of the retraction force and its intensity, the observation period, follow-up records, and outcome measures. Ten studies were included in this review; the results did not favor a specific technique regarding the rate of orthodontic tooth movement and loss of anchorage during canine retraction, although a preference was shown for the sliding technique in the rate of en-masse retraction (0.74 versus 0.39 mm/month) and the anchorage control during the retraction of the incisors (0.5 versus 0.1 mm/month). The control of the incisor’s torque during the en-masse retraction was higher when frictionless techniques were used (−12° versus −7°). Regarding the rate of orthodontic tooth movement, the non-frictional technique is characterized by a high sensitivity to the quality of the design, and the sliding technique was generally effective. As for controlling the torque of the incisors, the preference is for the non-frictional technique. Overall, there is a need to conduct more studies with an appropriate design.

A Comparative evaluation of stress distribution in bone and mini-implant during en-masse retraction of anterior teeth in maxilla using forces from anchorage units (mini-implants and molar hook) to both canine hook and arch wire hook. An FEM study

The study aimed to compare and evaluate the stress that was distributed around mini-implant, molar hook and anterior dentition during its en-masse retraction from both canine hook and arch-wire hook. Four FEM models of maxilla were created to carry out en-masse retraction of the anterior teeth using forces from mini-implant and molar hook to both arch-wire hook and canine hook. The force of 200 grams was applied with Ni-Ti closed coil spring in all four models to carry out anterior teeth retraction. Stress distribution were then analyzed. The mini-implant group showed higher stresses on the implant when compared to the molar hook group. The molar hook groups showed more stress on the dentition than that of the mini-implant group. The models where the arch-wire hook used for retraction showed less stress values on the bone, teeth, dentition, PDL when compared with that of the canine hook.The arch-wire hook can be considered a better option than the canine hook. When forces were applied to the arch-wire hook lesser stresses were seen on bone, teeth, dentition, and PDL. The implant-supported group showed lesser stress values on teeth when compared with that of the molar hook group.

Success rate of infrazygomatic crest mini-implants used for en-masse retraction of maxillary anterior teeth in first premolar extraction cases: A three-dimensional comparative prospective clinical trial between adolescents and young adults.

The purpose of this study was to compare the success rate of infrazygomatic mini-implants between adolescents and young adults. A total of 60 subjects of different age groups ie, (group I [adolescents]: 12-18 years, mean age: 14.9 ± 2.9 years; group II [young adults]: 19-25 years, mean age=21.9 ± 3.1 years) were assessed in the study. En-masse retraction of maxillary anterior teeth was carried out with extraction of upper first premolars with infrazygomatic crest (IZC) mini-implants as anchorage units. Clinical parameters such as success rate, soft tissue thickness, maximum insertion torque, maximum removal torque, pain response, soft tissue response, and cone-beam computed tomography parameters such as embedded angulation, penetration depth, thickness of bone on buccal and palatal aspect of mini-implant, and peri-implant bone density were evaluated. The success rate of IZC mini-implants in adolescents was found to be 96.6% and 98.3% in young adults respectively. There was no significant difference in success rate between the two groups. Intergroup comparison showed a significant difference (P < 0.05) in terms of maximum insertion torque, maximum removal torque, soft tissue thickness, cortical bone thickness, and peri-implant bone density values. Comparison between right and left side revealed a significant difference (P < 0.05) with regards to soft tissue response, soft tissue thickness, total bone thickness, cortical bone thickness, and peri-implant bone density. There was no significant difference in the success rate of IZC mini-implants between adolescents and young adults. Thus, the use of IZC mini-implants can be recommended in adolescents for successful orthodontic treatment.

A retrospective study of alveolar bone remodelling after anterior retraction in orthodontic tooth extraction cases with clear aligners and fixed appliances.

To evaluate alveolar bone dimensions and its relationship with tooth movement (retraction, intrusion and torque) during orthodontic treatment with fixed appliance and clear aligners. Thirty-two patients were included in this retrospective clinical study. Cone beam computed tomography (CBCT) was collected before and after treatment to measure the volume of dehiscence and fenestrations in the maxillary anterior region, anterior alveolar bone thickness and height and degree of tooth movement. Rank-sum tests were used to compare the differences in alveolar bone defect volumes between clear aligners and fixed appliance, multiple linear regression analysis was used for study evaluation, and kappa statistics were used to assess internal consistency and test-retest reliability. Post-operatively, most alveolar bone defects occurred on the labial side. The incidence of bone fenestration was 23.96% in the clear aligner group and 26.18% in the fixed appliance group, which was higher than the incidence of bone dehiscence (5.21%). The labial bone height decreased by 0.272 mm, and the palatal bone height increased by 0.617 mm for every 1 mm downward intrusion of the anterior tooth apex in the fixed appliance group. In the clear aligner group, there was no significant change in the labial bone height, and the palatal bone height decreased by 0.447 mm for every 1 mm of anterior tooth retraction coronally. In the fixed appliance group, anterior tooth intrusion and retraction may have led to alveolar bone resorption by its compression at the cervical level. This study provides a three-dimensional tooth movement evaluation method by using CBCT.

Evaluation of Patient-Centered Outcomes Associated With the Acceleration of en-Masse Retraction of Upper Anterior Teeth Assisted by Flapless Corticotomy Compared to Traditional Corticotomy: A Two-Arm Randomized Controlled Trial.

This study aimed to assess the levels of pain, discomfort, and functional impairment associated with the en-masse retraction of the upper anterior teeth when treating Class II division 1 malocclusion patients using traditional corticotomy or flapless corticotomy. In addition, an assessment of patients' satisfaction with the selected surgical intervention wasundertaken at one-month post-operatively. The study sample comprised 40 patients with Class II division 1 malocclusion, randomly assigned to either the traditional corticotomy group (n=20) or the flapless corticotomy group (n=20). Patients underwent extraction of the maxillary first premolars, and orthodontic mini-screws were placed between the maxillary second premolars and the first molars for skeletal anchorage. An en-masse retraction was accomplished in both groups. Patients were asked to fill in a questionnaire at 24 hours (T1), four days (T2), seven days (T3), 14 days (T4), and 28 days (T5) after the surgical intervention using standardized questionnaires. Most questions were answered on a visual analog scale where zero scores meant the absence of pain, discomfort, or functional impairment, and 100 scores meant the worst feelings of these traits. All patients in both groups entered data analysis with no dropouts. All measured levels were significantly greater in the traditional corticotomy group during the first two weeks following the corticotomy intervention in terms of pain perception (P˂0.001), discomfort (P=0.004), and difficulty in chewing (P=0.015). Additionally, during the first week following corticotomy, levels of perception of discomfort (P˂0.001), difficulty in swallowing (P=0.001), and limitation of jaw movement (P˂0.001) were significantly greater in the traditional corticotomy group. Patient satisfaction, the recommendation to a friend, and acceptance of flapless corticotomy were significantly greater than traditional corticotomy (P=0.002, P=0.001, respectively). 78% of patients in the traditional corticotomy group considered it more discomfort than a tooth extraction, while 50% of patients in the flapless corticotomy group considered tooth extraction more discomfort, with a significant difference between the two groups (P=0.001). The levels of negative patients' reported outcomes were significantly smaller with flapless corticotomy than with traditional corticotomy. Traditional corticotomy was associated with mild to moderate levels of pain, swallowing difficulty, moderate levels of discomfort, chewing difficulty, and jaw movement limitation after 24 hours of the surgical procedure. In contrast, flapless corticotomy was less problematic and associated with mild pain, swelling, chewing difficulty, jaw movement limitation, and swallowing difficulty at the same assessment time. Patient satisfaction, acceptance, and recommendation to a friend were greater for flapless corticotomy than traditional intervention.

Three-dimensional morphologic analysis of the maxillary alveolar bone after anterior tooth retraction with temporary anchorage devices.

To investigate three-dimensional (3D) morphologic changes in the alveolar bone around the maxillary central incisors of patients who underwent premolar extraction and subsequent anterior tooth retraction using temporary anchorage devices (TADs). The subjects consisted of 16 patients with bimaxillary protrusion. The maxillary anterior teeth were retracted using sliding or loop mechanics and TADs for anchorage reinforcement. Cephalograms and computed tomography scans taken pretreatment and posttreatment were registered with respect to the palatal structures. The movement of the maxillary central incisors and morphologic changes in the anterior alveolar bone were evaluated quantitatively. Displacement in the palatal direction was observed in the alveolar bone around the incisors and the interdental septum. The displacement and bone remodeling/tooth movement ratio were larger on the labial side than the palatal side, and decreased progressively from the crest to apex level. The bone thickness was significantly increased on the labial side and decreased on the palatal side. Regional differences exist in morphologic changes of the alveolar bone during anterior tooth retraction using TADs. Attention should be paid to the crest region of the palatal alveolar bone because of its small original thickness and low remodeling activity.

Lever arm on bracket vs. lever arm on archwire: A 3D finite element method study of mechanics of miniscrew-supported lingual en-masse retraction of maxillary anterior teeth

To compare the deformation of the main archwire and 3D movements of maxillary anterior teeth during miniscrew-supported en-masse retraction with the lever arm on the archwire and on the brackets in lingual orthodontic treatment in finite element analysis (FEM) simulation. A 3D dental-alveolar model with bonded 0.018×0.025-inch slot lingual brackets and a 0.017×0.025-inch dimension stainless-steel archwire was created. Four FEM models were created based on a 3D dental-alveolar model: in Models A and C, the lever arms were attached to the lingual bracket, while in Models B and D, the lever arms were attached to the archwire. Meanwhile, in Models A and B, the miniscrews were placed in between the molars, while in Models C and D, the miniscrews were positioned on the palatal roof. After a 1.5N retraction force was applied from the miniscrew to the end of the lever arm, the initial movements in the sagittal, transversal, and vertical planes were recorded and analysed for maxillary anterior teeth. In Models B and D, smaller deformation of the main archwire and less prominent bowing effect were noticed in both sagittal and vertical directions compared to their counter groups. In Models C and D, the central incisors showed less torque loss in the sagittal direction and more canine intrusion vertically. For the same lever arm-miniscrew retraction configuration, the lever arm on the bracket showed less deformation of the main archwire and more body movement of the teeth than the lever arm on the archwire group. With the same level arm height, the transverse and vertical bowing effect is reduced when the lever arm was placed distal to the central incisor and the miniscrews placed next to the palatal suture.

Pattern of lip retraction according to the presence of lip incompetence in patients with Class II malocclusion.

The aim of this retrospective study was to compare changes in hard tissue and soft tissue after the four first premolars were extracted with anterior teeth retraction according to the presence or absence of lip incompetence. Patients who underwent the four first premolars were extracted with anterior teeth retraction were divided into competent (n = 20) and incompetent lip (n = 20) groups. Cephalometric measurements for hard tissue and soft tissue changes were performed pre-treatment and post-treatment. In the competent group, the upper and lower lips retreated by 2.88 mm and 4.28 mm, respectively, and in the incompetent group by 4.13 mm and 5.57 mm, respectively; the differences between the two groups were significant (p < 0.05). A strong positive correlation between retraction of the upper lip and upper incisors was observed in both groups (p < 0.05), whereas a correlation between retraction of the lower lip and lower incisors was only found in the incompetent group. A simple linear regression analysis showed that the pattern of lip retraction following the retraction of the anterior teeth was more predictable in the incompetent group than in the competent group. These findings suggest that the initial evaluation of lip incompetence in patients with skeletal Class II is essential for the accurate prediction of the soft tissue changes following retraction of the anterior teeth in premolar extraction treatment. Therefore, sufficient explanation should be provided during patient consultations.

Effects of different designs of orthodontic clear aligners on the maxillary central incisors in the tooth extraction cases: a biomechanical study

BackgroundControlling the 3D movement of central incisors during tooth extraction cases with clear aligners is important but challenging in invisible orthodontic treatment. This study aimed to explore the biomechanical effects of central incisors in tooth extraction cases with clear aligners under different power ridge design schemes and propose appropriate advice for orthodontic clinic.MethodsA series of Finite Element models was constructed to simulate anterior teeth retraction or no retraction with different power ridge designs. These models all consisted of maxillary dentition with extracted first premolars, alveolar bone, periodontal ligaments and clear aligner. And the biomechanical effects were analysed and compared in each model.ResultsFor the model of anterior teeth retraction without power ridge and for the model of anterior teeth no retraction with a single power ridge, the central incisors exhibited crown lingual inclination and relative extrusion. For the model of anterior teeth no retraction with double power ridges, the central incisors tended to have crown labial inclination and relative intrusion. For the model of anterior tooth retraction with double power ridges, the central incisors exhibited a similar trend to the first kind of model, but as the depth of the power ridge increased, there was a gradual decrease in crown retraction value and an increase in crown extrusion value. The simulated results showed that von-Mises stress concentration was observed in the cervical and apical regions of the periodontal ligaments of the central incisors. The clear aligner connection areas of adjacent teeth and power ridge areas also exhibited von-Mises stress concentration and the addition of power ridge caused the clear aligner to spread out on the labial and lingual sides.ConclusionsThe central incisors are prone to losing torque and extruding in tooth extraction cases. Double power ridges have a certain root torque effect when there are no auxiliary designs, but they still cannot rescue tooth inclination during tooth retraction period. For tooth translation, it may be a better clinical procedure to change the one-step aligner design to two-step process: tilting retraction and root control.

Assessment of changes in maxillary dentoalveolar complex following retraction and intrusion of maxillary anterior teeth in mixed Indian population

The biology of tooth movement implies to selective resorption and deposition of the alveolar bone during orthodontic tooth movement. The controversy about "tooth movement through bone" and "tooth movement with bone” is still not settled. The cortices of the alveolar bone are considered boundaries of the alveolar complex that limit the orthodontic tooth movement. The present study evaluated the change in these limits of maxillary dentoalveolar complex post-retraction and intrusion of maxillary anterior teeth.: CBCT data of 15 subjects was assessed to primarily measure the changes in thickness, area and volume of anterior maxillary alveolar bone following retraction &amp; intrusion. As a secondary objective, tooth length was also assessed to ascertain external apical root resorption, post-retraction and intrusion of maxillary anterior teeth. A statistically significant reduction in alveolar bone thickness, mean area and volume on the palatal side was evident and also reduction in tooth length of maxillary central and lateral incisor was observed post retraction and intrusion of maxillary anterior teeth (P-value&amp;#60;0.05). It is essential to evaluate the alveolar housing prior to considering retraction and intrusion of anterior teeth in order to plan appropriate biomechanics and treatment protocol which would minimize iatrogenic side effects and yield a stable treatment outcome.

Temporary anchorage devices and the forces and effects on the dentition and surrounding structures during orthodontic treatment: a scoping review.

Temporary anchorage devices (TADs) offer the clinician an immediate temporary source of skeletal anchorage for a range of orthodontic interventions. It is important to understand forces involved in using TADs and the effects on the dentition and surrounding structures, to improve clinical outcomes. To examine and qualitatively synthesize literature on the forces involved with the use of TADs and the effects on the dentition and surrounding structures in orthodontic tooth movement, to provide better understanding of the complex interactions and the clinical implications. Electronic databases searched included: Cochrane Library [including Central Register of Controlled Trials (CENTRAL)], Embase via OVID, Pubmed, and Scopus. Study screening and selection were conducted in duplicate. Studies selected were clinical studies, simulation studies (computer or laboratory-based), or animal studies with no restriction over gender, age, study type (excluding case reports), or setting. Studies focusing on the forces involved with the use of TADs in orthodontic treatment and their effects on the dentition and surrounding structures were included. A data charting form was piloted and refined. Data charting was performed independently and in duplicate. This consisted of key fields with predetermined options and free text. The extracted data were collated, and a narrative synthesis conducted. The results from 203 included studies were grouped into seven TAD based interventions combining the clinical, simulation, and animal studies. They were: En masse retraction of anterior teeth, intrusion, movement of a single tooth, orthopaedic interventions, distalisation, maxillary expansion and other types. The forces involved with the use of TADs, and their effects on the dentition and surrounding structures, were presented in descriptive and tabular formats. This review restricted study language to English. Formal appraisal of the quality of evidence is not a required feature of scoping reviews, as per the PRISMA-ScR guidelines, however it was evident that a proportion of clinical studies were of high risk of bias and low quality and therefore any proposed changes the reader may consider to their clinical practice should be contextualized in light of this. Across the seven types of TAD based interventions the effects on the dentition and surrounding structures are described providing a better understanding of the complex interactions. A guide to the level and direction of forces in each type of intervention is provided to aid clinicians in achieving high quality outcomes. There is a need to validate future FEA simulation studies by comparing to clinical data. It is also recommended that future scoping reviews incorporate a formal critical appraisal of studies to facilitate the translation of the results into clinical practice. Development of a standard set of terms for TADs is recommended to facilitate future research. Registration of a scoping review is not possible with PROSPERO. None to declare.

A Novel Method to Accelerate Orthodontic Tooth Movement Using Low-Intensity Direct Electrical Current in Patients Requiring en-Masse Retraction of the Upper Anterior Teeth: A Preliminary Clinical Report.

Shortening the duration of orthodontic treatment by speeding up the rate of tooth movement has become an essential goal for both orthodontists and patients. This preliminary report aimed to investigate the safety and effectiveness of a new intraoral removable electrical device in accelerating the en-masse retraction of the upper anterior teeth using low-intensity direct electrical current. This prospective preliminary interventional clinical study was conducted at the Department of Orthodontics, Faculty of Dentistry, Damascus University, Syria, between March 2019 and February 2020. The sample consisted of six patients (four females and two males; mean age: 19.55 ± 0.89 years) whose initial diagnosis was class II division I malocclusion, and their treatment plansuggested the extraction of upper first premolars followed by en-masse retraction. The electrical stimulation was applied on the maxillary anterior region during the en-masse retraction phase using a specially fabricated removable device that was designed by two coauthors of this manuscript (RIS, MYH). Patients were asked to wear their own electrical devices inside their mouths for five hours daily. The primary outcomes were the en-masse retraction rate and duration. The secondary outcomes were safety and patient acceptance. The average total retraction rate during the treatment period was 0.97±0.06 mm/month. The total amount of retraction achieved during follow-up was 5.65 ± 0.85 mm, which was about 91.86% of the space resulting from the extraction of the upper first premolars. The mean treatment duration to complete the en-masse retraction was 5.66±0.81 months. No side effects of the electrical stimulation were found during the follow-up. Low-intensity direct electrical current could be an effective method to accelerate orthodontic movement. The electrical accelerating device used in this study effectively increased the en-masse retraction rate of the upper anterior teeth without any side effects and with high patient acceptance.

Does the aesthetic perception of protrusion correction change if the face is evaluated from the frontal or profile perspectives?

Objective: verify if reduction of facial convexity obtained with dental extractions promotes changes that are noticeable in frontal view. Compare whether the correction of different degrees of protrusion promotes distinct aesthetic perception in frontal and profile analysis. Methods: two brown female patients with dental class I malocclusion, incisors protrusion and convex profile were selected. Patients displayed initially different protrusion magnitude (moderate x excessive) and were both treated with premolars extraction and anterior teeth retraction. Two sets of images were composed enclosing frontal and lateral records at before and after treatment. Sample of 194 laypeople evaluated the images and answered following questions: (1) Can you notice any differences between the correspondent images presented? (yes or no). (2) Which image do you find most attractive? (3) Assign a score for each image from 0 to 10. Results: position of face had an influence on the perception of the moderate protrusion. In this case, less negative impact on aesthetics was evidenced when protrusion was evaluated frontally. In addition, changes resulting from treatment were more noticeable when analyzed from the profile perspective. Regarding excessive protrusion, no significant differences were observed when comparing frontal and profile views, indicating that protrusion and treatment effects can be perceived equally in both views. Conclusions: treatment with dental extractions in patients with moderate protrusion generates impacts that can be more easily noticed in the profile analysis. However, in patients with excessive protrusion, changes promoted by treatment are noticed in frontal analysis in the same way as in profile.

Different biomechanical effects of clear aligners in closing maxillary and mandibular extraction spaces: Finite element analysis

Compared with fixed treatments, clear aligners (CAs) have the advantages of comfort, esthetics, and hygiene, and are popular among patients and orthodontists. However, CAs exhibit control deficiencies in extraction patients because of insufficient root control and retention effects. These deficiencies can magnify biomechanical differences in bimaxillary dentition, further causing different orthodontic requirements between maxillary and mandibular dentition. This study aimed to elaborate on the biomechanical characteristics of bimaxillary dentition in extraction space closure and provided feasible biomechanical compensation strategies for use in clinical practice. We constructed a 3-dimensional (3D) bimaxillary model based on patient data. Several 3D modeling-related software was used to generate a standard first premolar extraction model, CAs, and attachments. Subsequently, finite element analysis was performed to demonstrate the biomechanical effects. The maxillary and mandibular dentition showed a roller coaster effect during space closure. Compared with the maxillary dentition, the mandibular posterior teeth exhibited stronger relative anchorage causing greater anterior teeth retraction. The tipping and vertical movements of the anterior teeth were related to tooth length. The longer the anterior tooth, the less tipping and greater vertical displacement occurred. Generally, when having the same retraction distance, the mandibular dentition exhibited greater retroclination and fewer extrusions. Both mechanical and retention compensations should be considered to prevent these unwanted tipping movements. Adding specific attachments to bimaxillary dentitions compensated for the retention and root control deficiencies of CAs. When applying CAs to extraction patients, different biomechanical effects can present in the bimaxillary dentition because of specific dentition morphologies. To effectively treat these patients, mechanical compensation through overcorrection of the target position should be designed on the basis of bimaxillary control deficiencies, and retention compensation by adding specific attachments should also be considered according to the overcorrections.

Quantitative Evaluation of Pentraxin-3 in Peri-Miniscrew Implant Crevicular Fluid in Patients Undergoing Orthodontic Treatment: A Prospective Study.

To assess the levels of Pentraxin-3 (PTX3) in peri-miniscrew implant crevicular fluid (PMICF) before and after orthodontic force application Material and Methods: This study included 40 miniscrew implants (MSI) sites in 11 orthodontic patients with high arch discrepancy requiring first premolar extraction using maximum anchorage mechanics for the retraction of anterior teeth. After alignment, the en-masse anterior retraction was carried out using the MSI-supported direct anchorage method. PMICF was collected from the crevice of MSI using Periopaper strips 1.2µl (OraflowInc. USA) after one hour, 24 hours, and three weeks of MSI insertion and after one hour, 24 hours, seven days, three weeks, and six weeks of the force application. Samples were quantitatively analyzed for PTX3 levels through enzyme-linked immunosorbent assay (ELISA). The trend in the change of PTX3 levels was evaluated using the Wilcoxon signed-rank test. The mean concentration of PTX3 immediately after MSI insertion was 1.19 ng/ml, significantly higher than after 3 weeks after MSI insertion (0.72 ng/ml), which may correspond to the baseline. After loading, the mean PTX3 concentration increased significantly with the peak at 24 hrs (1.28 ng/ml), followed by a gradual decline till the completion of the study (0.5 ng/ml). After MSI insertion, a rise in PTX3 levels in PMICF suggests an underlying inflammatory process. The slow decline in PTX3 level and return to the baseline after loading suggests an adaptive bone response to the stimulus.