Bimaxillary Protrusion Research Articles

To evaluate the divine proportion on silhouette photographs of skeletal class I bimaxillary protrusion cases treated with first premolar extraction- An in-vitro study

Objectives: The aim of the study is to assess the divine proportion of soft tissues seen in bimaxillary protrusion cases and compare this proportion on pre-treatment and post-treatment Silhouette photographs of skeletal (Sk) Class I bimaxillary protrusion patients treated by premolars extraction. Material and Methods: This research was conducted on 50 samples of pre-treatment along with post-treatment outline form photographs of Sk Class I bimaxillary protrusion patients aged 18–30 years in an orthodontics and dentofacial orthopedics department. The samples had an equal distribution with 25 males and females. All profile photos with Class I bimaxillary protrusion were converted into silhouette form. To assess the divine proportion in patient profiles, each silhouette photograph was marked by five anatomic landmarks, which were as follows: Soft-tissue nasion (N), trichion (Tr), subnasale (Sn), stomion (St), and a soft-tissue menton (Me) which was followed by the measurement of six linear dimensions; ratios were measured as R1, R2, R3, R4, and R5. These ratios of the patient’s profile, both before and after the treatment, were then compared to find out the soft-tissue alterations that have taken place in patients having Class I bimaxillary protrusion corrected by the first four premolars extraction. Results: The findings indicate that all post-treatment proportions in males indicated highly noticeable changes in contrast to pre-treatment ratios. However, females revealed highly noticeable differences in R1, R2, and R4 ratios, statistically evident differences were shown by R3 and R5 ratios in contrast to ratios before the treatment. Thus, the proportions appeared to be closer to the divine proportion. Conclusion: The results showed that all the ratios were found to be closer to divine proportion, and thus, premolars extraction in cases with convex facial form does help us to achieve esthetically pleasing faces.

Interdisciplinary Management of a Class II Bimaxillary Protrusion Case With a Traumatized Maxillary Central Incisor: A Case Report

Interdisciplinary Management of a Class II Bimaxillary Protrusion Case With a Traumatized Maxillary Central Incisor: A Case Report

Comparative evaluation of the position of incisive canal and its proximity to the maxillary central incisor roots with different incisor inclinations – A CBCT study

Objectives: The aim of this study was to evaluate and compare the incisive canal position and its proximity to maxillary central incisor roots at different incisor inclinations. Material and Methods: A 105 CBCT samples have been then divided into three groups on the basis of U1-SN and U1-NA when traced on lateral cephalogram into normal, proclined, and retroclined. Several linear measurements have been made in the axial plane at three different levels, that are palatal opening, mid-root level, and apex, in relation to the incisive canal. Angular measurements were also made in the sagittal plane. Results: A significant difference was found between the proximity of the maxillary right and left central incisor to the incisive canal in the proclined and retroclined group at the mid-root level and at the apex. There has been a major variation between the angles developed by the incisive canal to the palatal plane in all three groups. A significant correlation was also found between the angle formed by the incisive canal to the palatal plane and the tooth’s long axis to the palatal plane. Conclusion: The proclined group exhibits the shortest distance between the incisive canal and the incisors, implying the need for meticulous planning in Class II Division 1 and bimaxillary protrusion cases. This planning is crucial when aiming for extensive retraction and intrusion to prevent any contact with an incisive canal, thus reducing the root resorption risk.

Evaluation of Rate of Space Closure Between Platelet Rich Plasma (Prp) Injection and Piezocision in Bimaxillary Protrusion Cases

Aim: Reducing orthodontic treatment duration is a significant concern for both patients and clinicians, as prolonged treatments can lead to complications like dental caries, root resorption, and decreased patient compliance. This study aims to compare the effectiveness of two minimally invasive techniques—Piezocision and platelet-rich plasma (PRP) injection—in accelerating orthodontic tooth movement during space closure in patients with bimaxillary protrusion. Methods: Sixteen patients diagnosed with Angle's Class I bimaxillary protrusion requiring extraction of first premolars were randomly assigned to two groups. Group A (n = 8) underwent Piezocision-assisted orthodontic treatment, while Group B (n = 8) received submucosal PRP injections. In both groups, one side of the maxillary arch served as the experimental side, and the contralateral side served as the control. Measurements of space closure were taken at the initiation of retraction (T₀) and after 90 days (T₁). Results: Both Piezocision and PRP significantly enhanced the rate of space closure compared to their control sides. However, Piezocision demonstrated a statistically faster rate of tooth movement than PRP injection. The mean difference in space closure between the Piezocision and PRP groups at T₁ was significant (p < 0.001). Conclusion: While both Piezocision and PRP injections effectively accelerated orthodontic tooth movement, Piezocision proved to be more efficient in reducing treatment time. Clinicians may consider Piezocision as a preferred method for patients seeking expedited orthodontic treatment.

Anchorage loss of the posterior teeth under different extraction patterns in maxillary and mandibular arches using clear aligner: a finite element study

BackgroundExtracting the premolars is an effective strategy for patients with bimaxillary dentoalveolar protrusion. Clear aligners (CAs) close the extraction spaces through shortening the length of aligners. The contraction force generated by the terminal of aligners makes the posterior teeth tip mesially, which is known as the roller coaster effect. This phenomenon is even worse in the 2nd premolar extraction cases. Posterior anchorage preparation is commonly used to protect the angulation of molars, taking the form of presetting distal tipping value. However, the distal tipping design aggravates the anchorage loss of anterior teeth simultaneously. This study aimed to explore the different anchorage loss of the posterior teeth when the 1st or 2nd premolars were extracted using CAs, respectively in maxillary and mandibular arches, further providing guidance for anchorage preparation design in clinical practice.MethodsTwo bimaxillary finite element models with different extraction patterns were established to simulate the anterior en-masse retraction process of the CAs. In Model 1, the maxillary and mandibular 1st premolars were extracted, while in Model 2, the 2nd premolars were extracted. Finite element analysis methods were utilized to analyze the tipping angle of the anterior and posterior teeth.ResultsCompared between two models, the anterior teeth exhibited a greater lingual inclination tendency and the posterior teeth exhibited a slighter mesial tipping tendency in Model 1 regarding individual tooth. The closer to the extraction spaces, the greater the tip, and the distal tipping tendency of the 1st premolars was more evident than the mesial tipping tendency of the 1st molars in Model 2. Compared between the maxillary and mandibular arches, the mesial tipping tendency of individual posterior tooth was more evident in the maxilla. In addition, the highest hydrostatic stress of the periodontal ligaments was concentrated on the cervical and apical parts directly adjacent to the extraction spaces, and it exhibited relatively uniform distribution in Model 1.ConclusionsThe individual posterior tooth showed the same mesial tipping direction but to different degree when the 1st or the 2nd premolars were extracted during clear aligner treatment. Presetting anchorage preparation design for the posterior teeth is essential to alleviate the roller coaster effect, especially in the 2nd premolar extraction cases. Furthermore, larger anchorage preparation value should be proposed for the maxillary posterior teeth.

A Comparative Study of Traditional and Computer-aided Surgical Simulation Guides in Orthognathic Correction of Bimaxillary Protrusion.

To compare the efficacy of traditional occlusal guides with computer-aided surgical simulation (CASS) guides in enhancing postoperative outcomes for patients with bimaxillary protrusion. This retrospective study evaluated 34 patients undergoing anterior maxillary and mandibular subapical osteotomy at the Plastic Surgery Hospital of the Chinese Academy of Medical Sciences. Fourteen patients were treated using traditional occlusal guides, whereas 20 patients were treated with CASS guides (median age 28.6 years, median follow-up 259 days). Pre and postoperative cephalometric indicators were measured using cephalometric software. Data analysis was conducted using SPSS 14.0, with significant differences determined at P < 0.05. All 34 patients experienced primary healing without complications. Follow-up indicated significant improvements in key cephalometric measurements in the CASS group compared with the traditional group, including mandibular position (SNB angle, P < 0.001), jaw relationship (ANB angle, P < 0.001), facial angle (FH-NPo, P = 0.002), and condyle-to-sella distance (Co-S, P = 0.024). The CASS group also showed better aesthetic outcomes, with significant reductions in overjet (P = 0.012), overbite (P = 0.001), and improved alignment of upper and lower incisors (U1-L1 angle, P = 0.031). CASS-guided surgery offers a superior alternative to traditional methods for treating bimaxillary protrusion, providing more precise and aesthetically pleasing results. This study highlights the significant advantages of using advanced digital simulation and 3-dimensional printing technologies in orthognathic surgery.

Changes in the curvature of upper and lower lips following the first premolar extraction in Class I bimaxillary protrusion - A cephalometric study

Bimaxillary dentoalveolar protrusion is a condition characterized by protrusion of the maxillary and mandibular incisors with increased procumbency of the lips. The treatment of choice for these patients is fixed orthodontic treatment after extraction of four first premolars. This treatment would result in the retraction of anterior teeth with a resultant decrease in soft tissue convexity. Objective of the study is to find out how the curvature of upper and lower lip change following fixed appliance therapy in patients with class I Bimaxillary protrusion following extraction of first premolars. A total of 32 subjects, 13 males and 19 females in the age group of 13-21 years diagnosed with BMP were included in the study. Pre-treatment and post-treatment cephalograms were obtained from subjects satisfying the inclusion and exclusion criteria. Cephalometric landmarks, lines used in the study were marked and analysed. The soft tissue parameters were measured and compared using paired t test and Pearson’s correlation coefficient. The overall effect of orthodontic correction of bimaxillary protrusion from subjects were analysed by evaluating the soft tissue changes between pre-treatment and post treatment cephalometric radiographs. There is a statistically significant difference with decrease in ULST, B`-PM line, B`-LiPog`, A`-PM line, LLIT, LLVT, Pog-Pog` and no statistically significant difference in A`-NtLs and ULVT. The results showed a reduction in lip procumbency. Among the soft tissue parameter studied, there is a statistically significant decrease observed for ULST, B`-PM line, B`-LiPog`, A`-PM line, LLIT, LLVT and Pog-Pog`.

Position and root resorption of the incisors following anterior segment retraction using friction versus frictionless mechanics: A randomised controlled trial.

To evaluate the three-dimensional position and root resorption of incisors after anterior segment retraction (ASR) using friction versus frictionless mechanics. Thirty female patients (13-18 years) with bimaxillary protrusion were randomly allocated into two groups. In the intervention group, ASR was undertaken using an elastomeric chain rendering 160 g/side extending between mini-screw implant and a hook crimped on 0.017 × 0.025-inch stainless-steel wire distal to the lateral incisor. In the comparison group, ASR was undertaken using closing T-loops fabricated from 0.017 × 0.025-inch titanium molybdenum alloy (TMA) wire rendering comparable retraction force. In both groups, the canine brackets were ligated after retraction to the mini-screw implants that were inserted in both the upper and lower arches bilaterally. The primary outcome was the three-dimensional changes in the position of the incisors. The secondary outcome was root resorption. These were measured from cone-beam computed tomography scans. Statistically significant decreases in the upper (UI) and lower incisors (LI) crown torque were seen in both groups; however, the difference between groups was not statistically or clinically significant (UI MD -2.04°; 95% confidence interval [CI] = -8.02-3.95; LI MD -0.49°; 95% CI = -7.06-6.08). Significant tipping of upper (MD -1.17°; 95% CI = -2.06--0.27) and lower (MD -1.13°; 95% CI = -1.66--0.60) incisors was found in the friction, but not the frictionless group after retraction; however, the changes were not clinically significant. Significant lower incisor intrusion was found in both groups after retraction; however, the difference between groups was not statistically or clinically significant (MD -0.61°; 95% CI = -1.99-0.77). Statistically significant decreases in the UI and LI root length were seen in both groups. The difference between groups for UI changes was statistically significant (MD 0.54 mm; 95% CI = -0.02-1.07) but probably not clinically significant. Considering the limitations in the current study, there was no advantage of either mechanics over the other regarding the final position of incisors. The likelihood of root resorption should be considered when frictionless mechanics are used for retraction of incisors. Clinicaltrials.gov (NCT04878939).

Friction versus frictionless mechanics during maxillary en-masse retraction in adult patients with Class I bimaxillary dentoalveolar protrusion: a randomized clinical trial.

Extraction space closure is a challenging phase during orthodontic treatment that affects not only the total treatment duration but also the whole treatment outcome. To compare the efficiency of friction and frictionless mechanics during en-masse retraction of maxillary anterior teeth in adult patients with bimaxillary dentoalveolar protrusion. Two-arm parallel group, single-center randomized clinical trial. Thirty-two adult patients with bimaxillary protrusion were recruited and randomly allocated to two different retraction mechanics. A friction group, using NiTi coil springs and a frictionless group using closing T-loops for en-masse retraction. Randomization in a 1:1 ratio was generated by Microsoft Excel. The randomization numbers were secured in opaque sealed envelopes for allocation concealment. Retraction started in all patients following first premolars extraction using miniscrews as a source of indirect anchorage. Activation was done on a monthly basis until complete retraction of anterior segment. The rate of retraction, amount of anchorage loss, the dental, and soft tissue changes were analyzed on digital models and lateral cephalograms taken before retraction and after space closure. The outcome assessor was blinded through data concealment during assessment. Two patients were lost to follow up, so 30 patients completed the trial. The rate of anterior segment retraction was 0.88 ± 0.66mm/month in the frictionless group compared to 0.72 ± 0.36mm/month in the friction group which was statistically significant. Anchorage loss of 1.18 ± 0.72mm in the friction group compared to 1.29 ± 0.55 mm in the frictionless group with no significant difference. Comparable dental and soft tissue changes following en-masse retraction were reported in both groups, with no statistically significant difference. one patient complained of soft tissue swelling following miniscrew insertion, but the swelling disappeared after one week of using mouth wash. The study focused only on the maxillary arch. Both mechanics have successfully achieved the required treatment objectives in patients with bimaxillary dentoalveolar protrusion. Frictionless group showed a faster rate of retraction than the friction group, which was statistically but not clinically significant. Clinicaltrials.gov with the identifier NCT03261024.

Craniofacial and Airway Morphology in Down Syndrome: A Cone Beam Computed Tomography Case Series Evaluation.

Background: Down syndrome (DS) is a genetic condition characterized by an extra copy of chromosome 21, resulting in various physical and cognitive features. This study aimed to comprehensively analyze the dental and craniofacial morphology of individuals with DS using Cone Beam Computed Tomography (CBCT). Methods: Six individuals with DS, comprising five males and one female aged 17 to 35 years, underwent CBCT scanning. Radiographic assessments included dentition, occlusion, paranasal sinuses, airway, skull bones, and suture calcification. Linear and angular cephalometric measurements were performed, and airway analysis was conducted using Dolphin 3D imaging software v.11. Results: The study revealed prognathic maxilla in five patients, prognathic mandible in four, and bimaxillary protrusion in two. Dental findings included microdontia, enamel hypoplasia, and congenitally missing teeth, with maxillary and mandibular third molars most commonly absent. Sinus abnormalities, delayed suture closure, and cervical spine anomalies were also observed. Conclusion: These findings contribute to a deeper understanding of DS-related craniofacial characteristics and emphasize the importance of considering these morphometric features in clinical management strategies for individuals with DS. This study's limited sample size underscores the significance of radiographic assessment in planning interventions such as cosmetic reconstructions, prosthetic rehabilitation, or orthodontic treatment for individuals with DS.

Cone-Beam Computed Tomography Study of Incisive Canal and Maxillary Central Incisors in Dravidian Population.

En-masse maxillary anterior retraction is necessary to attain an esthetic profile in Angle's class I bimaxillary dentoalveolar protrusion and Angle's class II division 1 malocclusion. The objective of this study was to evaluate configurational relationships between maxillary incisors and incisive canal in Angle's class I bialveolar protrusion and Angle's class II division 1 malocclusionby cone-beam computed tomography (CBCT). A total of 108 adult CBCT scans of 54-skeletal class I bialveolar protrusion and 54-skeletal class II division 1 malocclusions were retrospectively analyzed. Angles between palatal plane and axis of maxillary alveolar border (θ1),incisive canal (θ2), and maxillary right central incisor (θ3) were measured in relation to the midsagittal plane. Linear measurements such as incisive canal width (IC-IC), medial inter-root distance (Rm-Rm), posterior inter-root distance (Rp-Rp), anteroposterior distance from Rm to tangent of right central incisor (11 Rm-Cat), and left central incisor (21 Rm-Cat)corresponding to three vertical levels (L1, L2, and L3) were assessed in axial cross-sectional plane. Association among angular measurements was examined by Spearman correlation coefficient analysis. Mann-Whitney U test compared variables of linear measurements at three vertical levels. Estimated distance from incisor root to incisive canal was 5-6 mm in both groups slightly influenced by skeletal class and vertical levels but not gender. Mann-Whitney test demonstrated significant differences between groups at three vertical levels (p<0.05). Only θ2 revealed a significant difference (p<0.05) between malocclusions compared to θ1 and θ3. The angular measurements for both malocclusions were positively correlated (p<0.05). Sagittal root-canal cortical plate distance varied significantly in both malocclusions (5-6 mm). Inter-root distance (Rp-Rp) was greater than incisive canal width (IC-IC) at all three vertical levels indicating a reduced possibility of canal invasion after maximum retraction at posterior levels.

Use of Orthodontic Mini-Implants in Conjunction with Elastics for Extrusion of Impacted Canines and Correction of Bimaxillary Protrusion.

Orthodontic extrusion of canines, although challenging, can yield excellent results without tooth extraction. Temporary anchorage devices (TADs), involving mini-implants in the alveolar bone, offer stable anchorage via biomechanics. This case report details orthodontic extrusion of bilaterally impacted maxillary canines using TAD mini-implants and elastics. The patient had bimaxillary protrusion, moderate crowding, deep bite, and vertical growth pattern, necessitating careful treatment planning. The combination of TAD mini-implants with Class-II elastics simplified biomechanics. The treatment achieved efficient results, maintained adjacent teeth positioning, and improved patient compliance.

Modified single rigid vacuum-formed indirect bonding trays for lingual bracket application: a case report

Abstract Lingual orthodontic treatment offers an aesthetic alternative but presents unique challenges in bracket positioning. The present article introduces a modified design and fabrication process for rigid vacuum-formed indirect bonding trays for lingual bracket application. The technique is presented through a clinical case report of an adult patient who presented with bimaxillary dentoalveolar protrusion and managed using lingual appliances, premolar extractions, and mini-screws. The modified rigid vacuum-formed trays enabled the accurate simultaneous bonding of multiple teeth as well as individual teeth. The technique offers several advantages over existing indirect bonding methods, including time-saving, simplicity, easy removal of excessive adhesive, and potential cost-effectiveness. The superimposition of post-bonding scans and the digital orthodontic setup showed high agreement between the planned and actual bracket positions. Additionally, the close alignment between the planned orthodontic setup and the achieved treatment outcome highlights the reliability of the technique for predictable lingual orthodontic treatment. Further clinical studies with larger sample sizes are needed to confirm the effectiveness of this technique.

Effect of low-level laser therapy on en masse retraction in females with bimaxillary dentoalveolar protrusion : A single-center randomized clinical trial.

Acceleration of tooth movement has gained remarkable attention during the last decade. The aim of this study was to evaluate the effect of low-level laser therapy (LLLT) on en masse retraction of upper anterior teeth in adult women with bimaxillary dentoalveolar protrusion. In this two-arm parallel trial, 36women with bimaxillary dentoalveolar protrusion were randomly divided into two equal groups. Eligibility criteria included classI Angle molar relationship, good general and oral health as well as no systemic disease or syndrome. Four temporary anchorage devices (TADs) were used in the upper and lower arches for anchorage purposes. A 0.019×0.025-inch stainless steel wire with crimped hooks just distal to the maxillary canines was inserted. Nickle titanium (NiTi) closed coil springs (200 g/side) were employed for en masse retraction following extraction of the first premolars. In the laser group (LG), retraction of the upper anterior teeth was done along with the application of LLLT on days0, 3, 7, and 14 after extraction and then repeated biweekly until the end of retraction. Retraction was completed without LLLT application in the nonlaser group (NLG). Data concerning the rate of retraction as well as first molars and anterior positional changes were gained from digitized models and cone beam computed tomography (CBCT) scans taken just before extraction and at the end of retraction. Treatment-associated pain and root resorption were evaluated using visual analogue scale (VAS) and CBCT scans, respectively. Four patients dropped out prior to follow-up. The duration of retraction was 10.125 ± 2.876 and 13.643 ± 3.455 months in the LG and NLG, respectively. The LG showed astatistically significant faster rate of en masse retraction (0.833 ± 0.371 mm/month) compared to the NLG (0.526 ± 0.268 mm/month; P ≤ 0.035). The observed root resorption was significantly less in the LG (P ≤ 0.05) with comparable pain scores in both groups. Within the constraints of the parameters of the LLLT used in the current study and despite the statistically significant results on the rate of en masse retraction and the associated root resorption, LLLT did not demonstrate aclinically relevant effect that justifies its use to enhance en masse retraction. Clinicaltrials.gov TRIAL REGISTRATION NUMBER: NCT05183451 DATE OF REGISTRATION: January10, 2022, "Retrospectively registered" URL OF TRIAL REGISTRY RECORD: https://www. gov/study/NCT05183451.

The Risks Behind Fixed Retainers After Orthodontic Treatment.

Bonded fixed retainers are frequently used nowadays as the main and often the only retention protocol after orthodontic treatment. The expectations for long-lasting lifetime stability of the occlusion led orthodontists to seek the ultimate retention protocol with minimal patient compliance. Fixed retainers have many disadvantages and risks that should be considered in advance. Different failures of fixed retainers are described and categorized. The workflow for the retreatment of relapse caused in spite of the fixed retainers is described with 3 case presentations: Open bite, Root movement and Bimaxillary protrusion, all treated with clear aligner treatment (CAT). A revised retention protocol is suggested.

Management of Unilateral Impacted Maxillary Permanent Canine: A Case Report

Introduction The management of maxillary canine is very complex because it must be carefully planned and carried out as a team. The handling of impacted canine cases must be seen from a clinical and radiological point of view. Maxillary canine impaction can be caused by a lack of space or inadequate seed placement. The time to treat canine impaction is usually between the ages of 11 and 14. Objective The aim of this case report was to describe the management of an impacted maxillary left canine of a teenage girl. Successful treatment requires complete diagnostics, such as radiographs, good teamwork, and precise treatment planning of the dental team. Case Report An 11-year-old female patient with class I molar relationship, bimaxillary protrusive, and impacted left upper canine visited the clinic for orthodontic treatment. Extraction of four first premolars (bicuspids) was carried out, and exposure by the periodontist was completed on the maxillary left canine for the installation of a traction device (gold chain traction). Conclusion The appropriate timing, treatment plan, and proper surgical exposure preparation in handling this case produced optimal and ideal results.

Effectiveness of autologous leukocyte-platelet-rich fibrin on the rate of maxillary canine retraction, rotation, pain, and soft tissue healing: A split-mouth randomized controlled trial.

To assess the effectiveness of leukocyte-platelet-rich fibrin (L-PRF) compared with conventional treatment on canine retraction, rotation, pain, and soft tissue healing. Sixteen adult patients aged 18-25 years (10 females, and 6 males; mean age 22.25 ± 2.26 years) with Class I bimaxillary protrusion and Class II div 1 malocclusion participated in this single-center, split-mouth randomized controlled trial at the Orthodontics Department of a single hospital in SCB Dental College and Hospital, Cuttack, India. Randomization was performed using a computer-assisted function with a 1:1 allocation ratio. The intervention included the placement of L-PRF on the experimental side and follow-up for 90 days. The primary outcome measures were canine retraction, rotation, pain, and soft tissue healing. The range of tooth movement was evaluated at 15-day intervals: 0th day (T0), 15th day (T1), 30th day (T2), 45th day (T3), 60th day (T4), 75th day (T5), and 90th day (T6). Canine rotation was assessed at T0 and T6, and pain and soft tissue healing were evaluated on the 3rd, 7th, and 15th days of the treatment. Cumulatively, the L-PRF group demonstrated a significantly greater tooth movement as compared to conventional treatment group (P < 0.001). Overall, canine retraction was 1.5 times greater on the L-PRF side than on the control side. Canine rotation showed no significant relationship, whereas pain and soft tissue healing were significantly better on the L-PRF side than on the control side. Local administration of L-PRF amplifies canine retraction while improving pain and soft tissue repair.

Evaluation of anchorage loss after en masse retraction in orthodontic patients with maxillary protrusion using friction vs frictionless mechanics: randomized clinical trial.

To evaluate anchorage loss after en masse retraction in bimaxillary dentoalveolar protrusion patients using friction vs frictionless mechanics. Thirty patients with bimaxillary dentoalveolar protrusion needing extraction of upper first premolars and en masse retraction with maximum anchorage were included in this two-arm, parallel, single-center, single-blinded randomized clinical trial with a 1:1 allocation ratio using fully sealed opaque envelopes. Friction group retraction utilized elastomeric power chain between miniscrews and hooks crimped mesial to upper canines on 17 × 25 stainless steel archwire. Frictionless group used customized T-loop springs loading upper first molars indirectly anchored to miniscrews. Activation was every 4 weeks until full retraction. The primary outcome assessed was anchorage loss evaluated at cusp tip and root apex of the first molar. First molar rotation, incisor tip and torque, and root resorption of anterior teeth were evaluated on digital models and cone beam computed tomography taken before and after space closure. Anchorage loss at crown of first molar was significantly more in frictionless group by 2.1 mm (95% CI = -0.4 to 3.5), (P = .014), while there was no significant difference in anchorage loss at root apex between groups. Significant mesial in molar rotation of 6.672° (95% CI = 12.2-21.2), (P = 0.02) was greater in the frictionless group. Both groups showed comparable tip, torque, and root resorption values. No severe harms were reported. There was mild gingival overgrowth and inflammation in the frictionless group due to T-loop irritation. Extra anchorage considerations are needed during en masse retraction when frictionless mechanics is implemented as higher anchorage loss and molar rotation were detected. No difference in tip, torque, and root resorption was observed.

Efficiency of friction versus frictionless mechanics for correcting bimaxillary dentoalveolar protrusion in dizygotic twins – A case report

The purpose of this case presentation is to determine the efficiency of two treatment mechanics in correcting clinically comparable malocclusion in dizygotic twins. The case report describes the orthodontic management of 19-year-old non-identical twins diagnosed with bimaxillary dentoalveolar protrusion on a Class I skeletal base with severe crowding using two different treatment mechanics. The first patient was treated with frictionless mechanics by making use of Kalra simultaneous intrusion and retraction arch for space closure, whereas the friction mechanics accomplished the task in the second patient with mini-implant (Titanium mini-implant, FavAnchor™ SAS, Favorite supplies, Thane west, Maharashtra, India) assisted power arm (Power hook, Azdent Orthodontics, Zhengzhou, China) retraction. It evaluated the overall treatment duration, anterior torque control, and level of comfort for the patients with the two mechanics. The post-treatment results in both cases exhibited remarkable change in inclination of upper anterior teeth which were established through cephalometric findings. Moreover, the anterior torque control was comparatively superior with loop mechanics over mini-implant assisted sliding mechanics. Both the treatment mechanics effectively and efficiently corrected the malocclusion with considerable impact on soft-tissue profile.

Incisor and Soft Tissue Characteristics of Adult Bimaxillary Protrusion Patients among Different Skeletal Anteroposterior Classifications.

The objective of this study was to investigate the upper incisors (U1), lower incisors (L1), and soft tissue profiles of bimaxillary protrusion (BM) adult patients among skeletal Class I (BM1), II (BM2) and III (BM3). Understanding these characteristics would be useful for incisor and lip diagnostics in different skeletal classifications. Fourteen linear and twelve angular variables of the incisors and lips were evaluated in 214 lateral cephalograms (BM1 = 91, BM2 = 84, BM3 = 39). ANOVA and Bonferroni tests compared the measurements. BM1 and BM3 exhibited a greater U1 position and U1 inclination than the norms, while BM2 presented only a greater U1 position than the norms but normal U1 inclination. BM1 and BM3 had a significantly greater U1 position than BM2. BM1 and BM2 demonstrated a greater L1 position and L1 inclination than the norms, whereas BM3 displayed only a greater L1 position than the norms but normal L1 inclination. BM2 had the most anterior L1 position, whereas BM3 had the least anterior position. Only BM2 had a longer anterior dental height (ADH) than the norms, while BM1 and BM3 had a normal ADH and the significantly shortest ADH, respectively. Only BM1 had a normal upper incisor display at rest (U1R), while BM2 and BM3 displayed an increased and decreased U1R, respectively, with significant differences among the three groups. The most significantly protruded upper and lower lips were presented in BM2, but these were exhibited the least in BM3. The most significant acute nasolabial angle (NLA) was found in BM3, whereas BM2 presented the least acute NLA. A normal lip-chin-throat angle (LCTA) was observed in BM1 and BM3, while only BM2 had a greater LCTA than the norms. The most significant obtuse LCTA was found in BM2, while BM3 had the least obtuse LCTA. Therefore, both U1 and L1 in all groups presented protrusion and proclination, except for U1 in BM2, while L1 in BM3 exhibited normal inclination. The ADH and U1R were increased in BM2 but decreased in BM3. The most acute NLA was found in BM3, whereas the least acute was found in BM2. The most obtuse LCTA was in BM2, while the least was in BM3.