Extraction Space Closure Research Articles

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.

Management of anchor loss with the use of infrazygomatic implants – A case series

The mesial tipping of the first molar marks the onset of anchorage loss, and changes in the angulation of the first molar are closely related to anchorage loss. Despite the various treatment strategy, different patients show different tendencies towards anchorage loss, which influences the treatment results and must be managed. The quest for search for an ideal intraoral anchorage device has led orthodontists to micro-implants or temporary anchorage devices (TADs), which offer to solve one of the greatest dilemmas of “anchorage control. The use of miniscrews has been increased recently due to their ease of insertion and removal, reasonable cost, biocompatibility and capability to withstand orthodontic forces The introduction of the mini screw and infrazygomatic implant has provided orthodontists with a solution to the significant challenge of "anchorage control." This case series describes the successful management of anchor loss with the infrazygomatic implant(IZC) that occurred during premolar extraction space closure in a Class I and Class II malocclusion patients with severely proclined maxillary incisors.

The effect of enhanced structure in the posterior segment of clear aligners during anterior retraction: a three-dimensional finite element and experimental model analysis

BackgroundMesial tipping of posterior teeth occurs frequently during space closure with clear aligners (CAs). In this study, we proposed a new modification of CA by localized thickening of the aligner to form the enhanced structure and investigate its biomechanical effect during anterior retraction.MethodsTwo methods were employed in this study. First, a finite element (FE) model was constructed, which included alveolar bone, the first premolars extracted maxillary dentition, periodontal ligaments (PDL), attachments and aligners. The second method involved an experimental model—a measuring device using multi-axis transducers and vacuum thermoforming aligners. Two groups were formed: (1) The control group used common CAs and (2) the enhanced structure group used partially thickened CAs.ResultsFE model revealed that the enhanced structure improved the biomechanics during anterior retraction. Specifically, the second premolar, which had a smaller PDL area, experienced a smaller protraction force and moment, making it less likely to tip mesially. In the same vein, the molars could resist movement due to their larger PDL area even though they were applied larger forces. The resultant force of the posterior tooth was closer to the center of resistance, reducing the tipping moment. The canine was applied a larger retraction force and moment, resulting in sufficient retraction of anterior teeth. The experimental model demonstrated a similar trend in force variation as the FE model.ConclusionsEnhanced structure allowed force distribution more in accordance with optimal principles of biomechanics during the extraction space closure while permitting less mesial tipping and anchorage loss of posterior teeth and better retraction of anterior teeth. Thus, enhanced structure alleviated the roller coaster effect associated with extraction cases and offered a new possibility for anchorage reinforcement in clear aligner therapy.

Dynamic biomechanical changes of clear aligners during extraction space closure: Finite element analysis

Clear aligners (CAs) have recently become popular and widely used orthodontic appliances. Research on CA biomechanics has become a focal point in orthodontics to improve the efficiency of CA treatment and address challenging issues, such as extraction. The biomechanical characteristics of CAs in space closure have been reported. However, previous studies have mainly focused on static biomechanical analysis that cannot demonstrate the dynamic biomechanical changes in CAs during space-closing. Given that these biomechanical changes can be significant and have considerable clinical value, this study aimed to investigate these characteristics. Sequential extraction space-closing models were derived from included patient data and refined using modeling and CA design software. A finite element analysis was performed to obtain biomechanical raw data. This study introduced a dual coordinate system and space geometry analysis to demonstrate the biomechanical properties accurately. As space closure progressed, the instantaneous tooth displacements increased, indicating an enhanced space closure force because of the increased strain in the CA extraction area. Meanwhile, the central axis of rotation of the anterior teeth continuously moved toward the labial-apical direction, showing a gradually enhanced vertical and torque control effect. During space closure, CAs undergo specific biomechanical changes, including increased contraction and control forces on both sides of the gap. These biomechanical effects are beneficial to alleviate the roller coaster effect gradually. Meanwhile, more reasonable staging design strategies can be proposed on the basis of this biomechanical mechanism.

Characterizing orthodontic tooth movement in real time using dental monitoring scans: A pilot study.

This pilot study aimed to quantify the magnitude and type of tooth movement occurring in short time intervals within the regular monthly orthodontic visits for patients with fixed appliances and undergoing maxillary canine retraction. Additionally, this pilot study aimed to provide a descriptive evaluation for the accuracy and reliability of the Dental Monitoring (DM)-captured scans to those of an iTero digital scans in an extraction space closure model. 3D intraoral photographic scans (DM) for 12 patients with maxillary first premolar extractions in a single-centre academic institution. Twelve patients treated with fixed appliances and undergoing space closure for maxillary premolar extraction(s) were included. Nickel-titanium (200 g) closing coil springs were used for canine retraction. At initiation of space closure (T1), iTero scans were acquired, and patients were instructed to take DM scans every 4-5 days until their next visit in 4-5 weeks (T2). At T2, a final iTero scan in addition to a DM scan was taken. The number of patients who did the scans regularly as instructed declined as time elapsed. Stereolithography (STL) files generated from the DM scans were superimposed with the STL files from the iTero scans using GOM Inspect software to determine the accuracy of the DM 3D models. To assess rate, type and direction of tooth movement, each of the 3D image STL files generated from the DM scans, taken every 4-5 days by each patient, was superimposed on the previously captured scan. The rate of tooth movement for the maxillary molars and canines was calculated in the 3 planes of space (X, Y, Z) at each time point, until the end of the experiment. Preliminary results indicated that the maxillary canines appeared to be displaced the greatest amount in the first 4-5 days with initial distolateral movement. As time elapsed, the rate of tooth movement decreased, and the tooth started moving distolingually. Dental monitoring software provides a high-tech platform to monitor tooth movement in a 'real-time' approach. Accuracy of the photographic scans in relationship to the intraoral scans appears promising. There seems to be some evidence that the greatest amount of movement occurs initially in the first few days after activation, dropping thereafter to become a slower constant rate of tooth movement.

Alveolar bone loss and root resorption in mesialized second molars in mandibular first molar extraction cases as compared to contralateral non-extraction side in young adults: A retrospective cross-sectional study

The alveolar bone loss (ABL) and external apical root resorption (EARR) depict the safety of mesialization of mandibular second molars into the extraction space of mandibular first molars. The aim of this study was to evaluate the ABL and EARR after closure of mandibular first molar extraction space by mesialization of second molar on extraction side (ES) as compared to the contralateral non-extraction side (NES). A retrospective cross-sectional study was carried out using the pre and posttreatment orthodontic records of young adults with complete set of permanent dentitions treated with extraction of unilateral mandibular first molar and non-extraction treatment on the contralateral side. All patients underwent mini-implant supported mesialization of second molar on ES. The ABL and EARR of second molar on ES and contralateral NES were measured on digital orthopantomograms. The ABL and EARR of second molars on ES and contralateral NES were compared using independent sample t-test. A total of 36 subjects (14 males and 22 females) were included in the study. The mean treatment duration for molar mesialization was 28.75±8.05months. The mean crown and root movements of mandibular second molar on ES were 10.94±1.25mm and 9.04mm±1.14mm, as compared to 0.91±1.01mm and 0.77±0.83mm on contralateral NES, respectively. The mean ABL and EARR at mandibular second molar were found to be significantly greater on the ES than the contralateral NES (P<0.001 and<0.05, respectively). A total of seven patients (19.4%) experienced ABL≥1mm on ES as compared to none in the contralateral NES. EARR of>2mm of at least one root was found in seven patients (19.4%) in ES as compared to four (11%) in contralateral NES. There was small but statistically significant difference in the ABL and EARR of mesialized mandibular second molar at first molar ES as compared to the contralateral NES. For majority of patients this difference was small but few isolated cases experienced severe ABL and EARR.

Closure of first molar extraction spaces and correction of Class II malocclusion using anterior bite turbo and Class II elastics: A case report

At present, orthodontists are treating more adult patients with missing or hopeless first molars as these teeth have the highest incidence of decay in permanent dentition. This case report presented the closure of extraction spaces of four first molars in a patient with Class II malocclusion. High torque self-ligating brackets were used combined with anterior bite turbo and Class II elastics. According to the case report, the combination of anterior bite turbo and Class II elastics may have the possibility to correct bite deepening during space closure and allow further upper incisor retraction and Class II correction.

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.

Efficacy of various Platelet concentrates on the rate of Orthodontic tooth movement – A Systematic Review and Meta-Analysis.

With increased interest in reducing the average duration of Orthodontic treatment, various techniques for accelerating tooth movement have been extensively researched. Studies have shown conflicting results with various Platelet Concentrates (PCs). Hence this review aimed to evaluate and gather evidence of the effectiveness of Platelet concentrates (PRP/PRF) during orthodontic extraction space closure about the space closure rate and the time required for and the angular measurements of the tooth movement during space closure. The electronic databases of Cochrane CENTRAL, PubMed, Scopus, Web of Science, Embase, and Google Scholar were searched up to June 2021. The criteria for selection were Randomised Controlled Trials (RCTs) comparing the use of PCs with that of no intervention/placebo during canine retraction or retraction of anterior teeth. All other studies were excluded. Two reviewers performed the entire process of study selection, extraction of data, and quality assessment independently. Cochrane's ROB2 tool was used for quality assessment in the studies selected. The quantitative analysis of the studies was performed with the use of Review Manager (RevMan5). Eight RCTs met the inclusion criteria and were included for the qualitative synthesis in this review. Of these, five RCTs were included in the quantitative analysis. The results indicated an insignificant increase in the rate of tooth movement with the administration of the PCs (0.13 mm more Tooth movement; 95% CI = -0.17 – 0.43; p = 0.40). No differences were also found in the change of canine inclination and amount of canine rotation. Quantitative synthesis of the selected five studies (3 studies had a low Risk of Bias) reveals no statistically significant difference in the rate of tooth movement with the use of PCs. The results of this analysis should be interpreted with caution owing to the existence of heterogeneity. Limited evidence suggests an actual reduction in the overall treatment duration. Future studies should be aimed at standardizing the protocol for preparing and administering the PCs. This review did not receive any funding.Trial registration number: PROSPERO CRD42021241221

Biomechanical Analysis of Extraction Space Closure with Various Loop Springs Incorporated into an Archwire

The purpose of this study was to compare the mechanical efficacies of the various loop springs in the extraction space closure. The long-term movement of the teeth was simulated by the finite element method. It was assumed that the tooth moved in the same direction as the initial movement due to elastic deformation of the periodontal ligament. After the spring was activated, the initial movement was calculated, and then the alveolar socket was moved. By repeating this calculation, the teeth moved by accumulating the initial movement. The anterior teeth first tipped lingually and then became upright; thereby, the extraction space was closed for a fixed distance. In all cases, the gable bends were effective in increasing the closing speed. A higher loop increased the closing distance. When the helical loop was replaced with the vertical loop, the closing distance decreased. A spring made of thick wire increased the closing speed but decreased the closing distance. No spring increased both the closing distance and the closing speed at the same time. In clinical settings, an appropriate spring should be selected for each case by giving priority to either the closing distance or speed.

Finite element analysis of the biomechanical effect of clear aligners in extraction space closure under different anchorage controls

Clear aligners (CAs) have attracted increasing attention from patients and orthodontists because of their excellent esthetics and comfort. However, treating tooth extraction patients with CAs is difficult because their biomechanical effects are more complicated than those of traditional appliances. This study aimed to analyze the biomechanical effect of CAs in extraction space closure under different anchorage controls, including moderate, direct strong, and indirect strong anchorage. It could provide several new cognitions for anchorage control with CAs through finite element analysis, further directing clinical practice. A 3-dimensional maxillary model was generated by combining cone-beam computed tomography and intraoral scan data. Three-dimensional modeling software was used to construct a standard first premolar extraction model, temporary anchorage devices, and CAs. Subsequently, finite element analysis was performed to simulate space closure under different anchorage controls. Direct strong anchorage was beneficial for reducing the clockwise occlusal plane rotation, whereas indirect anchorage was conducive for anterior teeth inclination control. In the direct strong anchorage group, an increase in the retraction force would require more specific anterior teeth overcorrection to resist the tipping movement, mainly including lingual root control of the central incisor, followed by distal root control of the canine, lingual root control of the lateral incisor, distal root control of the lateral incisor, and distal root control of the central incisor. However, the retraction force could not eliminate the mesial movement of the posterior teeth, possibly causing a reciprocating motion during treatment. In indirect strong groups, when the button was close to the center of the crown, the second premolar presented less mesial and buccal tipping but more intrusion. The 3 anchorage groups showed significantly different biomechanical effects in both the anterior and posterior teeth. Specific overcorrection or compensation forces should be considered when using different anchorage types. The moderate and indirect strong anchorages have a more stable and single-force system and could be reliable models in investigating the precise control of future tooth extraction patients.

Evaluation and Comparison of Momentto-Force Ratio of a New “PRP Loop” with that of Opus Loop and L LoopA Finite Element Method Study

Introduction: Extraction space closure is the foremost challenging procedure in the field of orthodontics which needs a robust understanding of biomechanics. There are two commonly used methods of space closure, one which involves friction, also called sliding mechanics, and the other is frictionless. The advantages of frictionless mechanics are there is no force loss due to friction and low anchorage taxing. The preferred method for the retraction of teeth is loop mechanics and which ensures controlled tooth movement. Aim: To evaluate and compare the Moment-to-Force (M/F) ratio of PRP loop with that of Opus loop and L loop by Finite Element Method (FEM). Materials and Methods: An in-vitro study was conducted by using FEM analysis in DMIHER University with technical assistance from the Department of Mechanical Engineering VNIT Nagpur. Computer models of Loops design were prepared on Analysis of Systems (ANSYS) version 10 (V10) software. Opus loop, L loop and Platelet-Rich Plasma (PRP) loop were modelled as SOLID 64 beam elements. Different pre-activation bends were given to the models in α and β nodes of the loop. Statistical analysis was done with Statistical Package for Social Sciences (SPSS) version 27.0 software to compare the mean of all three loops. Results: Total 36 FEM models were studied. PRP loop showed greater M/F ratio than Opus and L loop with 15ºα and 25ºβ pre-activation bends in both 0.017×0.025 and 0.019×0.025- inch Titanium Molybdenum Alloy (TMA) wire i.e., 9.09 and 9.12, respectively. On comparison of M/F ratio of PRP loop, Opus loop and L loop prepared with 0.017×0.025 and 0.019×0.025 TMA wire, at 15ºα and 25ºβ pre-activation bend in 0.019×0.025 TMA, PRP loop showed highest M/F ratio of 9.12 as compared to 0.017×0.025 TMA wire. Conclusion: The study concluded that PRP loop is an efficient retraction loop with ideal moment force ratio for translatory movement of tooth. PRP loops had highest M/F ratio than Opus loop and L loop, indicating that PRP can be used for translatory movement of tooth in wires of different materials. Therefore, for proper utilisation of PRP loop, it must be prepared with either 0.017×0.025 inch TMA or 0.019×0.025 inch TMA wire.

Evaluation of maxillary canine and molar movement during the first phase of extraction space closure: a multilevel analysis.

This study was designed to analyze and compare the cusp and apex movements of the maxillary canines and first molars during canine retraction in the first step of extraction space closure, and to evaluate if these teeth follow a curvilinear (acceleration and/or deceleration) movement rate. Twenty-five patients (23.3 ± 5.1 years of age) were enrolled. The retraction of the maxillary canines was accomplished using nickel-titanium closed coil springs (100gf) on 0.020-in stainless steel archwire. Oblique cephalograms were traced and superimposed on the anatomic best fit of the maxilla (before the retraction [T0], and after one month [T1], three [T3], five [T5] and seven [T7] months). Statistics was based in a normally distributed data. Multilevel procedures were used to derive polynomials for each of the measurements. Student's t-test and one-way repeated measures ANOVA were conducted. The level of significance of 5% was adopted. Canine cusps and apexes did not follow a quadratic curve regarding horizontal movement (neither accelerate nor decelerate). Canine and molar cusps showed more horizontal movement than apexes (4.80 mm vs. 2.78 mm, and 2.64 mm vs. 2.17 mm, respectively). Canine did not accelerate or decelerate overtime horizontally; the cusps and apexes of the canines and molars showed more horizontal movement and larger rate at the beginning of canine retraction, followed by significantly smaller and constant movement rate after the first month.

A different method to accelerate orthodontic tooth movement: Randomized controlled trial

Background/Aim: Since both patients and orthodontists want orthodontic treatment to be completed in a short time, various methods have been developed to accelerate orthodontic tooth movement. Vibration applications and interrupted force are noninvasive applications that are easily accepted by the patient. Aim of this study is researching modified interrupted force and vibration together how effect orthodontic tooth movement rate and pain perception that occurs during canine distalization. Material and Methods: Twenty patients (10 males and 10 females) with Class II div 1 malocclusion were selected for this study. The Hycon device on the right side activated by routine protocol, but on the left side activation protocol modified. The patients were randomly divided into 2 groups and one group was applied vibration with AcceleDent device. Each patient was provided with a chart to score the pain they experienced during canine distalization. Results: Fastest tooth movement was measured in the modified protocol(HL)+AcceleDent group (1.44 mm/monthly). The results showed that the orthodontic tooth movement in the groups which AcceleDent device used was faster than the Hycon groups only. Faster movement was observed in the left canines which Hycon device activated by modified protocol compared to right canines. These differences between groups were found statistically significant. Pain over time exhibited similar patterns in all groups. Conclusions: Using modified interrupted force protocol gave more rapid extraction space closure. The application of vibration, as an adjunct to treatment with a fixed orthodontic appliance, significantly increases the rate of orthodontic tooth movement. Vibrational force and modified activation protocol do not have significant effect on pain perception.

Effect of a Submucosal Injection of Platelet-Rich Plasma on the Rate of Orthodontic Tooth Movement - A Split-Mouth, Single-Blind Randomized Controlled Trial.

To investigate the effect of submucosal injection of platelet-rich plasma (PRP) on the rate of mini-implant-supported retraction, using a split-mouth randomized clinical design. Twenty subjects of either gender between 16 and 25 years of age with bimaxillary dentoalveolar protrusion and crowding of <4 mm scheduled to undergo fixed mechanotherapy with the extraction of 1st premolars; were recruited for the study. Those with a periodontally compromised dentition, blood dyscrasias, smoking/alcoholism, or with a history of fixed orthodontic treatment were not considered. The intervention side received a submucosal injection of autologous PRP which was prepared using 10 ml of the patient's blood. The rate of extraction space closure on both sides was recorded and compared monthly for 3 months using a digital caliper. Mean overall retraction was faster on the intervention side as compared to the control side by 1.5 times and was statistically significant with a P value of 0.001. There was no influence of gender on the rate of retraction. There was no reported swelling or discomfort associated with the PRP injection. Submucosal injection of PRP significantly accelerates orthodontic tooth movement and can therefore be used as an effective, safe, and minimally invasive method to expedite orthodontic treatment.

Comparison of retraction efficacy of titanium-molybdenum and titanium-niobium alloy wires – A prospective split-mouth study

Objectives: The study aimed to compare the efficacy of Titanium-Molybdenum (Ti-Mo) and Titanium-Niobium (Ti-Nb) alloy wires as retraction springs, by comparing: The amount and rate of canine retraction, the degree of canine rotation, the change in axial inclination of canines, and the associated anchorage loss. Material and Methods: All 17 participants (age: 18–25 years) to be treated with the first premolar extraction approach by canine retraction were assigned Ti-Mo and Ti-Nb alloy T-loop springs to either of the upper quadrants randomly. Digital intraoral 3-D scans and panoramic radiographs orthopantomagram (OPG) were taken before (T0) and after (T1) the study period (4 months). 3-D superimposition was performed and using the digital models and OPG, changes in canine position, angulation, and anchorage loss were compared between the two groups. Results: There was no significant difference between the two treatment groups for all the parameters pertaining to maxillary canine retraction, that is, canine retraction (P = 0.72), change in axial inclination of canines (P = 0.71), rotation of canines (P = 0.74), and anchorage loss (P = 0.13) as well as extraction space closure (P = 0.74). Conclusion: Ti-Nb and Ti-Mo alloy wires show a similar potency for use in retraction mechanics for orthodontic space closure.

Does the floor of the maxillary sinus affect tooth movement for premolar extraction space closure?

The study investigated orthodontic tooth movement by comparing various horizontal and angular measures of the teeth having different sinus-root relationship (SRR) of patients undergoing first premolar extraction treatment protocols. This retrospective cross-sectional study included 45 Taiwanese adult patients, classified as the control group (n = 15) and the sinus group (n = 30) according to SRR. The control group had type I SRR (sinus floor above the level connecting the buccal and palatal root apices), whereas the sinus group included patients with type V SRR (the buccal and palatal root displayed apical protrusion into the sinus floor). Morphology was identified using pretreatment orthopantomograms. Lateral cephalometric measurements were conducted before treatment (T1) and at debonding (T2). Post debonding, there were no statistically significant difference in the two groups. However, the incisors in the control group became marginally more upright than those of the sinus group, and the molars demonstrated tipping movement with minimal anchorage loss in the sinus group than in the control group. The total treatment time was not significantly different between the 2 groups. The study revealed that the sinus-root relationship does not affect the orthodontic tooth movement. However, a more extensive 3-D study with larger sample size is strongly recommended before coming to any conclusion. The lining of the floor of the maxillary sinus does not affect the orthodontic tooth movement.

Comparison and Measurement of Molar Anchorage Loss during En-Masse Retraction Using Mini-Implant and Conventional Mechanics

Aim: To compare and measure molar anchorage loss during en-masse retraction using mini-implant and conventional mechanics. Objectives: 1) To evaluate the molar anchorage loss during en-masse retraction of anterior teeth by using conventional mechanics. 2) To evaluate the molar anchorage loss during en-masse retraction of anterior teeth by using the orthodontic mini-implant as absolute anchorage. 3) To measure and compare the molar anchorage loss during en-masse retraction using mini-implant and conventional mechanics. Methods: The study was carried out on 10 patients requiring extraction of four first premolars and maximum retraction. On the right side (experimental side) mini-implants were placed between the second premolar and first molar and an e-chain was engaged from the head of the implant to the crimpable hook. On the left side (control side) an e-chain is given from crimpable hook to molar hook for en masse retraction. The retraction space closure was calculated using vernier caliper on the study model after 28weeks of retraction. Lateral cephalogram was taken before and after orthodontic retraction for calculating molar anchor loss. Results: The retraction space closure after 28 weeks showed a mean value of 3.59+0.68mm on the mini-implant side and 3.98+0.62mm on the conventional mechanics side, which was statistically significant. The anchor loss of 0.17+0.3 mm was observed on the mini-implant side and 1.32+0.62 mm was observed in the conventional mechanics after retraction, which was found to be statistically significant. Conclusion: In this study, the molar anchor loss of 0.17+ 0.3mm was seen on the mini-implant side and 1.32+0.6mm on the conventional mechanics side which was significantly more by 1.15mm than the mini-implant side. The closure of extraction space on the mini-implant side was done by retraction of anterior teeth and minimal anchorage loss, while in the conventional mechanics side there was anchor loss of anterior as well as posterior teeth.

Craniofacial Manifestation and Orthosurgical Management of a Patient with Achondroplasia

Achondroplasia is a bone growth disorder results due to failure in endochondral ossification, conversion of cartilages into mature bones. It is the most common metaphyseal dysplastic condition of long bones. The incidence of achondroplasia is 1:25000–30,000 of live births. Our patient was a diagnosed case of achondroplasia, characterized by short stature, disproportionately short arms and legs, and short fingers. Craniofacial features include prominent forehead (frontal bossing), short cranial base, short nose, depressed nasal bridge, short upper lip leading to increased incisal show along with gingival visibility and hyperactive mentalis. Intraoral examination revealed constricted maxillary arch, multiple missing teeth, increased overjet of 12 mm, nonspecific molar, and canine relation bilaterally. Therapeutic intervention included orthosurgical management, i.e., Stage I (presurgical orthodontics)-leveling and alignment followed by closure of extraction spaces; Stage II (surgical management)–le fort-1 osteotomy and maxillary superior repositioning of 6 mm followed by 5 mm bilateral sagittal split ramus osteotomy with anticlockwise rotation of body of the mandible; and Stage III–settling of occlusion and fixed retention in maxillary and mandibular arch. Present case highlights the craniofacial manifestations of achondroplasia its effective management and the potential complications associated. Treating orthodontist should be aware of these features and their consequences in managing the patient to achieve a successful outcome.

Class II extraction treatment with aligners: a reliable approach

Class II extraction approach by means of maxillary first premolars represents a common treatment strategy in order to reduce the overjet and create a stable Class I canine relationship and Class II molar relationship. The objective of this paper is to describe digital planning protocol and complete clinical phases of space closure in Class II malocclusion treatment in adult patient. The accuracy of movements and correction of dental parameters has improved exponentially in recent years, as a result of continuous research performed in aligner orthodontics. However, the most complex movement to realize with aligners is the apical movement, but the application of the G6 protocol for managing extractive cases allows to obtain the final parallelism of the roots with a control of the tipping managed on the digital plan as an overcorrection (overtipping) of the roots adjacent to the extraction site. Through the description of two cases, this article will present the application of the specific protocol for first premolars extraction in order to manage anchorage and closure of extraction spaces. All patients finished with proper OVJ and OVB with a Class II molar relationship and Class I canine relationship respecting face balance and smile arc. The Invisalign G6 protocol through the use of SmartStage™ technology combined with SmartForce™ features provides vertical control during anterior sector retraction and teeth body movement maintaining maximum posterior anchorage.