Retraction Of Maxillary Anterior Teeth Research Articles

Effectiveness of anchorage with temporary anchorage devices during anterior maxillary tooth retraction: A randomized clinical trial.

ObjectiveThis study evaluated the efficiency of anchorage provided by temporary anchorage devices (TADs) in maxillary bicuspid extraction cases during retraction of the anterior teeth using a fixed appliance.MethodsPatients aged 12 to 50 years with malocclusion for which bilateral first or second maxillary bicuspid extractions were indicated were included in the study and randomly allocated to the TAD or control groups. Retraction of the anterior teeth was achieved using skeletal anchorage in the TAD group and conventional dental anchorage in the control group. A computed tomography (CT) scan was performed after alignment of teeth, and a second CT scan was performed at the end of extraction space closure in both groups. A three-dimensional superimposition was performed to visualize and quantify the maxillary first molar movement during the retraction phase, which was the primary outcome, and the stability of TAD movement, which served as the secondary outcome.ResultsThirty-four patients (17 in each group) underwent the final analysis. The two groups showed a significant difference in the movement of the first maxillary molars, with less significant anchorage loss in the TAD group than that in the control group. In addition, TAD movement showed only a slight mesial movement on the labial side. On the palatal side, the mesial TAD movement was greater.ConclusionsIn comparison with conventional dental anchorage, TADs can be considered an efficient source of anchorage during retraction of maxillary anterior teeth. TADs remain stable when correctly placed in the bone during the anterior tooth retraction phase.

Comparison of stress distribution on bone and mini-implants during en-masse retraction of maxillary anterior teeth in labial and lingual orthodontics: A three-dimensional finite element analysis

INTRODUCTION: In fixed orthodontic treatment, space closure is one of the most challenging aspects. The common method of en-masse retraction in sliding mechanics is the use of the elastomeric chain and power arm. Recently, titanium mini-implants are used as absolute sources of orthodontic anchorage. Lingual and labial bracket placement influences the pattern of tooth movement, but the stress that occurs around the teeth, the mini-implants, and the surrounding bone can be accurately mapped using a three-dimensional (3D) finite element method. AIM: The aim of this study was to evaluate the stress distribution on bone and mini-implants during en-masse retraction of maxillary anterior teeth in labial and lingual orthodontics with the help of finite element analysis. MATERIALS AND METHODS: Following the standard protocol for 3D finite element models, two models were created for en-masse retraction of the six anterior teeth: one model using the labial technique with the mini-implant placed at a height of 5 mm from the alveolar crest bucally and the second model using the lingual technique with the mini-implant placed at a height of 5 mm from the gingival margin palatally, and 200 g of retraction forces was given using a elastomeric chain. RESULTS AND CONCLUSIONS: The Von Mises stresses in the bone and mini-implant were significantly higher in the lingual technique as compared to the labial technique. The variations in stress patterns in the bone and the mini-implant in the labial and lingual technique could be the result of difference in the inter-bracket distance, point of force application, and its location to the center of resistance of the dentition.

Quantification of intrusive/retraction force and moment generated during en-masse retraction of maxillary anterior teeth using mini-implants: A conceptual approach.

ABSTRACTObjective: The aim of the present study was to clarify the biomechanics of en-masse retraction of the upper anterior teeth and attempt to quantify the different forces and moments generated using mini-implants and to calculate the amount of applied force optimal for en-masse intrusion and retraction using mini-implants. Methods: The optimum force required for en-masse intrusion and retraction can be calculated by using simple mathematical formulae. Depending on the position of the mini-implant and the relationship of the attachment to the center of resistance of the anterior segment, different clinical outcomes are encountered. Using certain mathematical formulae, accurate measurements of the magnitude of force and moment generated on the teeth can be calculated for each clinical outcome. Results: Optimum force for en-masse intrusion and retraction of maxillary anterior teeth is 212 grams per side. Force applied at an angle of 5o to 16o from the occlusal plane produce intrusive and retraction force components that are within the physiologic limit. Conclusion: Different clinical outcomes are encountered depending on the position of the mini-implant and the length of the attachment. It is possible to calculate the forces and moments generated for any given magnitude of applied force. The orthodontist can apply the basic biomechanical principles mentioned in this study to calculate the forces and moments for different hypothetical clinical scenarios.

A comparative evaluation of different compensating curves and power arm length during retraction of maxillary anterior teeth: A finite element study

Introduction: The strategic design of an appliance for anterior retraction by using orthodontic mini-implant anchorage and sliding mechanics must take into account the height of the power arm and compensating curve in archwire. This study was conducted to analyze the change in maxillary anterior teeth displacement and stress distribution using different compensating curves in the arch wire and varying power arm length in first premolar extraction case during sliding mechanics. Materials and Methods: 6 geometric models were created using ANSYS software. This geometric model was converted into a finite element model with the help of software HYPERMESH 11.0. Bilaterally mini-implants were placed in the bone between the roots of maxillary second premolar and first molar. Power arms were placed at two heights – 3 mm and 5.5mm. Compensatory curves were placed in the archwire (0, 3mm or 5mm) and a force of 150 gms was applied using NiTi coil springs bilaterally. Stresses in bone and tooth displacements were analyzed. Results: There was more bodily movement of the teeth using the longer power arms. Incorporating a compensatory curve further helped to reduce tipping. The tooth that showed most bodily movement was the lateral incisor followed by central incisor and least by the canine. There was increased intrusion of the incisors and extrusion of canine with increase in power arm height. Conclusion: Increase in power arm height causes an increased intrusive tendency and increased bodily movement during en masse retraction of anterior teeth using mini- implant anchorage. Incorporation of a 5mm compensatory curve further helps reduce the tipping tendency of the anterior teeth.

EVALUATION OF MINI-IMPLANT ANCHORAGE SYSTEM FOR EN-MASSE RETRACTION OF MAXILLARY ANTERIOR TEETH VERSUS CONVENTIONAL METHOD

Objectives: The purpose of this study was to compare the skeletodental and soft tissue changes and the duration needed for closure of extraction space after en-masse retraction of maxillary anterior teeth using mini-implant anchorage system in the treatment of maxillary dentoalveolar protrusion cases compared with two step retraction with conventional method of anchorage reinforcement. Materials and Methods: The study sample consisted of twenty adult orthodontic patients (3 males and 17 females) with maxillary dentoalveolar protrusion and required first premolar extraction and maximum anchorage. They were randomly divided into two treatment groups (10 subjects in each group). Group 1, anterior space closure with en-masse retraction aided by mini- implant anchorage system, or group 2, anterior space closure with two-step retraction technique aided by conventional method of anchorage. Lateral cephalometric head films were taken just before retraction of maxillary anterior teeth and immediately after closure of the extraction space for the evaluation of the treatment changes. Statistical analyses of the data were performed at a significance level of P <0.05. Results: For the skeletal parameters, a statistically significant decrease in the facial vertical dimensions was seen in G1, but the variables in G2 showed no significant differences (P > 0.05). Anchorage loss, in both the horizontal and vertical directions, was noted in G2, whereas G1 showed anchorage gain and intrusion of molars. Group 1 had greater anterior tooth retraction (7.8 mm in 9.6 months) than did the conventional anchorage group (5.5 mm in 12.4 months). However, no significant differences in the mean retraction time were noted between the 2 groups. Upper incisors were intruded in G 1 (2.3 mm) and extruded (1.1 mm) in G 2. The soft-tissue response was greater changes in G1 with significant differences were found in the nasolabial angle and amount of upper lip retraction between the groups (P < 0.05). Conclusion: Mini-implants provided absolute anchorage to allow greater skeletal, dental, and esthetic changes in patients requiring maximum anterior retraction, when compared with other conventional methods of anchorage reinforcement. However no differences in the mean retraction time were noted between the 2 groups.

Torque Loss in En-Masse Retraction of Maxillary Anterior Teeth Using Miniimplants with Force Vectors at Different Levels: 3D FEM Study.

This FEM study was conducted to quantify the amount of torque loss in maxillary anterior teeth by applying force vectors from different levels to the anterior retraction hook at various heights and comparing with that of molar anchorage system. Five 3D FEM models were constructed with force vectors at different levels: HOT-High Orthodontic Traction (13.5mm from archwire) to ARH1- Anterior Retraction Hook (5mm), HOT to ARH2 (8mm), LOT- Low Orthodontic Traction (8 mm) to ARH1, LOT to ARH2 and from conventional molar hook to ARH1. Mini-implants were placed buccally between the roots of second premolar and first molar. Torque loss was calculated by measuring the displacement of the teeth at crown tip and root apex in two planes i.e. sagittal and vertical using Y and Z axis respectively in all the five models. The results were statistically analyzed by using Kruskal Wallis ANOVA and Mann-Whitney U-test. HOT to ARH1 showed that the anterior teeth moved bodily (p =0.5127), followed by molar hook - ARH1(p=0.0495*) which showed mild uncontrolled tipping. Whereas the HOT- ARH2, LOT - ARH1,and LOT - ARH2 models exhibited uncontrolled tipping with maximum torque loss in LOT - ARH1 (p=0.0001*). It can be concluded that bodily movement with very minimal torque loss was observed in HOT-ARH1 model whereas the maximum torque loss was recorded in LOT-ARH2 model. Conventional molar anchorage group showed uncontrolled tipping with some amount of extrusion and anchor loss of posteriors.

Camouflage of Class II Division I malocclusion with retrusion utility arch: A case report

Introduction: There are diff erent treatment modalities for correction of Class II malocclusion. The camoufl age treatment is a method of extraction of premolars to correct borderline skeletal malocclusion. Utility arches have diff erent roles in various stages of orthodontic treatment. The retrusion utility arch is a useful method in camoufl age treatment to obtain intrusion and retrusion of the upper anterior teeth. Aim: The case report documented the treatment of 14-year-old boy with borderline skeletal Class II malocclusion with over jet of 7 mm, 100% deep bite and angle Class II molar, canine, and incisor relationships. Methods: The orthodontic treatment was initiated using 0.022″ Pre-adjusted edge-wise appliances (PEA) with extraction of 14 and 24 with maximum anchorage. After the initial leveling and alignment, intrusion and retraction of maxillary anterior teeth were done using 0.016″ × 0.022″ titanium molybdenum alloy retrusion utility arch. Elastic module tie back was used for upper canine retraction. Finishing and detailing was done after the space closure. Results: The treatment objective of normal over jet and overbite, correction of crowding and achieving Class I canine and incisor relationship were achieved. Conclusion: A stable, harmonious occlusion was achieved after 24 months of PEA treatment along with retrusion utility arch. An upper wrapped around retainer, and lower lingual bonded retainer were issued to retain the stable occlusion.

Rapid Maxillary Anterior Teeth Retraction En Masse by Bone Compression: A Canine Model

ObjectiveThe present study sought to establish an animal model to study the feasibility and safety of rapid retraction of maxillary anterior teeth en masse aided by alveolar surgery in order to reduce orthodontic treatment time.MethodExtraction of the maxillary canine and alveolar surgery were performed on twelve adult beagle dogs. After that, the custom-made tooth-borne distraction devices were placed on beagles' teeth. Nine of the dogs were applied compression at 0.5 mm/d for 12 days continuously. The other three received no force as the control group. The animals were killed in 1, 14, and 28 days after the end of the application of compression.ResultsThe tissue responses were assessed by craniometric measurement as well as histological examination. Gross alterations were evident in the experimental group, characterized by anterior teeth crossbite. The average total movements of incisors within 12 days were 4.63±0.10 mm and the average anchorage losses were 1.25±0.12 mm. Considerable root resorption extending into the dentine could be observed 1 and 14 days after the compression. But after consolidation of 28 days, there were regenerated cementum on the dentine. There was no apparent change in the control group. No obvious tooth loosening, gingival necrosis, pulp degeneration, or other adverse complications appeared in any of the dogs.ConclusionsThis is the first experimental study for testing the technique of rapid anterior teeth retraction en masse aided by modified alveolar surgery. Despite a preliminary animal model study, the current findings pave the way for the potential clinical application that can accelerate orthodontic tooth movement without many adverse complications.Clinical RelevanceIt may become a novel method to shorten the clinical orthodontic treatment time in the future.

Residents’ journal review

Residents’ journal review

A comparitive clinical study between self tapping and drill free screws as a source of rigid orthodontic anchorage.

Self-tapping miniscrews are commonly being used as a temporary anchorage device for orthodontic purpose. A prerequisite for the insertion of these screws is the preparation of a pilot hole, which is time consuming and may result in damage to nerves, tooth root, drill bit breakage and thermal necrosis of bone. On the other hand the design of drill-free screws enables them to be inserted without drilling. The aim of this prospective study was to compare the stability and clinical response of the soft tissue around the self tapping and drill free screws when used for orthodontic anchorage for en mass retraction of maxillary anterior teeth. The study sample consisted of 20 patients requiring retraction of maxillary anterior teeth. The screws were placed in the alveolar bone between maxillary 2nd premolar and 1st molar bilaterally at the junction of attached gingiva and moveable mucosa. Pilot hole was drilled on the side which was selected for insertion of the self tapping screw under copious irrigation, after which it was inserted. Drill free screw was inserted on the contralateral side without predrilling. All screws were immediately loaded with 150-200gm of retraction force. Patients were recalled for regular follow up for a period of 6months. If the screws became mobile or showed any signs of inflammation during the course of the study, they were considered to be a failure. After a period of 6months an overall success rate of 77.5% was noted. Four self tapping and five drill-free screws failed during the study. There was no statistically significant difference between the two types of screws with respect to success/failure. Mobility was found to be the major cause for the failure. Both self-tapping and the drill-free screws are effective anchorage units. But the latter have an edge over the conventional self-tapping screws because of decrease in operative time, little bone debris, less thermal damage, lower morbidity, and minimal patient discomfort as predrilling is not required, thus they can be used as a viable alternative. But self-tapping screws are still recommended for areas with high bone density and thick cortical bone.

Dentoskeletal and Soft Tissue Effects of Mini-Implants in Class II division 1 Patients

To examine the skeletal, dental, and soft tissue treatment effects of retraction of maxillary anterior teeth with mini-implant anchorage in nongrowing Class II division 1 female patients. Twenty-three patients (overjet > or =7 mm) were selected on the basis of predefined selection criteria. Treatment mechanics consisted of retraction of anterior teeth by placing mini-implants in the interdental bone between the roots of the maxillary first molar and second premolar. A force of 150 g was applied, bilaterally. Treatment effects were analyzed by taking lateral cephalograms and study casts at T1 (before initiation of retraction) and at T2 (after complete space closure). The upper anterior teeth showed significant retraction (5.18 +/- 2.74 mm) and intrusion (1.32 +/- 1.08 mm). The upper first molar also showed some distal movement and intrusion, but this was not significant (P > .05). The upper and lower lips were retracted by 2.41 mm and 2.73 mm, respectively, and the convexity angle reduced by over 2 degrees (P < .001). Mini-implants provided absolute anchorage to bring about significant dental and soft tissue changes in moderate to severe Class II division 1 patients and can be considered as possible alternatives to orthognathic surgery in select cases.

En Masse Retraction and Two-Step Retraction of Maxillary Anterior Teeth in Adult Class I Women

To compare the amount of anchorage loss of the maxillary posterior teeth and amount of retraction of the maxillary anterior teeth between en masse retraction and two-step retraction of the anterior teeth. The sample consisted of 30 female adult patients with Class I malocclusion and lip protrusion who needed maximum posterior anchorage. The sample was subdivided into group 1 (n = 15, mean age = 21.4 years, en masse retraction) and group 2 (n = 15, mean age = 24.6 years, two-step retraction). Lateral cephalograms were taken before (T1) and after treatment (T2). Nine skeletal and 10 anchorage variables were measured, and independent t-test was used for statistical analysis. Although the amount of horizontal retraction of the maxillary anterior teeth was not different between the two groups, there was mild labial movement of the root apices of the upper incisors in group 2 at T2. There were no significant differences in the degree of anchorage loss of the maxillary posterior teeth between the two groups. Bodily and mesial movements of the upper molars occurred in both groups. Approximately 4 mm of the retraction of the upper incisal edges resulted from 1 mm of anchorage loss in the upper molars in both groups. No significant differences existed in the degree of anchorage loss of the upper posterior teeth and the amount of retraction of the upper anterior teeth associated with en masse retraction and two-step retraction of the anterior teeth.

“En Masse” retraction of maxillary anterior teeth with anterior headgear

In the treatment of the first premolar extraction cases with certain techniques, incisor retraction is realized after canine distalization. In maximum anchorage cases, retraction of anterior segments require more posterior anchorage. This treatment concept is still valid, however, the difficult anchorage control is considered a major drawback. The purpose of this study is to introduce our technique for the “en masse” retraction of maxillary anterior teeth after first premolar extraction and discuss its effects. The technique consists of the application of extraoral traction on canines, followed by banding of maxillary anterior teeth, to form them as a mass. Advantages of our mechanics are as follows: (1) Anterior headgear may have the advantage of retracting anterior teeth with minimum strain on posterior anchorage. (2) The adjustability of the outer bow in relation to the premaxilla's center of resistance, provides effective desired movements. (3) Intrusion and torque control are achieved in the course of anterior segment retraction. (Am J Orthod Dentofac Orthop 1997;112:473-9.)

Nasal imbalance and the orthodontic patient

U nquestionably, some of the most difficult and disappointing problems the orthodontist treats are those in which nasal development produces a distortion of the face. Such development may be a major deterrent in achieving satisfactory facial harmony. This is especially true in the growing patient whose malocclusion necessitates retraction of anterior teeth. The lip flattening incident to tooth movement and the excessive nasal growth occurring concomitantly may produce a severely distorted profile. This can be a source of great concern to the patient and his parents. Such imbalance can also be a source of additional work, worry, and concern to the orthodontist throughout the entire treatment period. He may plan his therapy to avoid excessive retraction of teeth, use reverse-pull cxtra.oral devices, design numerous anchorage-slipping appliances, and even treat frank extraction cases on a noncxtraction basis. All manner of mechanical systems are employed in a desperate attempt to prevent excessive flattening of the face. Unfortunately, nasal growth usually continues inexorably to its final dimension and form, regardless of the orthodontist’s conjuring. In many ca.ses the simple retraction of maxillary anterior teeth produces a face which may be less attractive than it was before treatment. Rhinoplastic surgery during or after orthodontic treatment can contribute dramatically to the establishment of facial harmony, one of the paramount objectives of orthodontic treatment. This study represents an atbempt to evaluate the interrelationship between abnormal nasal development, orthodontic mechanotherapy, and elective rhinoplastic surgery in achieving that esthetic goal : facial balance.

Nasal imbalance and the orthodontic patient

U nquestionably, some of the most difficult and disappointing problems the orthodontist treats are those in which nasal development produces a distortion of the face. Such development may be a major deterrent in achieving satisfactory facial harmony. This is especially true in the growing patient whose malocclusion necessitates retraction of anterior teeth. The lip flattening incident to tooth movement and the excessive nasal growth occurring concomitantly may produce a severely distorted profile. This can be a source of great concern to the patient and his parents. Such imbalance can also be a source of additional work, worry, and concern to the orthodontist throughout the entire treatment period. He may plan his therapy to avoid excessive retraction of teeth, use reverse-pull cxtra.oral devices, design numerous anchorage-slipping appliances, and even treat frank extraction cases on a noncxtraction basis. All manner of mechanical systems are employed in a desperate attempt to prevent excessive flattening of the face. Unfortunately, nasal growth usually continues inexorably to its final dimension and form, regardless of the orthodontist’s conjuring. In many ca.ses the simple retraction of maxillary anterior teeth produces a face which may be less attractive than it was before treatment. Rhinoplastic surgery during or after orthodontic treatment can contribute dramatically to the establishment of facial harmony, one of the paramount objectives of orthodontic treatment. This study represents an atbempt to evaluate the interrelationship between abnormal nasal development, orthodontic mechanotherapy, and elective rhinoplastic surgery in achieving that esthetic goal : facial balance.