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

2017 ◽  
Vol 22 (5) ◽  
pp. 47-55 ◽  
Author(s):  
A. Sumathi Felicita
Keyword(s):  
Clinical Outcomes ◽  
Anterior Segment ◽  
Applied Force ◽  
Occlusal Plane ◽  
Conceptual Approach ◽  
Mini Implants ◽  
Anterior Teeth ◽  
Clinical Scenarios ◽  
Retraction Force ◽  
En Masse Retraction

ABSTRACT Objective: 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.

scholarly journals Dual-section versus conventional archwire for en-masse retraction of anterior teeth with direct skeletal anchorage: a finite element analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ryo Hamanaka ◽  
Daniele Cantarella ◽  
Luca Lombardo ◽  
Lorena Karanxha ◽  
Massimo Del Fabbro ◽  
...  
Keyword(s):  
Finite Element ◽  
Tooth Movement ◽  
Occlusal Plane ◽  
Skeletal Anchorage ◽  
Element Analysis ◽  
Posterior Teeth ◽  
Posterior Portion ◽  
Anterior Teeth ◽  
Retraction Force ◽  
En Masse Retraction

Abstract Background The aim of this study is to compare the biomechanical effects of the conventional 0.019 × 0.025-in stainless steel archwire with the dual-section archwire when en-masse retraction is performed with sliding mechanics and skeletal anchorage. Methods Models of maxillary dentition equipped with the 0.019 × 0.025-in archwire and the dual-section archwire, whose anterior portion is 0.021 × 0.025-in and posterior portion is 0.018 × 0.025-in were constructed. Then, long-term tooth movement during en-masse retraction was simulated using the finite element method. Power arms of 8, 10, 12 and 14 mm length were employed to control anterior torque, and retraction forces of 2 N were applied with a direct skeletal anchorage. Results For achieving bodily movement of the incisors, power arms longer than 14 mm were required for the 0.019 × 0.025-in archwire, while between 8 and 10 mm for the dual-section archwire. The longer the power arms, the greater the counter-clockwise rotation of the occlusal plane was produced. Frictional resistance generated between the archwire and brackets and tubes on the posterior teeth was smaller than 5% of the retraction force of 2 N. Conclusions The use of dual-section archwire might bring some biomechanical advantages as it allows to apply retraction force at a considerable lower height, and with a reduced occlusal plane rotation, compared to the conventional archwire. Clinical studies are needed to confirm the present results.

scholarly journals Initial forces experienced by the anterior and posterior teeth during dental-anchored or skeletal-anchored en masse retraction in vitro

2016 ◽  
Vol 87 (4) ◽  
pp. 549-555 ◽  
Author(s):  
David Lee ◽  
Giseon Heo ◽  
Tarek El-Bialy ◽  
Jason P. Carey ◽  
Paul W. Major ◽  
...  
Keyword(s):  
Anterior Segment ◽  
Nickel Titanium ◽  
Skeletal Anchorage ◽  
Posterior Teeth ◽  
Treatment Groups ◽  
Anterior Teeth ◽  
Retraction Force ◽  
En Masse Retraction ◽  
Maxillary Arch

ABSTRACT Objective: To investigate initial forces acting on teeth around the arch during en masse retraction using an in vitro Orthodontic SIMulator (OSIM). Materials and Methods: The OSIM was used to represent the full maxillary arch in a case wherein both first premolars had been extracted. Dental and skeletal anchorage to a posted archwire and skeletal anchorage to a 10-mm power arm were all simulated. A 0.019 × 0.025-inch stainless steel archwire was used in all cases, and 15-mm light nickel-titanium springs were activated to approximately 150 g on both sides of the arch. A sample size of n = 40 springs were tested for each of the three groups. Multivariate analysis of variance (α = 0.05) was used to determine differences between treatment groups. Results: In the anterior segment, it was found that skeletal anchorage with power arms generated the largest retraction force (P < .001). The largest vertical forces on the unit were generated using skeletal anchorage, followed by skeletal anchorage with power arms, and finally dental anchorage. Power arms were found to generate larger intrusive forces on the lateral incisors and extrusive forces on the canines than on other groups. For the posterior anchorage unit, dental anchorage generated the largest protraction and palatal forces. Negligible forces were measured for both skeletal anchorage groups. Vertical forces on the posterior unit were minimal in all cases (<0.1 N). Conclusions: All retraction methods produced sufficient forces to retract the anterior teeth during en masse retraction. Skeletal anchorage reduced forces on the posterior teeth but introduced greater vertical forces on the anterior teeth.

scholarly journals Finite element study of controlling factors of anterior intrusion and torque during Temporary Skeletal Anchorage Device (TSAD) dependent en masse retraction without posterior appliances: Biocreative hybrid retractor (CH-retractor)

2019 ◽  
Vol 90 (2) ◽  
pp. 255-262 ◽  
Author(s):  
Sung-Seo Mo ◽  
Min-Ki Noh ◽  
Seong-Hun Kim ◽  
Kyu-Rhim Chung ◽  
Gerald Nelson
Keyword(s):  
Finite Element ◽  
Anterior Segment ◽  
Two Dimensions ◽  
Element Analysis ◽  
Bodily Movement ◽  
Anterior Teeth ◽  
Temporary Skeletal Anchorage ◽  
Anterior Segments ◽  
Sophisticated Analysis ◽  
En Masse Retraction

ABSTRACT Objectives: To evaluate, using the finite element method (FEM), the factors that allow control of the anterior teeth during en masse retraction with the Biocreative hybrid retractor (CH-retractor) using different sizes of nickel-titanium (NiTi) archwires and various gable bends on the stainless-steel (SS) archwires. Materials and Methods: Using FEM, the anterior archwire section, engaged on the anterior dentition, was modeled in NiTi, and another assembly, the posterior guiding archwire, was modeled in SS. Two dimensions (0.016 × 0.022- and 0.017 × 0.025-inch NiTi) of the anterior archwires and different degrees (0°, 15°, 30°, 45°, and 60°) of the gable bends on the guiding wire were applied to the CH-retractor on the anterior segment to evaluate torque and intrusion with 100-g retraction force to TSADs. Finite element analysis permitted sophisticated analysis of anterior tooth displacement. Results: With a 0° gable bend all anterior teeth experienced extrusion. The canines showed a larger amount of extrusion than did the central and lateral incisors. With a gable bend of >15°, all anterior teeth exhibited intrusion. Bodily movement of the central incisor required a 30°∼45° gable bend when using anterior segments of 0.016 × 0.022-inch NiTi and 15°∼30° gable bend with the 0.017 × 0.025-inch NiTi. Conclusions: With the CH-retractor, varying the size of the NiTi archwire and/or varying the amount of gable bend on the SS archwire affects control of the anterior teeth during en masse retraction without a posterior appliance.

scholarly journals Optimal Loading Conditions for Controlled Movement of Anterior Teeth in Sliding Mechanics

2009 ◽  
Vol 79 (6) ◽  
pp. 1102-1107 ◽  
Author(s):  
Jun-ya Tominaga ◽  
Motohiro Tanaka ◽  
Yoshiyuki Koga ◽  
Carmen Gonzales ◽  
Masaru Kobayashi ◽  
...  
Keyword(s):  
Tooth Movement ◽  
Anterior Segment ◽  
Orthodontic Tooth Movement ◽  
Loading Conditions ◽  
Maxillary Central Incisor ◽  
Bodily Movement ◽  
Anterior Teeth ◽  
Optimal Loading ◽  
Sliding Mechanics ◽  
Retraction Force

Abstract Objective: To determine optimal loading conditions such as height of retraction force on the power arm and its position on the archwire in sliding mechanics. Materials and Methods: A 3D finite element method (FEM) was used to simulate en masse anterior teeth retraction in sliding mechanics. The degree of labiolingual tipping of the maxillary central incisor was calculated when the retraction force was applied to different heights of a power arm set mesial or distal to the canine. Results: When the power arm was placed mesial to the canine, at the level of 0 mm (bracket slot level), uncontrolled lingual crown tipping of the incisor was observed and the anterior segment of the archwire was deformed downward. At a power arm height of 5.5 mm, bodily movement was produced and the archwire was less deformed. When the power arm height exceeded 5.5 mm, the anterior segment of the archwire was raised upward and lingual root tipping occurred. When the power arm was placed distal to the canine, lingual crown tipping was observed up to a level of 11.2 mm. Conclusions: Placement of the power arm of an archwire between the lateral incisor and canine enables orthodontists to maintain better control of the anterior teeth in sliding mechanics. Both the biomechanical principles associated with the tooth's center of resistance and the deformation of the archwire should be taken into consideration for predicting and planning orthodontic tooth movement.

OPTIMUM FORCE SYSTEM FOR EN-MASSE RETRACTION OF SIX MAXILLARY ANTERIOR TEETH IN LABIAL ORTHODONTICS

2020 ◽  
Vol 20 (02) ◽  
pp. 1950066
Author(s):  
ABHISHEK M. THOTE ◽  
RASHMI V. UDDANWADIKER ◽  
KRISHNA SHARMA ◽  
SUNITA SHRIVASTAVA ◽  
VENKATESWAR REDDY
Keyword(s):  
Theoretical Model ◽  
Research Study ◽  
Sagittal Plane ◽  
Optimum Combination ◽  
Force System ◽  
Anterior Teeth ◽  
Slot Size ◽  
Retraction Force ◽  
En Masse Retraction

The orthodontists generally do not recommend application of force system above the archwire level owing to additional attachments and patient’s discomfort. Hence, the present research study focusses on application of retraction force system at the archwire level. The objective of this study is to specify an optimum combination of archwire and bracket slot size for en-masse (simultaneous) parallel retraction of six maxillary anterior teeth in labial orthodontics (LaO). In this research study, the concept (theoretical) model has been developed based on simple principles of mechanics to estimate the torque generated by different sizes of archwire in bracket slots. Based on torque value, retraction force developed by each combination of archwire and slot size was determined and compared with required retraction force of 150 gram-force on each side of sagittal plane. For combination of [Formula: see text] inch stalinless steel SS archwire and 0.022 inch SS bracket slot, magnitude of computed retraction force matched closely with aforementioned required force than other combinations and hence, it is recommended in the present research study. The validation of selected combination of archwire and bracket slot size was done successfully by in vivo (clinical) experimentation on three patients. Thus, it proves that the aforementioned combination of archwire and bracket slot size is more suitable than others for retraction force system applied at archwire level.

Review of maxillary molar distalising appliances with palatal anchorage on miniimplants

2018 ◽  
Vol 14 (4) ◽  
pp. 296-308
Author(s):  
Małgorzata Sanecka ◽  
Katarzyna Becker ◽  
Anna Greń ◽  
Mariusz Świerk
Keyword(s):  
Literature Review ◽  
Hard Palate ◽  
Anterior Segment ◽  
Dental Arch ◽  
Mini Implants ◽  
Anterior Teeth ◽  
Pubmed Database ◽  
Maxillary Molar ◽  
Distal Jet ◽  
Being Moved

Maxillary molar distalisation is one of treatment methods for patients with Angle class II. Intraoral appliances supported by patient’s own teeth inevitably lead to loss of anchorage. Mini-implants are additionally used to reduce this side effect. The area of the hard palate is the best anatomical place to attach mini-implants, and it provides the lowest risk of complications. <b>Aim.</b> To present issues associated with appliances used for maxillary molar distalisation that are based on bone anchorage in the hard palate region. <b>Material and methods.</b> The literature review using the PubMed database and the Polish Medical Bibliography with the following key words: molar distalisation, orthodontic miniimplants, skeletal anchorage. 37 positions from the years 1996–2018 were selected and analysed. <b>Results.</b> As a result of the literature review, 37 articles describing nine distalisation appliances modelled on three basic constructions: Pendulum, Distal Jet and Keles Slider, and the MCPP appliance were identified. <b>Summary.</b> Distalising appliances supported by palatal mini-implants do not lead to loss of anchorage in the anterior segment. At the stage of anterior teeth retraction they can be used for stabilisation of the distalised segment. They are less visible compared to extraoral appliances or those placed on the external side of the dental arch. They can be used simultaneously with fixed braces or during preparation for subsequent therapy with fixed braces. Depending on the design, they are not free of the side effects typical of the prototypes they originate from, i.e. rotation and inclination of molars. The most parallel distal movement of teeth is made possible by appliances whose force acts at the height of the CR (centre of resistance) of teeth being moved.

Management of trauma to the anterior segment of the maxilla: alveolar fracture and primary incisors crown and root fracture

2021 ◽  
Vol 33 (2) ◽  
pp. 16-20
Author(s):  
Muna S Khalaf ◽  
Bayan S Khalaf ◽  
Shorouq M Abass
Keyword(s):  
Soft Tissue ◽  
Primary Teeth ◽  
Alveolar Bone ◽  
Anterior Segment ◽  
Dental Trauma ◽  
Permanent Tooth ◽  
Permanent Teeth ◽  
Normal Position ◽  
Anterior Teeth ◽  
The Impact

Background: An injury to both the primary and permanent teeth and the supporting structures is one of the most common dental problems seen in children. Splinting is usually difficult or impossible to perform in the primary dentition (due to diminutive room size and lack of patient cooperation). Healing must, therefore, occur despite mobility at the fracture line, usually resulting in interposition of connective tissue. In some instances, infection will occur in the coronal pulp. The present study reported a case of trauma to the anterior primary teeth and alveolar bone in a four year old child. The trauma has caused fracture to the crowns and roots of the primary anterior teeth. The following case was managed in a procedure that may provide primary teeth subjected to trauma a better chance than extraction with a better prognosis. Case presentation: a 4 and a half year old child was subjected to trauma in anterior segment of maxilla. Suturing of the torn soft tissue was the first step followed by pulpotomy for the left primary lateral incisor. Fixation of the right primary central and lateral incisors was done by acid etch wire fixation. Both clinical and radiographic follow up was carried out for 6.4 years. Results: healing of the soft tissue was observed after one week and completed after two months. Fixation of the teeth continued for ten months. The fracture lines in the roots remained in position. Clinically there was no sign of any pulpal inflammation or necrosis. Radiographically, no signs of infection to the surrounding tissues could be seen, no resorption in the alveolar bone, external or internal resorption of the root did not happen also. After ten months fixation ended and the wire was removed. At that time there was normal resorption of the roots of the primary incisors in relation with the normal development of the permanent incisors. After 3 years both permanent central incisors erupted in their normal position. After 6.4 years all four permanent incisors erupted into occlusion in their normal position. Conclusion: primary teeth with root fractures and severely mobile coronal fragments can be treated by a conservative approach. The severity of the sequels is directly related to the degree of permanent tooth formation (child’s age), type of dental trauma and extent of the impact. Key words: trauma, primary incisors, fractured crown and root

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