Evaluation of the Anchorage Loss During En-masse Retraction in Orthodontic Patients With Maxillary Protrusion

Study Overview
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Brief Summary
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There is scarcity in literature regarding the effectiveness of friction and frictionless mechanics during ''En-masse retraction''technique on anchorage loss of posterior segment in orthodontic patients with maxillary protrusion. Moreover there is deficiency in studies measuring the patient pain and satisfaction regarding the different techniques of retraction. The aim of the current study is to evaluate the effects of friction versus frictionless mechanics, implemented during En-masse retraction, on anchorage loss. Additionally, assessment of both techniques regarding their rates, effects on root resorption as well as patient satisfaction.

Detailed Description
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One of the most common complaints of orthodontic patients is proclination of anterior teeth where there is an increase in facial convexity and as well as incompetent lips. Bimaxillary dentoalveolar protrusion and class II division I cases always have this appearance. Frequently this situation requires extraction of the first premolars followed by fixed orthodontic appliance for space closure and retraction of anterior teeth. Different techniques are used including Two-step retraction where canines are retracted as a first step followed by anterior four incisors as a second step and En-masse retraction where anterior teeth are retracted as one unit. However, the method of En-masse retraction is controversial - whether to use frictionless or friction mechanics.

Official Title
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Evaluation of the Anchorage Loss During En-masse Retraction in Orthodontic Patients With Maxillary Protrusion Using Friction Versus Frictionless Mechanics: A Randomized Clinical Trial

Conditions
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Bimaxillary Protrusion

Intervention / Treatment
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* Procedure: Power chain and Crimpable hook fro En-masse Retraction
* Procedure: T-loop


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Orthodontic patients (both genders) Age range (14-24) Patients requiring 1st premolars extraction followed by ''En-masse retraction'' (Bimaxillary Protrusion or Class II division 1 cases). Patients with fully erupted permanent teeth (not necessarily including the 3rd molar). Cases requiring maximum anchorage during anterior segment retraction. Cases with minimal crowding (2-3) mm Exclusion Criteria: Patients suffering from any systemic diseases interfering with tooth movement. Patients with extracted or missing permanent teeth. (except for third molars). Patients with badly decayed teeth. Patients with any parafunctional habits (i.e. Bruxism, tongue thrusting, mouth breathing, etc....). Patients with previous orthodontic treatment

Ages Eligible for Study
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Minimum Age: 14 Years
Maximum Age: 24 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Power Chain and Crimpable hook for En-masse retraction<br>Retraction will start on a 0.017x0.025 Stainless Steel wire using elastomeric chain ( force applied will be 212 g per side ) extending between the crimpable hooks and the miniscrew | Procedure: Power chain and Crimpable hook fro En-masse Retraction<br>* Retraction will start on a 0.017x0.025 stainless steel wire using elastomeric chain ( for applied will be 212 g per side ) extending between the cripmable hooks and the miniscrew<br>|
| Experimental: T-loop<br>Closing retraction T-loops will be fabricated using 0.017x0.025 TMA wire. The loop will be positioned halfway the extraction space and the canine. | Procedure: T-loop<br>* closing retraction T-loops will be fabricated using 0.017x0.025 TMA wire. The loop will be positioned halfway the extraction space and the canine.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Anchorage loss | Digitally scanned dental models taken pre and post completion of retraction will be measured by identifying landmarks and reference lines and planes ( measured in mm ) | from pre to post retraction/intervention ( an average of 6-8 months ) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retraction Rate | The antero-posterior movement of anterior teeth and first molars will be assessed by measuring the digitally scanned dental models taken of the patients monthly ( measured in mm ) | from pre to post retraction/intervention ( an average of 6-8 months ) | 
| Molar Rotation | Digitally scanned dental models that are taken before and after retraction will be assess the rotation of the maxillary first permanent molar in relation to a reference line ( measurement of the angles in degrees ) | from pre to post retraction/intervention ( an average of 6-8 months ) | 
| Pain of Intervention | each patient will fill a questionnaire regarding his treatment experience in a Visual Analog Scale (VAS) scoring from 1-10 by making a handwritten mark on a 10-cm line that represents a continuum between no pain on the left end (0 cm) of the scale and the worst pain on the right end of the scale (10 cm). The question-naire will include several questions related to oral hygiene, pain and discomfort experienced throughout the trial. | from pre to post retraction/intervention ( an average of 6-8 months ) | 
| Anterior teeth extrusion/intrusion | The principle investigator will examine pre and post Cone Beam CT ( CBCT ) in Relation to lines and reference planes ( measured in mm ) | from pre to post retraction/intervention ( an average of 6-8 months ) | 
| Anterior teeth torque | The principle investigator will examine pre and post Cone Beam CT ( CBCT ) in Relation to lines and reference planes ( measured in degrees ) | from pre to post retraction/intervention ( an average of 6-8 months ) | 
| Anterior teeth tip | The principle investigator will examine pre and post Cone Beam CT ( CBCT ) in Relation to lines and reference planes ( measured in degrees ) | from pre to post retraction/intervention ( an average of 6-8 months ) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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En-masse Retraction, Friction, Frictionless, CBCT, Anchorage, Anchorage loss, Dental models