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Removable appliance lec 6,7

الكلية كلية طب الاسنان     القسم التقويم والاطفال وطب الاسنان الوقائي     المرحلة 4
أستاذ المادة لميس خضر محمد       05/04/2020 19:59:27
College of Dentistry 4th stage Lec.6 Orthodontic Dr. Lamis Khidher Mohammed Removable Appliances There are many types of orthodontic appliances according to the mode of action and type of attachment , by mean if it is removed or fixed in side patient mouth:- 1. Removable appliance.(R.A) 2. Fixed appliance. 3. Myofunctional appliance 4. Combination of fixed and removable. Removable orthodontic appliance Orthodontic devices that can be removed by the patient for cleaning and which may be designed to apply forces to the teeth by means of springs, screws and other mechanical components. The types of removable appliance :- It can be either ? Active: producing tooth movement by springs, screws, etc. or ? Passive: has no active component (retainer, space maintainer, habit breaker). Any removable appl. Made of the following :1. Stainless steel wires. 2. Acrylic. 3. Others: as screws and elastics. Action of removable orthodontic appliance: All the removable appl. Can produce only the following tooth movement: 1. Tipping tooth movement (labio-lingual or mesio-distal). 2. Tooth rotation less than 900 (couple force system). Advantages of R.A. : 1. It can be removed on socially sensitive occasions. 2. Short chair side time (because it is fabricated in the laboratory rather than in patient s mouth). 3. Its components are relatively cheap. 4. Simple (can be done by dental practitioner). 5. It does not make oral hygiene difficult since it can be removed. Disadvantages of R.A.: 1. Heavily dependent upon the patient co-operation. 2. Unable to perform complex tooth movements (limited to tipping and simple rotation) so can be used only to treat simple cases. 3. Few teeth move at one time. 4. Uncomfortable to the patient and affects speech in the first few days. Indications of R.A. in general : 1. Limited (tipping) tooth movements. 2. It may be used for space maintenance or habit breaking. 3. Correction of individual tooth malposition. 4. Arch expansion. 5. Retention (retainer) after comprehensive orthodontic treatment "fixed appliance". The Components of R.A.:- I. II. III. IV. Active components :which produce force for tooth movement. Retentive components: responsible for holding the appliance inside the mouth, as clasps. Acrylic base plate: as a major connector connecting the components. Anchorage.: It is an imaginary component resisting unwanted tooth movement. 2 Active components: classified according to the direction of the force and orthodontic tooth movement into:- 1. For labial (buccal) movement: a. Z-spring. b. Recurved Z-spring. c. T-spring. 2. For palatal (lingual) movement: a. Hawley arch. b. Robert s retractor (simple and sleeved). 3. For mesio-distal movement: a. Finger spring (simple and modified). b. Buccal canine retractor (simple and modified). 4. Additional active components , different directions: ? Screws and elastics. 1-For labial movement: 1.1. Z-spring: a. Shape:- It is ‘Z’ in shape. b. Location:- it is palatally situated c. Wire gauge :- 0.5 mm HS. d. Uses :-It is mainly used in: ? Correction of an anterior crossbite of single tooth by pushing it in labial direction. ? It is used to correct the rotation of one incisor ?900 together with Hawley arch (couple force system: labial force + palatal force). 1.2. Recurved Z spring: a) Shape:- It is a combination of 2 Z-spring joined at the anterior region to form one active arm. b) Location:- it is palatally situated. c) Wire gauge :- 0.5 mm HS. d) Uses:- It is used in the correction of crossbite of more than one incisor (2 incisors, or 3 incisors, or 4 incisors), and in the correction of mild rotation and irregularities of more than one incisor together with Hawley arch 3. T-spring: a) Shape :- it is T in shape b) Location:- :- it is palatally situated c) Wire gauge:- 0.5 or 0.6 mm HS. d) Uses :-it is used to push one posterior tooth in buccal direction (premolars). 2-For palatal movement: 2.1. Hawley arch: a. Location : it is labialy situated,it touch the most prominent teeth b. Wire gauge : 0.7 mm H.S. c. Uses: it is use for retraction of incisors (when the over jet 6 mm or less) and retention d. It is less flexible than Roberts retractor. 2.2. Roberts retractor: a. Shape: It consists of two sleeved buccal canine retractors joined at the midline. b. Location: it is labially situated. c. Wire gauge: 0.5 mm H.S. with sleeved distal arms , or 0.7mm H.S. at all. d. Uses: It is used for retraction of the incisors so reduce the over jet which is more than 6 mm; It is usually used in 2nd stage of treatment of class II division 1 malocclusion. 3-For mesio-distal movement: 3.1. Finger spring: a- Shape: It is finger like in shape. b- Location: it is palatally situated. c- Wire gauge: 0.6mm H.S. (simple) , 0.5 mm H.S. (guarded). d- Uses: it is used for mesio-distal movement of any tooth which is located There are two types: 1. Simple finger spring (self-supported finger spring). 2. Guarded finger spring (supported finger spring). 3.2. Buccal canine retractor (BCR). a- Location: it is buccally situated. b- Wire gauge: 0.7 mm H.S. c- Types : simple or modified. d- Uses: ? The simple BCR type used for distal movement of a mesially angulated canine which is located within the line of occlusion , while ? The modified BCR type used to move the mesially angulated buccally malposed canine distally and palatally. 4-Additional active components: 4.1. Screws: ? Screws may be designed to move a single tooth or groups of teeth. The direction of tooth movement is determined by the position of the screw in the appliance. 5 within the line of the arch. However it is mostly used for distal movement of canines. (couple force system). 3

المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .