Retention & relapce in orthodontics.pptx

Retention & relapce in orthodontics

1. PREPARED BY DR. WESAM GOUDA PhD IN ORTHODONTICS LECTURER IN ORTHODONTIC DEPARATMENT FACULTY OF DENTAL MEDICINE ALAZHR UNIVERSITY RETENTION & RELAPCE

2. RETENTION Defined by Moyers as “Maintaining newly moved teeth in position long enough to aid in stabilizing their correction”. Defined as loss of any correction achieved by orthodontic treatment Relapse

3. PRE-TREATMENT POST-TREATMENT RETENTION

4. PRE-ORTHO AFTER SERIAL EXT. POST-TREAMENT POST-RETENTION RELAPSE

5. Why is retention necessary?  Retention is necessary for 3 main reasons 1. The gingival and periodontal tissues are affected by orthodontic tooth movement and require time for reorganization when the appliances are removed . 2. The teeth may be in an inherently unstable position after the treatment,so that soft tissue pressures constantly produce a relapse tendancy . 3. Changes produced by growth may alter the orthodontic treatment.

6. If teeth are not in an inherently unstable position and if there is no further growth, retention still s vitally important until gingival and periodontal organization is complete. NB. Retention cannot be abandoned until growth is essentially completed.

7. Common relapse problems include: The appearance of crowding and rotation. b. The appearance of reappearance of spaces after full space closure particularly in extraction sites. c. A tendency for the return of Class II molar relationship with consequent over-jet appearance after reduction of Class II div. 1 malocclusions

8. Etiology of relapse: 1- Persistence of the cause: as oral habits ( thumb sucking, nail biting, tongue thrust, a bnormal swallowing. ,,, etc. 2. Tooth position: the teeth should be present at the area of functional tolerance at the end of orthodontic treatment. 3. Soft tissue: There are three soft tissue entities that may influence the stability of the tooth in its new position : a. The superalveolar (gingival group of fibers) b. The periodontal ligament. c. The muscles. As tongue and buccinator

9. 4. Bone: The alveolar bone surrounding a repositioned tooth is a functional tissue which generally responds to force. There is no evidence to suggest that bone will produce forces which may reposition teeth. Accordingly alveolar bone is probably not a causative factor in relapse. 5. Growth: Growth can be an important factor in retention-relapse because the active phase of treatment of many patients is completed while facial growth is still in progress. If a patient is in the retention phase of treatment during the last stages of facial growth, some changes inskeletodental relationship may occur.

10. Finishing criteria:- Proper axial inclination with artistic positioning of the incisors. Good buccal intercuspation. Good arch alignment. Good overbite and over-jet, accompanied by a good cephalometric interincisal angle. Good root paralleling, especially at extraction sites. Good arch form. Reasonably flat occlusal plane. Corrections of rotations. Continuity of tooth contacts. Unhindered functional movements. Finishing and retention

11. TYPES OF RETENTION 1- Natural or no retention as in Anterior cross bite Serial extraction Blocked out or highly placed canines in class I ext. cases Posterior cross bite in patient having steep cusps

12. 2- Limited or short-term retention As in: Class I non ext. cases Deep bite Class I, class II div. 1&2 cases treated by ext.

13. 3- Prolonged or permanent retention As in : Midline diastema Severe rotation Patient with abnormal musculature or tongue habits Arch expantion without good occlusion

14. Retention appliances

15. After completion of tooth movement, the bone trabeculae are reoriented again in the direction of the axis of the root of the tooth. This takes six month to complete. The bone is found to be more responsive to the influence of pressure where the occlusion will not hold the tooth in position; therefore, it is necessary that after active orthodontic tooth movement, the tooth should be retained in position by means of a retention appliance to prevent its relapse.

16. Retention appliances should be made simple as possible as the young patient is usually anxious by this time, to abandon orthodontic appliances. As a measure for retention, muscle exercises may be used either alone or in conjunction with appliance. It should be abandoning gradually and under supervision by having the patient progressively reduce the number of hours it is worn every day.

17. Retention appliances may be either removable or fixed. Occasionally, it is possible to use as a retainer the appliance which has actively corrected the malocclusion by rendering the appliance passive (as in cases of screws) so that it exerts no further pressure, or by substituting an appliance of simpler design which will hold the teeth in their correct position. A retaining appliance should be simple, efficient and should not interfere with the proper cleansing of the teeth and care of the soft tissue of the mouth by the patient.

18. HAWLEY RETAINER FOR UPPER AND LOWER ARCHES REMOVABLE RETAINERS

19. The activator: It can be used to maintain the relationship of the dental in any plane i.e. anteroposterior , vertically and transversely. It can also provide strong inter-maxillary anchorage to prevent unfavorable movement of the teeth and aids the reestablishment of muscle behavior.

20. CLEAR RETAINERS

21. FIXED RETAINERS BAND AND SPRU RETAINER BONDED LOWER RETAINER

22. BANDED CANINE TO CANINE RETAINER

23. The duration of retention: The period varies greatly in different cases, varying from few weeks to a year or longer, when we feel that the recently moved teeth of modified arches have been harmonized in function with all the forces to which they are subjected the appliances may be removed and the case should be kept under close observation.