Anchorage in orthodontics

Presentation for under graduate students.
read once and remember always.

1. ANCHORAGE IN ORTHODONTICS Presented By: Dr. Anil Godara

2. CONTENT: Definition Classifications Sources of anchorage Dental Implants Anchorage Planning Selection of Anchorage Anchorage loss

3. DEFIN I TION According to T.M. Graber “ The nature & degree of resistance to displacement offered by an anatomic unit when used for the purpose of e ffecting tooth movemen t ” According to White and Gardiner “ Anchorage is the site of delivery from which a force is exerted.”

4. According to the manner of force app l i ca t i on Simple anchorage Stationary anchorage R eciprocal anchorage According to jaw movement Intra-maxillary anchorage Inter- m a x illary anchorage According to the site of anchorage Intra oral anchorage Extra oral anchorage Muscular anchorage According to the number of anchorage unit Single or primary anchorage C o m pound anchorage Multiple or reinforce anchorage CLA S SIF I C A TIONS

5. SIMPLE ANCHORAGE Dental Anchorage in which the manner & application of force is such that it tends to change axial inclination of tooth or teeth that form the anchorage unit in the plane of space in which the force is being applied . Fig: Simple anchorage (Upper removable applience with reverse loop canine retractor for retraction of upper canine)

6. RECIPROCAL ANCHORAGE When the two with an equal root area or two similar groups of teeth are used to move each other reciprocally to an equal extent ( towards each other or in opposite direction s) ) Fig:Arch expansion using midline screw Fig: C ross elastic to correct molar cross bite (Cross bite elastic are used to push the maxillary molars labially and the mandibular molars lingually )

7. INTRA-MAXILLARY ANCHORAGE Anchorage obtained from a tooth or teeth in one jaw to move the tooth or teeth in the same jaw . Fig : Intra-maxillary anchorage , the anchor units (maxillary posterior teeth and the the teeth to be moved maxillary canine are present in the same arch ).

8. INTER-MAXILLARY ANCHORAGE When the teeth in one arch are used for anchorage to move the teeth in other arch. Fig: Class II inter-maxillary traction Fig: Class III inter-maxillary traction

9. EXTRA ORAL ANCHORAGE Anchorage in which the resistance units are situated outside the oral cavity is termed extra oral anchorage . Fig:Cervical headgear (it derive anchorage form cervical or cranial region) Fig: Facemask (it derive anchorage from facial bone )

10. MUSCULAR ANCHORAGE It makes the use of forces generate by muscles to aid in the movement of teeth. Fig: lip bumper makes of the tonicity of the lip musculature and enhance potential of the mandibular molars preventing their mesial movement ,

11. REINFORCED ANCHORAGE The anchorage units are reinforced by the use of more than one type of resistance units fig: Use of traspalatal arch in fixed mechanotherapy. fig: Anterior inclined plane: exerts a backward pull on the maxillary appliance through the mandible

12. STATIONARY ANCHORAGE Dental anchorage in which the manner &application of force tends to displace the anchorage unit bodily in the plane of space in which the force is being applied . Fig: pitting bodily movement of one group of teeth against tipping of another .

13. SINGLE OR PRIMARY ANCHORAGE The resistance provided by single tooth with greater alveolar support is used to move another tooth with lesser alveolar support. Fig: Molar being used to retract a pre molar

14. COMPOUND ANCHORAGE The resistance is provided by more than one tooth with greater support is used to move teeth with less support Fig: Retracting incisors using loop mechanics

15. SOURCES OF ANCHORAGE Sources Intra oral: Th e teeth. The alveolar bone 3.The basal bone 4.The musculature . Extra oral : Cranium (occipital or parietal anchorage) Back of the neck ( cervical) Facial bone .

16. THE TEETH When one teeth moves the others can Act as anchorage units,it depends on -Root form -Root size -No of roots -Root length -Root inclination

17. THE TEETH Root form: On cross section of roots can be of three types, round, flat and triangular. •Round roots as seen in bi cuspids and palatal root of maxillary molars can resist horizontally directed forces in any direction. •Flat roots for an example those of mandibular incisors and molars and buccal roots of maxillary molar can resist movements in mesio-distal direction. •Triangular roots of canine and maxillary central and lateral incisor offer the maximum resistance to displacement compared to round or flat root form.

18. THE TEETH Size and no . of root: Multi rooted with large root ha ve a greater ability to withstand stress than single roote d teeth. Root length: The longer the root the deeper it is embedded in bone and the greater is its resistance t o displacement. Inclination of tooth: The greater resistance to displacement is offered when the course exerted to move teeth is opposite to that of their axial inclination. Ankylosed teeth: Orthodontic movement of such teeth is not possible and they can therefore serve as excellent anchors whenever possible.

19. ALVEOLAR BONE Alveolar bone resist tooth movement up to its limit, beyond t hat it allow tooth movement by remodeling . Healthy alveolar bone-more anchorage .

20. BASAL BONE Certain areas act as resistance areas-provide good Anchorage-hard palate,lingual surface of mandible

21. MUSCULATURE H ypertonic labial musculature used for anchorage in lip bumper

22. Cranium (occipital or parietal anchorage:- anchorage obtained from occipital or parietal bone) Eg . Head Gear to restrict maxillary growth Cervical :- Anchorage from cervical or neck region Eg . Cervical Head Gear Facial Bones :- Face mask used to protract maxilla take anchorage from mandibular symphysis Eg . Reverse Head gear EXTRA ORAL ANCHORAGE

23. Mini dental implants: Used in patients having multiple lost teeth or hypodontia or to augment teeth with periodontal diseases. Classification : According to exposure of head- 1. Open –head is exposed to oral cavity – used when the implants is placed in an area where the soft tissues are not movable. 2. Closed-embedded under soft tissue –used when the implants is placed in an area where the soft tissue is movable.

24. According to implant placement: 1. Self tapping method: Implant tapped into a previously drilled hole – smaller diameter implants 2. Self drilling method: Implants itself drilled into the bone-larger diameter implants. According to path of insertion: 1. Oblique :30 to 60 degrees to long axis of teeth 2. Perpendicular: Inserted perpendicular to the bone surface

25. Mini dental implants

26. ANCHORAGE PLANNING factors affecting are:- 1)number of teeth being moved:-to move greater number of teeth, anchorage should be more 2)type of teeth:-teeth having more surface area require more anchorage 3)type of movement:-bodily movement require more anchorage 4)duration:-prolonged treatments require good anchorage 5)skeletal growth pattern:- a)vertical- require more anchorage due to poor tonicity of facial muscles b)horizontal-require less anchorage due to strong tonicity of facial muscles 6)occlusal interlock:- good occlusion=good anchorage

27. SELECTION OF ANCHORAGE: Since anchorage must be selected to make proper use of the space created by extraction, a more rational approach of classifying anchorage would be the one which guides the operator to make use of the available space. Accordingly, anchorage in mandibular arch can be put into three classes: DEPENDING ON ANCHOR LOSS EXPECTED: Minimum anchorage Moderate anchorage Maximum anchorage

28. Minimum Anchorage Minimum anchorage mechanics are selected when the mandibular posterior teeth may be permitted to migrate mesially into half or more of the extraction site.

29. Moderate Anchorage Moderate anchorage mechanics are selected when the mandibular posterior teeth may be permitted to move forward into one fourth to one half of the extraction site.

30. Maximum Anchorage Maxillary anchorage mechanics are selected when the mandibular posterior teeth may be permitted to move forward into no more than one fourth of the extraction site.

31. ANCHORAGE LOSS Anchorage loss in all 3 planes of sapce Sagittal plane: 1. Mesial movement of molars 2.Proclination of anteriors Vertical plane: 1.Extrusion of molars 2.Bite deepening due to anterior extrusion. Transverse plane:1.Buccal flaring due to over extended arch form, unintentional lingual root torque . 2.lingual dumping of molars .

32. THANK YOU