Anchorage in orthodontics

1. 1 Anchorage in orthodontics Anchorage in orthodontics Prepared by: Prepared by: Dr. Mohammed Alruby Dr. Mohammed Alruby ناكرب فلا اهفوج يفو هتماص ضرلااف نايسن تمصلا نا نظت نا كايا ---- Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

2. 2 Anchorage in orthodontics Introduction: Source of anchorage: 1-Intra-oral 2-Extra-oral Classification of anchorage Types of anchorage 1-Intra-oral: a-Intra-maxillary b-Inter-maxillary 2-Extra-oral: Control of anchorage Reinforced anchorage Loss of anchorage Anchorage preparation in different techniques 1-Mershon technique 2-Edgewise technique 1962 3-Johnson twin wire technique 1932 4-Tweed technique 1941 5-Bull technique 1951 6-Begg technique 1956 7-Combination of Edgewise and Begg 8-Straight wire technique 1970 – 1972 9-Modern Begg ( Begg and Straight wire technique) Mandibular lower anterior segment anchorage enhancement. Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

3. 3 Definition: it is a resistance to overcome an applied force. According to the Newton’s law “to every action there is an equal and opposite reaction” when a given magnitude of force is applied to move a tooth, there will be apposite and equal force upon the anchor tooth. Each orthodontic appliance is composed of two basic components: 1-Active or force component. 2-Resistance or anchorage component. For each forces, there will be a counter effect therefore it is very important in orthodontic to design and prepare the anchorage units against which teeth will be moved before application of force. Usually the segment of the dental arch utilized as an anchorage unite is intended to be maintained stationary but in biologic sense, there is no stationary dental anchorage. Source of anchorage; a-Intra-oral; depend on: 1-Root surface area: The surface area of the root indicates the anchorage value of the tooth. Resistance is directly proportional to the root surface area The length and shape of the root are the factors in determining root surface area Longer root offers greater resistance than the shorten root. Triangular root surface offers greater resistance than the flat roots. 2-The bone in which teeth are situated: The cortical bone offers greater resistance to movement than other bone, so that it is important to anchor the tooth against the cortical bone (by incorporating buccal buccal root torque) 3-The direction of force relative to the direction of growth: The teeth offer more resistance if the movement is opposite to the direction of natural growth of the teeth = greater resistance is offered by distal movement of molars than mesial movement. = greater resistance is offered to palatal than buccal movement of the teeth = intrusive movement than extrusive based upon the fact that the general direction of growth is outward and occlusally. 4-Types of tooth movement: Greater resistance is offered to bodily than tipping movement so that, the anchor teeth be prepared in such a manner that if they would move, should move bodily to increase their resistance, this can achieve by incorporating tip back bend (30 degree) to the occlusal plane just mesial to the anchor 1st molars. 5-The muscular pressure: The muscular pressure can offer active resistance to tooth movement, the idea is utilized in functional appliance. Example: lip bumper is used to reinforce the anchorage value of 1st molars 6-Stabilizing plate: Which engage the oral mucosa and inter dental spaces. Tissue born anchorage used in removable orthodontic appliances 7-Proper inter-cuspal of the teeth: Can considered as a source of anchorage, so that correction of the buccal segment and maintenance of proper intercuspation is very important before correction of anterior segment. Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

4. 4 b-Extra-oral (the bone of skull): Cervical, parietal, frontal, occipital anchorage. c-Muscular: as lip bumper Classification of anchorage 1-According to source of anchorage: a-Intra-oral anchorage; which may be Solzman 1957 = tooth born: involving tooth as an anchorage unites that may be intra-maxillary or inter- maxillary (Baker type) = soft tissue born; involving the palate, oral mucosa and utilized in use of removable appliances b-Extra-oral anchorage: Utilize the bones of skull as a source of anchorage by the use of extra-oral appliances as headgear, extra-oral anchorage may be: 1-Cervical from neck region as neck strap 2-Occipital from occipital bone as occipital headgear 3-Parietal from parietal bone as high pull headgear c-Muscular: anchorage derived from action of muscles 2-According to the involved jaw: a-Intra-maxillary; one or more than one tooth is used to move one or more than one tooth on the same jaw as; Class I elastics b-Inter-maxillary (Baker anchorage): one or more teeth in one jaw are used to anchor the movement of one or more teeth in the opposite jaw, as Class II, III, and cross elastics. 3-According to the manner of force application; Kesling 1989 (1)-Simple anchorage: resistance to tipping force and if the anchor tooth cannot withstand the force, it is freely to tip (2)-Stationary anchorage: Resistance to bodily movement or translating force. The anchor tooth or teeth must be stationary and if moved, must be moved bodily but in biologic sense, no stationary dental anchorage and it is difficult to obtained Stationary anchorage can be only obtained extra orally from the skull bones as they do not move when the forces is applied NB: stationary anchorage is a relative term which is depend on: 1-Character of bone in which the anchor teeth are located and through which the tooth or teeth are to be moved, spongy bone with large osseous spaces or poorly calcified bone will not offer as much resistance to force as will calcified bone. 2-Teeth which have been loosened by trauma should not be used 3-Inter-maxillary elastics should be not used on teeth undergoing root calcification in the early mixed dentition. 4-Interfarence of muscles with the direction in the tooth is to move, such as the lower lip pressing on the lingual surface of the maxillary incisors 5-The degree of force; strong force will move the anchor teeth (3)-Reciprocal anchorage: Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

5. 5 Reciprocal force is applied between two or group of teeth to be moved in opposite directions 4-According to the number of anchorage units: 1-Single or primary anchorage: one tooth is used to anchor the movement of one tooth 2-Compound: two or more teeth of greater support are used to anchor the movement of one or more teeth of lesser support 3-Reinforced: the addition of non or dental anchorage sites as oral mucosa, circum oral muscles and bones of skull 5-According to proper use of the space created by extraction in the arch: I-Minimum anchorage: Mechanics: involve a reciprocal anchorage between anterior and posterior teeth without any effort to reinforce the anchorage at posterior anchorage units Uses: 1- when the posterior teeth are permitted to migrate mesially into one half or more the extraction space. 2- when there is slight curve of spee and no intrusion of the lower incisors is required. 3-The lower 1st molars are need to be moved anteriorly to correct the molar relationship II- Moderate anchorage: Mechanics: involve placing of an active thrust on the anchor teeth anchor teeth causing bodily resistance at this area this can be achieved by placing tip back bends in the anchor wire just mesial to the molar tubes. Uses; 1- when posterior teeth may be permitted to moves forward one fourth to one half of the extraction space. 2- when there is a moderate crowding. 3- when there is a moderate curve of spee. III- Maximum anchorage: Mechanics; involve reinforce the anchor teeth with all available means and reducing the work load upon them by developing forces outside the mandibular arch as; inter-maxillary, extra-oral, or muscular anchorage, extra-oral inter-maxillary combination as; Class III elastics. Reinforce by headgear on maxillary arch uses: when the mandibular posterior teeth may have permitted to moves forward not more than one fourth of the extraction space, it is planned when the extraction space is just enough to relief crowding anterior to the 1st permanent molars. Types of anchorage (1)-Intra-oral anchorage: which may be inter or intra-maxillary. Intra-maxillary anchorage: A-Simple intra-maxillary anchorage: 1-single simple intra-maxillary anchorage; in which a tooth with greater support is used to anchor movement of the tooth with lesser provided that both teeth are freely to tip. The anchor teeth may be tipped if cannot withstand the resistant of moving teeth. 2-single compound intra-maxillary anchorage: a number of teeth with greater support are used to move a tooth or teeth with lesser support in the same arch provided that, both anchor teeth and teeth to be moved are left freely to tip. B-stationary intra-maxillary anchorage: Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

6. 6 1-stationary single: a tooth with greater support is used to move bodily a tooth with lesser support provided that, the anchor tooth should remain stationary and if moved should move bodily, when make tip back bends in the molar region make more resistance to tipping. 2-stationary compound: more one tooth with greater support are used to move bodily one or more teeth with lesser support provided that the anchor teeth should remain stationary and if moved should move bodily C-Reciprocal intra-maxillary anchorage: Which is simple that may be, single or compound or stationary that may single or compound. 1-Reciprocal simple single: one tooth to be moved is used to anchor movement of another tooth in the same arch, provided that both teeth are freely to tip as in closing the median diastema between the inclined maxillary incisors. 2-Reciprocal simple compound: more than one tooth to be moved are used as an anchorage to move more than one tooth and teeth to be moved are left freely to tip as closing the diastema by moving the central and lateral incisors on the both sides toward each other 3-Reciprocal stationary single: one tooth to be moved bodily is used as an anchorage to move tooth bodily in the same arch as open coil spring placed on rectangular arch wire between two canines to make distalization of them. 4-Reciprocal stationary compound: more than one tooth to be moved are used as an anchorage to move bodily more than one tooth as posterior palatal expansion by using expansion screw Inter-maxillary anchorage: A-Simple inter-maxillary anchorage: 1-Simple single: tooth with greater support in one arch is used to move tooth with lesser support in the opposite jaw provided that, both teeth are freely to tip 2-Simple compound: more than one tooth with greater support in one arch are used are used as an anchorage to move one or more teeth in the opposite arch, provided that both anchor teeth and teeth to be moved are freely to tip. B-Stationary inter-maxillary anchorage: Is usually compound in which all teeth in one jaw are used to move bodily a tooth with lesser support in the opposite jaw.as retraction of lower canine by using Class III elastics withy upper arch that has no extraction space C-Reciprocal inter-maxillary: 1-Simple single reciprocal inter-maxillary: a tooth to be moved in one arch is used to move a tooth in the opposite arch, provided that both teeth are freely to tip as cross elastics for correction of cross bite 2-Simple compound inter-maxillary: more than one tooth in one arch are used to move more than one tooth in the opposite arch, provided that, both are freely to tip and have an equal distance as in Class III elastics or anterior inclined plane for correction of anterior cross bite. 3-Stationary compound reciprocal inter-maxillary: in which a reciprocal inter-maxillary force is applied between maxillary and mandibular arches to move them in opposite direction as in activator. (2)- Extra-oral anchorage: Involving the use of extra-oral sites either to move or to anchor movement of teeth, it can be used in combination of any orthodontic appliance. = sites and appliance used: Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

7. 7 1-Cervical: cervical neck strap The primary vector of force provides distal and extrusive movement so that it is the best choice for treatment of class II deep bite 2-Parietal: high pull headgear, the primary vector provides an intrusive movement with less distal movement and is the best choice for treatment of open bite cases. 3-Occipital: oblique headgear, the primary vector of force provides an intrusive and distal movement, so that it is the best choice for treatment of class II open bite cases. = for the anchorage purpose, the appliance is worn 12/h/day at least with force twice than that delivered by intra-oral appliance ---- this type of anchorage may be purely stationary. = uses; 1-When anchorage required to be maximum 2-Provide an additional support to intra-oral anchorage 3-Prevent procumbancy of incisors 4-To distalizing the dental arch or teeth (((Reinforced anchorage))) That type of anchorage in which more than one type of resistance is involved in order to maximize anchorage unites, it involve the non- dental anchorage sites which are used to reinforce or increase the resistance of dental anchorage unites, it may be obtained from: 1-Oral mucosa: == all acrylic plates which fit the palatal and lingual mucosa == Nance palatal arch 2-Extra-oral anchorage sites 3-Muscular anchorage: involve the action of masticatory and orofacial muscles either to produce or to anchor teeth movement by use the functional appliance as; oral screen and lip bumper The reinforced Anchorage can be obtained by: 1-Edgewise with2nd order bends 2-Passive lingual arch 3-Trans palatal arch 4-Combined labial and lingual arches 5-Reduction of number to be moved 6-Pitting the maxillary arch against the mandibular arch in class 2 malocclusion case should be taken to stabilize the anchorage by the addition of extra-oral force when required Control of anchorage = in clinical application of anchorage care must be taken to control the anchorage unite and to ensure maximum stability of anchorage teeth, the anchorage loss may occur which may complicate the treatment = stability of anchorage depends on the careful selection of anchorage unite The following factors are very important in selection of anchorage unite: 1-Surface area of the root: teeth with greater surface area of roots are more resistant 2-Character of alveolar bone: compact bone is more resistant than the spongy bone, which have more intra-osseous spaces and poorly calcified 3-Periodontal condition of the tooth: traumatized or periodontally affected teeth should not be selected 4-number of teeth: select large number of teeth in the resistant part of the appliance Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

8. 8 5-Axial inclination of the teeth; the axial inclination of the teeth to be used as anchorage is better to present against the direction movement 6-Shape of the root: longer root is better than shorter one, and triangular or conical root is better than flat one 7-Force generated during function: should be favors the teeth movement and stabilize the anchorage, include: force of occlusion, muscle force, growth force. 8-the amount of force delivered by the appliance: there is a variation between the active and resistance parts of the appliance so, the periodic reevaluation of the anchor unite is very important. (heavy force may result in movement of anchor tooth) 9-inter-cuspation: teeth with maximum inter-cuspation are more better 10-periodic reevaluation; if recognized any anchorage loss, stop forces and reinforce the anchorage with the available means that is previously described Anchorage loss = when the anchor teeth show change in position they should be allowed to return to their original positions or actively moved to proper position before continuing treatment = when multi-banded appliance and rigid arch are used the degree of resistance in the anchor teeth to inter-maxillary force is increased = when maxillary arch is pitted against the mandibular arch in order to obtain distal movement of the maxillary teeth, there is no way to ascertain in advance the extent of resisting forces that may be attributed to either of these arches Anchorage preparation in different techniques Anchorage preparation is very important step for successful orthodontic treatment Regardless to the classification of the case, the anchorage requirements will be determined by: 1-The total work load upon the anchorage units: as the work load is high, the anchorage value should be increase as well as prevent anchorage loss, the work load can be minimized by: =reducing the number of teeth to be moved at particular time, however this is not always possible because the incisors should be retracted as one unit. = another alternative is by developing forces outside the arch through the using of inter- maxillary, muscular or extra-oral anchorage. = reinforcement of anchorage unit by all possible means (that previously described) 2-The available space within the arch: according to the proper use of the available space anchorage may be classified to: a-Minimum anchorage; in which the posterior teeth are permitted to move forward into one half or more of the extraction space, no attempts are made to reinforce the anchorage unit. b-Moderate anchorage: in which the posterior to move forward into one fourth to one half of the extraction space, 2nd order bend is incorporated into the wire to increase the resistance of anchorage units. c- Maximum anchorage: in which the posterior teeth may be permitted to moves forward, not more than one fourth of the extraction space, reinforcement of all anchorage with all possible means is necessary Lingual technique Mershon 1908 This technique utilized the use of maxillary and mandibular rigid arches for anchorage The mandibular arch was used to produce tooth movement in the maxillary arch by means of inter- maxillary elastics using the principles of Baker anchorage. Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

9. 9 Edgewise technique- Angle (1926) Regardless to the classification of the case, the anchorage requirement will be determined by: 1-The total work load upon the anchorage unit 2-The available space. The work load can be required by reducing the number of the teeth to be moved at the same time, but its limitation is that the incisors should be retracted as one unit as the work load is high, the anchorage value must be high too. According to proper use of available space, anchorage may be classified into: 1-Minimum anchorage requirements: in which the posterior teeth are permitted to move into one half or more of the extraction space (closing forward) involve reciprocal force between teeth and anterior teeth. 2-Moderate anchorage requirement: in which the posterior teeth may be permitted to move forward one fourth to one half of the extraction space. Anchorage value of posterior teeth should be high in this case by incorporating: == tip back bends at the molar region == active root thrust == palatal bar. == lingual arch == trans-palatal arch == Nance palatal arch == 2nd molar tooth involved in the anchorage unit 3-Maximum anchorage requirements: in which the posterior teeth may be permitted to moves forward not more than one fourth of extraction space in such cases, the anchor teeth must be reinforced with all available means by:  reduction of teeth to be moved  inter-maxillary anchorage, combination of more than of the appliance for the moderate type extra-oral or muscular anchorage  extra-oral, inter-maxillary combination N:B order bends if edge wise technique: 1-1st order bends: made in horizontal plane, offset, inset in labiolingual direction (toe in) Baynot bends: the 1st and 2nd molar offset (toe in) 2-2nd order bends: made in vertical plane, include: Esthetic bends: artistic bends, for adjusting the incisors roots Gabel bends: for adjusting the roots at the extraction sites Tip back bends: for uprighting the molars. 3-3rd order bends: limited to the rectangular wires, along its axis, which include: Active labial torque at the anterior segment Harmonizing torque: at the buccal segment Progressive torque: for uprighting the molar segment. Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

10. 10 Johnson twin wire technique 1932 The most disadvantage of this technique is, less control of anchorage in the extraction cases. Johnson advocated the use of: 1-Lingual upper and lower arches used to stabilize the molars and carry the auxiliary springs; these arches should be rigid enough and soldered to the molar tubes, and must be get passively to prevent undesired movement of the molars = the lower lingual arch should be contact the gingival margin of anterior teeth to provide an anchorage when Class II elastics inter-maxillary are used 2-Coil spring is used mesial to the molar bend to prevent any mesial movement of the molars 3-Head gear used during mixed and permanent dentition on the maxillary arch. Tweed technique – 1941 Tweed observe that, for achievement of harmony in occlusal and facial pattern, the mandibular incisors should be present in correct position over the basal bone of the mandible. In mixed dentition therapy: 1-Stop loops against molar tubes and preserve arch length 2-Tip back bends at canine,1st, 2nd deciduous molars and 1st permanent molars area, after anchorage preparation for upper and lower arches; placement of the stabilizing arches with tip back bends and stop loops are incorporated in the posterior segment. In permanent dentition therapy: According to tweed, the anchorage preparation is the first and most important step in treatment of malocclusion Tweed first prepare the anchorage in the mandibular arch and then moves the mandibular teeth into correct axial inclination; after that the lower arch is used as anchorage for the movement of the upper arch = tweed tip the buccal teeth lower distally by using Class III elastics in conjunction with head gear on maxillary molars to prevent their forward movement, the last mandibular molar teeth are not tied to the arch wire to prevent their roots from moving mesialy while tipping their crown distaly = thus the change of axial inclination of mandibular teeth (buccal) are prepared creating what is called (toe hold) to resist the tendency of forward shifting when Class II elastics are used = tweed also make active root thrust in the mandibular buccal segment. Bull technique, -- 1951 This technique was developed for extraction cases in permanent dentition in Class II and bi-maxillary protrusion when 2nd molars are fully erupted Introduce by Bull 1951 and has the following philosophy: = arch width cannot increase by expansion except in cases of actual collapse and cross bite = the arch length cannot be increase successfully where crowding of teeth is present = the arch length should be maintained or oven may be decreased during treatment = avoid use of arch wire bends which is difficult to duplicated in the same manner in subsequent arches = when necessary to tip the tooth change the position of bracket. Anchorage preparation depend on the good control of force required as follows: 1-Treatment is divided into stages so that an adequate number of resistance units are opposed to a minimum of malposed teeth; this ensure that the resistance unite will not move further than desired while malposed teeth are corrected. Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

11. 11 2-Each stage is completed before start the next 3-Use of bite plate to prevent occlusal interference during canine retraction. = 2nd order bends are not used in this technique except for the 2nd molar anchor tooth = Russel locks are used as molar stops against the molar tube and by use of Class II elastics will help to prevent forward movement of molars Light wire technique 1965 (Begg technique) Begg technique do not utilize the extra oral anchorage except in extreme cases, because the differential force control and tip back bends incorporated into the arch wire, all of these help stability of molar during treatment. =This technique utilizes the differential tooth movement concept, that depends on dividing bodily tooth movement into two stages, tipping movement followed by uprighting movement, this process facilitates tooth movement bodily with minimal resistance and anchorage loss. = this technique based mainly on the differential force concept in which, there is vertical loops occasionally with helical are made in the light wire to allow: 1-Engagement of the arch wire without excessive force applied 2-Reciprocal action between incisors 3-Wire is more resilient so the force is light with long duration 4-Minimize the load on the anchorage unit so the stability of molars is maintained during the stage of treatment and no need for extra-oral anchorage. (also use small bracket to increase inter-bracket distance which make the appliance more resilient) Molars anchorage bends: = this bend causes the wire to exert force on the molar so that their occlusal pressure on the mesial side of the tooth and gingival pressure on the distal side of the tooth, these two pressures on the molars tend to cause extrusion of the tooth at the mesial cusp and intrusion of the distal cusp. = tip back bends are inserted in the molar area to prevent mesial tipping of the molars and help stability of anchorage throughout treatment. = the amount of tip back wire varies from 10 to 40 degrees and this depend on the degree of over bite = tip back should be maintained in the plain as well N:B: according to objectives of 1st and 2nd stages of treatment in Begg technique only small amount of anchorage required, but 3rd stage need large amount of anchorage due to at this stage there is a correction of the axial inclination of the teeth. Toe in bends: = These are anti-rotational bends incorporated in the same point of anchorage bends, they are about 5 degrees in the same plan of arch wire = it prevents rotation of the molars to Class II elastics Variation in the angulation of anchorage bends The angle of anchorage bend is influenced by the following: 1-Stage of treatment: the anchorage bends used in 1st stage of treatment is lesser than that of 2nd stage and more bends required at 3rd stage of treatment 2-Depth of over bite: a-In average or deep bite cases, the degree of anchorage bend in the initial arch wire should be such that the anterior segment of the wire will rest passively at the depth of mucobuccal fold, when the wire inserted in the molar tube. b-The degree of anchorage bend used in open bite cases in only the amount required to keep the anchor molars of both jaws upright against the mesial pull of the wire. Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

12. 12 c-After end of treatment of over bite cases, the degree of anchorage bend should be reduced as necessary to prevent development of excessive open bite or distal tipping of molars. 3-The rate of progress of the case: If the correction of over bite and class II relationship is unsatisfactory it may be helpful to increase the anchor bend beyond normal 4-The inclination of anchor molars at commencement treatment: = if one or both molars are inclined mesially, the anchorage bend should be reduced proportionally so that the wire will rest passively in mucolabial fold = if the mesial inclination is severe, no anchorage bend required for the wire to rest passively in the mucolabial fold 5-2nd stage mechanics: It is good practice to observe the rule that any remaining tip back force should be reduced to that required for anchor molars to remain upright and exert bodily resistance against the mesial pull of 2nd stage elastics Variation in the location of the anchorage bend The location of the anchorage bend influenced by the following: 1-Stage of the treatment: a-In 1st stage of extraction treatment, the anchor bend is placed forward of molar tube as far as to permit it to slide back to the tube during space closure b-In 2nd stage, the anchorage bend can be placed far enough forward to assure that all spaces will close before the anchor bends reach the molar tubes c-In 3rd stage, if the anchorage bend is used it should be placed at the mesial end of the molar tube, provided that, the bicuspid bracket and molar tube at the same height. 2-Depth of over bite: The anchorage bend located close to the molar tubes is more effective for intruding anterior teeth during over bite correction than on farther forward. 3-Location of anchorage bends in non-extraction cases: In these cases, the anchorage bend should be placed nearer to the tube because greater hazards of occlusal impingement in these cases due to: = patient do their heaviest chewing in the region of the 1st molar = the mesio-distal length of 1st molar is greater than that of bicuspid, when the molar is absent, the extraction space is larger and the arch wire is unsupported over a longer span of space 4-Location of anchorage bend in 2nd bicuspid extraction cases: The bend is placed 2 to 3mm near to the tube and then more forward as required during space closure. Combination of edge wise and light wire technique Tweed, Fogel, Megill,Rickets This technique combined certain aspect of edge wise and Begg technique = light wire for initial stage of treatment and rectangular in the later stage = has three stages, tipping, uprighting and general alignment of teeth, axial positioning of teeth Anchorage preparation: = tip back bends about 60 degrees distal to premolar brackets = maxillary stabilizing plate is soldered to the maxillary molars to stabilize the anchorage. Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

13. 13 = head gear can be used to increase the anchorage. Straight wire technique 1970 (modified edge wise) History: = Angle 1932: change the position of molars tube to modify the angulation between tube and long axis of molars = tweed, Rickets: introduce pretorqued brackets = 1970—1971 Andrews incorporate 1st, 2nd, 3rd, order bends with normal key of occlusion = Roth: do overcorrection Because of complex forces that act on the teeth just when the wire is inserted due to complex movements of teeth. The anterior teeth have a greater tendency to tip forward and the anchorage demands will increase in buccal segment, so early control is recommended by use of: Palatal bar, -- transpalatal arch, -- lingual arch, -- Nance appliance, -- extra-oral force Modern Begg technique This is a combination of Begg technique (light wire) and modified edge wise (straight wire technique), there are two types of anchorage: 1-Dynamic anchorage: Is established by an intricate interrelationship of appliance force and physiologic force Appliance force: One-point contact, anchor bend action, arch wire action, auxiliary wire action as for extrusive force, intrusive force, and rotational force Physiologic force: Muscle, cuspal interlock, occlusal force, tooth morphology, bone density = dynamic anchorage is suitable during the early period of treatment, when light round wire is used to initiate tooth movement. In this stage the force of appliance and physiologic force combine to initiate the degree of tooth movement. 2-Static anchorage: Becomes important as the treatment progress into the torqueing and uprighting as in stage III and IV, when the amount of anchorage loss increase due to the increase in force levels within the appliance The static anchorage is provided by using: heavy arch wire, lingual arch, extra-oral head gear, early banding of 2nd molars and premolars. == Type of anchorage used with each stage of treatment is shown as: Stage I:-------------- dynamic Stage I:--------------dynamic Stage III:------------dynamic and static Stage IV:------------static. N:B: development of anchorage: 1941: Tweed and others applied a differential anchorage concept with the edge wise appliance by using series of arch wires with tip back bends in buccal segment. 1970: Begg and Edgewise appliance were used most commonly used appliance in orthodontics 1977: Begg and kesling use Ribbon arch allowed him to produce the tipping mechanics without 2nd order bends. Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

14. 14 1985:Hocevar introduce combination of Begg and Edgewise system so it called (BEDDTIOT) Begg, Edgewise Totally individualized Orthodontic technique, this system provides anchorage for bite opening and retraction mechanics. 1988—1996: Thompson and Zuriarrian advocated the use of combination of more than one system to ensure more anchorage control 1998: Preston et al made some modification to the bioprogressive therapy and introduce the use of certain wires to shape the arches Factor affecting anchorage requirements: 1-Nature of malocclusion: High discrepancy demands maximum anchorage to close extraction spaces Increased over jet and bimaxillary cases demands maximum anchorage during retraction 2-Craniofacial pattern: Either horizontal or vertical pattern, as in patient with open bite tends to lose anchorage than deep bite cases, so patients with less biting force lose anchorage than good biting force. 3-Type of tooth movements: Anchorage varying according to type of tooth movement as, bodily movement require more anchorage than tipping movement, Preadjusted bracket require high demand of anchorage during initial stage of treatment. 4-Friction: Friction between wires and bracket slot add resistance against tooth movement that give load to anchorage unit Anchorage designs 1-Transpalatal arch (TPA): Introduced by Robert A Goshgarian, Between upper 1st molars right and left with an Omega loop at the midline, it may be fixed or removable. Fixed: 0.036 inch stst wires contact the bend at mesio-lingual line angle. Removable: 0.032 inch round TMA or Elgiloy Function: 1-Molars stabilization and anchorage. 2-Correct molar relation 3-Molar distalization and molar torqueing 4-Vertical control by intrusion of molar by place Omega loop in mesial direction and increase the clearance in palatal area --------- tongue pressure allow intrusive force. 2-Trans-lingual arch: = used in mandible, 0.036 inch stst wire extended along the lingual contour of mandibular dentition from 1st molar in one side to 1st molar of other side = an adjustment loop can be placed in region of second deciduous molar or second premolar. 3-Nance palatal arch: = used in upper arch 0.036 inch stst, connecting upper 1st molars in both sides with acrylic part, rest on anterior segment of palatal area Function: sagittal anchorage reinforcement and prevent mesial movement of upper 1st molars. 4-Modified Nance button: Nance button attached to 1st molars on one side and premolar in other side 5-Vertical holding appliance: Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

15. 15 = modification of Nance appliance with an acrylic pad. = bands of 1st molars on both sides connected with 0.040-inch chrome cobalt wire with acrylic button on sagittal and vertical level at gingival margin of molar bands = four helixes are incorporated in wire to increase flexibility. = presence of acrylic button to enhance the intrusion force exerted by the tongue, this is useful in high angel cases when the prevention of eruption of posterior segment is difficult. 6-Utility arch: Continuous wire extended across the buccal segment, engage two molars and two incisors (2X2) or two premolars and four incisors (2x4). Used as, space maintainer and to prevent mesial movement of molars Formed from 0.016x0.016 inch stst ------------ Rickets Modern recommendation 0.016 x0.022 or 0.017x0.025 stst wire 7-Mini implant and skeletal anchorage system: TAD provide excellent anchorage source Factors affect tooth as anchorage unit: 1-Root form (cross section): The root form indicates the direction of the stresses that the tooth can resist = round cylindrical root: roots of lower premolars and lingual root of upper molar, the resistance is the same in any direction = flat root: root of lower incisors and lower 6 and buccal root of u 6, the resistance to movement is mainly in mesio-distal direction, but also there is a little resistance in buccolingual direction. = triangular root: root of upper incisors and upper and lower canines, the resistance to movement is mainly in mesio-distal and labial direction but also there is a little resistance in lingual direction. 2-Size and number of roots: The size and number of roots indicate the ability of the tooth to withstand stress The resistance to movement is directly proportional to the root surface area, so the greater surface area, the more periodontal fibers that increase the tooth stability and resistance to movement. The most preferable anchor tooth is that with large size and number of roots as, u 6 and E Large flat root of molars offers more resistance to movement than small flat root of incisors although are designed to resist movement from the same direction. 3-Root length: The resistance to movement is directly proportional to root length as: the longer the root the greater will be the resistance to dislodgment as u 3 which is deeply embedded in bone. 4-Tooth position in dental arch: As mandibular 2nd molar without root length is located between two high ridges of basal bone (mylohyoid and external oblique ridges) because this position seems to offer more resistance to bodily mesial movement than any other tooth. 5-Axial inclination of the teeth: The inclination of the teeth is important in assessing its value as source of anchorage, when the axial inclination is in a direction opposite to the force acting on the tooth, this will offer a greater resistance to dislodgement, this because part of the force is expanded down the axis of the tooth to the bone beneath. 6-Cuspal interlocking of opposing teeth: A good intercuspation with presence of well-developed high cusps can offer more resistance to orthodontic treatment for the anchor teeth 7-Teeth undergoing active growth: Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

16. 16 These teeth offer more resistance to movement opposite the direction of natural growth. 8-Mutual support: Each tooth in the arch is supported by contact with another except the last molar. A mechanism of adjustment to wear, the anterior component of force normally keeps these teeth in light contact, thus no tooth can be considered as anchorage without also considering its relationship to other teeth in the arches. Factors affect selection of anchorage 1-The available space: Proper analysis of the case (either extraction or non) will provide the orthodontist with available space to rearrange or to retract the remaining teeth other than anchor teeth 2-The applying forces: Any type of force applied on the anchor tooth will cause a varying degrees of movement of this tooth depending on the type and magnitude of this force: a-Intermittent force: as in case of using vertical tension loops, developed bodily forces b-Torqueing forces: when applying torqueing force to move the roots lingually, there will be additional work load requirement on the anchorage to resist the tendency of the crown to move labially. ((((Mandibular anterior Segment anchorage enhancement))))) = the labiolingual position of lower incisors is largely controlled by the tongue and lower lip position and function = Tweed stated that, the mandibular incisors should be kept in an upright position on the basal bone if proper function, esthetics and post retention stability to be maintained = this concept will increase demands for anchorage reinforcement in this area so any alteration in mandibular inter-canine width will be followed by relapse. Anchorage control: limiting certain unwanted tooth movement while encourage others. Principles of reinforcement: more than one type of resistance are involved in order to maximize anchorage and provide more control over the anchorage units Dental arch includes: Tip back mechanics, Passive lingual arch, Increase number of anchorage units, Decrease number of teeth to be moved, Labiolingual rigid stabilizing arch. Auxiliary anchorage includes: Headgear, Palatal bars, Lingual bars, lip bumper Procedures: = during levelling and alignment = during forward space closure =during distalization of molars = during class II elastics mechanics = during activator therapy 1-During levelling and alignment: Used to restrict undesirable changes during the initial phase of treatment, control is occurring in several directions as: == in sagittal direction: During levelling and alignment, the anterior teeth have tendency to tip forward and this effect more pronounced with pre-adjusted system due to the tip that built into canine, so use 0.010 Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

17. 17 figure 8 ligation extending from distal molar bonded to the canine in both sides that prevent canines from tipping forward Do not use elastics because the elastic force need more anchorage and is high than the levelling force, which lead to tip and rotate of anterior teeth distally leading to deepening the bite and exaggerate curve of spee == in vertical direction: = During levelling of deep bite cases there is a temporary increase in over bite as in Preadjusted appliance as canine is more tipped distally, so the mesial aspect of bracket slot directed incisally, so when wire is passes through these bracket will tend to lie more incisally than the incisors bracket, that will cause extrusion of incisors when wire engaged. ----- SO, avoid bracketing of incisors at the initial stage of treatment AND lace backs of canines to allow some correction of roots. = avoid early engagement of canine bracket with wire in the initial stage that may lead to intrusion of incisors and premolars. But only the canine ligature wire or elastics threads with very light force. = When levelling curve of spee, if the length of clinical crown of incisors is normal so should only do extrusion of posterior segment (2mm to occlusal plane distance) = the majority of mechanics is reciprocal in nature, so we can use the following mechanics: 1-Reverse curve of spee nitinol 0.016X0.016 and we can resist the intrusive effect on incisors by: a-Increase number of anchorage anterior units: involved canines and passive rectangular arch under anterior bracket b-Use of rectangular wire to prevent tipping movement c-Use more light force to allow extrusion of posterior segment. d-Use of vertical box elastics or magnets to allow extrusion of posterior teeth. 2-Using of maxillary bit plane: == in lateral direction: = must keep the lower inter-canine width as close as to the starting dimension. 2-During forward space closure: During correction of Class II molars relationship, should move the molar segment in forward direction by greater lingual force, that lead to incisors retroclination, we can prevent this undesirable effect by: 1-Increase number of anchorage units by involve six anterior teeth with premolars 2-Using 0.018 stst arch wire that allow 1st molar to freely tipped forward with less friction and inclination of 1st molars can be corrected later by tip back mechanics 3-When using rectangular wires so need lingual torque in lower incisors to increase the anchorage 4-Decrease number of teeth moved. 5-Use of class II elastics may minimize the anchorage demands upon the lower incisors. 3-During distalization of mandibular molars: = during treatment, some cases need distal movement of lower molars to create space in lower arch. This movement is very difficult to be carried out and may cause excessive Proclination of incisors. To prevent this effect, do: a-Maximize anchorage in anterior segment b-Use cervical headgear in lower molars c-Use lip bumper with heavy rectangular wire with lower anterior root torque. Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

18. 18 d-Maxillary headgear applied directly on upper molars and transmit the force directly to lower molars through class III elastics. 4-During Class II elastics mechanics: = during class II elastics application, there is Proclination and flaring in lower incisors, this can be reduced by: a-Using heavy stabilizing rectangular wire b-Placing labial root torque in lower anterior teeth ((Tweed advocated using tip back and Class III elastics)) 5-During activator therapy: In class II cases using activator can lead to Proclination of lower incisors which is the major cause of relapse after treatment, this can be prevented by: a-Acrylic capping cover at least 1/3 of labial surface of lower incisors b-Lingual relief behind the lower incisors With my best wishes:--------- Anchorage in Orthodontics Anchorage in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby