Rotation in Orthodontics

1. 1 Rotation Rotation in in orthodontics orthodontics Prepared by: Prepared by: Dr. Mohammed Alruby Dr. Mohammed Alruby R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

2. 2 Definition Types of rotation Etiology of rotation Winging and counter winging rotation Advantages of derotation Biomechanics of rotation correction Methods of correction rotation Management of molar derotation Retention of rotated tooth Methods to prevent relapse Active retention R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

3. 3 Definition: Observable mesio-lingual or disto-lingual intra-alveolar displacement of the teeth around its longitudinal axis Types: 1-Centric rotation: only rotation around the long axis in which the angulation of the long axis of the tooth is unaltered 2-Eccentric rotation with tipping of the tooth If the body rotates about its center of resistance, it is called pure rotation Types: Mesio-lingual, disto-lingual, mesio-labial, disto-labial Possible etiology of rotation: -Severe crowding -Supernumerary tooth or odontoma -Typical class II div 2 malocclusion where upper central lingually inclined, leaving insufficient space in dental arch -Unilateral cleft where usually teeth lateral to cleft is rotated -Over retained deciduous tooth -Ectopic canine -Unerupted teeth at base of root of the completely erupted teeth -Scare tissue from trauma -Spacing different type of force acting on the teeth such as: masticatory force, force from the tongue, lip biting, thumb sucking Winging and counter winging: Dehlberg, stated that: if the distal margins of the central incisors are rotated in labial direction -------- winning if the distal margin of central incisors are rotated in lingual direction ----------- counter winning the most common rotated teeth are L5 followed by L4 and U1 with the same prevalence R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

4. 4 advantages of de-rotation: 1-Rotated posterior teeth occupy more space than normally placed teeth, derotation of these teeth provide some amount of arch length 2-Absence of rotation is one of the keys to normal occlusion 3-Non rotated teeth have tight contact with its adjacent teeth 4-Derotation is essential for proper maxilla to mandible relation and proper intercuspation 5-Derotation is essential for equal distribution of occlusal forces N: B: Force required for derotation is 30 – 60gm or 60 – 100gm depending from case to case Optimum force similar to tipping force Alignment of rotated anterior teeth Broader mesiodistally Occupy less space when they are rotated Alignment of such teeth require space For every millimeter of rotation required the same amount of space required for aligning of teeth Biomechanics for rotation correction: Rotation can achieve by two ways: 1-Using couple of force 2-Using single force and slop Couple of force: two parallel forces equal in magnitude but in opposite direction separated by distance that act upon a tooth are required This is the only force system couple of producing pure rotation of body around its center of resistance and the longitudinal axis of the tooth from occlusal view In this case, the tooth maintains its position because both forces act at the same distances perpendicular to the center of resistance leaving only pure moment to occur (pure rotation) N: B: When crowded and rotated maxillary incisors are corrected orthodontically in adults, there is a black triangle left after correction specially if sever crowding was present For that reason: black triangle must be noted and prepared patient during examinations for reshaping of the teeth to minimize this esthetic problem Alignment of rotated posterior teeth Broader labio-lingually Occupy more space when they are rotated Alignment of such teeth creates space Space created depend on the tooth (molar , premolar and amount of rotation present R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

5. 5 Methods for correction of rotation in orthodontic appliances 1-Ligation: To achieve orthodontic tooth movement, arch wires must be tied to the bracket slot by metal or plastic ligation The traditional elastics O ties often failed to correct severe rotation because of inability to fully seat the arch wire into bracket slot a-Double over tie (figure 8): In which the o –ring criss - crosses over the bracket Twist the o – ring in this manner increases its elastic tension which help seat the arch wire b-Modified figure 8 ties: The force level of the o – rings are symmetrical they may still be in adequate to fully seat the wire This modification creates a symmetrical force to help fully seat the arch into the bracket slot c-Anti-rotational ties: d-Double ligation: In which the wire is ligated firstly the bracket under the wire and then over the same wire R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

6. 6 e-Single tie (isolated tie): Firm ties are made to the bracket farther from the arch wire, use of finger or an instrument to press the arch wire as flush as possible against the bracket to be filled an elastomeric ligature or rotation wedge or even left empty f-Modified rotation tie: Rotation tie was modified by using elastic modules or elastic chain with steel ligature wire, the chain is attached to the prominent side of bracket passes inter-proximally then ligature wire is attached to main arch wire on other side g-Circumferential tie: Similar to modified rotation tie but is done with stst ligature wire. In case of posterior teeth and canine, small retention area can be molded with composite resin or an auxiliary can be placed or soldered onto the lingual palatine surface to prevent displacement of the ligature wire N: B: Anti-rotational tying of the canine during canine retraction or the 1st premolar in case where the 2nd premolar have been extracted is a useful way of preventing such rotation In cases of the wings of the dental bracket alone should be tied to prevent it from moving away from the arch wire during retraction During the tying procedure the tip of clinical probe is inserted between the bracket and ligation threads allowing slight amount of slack to ensure freedom of movement to reduce friction ALSO: anti-rotational tying of teeth neighboring to open coil to guard against rotation R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

7. 7 2-Auxiliaries: a-Rotational wedge: It acts as fulcrum between the wire and bracket, it is ligated to the tie wing of the bracket closest to the wire available in different color b-Steiner ligature rotation wedge: Round elastomeric wedge easily attaches to the bracket under the arch wire, supplied on perforated ligature wire c-Button: Can be used to produce a couple of force by bonding buttons to buccal and palatal surface of the rotated tooth and use elastic chain between them and the neighboring teeth or anchorage devices d-Monkey hook: S shaped auxiliary with an open loop on each end for the attachment of intra-oral elastics or elastomeric chain R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

8. 8 e-Double loop derotation: In case of severe rotation, it is very difficult to bond attachment for proper of couple force due to inaccessibility to surface or area of attachment In such case multiple repositioning of bonded attachment will be required during derotation f-Rotating spring: = Provide simple and effective means of de-rotating teeth without the removal of arch wire, = used for Begg and Tip Edge brackets = can do clockwise or anticlockwise movement = not effective in de-rotating posterior teeth = exert light continuous force that can align rotated tooth within several weeks 3-Derotation with NiTi wire: In the pre-adjusted edgewise system, use highly resilient super-elastic NiTi wire for initial alignment and final engagement of rectangular wire in brackets and rotated teeth Disadvantage: can cause undesirable force for neighboring tooth lead to unwanted movement 4-Sectional technique: De-rotation of upper incisors with sectional 0.018 Niti and diastema closure with partial derotation and finally placed 0.017 x 0.025 stst wire Complete derotation was achieved after 10 weeks and then start retention phase R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

9. 9 5-2 x 4 appliance: Band cemented or bond on both upper 1st permanent molars and bracket bonded onto the upper incisors, by sequence of wires the correction of rotation may occur through several weeks and then start retention phase 6-Piggy back technique: Main arch wire with open coil to open adequate space to permit the rotation correction, the piggy back wire was fully engaged into the rotated nonaligned teeth / tooth and then ligated to the main arch with the adjacent teeth 7-Loops: a-Double vertical loop: It is contoured on either side of the tooth, when tied into the bracket of the rotated tooth, the loop of one side of the tooth will be displaced lingually and the loop on the other side will be displaced labially causing a reciprocal rotation actually on the bracket b-Box loop: Composed of series of vertical and horizontal levers contoured in such manner to provide a short section of arch wire that is freely movable in all planes of space and usually is contoured to the width of a single tooth 8-Anghileri appliance (ANG): = Invented by Dr. Matias Anghileri from Argantena = Place the initial arch wire and bond button on the buccal surface of rotated tooth = Insert a passive spring between the two teeth surround the rotated tooth = use ligature wire from the button to compress the spring approximately a third of its original length, an easy way to do this by placing the ligature through the 1st or second coil = the spring can exert its force in the same direction to which the tooth must be rotated = the spring works continuously to de-rotate the tooth without adjusting the ligature R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

10. 10 == the tooth where the spring is going to be anchored must have a greater anchorage than rotated one to avoid an unwanted rotation 9-Whip appliance: Introduced by Huston and Isaacson in 1980 Single rotated tooth in patient with otherwise acceptable occlusion acceptable occlusion may be rotated with Whip appliance where there is adequate space SINCE: Whip itself provide no labio- lingual control, labial bow should be adjusted to touch the labially placed surface of rotated tooth / teeth Components: a-Oval molar tube: (mandibular 1st molar tube): is bonded or banded directly to the labial surface of the rotated tooth / teeth Bonded edgewise bracket can also be used, but it can exert unnecessary torque during rotation b-Whip spring: is fabricated of 0.016 heat treated Australian wire = the recurved end of whip is inserted into the oval molar tube while the other end is formed into a hook to be engaged onto the labial bow This design is serve more in case of mesio-labial rotation of incisors Whip itself provides no labio-lingual control – labial bow should be adjusted to touch the labially placed surface of rotated tooth c-Removable appliance part: simple removable plates with adequate retention using Adams clasp and labial bow made up of thicker gauge stst wire (19 / 20) gauge. Advantages: 1. Offering a solution in the mixed dentition period, relatively in a short time 2. Providing increased vertical and horizontal anchorage due to palatal coverage 3. Anchorage control is less critical 4. Force system is relatively simple when this appliance is used 5. Management of oral hygiene is easier 6. Patient compliance is less critical, because when removing the appliance, the damage of mucosa by wire leads to patient discomfort 7. Whip appliance can be used in emergency situations in the mixed dentition, such as traumatic occlusion of central incisors. Clinical drawbacks: = Much attention should be considered not to activate Whip appliance in vertical plane otherwise unwanted mesio-distal crown and root movement may be produced extrusion and labial tipping of maxillary incisors might occur during treatment = Furthermore, Whip spring can wound the mucosa if not adjusted carefully = Debonding of bracket and distortion of the spring. However, these problems can be minimized through satisfactory compliance R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

11. 11 10-Hooked appliance: Removable appliance with hooks soldered or incorporated in acrylic, the rotated tooth is bonded or banded with attachment to correct the rotation with elastic or power chain between the attachment and hook 11-Removable appliance: Advantages: -Simplified and coast effective treatment for successful derotation of anterior teeth in mixed dentition -Reactive forces are less, so there is no particular problem with anchorage -Better maintenance oral hygiene Limitation: -Ideal case selection is required as it may be indicated early in the case of rotated maxillary central incisors -Probably correct early mixed rotation less than 45 degree -Has high risk of relapse and because patient compliance is needed -Need for accurate adjustment of the labial bow, palatal spring and acrylic baseplate 1-Double cantilever Z spring: Construction: -0.5mm hard round stst wire -2 helices of small internal diameter -Spring is positioned perpendicular to the palatal surface of the tooth with a long retentive arm (placed away from the tissue) 12mm in length Activation: -Only one helix may be activated to correct mild rotation Uses: -To correct of anterior teeth cross bite / rotation where the overlap is less than the freeway space. The spring is effective only when there is enough space for aligning R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

12. 12 2-Labial bow with vertical M loop: Function: Alignment of canine, if it is labially positioned, the M loop moves the tooth primarily in a lingual direction. Depending on the location of the counterpart of the loop, the tooth can be rotated = the loop should be only lie on the most prominent part of the crown avoiding contact with gingiva 3-Labial bow with retractive canine loop: Alignment of labially rotated canine To optimize the point of force application, the loop should embrace the tooth surface as far as possible This loop can tip the canine distally as well as lingually 12-Invisalign: Teeth with rotation may require a combination of attachment and elastics Correction of rotation with vertical rectangular attachment on the rotated teeth The location of attachment on the tooth can be changed during the course of treatment to ensure complete rotation correction Management of molar derotation Maxillary molars may be rotated as a result of premature loss of 2nd deciduous molars and mesial shifting of 1st molars which is usually accompanied by mesio-palatal rotation taking palatal root as a fulcrum for this movement Rotation of upper 1st molars may also occur as a minimum anchorage unit or due to poor appliance design and anchorage loss during treatment Rotation of upper 1st molars has deleterious sequel on occlusion and may complicate treatment due to encourage on the space requirement {rotated upper 1st molars occupy more space than normal), also may result in cusp to cusp or even class II occlusion R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

13. 13 Causes: 1-Premature loss of 2nd deciduous molars 2-Use of U6 as minimum anchorage 3-Poor appliance design 4-Anchorage loss during treatment Sequelae: 1-Occupy more space 2-Cusp to cusp relations 3-Class II occlusion Diagnosis: Clinical: According to McNamara 1993 for evaluation of U6 position: the buccal surface of U6 on both right and left sides should be parallel when viewed from the anterior area Cephalometry: lateral cephalometry: There are number of cephalometric methods that used to assess the anterior posterior position of U6: -U6 ---- to ----- NA line ------ 27 -+3 ------------------------------------- Steiner -U6 ---- to------ pt vertical ----- age of patient +3 -+3 ----------------- Rickett -U6 ---- to----- key ridge -U6 ---- to----- temporal curve of Sassoni ---------- pass through mesio-buccal root -U6 long axis to ---------- SN ------------------------ Sassoni -U6 long axis to ---------- pp -------------------------Sassoni -U6 long axis to --------- occlusal plane ------------Sassoni -U6 long axis to mandibular plane ----------------- Proffit In anterior posterior cephalometry: -Line tangent mesial surface of U6 -Line tangent mesial surface of L6 And measure space between these two lines: 2mm Cast: 1-Henry 1956: Measured the angle between median palatine raphe and line through cusps of U6 2-Friel 1959: Use median palatine raphe as a reference line angle between the raphe and line through mesio- buccal and mesio-palatal cusp of U6 3-Foresman 1964: -Measured angle between line passing through mesio-buccal cusp and disto-palatal cusp and median palatine raphe: 60 degree -Line passing through mesio-buccal cusp and mesio-palatal cusp to median palatine raphe each 3 degree rotation will be increase the width of space of 1st molar width by 0.25mm 4-Orton 1966: R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

14. 14 Measured angle between line tangent of buccal surface of U45 and line tangent buccal surface of U6 5-Rickets 1969: Describe line passing through the disto-buccal and mesio-palatal cusps of U6. If this line bisects the distal half of canine on the contra-lateral side so U6 is in correct position 6-Farahat 2012: T: ------------ cusp tip of maxillary permanent canine DB: ----------disto-buccal cusp tip of maxillary 1st permanent molar ML: ----------mesio-lingual cusp tip of maxillary 1st permanent molar Line a: ------line extended from disto-buccal cusp tip and mesio-lingual cusp tip of U6 right side and extended to opposite side of arch line b: -----line drawn through ditto-buccal cusp tip and mesio-lingual cusp tip of left side of U6 and extended to opposite side of arch line a1: ---- perpendicular line drawn from cusp tip of left canine to line a line b1: ----- perpendicular from cusp tip of right canine to line b - length of a1 and b1 is measured -Line a1 represent right side U6 rotation: --- 7.89mm - Line b1 represent left side U6 rotation: ---- 6.41mm N: B: In class II: a1: ---- 8.0mm b1: --- 6.2mm In class III: a1: ---- 8.3mm b1: ---10.16mm Methods for correcting molar rotation: 1-Toe in bends within successive arches 2-Transpalatal arch (Carlson and Hoeu) This method is especially favorable when the need for de-rotation is the same on both sides of the arch 3-Extra-oral force: bayonet bend is placed at the distal end of the intra-oral bow which acts as stop to direct the full force of headgear against U6 4-Denholz appliance: muscular anchorage system: an appliance is similar to lip bumper, it consists of : -Two molar bands with buccal tubes -Base arch of 0.036 inch stst to fit buccal tube -Vestibular screen -Coil spring are inserted into the base arch to dissipate the force of vestibular screen into U6 5-Sliding jigs together with class Ii elastics 6-Modified Nance with Quad helix 7-Nitinol coil spring 8-Jon’s Jig 9-Distalizing Jet R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

15. 15 Retention of rotated tooth Rotation are easy to treat but is very difficult to retention When the tooth is rotated around its long axis, the supra- alveolar tissue remains under tension SO rotation have very high risk of relapse due to elastic recoil of the stretched supra-alveolar and transeptal fibers Methods to prevent relapse of rotation: 1-Early correction of rotated teeth: It is advisable that all rotation to be corrected to labial or slightly over-corrected positions in the early stages of treatment The longer the rotated teeth are held in correct position, the greater the chance for stability Exp: the mesio-labial rotation of U2 in class II div 2 malocclusion should be slightly overcorrected because its relapse very easily 2-Circumferential supra-crestal fibrotomy CSF: Advocated for release of soft tissue tension and attachment of fibers after orthodontic correction of tooth rotation These procedures are done at the end of finishing phase of treatment before appliance removal and beginning of retention phase (supra-crestal fibers are sectioned and allowed to heal and orient while the teeth are held in the proper position) After supra-crestal fibrotomy, there is some dental mobility that is due to the incision of the transeptal fibers that bound the teeth with other teeth, this gradually diminishes in 2 -4 weeks Procedures: a-Edward technique: = under local anesthesia no 11 knife is passed through the gingival sulcus up to crest of alveolar bone = interproximal cuts were made on each side of the rotated tooth and along the labial and gingival margin = no need for periodontal pack = this surgery is not indicated for patient with crowding without rotation R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

16. 16 b-Papilla split: alternative to CSF: Procedure: Vertical cuts are made in the gingival papilla without separating the gingival margin and papilla tip Advantages: a-Reduce the possibility that the height of gingival attachment will be reduced after surgery, and it is particularly indicated for esthetically sensitive area b-Easier and perform with an orthodontic appliance and arch wire in place c-Form the point of view of improved stability after orthodontic treatment, the surgical procedure appears to be equivalent c-Bonded retainer: = Multistrand wire individually adjusted and bonded to each tooth in the desired arch segment for long term retention = Recommended removable plate to be used with bonded lingual retainer for severely rotated maxillary anterior teeth with different type of malocclusion = The labial wire of this acrylic plate extend distal to the bonded retainer to avoid the risk of retainer wire fracture = The acrylic of the plate can be ground away from the teeth involved in the bonded retainer Active retention: 1-Spring aligner: Use to maintain the anterior teeth aligned and / or to correct small rebounds Construction: Like the circumferential or wrap around retainer, but the main difference is that it only includes the six anterior teeth meanwhile the wrap around retainer includes all the erupted teeth R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby

17. 17 Place and take off technique: For the correction of rotated teeth, we must apply pink wax or block out over the aspect of the tooth in plaster that we want to rotate and on the contra-lateral aspect, we must wear off the model, in these cases we recommend to place fixed retainer 2-Essix retainer: esthetic retainer Retention is based on acetate or plastic plates R Rotation otation in Orthodontics in Orthodontics Dr. Mohammed Alruby Dr. Mohammed Alruby