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Expansion in orthodontics /certified fixed orthodontic courses by Indian dental academy


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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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Expansion in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. Expansion In Orthodontics
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education
  3. 3. Introduction Expansion in arch has been one of the oldest means of creating space in the dental arches. It is also one of the conservative method of gaining space. It can also be used to correct the intermaxillary and dental arch relationships primarily in transverse direction. It enables correction of crossbites early in treatment.
  4. 4. History • Narrow maxilla was recognized for thousand years and Hippocrates has also refered to it. • In 1860 Emerson C.Angell placed a screw between maxillary premolar of a girl aged 14 yrs and wider her arch in two weeks. • In 1877 Walter coffin demonstrated the expansion of the maxillary arch using spring which caused separation of the mid palatal suture in children. • Pfaff, in 1929 described improved nasal function after maxillary expansion. • Haas, in 1960 reported increased nasal width,gain in arch and lowering of mandible with bite opening.
  5. 5. Rapid maxillary appliances Indications •Marked narrowing of the arches •Unilateral or bilateral cross bite •Mandibular prognathism with reduced anterior development of the maxillary base •Steep palate with septal deviation and mouth breathing due to enlarged adenoids •Cleft lip and palate •Mild arch length to tooth material deficiency.(1mm of expansion in post = 0.7 mm increase in arch perimeter)
  6. 6. Contraindications • No true contraindications • Anterior open bite cases • High FMA, convex profile cases • Skeletal asymmetry of maxilla and mandible with severe anteroposterior discrepancy. • Older age group due to ossification of sutures • Patients on dilantin therapy
  7. 7. Appliance design • • • • Rigidity Tooth utilization maximum Economy Hygiene Rapid maxillary expansion appliances • Banded appliances - Derischweiler type - Haas type - Beiderman type - Issacson type - Arnold type
  8. 8. • Bonded RME appliance • Full coverage bonded RME appliance • Removable RME appliance • Hilger’s palatal expander
  9. 9. Banded appliances Derischweiler type: •Tags are soldered to the palatal aspects of bands to provide attachments for the acrylic. •Acrylic also extends to the palatal of all non banded teeth except incisors
  10. 10. Haas type: • A length of the wire is soldered along the palatal aspects of the bands. • Free ends turned back and embedded in acrylic. • A screw is incorporated. • Banding difficult on malposed teeth. • Banding and cementation difficult on deciduous teeth. Indication • In late mixed and early permanent dentitions.
  11. 11. Beiderman type • This design also called hygienic palatal expander. • Requires a special screw. • These have extensions in heavy gauge wire which are soldered to the palatal aspects of bands. • Acrylic free palate, so no food entrapment, mucosal irritation and no ulceration. Indication Deciduous and early mixed dentition.
  12. 12. Issacson type •This appliance has a special spring loaded screw called a minne expander •It is soldered directly to the bands •No acrylic is used •Easy to fabricate
  13. 13. Arnold appliance • Coil spring expander is attached by means of vertical half tubes on the molar bands. • Tubes cosist of coil springs • It expands the arch by lingual pressures,using coil springs for power
  14. 14. Bonded appliance • Raymond Howe in 1982 developed this appliance • Clears the palate from acrylic • No banding needed- can be used on malposed teeth where parallel path of insertion is not possible • Less error prone as bands don’t have to be placed in impression • Easy to make on deciduous teeth. Wire framework Completed appliance On model Acrylic-lined bondable RME appliance
  15. 15. Full coverage bonded RME appliance • Developed by John Spolyar in 1984 • Solely for tooth borne anchorage • Spider type expansion screw is placed as anteriorly as possible • Acrylic free palate • No bands present • Difficult to remove Appliance showing Anatomy surface Extent of occlusal coverage Appliance on Study model
  16. 16. Removable RPE appliance • Developed by Vel Ivanovski in 1985 • Used for correction of crossbite and expansion of both maxilla and mandible • No bands, clasps and easy to fabricate • 2 mm thick acrylic sheet are moulded on the models with screw stabilized on the models using biostar • In a single appliance extension are given to the lingual of mandibular teeth for simultaneous expansion • Separate upper and lower appliances can also be made
  17. 17. Hilgers palatal expander •Consist of two molar bands with soldered horiontal helices and an acrylic plate •With embedded jackscrew •Anterior extension of the wire serve as the bonded occlusal rest •Helicles serve to rotate and distalize the upper molar •Jack screw produces orthopedic midpalatal disjunction
  18. 18. Activation • Use head gear plier to twist the molar bands distally to incorporate twice the the amount of rotation needed • Place the lingual bend in the vertical portion of the wire that extends out of the acrylic. • Hold the helical with the head gear plier and bend the appliance towards palate to place a minor tip back force on the molars Advantages • The appliance is able to make changes in arch width and form • Distal rotation of upper molars • Creates room for canine eruption • Anchors the molars during upper retraction
  19. 19. • Regime of screw rotation Zeibe in 1930 : 180 degree rotations per day Upto age of 15 years : the turn 180 degree is given as 90 degree in the morning and 90 degree in the evening. 15-20 years : overall rotation of 180 is possible by splitting the rotation into 4 turns of 45 degree each with approx equal time lapse between them. Age over 20 years : 45 degree turn in the morning and 45 in the night initially Over 25 years: surgical seperation may be required.
  20. 20. Zimring and Isaacson in 1965 : • Young or growing patients: two turns each day for the first 4-5 days and one turn each day for remainder of rme treatment. • Adult patients: two turns each day for the first two days and one turn each day for the next 5-7 days and one turn eac other day for the remainder of the rme treatment.
  21. 21. Effects of RPE • The separation of midpalatal suture is triangular in all three planes. • The fulcrum of separation lies at varying distance from MPS depending on age. • There is generally downward and forward movement of maxilla due to zygomatic buttressing. vertical sagittal
  22. 22. • The mandible also rotates downward and backward exaggerating retrognathia. • The alveolar bone bends laterally and the palatine bones inferiorly increasing nasal cavity. • Splaying of hamular processes of the sphenoid bone is seen. • As the maxilla moves forward and downward due to loosening of the circummaxillary sutures, maxillary protraction may be applied with face mask or reverse headgear. • Arch perimeter increase is 0.7 times the intermolar width increase. • Palatal depth is increased due to overeruption of posterior teeth. • Mandibular arch length expansion is also seen in RPE: upto 1.1mm increase in intercanine width and 2.5mm in intermolar width.
  23. 23. Clinical management of RPE patient • Pain is not usually present in juveniles, adults may complain. • Pain is usually at the time of activation. • Midline diastema is most important proof of separation. • Petechie may be present on the palatal mucosa which resolves in a week or two. • Occlusal interference are seen. • Patient report inability to masticate from back teeth. • Overexpansion is advised till lingual cusps of upper molars occlude with lingual inclines of lower buccal cusps.
  24. 24. Rapid expansion Slow expansion Both skeletal and dental changes seen from beginning (1:1) Both removable and fixed appliances can be used Force levels: 2-4 lbs Activation: 1mm /week Predominantly skeletal changes initially (8:2) .later dental changes take place with skeletal relapse Only fixed appliances can be used Force levels: 10-20 lbs Activation: .5-1 mm / day
  25. 25. Slow palatal expansion Appliances used Fixed • W arch • Quad helix • Ni-Ti arch wires Removable • Coffin spring • Expansion screws • Functional appliances
  26. 26. W- arch •A fixed type modification of coffin spring •First used by ricketts in cleft palate cases •Prefered in deciduous and mixed dentition where mild to moderate expansion is required Activation • Can be opened anteriorly at the curve as well as at the posterior apices •Opened 3-4 mm wider that passive width •Expansion done at the rate of 2 mm per month •Unequal arm length can be kept in true unilateral crossbite cases •Over treatment is done •Can be kept as a for 3-4 months
  27. 27. Quad helix Introduced by dr. Robert Ricketts in 1975 Indications: •All cross bites needing upper arch expansion •Crowding cases needing mild expansion •Class II needing molar distal rotation •Class III with constricted maxillary arch •Tongue thrusting cases •Cleft lip and cleft palate cases
  28. 28. Activation • A six week interval is observed before further activation Extra oral: • 1mm each side in molar region and 1.5mm anteriorly • Ricketts prescribes 500 gm of force to separate mps Intraoral: • Triple beak plier is used • Anterior bridge is bend by keeping single beak anteriorly for intermolar expansion • 2nd and 3rd bend on palatal bridges for lateral arms.
  29. 29. Modifications of quad helix Ricketts 3 in 1 Anterior and posterior expansion Molar rotation Tongue spurs
  30. 30. Ni Ti palatal expanders • • • • • • • • • Introduced by wendell arndt in 1993 A fixed – removable appliance Depends on shape memory and super elasticity of NiTi Transition temperature 94°F Continuous force levels between 230gms to 300 gms. Available in 8 intermolar widths; 26-47 mm 26-32mm width appliances are of softer wires for younger patients Freeze gel packs can be used to make appliance flexible for insertion
  31. 31. Coffin spring •Constructed from 1.25mm wire . •Two types can be prepared i.e. Tear shaped Diamond • Tags are prepared at the end of the wire to be embedded in the acrylic. • It is kept 1 mm away from the palate. • It is cheaper and less bulky but unless precise construction and adjustment these may be rather unstable.
  32. 32. Indications • Upper arch expansion where lateral expansion is indicated. • It can be used in cases of unilateral as well as bilateral crossbites. • Antero-posterior expansion required. Differential expansion in anterior or posterior region is desired. • Controlled movement can be obtained. • When space requirement is less than 3 mm.
  33. 33. Activation : • Pits are drilled into the base plates allow the initial width of the appliance to be checked with calipers .the spring is expanded anteriorly first, then posteriorly by pulling it apart, care being taken not to twist the appliance. • This easier and quicker to adjust than with pliers as it tends to distort the appliance. • An expansion of 2-3 mm will generally be appropriate.
  34. 34. Expansion screw •The expansion screw is a very small metallic appliance which may be designed to move a single tooth or a group of teeth or the skeletal bases as required. This screw as a source of force together with the acrylic segment of the plate effect the teeth and the alveolar process. •Different type of screws may be used advantageously for certain procedure during treatment with removable appliance .
  35. 35. • The screw normally transmits its forces by means of acrylic, which comes in contact with the teeth. • The patient usually activates the screw once or twice a week. • Fairly high force is generated but it is intermittent in nature. • Desirable features in screw are stability and minimal bulk. • Screws can be used for various tooth movements in antero-posterior and transverse arch expansion and also in contracting a wide arch.
  36. 36. According to desired action of screw •Expansion screw appliance used for symmetrical expansion of dental arch. •Appliance with screw to move individual teeth or small group of teeth in a buccal or labial direction . •Appliance with screw to move individual teeth or small group of teeth in a mesial or distal direction
  37. 37. Guidelines for screw positioning•It is positioned in three dimensions accurately. •It should be placed in the mid line oriented to median raphe when bi-lateral expansion is to be planned.Screw lies on a imaginary line passing between the first and second premolar. • In a narrow arch it should be positioned more posteriorly •The horizontal plane of the screw is placed parallel to the plane of the occlusal surface.
  38. 38. Activation • In children when expanding 90*turn at each adjustment is sufficient and adjustment is made twice a week. • In adults tooth movement has to be carried out more slowly so a 45* turn or1/4th turn per week is sufficient . Advantages •Controlled movement can be achieved. •Activation can be done at home. •Various types of tooth movement possible. •. It is easily available commercially do not require skill of the clinician •Can be added to suffix the fuctional appliances
  39. 39. Disadvantages •Reliance on the patient for the activation. •May cause difficulty in cleaning. •Does not applies a constant force. •Requires excellent retention . •Over- activation may cause problem.
  40. 40. Lower Schwarz Appliance • This is specific type of active plate used in early stages of the mixed dentition period, to produce orthodontic tooth movement in the mandible mainly uprighting the posterior dentition and increasing anterior arch length anteriorly •Schwarz appliance may be useful in patients with mild to moderate lower incisor crowding but will not satisfy the arch length requirements of a patient with severely crowded incisor region.
  41. 41. Parts of Schwarz plate • This is made from wire and acrylic • Simple ball end clasps are placed in the embrasures between the lower deciduous molars and lower first molars. • Adams can be used for additional retention usually not required. • Expansion screw is located in the midline and embedded almost in acrylic. • Additional acrylic also can be placed on the occlusal surface of the posterior teeth in case in which a posterior bite block effect is desired.
  42. 42. Advantages • It is easily manageable clinically. Usually delivered without adjustment. • Appliance is worn full time for first 3-5 month as an active plate ( one mm expansion each month can be expected.) and then as passive appliance for additional period of time for retention. • Additional arch length of 3-4mm(mcnamara) can be gained on routine basis . • Simple and a straight forward technique. Disadvantages • Not recommended in the treatment of gross tooth size/arch length discrepancy problem.
  43. 43. Y-plate expansion appliance • It is an active removable type of appliance which is similar to that of the bite plate and it is anchored on the maxillary arch with Adams clasps. • The labial bow inserts into the acrylic in the lateral incisor – canine embrasure • The plate has two jack screws that exerts a distalizing force. •The opening of the jackscrews exerts a distalizing component on the buccal segment teeth and a reciprocal force is delivered to the anterior palatal contour and maxillary incisors. •To reduce the mesial force component, which tend to tip the incisor labialy and dislodge the appliance, the screws are activated alternately and unilaterally
  44. 44. INDICATION: • First premolars erupted, giving increased anchorage. • Upright incisors. • No extensively bodily movement are required. • The second premolar have not yet erupted.
  45. 45. Functional appliances This expansion is not produced through the application of extrinsic bio-mechanical but rather than by intrinsic forces in the dental arch such as those produced by the tongue. (passive expansion) When the forces of the buccal and labial musculature are shielded from the occlusion, a widening of the dental arches often occurs.
  46. 46. Balters in this context states :“ It is unnecessary to use active forces for arch expansion as interplay of muscle takes care of dental arch formation, it should be realized that the orthodontics should lead to jaw orthopaedics i.e.. reforming the jaw and the dental arches on a functional basis. ”
  47. 47. Bionator • Originally developed by Balters in early 1950 . • Buccinators loops eliminates the tension of the strong buccinator muscle thus there is marked arch expansion . • Coffin spring is not active but stimulator for the tongue function
  48. 48. Frankel appliance • Frankel has emphasized on the use of labial and buccal vestibule. • Using lip pads and the buccal shield effectively hold the buccal and labial musculature away from the teeth and investing tissue eliminating any restrictive influence that this functional matrix might have.
  49. 49. • He has stated that the vestibular shields should be extended into the vestibular reflex so that the tension produced on the soft tissue and this pull on the soft tissue is transferred to the periosteum and results in deposition of new bone on the facial aspect of the alveolus.
  50. 50. – As for expansion it has tested the deep waters of time to be completely trusted and accepted as a respected treatment modality in the field of orthodontics.
  51. 51. Thank You Leader in continuing dental education