EXPANSIONEXPANSION
INDIAN DENTAL ACADEMY
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Topics :-
Classification
History Of Expansion
Arch Width Changes (Physiologic)
Anatomy Of Maxilla and Mandible
Histology Of Suture and Symphysis
Stresses generated during Transverse Expansionwww.indiandentalacademy.com
Expansion
Transverse Antero-posterior
DentalSkeletalwww.indiandentalacademy.com
ANATOMY ANDHISTOLOGY
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Symphysis joint(Grays Anatomy)
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Symphysis joint
Symphysis menti
(Atlas Oral AnatomyHolland G R)
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Symphysis joint(Grays Anatomy)www.indiandentalacademy.com
Bone
Fibrocartilage
Collagen Fibres
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Maxilla and its Articulations(Grays Anatomy)
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American Journal Of Dentofacial Orthopedics 1987;91)www.indiandentalacademy.com
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Midpalatal suture
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Zone Of Intense Proliferationwww.indiandentalacademy.com
A-P Direction Of Collagen Fibreswww.indiandentalacademy.com
Transversely oriented collagen fibreswww.indiandentalacademy.com
Network Of Collagen Fibres In centre Of Suturewww.indiandentalacademy.com
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s
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Sharpey fibres
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T
BS
TRANSITIONAL SPACEwww.indiandentalacademy.com
SINUOUS AND IMBRICATING NATURE OF SUTUREwww.indiandentalacademy.com
NARROWED ZONE OF CELLULAR PROLIFERATIONwww.indiandentalacademy.com
S
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LIGHT MICROSCOPIC VIEWwww.indiandentalacademy.com
ELECTRON MICROSCOPIC VIEWwww.indiandentalacademy.com
HISTORY(The Angle Orthodontist1999;69)(Rapid Maxillary Expansion;Timms)
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Sir Emerson C Angellwww.indiandentalacademy.com
San Francisco Medical Press 1860
*14 year old girl patient with ectopic left upper lateral and premolar.
*Importance of first permanent molars.
Dental Cosmos
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Expansion appliance:-Dr Angell
Note Diastema
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Appliance with contrarotating screw
Gold
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We must beg leave to differ with the author inthe conclusion arrived at,that by the use of apparatus described he succeeded in separating the superior maxilla from each other.With no disposition to assert that such a thing is utterly impossible,yet,when taking into consideration theanatomical relations existing between the two halves of maxilla and other bones with which they articulatesuch a result appears exceedingly doubtful.
(J.DeH.White)
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As shown in Dental Cosmos
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ARCH WIDTH CHANGES(American journal Of Dentofacial Orthopedics1997;111)(T.M.Graber;Orthodontics –Practise and Principles)
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Study Of Stress Distribution and Displacement Of Various Craniofacial Structures Following Application Of Transverse Orthopedic Forces:-
FEM Study
(The Angle Orthodontist2002;73)(American Journal Of Dentofacial Orthopedics 1987;91)
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Conclusions:-
•Maximum lateral displacement was 5.313mm at node 12911.
•Pyramidal displacement of the maxilla was visible from the front view.
•The width Of the nasal cavity increased markedly.The inferior parts of the pterygoid plates were markedly displaced or bent laterally,but minimal displacement was observed in the region close to cranial base.
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•Maximum negative Y-displacement(backward displacement)was 1.1599 at node 2314 corresponding to the posterior rim of the frontalprocess of the zygomatic bone.
•Maximum positive Y-displacement(forward displacement) was 1.077 at node6022,which represents the anteroinferior border of the nasal septum.
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•Maximum negative Z displacement(downwarddisplacement was 1.22 at node52,which represents theposterior most portion of the nasal septum.
•Maximum positive Z displacement(upward displacement)1.758mm at node241 which represents body of the zygomatic bone.
•Thus the nasomaxillary complex rotated such that the lateral structures had moved upwards and midline structures downwards.
•The anterior part of maxillary bone(point A)were displaced downwards.
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Topics:
Rapid Palatal Expansion
Slow Palatal Expansion
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Expansion
Skeletal Dental
Transverse Anteroposterior
SlowSemi rapidRapidUltra rapid
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Indications Of Rapid Palatal Expansion:-
Occlusion -Full cusp crossbite with skeletal component. -Some degree of dental as well as skeletal component. -No open bite tendency. -No preexisting dental expansion.
Respiration -Poor nasal airway -Septal deformity -Recurrent nasal ,sinus infection -Asthama
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Hazards Of RME:-
Oral Hygiene
Dislodgment and breakage
Tissue damage
Infection(Acute ulcerative gingivitis)
Failure of suture to open
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(a) Derichsweiler type Tags are welded and soldered to the palatal aspects of the bands to provide attachments for the acrylic which is also extended to the palatal aspects of all non banded teeth except the insicors.‑
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(b) Haas type A length of .045 in (1 .15 mm) stainless steel wire is welded and soldered along the palatal aspects of the bands The free ends are turned backand embedded into the acrylic base.A proprietary srew is set in the midline of the acrylic split.
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Haaswww.indiandentalacademy.com
(c) lsaacson type This appliance uses a special spring loaded screw called a Minne. Expander which is adapted and soldered direct to the bands without the use of acrylic, The screw may be reduced in length to suit narrow arches by shortening the spring, tube and rod.
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(d)Biedermann type This appliance also required a special screw, either Hyrax (Dentaurum 602 813). Leone 620 or Unitek ‑440 160, These have extensions in heavy gauge wire ‑which are welded and soldered to the palatal aspects of the bands
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Hyrax Screw
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Forestadent Screw
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Activation:-180º rotation /day(Ziebe)
Upto Age 15 years -90º both morning and evening.
Age 15-20 years -45º turns 4 times a day
Age over 20 years - Same as above or 45º in the morning and 90º at night
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In general,bony spicules appear at the age of 15 and 19 years(0.9% fo suture length),but these bridges may be removed by osteoclast to suit physiologic requirements.
A greater degree of obliteration occurs posteriorlythan anteriorly.
On average 5% of suture is closed by age 25.
(By Persson et al 1977)
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Age and prognosis:
Age 7 to 15:Good
Age 15 to 20:Good although recall every other dayTo check opening of suture.
Age 20 to 30:Possible but daily recall necessary,Danger that the suture does not open and there is overloading of the posterior segment,ulceration of mucosa.
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Treatment timing for rapid maxillary expansion(Angle orthodontist;2001)
The group treated before the pubertal peak,in the long term,showed significantly greater maxillary skeletalWidth,maxillary intermolar width,lateronasal width andLateroorbital width
The late treated group exhibited significant increase in Maxillary and mandibular intermolar width.(thus moreDentoalveolar than skeletal)
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According to Mayoral and Aristeguinta
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Slow Expansion Rapid Expansionwww.indiandentalacademy.com
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Maxillary Expansion by Hass(AJO;Vol 57,No8,1970)
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Maxillary Expansion by Hass(AJO;Vol 57,No8,1970)
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*Correction of mouth breathing.*Improvement of concentration.*Mouthbreathing not influenced.*Some improvement of nasal breathing www.indiandentalacademy.com
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Slow Expansion
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Schwarz Appliancewww.indiandentalacademy.com
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Crozat Appliance
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Fan Appliancewww.indiandentalacademy.com
Wipla-type Forestadent screw
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Bar type-Two way expansion screw
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The Nardella eccentric expansion screw
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Quad Helix
Ricketts
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3 D Multiaction palatal appliance
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3D Quad Helix palatal Appliance(Wilson)
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Sagittal I Appliance
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Sagittal II Appliancewww.indiandentalacademy.com
Ultra-Rapid Expansion
•By Chaure….3mm of expansion was achieved in one and half hour.
•Three visits.
•Anaesthesia is administered.
•Used by E.N.T. surgeons then.
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NiTi GROUP RPE GROUP
Measurement
Mean Standard Deviation
Mean Standard Deviation
PWC(mm)
0.99 0.45 1.41 1.09
IMWC(mm)
6.26 1.65 4.76 1.55
RATIO PWC/IMWC
0.16 0.08 0.28 0.17
PWC=palatal width change; IMWC=intermolar width change; PDC=palatal depth change; AT=alveolar tipping; MR=molar rotation; MT=molar tipping
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RATIO PWC/IMWC
0.16 0.08 0.28 0.17
AT(degrees)
6.61 3.73 5.08 5.43
PDC(mm)
-0.04 0.70 -0.07 0.89
MR(degrees)
26.61 16.29 1.58 2.74
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MR(degrees)
26.61 16.29 1.58 2.74
MT(degrees)
11.69 10.47 6.08 6.25
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The NiTi transpalatal loops has a transition temperature of 94oF. The martensitic transformation and superelastic properties of the NiTi wires helped the insertion of the expander into the lingual sheaths of prefitted maxillary molar bands. Expansion occurs after insertion when the appliance was warmed up to body temperature and the NiTi loops return to its original shape. Over expansion was built into the treatment to anticipate relapse (approximately 30%) due to uprighting of the maxillary molars after removal of appliance.
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NiTi transpalatal loops were sprayed with tetrafluoroethane refrigerant prior to placement of the appliance.
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Original Pendulum design
.032” TMA
NanceButtonOcclusal
rests
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Pendexwww.indiandentalacademy.com
T-Rex Design
Mesial wire
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The PHD Appliance
Pendulum Hygiene Design/devicewww.indiandentalacademy.com
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Thank youFor more details please visit
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