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



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.

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.

Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call



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

  • INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  • Contents• Introduction • Modes of Expansion – Orthodontic expansion – Passive expansion – Orthopedic expansion • Orthopedic expansion – W –Arch, Quad helix – Schwarz appliance • Rapid Maxillary Expansion – Biological basis of Rapid Maxillary Expansion – Uses and contraindications of maxillary expansion – Biomechanics of Rapid Maxillary Expansion – Effects of Rapid Maxillary Expansion – Treatment timings www.indiandentalacademy.com
  • • Appliance design – Banded appliance • Haas appliance • Hyrax appliance • Minni expander – Bonded appliance – Butterfly expander – Fan shaped expander – Nickel palatal expander • Slow Maxillary Expansion • Semi Rapid Maxillary Expansion • Effects of Rapid Maxillary Expansion in skeletally mature patients • Surgically assisted rapid palatal expansion (SARPE). • Bone borne palatal expander • Conclusion • References www.indiandentalacademy.com
  • Introduction • Expansion of the maxillary arch to correct transverse skeletal and dental discrepancies and to reduce intra-arch crowding is an accepted method of treatment that was first outlined by Angel in 1860 and popularized by Haas 100 years later. • During this time various appliances were developed to create maxillary expansion ranging from the basic removable acrylic appliances with a midline screw to the banded or bonded expansion devices.www.indiandentalacademy.com
  • • The concept of rapid palatal expansion to attain skeletal widening of the maxilla was revisited by Goddard in the 1890s and by Landsberger in 1910, but the technique seemed to languish for the next 50 years until numerous studies confirmed the creation of skeletal rather than dental changes. www.indiandentalacademy.com
  • Modes of Expansion • Expansion of the dental arches can take place by – Orthodontic expansion – Passive expansion – Orthopedic expansion www.indiandentalacademy.com
  • Orthodontic Expansion • Orthodontic expansion is produced by conventional fixed appliances and by various removable expansion plate and finger spring appliances • It usually result in lateral movements of the buccal segments that primarily are dentoalveolar. www.indiandentalacademy.com
  • • A tendency exists toward a lateral tipping of the crowns of the involved teeth and a resultant lingual tipping of the roots. • The resistance of the cheek musculature and other soft tissue still remains, providing forces that may lead to a relapse or rebound of the achieved orthodontic expansion. www.indiandentalacademy.com
  • Passive expansion • When the forces of the buccal and labial musculature are shielded from the occlusion, as with the Frankel appliance, a widening of the dental arches often occurs. • Brieden et al, in an implant study conducted in patients treated with the FR- 2 appliance of Frankel, have demonstrated that bone deposition occurs primarily along the lateral aspect of the alveolus rather than at the mid palatal suture.www.indiandentalacademy.com
  • • During deglutition Anterior lip seal and Posterior oral seal creates a Negative atmospheric pressure within oral cavity • So the Cheeks are sucked into interocclusal space as mandible returns into postural rest position • This exerts an Constricting influence on the dentoalveolar process and prevention of eruption of buccal segments www.indiandentalacademy.com
  • • Thus Shields prevent the pressure of the buccinator on the dentoalveolar area during deglutition and at rest, inducing downward and outward movement of teeth and tissues. • A related type of spontaneous arch expansion also has been observed following lipbumper therapy. www.indiandentalacademy.com
  • Periosteal pull of Buccal shields: Shields and pads can be extended into the depth of vestibule Causing tension without creating irritation This produces a pull on the contiguous periosteal tissue of the maxillary bone leading to increased bone activity in contiguous osseous structure Maxillary basal bone is widened Alveolar shell over the erupting teeth proliferates laterally www.indiandentalacademy.com
  • • In a study conducted at Manipal & Davangere by P.P. Biswas , K.S. Shetty, A.Valiathan (JIOS 1993), 10 cases treated by the Frankel appliance were examined for changes in arch width post treatment. • All teeth except maxillary canine exhibited buccal bodily movement due to periosteal pull provoked by the vestibular shields. www.indiandentalacademy.com
  • The Lip Bumper •The lip bumper is useful particularly in patients who have tight or tense buccal and labial musculature. • It is made of heavy wire to prevent distortion. •The wire is adjusted to be 1.5 to 2mm facial to the lower incisors and the plastic shield is added to increase contact with the lip.
  • • The appliance usually is worn full time and may be ligated in place. • The lip bumper also would lie at the gingival margin of the lower central Incisors. • So it not only increases arch length through passive lateral and anterior expansion but also serves to upright the lower molars distally, adding to the available arch length increase. www.indiandentalacademy.com
  • Orthopedic Expansion • Three methods to cause maxillary expansion are – Split removable plate with jack screw – Lingual arch- a W- Arch or quad helix – Fixed palatal expander with a midline screw • In primary dentition and early mixed dentition less force is required to open the suture, so all three methods produce both dental and skeletal effects • Even in late mixed dentition, sutural expansion requires placing a relatively heavy force across the suture • This can be achieved by both slow and rapid maxillary expanders in late mixed dentitionwww.indiandentalacademy.com
  • • Split palate with jack screw – Although it is possible to expand maxilla in mixed dentition with a split palate type of removable appliance, there are two problems • This depends upon patient compliance for success • Appliance can be easily displaced – So this approach is less successful and less cost-effective than expansion lingual arch www.indiandentalacademy.com
  • The W-Arch • The W-Arch was originally used by Ricketts to treat cleft palate conditions • This is a fixed appliance constructed of 36 mil steel wire soldered to molar bands • This appliance is activated by opening the apices of W • The appliance delivers proper force levels when opened 4-5 mm wider than the passive width • It common for teeth and maxilla to move more on one side than the other, so precise bilateral expansion is the exception rather than the rule • But still acceptable correction and tooth position are almost always achieved www.indiandentalacademy.com
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  • The Quad helix • This is the more flexible version of W-Arch • In order to increase the range of force and produce more flexibility, total of four helical loops were incorporated in anterior and posterior segments creating a quad helix appliance • It is made of 0.038 inch round stainless steel or blue eligioy wire and soldered to bands that are cemented either to the permanent maxillary 1st molar or deciduous 2nd molars. www.indiandentalacademy.com
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  • Activation of Quad Helix • As a rough guide, it is expanded extraorally such that the bands of the quad helix lie half way past the molar crowns, before cementation. • Intraorally it is activated with a 3 prong plier at the anterior and posterior palatal bridges every other week. • Intraoral appliance adjustment may lead to unexpected changes, and so removal and recementation are recommended at each activation visit • The forces produced by the quad helix are in the range of 0.5 to 1.5 lbs( 200- 600g). These forces are well below those exerted by the Jackscrew expander. www.indiandentalacademy.com
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  • Modifications of Quad helix 1. It can be used in conjunction with a protraction facemask to advance the maxilla. 2. The anterior bar of the quad helix appliance may be modified to counter thumb sucking and tongue thrust habit or to control eruption of anteriors. 3. It may be also used to maintain space and to augment anchorage when required. www.indiandentalacademy.com
  • Schwarz appliance • This is a removable expansion plate that can be used in early stages of mixed dentition in the mandible • This appliance was mentioned over a hundred years ago by Kingsley • The appliance consists of simple ball clasp placed between the first and second deciduous molars and the permanent first molar • If additional retention is needed Adams clasp can be placed in permanent first molar • The expansion screw is placed in midline and almost entirely embedded In acrylicwww.indiandentalacademy.com
  • • The Schwarz appliance can be used in patients who have arch length deficiencies and/or posterior teeth that have an abnormal lingual inclination • It is rare that we could use Schwarz appliance as a sole appliance to produce orthodontic tooth movement, an exception is the treatment of patient with posterior buccal crossbite(scissors bite) • The gradual expansion of Schwarz appliance produced by activation of midline screw, simply tips the posterior teeth in a lateral direction • This is followed by Rapid Maxillary Expansion which would stabilize mandibular dentoalveolar position during the retention period www.indiandentalacademy.com
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  • Rapid maxillary expansion www.indiandentalacademy.com
  • Rapid Maxillary Expansion • Rapid maxillary expansion (RME) constitutes a routine clinical procedure in orthodontics, with its main purpose to normalize the constricted maxillary arch. • Forces of large magnitude delivered during activation of an expansion screw open the intermaxillary suture, increasing the basal bone width and the dental arch perimeter. • In addition to the desirable transverse altérations, RME produces perceptible changes in the sagittal and vertical facial planes.www.indiandentalacademy.com
  • Biologic basis of Rapid Maxillary Expansion • Upon the application of transverse biomechanical forces, initial changes involve the lateral tipping of the posterior maxillary teeth as the periodontal and palatal soft tissues are compressed and stretched. • This stage of orthodontic response appears to be essentially complete within a week. • Subsequent orthodontic movements will occur through bodily translation as the compressed buccal alveolar plate resorbs at the root- periodontal interface from continued force application. www.indiandentalacademy.com
  • • The theory was that with rapid force application to posterior teeth, there would be not enough time for tooth movement, the force would be transferred to the suture • If the applied transverse forces are of sufficient magnitude to overcome the bioelastic strength of sutural elements, orthopedic separation of the maxillary segments can occur. • The separation and repositioning of the palatal segments will continue until the force distribution is reduced below the tensile strength of the sutural elements. • Reorganization and remodeling of the sutural connective and skeletal tissues may then proceed in the stabilization of the expanded maxillary arch. www.indiandentalacademy.com
  • Uses of Maxillary expansion • Correction of crossbites – Most commonly recognized indication for maxillary expansion – It is very common for one or more of maxillary teeth to be in lingual orientation relative to mandibular dentition – Through widening of midpalatal suture the correction of posterior crossbite is accomplished • Addition of arch length – Expansion results in increase in total arch length which will allow accommodation of rotated, displaced or impacted teeth – Adkins and Nanda AJO 1990 reported that Rapid maxillary expansion yielded 0.7 mm increase in arch perimeter for every 1 mm increase in first premolar width www.indiandentalacademy.com
  • • Correction of axial inclination – Patients with maxillary constriction and subsequent dento-alveolar compensation show a buccally flared orientation of posterior teeth – Severe cases in which buccal root torque to correct its inclination might cause cortical plate perforation, can be corrected using maxillary expansion followed by fixed appliance to just tip the teeth rather than application of buccal root torque • Spontaneous correction of class II – Widening of maxilla in class II cases with maxillary constriction in mixed dentition often leads to spontaneous posturing forward of mandible during retention period www.indiandentalacademy.com
  • • Preparation for functional jaw orthopedics – Many cases being prepared for functional appliance require an initial phase of rapid maxillary expansion, to widen the maxilla and to correct tooth size and arch length discrepancies • Orthopedic correction of early class III – Even in patients whom maxillary expansion is not indicated, rapid maxillary expansion can be done to disrupt the circumaxillary sutural system to facilitate response of maxilla – The bonded rapid maxillary expansion is also used to anchor the orthopedic face mask to maxillary dentition www.indiandentalacademy.com
  • • Reduction in nasal resistance – Although not a predictable part, significant number of patients demonstrate reduction in nasal resistance following rapid maxillary expansion • Broadening the smile – Although there is little clinical research to support rapid maxillary expansion for esthetic purposes, it is expected to become increasingly common for patients with large buccal corridor spaces • Reduction in night time bed wetting or nocturnal enuresis • Improvement in hearing level of subjects with conductive hearing loss www.indiandentalacademy.com
  • Contraindications for RME • Uncooperative patients • Single tooth crossbites • Patients who have anterior pen bites and steep mandibular plane angles and convex profiles • Skeletal asymmetry of maxilla or mandible www.indiandentalacademy.com
  • Biomechanics of Rapid Maxillary Expansion Lee et al AJODO 1997 identified centre of resistance of dentomaxillary complex www.indiandentalacademy.com
  • Stanley Braun AJODO 2000 Frontal view Occlusal view www.indiandentalacademy.com
  • Frontal view Occlusal view www.indiandentalacademy.com
  • • If less tipping were desired (in the frontal view) and a more linear opening of the maxillary suture anteroposteriorly (in the occlusal view), the fabricated structure joining the sutural opening mechanism to the teeth would have to be more rigid, • By increasing the rigidity of both the sutural expansion device and the wires joining it to the teeth, the moment induced by the necessary offsets from the dentomaxillary centers of resistance are reduced, resulting in reduced equivalent moment- to-force ratios at the centers of resistance. www.indiandentalacademy.com
  • • This causes the center of rotation to migrate superiorly in the frontal view, reducing the degree of tipping, and in the occlusal view, the center of rotation would migrate further posteriorly, resulting in a more linear separation of the midpalatal suture. • Increased rigidity can be obtained by using the largest possible diameter stainless steel wires and a larger diameter activating screw. • The sutural expansion designs that use an acrylic interface with the teeth are far less stiff than those constructed solely of soldered stainless steel wire. www.indiandentalacademy.com
  • Effects of Rapid Maxillary Expansion • In a finite element study conducted to evaluate stress distribution along craniofacial sutures and displacement of various craniofacial structures with rapid maxillary expansion (RME) therapy, Pawan Gautam and Ashima Valiathan AJODO 2007 reported that the wedge-shaped opening was produced both anteroposteriorly and superoinferiorly • Separations were pyramidal, with the base of the pyramid located at the oral side in the vertical plane and anteriorly along the anteroposterior plane. www.indiandentalacademy.com
  • • The reason for the wedge-shaped opening in the anteroposterior plane is the pterygomaxillary connection that binds the sphenoid bone to the maxillary bones. • The entire maxilla moved anteriorly and downwards in response to RME • This is probably due to the disposition of the maxillocranial sutures. • Sicher claimed that these sutures are oriented so that growth would produce a downward and forward force vector of maxillary movement. • The maxilla rotated in a clockwise direction with ANS showing more downward displacement than PNS. www.indiandentalacademy.com
  • • Garib et al AO 2007 evaluated the long-term effects of rapid maxillary expansion (RME) via banded expanders in the sagittal and vertical facial planes. • The findings of this study revealed that the maxillary sagittal position remained unchanged in relation to the cranial base, considering the slight changes in SNA angle in the RME group, also ANB and bony profile convexity (NAP) were reduced in both the groups • There were no statistically significant differences between the study groups in changes observed for upper anterior and posterior facial heights (UAFH and UPFH) www.indiandentalacademy.com
  • • Thus, the alterations that occur immediately after expansion and are frequently reported in the literature, such as increases in facial convexity and overjet, should be considered ephemeral phenomena. • These results do not provide a basis to contraindicate RME in patients with a convex profile based on the side effects observed soon after expansion. • Also even though RME causes vertical maxillary displacement, as demonstrated by several studies, this vertical alteration is not significant in the long term www.indiandentalacademy.com
  • Pterygoid plates • Both the lateral and the medial pterygoid plates were displaced laterally • The inferior portions of the medial and lateral pterygoid plates were displaced more compared with the superior portions. • This can be explained by the fact that the pterygoid plates are more resistant to bending in the parts closer to the cranial base where the plates are much more rigid. www.indiandentalacademy.com
  • • The main resistance to the midpalatal suture opening is probably not in the suture itself; rather, it is in the surrounding structures with which the maxilla articulates, particularly the sphenoid and the zygomatic bones • The pterygoid plates of the sphenoid are connected to the horizontal plate of the palatine bones through the pyramidal process of the palatine bones. • The pterygoid plates can bend only to a limited extent with pressure, and this confining effect of the pterygoid plates of the sphenoid minimizes dramatically the ability of the palatine bones to separate at the midsagittal plane.www.indiandentalacademy.com
  • Zygomatic bone • The zygomatic bone was displaced laterally and posterosuperiorly, with the body and the temporal process of the zygomatic bone showing maximum overall displacements • The lateral structures of the maxilla (tuberosity and zygomatic buttress) were displaced posterosuperiorly. • The probable explanation for the posterosuperior displacement of the lateral maxillary structures compared with median structures that were displaced anteroinferiorly is the rotation of the 2 halves of the maxilla, with different centers of rotation in all 3 planes of space. www.indiandentalacademy.com
  • • The lateral nasal cavity wall was displaced laterally, indicating an increase in nasal cavity width. • This, along with lowering of the palatal plane, will reduce nasal airway resistance • The increase in nasal cavity width was more pronounced in the inferior portion than in the superior portion, widen as much as 8 to 10 mm at the level of the inferior turbinates. • The nasal bone and nasal process of maxilla moved medially after RME, which might lead to compression in the nasal region. • This explains the frequent pain and pressure in the nasal region experienced during palatal expansion therapy www.indiandentalacademy.com
  • Stress pattern along sutures • The maximum von Mises stresses were experienced by the medial aspect of the frontomaxillary suture, the superior portion of the nasomaxillary suture, the lateral aspect of the frontonasal suture, and the lateral surface of the sphenozygomatic suture • Loading of the zygomatic arch is more complex and is likely to include bending in several planes, with shearing and twisting www.indiandentalacademy.com
  • • Along the superior portions of the zygomatic arch at the zygomaticotemporal suture, the medial margins were associated with compressive stresses, whereas the lateral margins were associated with tensile stresses • The stress pattern was reversed along the inferior portions of the zygomatic arch, with the lateral and medial margins of the zygomaticotemporal suture showing compressive and tensile stresses, respectively. www.indiandentalacademy.com
  • Effects of RME on the roots and periodontium: • Isaacson and Ingram 1964, rapid expansion appliances are capable of generating up to 10kgs of force per activation on supporting teeth. Such high forces could cause resorption of roots of anchor teeth. • Barber and Sims (AJO1981) studied the effects of RME on the external root structure using scanning electron microscopy. • All anchor premolars exhibited root resorption, which was confined mainly to the buccal surface. • The fact that this resorption is sustained long after termination of active RME suggests the role of residual loads in the appliance.www.indiandentalacademy.com
  • • Garib et al AJODO 2006 studied periodontal changes by means of computed tomography after RME with tooth-tissue-borne and tooth-borne expanders. • RME reduced the buccal bone plate thickness of supporting teeth 0.6 to 0.9 mm • RME induced bone dehiscences on the anchorage teeth’s buccal aspect (7.1 4.6 mm at the first premolars and 3.8 4.4 mm at the mesiobuccal area of the first molars), especially in subjects with thinner buccal bone plates. • The tooth-borne expander produced greater reduction of first premolar buccal alveolar bone crest level than did the tooth-tissue-borne expanderwww.indiandentalacademy.com
  • Changes in mandible following Rapid maxillary expansion • Haas in 1961 using his midpalatal suture-opening appliance without any treatment in the lower arch, and observed that the mandibular arch tended to follow the maxillary teeth by tipping laterally. • In a later study,(1980) he reported that Some cases achieved and maintained an expansion of 3 to 4 mm in the lower intercanine width, and up to 6 mm in the intermolar width. • He claimed that mandibular intercanine width can be increased in the nongrower if the apical basewww.indiandentalacademy.com
  • • Lima et al AJODO 2004 investigated the spontaneous mandibular arch response to rapid palatal expansion as the sole orthodontic intervention and its stability long term post treatment ( mean 11.3 years) • Changes after maxillary expansion showed a significant increase of 1.47 mm in mandibular intermolar width (occlusal) and 0.97mm for lingual value. • The increase in intercanine width (lingual) of 0.26 mm. There were no statistically significant changes for occlusal intercanine width. www.indiandentalacademy.com
  • • The overall changes from pre-expansion to long-term follow-up were a significant mandibular intermolar width increase of 0.93 mm (lingual) and 0.72 mm (occlusal) • The intercanine width (lingual) decreased significantly, 0.99 mm. There were no statistically significant changes for mandibular intercanine width (occlusal) www.indiandentalacademy.com
  • Maturational changes in midpalatal suture • Scott (1956) considered that growth in suture ceases at the age of 1 year • Bjork (1964) pointed out that growth in midpalatal suture continues for a considerable longer period than formerly believed • Brite Melson AJO 1975 studying palatal growth with histological and microradiogaphic investigation on human autopsy material showed that transverse growth of midpalatal suture continued up to the age of 16 in girls and 18 in boys www.indiandentalacademy.com
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  • Treatment timing • Wertz and Dreskin (1977) noted greater and more stable orthopedic changes in patients under the age of 12 years • Bacetti ( AO 2001) showed that RME is able to induce significantly more favorable skeletal changes in transverse plane when it is initiated before the pubertal peak in skeletal growth • Clinicians have commonly reported difficulty in producing palatal separation following the pubertal growth period, while favorable orthopedic responses have been indicated prior to and during pubertal growth.www.indiandentalacademy.com
  • • A direct relationship between increased resistance to skeletal expansion and increasing patient age has been quantified and associated with the formation of mechanical interlockings at maxillary articulations as early as 12 to 13 years of age. • In addition the enhanced skeletal response in younger age groups has been associated with a greater cellular activity in the growing suture. • Ten Cate and associates reported that the sutural tissues in young growing rats were characterized by increased fibroblastic, fibroclastic, and osteoblastic activity following rapid expansion in contrast to a less marked activity in more mature animals. www.indiandentalacademy.com
  • Effect of rapid expansion done in children www.indiandentalacademy.com
  • Appliance design • Banded rapid maxillary expansion appliances – Haas type appliance – Hyrax type appliance – Minne expanders • Bonded rapid maxillary expanders • Butterfly type expanders • Fan shaped expanders • Nickel palatal expanderswww.indiandentalacademy.com
  • The Haas type expander • The first type of expansion appliance was popularized by Andrew Haas in 1961 • This appliance consisted of bands placed on maxillary first premolar and the first molar • A midline jackscrew is incorporated into two acrylic pads that closely contact the palatal mucosa • Support wires are extended anteriorly from molars along the buccal and lingual surfaces of posterior teeth to add rigidity to the appliance www.indiandentalacademy.com
  • The Haas type expander
  • • Haas states that more bodily movement and less dental tipping is produced when an acrylic palatal coverage is added, thus permitting forces to be generated not only against the teeth but also against underlying soft and hard palatal tissues • But the side effect includes inflammation of the palatal mucosa www.indiandentalacademy.com
  • Hyrax type expander • It is more commonly used type of banded RME appliances, the design of which has been credited to Biedermann. • This type of expander is made entirely of stainless steel, and does not include palatal acrylic, hence considered more hygienic by many practitioners • Bands are placed on maxillary first molars and first premolars • The appliance screw is placed in the palate in close proximity to palatal contour • Buccal and lingual support wires are added for rigidity www.indiandentalacademy.com
  • Hyrax type expander
  • • One of the concerns of Hyrax appliance is that it may be more flexible than the Haas appliance producing more dental tipping and less sutural expansion • Ralph (1998) used a finite element analysis to compare the difference between Hyrax and Haas appliance in affecting midpalatal suture, teeth and attached stuructures • He reported that average tipping effects are 2.5-3 times greater in Hyrax model compared to Haas model, while the later showed more tooth and sutural displacement • The Hyrax model also showed more deformation and thus decreased energy available on activationwww.indiandentalacademy.com
  • • Oliveria et al AJODO 2004 used a three dimensional assessment to compare the effects of Haas and Hyrax appliances. They reported that Haas appliance showed a greater component of true orthopedic movement while Hyrax caused dentoalveolar expansion • The orthopedic movement caused by Haas appliance was signified by greater gain in interpalatal width while dentoalveolar expansion caused by Hyrax appliance was revealed by greater interpalatal angulation after treatmentwww.indiandentalacademy.com
  • The Bonded acrylic splint expander • Bonded appliances were designed to cover the maxillary posterior occlusal-buccal segments so that the appliance not only serves as an expansion device but intrudes on the freeway space through its vertical thickness • It acts as a functional appliance with a small range of clinical application • 2-3 mm of acrylic is bonded to maxillary posterior teeth so that passive stretch of elevator and retractor musculature provides an apically directed force to maxilla and mandible ( Ahlgren 1970 and Graber 1977) www.indiandentalacademy.com
  • • The bonded Rapid maxillary expander would increase rigidity by limiting unwanted tipping and rotation of teeth due to increased surface of acrylic bonded to teeth • Further more tooth supra eruption would be limited because of bonding the entire posterior arch • Memikoglu and Iseri 1997 investigated the effects of Haas type RME and rigid acrylic bonded RME appliances • They reported an increase in tipping of upper molars and decrease in overbite in Haas group compared with Bonded groupwww.indiandentalacademy.com
  • • Sarver and Johnston AJODO 1989 examined the effect of acrylic spint expander in 20 patients who were on average 11 years of age at the beginning of treatment. Compared to the findings from a study by Wertz using Haas appliance, the bonded appliance showed a decrease in inferior displacement of maxilla • Steven Asanza et al 1997 investigated the effects of Hyrax type RME and Bonded expansion appliance and reported that increase in the vertical dimension often seen with more conventional Hyrax may be minimized or negated with bonded appliance www.indiandentalacademy.com
  • Combined Bonded RME and Vertical chin cap • Nisco and Nanda (1986) and Majourau and Nanda (1994) investigated the use of RME together with a high pull headgear and high pull chin cap. • They recommended the use of high pull chin cap to provide a more ideal force system • Basciftci and Karaman 2002 concluded that the vertical chin cap is an effective appliance for preventing the adverse vertical effect of RME in patient with a crossbite and vertical growth pattern www.indiandentalacademy.com
  • The Butterfly Expander for use in the mixed dentition: Cozza, Giancotti, Petrosino ( JCO 1999) It is a rapid palatal expansion appliance which follows the basic design of Hass, with a few modifications. It comprises a high midpalatal jackscrew(A0620), attached to a butterfly shaped stainless steel framework that extends forward to the palatal surfaces of deciduous canines.www.indiandentalacademy.com
  • The appliance is soldered to bands on the 2nd deciduous molars. The rigidity of the appliance and its location high in the palatal vault allows transverse force to be delivered closer to the center of resistance of the posterior teeth than with conventional expanders. The butterfly design thus minimizes posterior tipping and extrusion. As it is applied to the primary molars, it will not cause root resorption of anchored molars and premolars. It is recommended for use in the early mixed dentition.www.indiandentalacademy.com
  • Fan shaped expander Levrini, Filippi (JCO Nov 1999) • Patients with narrow maxillae sometimes require differential expansion of the anterior and posterior segments, as in cleft lip and palate cases. • To that end, Schellino and Modica have designed a ―spider screw‖ that works asymmetrically and allows fan opening. • Mechanism: The expander is made of stainless steel, with the spider screw as the active component. • There are three pivot points: a posterior one, which allows the ―fan‖ opening, and two anterior ones, which counteract the torquing forces produced during expansion. www.indiandentalacademy.com
  • Four arms, two mesial and two distal, are welded to the expander and to bands on the teeth. The type of expansion produced depends on the angulation and length of the arms.
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  • Nickel palatal Expander • It was developed by Dr Wendell Arndt (Kansas) in 1993, in order to overcome the limitations of conventional expansion appliances, in JCO, March 1993 issue as ― A tandem loop nickel titanium temperature activated palatal expander with the ability to produce light continuous pressure on the mid-palatal suture while simultaneously up righting, rotating an distalizing the maxillary 1st molars‖ • The Ni-Ti expander has a transition temperature of 94degress centigrade below which the interatomic forces weaken, making the metal much more flexible. When it is chilled before insertion in the patients mouth it can be easily bent to facilitate www.indiandentalacademy.com
  • • They come in 8 different intermolar widths from 26- 47 mm, The appropriate size is determined by measuring the amount of expansion needed, then adding 3mm for overcorrection. • When the appliance begins to stiffen in the patients mouth, it may initially cause some discomfort. • This can be alleviated by sipping a cold liquid which will temporarily make the NiTi more flexible. • If more than 8mm expansion is needed then two expanders must be used in succession. www.indiandentalacademy.com
  • Recommended treatment time are as follows: Expansion Retention Primary dentition 1-2mths 2mths Mixed Dentition 2-3mths 2mths Young Adults 3mths 2mths Adults 5 or more 3mths Advantages: 1 Self activated by body temperature. 2Automatically expands to its predetermined shape. 3.Require little manipulation by clinician. 4.Produces, constant pressure on teeth and mid palatal suture. 5. Permits patient to mitigate the pressure response. 6. As the bone deposition along suture is able to keep pace with the expansion, it avoids an unsightly midline gap.www.indiandentalacademy.com
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  • Clinical management of palatal expanders • A rapid palatal expander is usually the first appliance used when palatal expansion is planned for a patient in the permanent dentition. • For maximum orthopedic effect the abutment teeth should not have undergone prior movement. If teeth have been aligned before placement of the expander, the periodontal membrane usually is widened, and the likelihood of dental rather than orthopedic movement is increased. www.indiandentalacademy.com
  • Activation schedule • 1. Schedule by Timms – Patients less than 15 years of age: 90 degree rotation in morning and evening – Patients greater than 15 years of age: 45 degree activation 4 times a day • 2. Schedule by Zimring and Isaacson – Young growing patients: 2 turns per day for 4-5 days followed by 1 turn per day till expansion is achieved – Non growing adults: 2 turns per day for 2 days, then 1 turn per day for 5-7 days followed by one turn every alternate day till expansion is achieved www.indiandentalacademy.com
  • • McNamara and Burdon: they prefer once a day activation schedule till expansion is obtained; in order to avoid nasal distortion which has been associated with two expansion per day protocol www.indiandentalacademy.com
  • • Adequate expansion is said to be achieved when lingual cusps of upper posteriors approximate buccal cusps of lowers. • The key used by the parent for expansion may be either an extended safety key with acrylic handle, or it may be a traditional wire key. • After adequate expansion has been achieved, the appliance is left in place for an additional 3-5 months to allow for adequate reossification of the involved sutural systems. During this period, cold cure acrylic can be applied to the screw to stabilize the appliance. www.indiandentalacademy.com
  • • Removal of the Expander: An ordinary pair of posterior band removing pliers can be used to remove the expander. • Following removal, it is essential that fixed appliances be placed on the involved teeth within a very short period. • Usually stabilization is achieved during treatment using a transpalatal arch. • If fixed appliances are not to be used immediately, an acrylic plate is given for full time wear. www.indiandentalacademy.com
  • Slow Maxillary Expansion • The aspect of rapid expansion that was not appreciated initially was that orthodontic tooth movement continues after expansion is completed, until bone stability is achieved • It is possible for the tooth movement to allow bony segments to reposition themselves while the teeth are held in same relation to each other • This is what occurs approximately in 3 months required for bony in at the suture after rapid expansion www.indiandentalacademy.com
  • • During this time, the dental expansion is maintained, but the two halves of maxilla move back towards each other, which is possible because at the same time the teeth moves laterally on the supporting bone www.indiandentalacademy.com
  • Slow Vs Rapid Maxillary Expansion When expansion was completed, 10 mm of total expansion would have been produced by 8 mm of skeletal expansion and only 2 mm of dental expansion At 4 months, same 10 mm of expansion would still be present, but at that point there would be only 5 mm of skeletal expansion and tooth movement would account for 5 mm of total expansion
  • • Rapid activation of jack screw is therefore not an effective way to minimize tooth movement • Approximately 0.5 mm per week is the maximum rate at which tissues of mid palatal suture can adapt • If jack screw attached to teeth is activated one quarter turn of the screw (0.25mm) every other day, the ratio of dental to skeletal expansion is about 1:1 • Tissue damage and hemorrhage at suture are minimized and a large midline diastema never appears www.indiandentalacademy.com
  • • Thus a 10mm of expansion over a 10 week period, at rate of 1 mm per week, would consist of 5 mm of dental and 5 mm of skeletal expansion • This situation is analogous to rapid palatal expansion 2-3 months • Thus over all result of rapid Vs slow expansion is similar, but with slower expansion a more physiologic response is obtained www.indiandentalacademy.com
  • • Story (AJO 1973), Ekstrom (AJO 1977) have suggested that slow expansion procedures allow physiologic adjustment and reconstitution of the sutural elements over a period of 30 days. • Oshima 1972 showed that monkeys whose maxillas were expanded slowly (60) days showed less evidence of tipping of abutment teeth and greater sutural stability than monkeys that underwent rapid expansion (10 days). Similar results were obtained by Cotton (AJO 1978) in monkeys. • Increased fibroblastic, osteoblastic and osteoclastic activity seems to occur when the maxilla is widened slowly. Slower expansion has been associated with more physiologic stability and less relapse than RME. www.indiandentalacademy.com
  • Semi rapid maxillary expansion • Rapid displacement or deformation of the facial bones would result in a marked amount of relapse in the long term, whereas relatively slower expansion of the maxilla would probably produce less tissue resistance in the nasomaxillary complex. • Therefore, Iseri et al EJO 1998 suggested RME followed by slow maxillary expansion, immediately after the separation of the midpalatal suture, namely, semirapid maxillary expansion (SRME).www.indiandentalacademy.com
  • • The schedule would be two turns each day for the first five to six days, to open up the suture and followed by three turns each week for the remainder of the expansion treatment. • This would stimulate the adaptation process in the nasomaxillary complex and would result in reduction of relapse in the postretention period. • Iseri AO 2004 studied long term stability of semi rapid maxillary expansion in 40 patients with mean age of 14.57 years and mean followup period was 2.68 years after retention. • The findings of this study suggested that the dentoskeletal changes after the use of SRME were maintained satisfactorily in the long term in older adolescents and adults.www.indiandentalacademy.com
  • Effects of rapid maxillary expansion in skeletally mature patients • Lateral tipping of posterior teeth, • Extrusion, • Periodontal membrane compression, • Buccal root resorption, • Alveolar bone bending, • Fenestration of the buccal cortex, • Palatal tissue necrosis, • Inability to open the midpalatal suture, • Pain, and • Instability of the expansion.www.indiandentalacademy.com
  • • However, a few reports in the literature contradict these findings and state that nonsurgical maxillary expansion is as successful in adults as it is in children (Handelman AO 2000) • Because of more complications after attempts to orthopedically alter the transverse dimension of the maxilla with advancing age, surgical procedures have been recommended • These procedures have conventionally been grouped into 2 categories: – Segmenting the maxilla during a LeFort osteotomy to reposition the individual segments in a widened transverse dimension, and – Surgically assisted rapid palatal expansion (SARPE). www.indiandentalacademy.com
  • INDICATIONS FOR SARPE • 1. To increase maxillary arch perimeter, to correct posterior crossbite, and when no additional surgical jaw movements are planned. • 2. As a preliminary procedure, even if further orthognathic surgery is planned, to avoid increased risks, inaccuracy, and instability associated with segmental maxillary osteotomy. • 3. To provide space for a crowded maxillary dentition when extractions are not indicated. • 4. To widen maxillary hypoplasia associated with clefts of the palate. • 5. To reduce wide black buccal corridors • 6. To overcome the resistance of the sutures when RME has failed. www.indiandentalacademy.com
  • PATIENT SELECTION • Diagnosis – Clinical evaluation, model analysis, occlusograms, and radiographic measurements have been recommended for an accurate assessment. – Clinical evaluation includes assessment of the maxillary arch form and symmetry, shape of the palatal vault, width of the buccal corridors on smiling, occlusion, and mode of breathing – Study models should be used to thoroughly assess the arch form and the shape – The most common include the indexes of Pont, Linder-Harth, and Korkhauswww.indiandentalacademy.com
  • • Lehman 1984 recommended an occlusal radiograph to evaluate the ossification of midpalatal suture • This, however, is unreliable because of the superimposition of other bony structures and the lack of adequate visualization of the posterior part of the intermaxillary suture. • Betts et al 1995 suggested that posteroanterior cephalograms are reliable means to identify and evaluate transverse skeletal discrepancies between the maxilla and the mandible. • With advent of Cone-beam computed tomography one can generate scans that enable the clinician to perform a 3-dimensional evaluation of the apical bases including horizontal sections of the apical bases at different levels. www.indiandentalacademy.com
  • Age as criterion • The patient’s age has been considered by most authors and clinicians as the fundamental basis for distinguishing the use of orthopedic expansion vs SARPE • However, conflicting views regarding when orthopedic expansion is successful and when to request surgical assistance, are found in the literature. • Timms and Vero 1981 used 25 years as the upper limit for recommending orthopedic expansion • Mommaerts stated that RME is indicated for patients younger than 12 years, and, for those over 14 years, corticotomies are essential to release the areas of resistance to expansion.www.indiandentalacademy.com
  • • Further confusion is added by several case reports in which orthopedic maxillary expanders has been shown to be successful in much older adults. (Alpern and Yurosko 1987, Capelozza Filho 1999) • These authors suggested that, although an orthopedic effect was not observed, slow expansion results in a combination of membranous warpage and some sutural stretching to provide the desired end result. www.indiandentalacademy.com
  • • In treatment planning and case selection, the patient’s medical condition must be thoroughly evaluated • Several metabolic conditions have been linked to sutural synostoses. • These include hyperthyroidism, hypophosphatemic vitamin D- resistant rickets, and mucopolysaccharidoses and mucolipidoses • RME would either be unsuccessful or have unfavorable consequences even in a chronologically young patient with such medical conditions. www.indiandentalacademy.com
  • Amount of expansion • Betts et al 1995 have recommended that the amount of desired expansion is an important factor in case selection for maxillary expansion in adults. • In general, an orthodontist can camouflage transverse maxillomandibular discrepancies less than 5 mm with orthopedic or orthodontic forces alone. • When the transverse deficiency is greater than 5 mm, surgical assistance is essential. • Although both SARPE and segmental osteotomy are used, segmental osteotomy is reported to be unstable, especially when more than 8 mm expansion is desired www.indiandentalacademy.com
  • Two-stage vs singular surgery • Segmental osteotomy is the preferred choice for correction of transverse discrepancy when a single surgical procedure is planned to correct all maxillo- mandibular discrepancies • On the other hand, correction of transverse discrepancy is done as a first step with SARPE and a separate second surgery is necessary for discrepancies of the maxilla and the mandible in the other planes of space. • Bailey et al 1997 have recommended that SARPE should be used for patients with an isolated transverse deficiency when OME is not indicated, or with unilateral or asymmetric narrowing of the maxilla. www.indiandentalacademy.com
  • • Proponents of SARPE have also hypothesized that post-SARPE orthopedic forces can be applied to the maxilla, since the 2 halves of the maxilla have been loosened. • These forces might be valuable in correcting sagittal or vertical discrepancies without additional surgery. • This, however, has not been used routinely because the prognosis is uncertain. www.indiandentalacademy.com
  • Periodontal status • Muller and Eger 2002 introduced the concept of periodontal biotype • They pointed out that it is essential to record the thickness of the gingival tissues during clinical evaluation of the periodontium. • Therefore, evaluations of the gingival tissues and the biotype are essential to determine the ability of the tissues to withstand the pressure of orthopedic maxillary expansion; otherwise, surgical release of the sutures is needed to remove interferences to maxillary expansion. www.indiandentalacademy.com
  • Orthodontic considerations and preparation • The mandibular dentition should be decompensated before surgery to allow assessment of the amount of transverse expansion necessary, to establish arch coordination, and to assist in preventing postexpansion relapse with dental interdigitation • Before sending a patient for a SARPE, the orthodontist must ensure that there is enough space between the roots of the central incisors for a midline split. • If space is inadequate, preoperative root divergence must be createdwww.indiandentalacademy.com
  • SURGICAL TECHNIQUE • The surgical technique for SARPE involving a midpalatal split was described by Brown in 1938. • Many surgical procedures have been designed to resect the areas of resistance to lateral expansion in the midface. • The areas of resistance have been classified as – Anterior support (piriform aperture pillars), – Lateral support (zygomatic buttresses), – Posterior support (pterygoid junctions), and – Median support (midpalatal synostosed suture). www.indiandentalacademy.com
  • • Initial reports described the midpalatal suture as the area of greatest resistance to maxillary expansion. • However, later reports highlighted the zygomatic buttress and the pterygomaxillary junction as critical areas of resistance. • Kennady et al AJO 1976 evaluated the influence of lateral maxillary and pterygomaxillary osteotomies with and without palatal osteotomy vs unoperated controls or palatal osteotomy alone and found significant differences. • They concluded that reducing or eliminating the resistance to lateral movement by osteotomy allows for movement of the basal bone of the maxilla. www.indiandentalacademy.com
  • • Timms 1981 suggested that there are 3 stages of surgical assistance for maxillary expansion based on the patient’s age. – Stage 1 (median osteotomy) is performed for patients aged 25 years or older, or younger if rapid maxillary expansion was tried and failed. – Stage 2 (median and lateral osteotomies) is reserved for those aged 30 years and older, and – Stage 3 (median, lateral maxillary and anterior maxillary osteotomies) is for patients aged 40 years and older. • Betts and Ziccardi 2000 recommended a total bilateral maxillary osteotomy from the pyriform aperture to the pterygomaxillary fissure along with a midpalatal split from the anterior to the posterior nasal spines, sectioning all articulations and areas of resistance—anterior, lateral, posterior and median www.indiandentalacademy.com
  • • Bays et al 1992 and Northway et al 2000 recommended that no attempt should be made to separate the maxilla from the pterygoid plates to avoid invasion into the pterygomaxillary junction. • According to them, such a separation requires extreme force and usually causes the plates to fracture. • There is no consensus about either the extent or the procedure for SARPE. • There are also no conclusive means to determine the areas of resistance to lateral maxillary expansion or ascertain an individualization of the surgical cuts. • The extent of surgery ideally should depend on the areas of resistance with some individualization. www.indiandentalacademy.com
  • RETENTION, STABILITY, AND RELAPSE • The issue of long-term stability and relapse with SARPE has not been studied in detail in the literature. • In general, most reports state that surgical expansion is more stable than orthopedic maxillary expansion • Some authors recommended that retention is not necessary for SARPE, and the orthodontist can begin orthodontic treatment without a holding phase. • The relapse rates for SARPE vary from 5% to about 25%. These rates are significantly lower than that of orthopedic expansion, which can be as high as 63% www.indiandentalacademy.com
  • • The high rate of relapse associated with orthopedic maxillary expansion is due to its use in skeletally advanced patients. • In a study by Berger et al AJODO 1998, both orthopedic maxillary expansion and SARPE were compared in an age-appropriate sample. • The orthopedic maxillary expansion sample comprised subjects aged 6 to 12 years, and the SARPE group’s ages ranged from 13 to 35 years. • These authors found no difference in the stability of SARPE and orthopedic maxillary expansion . www.indiandentalacademy.com
  • COMPLICATIONS OF SARPE • Complications associated with SARPE include significant hemorrhage, gingival recession, root resorption, injury to the branches of the maxillary nerve, infection, pain, devitalization of teeth and altered pulpal blood flow, periodontal breakdown, sinus Infection, alar base flaring, extrusion of teeth attached to the appliance, relapse, and unilateral expansion. • Palatal tissue irritation is a frequent complication of SARPE. • This can be either due to impingement from the appliance or associated with a rapid rate of expansion www.indiandentalacademy.com
  • Unusual complications • The incidence of frank aseptic tissue necrosis has been reported to be about 1.8% • Occasionally, aberrant fractures of the maxillary articulation are seen • Aberrant and asymmetric fracture of the interdental bone between the central incisors leads to increased mobility, gingival recession, dehiscence, and periodontal defects on the incisors. • Some unusual complications that have been reported include orbital compartment syndrome resulting in permanent blindness, bilateral lingual anesthesia, and a nasopalatine canal cyst www.indiandentalacademy.com
  • Bone borne palatal distractor • Mommaerts 1999 suggested the use of a bone- borne titanium device with interchangeable expansion modules rather than a conventional tooth-borne appliance. • According to him, conventional tooth-borne appliances produce greater loss of anchorage and more skeletal relapse both during and after expansion. • Higher incidences of cortical fenestration and buccal root resorption are also observed with tooth-borne appliances compared with absolute bone-borne appliances. www.indiandentalacademy.com
  • • Orthodontic treatment can be initiated earlier in the postsurgical period with the bone-borne appliances than tooth-borne appliances. • The application of the bone-borne distractor does not depend on a complete dentition • They have been reported to have greater control of orthopedic movement than tooth-borne appliances • The bone-borne appliances are contraindicated in patients with extremely low palates, because the nails of the abutment plates loosen more easily and the distractor is not stable. • These are also contraindicated in patients with immunodeficiency conditions and prior radiation therapy. www.indiandentalacademy.com
  • Case report by Emel Sari AO 2007 www.indiandentalacademy.com
  • • The transpalatal distractor (TPD) allows for maxillary expansion according to the concepts of distraction osteogenesis • The Transpalatal distractor applies expansion forces high in the palatal vault and segmental tilting in the frontal plane is therefore minimal. • Pinto et al 2001 analyzed the immediate postexpansion positional changes of the maxillary halves resulting from the use of the transpalatal distractor and concluded that the expansion at the canine level was 1.5 times greater than at the molar level and expansion in the frontal plane occurs with little tipping of the segments. www.indiandentalacademy.com
  • When the distractor is placed on the palate at the level of the second premolar and pterygomaxillary disjunction is not performed, more expansion occurs in the anterior part of the maxilla than it does in the posterior. Matteini AJODO 2001 showed that pterygomaxillary disjunction and placement of the Transpalatal distractor on the palate at the level of the first molars result in more parallel expansion of the maxillary segments
  • Conclusion • Maxillary arch constriction or maxillary width deficiency associated with a high palatal vault is generally treated orthodontically by expansion of the midpalatal suture. • This procedure, introduced by Angell in 1860, was reintroduced during the 1960s by Haas. • Maxillary width deficiencies are routinely corrected in growing patients with appliances that help in separation of the midpalatal and associated maxillary sutures.www.indiandentalacademy.com
  • • However, this technique is not useful in skeletally mature individuals. • Alternatives in these situations include the use of surgically assisted rapid maxillary expansion (SARME) or a segmental LeFort I osteotaomy in an attempt to overcome the resistance of the closed sutures www.indiandentalacademy.com
  • References 1. Haas AJ. Rapid expansion of the maxillary dental arch and nasal cavity by opening of the mid-palatal suture. Angle Orthod 1961;31:73- 90. 2. Bishara SE, Staley RN. Maxillary expansion: clinical implications. Am J Orthod Dentofacial Orthop 1987;91:13-4. 3. Hicks EP. Slow maxillary expansion: a clinical study of the skeletal vs dental response in low magnitude force. Am J Orthod 1978;73:121-41. 4. Timms DJ. A study of basal movement with rapid maxillary expansion. Am J Orthod 1980;77:500-7. www.indiandentalacademy.com
  • 5. Pawan Gautam, Ashima Valiathan,and Raviraj Adhikari. Stress and displacement patterns in the craniofacial skeleton with rapid maxillary expansion: A finite element method study. Am J Orthod Dentofacial Orthop 2007; 132:5.e1-5.e11 6. Lokesh Suria and Parul Tanejab. Surgically assisted rapid palatal expansion: A literature review. Am J Orthod Dentofacial Orthop 2008;133:290-302 7. Daniela Garib, José Castanha Henriques,Guilherme Janson, Marcos Roberto de Freitas. Periodontal effects of rapid maxillary expansion with tooth-tissue-borne and tooth-borne expanders: A computed tomography evaluation: Am J Orthod Dentofacial Orthop 2006;129:749-58 www.indiandentalacademy.com
  • 8. Lee KG, Ryu YK, Park YC, Rudolph DJ. A study of holographic interferometry on the initial reaction of maxillofacial complex during protraction. Am J Orthod Dentofacial Orthop 1997; 111:623-32. 9. Wertz RA. Skeletal and dental changes accompanying rapid mid-palatal suture opening. Am J Orthod 1970;58:41-66. 10.Haas AJ. Palatal expansion: just the beginning of dentofacial orthopedics. Am J Orthod 1970;57:219-55. 11.Chung CH, Font B. Skeletal and dental changes in the sagittal, vertical, and transverse dimensions after rapid palatal expansion. Am J Orthod Dentofacial Orthop 2004;126:569-75. www.indiandentalacademy.com
  • 12.Iseri H, Tekkaya AE, Oztan O, Bilgic S Biomechanical effects of rapid maxillary expansion on the craniofacial skeleton, studied by the finite element method. Eur J Orthod 1998;20:347-56. 13.Krebs AA. Expansion of midpalatal suture studied by means of metallic implants. Acta Odontol Scand 1959;17:491-501. 14.Baccetti T, Franchi L, Cameron CG, McNamara JA Jr. Treatment timing for rapid maxillary expansion. Angle Orthod 2001; 71:343-50. 15.Pavlin D, Vukicevic D. Mechanical reactions of facial skeleton to maxillary expansion determined by laser holography. Am J Orthod 1984;85:498-507. www.indiandentalacademy.com
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  • 24.Haas AJ. Long-term posttreatment evaluation of rapid palatal expansion. Angle Orthod 1980;50:189-217. 25.Capelozza Filho L, Cardoso Neto J, da Silva Filho OG, Ursi WJ. Non-surgically assisted rapid maxillary expansion in adults. Int J Adult Orthod Orthognath Surg 1996;11:57-66. 26.Handelman CS, Wang L, BeGole EA, Haas AJ. Nonsurgical rapid maxillary expansion in adults: report on 47 cases using the Haas expander. Angle Orthod 2000;70:129-44. 27.Lehman JA Jr, Haas AJ, Haas DG. Surgical orthodontic correction of transverse maxillary deficiency: a simplified approach. Plast Reconst Surg 1984;73:62-8. www.indiandentalacademy.com
  • 28.Usumez S, Iseri H, Orhan M, Basciftci FA. Effect of rapid maxillary expansion on nocturnal enuresis. Angle Orthod 2003; 73:532-8. 29.Timms DJ. Effect of rapid maxillary expansion on hearing loss. Angle Orthod 1997;67:244-6. 30.Glassman AS, Nahigian SJ, Medway JM, Aronowitz HI. Conservative surgical orthodontic adult rapid palatal expansion: sixteen cases. Am J Orthod 1984;86:207-13. 31.Sandstrom RA, Klapper L, Papaconstantinou S. Expansion of the lower arch concurrent with rapid maxillary expansion. Am J Orthod Dentofacial Orthop 1988;94:296-302.www.indiandentalacademy.com
  • 32.Baccetti T, Franchi L, Cameron CG, McNamara JA Jr. Treatment timing for rapid maxillary expansion. Angle Orthod 2001; 71:343-50. 33.Bell RA. A review of maxillary expansion in relation to rate of expansion and patient’s age. Am J Orthod. 1982;81:32–36 34.Ten Cate AR, Freeman E, Dickinson JB. Sutural development: structure and its response to rapid expansion. Am J Orthod 1977;71:622-36. 35.Sarver DM, Johnston MW. Skeletal changes in vertical and anterior displacement of the maxilla with bonded rapid palatal expansion appliances. Am J Orthod Dentofacial Orthop. 1989;95(6):462– 466. www.indiandentalacademy.com
  • 36.Wertz R. Mid-palatal suture opening: a normative study. Am J Orthod 1977;71:367-81. 37.Biederman W. Rapid correction of Class 3 malocclusion by midpalatal expansion. Am J Orthod. 1973;63(1):47–55. 38.Basciftci FA, Karaman AI. Effects of a modified acrylic bonded rapid maxillary expansion appliance and vertical chin cap on dentofacial structures. Angle Orthod. 2002;72(1):61–71. 39.Daniela Garib; Jose Fernando Henriques; Paulo Carvalho; Simone Gomes. Longitudinal Effects of Rapid Maxillary Expansion- A Retrospective Cephalometric Study. Angle Orthodontist, 2007: Vol 77, No 3, 442-448 www.indiandentalacademy.com
  • 40.Linder-Aronson S, Lindgren J. The skeletal and dental effects of rapid maxillary expansion. Br J Orthod. 1979;6(1): 25–29. 41.Garib DG, Henriques JFC, Janson G, Freitas MR, Coelho RA. Rapid maxillary expansion— tooth tissue-borne versus tooth-borne expanders: a computed tomography evaluation of dentoskeletal effects. Angle Orthod. 2005;75(4):548–557. 42.Stanley Braun, Alexandre Bottrel, Kong-Geun Lee, José J. Lunazzi, and Harry L. Legan. The biomechanics of rapid maxillary sutural expansion: Am J Orthod Dentofacial Orthop 2000;118:257-61 www.indiandentalacademy.com
  • 43.Ekström C, Henrikson C, Jensen R. Mineralization in the midpalatal suture after orthodontic expansion. Am J Orthod 1977;71:449-455 44.Emel Sarı; Cihan Ucar; Cenk Ceylanoglu. Transpalatal Distraction in a Patient with a Narrow Maxilla: Angle Orthodontist, 2007 Vol 77, No 6, 1126-1131. 45.Claudio Matteini, and Maurice Y. Mommaerts . Posterior transpalatal distraction with pterygoid disjunction: A short-term model study. Am J Orthod Dentofacial Orthop 2001;120:498-502www.indiandentalacademy.com
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