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Conventional bone-anchored palatal distractor using an orthodontic palatal expander for the transverse maxillary distraction osteogenesis: technical note
Conventional bone-anchored palatal distractor using an orthodontic palatal expander for the transverse maxillary distraction osteogenesis: technical note Seiji Iida, DDS, PhD,a Seiji Haraguchi, DDS, PhD,b Tomonao Aikawa, DDS, PhD,c Kohtaro Yashiro, DDS, PhD,d Masaya Okura, DDS, PhD,e and Mikihiko Kogo, DDS, PhD,f Osaka, Japan OSAKA UNIVERSITY GRADUATE SCHOOL OF DENTISTRY
Objective. Surgical-assisted rapid palatal expansion includes various treatment procedures for solving transverse maxillary deficiencies, especially in cases with a matured palatal suture. Recent introduction of the concept of distraction osteogenesis has contributed to generalize this useful treatment and to develop some bone-borne devices that will not cause the problems found in cases treated by tooth-supported palatal expander. This report shows a conventional bone-borne distractor using commercially available orthodontic palatal expansion screws. Method. The distractor consists of 2 parts: one is a commercially available orthodontic palatal expansion screw (Hyrax type, Fan style) and another is a screw-ring, which is one of the attached parts of the mandibular distraction system. The bone screws are inserted transmucosally to the palatal bone via the screw-rings. Result. The palatal distractor can be applied to varied palatal shapes and can expand the palate without any trouble. Conclusion. This conventional palatal distractor may contribute to generalize the transpalatal maxillary distraction osteogenesis for cases with maxillary teeth problems. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;105: e8-e11)
Surgical-assisted rapid palatal expansion (SARPE) includes various treatment procedures for solving transverse maxillary deficiencies,1,2 especially in cases with a matured palatal suture. Among SARPE, the simultaneous rapid palatal expansion using a tooth-supported device was the common treatment, but the maximum amount of transverse expansion that is practical with a segmental LeFort 1 is reported as 5 to 7 mm.3 Since the introduction of the concept of distraction osteogenesis in the oral and maxillofacial region, this procedure has been modified into palatal expansion, which enables wider expansion by the general protocol for distraction. There is some confusion of the term SARPE by means of distraction. Some a
Associate Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry. b Associate Professor, Department of Orthodontics, Osaka University Graduate School of Dentistry. c Assistant Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry. d Associate Professor, Department of Orthodontics, Osaka University Graduate School of Dentistry. e Associate Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry. f Professor and Head, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry. Received for publication May 7, 2007; returned for revision Aug 5, 2007; accepted for publication Aug 25, 2007. 1079-2104/$ - see front matter © 2008 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2007.08.022
e8
reports used the term transverse maxillary distraction (TMD)4,5 or transpalatal distraction (TPD)6-8 to distinguish from the other types of SARPE, but there is no doubt that this treatment will become one of the standard surgical-assisted orthodontic treatments. Tooth-supported appliances using a traditional orthodontic palatal expander like Hyrax screws have been the standard equipment for this treatment,4 but recently some bone-borne devices 5,9-11 have been developed to solve the problems caused by using a tooth-supported palatal expander, such as abutment tooth tipping and deterioration of gingival condition because of the direct force of expansion to the teeth and long consolidation period in which these teeth must fabricate the orthodontic bands. It is no doubt that these bone-borne devices have contributed to generalize this treatment for adult cases having problems of periodontal tissue. However, it is clear that some problems exist with the bone-borne device such as high price and less stability during the consolidation periods.7 In this report, we describe conventional bone-anchored palatal distractors for transverse maxillary distraction using a common orthodontic palatal expander and the screw-ring, which is one of the attached parts of the commercially available mandibular distraction system. DEVICE FOR PALATAL EXPANSION The device consists of 2 parts: one is an orthodontic palatal expander and the another is a screw-ring, which
OOOOE Volume 105, Number 2
Iida et al. e9
plane. The nasal septum is separated and the tip of the anterior nasal spine is excised. After mobilization of both lateral segments, the palatal device is located at the position determined before the operation. The bone screws are inserted transmucosally via the screw-rings with an angled engine and an angled driver. An excessive force in securing the screws can depress the distractor easily due to condensation of the palatal mucosa, which may change the direction for distraction. Therefore, the self-tapping screws should be driven carefully into the planned positions. Then, the distractor is activated approximately 2 to 3 mm intraoperatively to confirm the mobilization of each segment. The expansion screw is then turned back to its starting position. To strengthen the mechanical vulnerability of the arms and the fixation of the screws during distraction, self-curing resins are used to cover those components (Figs. 2, A and 3, A). After 1 week of latency period, the appliance is activated by 1 mm per day, until the distal segment is moved to the designed position. After DO, the lingual arch orthodontic appliance is placed to maintain the expansion (Fig. 2, B and 3, B). Orthodontic treatment can be reinitiated after 3 months of consolidation period.
Fig. 1. A, Simple palatal device for TMDO consisted with the palatal expander and 4 screw-rings. B, The positions of the screw insertion into palatal bone are determined on the dental cast model prior to the operation to avoid the damage for dental root.
is one of the attached parts of the “DynaForm system” (Leibinger Stryker GmbH, Freiburg, Germany) mandibular distraction system12,13 (Fig. 1, A). Both parts are commercially available materials. The 4 metal arms of a palatal expander are bent onto appropriate positions of the palatal surface of the cast model. After trimming and adjusting the diameter of these metal arms, the screw-rings are inserted in each arm. The base of the screw-rings are compressed in order to fixed with the metal arm only by mechanical compression force. The position of screw-rings should be located where the inserted long screw will not injure the roots of adjacent maxillary teeth (Fig. 1, B). SURGICAL PROCEDURE The osteotomy is carried out using standard technique with osteotomies of the lateral maxilla, lateral nasal wall, pterygoid plates, and a single osteotomy of the palate slightly to one side of the middle sagittal
DISCUSSION Since the introduction of the concept of distraction osteogenesis for palatal expansion, SARPE has enabled wider expansion of the maxillary dental arch, and this surgically assisted orthodontic treatment has become a standard and important procedure for correction of the narrow maxillary width in adult cases.2 As well as less limitation of elongation of the palatal bone, the generated bone at the anterior maxillary alveolar, which will be used for teeth alignment, may be the reason for the widespread use of SARPE in the orthodontic field. Most common equipment used in SARPE has been the hygienic appliance using Hyrax expansion screws,4 in which all wire flames are soldered to bands that are cemented on the abutment teeth. The expander can be a non-spring-loaded jackscrew. The abutment teeth are generally the first molar and premolars. Therefore, with this equipment, the force for expansion directly acts on these teeth, which will cause tooth tipping, extrusion, periodontal membrane compression, buccal root resorption, fenestration of the buccal cortex, and instability-relapse with the necessity for overcorrection6 and the long periods with fabrication of bands on abutment teeth cause periodontal disease. To solve the problems caused by mechanical stress on teeth, recently a bone-borne appliance for SARPE has been marketed. In both the Transpalatal Distractor (TPDR, Surgi-Tec NV, Burges, Belgium)5-7 and the
e10
Iida et al.
Fig. 2. A case treated by a bone-anchored palatal distractor consisted of a Hyrax type palatal expansion screw and screwrings. A, Intraoral finding before distraction. Bone screws inserted into palatal bone transmucosaly were fixed with the screw-ring by the self-curing acrylic resin to prevent loosening. B, Intraoral finding after distraction. The amount of palatal expansion was 8 mm and the lingual arch orthodontic appliance is placed to maintain the expanded width of the maxillary dental arch and the space between central incisors.
Magdeburg type (KLS Martin, Tuttlingen, Germany),9,10 the screws are used for securing the device to palatal bone. In TPDR, a cylindrical screw for expansion is secured to bone by only 1 screw in each segment and the expansion force acts on a small area. The Magdeburg type consists of a cylindrical screw with 2 miniplates. This device can be secured with palatal bone by 4 screws in each side. The difference of the stability of the distractor influences of the occurrence of obstacles and problems during the treatment. Neyt et al.7 reported the occurrence of loosened distractor in some cases treated by TPDR. The Rotterdam Palatal
OOOOE February 2008
Fig. 3. A case treated by a bone-anchored palatal distractor consists of a Fan-type palatal expansion screw and screwrings. A, Intraoral finding before distraction. B, Intraoral finding after distraction. The amount of palatal expansion was 5 mm at the central incisor level, but the intermolar width was not increased by using this type of distractor.
Distractor (KLS Martin)11 has a unique appearance, which is manufactured simply based on the concept of a car jack. Different from bone-borne appliances, this system has no risk of damage to dental roots and the anterior palatine nerve due to the bone screw insertion, but may have a risk of loosening of the appliance during the consolidation period. Our device has 2 bone anchors by transmucosaly inserting bone screws in each side and may have enough stability during consolidation periods, but the additional adhesion by self-curing resin between the bone screw and screw-ring should be necessary to prevent the loosening of the screw that can be caused by the inflammatory changes of the palatal mucosa around the screws. There are 2 major aims of SARPE: one is producing the space at the anterior portion for alignment and the other is widening the upper dental arch. There may be some differences in the appearance of the dental arch after the consolidation period with the distractor. Pinto
OOOOE Volume 105, Number 2
et al.8 showed the trend that the post expansion of width of the posterior teeth are more than those of the anterior teeth in both rapid palatal expansion and SARPE procedures,8 because of the buccal tilting of the appliancecarrying abutment teeth. To the contrary, the expansion of the anterior potion was greater than that of the molar portion in the case expanded by TPD. Indeed the pterygo-maxillary separation was not performed in their procedure. The characteristic shape of their device, which has a small abutment plate, causes the concentration of expansion forces at a narrow area. Therefore, it is easy to consider the dental arch appearance may be directly influenced by the anchor location as well as the pterygo-maxillary separation. It seems that the Magdeburg type may produce the parallel movement of segments and may maintain the shape during the consolidation period due to the multiple bone anchorages. Our device has 2 anchorages in each side that can widen the segments in parallel but differences of numbers and location of the bone anchorages may influence the appearance of the dental arch after the consolidation period. The fan-style expansion screw was designed and developed to obtain greater expansion in the intercanine width than in the intermolar width.14 Different from other expansion screws, which expand each segment laterally in parallel, this expansion screw allows “fan opening” and is applied for the treatment of cases with anterior maxillary narrowness with normal intermolar width. Among the commercially available bone-anchored expanders, TPD, which has a small area of anchorage in the palatal bone, can effectively expand the anterior maxilla when the distractor is positioned at the anterior maxilla. However, it is clear that the fantype expander can obtain more certain expansion at the anterior maxilla without increasing posterior maxillary width. Therefore, our bone-anchored fan-type screws can more effectively realize the requirement of the orthodontist. In conclusion, the screw-rings of the DynaForm System can be applied to the various orthodontic expansion screws and changes these expansion screws into the bone-anchored distractor. Therefore the concept of a bone-anchored appliance using screw-ring and orthodontic expansion screws may increase the variations of palatal distraction and generalize the transverse maxillary distraction using bone-anchored equipment in these cases.
Iida et al. e11 REFERENCES 1. Bell WH, Epker BN. Surgical-orthodontic expansion of the maxilla. Am J Orthod 1976;70:517-28. 2. Koudstaal MJ, Poort LJ, van der Wal KG, Wolvius EB, PrahlAndersen B, Schulten AJ. Surgically assisted rapid maxillary expansion (SARME): a review of the literature. Int J Oral Maxillofac Surg 2005;34:709-14. 3. Jacobs JD, Bell WH, Williams CE, Kennedy JW. Control of the transverse dimension with surgery and orthodontics. Am J Orthod 1980;77:284-306. 4. Conley RS, Legan HL. Correction of severe vertical maxillary excess with anterior open bite and transverse maxillary deficiency. Angle Orthod 2002;72:265-74. 5. Ramieri GA, Spada MC, Austa M, Bianchi SD, Berrone S. Transverse maxillary distraction with a bone-anchored appliance: dento-periodontal effects and clinical and radiological results. Int J Oral Maxillofac Surg 2005;34:357-63. 6. Mommaerts MY. Transpalatal distraction as a method of maxillary expansion. Br J Oral Maxillofac Surg 1999;37:268-72. 7. Neyt NM, Mommaerts MY, Abeloos JV, De Clercq CA, Neyt LF. Problems, obstacles and complications with transpalatal distraction in non-congenital deformities. J Craniomaxillofac Surg 2002;30:139-43. 8. Pinto PX, Mommaerts MY, Wreakes G, Jacobs W. Immediate postexpansion changes following the use of the transpalatal distractor. J Oral Maxillofac Surg 2001;59:994-1000. 9. Gerlach KL, Zahl C. Transversal palatal expansion using palatal distractor. J Orofac Orthop 2003;64:443-9. 10. Gerlach KL, Zahl C. Surgically assisted rapid palatal expansion using a new distraction device: report of a case with an epimucosal fixation. J Oral Maxillofac Surg 2005;63:711-3. 11. Koudstaal MJ, van der Wal KGH, Wolvius EB, Schlten AJM. The Rotterdam palatal distractor of the new bone-borne device and report of pilot study. Int J Oral Maxillofac Surg 2006;35: 31-5. 12. Guerrero CA, Bell WH, Contasti GI, Rodriguez AM. Mandibular widening by intraoral distraction osteogenesis. Br J Oral Maxillofac Surg. 1997;35:383-92. 13. Guerrero CA, Bell WH, Gonzalez M, Rojas A. Three-Dimensional intraoral distraction osteogenesis. an orthodontic-surgical approach. In: Samchukov ML, Cope JB, Cherkashin AM, editors. Craniofacial distraction osteogenesis. St. Louis: Mosby; 2001. p. 236-46. 14. Doruk C, Bicakci AA, Basciftci FA, Agar U, Babacan H. A comparison of the effects of rapid maxillary expansion and fan-type rapid maxillary expansion on dentofacial structures. Angle Orthod 2004;74:184-94.
Reprint requests: Seiji Iida, DDS, PhD The First Department of Oral and Maxillofacial Surgery Osaka University Graduate School of Dentistry 1-8 Yamadaoka, Suita Osaka 565-0871, Japan [email protected]
Objective. Surgical-assisted rapid palatal expansion includes various treatment procedures for solving transverse maxillary deficiencies, especially in cases with a matured palatal suture. Recent introduction of the concept of distraction osteogenesis has contributed to generalize this useful treatment and to develop some bone-borne devices that will not cause the problems found in cases treated by tooth-supported palatal expander. This report shows a conventional bone-borne distractor using commercially available orthodontic palatal expansion screws. Method. The distractor consists of 2 parts: one is a commercially available orthodontic palatal expansion screw (Hyrax type, Fan style) and another is a screw-ring, which is one of the attached parts of the mandibular distraction system. The bone screws are inserted transmucosally to the palatal bone via the screw-rings. Result. The palatal distractor can be applied to varied palatal shapes and can expand the palate without any trouble. Conclusion. This conventional palatal distractor may contribute to generalize the transpalatal maxillary distraction osteogenesis for cases with maxillary teeth problems. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;105: e8-e11)
Surgical-assisted rapid palatal expansion (SARPE) includes various treatment procedures for solving transverse maxillary deficiencies,1,2 especially in cases with a matured palatal suture. Among SARPE, the simultaneous rapid palatal expansion using a tooth-supported device was the common treatment, but the maximum amount of transverse expansion that is practical with a segmental LeFort 1 is reported as 5 to 7 mm.3 Since the introduction of the concept of distraction osteogenesis in the oral and maxillofacial region, this procedure has been modified into palatal expansion, which enables wider expansion by the general protocol for distraction. There is some confusion of the term SARPE by means of distraction. Some a
Associate Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry. b Associate Professor, Department of Orthodontics, Osaka University Graduate School of Dentistry. c Assistant Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry. d Associate Professor, Department of Orthodontics, Osaka University Graduate School of Dentistry. e Associate Professor, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry. f Professor and Head, First Department of Oral and Maxillofacial Surgery, Osaka University Graduate School of Dentistry. Received for publication May 7, 2007; returned for revision Aug 5, 2007; accepted for publication Aug 25, 2007. 1079-2104/$ - see front matter © 2008 Mosby, Inc. All rights reserved. doi:10.1016/j.tripleo.2007.08.022
e8
reports used the term transverse maxillary distraction (TMD)4,5 or transpalatal distraction (TPD)6-8 to distinguish from the other types of SARPE, but there is no doubt that this treatment will become one of the standard surgical-assisted orthodontic treatments. Tooth-supported appliances using a traditional orthodontic palatal expander like Hyrax screws have been the standard equipment for this treatment,4 but recently some bone-borne devices 5,9-11 have been developed to solve the problems caused by using a tooth-supported palatal expander, such as abutment tooth tipping and deterioration of gingival condition because of the direct force of expansion to the teeth and long consolidation period in which these teeth must fabricate the orthodontic bands. It is no doubt that these bone-borne devices have contributed to generalize this treatment for adult cases having problems of periodontal tissue. However, it is clear that some problems exist with the bone-borne device such as high price and less stability during the consolidation periods.7 In this report, we describe conventional bone-anchored palatal distractors for transverse maxillary distraction using a common orthodontic palatal expander and the screw-ring, which is one of the attached parts of the commercially available mandibular distraction system. DEVICE FOR PALATAL EXPANSION The device consists of 2 parts: one is an orthodontic palatal expander and the another is a screw-ring, which
OOOOE Volume 105, Number 2
Iida et al. e9
plane. The nasal septum is separated and the tip of the anterior nasal spine is excised. After mobilization of both lateral segments, the palatal device is located at the position determined before the operation. The bone screws are inserted transmucosally via the screw-rings with an angled engine and an angled driver. An excessive force in securing the screws can depress the distractor easily due to condensation of the palatal mucosa, which may change the direction for distraction. Therefore, the self-tapping screws should be driven carefully into the planned positions. Then, the distractor is activated approximately 2 to 3 mm intraoperatively to confirm the mobilization of each segment. The expansion screw is then turned back to its starting position. To strengthen the mechanical vulnerability of the arms and the fixation of the screws during distraction, self-curing resins are used to cover those components (Figs. 2, A and 3, A). After 1 week of latency period, the appliance is activated by 1 mm per day, until the distal segment is moved to the designed position. After DO, the lingual arch orthodontic appliance is placed to maintain the expansion (Fig. 2, B and 3, B). Orthodontic treatment can be reinitiated after 3 months of consolidation period.
Fig. 1. A, Simple palatal device for TMDO consisted with the palatal expander and 4 screw-rings. B, The positions of the screw insertion into palatal bone are determined on the dental cast model prior to the operation to avoid the damage for dental root.
is one of the attached parts of the “DynaForm system” (Leibinger Stryker GmbH, Freiburg, Germany) mandibular distraction system12,13 (Fig. 1, A). Both parts are commercially available materials. The 4 metal arms of a palatal expander are bent onto appropriate positions of the palatal surface of the cast model. After trimming and adjusting the diameter of these metal arms, the screw-rings are inserted in each arm. The base of the screw-rings are compressed in order to fixed with the metal arm only by mechanical compression force. The position of screw-rings should be located where the inserted long screw will not injure the roots of adjacent maxillary teeth (Fig. 1, B). SURGICAL PROCEDURE The osteotomy is carried out using standard technique with osteotomies of the lateral maxilla, lateral nasal wall, pterygoid plates, and a single osteotomy of the palate slightly to one side of the middle sagittal
DISCUSSION Since the introduction of the concept of distraction osteogenesis for palatal expansion, SARPE has enabled wider expansion of the maxillary dental arch, and this surgically assisted orthodontic treatment has become a standard and important procedure for correction of the narrow maxillary width in adult cases.2 As well as less limitation of elongation of the palatal bone, the generated bone at the anterior maxillary alveolar, which will be used for teeth alignment, may be the reason for the widespread use of SARPE in the orthodontic field. Most common equipment used in SARPE has been the hygienic appliance using Hyrax expansion screws,4 in which all wire flames are soldered to bands that are cemented on the abutment teeth. The expander can be a non-spring-loaded jackscrew. The abutment teeth are generally the first molar and premolars. Therefore, with this equipment, the force for expansion directly acts on these teeth, which will cause tooth tipping, extrusion, periodontal membrane compression, buccal root resorption, fenestration of the buccal cortex, and instability-relapse with the necessity for overcorrection6 and the long periods with fabrication of bands on abutment teeth cause periodontal disease. To solve the problems caused by mechanical stress on teeth, recently a bone-borne appliance for SARPE has been marketed. In both the Transpalatal Distractor (TPDR, Surgi-Tec NV, Burges, Belgium)5-7 and the
e10
Iida et al.
Fig. 2. A case treated by a bone-anchored palatal distractor consisted of a Hyrax type palatal expansion screw and screwrings. A, Intraoral finding before distraction. Bone screws inserted into palatal bone transmucosaly were fixed with the screw-ring by the self-curing acrylic resin to prevent loosening. B, Intraoral finding after distraction. The amount of palatal expansion was 8 mm and the lingual arch orthodontic appliance is placed to maintain the expanded width of the maxillary dental arch and the space between central incisors.
Magdeburg type (KLS Martin, Tuttlingen, Germany),9,10 the screws are used for securing the device to palatal bone. In TPDR, a cylindrical screw for expansion is secured to bone by only 1 screw in each segment and the expansion force acts on a small area. The Magdeburg type consists of a cylindrical screw with 2 miniplates. This device can be secured with palatal bone by 4 screws in each side. The difference of the stability of the distractor influences of the occurrence of obstacles and problems during the treatment. Neyt et al.7 reported the occurrence of loosened distractor in some cases treated by TPDR. The Rotterdam Palatal
OOOOE February 2008
Fig. 3. A case treated by a bone-anchored palatal distractor consists of a Fan-type palatal expansion screw and screwrings. A, Intraoral finding before distraction. B, Intraoral finding after distraction. The amount of palatal expansion was 5 mm at the central incisor level, but the intermolar width was not increased by using this type of distractor.
Distractor (KLS Martin)11 has a unique appearance, which is manufactured simply based on the concept of a car jack. Different from bone-borne appliances, this system has no risk of damage to dental roots and the anterior palatine nerve due to the bone screw insertion, but may have a risk of loosening of the appliance during the consolidation period. Our device has 2 bone anchors by transmucosaly inserting bone screws in each side and may have enough stability during consolidation periods, but the additional adhesion by self-curing resin between the bone screw and screw-ring should be necessary to prevent the loosening of the screw that can be caused by the inflammatory changes of the palatal mucosa around the screws. There are 2 major aims of SARPE: one is producing the space at the anterior portion for alignment and the other is widening the upper dental arch. There may be some differences in the appearance of the dental arch after the consolidation period with the distractor. Pinto
OOOOE Volume 105, Number 2
et al.8 showed the trend that the post expansion of width of the posterior teeth are more than those of the anterior teeth in both rapid palatal expansion and SARPE procedures,8 because of the buccal tilting of the appliancecarrying abutment teeth. To the contrary, the expansion of the anterior potion was greater than that of the molar portion in the case expanded by TPD. Indeed the pterygo-maxillary separation was not performed in their procedure. The characteristic shape of their device, which has a small abutment plate, causes the concentration of expansion forces at a narrow area. Therefore, it is easy to consider the dental arch appearance may be directly influenced by the anchor location as well as the pterygo-maxillary separation. It seems that the Magdeburg type may produce the parallel movement of segments and may maintain the shape during the consolidation period due to the multiple bone anchorages. Our device has 2 anchorages in each side that can widen the segments in parallel but differences of numbers and location of the bone anchorages may influence the appearance of the dental arch after the consolidation period. The fan-style expansion screw was designed and developed to obtain greater expansion in the intercanine width than in the intermolar width.14 Different from other expansion screws, which expand each segment laterally in parallel, this expansion screw allows “fan opening” and is applied for the treatment of cases with anterior maxillary narrowness with normal intermolar width. Among the commercially available bone-anchored expanders, TPD, which has a small area of anchorage in the palatal bone, can effectively expand the anterior maxilla when the distractor is positioned at the anterior maxilla. However, it is clear that the fantype expander can obtain more certain expansion at the anterior maxilla without increasing posterior maxillary width. Therefore, our bone-anchored fan-type screws can more effectively realize the requirement of the orthodontist. In conclusion, the screw-rings of the DynaForm System can be applied to the various orthodontic expansion screws and changes these expansion screws into the bone-anchored distractor. Therefore the concept of a bone-anchored appliance using screw-ring and orthodontic expansion screws may increase the variations of palatal distraction and generalize the transverse maxillary distraction using bone-anchored equipment in these cases.
Iida et al. e11 REFERENCES 1. Bell WH, Epker BN. Surgical-orthodontic expansion of the maxilla. Am J Orthod 1976;70:517-28. 2. Koudstaal MJ, Poort LJ, van der Wal KG, Wolvius EB, PrahlAndersen B, Schulten AJ. Surgically assisted rapid maxillary expansion (SARME): a review of the literature. Int J Oral Maxillofac Surg 2005;34:709-14. 3. Jacobs JD, Bell WH, Williams CE, Kennedy JW. Control of the transverse dimension with surgery and orthodontics. Am J Orthod 1980;77:284-306. 4. Conley RS, Legan HL. Correction of severe vertical maxillary excess with anterior open bite and transverse maxillary deficiency. Angle Orthod 2002;72:265-74. 5. Ramieri GA, Spada MC, Austa M, Bianchi SD, Berrone S. Transverse maxillary distraction with a bone-anchored appliance: dento-periodontal effects and clinical and radiological results. Int J Oral Maxillofac Surg 2005;34:357-63. 6. Mommaerts MY. Transpalatal distraction as a method of maxillary expansion. Br J Oral Maxillofac Surg 1999;37:268-72. 7. Neyt NM, Mommaerts MY, Abeloos JV, De Clercq CA, Neyt LF. Problems, obstacles and complications with transpalatal distraction in non-congenital deformities. J Craniomaxillofac Surg 2002;30:139-43. 8. Pinto PX, Mommaerts MY, Wreakes G, Jacobs W. Immediate postexpansion changes following the use of the transpalatal distractor. J Oral Maxillofac Surg 2001;59:994-1000. 9. Gerlach KL, Zahl C. Transversal palatal expansion using palatal distractor. J Orofac Orthop 2003;64:443-9. 10. Gerlach KL, Zahl C. Surgically assisted rapid palatal expansion using a new distraction device: report of a case with an epimucosal fixation. J Oral Maxillofac Surg 2005;63:711-3. 11. Koudstaal MJ, van der Wal KGH, Wolvius EB, Schlten AJM. The Rotterdam palatal distractor of the new bone-borne device and report of pilot study. Int J Oral Maxillofac Surg 2006;35: 31-5. 12. Guerrero CA, Bell WH, Contasti GI, Rodriguez AM. Mandibular widening by intraoral distraction osteogenesis. Br J Oral Maxillofac Surg. 1997;35:383-92. 13. Guerrero CA, Bell WH, Gonzalez M, Rojas A. Three-Dimensional intraoral distraction osteogenesis. an orthodontic-surgical approach. In: Samchukov ML, Cope JB, Cherkashin AM, editors. Craniofacial distraction osteogenesis. St. Louis: Mosby; 2001. p. 236-46. 14. Doruk C, Bicakci AA, Basciftci FA, Agar U, Babacan H. A comparison of the effects of rapid maxillary expansion and fan-type rapid maxillary expansion on dentofacial structures. Angle Orthod 2004;74:184-94.
Reprint requests: Seiji Iida, DDS, PhD The First Department of Oral and Maxillofacial Surgery Osaka University Graduate School of Dentistry 1-8 Yamadaoka, Suita Osaka 565-0871, Japan [email protected]