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Modular intermaxillary fixation for surgical orthodontics
Modular intermaxillary fixation ”for surgical orthodontics Dr. Wade
Dale B. Wade, D.D.S., MS.,* and Gary L. Racey, D.D.S., MS.** Columbus,
Ohio
With the increased amount of orthognathic surgery being performed by orthodontists und oral-maxillofacial surgeons, more ejjicient treatment techniques are being perfected. Modular intermaxillary jixution has been developed to help the orthodontist prepure his patient for surgery und provide the surgeon with the stable fixation needed for proper healing. It is ef/icient, saves chair time, is comfortable and esthetic, and is well accepted by patients. Modular intermaxillary fixation has been evaluated for more than a yeur, with good results in correcting mandibular skeletal dysplasias in all three plunes of space.
Key words: Surgical orthodontics, modular intermaxillary
fixation
W
ith the increased number of patients requiring surgical-orthodontic treatment, the need for an effective, efficient, and time-saving method of intermaxillary fixation has become apparent. The orthodontist now spends a great deal of chair time preparing patients for conventional intermaxillary fixation. If brass or steel vertical posts are to be soldered to the base arch, the arch has to be marked, removed, soldered, polished, and retied into the brackets. Hooks that are tied onto the brackets, as well as crimp-on hooks and arch bars that are placed over the base arch, have also been employed. These methods all require considerable chair time, and the resultant fixation appliance is bulky and may be difficult for the patient to keep clean. The use of an elastic module to hold a standard arch wire in the brackets and also provide intermaxillary fixation was considered (1) to reduce chair time needed to prepare patients for surgery and (2) to provide a less bulky fixation method. Subjects and methods Case 1 Modular intermaxillary fixation was first evaluated on a male patient with mandibular retrognathism and Class II malocclusion, who had already undergone a sagittal split of both rami and an advancement of the mandible. His original intermaxillary fixation used soldered brass vertical posts and heavy elastic traction (Fig. 1). After 3 weeks of this, he was switched over to the modular intermaxillary fixation (Fig. 2). Following 1 week with the modules the patient was questioned about any subjective differences between the two types of fixation. He stated that the modules provided slightly more traction than the heavy elastics and that they were much more comfortable. Frownthe College of Dentistry, The Ohio State University. There was no financial support for this study, and the authorshave no personalinterest in the products or services mentioned in the article. *Assistant Clinical Professor of Orthodontics. **Associate Professor and Director of Postgraduate Training, Oral and Maxillofacial Surgery. 0002~9416/80/060613+07$00.70/0
0 1980 The C. V. Mosby Co.
613
614
Wude and Rtmy
Fig. 1. Conventional elastic traction.
intermaxillary
fixation with soldered 0.032 inch brass vertical posts and heavy
Fig. 2. The patient shown in Fig. 1 was changed to modular intermaxillary fixation. Clear modules were tried on the anterior segment but were found to be more difficult to work with than the gray KX-1 modules.
He appreciated the improved esthetic appearance and said that his teeth were much easier to keep clean. The modules were used for an additional 3 weeks to complete the period of intermaxillary fixation. They did not break or come off during the fixation period. Case
2
This female patient had mandibular prognathism and a Class III malocclusion. At the comnletion of surgery the modules were placed for intermaxillary fixation. An advantage that became
Modular
intermaxillary
jixation
615
Fig. 3. These modules have been in place for 4 weeks. Note how easy they are to keep clean. This case involved a Class Ill surgical correction, so the buccal modules are placed in a Class Ill direction.
apparent was that the modules could be placed to produce traction in a Class III direction (Fig. 3) or in a Class II direction (Fig. 5). It is necessary to have the connector of the module come off the mesiogingival comer of the mandibular brackets for Class III patients and off the distogingival comer for Class II patients. As the modules are stretched to the maxillary brackets, they are locked around the gingival wing of the bracket. Modules then serve two purposes: They hold the arch wire in the bracket, and they provide adequate intermaxillary fixation for treatment of skeletal dysplasias. This patient also had no problem with fatigue of the modules, breakage, or loss during the period of fixation.
Case 3 This female patient with mandibular retrognathism and apertognathia and a Class II malocclusion required mandibular advancement and counterclockwise rotation to improve her skeletal discrepancy. It was determined that there would be less movement and trauma of the mandible if the modules were already in place on the mandibular brackets prior to surgical intervention. This would also save time in the operating room. The modules were placed in Class II position on the mandibular brackets 3 days prior to surgery, placement requiring approximately 5 minutes of chair time (Fig. 4). At the time of surgery the ties were removed from the maxillary brackets and the modules were hfted up and placed on the maxillary brackets. This required only a few minutes in the operating room (Fig. 5).
Results Certain advantages of modular intermaxillary fixation have become apparent: 1. The modules and brackets are easier to keep clean than the standard elastic fixation appliances. 2. The patients appreciate the comfort, esthetics, and lack of bulk of the modular fixation. 3. It is possible to control the direction of traction of the modules by altering
Fig. 4. Modules in place prior to surgery. The modules will pull off unless they are lifted to the maxillary arch from either the mesiogingival or the distogingival corner of the mandibular brackets. This acts to lock them on the mandibular brackets.
placement of the module on the brackets according to the type of surgical procedure that is to be performed. 4. The amount of intermaxillary traction can be varied, depending upon the method and site of attachment. 5. With the teeth in occlusion, the modules can be adjusted to provide passive intermaxillary fixation. Traction becomes progressively more active as the teeth are separated or moved. 6. The orthodontist and the patient save chair time, since soldered posts, hooks, or separate ties are not necessary. 7. The orthodontist does not run the risk of annealing the arch wires with soldering. 8. Modular fixation permits the use of finishing arch wires into the second molars with buccal tubes on the first molars. 9. There is no need to change arch wires prior to or following surgery. 10. The gingiva stays healthier, since there are no vertical hooks or posts. 11. The modules can be attached to the mandibular arch preoperatively to save time and mandibular manipulation during surgery. 12. It is easy to stop the intermaxillary fixation by merely cutting the modules in the middle, as seen in Fig. 6. 13. The modules can be used in conjunction with intraosseous fixation, as seen in Figs. 7 and 8. 14. Although not recommended, it is possible to use the modules in conjunction with round arch wires, as seen in Fig. 9. Discussion The modules are most effective with twin edgewise brackets. Hooks still need to be attached to the molar bands or buccal tubes if fixation is requited in these areas. The
Volume 77 Number 6
Modular
intermaxillary
jixation
617
Fig. 5. The same patient as in Fig. 4 at the time of surgery, showing the intermaxillary fixation with the modules in a Class II direction. The mandibular lateral incisors were not used in the fixation but could have been if the surgeon had deemed it necessary.
Fig. 6. It is not necessary to remove the modules at the completion of fixation, The surgeon can merely cut away the segment of the module between the two ends. Hooks are then tied on where indicated for light “training elastics.”
oral-maxillofacial surgeon should receive instruction and practice in placing the modules on a typodont prior to surgery, so that he will be familiar and experienced with the procedure. The surgeon should count the number of modules in place on mandibular brackets prior to the operation, so that none are inadvertently removed or lost during surgery. Also, the orthodontist and the oral-maxillofacial surgeon must coordinate their treatment, so that some type of “guiding elastics” or light intermaxillary elastics can be placed following removal of the modular fixation. If a thick interocclusal splint is to be used, the modules would probably not be
Fig. 7. A patient prior to surgery for a maxillary impaction and mandibular advancement with counterclockwise rotation. Note that the modules are in place on the mandibular brackets and in position for Class II traction.
Fig. 8. The patient shown in Fig. 7 at the time of surgery. Note the interdental modular fixation as well as the intraosseous wire fixation of the maxilla to the maxillary arch wire. Since the connector comes off the incisal portion of both brackets, there is less tension on the modules.
indicated. They would deliver more traction than necessary, since the interbracket distance would have been increased. The modules that have seemed most appropriate for proper fixation are the Unitek KX-1 modules. They are gray and seem to have the best length for the usual interbracket distance. The size of the lumen of the module can be increased with a diamond or green stone to aid in placement of the module on the brackets. Certain deep-bite Class II surgical patients have had arches that are difficult to level completely prior to surgery. If there had been good tripoding and stability of the teeth, even though the second premolars and first molars were not completely in occlusion, the surgery was performed without use of a splint. With no splint present and with the use of elastic traction, orthodontic leveling continued during the intermaxillary fixation and the mild dental open-bite in the buccal segments was eliminated.
Volume 77 Number 6
Modular intermaxillar?, @cation
619
Fig. 9. This skeletal Class III patient was moving out of the state but wanted her surgical treatment done before she lefl. Rectangular arch wires had not even been placed yet. This shows that modular intermaxillary fixation is possible on round wire.
Conclusion The use of modular intermaxillary fixation reduces chair time and has met with excellent acceptance by patients. Placing the modules on the mandibular arch prior to surgery gives the patient a chance to adjust to their size and shape and reduces operating room time for the surgeon. Certain additional advantages have been determined, and the modules have been demonstrated to work well in patients with Class III and Class II skeletal dysplasias, apertognathia, and asymmetries of the mandible requiring surgical treatment. The use of modular elastics for maxillary orthognathic surgery is currently being assessed.
Dale B. Wade, D.D.S., MS.,* and Gary L. Racey, D.D.S., MS.** Columbus,
Ohio
With the increased amount of orthognathic surgery being performed by orthodontists und oral-maxillofacial surgeons, more ejjicient treatment techniques are being perfected. Modular intermaxillary jixution has been developed to help the orthodontist prepure his patient for surgery und provide the surgeon with the stable fixation needed for proper healing. It is ef/icient, saves chair time, is comfortable and esthetic, and is well accepted by patients. Modular intermaxillary fixation has been evaluated for more than a yeur, with good results in correcting mandibular skeletal dysplasias in all three plunes of space.
Key words: Surgical orthodontics, modular intermaxillary
fixation
W
ith the increased number of patients requiring surgical-orthodontic treatment, the need for an effective, efficient, and time-saving method of intermaxillary fixation has become apparent. The orthodontist now spends a great deal of chair time preparing patients for conventional intermaxillary fixation. If brass or steel vertical posts are to be soldered to the base arch, the arch has to be marked, removed, soldered, polished, and retied into the brackets. Hooks that are tied onto the brackets, as well as crimp-on hooks and arch bars that are placed over the base arch, have also been employed. These methods all require considerable chair time, and the resultant fixation appliance is bulky and may be difficult for the patient to keep clean. The use of an elastic module to hold a standard arch wire in the brackets and also provide intermaxillary fixation was considered (1) to reduce chair time needed to prepare patients for surgery and (2) to provide a less bulky fixation method. Subjects and methods Case 1 Modular intermaxillary fixation was first evaluated on a male patient with mandibular retrognathism and Class II malocclusion, who had already undergone a sagittal split of both rami and an advancement of the mandible. His original intermaxillary fixation used soldered brass vertical posts and heavy elastic traction (Fig. 1). After 3 weeks of this, he was switched over to the modular intermaxillary fixation (Fig. 2). Following 1 week with the modules the patient was questioned about any subjective differences between the two types of fixation. He stated that the modules provided slightly more traction than the heavy elastics and that they were much more comfortable. Frownthe College of Dentistry, The Ohio State University. There was no financial support for this study, and the authorshave no personalinterest in the products or services mentioned in the article. *Assistant Clinical Professor of Orthodontics. **Associate Professor and Director of Postgraduate Training, Oral and Maxillofacial Surgery. 0002~9416/80/060613+07$00.70/0
0 1980 The C. V. Mosby Co.
613
614
Wude and Rtmy
Fig. 1. Conventional elastic traction.
intermaxillary
fixation with soldered 0.032 inch brass vertical posts and heavy
Fig. 2. The patient shown in Fig. 1 was changed to modular intermaxillary fixation. Clear modules were tried on the anterior segment but were found to be more difficult to work with than the gray KX-1 modules.
He appreciated the improved esthetic appearance and said that his teeth were much easier to keep clean. The modules were used for an additional 3 weeks to complete the period of intermaxillary fixation. They did not break or come off during the fixation period. Case
2
This female patient had mandibular prognathism and a Class III malocclusion. At the comnletion of surgery the modules were placed for intermaxillary fixation. An advantage that became
Modular
intermaxillary
jixation
615
Fig. 3. These modules have been in place for 4 weeks. Note how easy they are to keep clean. This case involved a Class Ill surgical correction, so the buccal modules are placed in a Class Ill direction.
apparent was that the modules could be placed to produce traction in a Class III direction (Fig. 3) or in a Class II direction (Fig. 5). It is necessary to have the connector of the module come off the mesiogingival comer of the mandibular brackets for Class III patients and off the distogingival comer for Class II patients. As the modules are stretched to the maxillary brackets, they are locked around the gingival wing of the bracket. Modules then serve two purposes: They hold the arch wire in the bracket, and they provide adequate intermaxillary fixation for treatment of skeletal dysplasias. This patient also had no problem with fatigue of the modules, breakage, or loss during the period of fixation.
Case 3 This female patient with mandibular retrognathism and apertognathia and a Class II malocclusion required mandibular advancement and counterclockwise rotation to improve her skeletal discrepancy. It was determined that there would be less movement and trauma of the mandible if the modules were already in place on the mandibular brackets prior to surgical intervention. This would also save time in the operating room. The modules were placed in Class II position on the mandibular brackets 3 days prior to surgery, placement requiring approximately 5 minutes of chair time (Fig. 4). At the time of surgery the ties were removed from the maxillary brackets and the modules were hfted up and placed on the maxillary brackets. This required only a few minutes in the operating room (Fig. 5).
Results Certain advantages of modular intermaxillary fixation have become apparent: 1. The modules and brackets are easier to keep clean than the standard elastic fixation appliances. 2. The patients appreciate the comfort, esthetics, and lack of bulk of the modular fixation. 3. It is possible to control the direction of traction of the modules by altering
Fig. 4. Modules in place prior to surgery. The modules will pull off unless they are lifted to the maxillary arch from either the mesiogingival or the distogingival corner of the mandibular brackets. This acts to lock them on the mandibular brackets.
placement of the module on the brackets according to the type of surgical procedure that is to be performed. 4. The amount of intermaxillary traction can be varied, depending upon the method and site of attachment. 5. With the teeth in occlusion, the modules can be adjusted to provide passive intermaxillary fixation. Traction becomes progressively more active as the teeth are separated or moved. 6. The orthodontist and the patient save chair time, since soldered posts, hooks, or separate ties are not necessary. 7. The orthodontist does not run the risk of annealing the arch wires with soldering. 8. Modular fixation permits the use of finishing arch wires into the second molars with buccal tubes on the first molars. 9. There is no need to change arch wires prior to or following surgery. 10. The gingiva stays healthier, since there are no vertical hooks or posts. 11. The modules can be attached to the mandibular arch preoperatively to save time and mandibular manipulation during surgery. 12. It is easy to stop the intermaxillary fixation by merely cutting the modules in the middle, as seen in Fig. 6. 13. The modules can be used in conjunction with intraosseous fixation, as seen in Figs. 7 and 8. 14. Although not recommended, it is possible to use the modules in conjunction with round arch wires, as seen in Fig. 9. Discussion The modules are most effective with twin edgewise brackets. Hooks still need to be attached to the molar bands or buccal tubes if fixation is requited in these areas. The
Volume 77 Number 6
Modular
intermaxillary
jixation
617
Fig. 5. The same patient as in Fig. 4 at the time of surgery, showing the intermaxillary fixation with the modules in a Class II direction. The mandibular lateral incisors were not used in the fixation but could have been if the surgeon had deemed it necessary.
Fig. 6. It is not necessary to remove the modules at the completion of fixation, The surgeon can merely cut away the segment of the module between the two ends. Hooks are then tied on where indicated for light “training elastics.”
oral-maxillofacial surgeon should receive instruction and practice in placing the modules on a typodont prior to surgery, so that he will be familiar and experienced with the procedure. The surgeon should count the number of modules in place on mandibular brackets prior to the operation, so that none are inadvertently removed or lost during surgery. Also, the orthodontist and the oral-maxillofacial surgeon must coordinate their treatment, so that some type of “guiding elastics” or light intermaxillary elastics can be placed following removal of the modular fixation. If a thick interocclusal splint is to be used, the modules would probably not be
Fig. 7. A patient prior to surgery for a maxillary impaction and mandibular advancement with counterclockwise rotation. Note that the modules are in place on the mandibular brackets and in position for Class II traction.
Fig. 8. The patient shown in Fig. 7 at the time of surgery. Note the interdental modular fixation as well as the intraosseous wire fixation of the maxilla to the maxillary arch wire. Since the connector comes off the incisal portion of both brackets, there is less tension on the modules.
indicated. They would deliver more traction than necessary, since the interbracket distance would have been increased. The modules that have seemed most appropriate for proper fixation are the Unitek KX-1 modules. They are gray and seem to have the best length for the usual interbracket distance. The size of the lumen of the module can be increased with a diamond or green stone to aid in placement of the module on the brackets. Certain deep-bite Class II surgical patients have had arches that are difficult to level completely prior to surgery. If there had been good tripoding and stability of the teeth, even though the second premolars and first molars were not completely in occlusion, the surgery was performed without use of a splint. With no splint present and with the use of elastic traction, orthodontic leveling continued during the intermaxillary fixation and the mild dental open-bite in the buccal segments was eliminated.
Volume 77 Number 6
Modular intermaxillar?, @cation
619
Fig. 9. This skeletal Class III patient was moving out of the state but wanted her surgical treatment done before she lefl. Rectangular arch wires had not even been placed yet. This shows that modular intermaxillary fixation is possible on round wire.
Conclusion The use of modular intermaxillary fixation reduces chair time and has met with excellent acceptance by patients. Placing the modules on the mandibular arch prior to surgery gives the patient a chance to adjust to their size and shape and reduces operating room time for the surgeon. Certain additional advantages have been determined, and the modules have been demonstrated to work well in patients with Class III and Class II skeletal dysplasias, apertognathia, and asymmetries of the mandible requiring surgical treatment. The use of modular elastics for maxillary orthognathic surgery is currently being assessed.