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Repositioning of the gingival margin by extrusion
CASE REPORT
Repositioning of the gingival margin by extrusion Siew Han Chay, BDS, MOrth, MOrth RCS (Edin),a and A. Bakr M. Rabie, Cert.Ortho, MS, PhDb Singapore and Hong Kong In this case report, orthodontic intervention was used to move the gingival margin of a maxillary canine incisally by almost 9 mm to mimic a lateral incisor. Increasing the thickness of the labial plate of bone of the canine and subsequently increasing the thickness of the attached gingiva before extrusion prevented gingival recession at a later stage. In many situations, orthodontic treatment can achieve results that could not be attained by restorations and other means of cosmetic dentistry, especially when dealing with gingival margins and gingival height. A step-by-step approach to achieving these treatment objectives is described. (Am J Orthod Dentofacial Orthop 2002;122:95–102)
I
n today’s world, when many people pursue excellent cosmetic enhancement, dentists have a demanding job trying to keep up with their patients’ esthetic expectations. Many products are at their disposal to accomplish this aim: crowns, veneers, direct adhesive esthetic restorations, implants, and bleaching.1-6 However, an important option that should be included but is often omitted because of lack of knowledge is orthodontic intervention. In many situations, orthodontic treatment can achieve results that could not be attained by restorations and other means of cosmetic dentistry, especially when dealing with gingival margins and gingival heights. In this case report, orthodontic treatment to move the gingival margins incisally by almost 9 mm is presented, and the step-bystep approach to achieving the treatment objectives is described. HISTORY AND DIAGNOSIS
A healthy 34-year-old Indian woman was examined in the graduate orthodontic clinic at Hong Kong University. She complained about a long tooth and crowding (Figs 1 and 2). Her maxillary left lateral incisor had been extracted previously, and the canine was moved into place with a removable appliance. The dentist tried to substitute the canine for the lateral incisor, but the clinical crown was a Assistant professor of orthodontics, Faculty of Dentistry, University of Singapore, Singapore. b Associate professor of orthodontics, Faculty of Dentistry, University of Hong Kong, Hong Kong, SAR. Reprint requests to: Dr A. Bakr M. Rabie, Orthodontics, Faculty of Dentistry, Prince Philip Dental Hospital, 34 Hospital Rd, Hong Kong, SAR; e-mail, [email protected]. Submitted, May 2001; revised and accepted, September 2001. Copyright © 2002 by the American Association of Orthodontists. 0889-5406/2002/$35.00 ⫹ 0 8/4/122397 doi:10.1067/mod.2002.122397
too long to create an acceptable esthetic result. Furthermore, the gingival height and a bony depression caused by the canine eminence were also major concerns for her. The patient had a straight lateral profile with a Class I malocclusion. Her incisors were Class III with an overjet of 0.5 mm and a minimal overbite of 1.5 mm. The first premolars were positioned in buccal crossbite. Severe crowding of 12 mm was present in the mandibular arch. Both the maxillary right canine and the maxillary left lateral incisor were missing. Her mandibular dental midline deviated to the right by 0.5 mm, but the maxillary dental midline coincided with the facial midline (Fig 3). The orthopantomogram revealed bony defects in the areas of the missing teeth (Fig 4). The lateral cephalogram and tracing showed a skeletal Class I relationship with slight retroclination of the maxillary and mandibular incisors (Figs 5 and 6). Both upper and lower lips were retrusive. TREATMENT OBJECTIVES
The dentobasal objectives were to normalize overjet and overbite and eliminate the crossbite. The dentoalveolar objectives were to extrude the maxillary left canine to mimic a lateral incisor, to level the gingival height at the maxillary left lateral site, to eliminate and improve the bony depression at the mesial of the maxillary left canine, to correct the midline, to align the teeth, and to coordinate the arch forms. TREATMENT ALTERNATIVES Option 1
In the mandibular arch, the first treatment option included extracting the right and left first premolars and using a fixed appliance to level and align the teeth; maximum anchorage would be needed. In the maxillary 95
96 Chay and Rabie
American Journal of Orthodontics and Dentofacial Orthopedics July 2002
Fig 1. Pretreatment photos of 34-year-old Indian woman with maxillary left canine replacing missing lateral incisor. Profile photo shows straight lateral facial profile.
Fig 2. Intraoral photos show high gingival margin of maxillary left canine with composite buildup to mimic lateral incisor and bony depression on mesial of tooth.
Fig 3. Pretreatment study models.
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American Journal of Orthodontics and Dentofacial Orthopedics Volume 122, Number 1
Fig 4. Pretreatment panoramic radiograph shows bony defects at areas of missing maxillary right canine and maxillary left lateral incisor.
Fig 5. Lateral cephalogram reveals skeletal Class I relationship with slight retroclination of incisors.
arch, a fixed appliance would be used to level and align the teeth. Special consideration for the maxillary left canine would be needed: (1) a fixed appliance would be used to torque the root palatally followed by extrusion and alignment, (2) the root would be moved mesially to reduce the bony depression, and (3) the maxillary left canine would substitute for the lateral incisor. Option 2
Under option 3, the mandibular first premolars would be extracted. In the maxillary arch, the left first premolar would be extracted, and the left canine would be moved distally into a Class I relationship, with an open space for the left lateral incisor replacement. This plan had several disadvantages: 1. Option 2 required the extraction of another tooth in the maxillary arch, and the patient would need a
Fig 6. Pretreatment cephalometric tracing.
prosthetic replacement. The prosthetic replacement could require ridge augmentation because of the narrow ridge at the lateral incisor site. This would cause the loss of tooth structure and be an additional expense for the patient. 2. The maxillary right canine was extracted before treatment, and the first right premolar could be used as a canine. This could produce a tooth size discrepancy because the sizes of a premolar and a canine are different; this could cause a midline shift. Option 1 offered symmetry and avoided space closure mechanics. 3. Space closure mechanics in option 2 would require more force on the root of the canine; that could be detrimental to the health of the gingival margins. The gingiva at the canine site showed signs of recession before treatment. Heavier forces are required to produce a counterbalancing moment to control the axial inclination of the canine because the root apex was positioned mesially. Extrusion, on the other hand, requires less force, and the distance of tooth movement is considerably shorter. 4. Option 2 failed to address the bony depression mesial to the canine. This bony depression could become worse as a result of moving the canine distally. Option 1 addressed this point by moving the root of the canine mesially. Because of these disadvantages, option 1 was selected. TREATMENT PROGRESS
The patient’s oral hygiene was monitored regularly throughout treatment. She was referred for extraction of the mandibular right and left first premolars as planned. Initially, only the mandibular arch was banded and bonded, bypassing the anterior teeth to avoid their
98 Chay and Rabie
American Journal of Orthodontics and Dentofacial Orthopedics July 2002
Fig 7. A, Distally positioned bracket on maxillary left canine and auxiliary 0.016-in NiTi wire to level and align it. B, Palatal root torque to maxillary left canine using auxiliary 0.017 ⫻ 0.025–in TMA archwire. C, Extrusion of maxillary left canine with 0.016-in stainless steel archwire with 2 boot loops (butterfly loop); composite buildup gradually removed from incisal tip. D, Maxillary left canine extruded. Note closed boot loops, now passive. E, Bracket on maxillary left canine repositioned. F, Composite buildup on mesioincisal angle of maxillary left canine to mimic lateral incisor.
proclination. A 0.022–in preadjusted slot system and triple tube bands in the maxillary arch and double tube bands in the mandibular arch were used. After initial leveling and aligning with a 0.016 –in NiTi wire, a segmental 0.017 ⫻ 0.025–in titanium molybdenum alloy (TMA) wire with closing loops was used to retract the canines into the extraction spaces. Spontaneous alignment of the mandibular anterior teeth could be seen as space was created during distal movement of the canines. After 3 months, the mandibular incisors and the maxillary dentition were bonded. The bracket on the maxillary left canine was tilted distally to help upright the root. Leveling and aligning were carried out with an auxiliary 0.016 –in NiTi wire placed from the auxiliary tube on the band of the maxillary right molar to the bracket on the maxillary left canine to the auxiliary tube on maxillary left molar (Fig 7, A). The auxiliary wire was then switched to a 0.017 ⫻ 0.025–in TMA wire with palatal root torque to move the roots palatally to increase the thickness of the labial plate of bone before the extrusion (Fig 7, B). Extrusion of the maxillary left canine was carried out with 0.016 –in stainless steel archwire with 2 boot loops (butterfly loop) (Fig 7, C). This loop design is versatile and flexible. Height adjustment of the tooth was easily performed, and activation was simple with no fear of running out of space. As extrusion pro-
ceeded, the composite restoration was gradually removed from the incisal tip of the canine. After sufficient extrusion (Fig 7, D), the bracket was repositioned properly (Fig 7, E), and further alignment was carried out. Meanwhile, the mandibular extraction spaces were closed with closing loops by using a 0.017 ⫻ 0.025–in TMA wire with lingual root torque on the incisors. Both the maxillary and mandibular archwires were changed progressively, with 0.019 ⫻ 0.025–in TMA wire for optimal torque control. Finishing and detailing were completed with 0.017 ⫻ 0.025–in TMA wires. Buccal root torque was increased on teeth numbers 14 and 24 to mimic the prominence of canines. An artistic bend was added to the wire at tooth number 41 to close the open gingival embrasure on the distal. A composite restoration was placed on the mesioincisal angle of the maxillary left canine to mimic a lateral incisor (Fig 7, F). After 28 months of active treatment, the patient was debonded, and a mandibular fixed retainer and a maxillary modified Hawley retainer were inserted (Figs 8-14). RESULTS
All treatment objectives were achieved, and the patient’s esthetic demands were accomplished. The height of the gingival margin of the maxillary left canine was corrected and is nearly at the same level as the contralateral incisor. The clinical crown length of the
American Journal of Orthodontics and Dentofacial Orthopedics Volume 122, Number 1
Fig 8. Posttreatment photos, after 28 months of orthodontic treatment.
Fig 9. Posttreatment intraoral photographs.
Fig 10. Posttreatment study models.
Chay and Rabie 99
100 Chay and Rabie
Fig 11. Posttreatment panoramic radiograph. Note reduction of bony defects on sites of missing maxillary right canine and maxillary left lateral incisor.
American Journal of Orthodontics and Dentofacial Orthopedics July 2002
Fig 13. Postreatment cephalometric tracing.
Fig 14. Superimposed tracings. Fig 12. Posttreatment lateral cephalogram showing normal proclination of incisors.
maxillary left canine was greatly reduced with extrusion and esthetic dentistry to mimic a lateral incisor (Fig 15). The bony depression on the mesial of the maxillary left canine was reduced substantially as the root was moved mesially. The overbite and overjet were improved, and the crossbite and the midlines were corrected. The Class I molar relationship was maintained. Cephalometric analysis of posttreatment radiographs showed proclination of the maxillary incisors (Figs 12 and 13). The lower face height increased slightly, and the mandibular plane angle decreased slightly. Superimposition of pretreatment and posttreatment radiographs showed good control during space closure, and the vertical relationship between the maxillary and mandibular molars was unchanged (Fig 14). The maxillary incisors were torqued palatally, and the mandibular incisors were retracted.
DISCUSSION AND CONCLUSIONS
The role of the orthodontist in improving gingival levels is often overlooked. Innovative orthodontic concepts should be used to enhance biologic structure as well as the esthetics of the supporting tissues. In this patient, the labial gingival margin of the maxillary left canine was moved almost 9 mm incisally through orthodontic extrusion. Extreme care was given to the gingival tissues through prudent planning of the orthodontic treatment. A periodontal evaluation in an adult orthodontic patient must include an assessment of the level and the condition of the attached gingiva—the part of the gingiva that is tightly bound to the underlying bone.7 Earlier animal experiments suggested that the thickness of the gingiva, rather than its surface qualities, could be the key factor that influences the occurrence of recession.8 Proclination of incisors in some patients may be followed by thinning of the alveolar bone, leading to thinning of the attached gingiva. These patients are at higher risk for gingival
Chay and Rabie 101
American Journal of Orthodontics and Dentofacial Orthopedics Volume 122, Number 1
Fig 15. Note gingival level and composite buildup of maxillary left canine to mimic lateral incisor.
recession and loss of attachment.9 Therefore, the gingival condition must receive major attention when planning the orthodontic treatment. In the present case, the attached gingiva was very thin because of the canine prominence, and the gingival margin was 9 mm higher than that of the adjacent teeth (Fig 2). The width of the attached gingiva was 2 mm, considerably less than that of the adjacent teeth. The width of the attached gingiva is measured as the amount of keratinized gingiva between the depth of periodontal probing and the beginning of the alveolar mucosa.7 Therefore, in planning the treatment for this patient, protective measures were taken to increase the thickness of the labial plate of bone and subsequently the thickness of the attached gingiva before extruding the canine. Determining the sequence of this patient’s orthodontic treatment was based on understanding the relationship between orthodontic tooth movement and the different biologic processes that would take place. The first step in the orthodontic treatment was palatal root torque of the maxillary left canine. As the root moved palatally, the periodontal ligament was stretched on the labial surface, leading to bone deposition at the crest of the alveolus.7 The increase in the thickness of the labial plate of bone produced an increase in the thickness of the attached gingiva. It is believed that, for some adult patients, gingival grafting before orthodontic treatment prevents gingival recession.11,12 Increasing the thickness rather than the width of the attached gingiva probably produces this protective effect. Increasing the thickness of the labial plate of bone through palatal root torque could also increase the thickness of the attached gingiva and therefore could also prevent gingival recession. Increasing the thickness of the labial plate of bone may render a healthier
attachment around the tooth and ensure that both the bone and the gingiva follow the tooth during extrusion. The application of palatal torque was made possible on the second visit, before leveling and alignment were completed. The rectangular wire was placed in the auxiliary tubes of the first molars, bypassing all teeth until it was tied to the bracket of the maxillary left canine (Fig 7, B). Four months later, the attached gingiva looked healthier (Fig 7, C), and the prominence of the root was less apparent. The width of the attached gingiva increased as the palatal root torque was improved. This was the indication to begin gradual extrusion of the maxillary canine. As the canine was extruded, the gingiva followed (Fig 7, D). The composite restoration on the incisal edge was removed gradually to provide enough space for the extrusion. After the extrusion was completed, a lateral incisor bracket was placed on the maxillary left canine in an ideal position, and the root was moved mesially to reduce the bony depression. Because the root of the maxillary left canine was moved palatally, it was safe to move the root mesially. This movement was accomplished with a gable bend in the wire, and the mesial of the tooth was extruded and the distal intruded (Fig 7, E). The patient was then referred to a dentist to restore the maxillary left canine with composite to simulate the appearance of a lateral incisor (Fig 7, F). Again, the sequence of treatment ensured a successful result, because the root of the canine was tipped mesially only after the root was moved palatally. Therefore, if the attached gingiva appears thin and vulnerable and there is a chance of gingival recession with orthodontic tooth movement, increasing the thickness of bone through orthodontic intervention may be a way to create healthier attached gingiva before tooth movement.
REFERENCES 1. Dietschi D, Dietschi JM. Current developments in composite materials and techniques. Pract Periodontics Aesthet Dent 1996; 8:603-13. 2. Touati B. The evolution of aesthetic restorative materials for inlays and onlays: a review. Pract Periodontics Aesthet Dent 1996;8:657-66. 3. Morig G. Aesthetic all-ceramic restorations: a philosophic and clinical review. Prac Periodontics Aesthet Dent 1996;8:741-9. 4. Albers HE. Porcelain veneers. Adept Report 1990;1:17-28. 5. Haywood VB. Bleaching of vital and nonvital teeth: review. Curr Opinion Dent 1992;2:142-9. 6. Whitters CJ, Strang R, Brown D, Clarke RL, Curtis RV, Hatton PV, et al. Dental materials: 1997 literature review. J Dent 1999;27:401-35. 7. Lindhe J, Karring T. Anatomy of the periodontium. In: Lindhe J, Karring T, Lang NP, editors. Clinical periodontology and implant dentistry. Copenhagen: Munksgaard; 1997. p. 23.
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8. Wennstrom JL, Lindhe J, Sinclair F, Thilander B. Some periodontal tissue reactions to orthodontic tooth movement in monkeys. J Clin Periodontol 1987;14:121-9. 9. Proffit WR. Special considerations in comprehensive treatment of adults. In: Proffit WR, Fields HW, Ackerman JL, Sinclair PM, Thomas PM, Tulloch JFC, editors. Contemporary orthodontics. St Louis: Mosby Year Book; 1993. p. 594.
American Journal of Orthodontics and Dentofacial Orthopedics July 2002
10. Mitchell L. Anchorage, tooth movement and retention. In: Mitchell L, editor. An introduction to orthodontics. New York: Oxford; 1996. p. 146-7. 11. Boyd RL. Mucogingival considerations and their relationship to orthodontics. J Periodontol 1978;49:67-76. 12. Hall WB. The current status of mucogingival problems and their therapy. J Periodontol 1981;52:569-75.
Repositioning of the gingival margin by extrusion Siew Han Chay, BDS, MOrth, MOrth RCS (Edin),a and A. Bakr M. Rabie, Cert.Ortho, MS, PhDb Singapore and Hong Kong In this case report, orthodontic intervention was used to move the gingival margin of a maxillary canine incisally by almost 9 mm to mimic a lateral incisor. Increasing the thickness of the labial plate of bone of the canine and subsequently increasing the thickness of the attached gingiva before extrusion prevented gingival recession at a later stage. In many situations, orthodontic treatment can achieve results that could not be attained by restorations and other means of cosmetic dentistry, especially when dealing with gingival margins and gingival height. A step-by-step approach to achieving these treatment objectives is described. (Am J Orthod Dentofacial Orthop 2002;122:95–102)
I
n today’s world, when many people pursue excellent cosmetic enhancement, dentists have a demanding job trying to keep up with their patients’ esthetic expectations. Many products are at their disposal to accomplish this aim: crowns, veneers, direct adhesive esthetic restorations, implants, and bleaching.1-6 However, an important option that should be included but is often omitted because of lack of knowledge is orthodontic intervention. In many situations, orthodontic treatment can achieve results that could not be attained by restorations and other means of cosmetic dentistry, especially when dealing with gingival margins and gingival heights. In this case report, orthodontic treatment to move the gingival margins incisally by almost 9 mm is presented, and the step-bystep approach to achieving the treatment objectives is described. HISTORY AND DIAGNOSIS
A healthy 34-year-old Indian woman was examined in the graduate orthodontic clinic at Hong Kong University. She complained about a long tooth and crowding (Figs 1 and 2). Her maxillary left lateral incisor had been extracted previously, and the canine was moved into place with a removable appliance. The dentist tried to substitute the canine for the lateral incisor, but the clinical crown was a Assistant professor of orthodontics, Faculty of Dentistry, University of Singapore, Singapore. b Associate professor of orthodontics, Faculty of Dentistry, University of Hong Kong, Hong Kong, SAR. Reprint requests to: Dr A. Bakr M. Rabie, Orthodontics, Faculty of Dentistry, Prince Philip Dental Hospital, 34 Hospital Rd, Hong Kong, SAR; e-mail, [email protected]. Submitted, May 2001; revised and accepted, September 2001. Copyright © 2002 by the American Association of Orthodontists. 0889-5406/2002/$35.00 ⫹ 0 8/4/122397 doi:10.1067/mod.2002.122397
too long to create an acceptable esthetic result. Furthermore, the gingival height and a bony depression caused by the canine eminence were also major concerns for her. The patient had a straight lateral profile with a Class I malocclusion. Her incisors were Class III with an overjet of 0.5 mm and a minimal overbite of 1.5 mm. The first premolars were positioned in buccal crossbite. Severe crowding of 12 mm was present in the mandibular arch. Both the maxillary right canine and the maxillary left lateral incisor were missing. Her mandibular dental midline deviated to the right by 0.5 mm, but the maxillary dental midline coincided with the facial midline (Fig 3). The orthopantomogram revealed bony defects in the areas of the missing teeth (Fig 4). The lateral cephalogram and tracing showed a skeletal Class I relationship with slight retroclination of the maxillary and mandibular incisors (Figs 5 and 6). Both upper and lower lips were retrusive. TREATMENT OBJECTIVES
The dentobasal objectives were to normalize overjet and overbite and eliminate the crossbite. The dentoalveolar objectives were to extrude the maxillary left canine to mimic a lateral incisor, to level the gingival height at the maxillary left lateral site, to eliminate and improve the bony depression at the mesial of the maxillary left canine, to correct the midline, to align the teeth, and to coordinate the arch forms. TREATMENT ALTERNATIVES Option 1
In the mandibular arch, the first treatment option included extracting the right and left first premolars and using a fixed appliance to level and align the teeth; maximum anchorage would be needed. In the maxillary 95
96 Chay and Rabie
American Journal of Orthodontics and Dentofacial Orthopedics July 2002
Fig 1. Pretreatment photos of 34-year-old Indian woman with maxillary left canine replacing missing lateral incisor. Profile photo shows straight lateral facial profile.
Fig 2. Intraoral photos show high gingival margin of maxillary left canine with composite buildup to mimic lateral incisor and bony depression on mesial of tooth.
Fig 3. Pretreatment study models.
Chay and Rabie 97
American Journal of Orthodontics and Dentofacial Orthopedics Volume 122, Number 1
Fig 4. Pretreatment panoramic radiograph shows bony defects at areas of missing maxillary right canine and maxillary left lateral incisor.
Fig 5. Lateral cephalogram reveals skeletal Class I relationship with slight retroclination of incisors.
arch, a fixed appliance would be used to level and align the teeth. Special consideration for the maxillary left canine would be needed: (1) a fixed appliance would be used to torque the root palatally followed by extrusion and alignment, (2) the root would be moved mesially to reduce the bony depression, and (3) the maxillary left canine would substitute for the lateral incisor. Option 2
Under option 3, the mandibular first premolars would be extracted. In the maxillary arch, the left first premolar would be extracted, and the left canine would be moved distally into a Class I relationship, with an open space for the left lateral incisor replacement. This plan had several disadvantages: 1. Option 2 required the extraction of another tooth in the maxillary arch, and the patient would need a
Fig 6. Pretreatment cephalometric tracing.
prosthetic replacement. The prosthetic replacement could require ridge augmentation because of the narrow ridge at the lateral incisor site. This would cause the loss of tooth structure and be an additional expense for the patient. 2. The maxillary right canine was extracted before treatment, and the first right premolar could be used as a canine. This could produce a tooth size discrepancy because the sizes of a premolar and a canine are different; this could cause a midline shift. Option 1 offered symmetry and avoided space closure mechanics. 3. Space closure mechanics in option 2 would require more force on the root of the canine; that could be detrimental to the health of the gingival margins. The gingiva at the canine site showed signs of recession before treatment. Heavier forces are required to produce a counterbalancing moment to control the axial inclination of the canine because the root apex was positioned mesially. Extrusion, on the other hand, requires less force, and the distance of tooth movement is considerably shorter. 4. Option 2 failed to address the bony depression mesial to the canine. This bony depression could become worse as a result of moving the canine distally. Option 1 addressed this point by moving the root of the canine mesially. Because of these disadvantages, option 1 was selected. TREATMENT PROGRESS
The patient’s oral hygiene was monitored regularly throughout treatment. She was referred for extraction of the mandibular right and left first premolars as planned. Initially, only the mandibular arch was banded and bonded, bypassing the anterior teeth to avoid their
98 Chay and Rabie
American Journal of Orthodontics and Dentofacial Orthopedics July 2002
Fig 7. A, Distally positioned bracket on maxillary left canine and auxiliary 0.016-in NiTi wire to level and align it. B, Palatal root torque to maxillary left canine using auxiliary 0.017 ⫻ 0.025–in TMA archwire. C, Extrusion of maxillary left canine with 0.016-in stainless steel archwire with 2 boot loops (butterfly loop); composite buildup gradually removed from incisal tip. D, Maxillary left canine extruded. Note closed boot loops, now passive. E, Bracket on maxillary left canine repositioned. F, Composite buildup on mesioincisal angle of maxillary left canine to mimic lateral incisor.
proclination. A 0.022–in preadjusted slot system and triple tube bands in the maxillary arch and double tube bands in the mandibular arch were used. After initial leveling and aligning with a 0.016 –in NiTi wire, a segmental 0.017 ⫻ 0.025–in titanium molybdenum alloy (TMA) wire with closing loops was used to retract the canines into the extraction spaces. Spontaneous alignment of the mandibular anterior teeth could be seen as space was created during distal movement of the canines. After 3 months, the mandibular incisors and the maxillary dentition were bonded. The bracket on the maxillary left canine was tilted distally to help upright the root. Leveling and aligning were carried out with an auxiliary 0.016 –in NiTi wire placed from the auxiliary tube on the band of the maxillary right molar to the bracket on the maxillary left canine to the auxiliary tube on maxillary left molar (Fig 7, A). The auxiliary wire was then switched to a 0.017 ⫻ 0.025–in TMA wire with palatal root torque to move the roots palatally to increase the thickness of the labial plate of bone before the extrusion (Fig 7, B). Extrusion of the maxillary left canine was carried out with 0.016 –in stainless steel archwire with 2 boot loops (butterfly loop) (Fig 7, C). This loop design is versatile and flexible. Height adjustment of the tooth was easily performed, and activation was simple with no fear of running out of space. As extrusion pro-
ceeded, the composite restoration was gradually removed from the incisal tip of the canine. After sufficient extrusion (Fig 7, D), the bracket was repositioned properly (Fig 7, E), and further alignment was carried out. Meanwhile, the mandibular extraction spaces were closed with closing loops by using a 0.017 ⫻ 0.025–in TMA wire with lingual root torque on the incisors. Both the maxillary and mandibular archwires were changed progressively, with 0.019 ⫻ 0.025–in TMA wire for optimal torque control. Finishing and detailing were completed with 0.017 ⫻ 0.025–in TMA wires. Buccal root torque was increased on teeth numbers 14 and 24 to mimic the prominence of canines. An artistic bend was added to the wire at tooth number 41 to close the open gingival embrasure on the distal. A composite restoration was placed on the mesioincisal angle of the maxillary left canine to mimic a lateral incisor (Fig 7, F). After 28 months of active treatment, the patient was debonded, and a mandibular fixed retainer and a maxillary modified Hawley retainer were inserted (Figs 8-14). RESULTS
All treatment objectives were achieved, and the patient’s esthetic demands were accomplished. The height of the gingival margin of the maxillary left canine was corrected and is nearly at the same level as the contralateral incisor. The clinical crown length of the
American Journal of Orthodontics and Dentofacial Orthopedics Volume 122, Number 1
Fig 8. Posttreatment photos, after 28 months of orthodontic treatment.
Fig 9. Posttreatment intraoral photographs.
Fig 10. Posttreatment study models.
Chay and Rabie 99
100 Chay and Rabie
Fig 11. Posttreatment panoramic radiograph. Note reduction of bony defects on sites of missing maxillary right canine and maxillary left lateral incisor.
American Journal of Orthodontics and Dentofacial Orthopedics July 2002
Fig 13. Postreatment cephalometric tracing.
Fig 14. Superimposed tracings. Fig 12. Posttreatment lateral cephalogram showing normal proclination of incisors.
maxillary left canine was greatly reduced with extrusion and esthetic dentistry to mimic a lateral incisor (Fig 15). The bony depression on the mesial of the maxillary left canine was reduced substantially as the root was moved mesially. The overbite and overjet were improved, and the crossbite and the midlines were corrected. The Class I molar relationship was maintained. Cephalometric analysis of posttreatment radiographs showed proclination of the maxillary incisors (Figs 12 and 13). The lower face height increased slightly, and the mandibular plane angle decreased slightly. Superimposition of pretreatment and posttreatment radiographs showed good control during space closure, and the vertical relationship between the maxillary and mandibular molars was unchanged (Fig 14). The maxillary incisors were torqued palatally, and the mandibular incisors were retracted.
DISCUSSION AND CONCLUSIONS
The role of the orthodontist in improving gingival levels is often overlooked. Innovative orthodontic concepts should be used to enhance biologic structure as well as the esthetics of the supporting tissues. In this patient, the labial gingival margin of the maxillary left canine was moved almost 9 mm incisally through orthodontic extrusion. Extreme care was given to the gingival tissues through prudent planning of the orthodontic treatment. A periodontal evaluation in an adult orthodontic patient must include an assessment of the level and the condition of the attached gingiva—the part of the gingiva that is tightly bound to the underlying bone.7 Earlier animal experiments suggested that the thickness of the gingiva, rather than its surface qualities, could be the key factor that influences the occurrence of recession.8 Proclination of incisors in some patients may be followed by thinning of the alveolar bone, leading to thinning of the attached gingiva. These patients are at higher risk for gingival
Chay and Rabie 101
American Journal of Orthodontics and Dentofacial Orthopedics Volume 122, Number 1
Fig 15. Note gingival level and composite buildup of maxillary left canine to mimic lateral incisor.
recession and loss of attachment.9 Therefore, the gingival condition must receive major attention when planning the orthodontic treatment. In the present case, the attached gingiva was very thin because of the canine prominence, and the gingival margin was 9 mm higher than that of the adjacent teeth (Fig 2). The width of the attached gingiva was 2 mm, considerably less than that of the adjacent teeth. The width of the attached gingiva is measured as the amount of keratinized gingiva between the depth of periodontal probing and the beginning of the alveolar mucosa.7 Therefore, in planning the treatment for this patient, protective measures were taken to increase the thickness of the labial plate of bone and subsequently the thickness of the attached gingiva before extruding the canine. Determining the sequence of this patient’s orthodontic treatment was based on understanding the relationship between orthodontic tooth movement and the different biologic processes that would take place. The first step in the orthodontic treatment was palatal root torque of the maxillary left canine. As the root moved palatally, the periodontal ligament was stretched on the labial surface, leading to bone deposition at the crest of the alveolus.7 The increase in the thickness of the labial plate of bone produced an increase in the thickness of the attached gingiva. It is believed that, for some adult patients, gingival grafting before orthodontic treatment prevents gingival recession.11,12 Increasing the thickness rather than the width of the attached gingiva probably produces this protective effect. Increasing the thickness of the labial plate of bone through palatal root torque could also increase the thickness of the attached gingiva and therefore could also prevent gingival recession. Increasing the thickness of the labial plate of bone may render a healthier
attachment around the tooth and ensure that both the bone and the gingiva follow the tooth during extrusion. The application of palatal torque was made possible on the second visit, before leveling and alignment were completed. The rectangular wire was placed in the auxiliary tubes of the first molars, bypassing all teeth until it was tied to the bracket of the maxillary left canine (Fig 7, B). Four months later, the attached gingiva looked healthier (Fig 7, C), and the prominence of the root was less apparent. The width of the attached gingiva increased as the palatal root torque was improved. This was the indication to begin gradual extrusion of the maxillary canine. As the canine was extruded, the gingiva followed (Fig 7, D). The composite restoration on the incisal edge was removed gradually to provide enough space for the extrusion. After the extrusion was completed, a lateral incisor bracket was placed on the maxillary left canine in an ideal position, and the root was moved mesially to reduce the bony depression. Because the root of the maxillary left canine was moved palatally, it was safe to move the root mesially. This movement was accomplished with a gable bend in the wire, and the mesial of the tooth was extruded and the distal intruded (Fig 7, E). The patient was then referred to a dentist to restore the maxillary left canine with composite to simulate the appearance of a lateral incisor (Fig 7, F). Again, the sequence of treatment ensured a successful result, because the root of the canine was tipped mesially only after the root was moved palatally. Therefore, if the attached gingiva appears thin and vulnerable and there is a chance of gingival recession with orthodontic tooth movement, increasing the thickness of bone through orthodontic intervention may be a way to create healthier attached gingiva before tooth movement.
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