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3D Computed-assisted surgery in orthodontic treatment of impacted canines in palatal position
International Congress Series 1268 (2004) 1203 – 1208
www.ics-elsevier.com
3D Computed-assisted surgery in orthodontic treatment of impacted canines in palatal position D. Bossard a,*, N. Dubos b, F. Trunde c, A. Huet b, J.L Coudert b b
a Imagerie me´dicale, Saint Jean-Lyon, Lyon, France Service de Consultation et de Traitement Dentaire, Hospices Civils de Lyon, Lyon, France c Laboratoire LISA, CPE Lyon, Lyon, France
Abstract. An original method of mini-invasive oral surgery based on 3D images from computed tomography is presented. Fourteen patients referred for treatment of unerupted canine in palatal location underwent a multislice CT scan (MSCT). The patient data were analyzed with an original 3D imaging software based on «region growing» method. The 3D images were then segmented in order to separate bone teeth and mucosae. The optimal position of the expected bracket attachment was calculated and reported on the 3D images of the canine to be treated. A virtual geometric construction of this optimal point was determined using neighboring teeth and then transposed to the patient’s teeth, allowing then a limited surgical incision when sticking the bracket on the impacted canine. For all treated patients, the orthodontic treatment was facilitated by this procedure which allowed a more accurate and more limited surgical incision. D 2004 CARS and Elsevier B.V. All rights reserved. Keywords: Computed tomography; 3D Imaging; Orthodontics
1. Introduction An impacted canine is a very frequent condition, requiring a surgical and orthodontic approach, to prevent growth abnormalities of adjacent teeth, and moving the impacted tooth into the right location. Thus, the exact location of the impacted canine which is not seen under the palatal mucosae is difficult, making the surgical incision hazardous.
Abbreviations: CT, computed tomography; MSCT, multislice computed tomography; 3D, three dimensional. * Corresponding author. Imagerie Medicale, Clinique Saint-Jean, 30 rue Bataille, 69450 Lyon, France. Tel.: +33-478766860; fax: +33-5-78009685. E-mail address: [email protected] (D. Bossard). 0531-5131/ D 2004 CARS and Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2004.03.280
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D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
Fig. 1. 3D images showing the different structures: bone, mucosae and teeth.
We present a new strategy using surgical planning based on 3D imaging from MSCT data. 2. Materials and method Fourteen patients (11 females, 3 males, mean age: 12,83 years) where referred to the Dental Diagnosis and Treatment Center (SCTD Lyon France) with the diagnosis of unerupted canine in palatal location, after clinical examination and plain film radiographs. All patients underwent a MSCT exam (16 detectors—Siemens somatom 16, Erlangen, Germany) in the same Imaging Center (Clinique Saint-Jean, Lyon, France). Parameters of the MSCT scans were as follows: slice thickness = 0.75 mm, pitch = 6 mm/s, acquisition time = 7.6 s, 80 mA s and 120 kV per slice, total dose delivered =18.14 mGy.
Fig. 2. The mucosae are virtually removed; the included canine appears.
D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
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Fig. 3. Three marks are placed on the impacted canine, according to the position of the bracket attachment.
Images were reconstructed with a thickness of 0.5 mm, every 0.5 mm, and stored as native slices according to the Digital Imaging for Communication in Medicine (DICOM) protocol. All patients data were analyzed with an original 3D imaging software (Lisa Development Studio, Hospices Civils de Lyon, France). This software is based on region growing method. The 3D images were segmented in order to separate bone, teeth and palatal mucosae (Figs. 1 and 2). These structures were then directly movable on the computer screen.
Fig. 4. These three marks are figured on the mucosae, and adjacent teeth are chosen (white points) to calculate the position of the marks in mouth.
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D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
Fig. 5. According to the adjacent teeth, the marks are drawn on the mucosae.
They could be represented isolated or combined with different degrees of transparency or depth. The optimal position of the bracket attachment was then calculated on the palatal face of the teeth and projected on the palatal mucosae in the 3D image (Fig. 3). A virtual geometric construction of this optimal point was determined using neighbouring teeth position (Fig. 4) and then transposed to the patient’s palatal mucosae (Fig. 5), allowing then a limited surgical incision when sticking the bracket on the impacted canine (Fig. 6). 3. Results The 14 young patients underwent MSCT exams, virtual planning of surgery with the 3D software, and then oral surgery under local anesthesia. For each of the 21 impacted canines in palatal position, surgical treatment was facilitated by this procedure which allowed a more accurate and more limited surgical incision. The mean surgical time reached 7 min. No adverse events occurred.
Fig. 6. Surgical incision is made, and the impacted canine is stuck on the bracket.
D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
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4. Discussion An impacted tooth is a condition in which a tooth is embedded in the alveolus so that its eruption is prevented or the tooth is locked in position by bone or by the adjacent teeth. With the exception of the maxillary and mandibular third molars, the maxillary permanent canine is the most commonly impacted tooth, with a reported incidence of approximately 1 – 2% of the population [1]. The majority of impactions are found in women. Bilateral impactions are less commonly encountered than single impactions. Eighty-five percent of impacted canines are in palatal position, 15% in labial position [2]. Treating impacted palatal canines usually involves surgery and orthodontic therapy aiming at correcting the tooth position. Orthodontic management [3] of these impacted maxillary canines can be very complex and requires a carefully planned interdisciplinary approach [4– 6]. These teeth are surgically exposed and moved toward the arch wire after the maxillary arch is stabilized by progressing to a rigid arch wire. This movement is accomplished by bonding some form of orthodontic attachment to the exposed tooth and application of traction to move the impacted tooth in a desired direction [7 –9]. In orthodontic treatment planning, the exact localization of the position of impacted canines is of importance. It is well known that using panoramic radiographs does not provide satisfactory information about the location of impacted teeth [10,12]. More recently, CT appeared to be a very reliable method to identify the position of the impacted teeth (either labial, or palatal) of the upper maxillary, or relationships between included teeth and mandibular nerve [11,13,14]. While computer-aided procedures were described in implantology and mandibular distraction, several authors, pointing the difficulty to guess the exact location of this impacted teeth in mouth, developed new methods based on measurement from plain films or CT images [15 – 17]. These methods, however, were not satisfactory since they did not provide a spatial representation of the area of interest, nor accurate marks for the intervention in mouth. Our method combines surgical planning on virtual images from CT examinations, and translation of these data into the mouth. It is a true 3D CT-assisted mini-invasive surgery. This preliminary study including 14 patients (representing 21 treated teeth) showed encouraging results in terms of safety and surgical efficiency. Further studies are required in order to confirm these first results. 5. Conclusion The method we present is based on a precise calculation of the location of the tooth, using 3D imaging tools, allowing an accurate planning of oral surgery, from computed tomography data. It is a simple and safe method of work, permitting a very limited and time-saving surgical procedure. Acknowledgements This work was supported by the PHRC 2001 regional program (Disant F.F., Jourlin M., Coudert J.L.).
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D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
References [1] C. Favre De Thierrens, et al., Inclusion dentaire (I). Aspects biologiques, odontoge´niques, physiologiques et pathologiques. Encycl Me´d Chir, Stomatologie (Elsevier, Paris) 22-032-A-15 (2003) 1 – 10. [2] K. Jarjoura, P. Crespo, J.B. Fine, Maxillary canine impactions: orthodontic and surgical management. Compend. Contin. Educ. Dent. 23 (2002) 23-6, 28 30-1. [3] V. Kokich, D.P. Mathews, Surgical and orthodontic management of impacted teeth, Dent. Clin. North Am. 37 (1993) 181 – 204. [4] Y. Shapira, M.M. Kuftinec, Early diagnosis and interception of potential maxillary canine impaction, J. Am. Dent. Assoc. 129 (1998) 1450 – 1454. [5] J.A. Stewart, et al., Factors that relate to treatment duration for patients with palatally impacted maxillary canines, Am. J. Orthod. Dentofac. Orthop. 119 (2001) 216 – 225. [6] M.M. Kufitnec, Y. Shapira, The impacted maxillary canine: I. Review of concepts, ASD Am. J. Orthod. Dentofac. Orthop. 119 (2) (2001 Feb) 127 – 134. [7] S.E. Bishara, Impacted maxillary canines: a review, Am. J. Orthod. Dentofac. Orthop. 101 (1992) 159 – 171. [8] M.F. Caminiti, et al., Outcomes of the surgical exposure, bonding and eruption of 82 impacted maxillary canines, J. Can. Dent. Assoc. 64 (1998) 572 – 579. [9] Y. Shapira, M.M. Kuftinec, Maxillary tooth transpositions: characteristic features and accompanying dental anomalies, C.J. Dent. Child. 62 (5) (1995 Sep. – Oct.) 317 – 324. [10] L. Bodner, et al., Localizing maxillary canines using dental panoramic tomography, Br. Dent. J. 179 (1995) 416 – 420. [11] A. Becker, Image accuracy of plain film radiography and computerized tomography in assessing morphological abnormality of impacted teeth, Am. J. Orthod. Dentofac. Orthop. 120 (2001) 623 – 628. [12] S. Chaushu, G. Chaushu, A. Becker, The use of panoramic radiographs to localize displaced maxillary canines, Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endo. 88 (1999) 511 – 516. [13] D. Pajoni, E. Jouan, P. Harmann, Interet des reconstructions tridimentionnelles dans la localisation des canines incluses, Rev. Orthop. Dento-Fac. 29 (1995) 473 – 480. [14] R. Schmelzeisen, et al., Computer-aides procedures in implantology, distraction and cranio-maxiofacial surgery, Ann. R. Aust. Coll. Dent. Surg. 16 (2002 Oct) 46 – 49. [15] K. Hayaschi, J. Uechi, I. Mizoguchi, Three-dimensional analysis of dental casts based on a new defined palatal reference plane, Angle Orthod. 73 (5) (2003 Oct) 539 – 544. [16] S.G. Jacobs, Radiographic localization of unerupted teeth: further findings about the vertical tube shift method and other localization techniques, Am. J. Orthod. Dentofac. Orthop. 118 (2000) 439 – 447. [17] E.L.K. Tang, Multispecialty team management of a case with impacted maxillary permanent canines, J. Dent. Child. 59 (1992) 190 – 195.
www.ics-elsevier.com
3D Computed-assisted surgery in orthodontic treatment of impacted canines in palatal position D. Bossard a,*, N. Dubos b, F. Trunde c, A. Huet b, J.L Coudert b b
a Imagerie me´dicale, Saint Jean-Lyon, Lyon, France Service de Consultation et de Traitement Dentaire, Hospices Civils de Lyon, Lyon, France c Laboratoire LISA, CPE Lyon, Lyon, France
Abstract. An original method of mini-invasive oral surgery based on 3D images from computed tomography is presented. Fourteen patients referred for treatment of unerupted canine in palatal location underwent a multislice CT scan (MSCT). The patient data were analyzed with an original 3D imaging software based on «region growing» method. The 3D images were then segmented in order to separate bone teeth and mucosae. The optimal position of the expected bracket attachment was calculated and reported on the 3D images of the canine to be treated. A virtual geometric construction of this optimal point was determined using neighboring teeth and then transposed to the patient’s teeth, allowing then a limited surgical incision when sticking the bracket on the impacted canine. For all treated patients, the orthodontic treatment was facilitated by this procedure which allowed a more accurate and more limited surgical incision. D 2004 CARS and Elsevier B.V. All rights reserved. Keywords: Computed tomography; 3D Imaging; Orthodontics
1. Introduction An impacted canine is a very frequent condition, requiring a surgical and orthodontic approach, to prevent growth abnormalities of adjacent teeth, and moving the impacted tooth into the right location. Thus, the exact location of the impacted canine which is not seen under the palatal mucosae is difficult, making the surgical incision hazardous.
Abbreviations: CT, computed tomography; MSCT, multislice computed tomography; 3D, three dimensional. * Corresponding author. Imagerie Medicale, Clinique Saint-Jean, 30 rue Bataille, 69450 Lyon, France. Tel.: +33-478766860; fax: +33-5-78009685. E-mail address: [email protected] (D. Bossard). 0531-5131/ D 2004 CARS and Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2004.03.280
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D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
Fig. 1. 3D images showing the different structures: bone, mucosae and teeth.
We present a new strategy using surgical planning based on 3D imaging from MSCT data. 2. Materials and method Fourteen patients (11 females, 3 males, mean age: 12,83 years) where referred to the Dental Diagnosis and Treatment Center (SCTD Lyon France) with the diagnosis of unerupted canine in palatal location, after clinical examination and plain film radiographs. All patients underwent a MSCT exam (16 detectors—Siemens somatom 16, Erlangen, Germany) in the same Imaging Center (Clinique Saint-Jean, Lyon, France). Parameters of the MSCT scans were as follows: slice thickness = 0.75 mm, pitch = 6 mm/s, acquisition time = 7.6 s, 80 mA s and 120 kV per slice, total dose delivered =18.14 mGy.
Fig. 2. The mucosae are virtually removed; the included canine appears.
D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
1205
Fig. 3. Three marks are placed on the impacted canine, according to the position of the bracket attachment.
Images were reconstructed with a thickness of 0.5 mm, every 0.5 mm, and stored as native slices according to the Digital Imaging for Communication in Medicine (DICOM) protocol. All patients data were analyzed with an original 3D imaging software (Lisa Development Studio, Hospices Civils de Lyon, France). This software is based on region growing method. The 3D images were segmented in order to separate bone, teeth and palatal mucosae (Figs. 1 and 2). These structures were then directly movable on the computer screen.
Fig. 4. These three marks are figured on the mucosae, and adjacent teeth are chosen (white points) to calculate the position of the marks in mouth.
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D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
Fig. 5. According to the adjacent teeth, the marks are drawn on the mucosae.
They could be represented isolated or combined with different degrees of transparency or depth. The optimal position of the bracket attachment was then calculated on the palatal face of the teeth and projected on the palatal mucosae in the 3D image (Fig. 3). A virtual geometric construction of this optimal point was determined using neighbouring teeth position (Fig. 4) and then transposed to the patient’s palatal mucosae (Fig. 5), allowing then a limited surgical incision when sticking the bracket on the impacted canine (Fig. 6). 3. Results The 14 young patients underwent MSCT exams, virtual planning of surgery with the 3D software, and then oral surgery under local anesthesia. For each of the 21 impacted canines in palatal position, surgical treatment was facilitated by this procedure which allowed a more accurate and more limited surgical incision. The mean surgical time reached 7 min. No adverse events occurred.
Fig. 6. Surgical incision is made, and the impacted canine is stuck on the bracket.
D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
1207
4. Discussion An impacted tooth is a condition in which a tooth is embedded in the alveolus so that its eruption is prevented or the tooth is locked in position by bone or by the adjacent teeth. With the exception of the maxillary and mandibular third molars, the maxillary permanent canine is the most commonly impacted tooth, with a reported incidence of approximately 1 – 2% of the population [1]. The majority of impactions are found in women. Bilateral impactions are less commonly encountered than single impactions. Eighty-five percent of impacted canines are in palatal position, 15% in labial position [2]. Treating impacted palatal canines usually involves surgery and orthodontic therapy aiming at correcting the tooth position. Orthodontic management [3] of these impacted maxillary canines can be very complex and requires a carefully planned interdisciplinary approach [4– 6]. These teeth are surgically exposed and moved toward the arch wire after the maxillary arch is stabilized by progressing to a rigid arch wire. This movement is accomplished by bonding some form of orthodontic attachment to the exposed tooth and application of traction to move the impacted tooth in a desired direction [7 –9]. In orthodontic treatment planning, the exact localization of the position of impacted canines is of importance. It is well known that using panoramic radiographs does not provide satisfactory information about the location of impacted teeth [10,12]. More recently, CT appeared to be a very reliable method to identify the position of the impacted teeth (either labial, or palatal) of the upper maxillary, or relationships between included teeth and mandibular nerve [11,13,14]. While computer-aided procedures were described in implantology and mandibular distraction, several authors, pointing the difficulty to guess the exact location of this impacted teeth in mouth, developed new methods based on measurement from plain films or CT images [15 – 17]. These methods, however, were not satisfactory since they did not provide a spatial representation of the area of interest, nor accurate marks for the intervention in mouth. Our method combines surgical planning on virtual images from CT examinations, and translation of these data into the mouth. It is a true 3D CT-assisted mini-invasive surgery. This preliminary study including 14 patients (representing 21 treated teeth) showed encouraging results in terms of safety and surgical efficiency. Further studies are required in order to confirm these first results. 5. Conclusion The method we present is based on a precise calculation of the location of the tooth, using 3D imaging tools, allowing an accurate planning of oral surgery, from computed tomography data. It is a simple and safe method of work, permitting a very limited and time-saving surgical procedure. Acknowledgements This work was supported by the PHRC 2001 regional program (Disant F.F., Jourlin M., Coudert J.L.).
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D. Bossard et al. / International Congress Series 1268 (2004) 1203–1208
References [1] C. Favre De Thierrens, et al., Inclusion dentaire (I). Aspects biologiques, odontoge´niques, physiologiques et pathologiques. Encycl Me´d Chir, Stomatologie (Elsevier, Paris) 22-032-A-15 (2003) 1 – 10. [2] K. Jarjoura, P. Crespo, J.B. Fine, Maxillary canine impactions: orthodontic and surgical management. Compend. Contin. Educ. Dent. 23 (2002) 23-6, 28 30-1. [3] V. Kokich, D.P. Mathews, Surgical and orthodontic management of impacted teeth, Dent. Clin. North Am. 37 (1993) 181 – 204. [4] Y. Shapira, M.M. Kuftinec, Early diagnosis and interception of potential maxillary canine impaction, J. Am. Dent. Assoc. 129 (1998) 1450 – 1454. [5] J.A. Stewart, et al., Factors that relate to treatment duration for patients with palatally impacted maxillary canines, Am. J. Orthod. Dentofac. Orthop. 119 (2001) 216 – 225. [6] M.M. Kufitnec, Y. Shapira, The impacted maxillary canine: I. Review of concepts, ASD Am. J. Orthod. Dentofac. Orthop. 119 (2) (2001 Feb) 127 – 134. [7] S.E. Bishara, Impacted maxillary canines: a review, Am. J. Orthod. Dentofac. Orthop. 101 (1992) 159 – 171. [8] M.F. Caminiti, et al., Outcomes of the surgical exposure, bonding and eruption of 82 impacted maxillary canines, J. Can. Dent. Assoc. 64 (1998) 572 – 579. [9] Y. Shapira, M.M. Kuftinec, Maxillary tooth transpositions: characteristic features and accompanying dental anomalies, C.J. Dent. Child. 62 (5) (1995 Sep. – Oct.) 317 – 324. [10] L. Bodner, et al., Localizing maxillary canines using dental panoramic tomography, Br. Dent. J. 179 (1995) 416 – 420. [11] A. Becker, Image accuracy of plain film radiography and computerized tomography in assessing morphological abnormality of impacted teeth, Am. J. Orthod. Dentofac. Orthop. 120 (2001) 623 – 628. [12] S. Chaushu, G. Chaushu, A. Becker, The use of panoramic radiographs to localize displaced maxillary canines, Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endo. 88 (1999) 511 – 516. [13] D. Pajoni, E. Jouan, P. Harmann, Interet des reconstructions tridimentionnelles dans la localisation des canines incluses, Rev. Orthop. Dento-Fac. 29 (1995) 473 – 480. [14] R. Schmelzeisen, et al., Computer-aides procedures in implantology, distraction and cranio-maxiofacial surgery, Ann. R. Aust. Coll. Dent. Surg. 16 (2002 Oct) 46 – 49. [15] K. Hayaschi, J. Uechi, I. Mizoguchi, Three-dimensional analysis of dental casts based on a new defined palatal reference plane, Angle Orthod. 73 (5) (2003 Oct) 539 – 544. [16] S.G. Jacobs, Radiographic localization of unerupted teeth: further findings about the vertical tube shift method and other localization techniques, Am. J. Orthod. Dentofac. Orthop. 118 (2000) 439 – 447. [17] E.L.K. Tang, Multispecialty team management of a case with impacted maxillary permanent canines, J. Dent. Child. 59 (1992) 190 – 195.