- Email: [email protected]
Hemisection of fused teeth involving a maxillary permanent incisor and a supernumerary tooth
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
Available online at www.sciencedirect.com
Pediatric Dental Journal journal homepage: www.elsevier.com/locate/pdj
Case Report
Hemisection of fused teeth involving a maxillary permanent incisor and a supernumerary tooth Jiajia Zheng a, Yukari Shinonaga b, Saki Kawai b, Yoko Abe b, Kyoko Harada b, Kenji Arita b,* a b
The First Outpatient Dental Clinic, Peking University School and Hospital of Stomatology, Beijing, China Department of Pediatric Dentistry, Osaka Dental University, Osaka, Japan
article info
abstract
Article history:
Purpose: Fusion is the union of adjacent teeth with or without pulp involvement. It can lead
Received 21 July 2015
to serious esthetic problems and malocclusion. Here we report two rare cases of fusion of a
Received in revised form
permanent maxillary incisor with a supernumerary tooth that we successfully corrected
7 September 2015
using hemisection, which was performed after we confirmed that the roots had developed
Accepted 7 September 2015
and separated.
Available online 25 November 2015
Case reports: In the first case, the whole vital pulp was preserved. In the second case, partial pulpotomy was performed.
Keywords:
Conclusion: The differential diagnosis and appropriate management of permanent anterior
Fused tooth
fused teeth are essential to attain a favorable outcome and minimize the risk of any
Hemisection
complications.
Partial pulpotomy
Copyright © 2015 The Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All
Restoration
rights reserved.
Supernumerary tooth
1.
Introduction
Fusion is defined as an embryonic union of normally separated tooth germs and represents a connection at the level of dentin between two independently developing primary or permanent teeth [1]. Fusion may be partial or total, depending on the stage of tooth development at the time of union [2,3]. Fusion is less prevalent in the permanent dentition than in the primary dentition [3]. The incidence of this anomaly is >0.1% in the permanent dentition [4]. Furthermore, fused teeth are
mainly found in the anterior region. Fusion can lead to serious esthetic problems and malocclusion, especially when supernumerary elements are involved [3,5]. Various treatment methods have been reported to solve these problems, such as sectioning and extraction of the supernumerary tooth, and restoration or prosthetic treatment of the crown with or without endodontic treatment [6e10]. In the two cases reported here, we describe the hemisection of maxillary central incisors fused with supernumerary teeth. The patients' guardians provided informed consent for this report.
* Corresponding author. Department of Pediatric Dentistry, Osaka Dental University, 1-5-17, Otemae, Chuo-ku, Osaka 540-0008, Japan. E-mail address: [email protected] (K. Arita). http://dx.doi.org/10.1016/j.pdj.2015.09.001 0917-2394/Copyright © 2015 The Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All rights reserved.
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
2.
Case reports
2.1.
Case 1
A 7-year-old girl was referred to the Department of Pediatric Dentistry at Osaka Dental University Hospital, Osaka, Japan, with a chief complaint of an esthetic problem in the maxillary permanent incisor region. Her medical history was not relevant and there was no family history of dental anomalies. Intraoral examination showed a labial erupted permanent maxillary left central incisor. Also, an erupted supernumerary tooth resembling a miniature incisor was present between the left and right central incisors, and fused to the left central incisor (Fig. 1A and B). The fused tooth had a
85
broad crown and a small groove was observed between the crown of the left incisor and the supernumerary tooth on the labial and palatal sides. The patient had mixed dentition and crowding in the anterior region due to lack of space. Radiographic examination revealed that the maxillary left central incisor had two root canals and two underdeveloped roots (Fig. 1C and D). There was no missing primary or permanent tooth. Computer tomography (CT) images showed that the root canals were not completely separated (Fig. 1E and F). The initial treatment plan was as follows: (1) periodic follow up and checking for pulp separation and development; (2) if there was no connection between the root pulps of the supernumerary tooth and left central incisor, hemisection and extraction of the fused supernumerary tooth; (3)
Fig. 1 e Case 1, first visit. An abnormally wide maxillary left central incisor as a result of fusion between the left central incisor and supernumerary tooth: (A) frontal; and (B) palatal views. The maxillary left central incisor had two root canals and two underdeveloped roots: (C) panoramic radiograph; (D) periapical radiograph. Computed tomography images: (E) horizontal cross-section of root apex; and (F) three-dimensional image of fused teeth.
86
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
reshaping of the left upper central incisor crown through restorative techniques; and (4) alignment and space closure by orthodontic treatment. After 19 months' follow up and monitoring, another regular examination and CT were performed (Fig. 2). The radiograph showed that the roots were separate and nearly fully formed, however, the fused tooth still had a wide-open apex (Fig. 2B). The root canals seemed to be separate as seen in some of the CT images (Fig. 2C and D). Surgical hemisection was scheduled, and the treatment objectives, procedures, the risk of pulp exposure, and alternatives were explained to the patient and her parents. Surgical treatment was performed under local anesthesia 21 months from her first visit to our department. The crown was sectioned using a diamond bur along the mesial side of the groove (Fig. 3A and B). The buccal and palatal flaps were raised, and the conjoint supernumerary tooth including the root was completely removed (Fig. 3C and D). The two teeth were united by enamel, dentin, and cementum, however, the pulp chambers were not involved. Based on these findings, the diagnosis of fusion was confirmed. The mesial portion of the prepared central incisor was reconstructed using the sandwich technique [11]. Glass ionomer cement was used as a base, and composite resin was used for esthetic restoration. Afterward, the flap was repositioned and sutured (Fig. 3E). One week after the operation, wound healing was good and the sutures were removed. The shape of
the tooth crown was also modified using composite resin (Fig. 4A). In order to correct the position of the central incisor, minimal tooth movement was planned. The orthodontic appliance was planned using metal brackets. Following the placement of maxillary brackets, a NieTi arch wire was connected to the bracket slots to correct the upper left central incisor (Fig. 4B). After a 6-month follow-up period, the minimal tooth movement resulted in good esthetics (Fig. 4C and D). The root of the left central incisor formed smoothly. The prognosis of alveolar bone was also satisfactory (Fig. 4EeG).
2.2.
Case 2
A 7-year-old girl was referred to the Department of Pediatric Dentistry at Tokushima University Hospital, Tokushima, Japan, with anterior supernumerary teeth, complaining about malocclusion. The medical and dental histories were not relevant and there was no family history of dental anomalies. Intraoral and radiographic examinations revealed an erupted maxillary central supernumerary tooth (Fig. 5: dotted arrow). Furthermore, radiographic examination of the upper incisors revealed another impacted supernumerary tooth fused with the maxillary right central incisor (Fig. 5A: solid lined arrow). The erupted supernumerary tooth was extracted during her first visit. After several months, the impacted
Fig. 2 e Case 1 at 19 months follow-up and check-up period. (A) Frontal view; (B) periapical radiograph; (C) computed tomography horizontal cross-section image of root apex; and (D) three-dimensional computed tomography image of fused teeth.
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
87
Fig. 3 e Case 1, surgical procedure. Separation of tooth crowns and roots: (A) frontal view; (B) periapical radiograph taken during the operation. Extraction of the supernumerary tooth: (C) postextraction; (D) extracted root of supernumerary tooth; and (E) suture.
maxillary right incisor with supernumerary tooth was surgically exposed (Fig. 5B and C). When the patient was 8 years old, the two roots of the supernumerary tooth and the maxillary right central incisor were almost fully formed and the root dentine and canals were separate as observed in the periapical radiograph (Fig. 5D). Surgical hemisection was performed (Fig. 5E). The hemisection procedure was almost the same as that described for Case 1. In this case, a pulp exposure of size 1 mm 8 mm was noted at the maxillary right central incisor, when the fused teeth crowns were separated (Fig. 5F). Therefore, a partial pulpotomy using calcium hydroxide (Ca(OH)2) as a pulp-capping agent was carried out. Three weeks later, dentin bridge formation was detected at the pulp-capped site, with a temporary seal, Ca(OH)2, and necrotic tissue. The right central incisor was restored using glass ionomer cement and composite resin
(Fig. 6A). A part of the root of the supernumerary tooth remained close to the root of maxillary right central incisor (Fig. 6B). The diastema was closed with minimal tooth movement using the same method of Case 1 (Fig. 6C). Over the past 10 years, no pulp necrosis had become evident in the follow-up observations, and the prognosis of alveolar bone around the root of the maxillary right central incisor and remaining root of the supernumerary tooth was also satisfactory (Fig. 6D and E).
3.
Discussion
Fused teeth may lead to serious esthetic problems, malocclusion, and psychological problems, especially in children and adolescents [12]. Therefore, these problems need
88
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
Fig. 4 e Case 1. (A) One week follow up after the operation; (B) minimal tooth movement; (C, D) after removal of metal brackets. Periapical radiographs: (E) just after the operation; (F) after 5 months; and (G) after 6 months.
immediate attention. Different approaches for the management of fused teeth have been suggested because endodontic, esthetic, orthodontic, periodontal, and functional problems have to be considered. Hemisection is one of the recommended treatments if the fused tooth possesses separate roots [13]. If the pulp chambers are connected, endodontic treatment also becomes necessary. However, the majority of fused teeth are identified when the roots of the teeth are developing. In both present cases, we delayed the hemisection treatment until the roots were fully developed and the pulp chambers were separated. Moreover, whenever pulp exposure occurs in immature teeth with partially developed roots during separation of the fused tooth, it is appropriate to employ a clinical technique which preserves as much vital pulp as possible. This enables continued physiologic dentin deposition and complete root development [14]. In Case 1, based on the presurgical examination results, a conservative treatment option was selected. Extraction of the supernumerary tooth was chosen to solve the esthetic problem and obtain space for alignment. Because no pulp exposure was observed following separation, no endodontic therapy was performed. The sandwich technique [11] using glass ionomer cement and composite resin was used to reconstruct the mesial part of the upper left central incisor. The clinical advantages of this technique include pulp protection, fluoride release, minimum composite
mass, and consequently decreased polymerization shrinkage [15,16]. In Case 2, after separation of the tooth, pulp exposure of the right maxillary central incisor was detected, so that partial pulpotomy using Ca(OH)2 was performed to preserve the vital pulp as much as possible, according to the modified two-step procedure [15]. The advantages of this modified technique compared with the conventional pulpotomy technique are as follows: (1) prevention of inflammatory internal root resorption by removing long-term and chronic pulpal stimulation due to Ca(OH)2; (2) a dead layer between the dentin bridge and lining cement does not form due to removal of the necrotic layer on the dentin bridge; it improves the prognosis of restoration; and (3) the formation of the layer can be observed directly, about 1 month after pulpotomy. Abnormally shaped anterior teeth have an unesthetic appearance due to irregular morphology and crowding problems. The cases reported here both comprised fusion of one maxillary central incisor and a supernumerary tooth. Cetinbas et al. [5] suggested that a reduction of the width of the fused tooth would provide enough space for teeth alignment. However, Kim et al. [12] reported a case in which after hemisection, the abnormally positioned lateral incisor and canine biologically moved to normal positions without orthodontic treatment. In hemisection of fused teeth, the periodontal ligament of the preserved healthy tooth may
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
89
Fig. 5 e Case 2. (A) Periapical radiograph at the first visit. One erupted supernumerary tooth (dotted arrow) and unerupted supernumerary tooth fused to the right maxillary central incisor (solid lined arrow); (B) the fenestration of the impacted maxillary right incisor with the supernumerary tooth; (C) fused tooth started to be erupted; (D) periapical radiograph. It was confirmed that the roots of the supernumerary tooth and maxillary right central incisor were fully formed and the root canals were separated; (E) separation of tooth crowns and roots; and (F) pulp exposure (white arrow).
be lost partly in the same way as replanted teeth after dental trauma or avulsion. A few case reports described postoperative complications, such as hypersensitivity, pulpitis, and external root resorption [17,18]. However, the roots of central incisors in our cases developed favorably and the prognosis of alveolar bone was also satisfactory. Particularly in Case 2, the remaining root of the supernumerary tooth close to the maxillary incisor did not show any periodontal damage over 10 years. It is considered that the roots of
supernumerary teeth and central incisors were fused in the cementum. Based on the present cases, suitable conditions for hemisection of fused teeth are as follows: (1) the root dentine and canals of fused teeth were completely separated; and (2) the cementum of those roots were completely separated or partially combined. Vast knowledge about alternative operative techniques and proper evaluation are required to manage such cases. An
90
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
Fig. 6 e Case 2. (A) Restoration using sandwich technique; (B) periapical radiograph. A part of the supernumerary teeth remained (black arrow); (C) minimal tooth movement. After a 10-year follow-up period: (D) periapical radiograph; (E) panoramic radiograph.
appropriate treatment plan has to be formulated to minimize the risk of any complications.
Conflicts of interest The authors declare that there are no conflicts of interest that could be perceived as prejudicing the impartiality of the research reported.
references
[1] Brad N, Douglas D, Carl A, et al. Oral and maxillofacial pathology. 3rd ed. Philadelphia, PA: Saunders Elsevier; 2009. [2] Dinesh B, Sapna H. A talon cusp on fused teeth associated with hypodontia: report of a unique case. Eur J Dent 2010;4:75e80. [3] Sammartino G, Cerone V, Gasparro R, et al. Multidisciplinary approach to fused maxillary central incisors: a case report.
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
[4] [5]
[6]
[7]
[8]
[9]
[10]
J Med Case Rep 2014;8. http://dx.doi.org/10.1186/1752-19478-398. Kelly R. Gemination, fusion, or both? Oral Surg 1978;45:325e6. Cetinbas T, Halil S, Akcam O, et al. Hemisection of a fused tooth. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2007;104:e120e4. Karac¸ay S, Gurton U, Olmez H, et al. Multidisciplinary treatment of “twinned” permanent teeth: two case reports. J Dent Child 2004;71:80e6. David T, Krakowiak A, Pirani B. Nonendodontic coronal resection of fused and geminated vital teeth: a new technique. Oral Surg Oral Med Oral Pathol 1997;83:501e5. Hu¨lsmann M, Bahr R, Grohmann U. Hemisection and vital treatment of a fused tooth: literature review and case report. Endod Dent Traumatol 1997;13:253e8. Braun A, Appel T, Frentzen M. Endodontic and surgical treatment of a geminated maxillary incisor. Int Endod J 2003;36:380e6. Karacay S, Guven G, Koymen R. Management of a fused central incisor in association with a macrodont lateral incisor: a case report. Pediatr Dent 2006;28:336e40.
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[11] Croll P. The “sandwich” technique. J Esthet Restor Dent 2004;16:210e2. [12] Kim Y, Choi C, Chung J. Management of the fused permanent upper lateral incisor: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;111:649e52. [13] Itkin B, Barr S. Comprehensive management of the double tooth: report of case. J Am Dent Assoc 1975;90:1269e72. [14] Fong D, Davis J. Partial pulpotomy for immature permanent teeth, its present and future. Pediatr Dent 2002;24:20e32. [15] McLean W, Wilson D. The clinical development of the glassionomer cement. III. The erosion lesion. Aust Dent J 1977;22:190e5. [16] Farah S, Orton G, Collard M. Shear bond strength of chemical and light-cured glass ionomer cements bonded to resin composites. Aust Dent J 1998;43:81e6. [17] Blank S, Ogg R, Levy R. A fused central incisoreperiodontal considerations in comprehensive treatment. J Periodontol 1985;56:21e4. [18] Kayalibay H, Uzarnis M, Akalin A. The treatment of a fusion between the maxillary central incisor and supernumerary tooth: report of a case. J Clin Pediatr Dent 1996;20:237e40.
Available online at www.sciencedirect.com
Pediatric Dental Journal journal homepage: www.elsevier.com/locate/pdj
Case Report
Hemisection of fused teeth involving a maxillary permanent incisor and a supernumerary tooth Jiajia Zheng a, Yukari Shinonaga b, Saki Kawai b, Yoko Abe b, Kyoko Harada b, Kenji Arita b,* a b
The First Outpatient Dental Clinic, Peking University School and Hospital of Stomatology, Beijing, China Department of Pediatric Dentistry, Osaka Dental University, Osaka, Japan
article info
abstract
Article history:
Purpose: Fusion is the union of adjacent teeth with or without pulp involvement. It can lead
Received 21 July 2015
to serious esthetic problems and malocclusion. Here we report two rare cases of fusion of a
Received in revised form
permanent maxillary incisor with a supernumerary tooth that we successfully corrected
7 September 2015
using hemisection, which was performed after we confirmed that the roots had developed
Accepted 7 September 2015
and separated.
Available online 25 November 2015
Case reports: In the first case, the whole vital pulp was preserved. In the second case, partial pulpotomy was performed.
Keywords:
Conclusion: The differential diagnosis and appropriate management of permanent anterior
Fused tooth
fused teeth are essential to attain a favorable outcome and minimize the risk of any
Hemisection
complications.
Partial pulpotomy
Copyright © 2015 The Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All
Restoration
rights reserved.
Supernumerary tooth
1.
Introduction
Fusion is defined as an embryonic union of normally separated tooth germs and represents a connection at the level of dentin between two independently developing primary or permanent teeth [1]. Fusion may be partial or total, depending on the stage of tooth development at the time of union [2,3]. Fusion is less prevalent in the permanent dentition than in the primary dentition [3]. The incidence of this anomaly is >0.1% in the permanent dentition [4]. Furthermore, fused teeth are
mainly found in the anterior region. Fusion can lead to serious esthetic problems and malocclusion, especially when supernumerary elements are involved [3,5]. Various treatment methods have been reported to solve these problems, such as sectioning and extraction of the supernumerary tooth, and restoration or prosthetic treatment of the crown with or without endodontic treatment [6e10]. In the two cases reported here, we describe the hemisection of maxillary central incisors fused with supernumerary teeth. The patients' guardians provided informed consent for this report.
* Corresponding author. Department of Pediatric Dentistry, Osaka Dental University, 1-5-17, Otemae, Chuo-ku, Osaka 540-0008, Japan. E-mail address: [email protected] (K. Arita). http://dx.doi.org/10.1016/j.pdj.2015.09.001 0917-2394/Copyright © 2015 The Japanese Society of Pediatric Dentistry. Published by Elsevier Ltd. All rights reserved.
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
2.
Case reports
2.1.
Case 1
A 7-year-old girl was referred to the Department of Pediatric Dentistry at Osaka Dental University Hospital, Osaka, Japan, with a chief complaint of an esthetic problem in the maxillary permanent incisor region. Her medical history was not relevant and there was no family history of dental anomalies. Intraoral examination showed a labial erupted permanent maxillary left central incisor. Also, an erupted supernumerary tooth resembling a miniature incisor was present between the left and right central incisors, and fused to the left central incisor (Fig. 1A and B). The fused tooth had a
85
broad crown and a small groove was observed between the crown of the left incisor and the supernumerary tooth on the labial and palatal sides. The patient had mixed dentition and crowding in the anterior region due to lack of space. Radiographic examination revealed that the maxillary left central incisor had two root canals and two underdeveloped roots (Fig. 1C and D). There was no missing primary or permanent tooth. Computer tomography (CT) images showed that the root canals were not completely separated (Fig. 1E and F). The initial treatment plan was as follows: (1) periodic follow up and checking for pulp separation and development; (2) if there was no connection between the root pulps of the supernumerary tooth and left central incisor, hemisection and extraction of the fused supernumerary tooth; (3)
Fig. 1 e Case 1, first visit. An abnormally wide maxillary left central incisor as a result of fusion between the left central incisor and supernumerary tooth: (A) frontal; and (B) palatal views. The maxillary left central incisor had two root canals and two underdeveloped roots: (C) panoramic radiograph; (D) periapical radiograph. Computed tomography images: (E) horizontal cross-section of root apex; and (F) three-dimensional image of fused teeth.
86
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
reshaping of the left upper central incisor crown through restorative techniques; and (4) alignment and space closure by orthodontic treatment. After 19 months' follow up and monitoring, another regular examination and CT were performed (Fig. 2). The radiograph showed that the roots were separate and nearly fully formed, however, the fused tooth still had a wide-open apex (Fig. 2B). The root canals seemed to be separate as seen in some of the CT images (Fig. 2C and D). Surgical hemisection was scheduled, and the treatment objectives, procedures, the risk of pulp exposure, and alternatives were explained to the patient and her parents. Surgical treatment was performed under local anesthesia 21 months from her first visit to our department. The crown was sectioned using a diamond bur along the mesial side of the groove (Fig. 3A and B). The buccal and palatal flaps were raised, and the conjoint supernumerary tooth including the root was completely removed (Fig. 3C and D). The two teeth were united by enamel, dentin, and cementum, however, the pulp chambers were not involved. Based on these findings, the diagnosis of fusion was confirmed. The mesial portion of the prepared central incisor was reconstructed using the sandwich technique [11]. Glass ionomer cement was used as a base, and composite resin was used for esthetic restoration. Afterward, the flap was repositioned and sutured (Fig. 3E). One week after the operation, wound healing was good and the sutures were removed. The shape of
the tooth crown was also modified using composite resin (Fig. 4A). In order to correct the position of the central incisor, minimal tooth movement was planned. The orthodontic appliance was planned using metal brackets. Following the placement of maxillary brackets, a NieTi arch wire was connected to the bracket slots to correct the upper left central incisor (Fig. 4B). After a 6-month follow-up period, the minimal tooth movement resulted in good esthetics (Fig. 4C and D). The root of the left central incisor formed smoothly. The prognosis of alveolar bone was also satisfactory (Fig. 4EeG).
2.2.
Case 2
A 7-year-old girl was referred to the Department of Pediatric Dentistry at Tokushima University Hospital, Tokushima, Japan, with anterior supernumerary teeth, complaining about malocclusion. The medical and dental histories were not relevant and there was no family history of dental anomalies. Intraoral and radiographic examinations revealed an erupted maxillary central supernumerary tooth (Fig. 5: dotted arrow). Furthermore, radiographic examination of the upper incisors revealed another impacted supernumerary tooth fused with the maxillary right central incisor (Fig. 5A: solid lined arrow). The erupted supernumerary tooth was extracted during her first visit. After several months, the impacted
Fig. 2 e Case 1 at 19 months follow-up and check-up period. (A) Frontal view; (B) periapical radiograph; (C) computed tomography horizontal cross-section image of root apex; and (D) three-dimensional computed tomography image of fused teeth.
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
87
Fig. 3 e Case 1, surgical procedure. Separation of tooth crowns and roots: (A) frontal view; (B) periapical radiograph taken during the operation. Extraction of the supernumerary tooth: (C) postextraction; (D) extracted root of supernumerary tooth; and (E) suture.
maxillary right incisor with supernumerary tooth was surgically exposed (Fig. 5B and C). When the patient was 8 years old, the two roots of the supernumerary tooth and the maxillary right central incisor were almost fully formed and the root dentine and canals were separate as observed in the periapical radiograph (Fig. 5D). Surgical hemisection was performed (Fig. 5E). The hemisection procedure was almost the same as that described for Case 1. In this case, a pulp exposure of size 1 mm 8 mm was noted at the maxillary right central incisor, when the fused teeth crowns were separated (Fig. 5F). Therefore, a partial pulpotomy using calcium hydroxide (Ca(OH)2) as a pulp-capping agent was carried out. Three weeks later, dentin bridge formation was detected at the pulp-capped site, with a temporary seal, Ca(OH)2, and necrotic tissue. The right central incisor was restored using glass ionomer cement and composite resin
(Fig. 6A). A part of the root of the supernumerary tooth remained close to the root of maxillary right central incisor (Fig. 6B). The diastema was closed with minimal tooth movement using the same method of Case 1 (Fig. 6C). Over the past 10 years, no pulp necrosis had become evident in the follow-up observations, and the prognosis of alveolar bone around the root of the maxillary right central incisor and remaining root of the supernumerary tooth was also satisfactory (Fig. 6D and E).
3.
Discussion
Fused teeth may lead to serious esthetic problems, malocclusion, and psychological problems, especially in children and adolescents [12]. Therefore, these problems need
88
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
Fig. 4 e Case 1. (A) One week follow up after the operation; (B) minimal tooth movement; (C, D) after removal of metal brackets. Periapical radiographs: (E) just after the operation; (F) after 5 months; and (G) after 6 months.
immediate attention. Different approaches for the management of fused teeth have been suggested because endodontic, esthetic, orthodontic, periodontal, and functional problems have to be considered. Hemisection is one of the recommended treatments if the fused tooth possesses separate roots [13]. If the pulp chambers are connected, endodontic treatment also becomes necessary. However, the majority of fused teeth are identified when the roots of the teeth are developing. In both present cases, we delayed the hemisection treatment until the roots were fully developed and the pulp chambers were separated. Moreover, whenever pulp exposure occurs in immature teeth with partially developed roots during separation of the fused tooth, it is appropriate to employ a clinical technique which preserves as much vital pulp as possible. This enables continued physiologic dentin deposition and complete root development [14]. In Case 1, based on the presurgical examination results, a conservative treatment option was selected. Extraction of the supernumerary tooth was chosen to solve the esthetic problem and obtain space for alignment. Because no pulp exposure was observed following separation, no endodontic therapy was performed. The sandwich technique [11] using glass ionomer cement and composite resin was used to reconstruct the mesial part of the upper left central incisor. The clinical advantages of this technique include pulp protection, fluoride release, minimum composite
mass, and consequently decreased polymerization shrinkage [15,16]. In Case 2, after separation of the tooth, pulp exposure of the right maxillary central incisor was detected, so that partial pulpotomy using Ca(OH)2 was performed to preserve the vital pulp as much as possible, according to the modified two-step procedure [15]. The advantages of this modified technique compared with the conventional pulpotomy technique are as follows: (1) prevention of inflammatory internal root resorption by removing long-term and chronic pulpal stimulation due to Ca(OH)2; (2) a dead layer between the dentin bridge and lining cement does not form due to removal of the necrotic layer on the dentin bridge; it improves the prognosis of restoration; and (3) the formation of the layer can be observed directly, about 1 month after pulpotomy. Abnormally shaped anterior teeth have an unesthetic appearance due to irregular morphology and crowding problems. The cases reported here both comprised fusion of one maxillary central incisor and a supernumerary tooth. Cetinbas et al. [5] suggested that a reduction of the width of the fused tooth would provide enough space for teeth alignment. However, Kim et al. [12] reported a case in which after hemisection, the abnormally positioned lateral incisor and canine biologically moved to normal positions without orthodontic treatment. In hemisection of fused teeth, the periodontal ligament of the preserved healthy tooth may
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
89
Fig. 5 e Case 2. (A) Periapical radiograph at the first visit. One erupted supernumerary tooth (dotted arrow) and unerupted supernumerary tooth fused to the right maxillary central incisor (solid lined arrow); (B) the fenestration of the impacted maxillary right incisor with the supernumerary tooth; (C) fused tooth started to be erupted; (D) periapical radiograph. It was confirmed that the roots of the supernumerary tooth and maxillary right central incisor were fully formed and the root canals were separated; (E) separation of tooth crowns and roots; and (F) pulp exposure (white arrow).
be lost partly in the same way as replanted teeth after dental trauma or avulsion. A few case reports described postoperative complications, such as hypersensitivity, pulpitis, and external root resorption [17,18]. However, the roots of central incisors in our cases developed favorably and the prognosis of alveolar bone was also satisfactory. Particularly in Case 2, the remaining root of the supernumerary tooth close to the maxillary incisor did not show any periodontal damage over 10 years. It is considered that the roots of
supernumerary teeth and central incisors were fused in the cementum. Based on the present cases, suitable conditions for hemisection of fused teeth are as follows: (1) the root dentine and canals of fused teeth were completely separated; and (2) the cementum of those roots were completely separated or partially combined. Vast knowledge about alternative operative techniques and proper evaluation are required to manage such cases. An
90
p e d i a t r i c d e n t a l j o u r n a l 2 5 ( 2 0 1 5 ) 8 4 e9 1
Fig. 6 e Case 2. (A) Restoration using sandwich technique; (B) periapical radiograph. A part of the supernumerary teeth remained (black arrow); (C) minimal tooth movement. After a 10-year follow-up period: (D) periapical radiograph; (E) panoramic radiograph.
appropriate treatment plan has to be formulated to minimize the risk of any complications.
Conflicts of interest The authors declare that there are no conflicts of interest that could be perceived as prejudicing the impartiality of the research reported.
references
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