|Year : 2012 | Volume
| Issue : 3 | Page : 152-155
Iatrogenic mid-root perforation of fused teeth
Vijay Kumar1, Shipra Arora2
1 Department of Conservative Dentistry and Endodontics, Centre for Dental Education and Research, All India Institute of Medical Sciences, New Delhi, India
2 Department of Periodontics, Maulana Azad Institute of Dental Sciences, New Delhi, India
|Date of Web Publication||30-May-2013|
G-9/10, 2nd Floor, Malviya Nagar, New Delhi
Source of Support: The Case was performed with the help of resources available at Centre for dental for education and research, All India Institute of Medical Sciences, New Delhi, India, Conflict of Interest: None
Fusion is defined as a union between the dentin and/or enamel of two or more distinct dental sprouts that occurs at any stage of the dental organ. Its prevalence ranges from 0.5%-2.5% in the primary dentition alone and 0.1%-1% of the primary as well as the permanent dentition. These fused teeth can cause various problems such as caries, periodontal disease, abnormal eruption, impaction or an ectopic eruption of an adjacent tooth and reported in the literature. However this paper documented an unusual case of iatrogenic root perforation of fused permanent lower anterior teeth during inter maxillary fixation.
Keywords: Fused teeth, fusion, mid-root perforation, trauma
|How to cite this article:|
Kumar V, Arora S. Iatrogenic mid-root perforation of fused teeth. Saudi Endod J 2012;2:152-5
| Introduction|| |
Fusion is defined as a union between the dentin and/or enamel of two or more distinct dental sprouts that occurs at any stage of the dental organ. , The etiology is still unknown; however the influence of pressure or physical forces producing close contact between two tooth germs and necrosis of the intervening tissue has been suggested as one of the reasons. 
The union between the enamel organ and the dental papilla is also shown to have a genetic influence in some of the cases. 
The prevalence ranges from 0.5%-2.5% in the primary dentition alone  and 0.1%-1% of the primary as well as the permanent dentition.  These fused teeth can cause various problems such as caries, periodontal disease, abnormal eruption, impaction or an ectopic eruption of an adjacent tooth. In anterior region, this anomaly results in an unpleasant aesthetics due to abnormal morphology and excessive mesiodistal width, that cause problems with spacing and alignment.  Endodontic or surgical management of such teeth is a challenge.
This paper documented an unusual case of iatrogenic root perforation of fused permanent lower anterior teeth during inter maxillary fixation.
| Case Report|| |
A 31 year old male reported to the Department of Conservative Dentistry and Endodontics (New Delhi, India) with the chief complaint of pain and pus discharge from the labial gingival sulcus around the lower anterior teeth from past 1 year. He had a history of right mandibular body fracture 4 years ago, which was reduced and treated by inter maxillary fixation (IMF). Clinical examination revealed an intraoral sinus with relation to mandibular right central and lateral incisor (tooth #41 and 42). Crowding of lower anterior teeth with fusion between crowns of mandibular left central and lateral incisors (tooth #31 and 32) was noticed [Figure 1].
|Figure 1: Pre-operative clinical photograph revealed a fusion of left mandibular central and lateral incisor|
Click here to view
The intraoral periapical radiograph (IOPA) demonstrated the dentinal union (fusion) between teeth #31 and 32 with single pulp chamber and distinct root canal system and normal periapical architecture. A Mid perforation with periradicular radiolucency around mandibular right lateral incisor (tooth #42) and apical periodontal ligament space widening of mandibular right central incisor (tooth #41) was also observed. An unusual finding on the IOPA was the presence of a well defined circular radiolucency at a mid root level of teeth #31 and 32 with intact pulp canal outline [Figure 2]. Second radiograph with different horizontal angulation revealed a shift in the position of radiolucency. The electric and cold pulp vitality tests elicited a normal response for the fused teeth (#31 and 32) however the teeth #41 and 42 showed no response.
|Figure 2: Pre-operative radiograph with mid root perforation and periapical radiolucency in tooth #42|
Click here to view
The diagnosis of necrotic pulp with chronic apical periodontitis was made for teeth #41 and 42 with mid root perforation in tooth #42. Endodontic therapy was performed under rubber dam isolation and intracanal calcium hydroxide (Prime Dental Products Pvt Ltd., Mumbai, India) was placed for 2 weeks to achieve disinfection. At subsequent visit, orthograde perforation repair in tooth #42 was accomplished with mineral trioxide aggregate (MTA) (ProRoot MTA, Dentsply Maillefer, Ballaigues, Switzerland) under dental operating microscope (Carl Zeiss OPMI PROergo, Oberkochen, Germany) at 16X magnification [Figure 3]. The moist cotton pellet was placed inside the root canal in contact with MTA for 48 hours then removed and the root canal was consequently filled with gutta percha and AH Plus sealer (Dentsply-DeTrey, Switzerland) [Figure 4]. Since the periapical changes were absent with the normal pulp vitality response for the fused teeth (#31 and 32) no treatment was provided.
|Figure 3: (a) Mid root perforation visible under microscope (b) perforation site after repair with MTA|
Click here to view
|Figure 4: Post-operative radiograph after perforation repair and root canal filling|
Click here to view
| Discussion|| |
Root canal perforation is a mechanical or pathological communication between pulp space and periodontium. Internal or external resorption caries, and operator's performance during access and post space preparation are a few common enlisted causes.  In addition; it can also occur due to root damage during mini screw or implant placement. 
Alteration in the protective attachment layer (predent in internally and precementum externally) and the presence of inflammatory process adjacent to the altered root surface are essential for the resorption to take place.  The internal root resorption is generally asymptomatic and diagnosed on routine radiographic examination.  It is a consequence of the injury to predentin and clastic action of osteoclasts and macrophages converted from undifferentiated cells of chronically inflamed but vital pulp.  On the other hand, the external root resorption results from damage to the precementum and inflammation in the adjacent periodontium.  In the absence of stimulation factors, the process is generally self limiting and healing takes place by deposition of new cementum. If the pulp fails to survive the following injury, the necrotic tissue provides a continuous stimulus to sustain the inflammatory and resorptive process.  Both types of resorptions are mainly differentiated based on the radiographic features. Internal root resorption includes the large, round or oval defect, often symmetric in the shape of the ampoule and borders in continuity with the root canal space. , While external root resorption appears as a progressive cavitation with irregular margins in the root and adjacent bone.  Perforation of root surface complicates the diagnosis of internal or external root resorption. The use of parallel radiographic techniques is advocated for differentiating internal from external resorption defects as the defect remains stationary in former with change in angulations of radiograph.  In the present case, a second radiograph taken at a different angle showed the shift in the mid root radiolucency excluded the possibility of internal root resorption. Removal of pulpal tissue is suffice to arrest the internal root resorption while debridement and disinfection of necrotic pulp space with the removal of granulation tissue is essential to check the external resorptive process. ,
Inflammatory root resorption after jaw fractures is rarely reported, but can affect up to 4% of the involved teeth.  The maxillofacial trauma results from an Impact during traffic accidents in daily life or wartime. Indirect damage of adjacent tissues (inferior alveolar blood vessels and nerves, dental pulp tissues, periodontium, etc.) usually accompanies such impact injuries. Transmission effect of the stress waves and tooth concussion might cause a separation of hard and soft tissues (i.e., breakdown of blood vessels passing through apical foramen) resulting in ischemia and ensuing pathological changes in the dental pulp and periapex.  Thus the mid-root perforation in tooth #42 could be attributed to progressive external inflammatory root resorptive process started at the site of iatrogenic precementum damage during intermaxillary fixation.
Irrespective of the cause of perforation (pathologic/mechanical), bacterial infection and persistent periodontal inflammation at the site often leads to treatment failure and eventually the tooth loss. , The successful treatments necessitate infection control and adequate seal on the site. MTA is the current material of choice for perforation repair that has shown good clinical success and was used in the present case. 
Determination of location and extent of perforation site is essential before its repair. Conventional and digital intra oral periapical radiographs are routinely used for endodontic diagnosis and management of the problems. Two dimensional representations of three dimensional anatomies and superimposition of structures limit their diagnostic ability.  Presence of fused teeth further complicates the process. Fusion may be partial or complete with only one pulp chamber dividing into two root canals, as well as two independent endodontic systems or one common pulp canal. Management of this complex pulp anatomy is a challenge to Endodontists and inability to negotiate all the pulp space can lead to treatment failure.  The advanced diagnostic aid such as Cone beam computed tomography are essential as they provides the three dimensional data. Real time images with accurate measurements help in preoperative diagnosis and treatment planning. 
The present case report highlights a possible iatrogenic complication due to fusion of teeth. The vitality of teeth was preserved as they showed dentinal fusion and two distinct root canals. However, the presence of the single wide canal could complicate the situation and create a challenge to Endodontists. Thus when performing inter maxillary fixation, careful evaluation of dentition (clinically and radiographically) is necessary to avoid such impediment.
| References|| |
|1.||Tsurumachi T, Kuno T. Endodontic and orthodontic treatment of a cross-bite fused maxillary lateral incisor. Int Endod J. 2003;36:135-42. |
|2.||Nunes E, de Moraes IG, de Novaes PM, de Sousa SM. Bilateral fusion of mandibular second molars with supernumerary teeth: Case report. Braz Dent J 2002;13:137-41. |
|3.||Shafer WG, Hine MK, Levy BM. Developmental disturbances of oral and paraoral structures. In: A textbook of oral pathology. 4 th ed. Philadelphia, PA: W.B. Saunders; 1993. p. 38-9. |
|4.||Hülsmann M, Bahr R, Grohmann U. Hemisection and vital treatment of a fused tooth-literature review and case report. Endod Dent Traumatol 1997;13:253-8. |
|5.||Kim SY, Choi SC, Chung YJ. Management of the fused permanent upper lateral incisor: A case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;111:649-52. |
|6.||Indra R, Srinivasan MR, Farzana H, Karthikeyan K. Endodontic management of a fused maxillary lateral incisor with a supernumerary tooth: A case report. J Endod 2006;32:1217-9. |
|7.||Sinai IH. Endodontic perforations: Their prognosis and treatment. J Am Dent Assoc 1977;95:90-5. |
|8.||Hwang YC, Hwang HS. Surgical repair of root perforation caused by an orthodontic miniscrew implant. Am J Orthod Dentofacial Orthop 2011;139:407-11. |
|9.||Trope M. Root Resorption due to Dental Trauma. Endod Top 2002;1:79-100. |
|10.||Al-Nazhan SA, Spangberg LW. Light and SEM observation of internal root resorption of a traumatized permanent central incisor. Int Endod J 1995;28:131-6. |
|11.||Singhal A, Gurtu A, Dua K. Endodontic management of internal resorptive defect in maxillary central incisor: A case report. Annal Essen Dent 2010;2:82. |
|12.||Fuss Z, Tsesis I, Lin S. Root resorption: Diagnosis classification and treatment choices based on stimulation factors. Dent Traumatol 2003:19:175-82. |
|13.||Mummery JH. The pathology of pink spots on teeth. Br Dent J 1920;41:301-11. |
|14.||Andreasen FM, Andrasen JO. Textbook and color atlas of traumatic injuries to the teeth. 3 rd edn. St. Louis, MO: Mosby; 1994. p. 563. |
|15.||Andreasen JO, Bakland LK. Pathologic tooth resorption. In: Ingle's endodontics. 6 th ed. Hamilton: BC Decker; 2008. p. 1358-82. |
|16.||Senem YÝÐÝT ÖZER. Diagnosis and Treatment Modalities of Internal and External Cervical Root Resorptions: Review of the Literature with Case Reports. Int Dent Res 2011;1:32-7. |
|17.||Hommez GM, Browaeys HA, De Moor RJ. Surgical root restoration after external inflammatory root resorption: A case report. J Endod 2006;32:798-801. |
|18.||Ren C, Liu R, Tian L, Chen P, Zhou S. An ultrastructural study on indirect trauma of dental pulp caused by maxillofacial impact injury in dogs. Ulus Travma Acil Cerrahi Derg 2006;12:9-16. |
|19.||Tsesis I, Rosenberg E, Faivishevsky V, Kfir A, Katz M, Rosen E. Prevalence and associated periodontal status of teeth with root perforation: A retrospective study of 2,002 patients' medical records. J Endod 2010;36:797-800. |
|20.||Bramante CM, Berbert A. Influence of time of calcium hydroxide iodoform paste replacement in the treatment of root perforations. Braz Dent J 1994;5:45-51. |
|21.||Alsanea R, Ravindran S, Fayad MI, Johnson BR, Wenckus CS, Hao J, et al. Biomimetic Approach to Perforation Repair Using Dental Pulp Stem Cells and Dentin Matrix Protein 1. J Endod 2011;37:1092-7. |
|22.||Rani AK, Metgud S, Yakub SS, Pai U, Toshniwal NG, Bawaskar N. Endodontic and Esthetic Management of Maxillary Lateral Incisor Fused to a Supernumerary Tooth Associated with a Talon Cusp by Using Spiral Computed Tomography as a Diagnostic Aid: A Case Report. J Endod 2010;36:345-9. |
|23.||Ballal S, Sachdeva GS, Kandaswamy D. Endodontic management of a fused mandibular second molar and paramolar with the aid of spiral computed tomography: A case report. J Endod 2007;33:1247-51. |
|24.||Robinson S, Czerny C, Gahleitner A, Bernhart T, Kainberger FM. Dental CT evaluation of mandibular first premolar root configurations and canal variations. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;93:328-32. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4]