| Abstract|| |
Treatment of fused teeth needs special care and attention to the bizarre anatomy. This paper describes root canal treatment of a fused carious tooth presenting with apical periodontitis. It is a rare case of fusion of the mandibular second molar with a paramolar. There is no literature regarding placement of crown over endodontically treated fused teeth. In this case, the fused teeth were endodontically treated and restored by a porcelain fused to metal crown.
Keywords: Developmental anomaly, endodontic treatment, fused teeth, paramolar, supernumerary teeth
|How to cite this article:|
Gupta R, Prakash V, Sharma M. Endodontic and post-endodontic management of a fused molar. Indian J Dent Res 2013;24:274-6
Fusion is a developmental anomaly, which occurs due to a union of one or more adjacent teeth during morphodifferentiation of the dental germs. Fusion may involve the entire length of the teeth, or only the roots, depending on the stage of development of the teeth at the time of union. This is more prevalent amongst primary teeth (0.5%) than amongst permanent ones (0.1%), more often found in the mandible than in the maxilla and in the incisor region. The prevalence for bilateral double teeth is 0.02% in both types of dentition. The crowding of tooth germs; focal growth retardation or focal growth stimulation in certain areas of tooth bud; local metabolic interferences; localized external effects; mechanical blockage of the path of eruption by neoplasms, cysts, supernumerary teeth; vitamin deficiencies; systemic diseases; environmental factors; trauma; inflammatory causes; therapeutic irradiation of the area; orthodontic treatment and a familial tendency have been suggested as a possible cause. An association between double teeth and non-dental congenital deformities such as syndactyly hands, strabismus and nail malformation has been seen.
| Case Report|| |
A 20-year-old female patient with a history of asthma complained of acute continuous pain in the mandibular left posterior region. Clinical examination showed a carious fused mandibular second molar with a supernumerary tooth. The supernumerary tooth was paramolar of conical type [Figure 1]. The fused teeth had separate roots, pulp chambers and root canals. They were fused at the level of dentin in the crown. The periapical radiolucency was visible around the fused tooth in intraoral periapical radiograph [Figure 2]. The tooth gave no response to pulp sensitivity tests (thermal and electric). There was pain on percussion in both molar and paramolar. The diagnosis of pulp necrosis and apical periodontitis was made. Patient was not interested to get the tooth extracted. So it was decided to retain the fused teeth by root canal treatment. The patient was asthmatic and was not ready for the rubber dam isolation. The saliva ejector in conjunction with the absorbents was used. Throat shield was placed and a thread was tied to every intracanal instrument to prevent aspiration and swallowing. Occlusal access cavities were prepared in both mandibular second molar and paramolar. The pulp chamber of molar was large with a visible dentinal map, while the pulp chamber of paramolar was small with a small orifice. All the four canals, three in mandibular second molar and one in paramolar, were biomechanically prepared with stainless steel K-files (Dentsply/DeTrey, Konstanz, Germany) using step-back technique. The mesio-buccal, mesiolingual, distal canal of molar and single canal of paramolar were enlarged to master apical file no. 30, 30, 40 and 40, respectively. The canals were obturated with gutta-percha points and a zinc-oxide eugenol sealer using cold lateral condensation [Figure 3]. The post-obturation restoration was done with silver amalgam in mandibular second molar. The paramolar was conservatively restored with composite resin. The crown reduction was done in both the teeth taking them as a single unit [Figure 4]. The tooth was restored with a porcelain fused to metal crown [Figure 5]. Indirect pulp capping was done in mandibular left first molar in the same visit and it was permanently restored by silver amalgam restoration after 3 weeks. Patient was asymptomatic at postoperative recall visits, i.e. 6 months and 3 years [Figure 6]. However, mandibular first molar showed recurrent caries on distal surface in 3 years, which was restored again.
|Figure 1: Preoperative photograph of the fused teeth showing both the arches in occlusion|
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|Figure 6: Postoperative second recall radiograph of the fused teeth after 3 years|
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| Discussion|| |
Fused teeth often have problems such as dental caries, periodontal disease, poor esthetics, arch-length problems, occlusal interference, displacement of the affected tooth causing deviation and delayed eruption, attrition, irritation of the tongue, loss of space, malocclusion and gingival recession.
For asymptomatic cases, routine review and careful maintenance are required. Fused teeth usually have a vertical groove on the buccal and lingual surface of the teeth, which can be corrected by placing a sealant or composite material into the grooves. Generally, there is communication between root canal systems of fused teeth which should be treated as one entity. Treatment options include extracting the tooth with prosthetic replacement, extraoral or intraoral hemisection and endodontically treating the fusion followed by orthodontic alignment, mesiodistal reduction of the oversized tooth through stripping procedures or surgically removing the redundant part of the tooth only. Surgical division of the double teeth is recommended when the degree of fusion is mild. Teeth that are fused too far apically cannot be sectioned without disturbing a major part of the attachment apparatus on the root to be retained. A multidisciplinary approach may contribute to the success of the treatment.  The operating microscope is a tool for better diagnosis and better quality of care. 
Root canal treatment of fused or geminated teeth has been described by various authors. ,,, But none of them have placed a crown over the endodontically treated fused teeth. Every root canal treated posterior tooth generally needs coronal coverage to protect against fracture from occlusal forces. In the case of fused teeth, placement of crown is difficult. If we place two crowns on fused teeth after separating them, then they will be out of mandibular arch leading to problems of malocclusion. The patient may have problem of cheek biting, accumulation of plaque with periodontal problems. Placement of crown as a single unit over fused teeth is possible after considering both the fused teeth as a single unit and reducing them as a single crown. In this case, the paramolar was small and in the cervical third of the tooth which was not interfering with the occlusion and function. So, both the fused teeth were taken as a unit and crown reduction was done. The paramolar was buccally placed; therefore, buccal surface of the tooth was slightly overreduced to prevent the overcontouring of the buccal surface. Both the teeth were endodontically treated, making the overreduction feasible. Resin cement was used to cement the crown over fused teeth to fill any discrepancy at the fusion interface. A conservative approach that addresses periodontal, pulpal and tooth tissues resulted in the retention of a fused tooth.
| References|| |
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Department of Conservative Dentistry, I.T.S. Centre for Dental Studies and Research, Muradnagar, Ghaziabad, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]