|Year : 2010 | Volume
| Issue : 4 | Page : 288-292
Management of recurrent fracture of central incisor with internal resorption using light transmitting (luminex) post
VS Hariharan1, B Nandlal2, KT Srilatha3
1 Senior Lecturer, Department of Pedodontics & Preventive Dentistry, Sree Balaji Dental College & Hospital, Chennai, India
2 Professor & HOD, Department of Pedodontics & Preventive Dentistry, JSS Dental College & Hospital, JSS University, Mysore, India
3 Associate Professor, Department of Pedodontics & Preventive Dentistry, JSS Dental College & Hospital, JSS University, Mysore, India
|Date of Web Publication||25-Jan-2011|
V S Hariharan
Department of Pedodontics & Preventive Dentistry, Sree Balaji Dental College & Hospital, Chennai
Source of Support: None, Conflict of Interest: None
| Abstract|| |
The normal root canal anatomy may be altered in various pathological processes and making it very difficult and at times impossible to achieve ideal obturation by normal methods. Internal resorption is one among them. There are several treatment protocols advised for this pathological condition. A crown-root fracture is defined as a fracture involving enamel, dentin and cementum and accounts for 5% of all traumatic injuries to the permanent dentition. In anterior teeth, these fractures are usually caused by direct trauma and often complicated in fully erupted teeth. In cases where the fracture line extends down along the long axis of the root, extraction of the tooth is indicated. The purpose of this report is to present the use of light transmitting post system to reinforce the crown root fractured maxillary central incisor due to trauma and internal resorption.
Keywords: Crown root fracture, internal resorption, luminex post
|How to cite this article:|
Hariharan V S, Nandlal B, Srilatha K T. Management of recurrent fracture of central incisor with internal resorption using light transmitting (luminex) post. J Indian Soc Pedod Prev Dent 2010;28:288-92
|How to cite this URL:|
Hariharan V S, Nandlal B, Srilatha K T. Management of recurrent fracture of central incisor with internal resorption using light transmitting (luminex) post. J Indian Soc Pedod Prev Dent [serial online] 2010 [cited 2020 Feb 28];28:288-92. Available from: http://www.jisppd.com/text.asp?2010/28/4/288/76160
| Introduction|| |
The normal root canal anatomy may be altered in various pathological processes and making it very difficult and at times impossible to achieve ideal obturation by normal methods. One such condition is internal resorption which presents as an irregular defect in the rootcanal making that area inaccessible to normal method of cleaning and shaping as well as obturation. In 1998, the American Association of Endodontics  defined internal resorption as "a pathologic process initiated within the pulp space with loss of dentin." Trope and colleagues  described internal resorption as an oval-shaped enlargement of the rootcanal space. Internal resorption is triggered by inflammatory process in vital pulp leading to sequence of events involving odontaclastic activity which causes resorptive defect in root canal. 
Trauma seems to be the initiating factor in majority of cases. Usually, internal resorption is asymptomatic and detectable by routine radiographs. Treatment of internal resorption has included several materials gutta-percha, zinc oxide eugenol and amalgam alloy. These materials do not offer strength to the tooth structure. The introduction of new restorative materials has improved the outcome of these defects, as well as reduced chair time for operators.
A crown-root fracture is defined as a fracture involving enamel, dentin and cementum and accounts for 5% of all traumatic injuries to the permanent dentition.  In anterior teeth, these fractures are usually caused by direct trauma and often complicated in fully erupted teeth. In cases where the fracture line extends down along the long axis of the root, extraction of the tooth is indicated. However, an alternative approach to the extraction of the tooth is to preserve the vital tooth submergence in which the root fragment is retained in situ in order to preserve the alveolar bone until the root can be replaced by an implant. 
The purpose of this report is to present the use of light transmitting post system to reinforce the crown root fractured maxillary central incisor due to trauma and internal resorption.
| Case Report|| |
An 11-year-old boy was referred to the Department of Pedodontics and Preventive Dentistry, JSS Dental College and Hospital, Mysore with a fractured and discolored maxillary left central incisor. [Figure 1] History revealed that patient had a fall 16 months back and the tooth in question was left untreated. A complete radiographic investigation along with routine extra-oral and intraoral examinations was done.
On radiographic examination, the intraoral periapical radiograph revealed an irregular radiolucent area in the central portion of teeth extending from cervical third to middle third of the root which was involving the pulp canal space but not the external surface of tooth. [Figure 2]
It was diagnosed as extensive internal resorption secondary to trauma.Without any further delay, the treatment was initiated. After the isolation of the tooth, access was achieved on the lingual aspect of the crown 21. Care was taken to ensure the complete extirpation of the pulp and accurate determination of the working length with Ingle's method. The canal was instrumented to a size 50 file in apical third using sodium hypochlorite 2.5% as the irrigant. Then Ca(OH) 2 was placed in the rootcanal by using lentulospirals and canal was sealed by double seal (layer of hard setting calcium hydroxide and GIC) and confirmed with radiograph. [Figure 3] and [Figure 4]
Periodic clinical examination was done along with IOPA of the same region. After three months, Ca(OH) 2 dressing was repeated. In review, radiographs showed arrest in the progression of resorption. Thus, the patient was scheduled for the obturation on the next visit.
After four months from the initial visit, patient reported with new trauma [Figure 5]. The clinical and radiographic examination revealed crown root fracture of the same tooth. Though the radiograph did not show the fracture line clearly, clinical examination revealed that fracture line was extending from palatal to buccal side subgingivally [Figure 6]. The crown fragment was mobile but held in place. Patient did not have hemorrhage or swelling in the related area.
As already canal space was filled with calcium hydroxide, it was decided to do the permanent obturation on the same visit. Ca (OH) 2 was completely removed from the canal and obturation was done using the sectional obturation technique. Canal was obturated up to 5 mm from the apex with guttapercha points and apical seal was verified with radiograph [Figure 7].
The choice was made to use the fiber post after the reinforcement of canal walls with composite as they were flared due to the resorptive process. Along with the internal resorption, the crown root fracture made this choice inevitable.
To prepare the canal for composite resin, the tooth was isolated. The canal was irrigated with water, dried with paper points, and etched with gel containing 37% phosphoric acid (3M ESPE, St Paul, MN, USA) for 20 sec. It was again flushed with water and dried of all excess moisture using paper points and an air syringe. Then Dentin-bonding agent was applied to the canal walls and excess was gently removed after each application. The flowable composite resin (Filtek™ Z350® , 3M ESPE, St Paul, MN, USA) was injected slowly into canal space from the apex to the occlusal surface. Care was taken to avoid voids within the canal. Then Luminex® light curing post (Dentatus, USA) was placed in the canal in the centered position and curing was done. The light curing post was then removed with gentle rotational traction leaving behind a reinforced root with a patent size matched post canal. Space for cementing medium was created by using (1.5 mm diameter) Mira fit drill. Matching size 1.5 mm diameter white glass fiber post was selected for adequate length, in which excess was cut using diamond disk. It was then cemented with dual cure cement (Panavia F2.0® , Kuraray America Inc., Houston, TX, USA). During all these procedures, manufacturer's instructions were strictly followed.
The remaining canal space and coronal access of the tooth was then filled with composite resin in two increments and cured. [Figure 8] The lingual surface of the tooth was finished with an ultra fine diamond bur and a composite finishing kit.
The patient received antibiotic coverage, analgesic and 0.2% chlorhexidine gluconate oral rinse for one week in order to avoid probable infection. After a month, probing depth confirmed a normal and healthy periodontium. The crown fracture was built with composite using template method [Figure 9] and [Figure 10].
As the fracture line was extending towards gingivally into alveolar crest around 5mm from the gingival margin, it was decided not to attempt for either surgical crown or orthodontic extrusion lengthening for fracture line exposure.
| Discussion|| |
The suggested contributory factors to internal resorption are trauma, caries, periodontal infections, iatrogenic procedures such as vital pulpotomy and pulp capping, vital restorations, orthodontics, bruxism, anachoresis and radioactive material by different researchers. 
It is believed that internal resorption may occur as an idiopathic dystrophic change in case of unrestored or noncarious teeth. Systemic diseases are not considered to be etiological factors of internal resorption. Internal resorption can be either transient or progressive and affect one tooth or many teeth. Incisors show the highest incidence.
Internal resorption is characterized by resorption of internal aspect of root by multinucleated giant cells adjacent to granulation tissue in the pulp. Chronic inflammatory tissue is common in pulp but causes internal resorption only if odontoblastic layer and predentin are lost or altered. A reason for loss of predentin layer is not obvious but trauma has been suggested as the etiological factor in most cases. 
Prompt endodontic treatment is recommended in all diagnosed cases, because the removal of pulp tissue halts the resorptive process.  Although there is no direct experimental evidence, it may be inferred from other studies that Ca(OH) 2 dressing may help to eliminate the microorganisms and inactivate toxic products which are inaccessible to the initial chemo-mechanical debridement.  Thus, it is considered as an near ideal intracanal medicament in traumatic injuries.
Sodium hypochlorite was used in the first visit for its antimicrobial and dissolving properties against the necrotic pulp tissue. But it is a strong oxidizing agent; it leaves behind an oxygen rich layer on the dentin surface that results in reduced bond strengths, and increased microleakage of the adhesive materials.  Erdemir A et al, in 2004 showed there was no loss of bond strength when chlorhexidine as a medicament.  So sodium hypochlorite irrigation was done in the first visit and chlorhexidine was used in the subsequent visits.
Many authors have shown that long term Ca(OH) 2 as intracranial medicament will lead to the weakening of tooth structure. The loss of dentinal structure, long term Ca(OH) 2 and subsequent trauma could have contributed to the complicated crown root fracture.
In the year 1995, Goodarche recommended that 4 to 5 mm of guttapercha should remain apically to maintain an adequate periapical seal.  Thus 5 mm of apical seal was chosen in this case. The flared canal arising as the result of carious extension, trauma to immature teeth, pulpal pathosis, iatrogenic or endodontic misadventure can cause difficulties to the practicing dentist.
Placements of retentive pins are impossible because of lack of dentinal structure at the cervical portion of the root. The use of conventional tapered cast post would concentrate wedging forces, further stressing the critically weakened coronal end of the post canal. 
According to Chu FC et al, insertion of post is inevitable in cases of total absence of coronal dentin.  Lui advised that when the weakened root is internally rebuilt with suitable adhesive dental materials, the root is dimensionally and structurally reinforced to support and retain a post and core for continued function of the tooth. Therefore, rebuilding the lost dentin with strong dentinal substitute is advisable. Many clinicians have associated the use of composite resin as a reinforcing material. 
Fiber posts are more flexible than the metal posts and have approximately the same modulus of elasticity (stiffness) as dentin. When loaded with resin cement, it was thought that forces would be distributed more evenly in the root.  Good bonding of composite resins to dentin is now possible because of the advances in dentinal adhesives.  So it was decided to use the luminex system which allows the reinforcement of canal walls with composite resin and placement of glass fiber post.
According to Turgut et al, the reattached teeth serve as semipermenant or long-term provisional restorations for children until the tooth and pulp developed to a stage which will allow permanent restoration. Moreover, the reattached tooth is restored with its original contour and margins, thus the periodontal problems tend to be less frequent than those around crown margin. 
In this case, fracture margin in the buccal side was placed subgingivally more than 5 mm, which made the periodontal crown lengthening procedures merely impossible. Orthodontic extrusion was avoided as it should be limited to 5 mm and contraindicated in reattached horizontal fractures. 
This reattachment procedure will allow the normal growth of the alveolar bone till the complete development of maxilla and facial structures. Then the patient can undergo permanent restoration like a single tooth implant which is contraindicated at young age.  This guarded prognosis was informed to the patient and the parent as insisted by many authors.
| Conclusion|| |
This technique by reinforcing the dentinal wall strengthens the remaining tooth structure and also improves the outcome of resorptive defects and reduces operator's chairtime.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10]