Surgical Management of Failed Orthograde Root Filling of Traumatized, Immature, Non-vital Permanent Tooth - A Case Report

INTRODUCTION

Complete asepsis and three dimensional obturation of the root canal system are essential for long term endodontic success. In certain cases such as immature tooth, absence of natural apical constriction creates a challenge. There are a number of protocols to manage such teeth. Traditionally, the customized cone (blunt-end, rolled cone method), the short-fill technique and periapical surgery (with or without a retrograde seal) have been used.Apexification² (apical closure induction), apical barrier technique (one-visit apexification), orthograde root filling using MTA¹ are the more commonly used approaches. The use of triple antibiotic paste², pulp space revascularization³, and apical tissue regeneration⁴ are the more recent treatment modalities used for the same.

However, treatment procedures do not invariably produce the desired results.Periapical lesions, sometimes in conjunction with the clinical symptoms may persist or develop⁵. Earlier, tooth extraction was indicated as a simple and radical method of treating a devitalized, immature tooth with non-responding periapical pathology^6,7. Now, it is widely recommended that the root canal has to be retreated nonsurgically in such conditions. Sometimes, nonsurgical retreatment is not feasible in a situation where tooth with incompletely formed root apex has developed a periapical pathology after orthograde root filling. In such a situation, surgical retreatment is an appropriate alternative⁵. 

Such surgeries have not been popular due to the physical and psychological stress the patient is subjected to⁸, coupled with the perceived inhibition of bone growth⁶. Since very few reports have been published on the subject in children. The present case reports on the surgical management of a periapical lesion which had developed following orthograde root filling in a traumatized, nonvital permanent incisor with incomplete root formation.

CASE REPORT

A 9 year old male child reported to the department of Pedodontics and Preventive Dentistry with the chief complaint of pain and diffuse swelling in the upper front tooth region, accompanied by grade II mobility of the upper right central incisor. There was a history of trauma due to a fall about two months back. On clinical examination, it was found that the child had sustained Ellis class IV injury with fractured incisal edge with respect to upper right central incisor. The periapical radiograph showed incomplete root formation with wide open apex for the same tooth (Fig.1).Emergency endodontic drainage was established and the child was put on Amoxicillin 250 mg TID and non-steroidal anti-inflammatory analgesic Ibuprofen 200mg TID for 3 days.

At the recall visit after 3 days, the tooth was biomechanically prepared minimally after determination of the working length. Formocresol solution on cotton pledgets was used as the dressing material, owing to its strong germicidal properties during the first two visits, at weekly intervals and subsequently replaced by calcium hydroxide paste as intracanal medicament and the patient was recalled after one week.

Patient missed the appointment and returned to the department after one month with history of pain and swelling in relation to the the same tooth. The dressing was removed and canal was debrided and irrigated with a combination of saline and antibiotic, (Amoxycillin) leaving the access cavity open for drainage of the exudate. After successive monthly placement of intracanal medicament CaOH₂ for four months resulted in a clinically asymptomatic tooth, the tooth was obturated with custom fabricated(tailor-made) rolled gutta-percha cone method⁹.

Patient was recalled after a month but returned to the department only following ten months with a draining intra oral sinus with respect to the obturated tooth.Intra oral periapical radiographic examination revealed a well circumscribed periapical radiolucency of 7-8 mm in diameter. (Fig.2). As retreatment could not be effected by orthograde means, a decision was taken to retreat the tooth by surgical approach. The Patient's medical history was noncontributory and written informed consent was obtained from the parents. Patient was prescribed antibiotics to reduce the phase of acute infection. As the child was cooperative, surgical treatment was planned under local anesthesia.

Semilunar incision was made to raise the mucoperiosteal flap, as the periosteum and the over lying bone were perforated, the periapical region was approached by hand instruments with minimal preparation of the bone.Periapical curettage was done with hand curettes to remove the diseased periapical tissue which was sent for histopathologic examination. To facilitate complete removal of the pathologic tissue from the periapical region, apical 1-2 mm of the root and the filling material was smoothened and sealed with hot burnisher and

inspected using a sharp probe to ensure adequacy of the apical seal. Bony cavity was debrided with saline and sharp bony edges were smoothened. A radiograph was taken to ensure a satisfactory operative procedure and for future reference (Fig.3).

The mucoperiosteal flap was replaced and sutured and the patient was discharged after prescribing medications (Amoxicillin 250 mg TID and Ibuprofen 200 mg TID for 3 days) and post surgical instructions. The child was recalled after seven days for suture removal.

The histopathologic section showed connective tissue made up of young delicate collagen fibrils, plump fibroblast, numerous capillaries lined by plump endothelial cells, extravasated RBCs and moderate chronic inflammatory cell infilteration suggestive of periapical granuloma(Fig.4).

In the clinical follow-up at three and six months the patient showed no clinical symptoms and an absence of sinus tract. The radiographic follow-up showed healing of the periapical radiolucency and regeneration of the periradicular tissues (Fig.5).

DISCUSSION

Endodontic management of an anterior tooth with an open apex in young pediatric patients is complex and of varied outcome¹⁰. Management of such a tooth commonly includes calcium hydroxide–induced apical closure (apexification)¹¹, placement of an apical plug of mineral trioxide aggregate (MTA)¹² and, recently, the concept of revascularization.³

Apexification in a nonvital incisor was documented by Kaiser¹³ in 1962 and later popularized by Frank¹¹. Since then, apexification has become the standard treatment protocol for treatment of nonvital immature teeth. Many other materials have been used for apexification including tricalcium phosphate (TCP)¹⁴, collagen calcium phosphate¹⁵ , bone growth factors¹⁶, osteogenic protein¹⁷, but none has truly replaced calcium hydroxide. However, calcium hydroxide–induced apexification has several limitations¹⁸. Apexification performed with Ca(OH)2 is quite time consuming, requiring about 7 to 8 months¹⁹, on an average for apical barrier formation and the time required to achieve apical closure is not reliable and can range anywhere from 3 to 21 months²⁰. Multiple appointments over prolonged treatment time can be frustrating for the patients, which results in more time lost from work, costing the patients parents and the cost of additional treatment and there is also a risk of the patient not returning for follow up appointments, which in turn increases the likelihood of failure.¹⁹ Andreasen and others have shown that long term use of Ca(OH)2 may leave the tooth more prone for fracture due to its hygroscopic²⁰ and proteolytic properties. Dr. Malkhassian, an endodontist at the University of Toronto, suggests that the longer the tooth has been necrotic, the less likely that Ca(OH)2 will lead to apical closure. Such issues with Ca(OH)2 are the reason that new materials may replace Ca(OH)2 as the standard treatment for apexification in the future.

These disadvantages can be avoided by using Mineral trioxide aggregate (MTA) developed at Loma Linda University for use as a root-end filling material.²¹ In 1998, the US Food and Drug Administration approved MTA for use in endodontic procedures.²² Apexification using MTA has several advantages such as, it neither gets resorbed, nor weakens the root canal dentin, and also sets in the wet environment. Satisfactory compaction of obturating material is achievable as MTA on setting provides a sound and hard apical barrier. Few limitations for the routine use of MTA are, its cost factor, the sandy consistency which makes it more difficult to work, does not strengthen the remaining tooth structure.²³

A new regenerative/revascularization treatment option for immature permanent teeth with periapical pathology has been proposed. In these cases, successful revascularization was achieved by disinfection of the necrotic root canal followed by stimulating bleeding into the canal by overinstrumentation. The rationale of this procedure is, if a sterile tissue matrix is provided in which new cells can grow, pulp vitality can be reestablished.^{3, 24-26}Further studies with long-term clinical results are yet to be required in the field of regenerative/revascularization, triple antibiotic paste and tissue engineering concept.

Despite the popularity of these techniques, factors like variability of treatment time, unpredictability of apical closure, difficulty in patient follow-up, susceptibility to fracture, reinfection, cost factor and difficulty in standardization are the factors of concern in the above treatment approaches.

To overcome the shortcomings, initially obturation of wide and divergent apical portion in the present case was done with customized guttapercha cone technique⁹, which is a simple, less time consuming procedure and adapts easily on walls without voids²⁷. But evidenced proportions of root fillings do fail and may manifest clinically and radiologically as in this case. Earlier, such failures warranted extraction of the tooth with all its attendant problems.

In teeth with closed apex an orthograde attempt at retreatment should always be considered first irrespective of the size of the periradicluar lesion (Yeh et al.²⁸ 1999, Steffen & Splieth²⁹ 2000, Pai et al.³⁰ 2004, Subay & Kayatas³¹ 2006) and generally lead to a successful outcome in such cases. But, teeth with open apices do not yield similar success due to the following constraints.

Retreatment by a conventional orthograde approach might lead to fracture of the thin, fragile lateral dentinal walls during retrieval of orthograde root filling and further may not guarantee resolution of the periapical pathology. Endodontic surgery eliminates diseased tissues in the periapical area, facilitates inspection of the apical end of the root filling and ensures that the apical end of the canal is effectively sealed three dimensionally.³²

The surgical intervention in children has been a matter of concern, since the procedure would normally be unpleasant, traumatic, reduces the available length of an immature root and the procedure in the bone might lead to inhibition of growth.If the child is cooperative endodontic surgery can be managed successfully in an outpatient basis under local anesthesia. According to Harnisch growth disturbances have not been noted following periapical surgery in children.³³

According to Kreter and Schonberger, it is sufficient to excochelate the granulation tissue and to smooth the apical region of the root. The high regenerative strength of children assures good results.³³

Schonberger³³ (1966) examined 46 anterior teeth which were followed up for 1-5 years after surgical approach in 10-14 year old children and found that 35% of the teeth were clinically and radiologically without any evidence of disease. Studies published by Grieger³³ demonstrated that the success rate was highest in patients aged 20 years or less and failures were least in this age group.According to Wu and Wesselink, 97% of the lesions including large once of >10 mm in diameter healed completely within 1 year after surgical intervention.³⁴ Zuolo et al³⁵ stated that favourable post-surgical outcomes are possibly affected by the site of surgery as reported to be 97% in maxillary anterior teeth compared to 85% in posterior teeth, which is characteristic for complex radicular anatomy.

The periapical granuloma containing epithelial tissue can be best managed by surgical approach, so that it will not be the basis for cyst formation. Cystic growth has also occurred from encapsulated form of periapical granuloma and the definitive answer to the question of cyst or granuloma is possible only during surgery or finally by histologic examination.³⁶

In situation where, orthograde root filling has failed to prevent the development of periapical pathology in an immature non-vital teeth and further nonsurgical retreatment is non-feasible or may not render better prognosis and for patients who cannot keep recall appointments at long intervals, surgical retreatment is an appropriate alternative. This case report supports that, the periapical surgery of anterior teeth of children is entirely practical promises success in preserving the tooth with poor prognosis and can be considered as Further studies with long term follow up on more number of teeth are required.