Shama Asghar* , AsgharAli** , Saqib Rashid*** , Tasleem Hosein****
Regenerative Endodontics is a new treatment modality that offers a predictable result in teeth with pulpal necrosis and open apex.This case report describes the treatment of a necrotic immature permanent central incisor with crown fracture, in which a regenerative approach was used. Revascularization procedures may provide a more predicable outcome, while rendering mature root formation at the same time.This article describes an ongoing case of revascularization.
open apex, regeneration, revascularization.
The traumatic injury of an immature permanent tooth can lead to the loss of pulp vitality and arrested root development. Because root development takes place for almost 2 years after the tooth has erupted into the oral cavity, an incompletely formed apex is one of the most common features seen in traumatized teeth. The patient commonly reports after many years when necroses of the pulp has caused apical Periodontitis or discoloration, causing either pain or compromised esthetics.
It is difficult to instrument immature canal spaces with conventional endodontic techniques. The open apex is difficult or impossible to seal with conventional root filling methods because of the absence of an apical stop. Furthermore, the arrested development of the dentinal walls at the time of pulp necrosis leaves a weak tooth with thin dentinalwalls that are susceptible to fracture.
Studies on traumatic injuries to immature teeth show promise for revascularization of the root canal system. Under such a scenario, an uninfected necrotic pulp mayact as a scaffold for the ingrowth of new tissue. The key factor for the success of this process in necrotic, infected, immature teeth is disinfection of the root canal system, since it is theorized to be essential to create an environment conducive to revascularization of the root canal system.
The term ‘revascularization’ involves disinfection of the infected root canal using two antibiotics mixture of ciprofloxacin and metronidazole, instead of Ca(OH) . Afterwards, a blood clot is induced, retained, and permanently sealed in the root canal as scaffolding for continuous rootmaturation. The advantages of pulp revascularization lie in the possibility of further root development and reinforcement of dentinal walls by deposition of hard tissue, thus strengthening the root against fracture.Ayoung tooth has an open apex and is short, the pulp is necrotic but usually not infected, so it will act as amatrix into which the tissue can grow The successful regeneration depends on a race between newtissue and bacteria populating the pulp space which is strengthened by the fact that the incidence of revascularization is enhanced if the apex shows radiographic opening of more than 1.1mm. This case report describes an ongoing case of revascularization.
Case Report / TechniquePresenting complaint: A13-year-old girl came in the OPD of Fatima Jinnah Dental Hospital Karachi; she wanted proper alignment of her teeth. She was examined in the Orthodontic department; they sent this patient toOperative department for further evaluation and treatment of her maxillary central incisors. (Figure 1).
Medical history was normal. The dental history disclosed that the patient had suffered dental trauma when she was 9 years old, sustaining a complicated crown fracture of her permanentmaxillary left central incisor.
On extraoral examination, there was no significant finding. Intraoral examination showed , fractured mesial and distal incisal edge of the upper right central incisor. 2/3rd crown of the upper left central incisor was also fracturedwith pulpal involvement.(figure 1)
Wide orifice of the canal was visibly filled with necrotic debris. Patient had no pain, sinus formation in this tooth. Toothwas slightly discolored, andmild tomoderate mal-alignment was present in both the arches. Probing pocket depths were within normal limits vs. adjacent and contralateral teeth. The tooth was diagnosed with a necrotic pulp after testing with warm gutta purcha stick and electric pulp tester.
right central incisor was closed with no pulpal involvement (Figure 2a), the root of left central incisor was immature with open apices, and thin lateral dentinal wall alongwith pulpal involvement. (Figure 2b)
The prognosis of the left central incisor appeared unfavorable because of the combination of the following problems:
1:Fracture of the crown.
3: Immature rootwith open apex.
It was decided that attempting to perform an apexification (and therefore instrumenting the root to length) would seriously compromise the structuralc integrity of the tooth, possibly leading to a split tooth. It was then decided to attempt a pulp regeneration procedure. An informed consentwas taken fromthe patient’s parents.
After dental rubber dam isolation, the root canal was accessed after local anesthetic. It was irrigated with 5.25% sodium hypochlorite with the use of a 27G endodontic irrigation needle (figure 3).
Carewas taken not to allowthe needle to disrupt the apical tissue. Canal was dried with paper points.Acreamy paste of equal proportios of metronidazole (400mg) and ciprofloxacin (500mg) mixed with anesthetic solution was applied to the canal space with a lentulo spiral in a slow-speed handpiece.(Figure no 4). The paste was damped down in the Canal space using the blunt ends of sterile paper points. The access cavity was closed with cotton pellets and intermediate restorativematerial.Second visit:
The tooth was isolated and canal was reopened after local anesthetic. The antibiotic dressing was rinsed from the canal, initially using10 mL of sodium hypochlorite followed by normal saline until the canal was free of debris. The apical tissue was packed; using a sterile file until bleeding filled the canal up to 2 mm below the cementoenamel junction. Frank bleeding was seen (Figure no 5).
The blood column was left to clot for 10 minutes while the canal opening was cleaned with sterile cotton pellets. Access opening was closed with a thick mix of glassionomer (Figure no 6). The tooth was restored with an adhesive composite resin <3>Follow-up evaluation:
At the 6-month follow-up evaluation, the patientwas asymptomatic. Radiographic evaluation showed, no periapical lesion, thickening of lateral dentinal walls and outline of apical closurewas visible (fig 7a).
One year from the time of blood clot induction, the tooth remained asymptomatic. Radiographs revealed normal periapical structureswith continued root development and
Regeneration of tissues rather than replacement with artificial substitutes is an emerging and exciting field in the health science. Revascularization of infected, nonvital, immature teeth can cure the infection and allow continuous root formation is emerging as a new treatment modality for such teeth In the present study, the explanation for this positive outcome is the case selection. The selected Case, had no periapical radioluencywith an immature apex that is open greater than 1 mm in a mesiodistal dimension radiographically. The size of the apical opening must be sufficient to allow ingrowth of vital tissue. Kling suggested that an apical opening greater than 1 mm mesiodistally was associated with successful revascularization of infected, non-vital, immature permanent teeth, while no revascularization occurred in teethwith a smaller apical opening.
Shah N et al documented in their study, a narrowing of the wide apical opening was evident in the majority of cases, thickening of lateral dentinal walls was evident in 57% (8/14) of cases, and increased root length was observed in 71% (10/14) of cases. Wang X and Thibodaux B et al have recently shown in their study that this new root growth is not the normal root structure . The inside wall contains cementum-like tissue called ‘intracanal cementum’, and bone or bone-like tissue called ‘intracanal bone’. Connective tissue similar to the periodontal ligamentwas also present. Astudy about the revitalization approach for managing immature permanent teeth with infected pulp documented that these tissues are not pulp parenchymal tissue . They do not function like a pulp tissue. In this case, infection control was achievedwithminimal instrumentation depending on copious irrigation with 5.25% sodium hypochlorite and the placement of antibiotic paste. The use of a polyantibiotic paste as a root canalmedicament is not new. Grossman proposed the use of a polyantibiotic paste (named PCBS), and an antifungal version with the addition of nystatin (named PCBN). Iwaya et al used an antibiotic paste in the initial visit and Ca(OH)2 during the final visit. Banchs andTrope did not advocate Ca(OH)2 due to its potentially damaging effect on the apical tissue and applied a similar treatment in a case of immature tooth with open apex and sinus tract by applying a mixture of antibiotic paste into root canal system.Sato et al used a mixture of minocycl ine, ciprofloxacin,and metronidazole At 2-year follow-up, there was closure of the apex and thickening of the dentinal walls. Interestingly, the tooth responded positively to the cold test.
The first possible mechanism of positive outcome of revascularization in this case might be due to presence of some vital pulp cells at the apical end of the root canal. These cells might proliferate and differentiate into odontoblasts under the organizing influence of Hertwig’s epithelial root sheath. These odontoblasts can lay down atubular dentin at the apical end causing elongation of root, as well as strengthening and reinforcing of lateral dentinalwalls of the root.
The second possible mechanism could be the presence of stem cells within the apical papilla. They differentiate and proliferate into odontoblasts and deposit tertiary or atubular dentin. The third possible mechanism of root development could be the stem cells from the bone marrow transplanted into canal lumen during instrumentation beyond the confines of the root canal to induce bleeding.
Another possible mechanism of apical closure and thickening of lateral dentinal wall could be the blood clot. The blood clot itself being rich sources of growth factor provides the scaffolding for continued root formation. Besides acting as a physical scaffold, it may also contain other growth factors necessary for protein synthesis and hard tissue deposition like activated platelets. It is believed that the new odontoblastic layer differentiates from stem cells originating from the periodontal ligament.
There are several advantages of revascularization as observed fromthis aswell as fromthe past studies.
1. It is cost-effective, because the number of visit is reduced.
2. Lowest risk of pathogen transmission.
3. Obturation of the canal is not required.
4. It requires a shorter treatment time; after infection control, it can be completed in a single visit.
5. Lowest risk of immune rejection. There are fewlimitations of revascularization.
1. Long term clinical results are as yet not available.
2. Calcification of entire canal, compromising esthetic.
3. Potential risk of necrosis if reinfected.
The materials required for this protocol can be obtained from any pharmacy, and the treatment procedures themselves are less challenging than the more traditional techniques of treating pulpless teeth with open apices. If the attempted revascularization procedure fails, the traditional options of treatment remain, including long-term Ca(OH)2 apexification or MTA apexification followed by a conventional root filling.
This case has been followed for 1 year and we observed that the walls are thickened (and stronger) and the apex has formed normally. The long term outcome of this treatment, is still uncertain. With more clinical evidence and experience, revascularization may become the standard treatment for immature teeth with necrotic, infected pulp.
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