|LETTER TO EDITOR
|Year : 2014 | Volume
| Issue : 1 | Page : 41-42
Department of Pedodontics and Preventive Dentistry, The Oxford Dental College and Hospital, Hosur Road, Bomanahalli, Bangalore - 560 068, Karnataka, India
|Date of Web Publication||28-Feb-2014|
Department of Pedodontics and Preventive Dentistry, The Oxford Dental College and Hospital, Hosur Road, Bomanahalli, Bangalore - 560 068, Karnataka
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Subramaniam P. Author's Reply. Saudi Endod J 2014;4:41-2
We are herewith enclosing our response to the queries asked regarding our article titled, ''Revascularization of an impacted, immature dilacerated permanent maxillary central incisor associated with odontoma and a supernumerary tooth.''
Reasons for endodontic intervention - "revascularization"
It is well known that a non-vital young permanent tooth has a wide canal with thin dentinal walls, and the tooth is brittle and more prone to fracture. The immature young permanent maxillary incisor was non-vital with a necrotic pulp. The contents of the canal were extirpated and were found to be necrotic. Due to thin walls, instrumentation of the canal had to be very minimal. Besides irrigation, an antibiotic paste (intra-canal dressing) was given to reduce the infection, prior to the revascularization procedure. This also gave the patient symptomatic relief.
The impacted immature tooth had a dilacerated root and was surgically removed and re-implanted. This situation is similar to an avulsed immature tooth that has its blood vessels severed. Revascularization was done to initiate tissue proliferation, through the open apex, into the canal, with an aim of re-establishing blood supply and tooth vitality. For this purpose, initial bleeding had to be inducted into the canal and the resulting blood clot acted as a scaffold for growth of tissue and blood vessels into the canal. , Scaffolds are used in regenerative procedures to provide a framework through which cells and a vasculature can grow.
When bleeding occurs, mesenchymal stem cells from the bone marrow and periodontal ligament may be transplanted into the root canal. These cells might form bone or a dentin-like tissue. The blood clot that forms is in itself a rich source of growth factors that may play an important role in the regeneration process. These growth factors have the potential to stimulate differentiation, growth, and maturation of fibroblasts, odontoblasts, and cementoblasts. 
During this process, there was a definite thickening of the dentinal walls with concurrent narrowing of the canal space. This can be appreciated on the radiograph, that was taken at 24 months. There was a significant change in canal width, particularly at the apical third, with continued growth and apical closure.
Regenerative endodontics with continued root growth may reduce the risk of fracture and premature tooth loss associated with traditional protocols like ''apexification'' procedures where the root remains short, thin and weak. 
At times it is difficult or impossible to clinically determine the presence of surviving viable cells or to assess the ability of these cells to survive and differentiate. Hypothetically, the longer an infection exists, the lower the probability that pulp and stem cells required for regeneration will survive. 
There is no universal protocol described in the literature, but most depend on the same principles: (1) chemical disinfection of the canal without instrumentation, (2) production of a suitable environment for a scaffold to support tissue in-growth; and (3) a tight bacterial seal of the access opening to prevent the ingress of bacteria. 
According to the American Association of Endodontists, on considerations for clinical regenerative procedures, various regenerative endodontic treatment protocols have been associated with a successful clinical outcome and currently there is no single recommended protocol.  In fact the term "revitalization" was preferred by Lenzi and Trope. According to them, complete understanding for the criteria for predictable revitalization and apexification is still lacking. 
Regenerative endodontic procedures may increase the prognosis of the compromised immature tooth by re-establishment of a functional pulp tissue that fosters continued root development and immune competency. 
| References|| |
|1.||Nosrat A, Seifi A, Asgary S. Regenerative endodontic treatment (revascularization) for necrotic immature permanent molars: A review and report of two cases with a new biomaterial. J Endod 2011;37:562-7. |
|2.||Thomson A, Kahler B. Regenerative endodontics-biologically-based treatment for immature permanent teeth: A case report and review of the literature. Aust Dent J 2010;55:446-52. |
|3.||Shah N, Logani A, Bhaskar U, Aggarwal V. Efficacy of revascularization to induce apexification/apexogensis in infected, nonvital, immature teeth: A pilot clinical study. J Endod 2008;34:919-25; discussion 1157. |
|4.||Wigler R, Kaufman AY, Lin S, Steinbock N, Hazan-Molina H, Torneck CD. Revascularization: A treatment for permanent teeth with necrotic pulp and incomplete root development. J Endod 2013;39:319-26. |
|5.||American Association of Endodontists. Considerations for regenerative procedures. Available from: http://www.aae.org/colleagues Spring 2013. [Last accessed on 2013 Dec 30]. |
|6.||Lenzi R, Trope M. Revitalization procedures in two traumatized incisors with different biological outcomes. J Endod 2012;38:411-4. |
|7.||Law AS. Considerations for regeneration procedures. Pediatr Dent 2013;35:141-52. |