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Regenerative endodontics has become a revolutionizing tissue engineering concept in the treatment of immature permanent teeth for over two decades. It has been described as a ‘paradigm shift’ in the treatment of immature teeth, since it fosters continued root maturation. An immature necrotic permanent tooth is usually a result of trauma or infection due to which the tooth becomes non-vital before completing root development. In such cases, the root walls are left thin and weak with an open apex. Traditional apexification procedures may resolve pathology but have not been able to prove tooth survival due to absence of continued root development and risk of root fracture. A successful regenerative endodontic procedure (REP) results in resolution of signs and symptoms of pathology, radiographic signs of healing, proof of continued root development as well as presence of pulp vitality due to the regeneration of pulp tissue in the root canal. Various stem cells, growth factors, scaffolds and suitable environment form the tetrad of elements necessary to induce regeneration of dental pulp. While there has been some success in isolating dental pulp cells with in-vitro experiments, it has been proven to be rather difficult to implement the same in a practical perspective ex vivo. Although there has been clinical success related to REP, histologically they seem to undergo guided endodontic repair rather than true regeneration of physiologic pulp tissue. This review provides an overview of components of tissue engineering, clinical protocol and predictable outcomes for REP and recent advances in regenerative dentistry.

Introduction: Amalgam has been the restoration of choice for years, but its popularity has declined due to concerns about aesthetics, mercury toxicity and lichenoid lesions associated with it. Lichenoid reaction is considered to be a delayed hypersensitivity type of reaction and it has been associated with dental materials in general and amalgam in particular. Materials and Methodology: Two thousand patients having at least one amalgam restoration were examined for signs of lichenoid lesions when visiting the OPD of Conservative Dentistry and Endodontics at the Nair Hospital Dental College in Mumbai, India. Indirect spatial correlation to the amalgam restoration and the same were recorded. Descriptive analysis was used. Results: Three (0.15%) out of 2000 patients with amalgam-associated lichenoid lesions showed complete resolution of lesions after the replacement of the restorations. Conclusion: Amalgam associated lichenoid lesions have a low prevalence and should not be a contraindication to its use in routine restorative dental practice. Patch tests and biopsies have questionable diagnostic and prognostic value. Identification of the lesions should be made after the elimination of all other causative factors for the presenting symptoms. A close spatial association of the lesion to amalgam and the regression of symptoms after its removal should be considered as confirming the diagnosis.

The cyclic fatigue, torsional resistance, and angular deflection of a new Fire-Wire rotary file (CricENDO) were compared. A total of 20 files of each type were tested. Cyclic fatigue testing was performed for each group (n = 10) by measuring the number of cycles to fracture (NCF) in an artificial stainless-steel canal (60° angle of curvature, with a 6-mm radius) for each group. The torque and angle of rotation at the failure of each group (n = 10) were measured according to ISO 3630-1. The fractured surfaces were examined using scanning electron microscopy. Statistical analysis was carried out utilizing Student’s t-test at a significance level set at 5%. The Fire-Wire CricENDO rotary files were associated with a significantly higher number of cycles to fracture and time to failure (in seconds) compared to the M-Wire Protaper Next (p < 0.05). A significantly higher angular deflection to fracture was observed for CricENDO compared to Protaper Next (p < 0.05). The new Fire-Wire CricENDO rotary files exhibit higher cyclic fatigue resistance and angle of rotation to fracture than M-Wire Protaper Next. Without warning, file fracture may occur as a result of cyclic fatigue, torsional stress, or a combined effect of both. CricENDO rotary files may be an effective alternative in curved root canals as they exhibited elevated cyclic and torsional resistance. It will be helpful in eliminating one of the reasons for file fracture during the root canal treatment.