Introduction: Two important growth factors namely transforming growth factor- β (TGF-β) and Insulin-like growth factor (IGF-1) are known to provide protection to dental pulp cells when cultured against the toxicity induced by the composite materials e.g. Durafill VS and Flow Line. Aim: Protective mechanism of IGF-1 and TGF-β is mainly via enhanced endogenous antioxidant activity because the toxicity of composite materials is mainly governed by oxidative stress. The present study was planned to investigate the protective effect of growth factors. Methods: Cultured dental pulp cells were used in current study to determine the mechanism of the protective effects of IGF-1 and TGF-β and their role of cysteine/glutamate exchange (system xc) focusing on the glutathione system. Results: The toxicity of Durafill VS and Flow Line was debilitated by the addition of glutathione monoethylester, suggestive of a specific role of anti-oxidant glutathione. In support of this hypothesis, it was found that IGF-1 and TGF-β had protective effect against the toxic effect of buthionine sulfoximine (glutathione synthesis inhibitor). Cellular cysteine levels are considered to be the limiting factor in glutathione production therefore, effects of IGF-1 and TGF-β were tested on cysteine uptake which were found to stimulate system xc–guided cysteine uptake. Furthermore, they dissipated the glutathione depletion induced by Durafill VS and Flow Line. Conclusions: The results were suggestive of protective role of IGF-1 and TGF- β through system xc– guided cysteine uptake stimulation, leading to maintenance of cellular glutathione. This novel role of growth factors IGF-1 and TGF-β helps in pre-venting toxicity of restorative dental materials and also in the general functioning of dental pulp cells.

Introduction: Imaging is an important diagnostic adjunct in the clinical assessment of the dental patient. Cone beam computed tomography (CBCT) is new innovative imaging modality which provides additional information and low radiation dose than conventional CT, but results in higher radiation doses than conventional imaging procedures such as intraoral and panoramic radiography especially to pediatric patients. Aim: The aim of this review was to compile evidence based clinical trials on effective doses of dental Cone beam computed tomography (CBCT) with focus on measurement methods and compare the effective doses of CBCT, multidetector computed tomography, panoramic radiography and intraoral radiography. This review would also highlight radiation protection measures to be taken while performing CBCT scan. Materials and Methods: The English literature on effective dose of Cone beam computed tomography from October 2000 to January 2019 was reviewed. Data sources included: PUBMED [MEDLINE], SCOPUS, COCHRANE DATABASE, EMBASE and SCIENCE DIRECT. A model was developed to underpin data extraction from 36 included studies. Results: The effective dose showed variations across studies and among CBCT scanners and on average the effective dose ranged from 10 – 425.84 µSv. Exposure from Dental CBCT is lower than conventional CT but it is ten times higher than conventional radiographs (intraoral and panoramic) used in dentistry. In one study, with CBCT effective dose of a 10-year-old phantom was around 116 µSv which was high as compared to adolescent phantoms at 79 µSv. Use of thyroid shielding devices to protect thyroid gland and lead glasses to prevent cataract should be reinforced while performing scan. CBCT scan when performed with use of lead glasses in conjunction with thyroid shielding devices resulted in (42 %) reduction of the effective dose to patient. Conclusion: The review suggests that although, effective dose varies from one CBCT unit to other, it increases with larger Field of View used for scanning. More direct comparison trials are required in future to estimate the effective doses from CBCT and conventional radiographs .Even studies using pediatric phantoms should be encouraged as these patients are at higher radiation risk than adults. During CBCT scanning lead glasses and thyroid collars should be worn by the patients to prevent unnecessary exposure to thyroid gland and lens of eye. CBCT should be used as an additional imaging modality and not as a substitute to conventional imaging. In 2014, new concept emerged in which there was movement from ‘’as low as reasonably achievable’’ (ALARA) to ‘’as low as diagnostically acceptable ‘’(ALADA). Now it’s time to implement this concept into clinical practice.