White mineral trioxide aggregate mixed with calcium chloride dihydrate: chemical analysis and biological properties

OBJECTIVES: This study aimed to evaluate the chemical and biological properties of fast-set white mineral trioxide aggregate (FS WMTA), which was WMTA combined with calcium chloride dihydrate (CaCl₂·2H₂O), compared to that of WMTA. MATERIALS AND METHODS: Surface morphology, elemental, and phase analysis were examined using scanning electron microscope (SEM), energy dispersive X-ray microanalysis (EDX), and X-ray diffraction (XRD), respectively. The cytotoxicity and cell attachment properties were evaluated on human periodontal ligament fibroblasts (HPLFs) using methyl-thiazol-diphenyltetrazolium (MTT) assay and under SEM after 24 and 72 hours, respectively. RESULTS: Results showed that the addition of CaCl₂·2H₂O to WMTA affected the surface morphology and chemical composition. Although FS WMTA exhibited a non-cytotoxic profile, the cell viability values of this combination were lesser than WMTA, and the difference was significant in 7 out of 10 concentrations at the 2 time intervals (p < 0.05). HPLFs adhered over the surface of WMTA and at the interface, after 24 hours of incubation. After 72 hours, there were increased numbers of HPLFs with prominent cytoplasmic processes. Similar findings were observed with FS WMTA, but the cells were not as confluent as with WMTA. CONCLUSIONS: The addition of CaCl₂·2H₂O to WMTA affected its chemical properties. The favorable biological profile of FS WMTA towards HPLFs may have a potential impact on its clinical application for repair of perforation defects.

A survey on light intensity outputs of QTH, cabled and cordless LED light curing units

Light intensity output is one of the determinants for adequate curing of visible light-cured materials. The aim of this survey was to evaluate the light intensity outputs (LIOs) of light curing units (LCUs) in dental clinics of Hospital Universiti Sains Malaysia (HUSM) and School of Dental Sciences, Universiti Sains Malaysia (USM). The respective LIOs of all functioning Quartz Tungsten Halogen (QTH) and Light Emitting Diode (LED) LCUs were tested using two light radiometers. For cordless LED LCUs, the testing procedure was done in situ and after being fully charged. Statistical analysis using Kruskal Wallis and Wilcoxon signed ranks tests were performed to compare the LIOs between groups and between the LIOs of in situ and post-charged cordless LED LCUs, respectively. The level of significance was set at 0.05 (p<0.05). The results revealed that 72.72%, 42.47% and 92% of QTH, cabled LED and cordless LED LCUs exhibited acceptable LIOs, respectively. Data analysis using Kruskal Wallis test showed a statistically significant difference between groups (p<0.05). The intergroup comparisons using multiple Mann Whitney test with Bonferroni correction revealed a significant difference between the LIOs of cordless LED and both QTH and cabled LED (p<0.017). The difference between the LIOs of in situ and post charged cordless LED LCUs was also significant (p<0.05). In conclusion, both QTH and cordless LED LCUs performed better in term of LIOs than cabled LED LCUs. Periodic testing of LCUs is essential to ensure optimal performance.

Comparison of over flared root canals of mandibular premolars filled with mta and resin-based: an in-vitro

The aim of this study was to compare the fracture resistance of over-f/ared root canals of teeth obturated with either MTA or Composite. 104 human extracted lower single rooted premo/ars teeth were allocated, 13 sample were used as positive control group [Group+ve], while the remaining 92 teeth were prepared to the working length, and subsequently over flared, leaving the apical 5mm undisturbed, and randomly allocated into 7 groups of 13 samples each. Negative control group [Group-vej were over prepared and left without obturation, while the remaining 6 groups were obturated with gutta percha-nano HA [Group 1], gutta percha-nano HA + composite [Group 2], gutta percha-nano HA + MTA [Group 3], resilon-epiphany [Group 4], resilon-epiphany + composite [Group 5], and resilon-epiphany + MTA [Group 6] Fracture resistance of all the samples in each group were measured using the Instron machine [Instron 5982, IDR, UK] while 3 samples from each group had the depth of their fracture line measured by Micro CT Scan [Gemini, LEO SUPRA 55VP, Germany]. This In-Vitro study showed that the highest fracture resistance was observed in Group H-ve, followed by Group 3, Group 6, Group 5, Group 4, Group 2, Group 1 with the value of 1721.7[219.6] 1498.5[260.3], 1432.6[205.3], 896.5[59.9], 784.6[154.8], 761.2[303.8], 474.5[262.8] respectively. The lowest fracture resistance was Group-ve, 286.6[80.7]. Statistically, there was a highly significant difference in fracture resistance between all groups P value < .001. Micro CT Scan showed that tooth in the Group +ve has the lowest percentage of tooth fracture. Within the limits of this study, it is concluded that MTA has the ability to withstand heavy vertical forces