Dental Materials
Sherin Johnson; Sameena Begum; SM Laxmikanth; Raghunandan Chunduri; Khadeer Riyaz; Anju Varughese
Abstract
Aim: This study evaluated the effect of physical and chemical sterilization techniques on the fracture resistance of mini-implants.Methods: Thirty-two titanium mini-implants of 1.5 x 8 mm were randomly divided into four groups: control, steam sterilized, dry heat sterilized, and chemically sterilized. ...
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Aim: This study evaluated the effect of physical and chemical sterilization techniques on the fracture resistance of mini-implants.Methods: Thirty-two titanium mini-implants of 1.5 x 8 mm were randomly divided into four groups: control, steam sterilized, dry heat sterilized, and chemically sterilized. The samples were then tested in the air for fracture resistance using a universal testing machine. A tangential load was applied to the head of the mini-implant with a 1 mm/min crosshead speed after blocking each of them in the machine. Also, the maximum load was recorded previous to screw fracture. he Kruskal-Wallis test and Mann-Whitney post hoc test were used for data analysis.Results: The results of this study demonstrated the mean fracture resistance difference between the four groups was statistically significant at p<0.001. Moreover it was showed the control group had significantly higher mean fracture resistance compared to dry heat and chemically sterilized groups at p=0.001 and p=0.009 respectively. This was followed by the stem sterilized group demonstrating significantly higher mean fracture resistance as compared to dry heat and chemically sterilized groups at p=0.001 and p=0.01 respectively. Later, the chemically sterilized group also showed significantly higher mean fracture resistance as compared to the dry heat group at p=0.002. However, no significant difference was observed between the control and stem sterilized groups (p=0.29).Conclusion: The steam sterilized group demonstrated the highest fracture resistance that was followed by the chemically sterilized group, and the least with the dry heat sterilized group.
Orthodontics
Nausheen Eram; SM Laxmikanth; Raghunandan Chunduri; Sameena Begum; Khadeer Riyaz; Ashita Talwar
Abstract
Aim: Metallic corrosion of orthodontic appliances occurs due to potentially damaging physical and chemical agents. The major corrosion products of stainless steel are iron, chromium, and nickel. When tissues are exposed to certain concentrations of a primary irritant for certain periods, cytotoxic effects ...
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Aim: Metallic corrosion of orthodontic appliances occurs due to potentially damaging physical and chemical agents. The major corrosion products of stainless steel are iron, chromium, and nickel. When tissues are exposed to certain concentrations of a primary irritant for certain periods, cytotoxic effects may be observed. Hence, this study aimed to assess the cytotoxicity of nickel, iron, and chromium ions during fixed orthodontic treatment onto human keratinocytes (HaCaT).Methods: The metal ions nickel, chromium, and iron in concentrations of 75, 150, 300, 600, 1200, and 2400 μg/ml were prepared to assess the cytotoxicity on HaCaT cells. The control group included these metal ions at 0 μg/ml. Cytotoxicity was assessed by microculture tetrazolium (MTA) assay. The half maximal inhibitory concentration (IC50) was measured and a scanning electron microscope (SEM) was used to assess the morphological changes of the HaCaT cells. The Kruskal-Wallis test followed by the Bonferroni’s post hoc test was carried out to determine the difference in percentage inhibition within and between the groups at various concentrations.Results: Nickel showed the highest cytotoxic effects in comparison with other metal ions. Iron hexahydrate, nickel hexahydrate, and chromium hexahydrate have shown an IC50 value of 552.4 μg/ml, 364.1 μg/ml, and 641.1 μg/ml inhibition in HaCaT cells respectively. Cytotoxic effects were dose dependent on the tested materials. Comparison of percentage inhibition between groups showed a p-value of 0.372.Conclusion: The present study showed that the nickel, chromium, and iron ions induced a wide range of toxicity to human keratinocytes. The IC50 values ranged between 364.1 and 641.1. Nickel was the most toxic metal tested between the concentrations of 75 to 2400 μg/ml for HaCaT cells compared to other metal ions used in the study.
Orthodontics
Somasundara Ramadevi; Anjith Shirley Gladstone; Sarala Manjappa Laxmikanth; Chunduri Raghunandan; Jairaj Vani; Shrikanth Shendre; Khan Mahamad Irfanulla; Maqbool Sameena Begum; Riyaz Khadeer
Abstract
Aim: The use of pre-procedural mouth rinse for prevention of COVID-19 can reduce viral load but can alter the bond strength. The purpose of this study was to determine any correlation between the use of these pre-procedural mouth rinse and the shear-bond strength (SBS) of orthodontic brackets.Methods: ...
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Aim: The use of pre-procedural mouth rinse for prevention of COVID-19 can reduce viral load but can alter the bond strength. The purpose of this study was to determine any correlation between the use of these pre-procedural mouth rinse and the shear-bond strength (SBS) of orthodontic brackets.Methods: Thirty-three maxillary premolars extracted for orthodontic purposes were used. The buccal surfaces of all teeth were bonded with orthodontic brackets. Later, each tooth was embedded into acrylic resin and stored in distilled water. Teeth were randomly divided into three groups (group I: hydrogen peroxide mouth rinse, group II: povidone-iodine mouth rinse, and group III: artificial saliva), and stored in each solution for 12 hours. Later, each tooth was subjected to SBS testing using a universal testing machine. Data were statistically evaluated using one-way analysis of variance (ANOVA) and post hoc test (Tukey’s HSD) with a significance of p< 0.05.Results: The highest mean SBS was observed in the artificial saliva (control group), followed by the povidone-iodine and hydrogen peroxide groups.Conclusion: Hydrogen peroxide mouth rinses should not be used during fixed orthodontic treatment because it alters bond strength.