In this research miswak leaves, agriculture wastes, available in large quantity in Saudi Arabia, was used as low-cost adsorbent for removing methylene blue (MB) dye. Equilibrium behavior of miswak leaves was investiga...In this research miswak leaves, agriculture wastes, available in large quantity in Saudi Arabia, was used as low-cost adsorbent for removing methylene blue (MB) dye. Equilibrium behavior of miswak leaves was investigated by performing batch adsorption experiments. The effects of [MB] 0, pH, contact time and adsorbent dose were evaluated. An alkaline pH (10.6) was favorable to the adsorption of MB dye. Adsorption isotherm models, Langmuir, Freundlich and Temkin were used to simulate the equilibrium data. Langmuir equation was found to have the highest value of R2 compared with other models. Furthermore, it was found that miswak leaves have a high adsorptive capacity towards MB dye (200 mg/g) and show favorable adsorption of MB dye with separation factor (RL < 1). In addition, pseudo-first- order, pseudo-second order and intra-particle diffusion were used to study the kinetics of MB adsorption onto miswak leaves. Adsorption process undergoes pseudo-second order kinetic as proved by the high value of R2 and the low value of sum of squared error (SSE percentage). Results indicated that intra-particle diffusion is not the limiting step, and the adsorption process is spontaneous as indicated by the negative value of the .展开更多
Understanding the effects of enamel loss and surface softening caused by acidic soft drinks consumption would help in the clinical treatment of tooth wear and aid in the development of novel dental restorative materia...Understanding the effects of enamel loss and surface softening caused by acidic soft drinks consumption would help in the clinical treatment of tooth wear and aid in the development of novel dental restorative materials. Hence, this investigation was car-ried out to examine the effects of “Miswak” on the acid eroded enamel surface at nano-mechanical scale. The first use of a stylus-based inductive gauge is introduced as means of measurement of acid attack on enamel surfaces and the effectiveness of aqueous extracts of Salvadora persica as dissolution inhibitors for acid eroded enamel surfaces. For pre-molar protective, after being exposed to aqueous extracts of Salva-dora persica solution, the performance of the enamel surface was improved by R<sub>a</sub> ≈ 0.82 μm. Whereas, the surface was damaged after immersing in citric acid solution by R<sub>a</sub> ≈ 0.63 μm. For pre-molar restoring, the enamel surface was degraded by R<sub>a</sub> ≈ 0.34 μm when exposed to citric acid solution. While, the surface roughness was improved by R<sub>a</sub> ≈ 0.95 μm when aqueous extracts of Salvadora persica solution was introduced. So, this study concludes that the aqueous extracts of Salvadora persica treatment work effectively on the eroded enamel surface.展开更多
The rate of dental caries and periodontal diseases in the world is still high, regardless of progress in the oral and dental hygiene. The natural toothbrush or chewing stick called “Mis- wak” has been used since anc...The rate of dental caries and periodontal diseases in the world is still high, regardless of progress in the oral and dental hygiene. The natural toothbrush or chewing stick called “Mis- wak” has been used since ancient history. In this research the efficacy of Miswak in preventing dental caries was investigated and compared with the efficacy of toothbrush and tooth- paste. The analytical and clinical trial method was applied for this research among high sch- ool’s students in the city of Yazd, Iran, 2006. Three hundred eighty second year’s students (190 cases and 190 controls) were examined dentally. Then the Miswak was distributed to the case group and required trainings were given to both groups. After one year, the examinations were repeated. For analyzing the data one-way variance analysis test, Kai square, Paired t-test and two variable analyses were used. In the beginning of this study, there were no significant differences between two groups (cases and controls) regarding their dental situation and the frequency of brushing their teeth (p-value = 0.162). In addition, there were no significant differences in DMFT between the two groups. The data collected at the end of the study showed a significant increase in DMFT in the control group (p-value = 0.000). There was 55% increase in the rate of dental caries in control group compared to case group (0.89 before the study and 1.38 after the study). The risk of dental caries for each tooth in control group was 9.35 times more than case group (9.14% and 0.98% respectively). Dental caries rate was detected slightly less in the case group at the end of this study. This might be as a result of the antimicrobial effects of Miswak. A longer study with more cases is needed to prove this suggestion.展开更多
文摘In this research miswak leaves, agriculture wastes, available in large quantity in Saudi Arabia, was used as low-cost adsorbent for removing methylene blue (MB) dye. Equilibrium behavior of miswak leaves was investigated by performing batch adsorption experiments. The effects of [MB] 0, pH, contact time and adsorbent dose were evaluated. An alkaline pH (10.6) was favorable to the adsorption of MB dye. Adsorption isotherm models, Langmuir, Freundlich and Temkin were used to simulate the equilibrium data. Langmuir equation was found to have the highest value of R2 compared with other models. Furthermore, it was found that miswak leaves have a high adsorptive capacity towards MB dye (200 mg/g) and show favorable adsorption of MB dye with separation factor (RL < 1). In addition, pseudo-first- order, pseudo-second order and intra-particle diffusion were used to study the kinetics of MB adsorption onto miswak leaves. Adsorption process undergoes pseudo-second order kinetic as proved by the high value of R2 and the low value of sum of squared error (SSE percentage). Results indicated that intra-particle diffusion is not the limiting step, and the adsorption process is spontaneous as indicated by the negative value of the .
文摘Understanding the effects of enamel loss and surface softening caused by acidic soft drinks consumption would help in the clinical treatment of tooth wear and aid in the development of novel dental restorative materials. Hence, this investigation was car-ried out to examine the effects of “Miswak” on the acid eroded enamel surface at nano-mechanical scale. The first use of a stylus-based inductive gauge is introduced as means of measurement of acid attack on enamel surfaces and the effectiveness of aqueous extracts of Salvadora persica as dissolution inhibitors for acid eroded enamel surfaces. For pre-molar protective, after being exposed to aqueous extracts of Salva-dora persica solution, the performance of the enamel surface was improved by R<sub>a</sub> ≈ 0.82 μm. Whereas, the surface was damaged after immersing in citric acid solution by R<sub>a</sub> ≈ 0.63 μm. For pre-molar restoring, the enamel surface was degraded by R<sub>a</sub> ≈ 0.34 μm when exposed to citric acid solution. While, the surface roughness was improved by R<sub>a</sub> ≈ 0.95 μm when aqueous extracts of Salvadora persica solution was introduced. So, this study concludes that the aqueous extracts of Salvadora persica treatment work effectively on the eroded enamel surface.
文摘The rate of dental caries and periodontal diseases in the world is still high, regardless of progress in the oral and dental hygiene. The natural toothbrush or chewing stick called “Mis- wak” has been used since ancient history. In this research the efficacy of Miswak in preventing dental caries was investigated and compared with the efficacy of toothbrush and tooth- paste. The analytical and clinical trial method was applied for this research among high sch- ool’s students in the city of Yazd, Iran, 2006. Three hundred eighty second year’s students (190 cases and 190 controls) were examined dentally. Then the Miswak was distributed to the case group and required trainings were given to both groups. After one year, the examinations were repeated. For analyzing the data one-way variance analysis test, Kai square, Paired t-test and two variable analyses were used. In the beginning of this study, there were no significant differences between two groups (cases and controls) regarding their dental situation and the frequency of brushing their teeth (p-value = 0.162). In addition, there were no significant differences in DMFT between the two groups. The data collected at the end of the study showed a significant increase in DMFT in the control group (p-value = 0.000). There was 55% increase in the rate of dental caries in control group compared to case group (0.89 before the study and 1.38 after the study). The risk of dental caries for each tooth in control group was 9.35 times more than case group (9.14% and 0.98% respectively). Dental caries rate was detected slightly less in the case group at the end of this study. This might be as a result of the antimicrobial effects of Miswak. A longer study with more cases is needed to prove this suggestion.
