The role of fluoride on eruption of mandibular molar of albino rats

Eruption of the tooth is a complex and highly regulated process which can be influenced by genetic, environmental and systemic factors. Fluoride is found naturally in water as well as in foods and dental products. The first mandibular molar is the first molar to erupt and it is essential for  mastication of food. We studied the effect of fluoride on the eruption of the first mandibular molar in albino rats. Fluoride at different  concentrations was added to the water of pregnant albino rats while sterile water without fluoride was given to the control pregnant dams. The pregnant dams were allowed to deliver, and the heads of their pups carefully decapitated, and mandibles dissected out on days 10, 12, 15 and 18 for assessment of eruption pattern of the first molar while also measuring the mandibular length and breadth. The mandibles were then processed for hematoxylin and eosin staining. On gross examination, some of the teeth developed intraosseously while others were located mucosally, pre-occlusally or occlusally. There was significant reduction in both the birth weight and mandibular length as the fluoride concentration increased compared to the control but a significant increment in the mandibular breadth between the experimental groups in comparison with the control group on day 15 (p value <0.05). These findings suggest that high concentrations of fluoride could delay mandibular molars’ eruption and also cause low birth weight. Key Words: fluoride, mandibular molar, tooth eruptio

Investigation of the Inhibitive Properties of Alchornea laxiflora leaves on the Corrosion of Mild Steel in HCl: Thermodynamics and Kinetic Study

Staff PublicationThe use of naturally occurring compounds as corrosion inhibitors is of potential interest because of their cost effectiveness, abundant availability and environmental acceptability. Therefore, the study investigates the inhibition efficacy of acid extract of Alchornea laxiflora leaves on mild steel in acidic medium using gravimetric method. Experiments were performed by varying the immersion time, concentration of extract and the temperature. The results showed that acid extract of Alchornea laxiflora leaves is a potential inhibitor for the corrosion of mild steel in acidic medium. The corrosion rate of mild steel in 1M HCl decreases with increase in the concentration of the extract. The inhibition efficiency increases progressively as the concentration of the extract increases but decreases with rise in temperature and the exposure time. The highest inhibition efficiency observed in the presence of the extract was 96 %. Activation energy was found to be 21.81 kJ mol-1 for the blank and increases to 82.57 kJ mol-1 in the presence of the extract. Thermodynamic parameters such as enthalpy change, entropy change and Gibb’s free energy were evaluated. Kinetics of the reaction in the presence of the extracts revealed that it follows a first order reaction and the half-lives increase as the concentration of the extract increases. Adsorption studies revealed that Langmuir adsorption isotherm is the best adsorption model applicable to the adsorption of the extract on mild steel surface. Preliminary investigation of the phytochemical con