Tehran University Medical Journal

Herbal essential oils are volatile, natural, complex compounds formed by medicinal plants as secondary metabolites. As reported by international organization for standardization (ISO), the term "essential oils" (EOs) is defined for a product obtained from vegetable raw materials or fruit using distillation with water or steam. The EOs are generally complex mixtures of volatile organic compounds include hydrocarbons (terpenes and sesquiterpenes) and oxygenated compounds (alcohols, esters, ethers, aldehydes, ketones, lactones, phenols, and phenol ethers) compounds. In medicinal plants, the EOs chemical profile usually very varies because of both intrinsic (sexual, seasonal, ontogenetic, and genetic variations) and extrinsic (ecological and environmental aspects) factors, also the EOs composition differs not only in the number and type of molecules but also in their stereochemical structures, and can be very different according to the extraction method. EOs represents a “green” alternative in the nutritional and pharmaceutical fields due to reported antimicrobial, antioxidant, anti-inflammatory and anticancer properties thus, in recent times; EOs has gained great popularity as consumers have developed a particular ever-growing awareness toward the use of natural ingredients, especially in food and household. Therefore, the present review provides a comprehensive summary on the method of preparation of EOs from medicinal plants, chemical composition analysis, their biological and pharmacological effects and their potential benefits on health level. Present information was compiled using keywords “Essential oil, Medicinal Plants and Natural additive in scientific database as Science Direct, Elsevier, PubMed, Google scholar and SID, until 2005 to 2015. EOs have great antimicrobial activity and mostly destroy bacteria, fungi and viruses without harmful effects on consumer’s health. Finding of this study showed that the Thymol, α-Pinene, β-Pinene, Cumin Aldehyde, Carvacrol, Germacrene, Linalool were the main components. Also, EOs have antioxidant, anti-inflammatory and many other pharmacological properties which enhance their potential application. EOs have potential biological and pharmacological activities and so have many applications in pharmaceutical and food industries.

Background: The mandibular first molar teeth are the most common teeth that undergo endodontic treatment and are anatomically very challenging. Adequate knowledge of the danger zone in the mesial root of the first mandibular molars helps reduce the risk of misdiagnosis of perforation during treatment. The aim of this study was to compare the dentin thickness of the danger zone in the mesial canals of the mandibular first molar in CBCT(Cone Beam Coomputed Tomography) images at intervals of 3, 4, 5 mm below the orifice canal.
Methods: In this study, CBCT images of 144 mandibular first molars from 74 patients aged 18 to 66 years were examined. Mean orifice to Furcation was calculated and mean distal dentin thickness of mesiobuccal and mesiolingual canals was measured at 3, 4 and 5 mm below the orifice. The mean thickness of the distal dentin was examined in terms of age, sex and maxillary side.
Results: The lowest mean distal wall thickness of mesiobuccal and mesiolingual canals was 5 mm below the orifice of the canal. The mean distal wall thickness of mesiobuccal and mesiolingual canals were higher in men than women (P <0.05). The mean distal wall thickness did not show a significant relationship with age. (P=0.745) except in the area of 3 and 5 mm below the orifice in the mesiobuccal canal which was significantly associated with age (P=0.01). No statistically significant difference was observed between the two mandibular sides (P=0.543) except in the 4 mm area below the orifice in the mesiolingual canal (P <0.05).

Conclusion: The present study showed that the danger zone is observed in the distal dentin of the mesiobuccal and mesiolingual canals of the mandibular first molar teeth in men and women 5 mm below the orifice of the canal. The mean dentin thickness of the distal wall was lower in women than in men.