Epidemiological study of odontogenic tumours: An institutional experience.

Epidemiological studies on odontogenic tumours conducted in different parts of the world emphasised variation in incidence and distributional pattern. Such epidemiological studies are obscured in Southern state of Andhra Pradesh in India. Present study was conducted at an institutional setup in South Indian population to assess the demographic data of odontogenic tumours. The retrospective study, which included all the odontogenic tumours from the archives of department of oral pathology, Dental teaching and Research Institution in southern part of India. Cases were selected based on the classification of WHO 2005 histopathological typing for odontogenic tumours and the assessment year considered was from 2002 to 2014. Demographic data was analysed for these tumours. Results were analysed using Chi-Square Test. Incidence of the odontogenic tumours was found to be 2.17%. Peak age incidence was recorded highest in third and fourth decade of life. Males were commonly involved [59%] with the male to female ratio of 1.43:1. Posterior mandible [53.4%] was the chief anatomical location involved with the tumours. Considering the individual lesions, Ameloblastoma [49%] was found to be more frequent, followed by Keratinizing cystic odontogenic tumour [32%], Odontome [6.2%], Adenomatoid odontogenic tumour [5.5%], Odontogenic myxoma [2.4%], Ameloblastic fibroma [0.6%], Calcifying epithelial odontogenic tumour [1.8%] and Squamous odontogenic tumour [1.2%]. The total frequency of odontogenic tumours was 2.17%. Ameloblastoma and Keratinizing cystic odontogenic tumours were the predominant tumours, demonstrating significant regional and geographic variation.

XMCD studies of thin Co films on BaTiO3.

Different layer thicknesses of cobalt ranging from 2.6 Å (1.5 ML) up to 55 Å (30.5 ML) deposited on ferroelectric BaTiO3 have been studied regarding their magnetic behavior. The layers have been characterized using XMCD spectroscopy at remanent magnetization. After careful data analysis the magnetic moments of the cobalt could be determined using the sum rule formalism. There is a sudden and abrupt onset in magnetism starting at thicknesses of 9 Å (5 ML) of cobalt for measurements at 120 K and of 10 Å (5.5 ML) if measured at room temperature. Initial island growth and subsequent coalescence of Co on BaTiO3 is suggested to explain the sudden onset. In that context, no magnetically dead layers are observed.