2 TYPES OF INTRAORAL DISTRIBUTION OF FLUOROTIC ENAMEL

Different distributions of fluorotic dental enamel within the dentitio n have been described in the literature. This report describes two pat terns of intraoral distribution. In nine Tanzanian low fluorosis commu nities with a prevalence of pitting fluorosis of less than 2% and in f ive moderate fluorosis communities with a prevalence of pitting fluoro sis of 16-59%, incisors and first molars were the least affected teeth . In four high fluorosis communities with a prevalence of pitting fluo rosis of 86-97%, maxillary incisors exhibited lower Thylstrup-Fejersko v Index values than the maxillary canines, premolars and molars. The m andibular teeth exhibited increasing Thylstrup-Fejerskov Index values from the anterior to the posterior region. The curves presenting the i ntraoral distribution of the severity of dental fluorosis corresponded with the curve presenting the completion time of primary enamel forma tion of the various tooth types, with the exception of the first molar s in high fluorosis communities. The similarity of the curves suggests that the later in life enamel is completed, the higher is the severit y of dental fluorosis. This relation seems to be explained by the prev ailing feeding and dietary habits, which result in minimal intake of f luoride in the first 18 months of life during breastfeeding, followed by increasing fluoride ingestion in the following years through consum ption of tea, seafish and F-containing magadi salt.