Timing of deciduous teeth emergence in Egyptian children

The existing eruption schedules for permanent and deciduous dentition are based on studies in industrialized countries. This study determined the dates of emergence of deciduous teeth in a cross-sectional sample of 1132 Egyptian infants aged 4-36 months selected from different governorates of Egypt. The dates of emergence of individual teeth were calculated using Probit analysis. The mandibular left and right incisors were the earliest teeth to emerge at a mean of 8,0 months in boys and 7.9 months in girls. The sequence of eruption followed atypical pattern. The average time from emergence of the first tooth to the last tooth was 17.8 months in the mandible and 15.8 months in the maxilla for boys and 22.1 and 20.1 months respectively for girls. Four active phases of emergence were identified and compared with data from other countries

Evaluation of using potassium pyroantimonate in retention of 45Ca in enamel and dentine forming cells

To evaluate the effect of potassium pyroantimonate [PPA] on the retention and localization of [45]Ca in both ameloblasts and odontoblasts, six frogs were injected with 5uci/gm body weight of [45]CaCl[2]. Pairs of the animals were sacrificed 5 min, 1 h and 24 hs post injection. Blocks of the developing teeth were dissected and fixed in 4% glutaraldehyete with and without PPA [control] and processed for autoradiographic examination. Sections of 36 teeth in the same stage of development were selected and the means of net silver grain counts /Um[2] of PPA treated and control tissues of similar time interval were compared for statistical significance. Counts in PPA specimens were consistently higher for both types of cells and in all time intervals with statistical significance in differences between experimental and control mean counts. These findings suggest the formation of PPA complexes with calcium allowing its retention without interfering with its distribution either in ameloblasts or odontoblasts