Abstract

Adults have secondary teeth and children primary teeth. Covered by enamel, their crowns have dentin below that gives them volume. The embryological difference of these tissues creates a clearly defined amelodentinal junction [ADJ]. In secondary teeth, the enamel shows lower mineralization stages called striae of Retzius, which should also be visible in primary teeth. Our objectives were to compare the histological aspect of ADJ, its relationship with dentine structures and the striae of Retzius in both dentitions. 

Material and Methods: Seven secondary and seven primary teeth were used [n = 14]. A cutting line was drawn on the enamel, then a groove was made with a metal disc to the dentin and the piece was separated by a quick blow with a sharp-edged tool. With an abrasion technique, a translucent sheet was obtained that was adhered to the slide. Using an optical microscope at lower magnification, the ADJ was classified in complete and non-complete. At higher magnification, in the non-complete part the cause was analyzed. The number of lines was classified in one and/or several and the thickness in thin and thick. 

Statistical Analysis: Fisher's exact test and Chi-squared exact test 5%. 

Results: In secondary teeth, the junction was 100% complete, crossed by dentinal structures that did not modify their vision; in primary teeth, only 14% were complete, showing the same grouped structures covering some sections. In secondary teeth, 71% had several lines, 57% thin, 14.5% thick and 28.5% not visible; in primary teeth, 57% had only one [p = 0.296]; lines with values of 43%, 43% and 14% respectively [p = 0.4654]. 

Conclusion: In secondary teeth, the ADJ was complete and dentinal structures did not hide it, in primary teeth they were grouped partly covering the ADJ. In secondary teeth, given the greater volume of the crown, there were several short periods of lower mineralization that produced more striae of Retzius, while in primary teeth there were shorter and longer periods producing thin and thick lines that modified their histological appearance.

Keywords: Incremental Lines; Embryological Origin; Mineralization; Human Dentition Secondary; Primary Teeth

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Citation

Citation: Kohli Bordino Alicia Noemi and Cueto Santiago. "Histological Comparison of Amelodentinal Junction and Striae of Retzius in Donated Secondary and Primary Teeth”. Acta Scientific Dental Sciences 4.4 (2020): 26-31.

Copyright

Copyright: © 2020 Kohli Bordino Alicia Noemi and Cueto Santiago. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.