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The amelocemental junction in young premolar teeth. A replica study by scanning electron microscopy
J Bevenius1, S Lindskog, K Hultenby
1Department of Cariology, Karolinska Institutet, Stockholm, Sweden.
Acta Odontologica Scandinavica
|June 1, 1993
Summary
This study re-evaluated the amelocemental junction in premolars. An edge-to-edge enamel-cementum relationship was most common, challenging previous findings on cementum overlap.
Area of Science:
- Dentistry
- Oral Biology
- Microscopy
Background:
- The amelocemental junction (ACJ) is crucial for tooth structure and integrity.
- Traditional data on the frequency of enamel-cementum relationships at the ACJ require validation.
- Artefacts from specimen preparation can lead to misinterpretations of ACJ morphology.
Purpose of the Study:
- To investigate the accuracy of existing data on ACJ relationships.
- To document the precise relationship between root cementum and coronal enamel at the ACJ.
- To identify and mitigate preparation artefacts in ACJ analysis.
Main Methods:
- Examined 50 young premolars using replica techniques for scanning electron microscopy (SEM).
- Utilized polarization microscopy on thin ground sections (< 40 microns).
- Classified 170 prepared surfaces based on enamel-cementum relationships at the ACJ.
Main Results:
- An edge-to-edge relationship between enamel and cementum was observed in 76% of surfaces.
- Cementum overlap onto cervical enamel occurred in 14% of surfaces.
- Apparent 'gaps' were reclassified as cementum ditches, with no exposed dentin observed.
Conclusions:
- The edge-to-edge relationship is the predominant pattern at the ACJ in this sample.
- Cementum overlap is less prevalent than previously reported.
- The applied methods minimized preparation artefacts, providing a more accurate representation of the ACJ.