Acid Resistance of the Enamel in Primary Second Molars from Children with Down Syndrome and Cerebral Palsy

David Keinan1, Anna Radko2, Patricia Smith1, Uri Zilberman1, *
1 Laboratory of Bioanthropology and Ancient DNA, Hadassah School of Dental Medicine, Hebrew University, POB 12272, Jerusalem, 91120, Israel
2 The Unit for Nanoscopic Characterization, The Hebrew University of Jerusalem, E. Safra Campus Givat Ram, Jerusalem, 91904, Israel

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© Keinan et al.; Licensee Bentham Open.

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* Address correspondence to this author at the Laboratory of Bioanthropology and Ancient DNA, Hadassah School of Dental Medicine, Hebrew University, POB 12272, Jerusalem, 91120, Israel; Tel: +972 -2-6758577; Fax: +972-2- 6757451; E-mail:



This study was carried out to evaluate the extent of differences in mineralization of inner and outer enamel of the lower primary second molars of children with Down syndrome (DS) and Cerebral Palsy (CP) as revealed by acid treatment of exfoliated teeth. The results were compared to those obtained from a control group of healthy children.


The sample included 4 mandibular second molars from each group. On each tooth, a thin section was cut, bisecting the mesial cusps. The analysis was carried out on the mesio-buccal cusps. Atomic force microscopy (AMF) was used to analyze the morphological structure of the dental enamel after 10 sec of 0.1 mol% citric acid treatment. The measurements were performed on 3 points in the enamel close to the outer surface and 3 points in the enamel close to the dentin. The differences between groups were analyzed using Mann Whitney tests.


In controls and CP teeth the outer enamel was more resistant to etching than the inner enamel. In DS teeth both outer and inner enamel showed similar results for all parameters. Between group comparisons showed that roughness values were significantly higher (P<0.01) in DS teeth than in either controls or CP teeth. No significant differences were found between CP and control teeth.


The higher values obtained for DS enamel reflect increased solubility of the enamel to acid relative to controls and CP teeth together with irregularity of the organic matrix. The practical importance of the results is that DS primary molars needs reduced etching time when prepared for pit and fissure sealants or composite/compomer restorations.

Key Words: Down syndrome, cerebral palsy, enamel, acid treatment, AFM.