Salivary a-amylase protects enamel surface against acid induced softening

TY - ABST

T1 - Salivary a-amylase protects enamel surface against acid induced softening

AU - Lazovic, Maja Bruvo

AU - Moe, Dennis

AU - Kirkeby, Svend

AU - Vorum, Henrik

AU - Jensen, Allan Bardow

PY - 2011/3/18

Y1 - 2011/3/18

N2 - Objectives: Recently we have demonstrated individual differences in protection against acid-induced enamel softening offered by experimentally developed saliva pellicles. Although ethnicity seemed to be related to protection level, the saliva proteins responsible for the differences were not identified. Accordingly, the aim of this study was to identify the proteins responsible. Methods: Sour taste stimulated parotid saliva was collected from 20 subjects (23±1 years) comprising ten Scandinavians (Sc) and ten non-Scandinavians (NSc) including two Arabs, two Persians, four Pakistanis, one Indian, and one Chinese. After collection, saliva was dialysed and lyophilised and re-dissolved at 0.5% in Type I water. Next, four polished bovine enamel specimens were immersed into each sample under gentle and constant shaking for 12 hours. Last, specimens were exposed to an erosive challenge of pH 2.3 for 4 min along with measurements of surface microhardness (SMH). Changes in SMH from before to after exposure were used to calculate the protective effect of each saliva sample. Quantification and identification of salivary proteins was performed by dual wavelength HPLC at various conditions and MALDI-TOF mass fingerprinting following trypsin digestion. Each persistent peak in the HPLC chromatograms was related to the protective effect against acid-induced enamel softening obtained by the corresponding saliva sample by multiple regression analysis. Results: One peak identified as a-amylase had an explanatory power of 39% in the analysis with high concentrations being most protective (p<0.001). In addition, a smaller peak retrieved later in the chromatograms also had a strong protective effect. Inclusion of this peak in the analysis increased the explanatory power of amylase on protective effect to 65% (p<0.001). However, due to shortness of sample the second peak was not identified. Conclusion: Protective effects of experimentally developed salivary pellicles can be related to their protein composition, although, not all proteins could be identified in this study.

AB - Objectives: Recently we have demonstrated individual differences in protection against acid-induced enamel softening offered by experimentally developed saliva pellicles. Although ethnicity seemed to be related to protection level, the saliva proteins responsible for the differences were not identified. Accordingly, the aim of this study was to identify the proteins responsible. Methods: Sour taste stimulated parotid saliva was collected from 20 subjects (23±1 years) comprising ten Scandinavians (Sc) and ten non-Scandinavians (NSc) including two Arabs, two Persians, four Pakistanis, one Indian, and one Chinese. After collection, saliva was dialysed and lyophilised and re-dissolved at 0.5% in Type I water. Next, four polished bovine enamel specimens were immersed into each sample under gentle and constant shaking for 12 hours. Last, specimens were exposed to an erosive challenge of pH 2.3 for 4 min along with measurements of surface microhardness (SMH). Changes in SMH from before to after exposure were used to calculate the protective effect of each saliva sample. Quantification and identification of salivary proteins was performed by dual wavelength HPLC at various conditions and MALDI-TOF mass fingerprinting following trypsin digestion. Each persistent peak in the HPLC chromatograms was related to the protective effect against acid-induced enamel softening obtained by the corresponding saliva sample by multiple regression analysis. Results: One peak identified as a-amylase had an explanatory power of 39% in the analysis with high concentrations being most protective (p<0.001). In addition, a smaller peak retrieved later in the chromatograms also had a strong protective effect. Inclusion of this peak in the analysis increased the explanatory power of amylase on protective effect to 65% (p<0.001). However, due to shortness of sample the second peak was not identified. Conclusion: Protective effects of experimentally developed salivary pellicles can be related to their protein composition, although, not all proteins could be identified in this study.

M3 - Conference abstract for conference

T2 - IADR General Session &amp; Exhibition

Y2 - 16 March 2011 through 19 March 2011

ER -