IADR Abstract Archives
Phosphorylated Dihydroceramide And Serine Lipids On Extracted Human Primary Teeth
Objectives: This investigation determined whether these bacterial lipids could be recovered on primary human teeth.
Methods: Control teeth (exfoliated primary human teeth, n=25) served as controls and primary teeth extracted due to caries (n=75) were collected. Permanent teeth included a tooth with a prosthetic crown and no apparent subgingival calculus, and two additional permanent teeth with heavy subgingival calculus deposits. Total lipids were extracted from primary teeth (25 per group) and each permanent tooth using both a neutral phospholipid extraction followed by acidic extraction. Aliquots of each lipid sample (1 mg) were dissolved in methanol and analyzed using electrospray-MS/MS (LC-ESI-MS). For comparison, total lipids of P. gingivalis were extracted and fractionated using semi preparative HPLC. An aliquot of each HPLC fraction was then evaluated for the lipids of interest using LC-ESI-MS.
Results: Primary teeth were contaminated with Lipid 654 and phosphoethanolamine dihydroceramide lipids. The lipid extract from the permanent tooth with no visible subgingival calculus showed no bacterial lipids. However, the permanent teeth laden with subgingival calculus contained substantial levels of unsubstituted phosphoglycerol dihydroceramide lipids (unsub PG DHC) compared to all other lipid classes. Unsub PG DHC lipids are minor constituents recovered in HPLC fractions of P. gingivalis lipids and in lipid extracts of primary teeth.
Conclusions: These results suggest that the organisms recovered on primary teeth do not make the bacterial lipids characteristic of those recovered on periodontitis-afflicted teeth laden with calculus. Furthermore, these results suggest that sub PG DHC lipids are converted to unsub PG DHC lipids in or on subgingival calculus.
Methods: Control teeth (exfoliated primary human teeth, n=25) served as controls and primary teeth extracted due to caries (n=75) were collected. Permanent teeth included a tooth with a prosthetic crown and no apparent subgingival calculus, and two additional permanent teeth with heavy subgingival calculus deposits. Total lipids were extracted from primary teeth (25 per group) and each permanent tooth using both a neutral phospholipid extraction followed by acidic extraction. Aliquots of each lipid sample (1 mg) were dissolved in methanol and analyzed using electrospray-MS/MS (LC-ESI-MS). For comparison, total lipids of P. gingivalis were extracted and fractionated using semi preparative HPLC. An aliquot of each HPLC fraction was then evaluated for the lipids of interest using LC-ESI-MS.
Results: Primary teeth were contaminated with Lipid 654 and phosphoethanolamine dihydroceramide lipids. The lipid extract from the permanent tooth with no visible subgingival calculus showed no bacterial lipids. However, the permanent teeth laden with subgingival calculus contained substantial levels of unsubstituted phosphoglycerol dihydroceramide lipids (unsub PG DHC) compared to all other lipid classes. Unsub PG DHC lipids are minor constituents recovered in HPLC fractions of P. gingivalis lipids and in lipid extracts of primary teeth.
Conclusions: These results suggest that the organisms recovered on primary teeth do not make the bacterial lipids characteristic of those recovered on periodontitis-afflicted teeth laden with calculus. Furthermore, these results suggest that sub PG DHC lipids are converted to unsub PG DHC lipids in or on subgingival calculus.