ABSTRACT
Toll-like receptor 2 (TLR2) activation has been implicated in the pathogenesis of periodontal disease but the identity of the TLR2 agonists has been an evolving story. The serine/glycine lipids produced by Porphyromonas gingivalis are reported to engage human TLR2 and will promote the production of potent pro-inflammatory cytokines. This investigation compared the recovery of serine/glycine lipids in periodontal organisms, teeth, subgingival calculus, subgingival plaque, and gingival tissues, either from healthy sites or periodontally diseased sites. Lipids were extracted using the phospholipid extraction procedure of Bligh and Dyer and were analyzed using liquid chromatography/mass spectrometry for all serine/glycine lipid classes identified to date in P. gingivalis. Two serine/glycine lipid classes, Lipid 567 and Lipid 1256, were the dominant serine/glycine lipids recovered from oral Bacteroidetes bacteria and from subgingival calculus samples or diseased teeth. Lipid 1256 was the most abundant serine/glycine lipid class in lipid extracts from P. gingivalis, Tannerella forsythia, and Prevotella intermedia whereas Lipid 567 was the most abundant serine/glycine lipid class recovered in Capnocytophaga species and Porphyromonas endodontalis. Serine/glycine lipids were not detected in lipid extracts from Treponema denticola, Aggregatibacter actinomycetemcomitans, or Fusobacterium nucleatum. Lipid 1256 was detected more frequently and at a significantly higher mean level in periodontitis tissue samples compared with healthy/gingivitis tissue samples. By contrast, Lipid 567 levels were essentially identical. This report shows that members of the Bacteroidetes phylum common to periodontal disease sites produce Lipid 567 and Lipid 1256, and these lipids are prevalent in lipid extracts from subgingival calculus and from periodontally diseased teeth and diseased gingival tissues.
ABSTRACT
PURPOSE: To systematically review the current scientific evidence to assess if healing abutments and cover screws for dental implants can be resterilized effectively for reuse. A secondary purpose was to investigate if there has been any reported adverse biological or mechanical consequences to implants, or harm to patients with the reuse of healing abutments or cover screws. MATERIALS AND METHODS: An electronic search of the English language scientific literature was performed independently by multiple investigators using a systematic search process using the PubMed search engine and Cochrane database. After the application of predetermined inclusion and exclusion criteria, the final list of articles was reviewed to meet the various objectives of this review. RESULTS: The initial electronic search resulted in 657 titles and after the application of predetermined inclusion and exclusion criteria, six articles were identified that satisfied the study objectives. All six articles were observational studies that described a total sample of over 300 used healed abutments obtained from patients. Out of these, three studies showed that routine methods (mechanical, chemical, and steam) used for cleaning and sterilizing used healing abutments did not result in the complete removal of contaminants, while two studies showed that routine methods supplemented with an additional regimen resulted in adequate decontamination. One additional study showed that routine methods sufficiently resulted in adequate decontamination of used healing abutments. There were no true clinical studies identified. There were no studies identified in the literature that reported on any adverse consequences to dental implants, such as infections, bone loss, mechanical complications, implant failure, or harm to patients, by reuse of healing abutments or cover screws. CONCLUSIONS: Limited evidence suggests that routine methods used for cleaning and sterilization of used titanium healing abutments may not result in the complete removal of contaminants. However, the biological or mechanical implication of this finding is yet to be determined because presently there are no reports in the literature related to any unfavorable consequences to dental implants, or harm to patients by reuse of healing abutments or cover screws. Nevertheless, due to the popular clinical practice of reusing healing abutments to reduce cost to clinicians and patients, indiscriminate reuse of healing abutments should be avoided, until further supporting evidence is established.