The influence of the tooth preparation finish line position on the expression of matrix metalloproteinase-9 and the presence of periodontopathogens in the gingival crevicular fluid

OBJECTIVE

The objective of the study was to determine the concentration of matrix metalloproteinase 9 (MMP-9) and changes in the presence of periodontopathogens in the gingival crevicular fluid before and after tooth preparation with the subgingival and equigingival finish line position.

PATIENTS AND METHODS

The clinical prospective study included 20 subjects with an indication for upper canine preparation, with the subgingival (group 1) and equigingival finish line (group 2). Samples were taken in four observation intervals: 5 minutes before (control samples), as well as 15 minutes, 24 and 72 hours after tooth preparation (experimental samples). Measurement of MMP-9 was done using Enzyme-linked Immunosorbent Assay (ELISA). The presence of bacteria in the gingival fluid was proven by the Polymerase chain reaction (PCR) analysis.

RESULTS

The MMP-9 values did not differ statistically significantly between the groups (p=0.524). The MMP-9 values showed a statistically significant difference in the given observation period (p<0.001) with a significant linear increase in values (p<0.001). A significant quadratic trend recorded a decrease in the MMP-9 values 15 minutes after preparation, and an increase 24 hours after preparation, without a significant difference in the interaction between groups (p=0.392). After preparation, a significant difference in the presence of periodontopathogens was confirmed, i.e., a decrease in the presence of Prevotella intermedia (p=0.025) and Tannerella forsythia (p=0.016) in group 1, and an increase in the presence of Aggregatibacter actinomycetemcomitans in both groups (p=0.029, p=0.026).

CONCLUSIONS

The study is a good basis for determining the influence of tooth preparation on gingival inflammation, with therapeutic (choice of preparation technique) and preventive significance regarding the protection of the periodontal tissue from possible iatrogenic damage.

Fibrinogen Modification and Fibrin Formation in Patients with an End-Stage Renal Disease Subjected to Peritoneal Dialysis

End-stage renal disease (ESRD) is a condition accompanied by increased inflammation, oxidative stress, risk of cardiovascular complications, and coagulopathies. The structure of fibrinogen and characteristics of fibrin from plasma samples of ESRD patients on peritoneal dialysis (PD) was investigated. Fibrinogen from ESRD patients had a higher degree of carbonylation than fibrinogen from healthy individuals. The Aα chain was the most susceptible to oxidation, followed by the Bβ chain, whereas the γ-chain was the most resistant to oxidation. Spectrofluorimetric analysis suggested a higher extent of modification of amino acid side chains in fibrinogen from ESRD patients. The tertiary structure of fibrinogen was more affected than its secondary structure. The kinetics (time and rate) of fibrinogen coagulation did not differ between the tested groups. Fibrin prepared from the isolated fibrinogen had a similar structure in both groups. Our results confirm that oxidation and structural alterations of fibrinogen occur in ESRD patients on PD, although these modifications produce no direct effect on the fibrin formation. Taking into account that some patients suffer from bleeding, whereas others develop thrombotic complications, further research on this subject is required to identify other components and processes that contribute to the outcome.

Analysis of Four Circulating Complexes of Insulin-Like Growth Factor Binding Proteins in Human Blood during Aging

The primary role of insulin-like growth factor binding proteins (IGFBPs) is to regulate availability of IGFs for interacting with receptors, but IGFBPs perform IGF-independent actions as well. The availability and activity of IGFBPs in the circulation is influenced primarily by their concentration and structural modifications, but possibly also by interaction with major plasma proteins such as transferrin, alpha-2-macroglobulin (α2M), and fibrinogen. Four types of circulating IGFBP complexes were examined in this study by immuno- and ligand-binding assays in adults of different age. The amounts of IGFBP-3/transferrin and IGFBP-1/fibrinogen complexes were similar in middle- and old-aged persons, whereas the amounts of IGFBP-1 (or -2)/α2M monomer complexes were lower in the old-aged group and negatively correlated with total IGFBP-1 (or -2) amounts in blood. In contrast to IGFBP-1, IGFBP-2 was present in significantly greater quantities in complexes with α2M dimer than α2M monomer in older individuals. IGFBP complexes did not bind ¹²⁵I-labeled IGF-I in amounts detectable by ligand blotting. According to the results of this study, the quantities of IGFBP-1 and IGFBP-2, which interact with α2M, are age-dependent and, in the case of complexes with α2M monomer, they are negatively correlated with the total circulating levels of these two IGFBPs.