Effect Of Porcelain-fused-to-metal Crowns With Different Metal Base Alloys On The Level Of MMP-8in Gingival Crevicular Fluid Of The Abutment

Objective: To compare and evaluate the restorative effect of thedifferentkinds of PFM restorations from the aspect of the clinical indicators andthe experiment indexes by testing metalloproteinases-8(MMP-8) levelin therelevant gingival crevicular fluid (GCF) at the point of six monthsafter crownrestorations of diverse PFM crowns in order to offer the experiment evidencefor estimating the effect of clinical prost-hesis and selecting the substratematerials of PFM reasonably.Methods: Fifty anterior teeth intending to carry out PFM crownrestorations were selected for experiment. According to the sequence of seeingdoctor and different PFM crow restoration,the patients by random weredivided in five groups, i.e. Ni-Cr PFM crown group, Ti alloy PFM crowngroup,Co-Cr PFM crown group, Ag-Pd PFM crown group and Au-Pt PFMcrown group, of which per group were ten teeth. Under the circumstances ofstrictly limiting periodontal conditions, shoulder preparation,margin adaptationand crown axial contour and so on. The samples of GCF of four labial andlingual mesial interaxial angle and distal interaxial angle were collected byfilter paper sucking method prior to preparing the tooth and six month aftercementati on by filter paper strips of2×10mm.The concentration of MMP-8inthe gingival crevicular fluid (GCF) was tested by enzyme-linked-immunosorbent assay(ELISA) method, and analyzed the variational relation ofthe volume of GCF and MMP-8between the pre-restoration and post-restoration compared with pre-restoration as the standard.Results: According to Ni-Cr alloy, Ti alloy and Co-Cr alloy PFM crowngroup, the indexes of clinic and GCF showed a statistic difference (P<0.05)between pre-restoration and six months after restoration. According to Ag-Pd PFM crown group and Au-Pt PFM crown group, the indexof clinic and GCFhad no statistic difference (P>0.05) between pre-restoration and six monthsafter restoration. All kinds of indexes had no statistic difference (P>0.05)between Ni-Cr PFM crown group and Ti alloy PFM crown group after sixmonths after restoration. However, all kinds of indexes showed a statisticdifference (P<0.05) compared Ni-Cr PFM crown group with Co-Cr PFM crowngroup, Ag-Pd PFM crown group andAu-Pt PFM crown group after six monthsafter restoration. All kinds of indexes showed a statistic difference (P<0.05)compared Ti alloy PFM crown group with Co-Cr alloy, Ag-Pd alloy and Au-Ptalloy PFM crown group after six months after restoration. All kinds of indexesalso showed a statistic difference (P<0.05) compared Co-Cr PFM crown groupwith Ag-Pd PFM crown group and Au-Pt PFM crown group after six monthsafter crown cementation. All indexes have no significant difference (P>0.05)between Ag-Pd PFM crown group and Au-Pt PFM crown group.Conclusions: According to Ni-Cr alloy, Ti alloy and Co-Cr alloy PFMcrown group, the metal materials of PFM crowns are susceptible to stimulationof the periodontal tissue and inflammatory symptom six months afterrestoration. However, there is no significant stimulation in Ag-Pd PFM crowngroup and Au-Pt PFM crown group. Thereinto, comparing the stimulation ofthe periodontal tissue show that Ag-Pd PFM crown group and Au-Pt PFMcrown group are the lowest (there is no significant difference between Ag-PdPFM crown group and Au-Pt PFM crown group), Co-Cr alloy group takesecond place, and Ni-Cr alloy group and Ti alloy PFM crown group are thehighest(there is no significant difference between Ni-Cr alloy and Ti alloy PFMcrown group). The excretive volume of GI、GCD、GCF and the density ofMMP-8act as indexes of evaluating gingival inflammation in the experiment,which is used for reference to monitor the effect of clinical applications of thedifferent kinds ofPFM.