| Objective:Nickel-chromium alloy ceramic prosthesis as an inexpensive production process is relatively simple, high flexural strength restorations, which is applied for a long time in China.However, biological material safety is questioned, and it gets a highly attention on the effect of periodontal tissue. Previous researches are more focus on the clinical indicators of NI-CR crown of local periodontal tissue, and the inflammatory media, enzyme changes of GCF (gingival crevicular fluid, GCF); there is not much research on periodontal pathogen which belongs to subgingival plaque and relates to periodontal disease, and most researches are only focus on static observation. The study analyses periodontal health with NI-CR porcelain crown repair teeth by observing the changes of periodontal index on nickel-chromium alloy porcelain crowns teeth before and after repaired6and12months, combined with different the time period of Pg different of positive detection rate and average relative content in Gram-negative bacteria.; On whether the time factor will increase subgingival plaque Pg infection were discussed; For the NI-CR porcelain crowns of regular maintenance to provide theoretical basis.Methods:Take30cases of patients whose first molars have been conducted nickel-chromium alloy porcelain crown repair and have healty periodontal for the study, record selected dental plaque index (PLI),Sulcus bleeding index (SBI),probing depth(PD)before restoration and6,12months after repair.16SrRNA-based polymerase chain reaction(PCR)detection method was used to determine the prevalence of pg in the subgingival plaque sample. The AVG of positive band in the agarose gel eleetrophoresis was analyzed using the automatic gel documentation and image analyzer software. The relative quantity of pg was determined. The data were statistically analyzed using SPSS18.0software.Result:1.Porcelain crowns after repair6and12months periodontal index compare the before restoration PG-positive, GBI rate difference statistically significant (P<0.05); Two groups of data for the difference of after and before PLI repair have no significant difference (P>0.05)2Periodontal index compare of6and12months after teeth NI-CR porcelain crown repair:PD, GBI, PLI, the difference was not statistically significant (P>0.05).3Before Nickel-chromium alloy porcelain crowns restored6and12months after Nickel-chromium alloy porcelain crowns restored, the average relative content of Pg in subgingival plaque Gram-negative bacteria are:9.31%,30.80%, and44.40%. Before restoration, repair,6months and12months the subgingival plaque Pg-positive rate were13.33%,43.33%,60%, two groups experienced tooth repair and restoration of teeth Pg before positive detection rate difference has statistical significance (P<0.05), to repair12months subgingival plaque Pg-positive rate is far more to repair six months increased to a certain extent, but the detection rate of difference is not significant (P>0.05). Conclusion:1Influential on periodontal index NI-CR porcelain crown repair, the positive rate of subgingival plaque in patients with Pg increased, also increased the relative content of Gram-negative bacteria, Ni-Cr alloy porcelain crown may be one of the risk factors for periodontal tissue lesions after secondary teeth.2Teeth NI-CR porcelain crown restoration for12months the periodontal index, Pg in gingival plaque in the positive detection rate and content of gram-negative bacteria compared with the six months difference had no statistical significance. suggest NI-CR PFM crown restoration with the extension of time may not add a secondary periodontal tissue lesions and plaque pg gum infection, more further research is needed for this topic. |
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