RESUMO
Objective@#To study the clinical effect of a polyetheretherketone (PEEK) bonding bridge on the loss of 3 internal incisors in patients with periodontitis.@*Methods@#This study was reviewed and approved by the ethics committee, and informed consent was obtained from the patients. Thirty-eight patients with periodontitis and 3 missing central or lateral teeth were selected to undergo restoration with a PEEK bonding bridge and then returned to the hospital 3, 6, 12, and 24 months after the restoration was completed. The survival rate of the restorations was assessed by the modified USPHS/Ryge criteria. The plaque index, gingival index, periodontal probing depth and attachment loss of the abutments were recorded, and the changes in periodontal tissues after restoration were observed and compared.@*Results@#Over 24 months of clinical follow-up observation of 38 patients, only 1 patient underwent secondary bonding after partial debonding (evaluated as grade B), while bonding was successful in the other 37 cases (evaluated as grade A). The plaque index, gingival index and periodontal probing depth were significantly lower after restoration than before (P<0.05). There was no significant change in attachment loss between before and after restoration (P>0.05).@*Conclusion@#For periodontitis patients missing 3 internal incisors, short-term PEEK bonding bridge repair has good clinical efficacy.
RESUMO
This study evaluated the effects of sodium hypochlorite (NaOC1) with different concentrations and exposure time on the structural,compositional and mechanical properties of human dentin in vitro.Sixty dentin slabs were obtained from freshly extracted premolars,randomly distributed into four groups (n=15),and treated with 1％,5％,10％ NaOC1 and distilled water (control group),respectively,for a total of 60 min.Attenuated total reflection infrared (ATR-IR) spectroscopy,Raman spectroscopy and X-ray diffraction (XRD) were carried out before,10 min and 60 min after the treatment.Scanning electron microscopy (SEM) and flexural strength test were conducted as well.The results showed that dentins experienced morphological alterations in the NaOC1 groups,but not in the control group.Two-way repeated-measures analysis of variance revealed that the carbonate:mineral ratio (C:M),Raman relative intensity (RRI),a-axis,c-axis length and full width at half maximum (FWHM) with the increase of time and concentration in the NaOC1 groups were not significantly different from those in the control group (P＞0.05).Nevertheless,the mineral:matrix ratio (M:M) increased and the flexural strength declined with the increase of concentration and the extension of time in the NaOC1 groups (P＜0.05).Additionally,it was found that the M:M and the flexural strength remained unchanged after 1％ NaOCl treatment (P＞0.05),and the morphology changes were unnoticeable within 10 min in 1％ NaOC1 group.These results indicated that NaOC1 has no significant effects on the inorganic mineral of human dentin;but it undermines and eliminates the organic content concentration-and time-dependently,which in turn influences the flexural strength and toughness of dentins.In addition,an irrigation of 1％NaOCl within 10 min can minimize the effects of NaOC1 on the structural and mechanical properties of dentin during root canal treatment.