RESUMEN
Objective: Secondary caries is a common problem in dental treatments and its occurrence is attributed to several factors. The present study aimed at assessing the prevalence of secondary caries in posterior teeth of patients presenting to the Department of Operative Dentistry, Shahid Beheshti Dental School
Methods: This descriptive study was conducted on 350 patients with 1,339 posterior teeth restored with amalgam or composite resin. Restorations older than 3 years were evaluated. Data regarding presence or absence of secondary caries, age of restoration, location of receiving dental care, tooth brushing technique and use of dental floss and mouthwash were recorded in a questionnaire. Statistical analysis was done using chi-square test
Results: The prevalence of secondary caries was 26% among the understudy patients. Mesio Ocluso Distal restorations [19.2%] had the highest prevalence of secondary caries. Composite restorations had higher prevalence of secondary caries compared to amalgam restorations [p=0.01]. Teeth restored in private dental offices had a higher prevalence of secondary caries compared to those restored in university clinics [p=0.007]. Patients who used mouthwash had a significantly lower prevalence of caries recurrence [p=0.05]
Conclusion: The prevalence of secondary caries in patients presenting to the Department of Operative Dentistry of Shahid Beheshti Dental School was higher in the MOD restorations, composite restorations and teeth restored in private dental offices finally it was less in the patients using mouthwash
RESUMEN
In this in vitro study, the long-term bond strength of a self-adhesive resin cement and conventional resin cements to human enamel and dentin was compared. 80 sections of intact human third molars were randomly assigned into eight groups according to the cement type [Rely X Unicem [RXU], Rely X ARC [RXA]], bond substrate [enamel, dentin] and the duration of water storage [24 h or 1 year]. Rods of cements [0.75×1 mm] were prepared on the top surface of specimens using Tygon tubes. The micro-shear bond strengths of specimens were measured by a micro-tensile tester. Data were analyzed using Wilcoxon signed ranks and Mann Whitney tests [alpha =0.05]. The bond strengths of RXA and RXU cements to enamel after 24h were 18.56 +/- 4.08 MPa and 14.99 +/- 4.17 MPa, and after 1 year were 19.41 +/- 6.24 MPa and 15.51 +/- 6.17 MPa, respectively. The bond strengths of RXA and RXU cements to dentin were 13.36 +/- 4.02 MPa and 14.16 +/- 4.69 MPa after 24h, and 14.63 +/- 5.96 MPa and 14.08 +/- 6.72 MPa after 1 year, respectively. Tooth substrate had significant effect only on the shear bond strength of RXA cement after 24h [P=0.01], while no other significant differences were found in this study [P>0.05]. According to the results of this study, one-step self-adhesive and multi-step conventional resin cements were similarly effective in bonding to enamel and dentin after 1 year water storage