فهرست مطالب sara nuroloyuni

Dental caries is one of the most chronic diseases in children. Various factors were effective in incidence andprevalence of dental caries. The aim of this study was to determine the dental caries prevalence among 6-12 yearsold school children in Ardabil city. In this descriptive–cross sectional study a total of 847 school children (444 girls and 403 boys) were randomly selected from public and private schools in all over of Ardabil city.Clinical examination of children have been done for dental caries according to world health organization (WHO) criteria including determination of DMFT, dmft, DMFS and dental caries prevalence. Data were analysedin SPSS.16 by statistical methods. Total prevalence of dental caries was 79.7% in children with 71.1 % in permanent and 88.3 % in primary dentition. The mean of dmft, DMFT, DMFS indexes were 2.74± 0.09, 1.6±0.1, and 3.5± 0.1, repectively.Results showed that there was a significant relation between DMFT, dmft and DMFS and age group. Results showed that the dental caries prevalence among 6-12 years-old school children in Ardabil city was higher than the world standard. Therefore, improving the existing dental services, programing and performing education, prevention and treatment programs for oral health between school children seems tobe necessary in the future.

In contrast to prepared natural dentin abutments, little is known concerning factors influencing the retention of fixed prostheses cemented to implant abutments. The aim of this study was to investigate the effect of implant abutment height on the retention of single castings cemented to wide and narrow platform implant abutments. Thirty-six parallel-sided abutments (Biohorizon Straight Abutment) of narrow platform (NP) and wide platform (WP) sizes with their analogs were used. In each group of platform size, abutments were prepared with axial wall heights of 5, 4, 3, 2 mm (n=9). On the whole 72 castings were constructed, which incorporated an attachment to allow removal. Castings were cemented to abutments with TempBond®. A uniaxial tensile force was applied to the crown using an Instron machine until cement failure occurred. Analysis of variance of the models were fit to determine the effect of height of abutment of the restorations on the mean tensile strength (α=0.05). The mean peak removal force for corresponding abutments was significantly different (P < 0.05): (1) with platform sizes: WP > NP; (2) with alteration of axial wall height for NP: 5 mm > 4 mm > 3 mm = 2 mm and for WP: 5 mm > 4 mm = 3 mm = 2 mm. The retention of NP cement-retained restorations is influenced by the wall height but not in same manner as WP. Restorations of narrow-platform size with longer abutment exhibited higher tensile resistance to dislodgement.