Dental caries experience and socio-economic status among Iranian children: a multilevel analysis.

BACKGROUND: Socio-economic factors are considered as main determinants causing disparities in oral health across different countries. The aim of the present study was to investigate the associations of social and economic factors with dental caries experience among 6- and 12-year-old Iranian children. METHODS: In this cross-sectional study, a total of 31,146 students, aged 6 and 12 years old, were enrolled from all (31) provinces in Iran. Based on the standardized World Health Organization (WHO) criteria for oral health surveys, dental caries indices in primary and permanent teeth were assessed by clinical examination in schools. Data on socio-economic status was obtained from the modified WHO questionnaire and national data bank. The decayed, missing and filled teeth (dmft/DMFT) indices for primary and permanent dentition were compared at the individual and provincial levels using multilevel regression analysis. Poisson regression analysis was used to evaluate the association of social (demographic and behavioral) determinants with dental caries indices among individuals. To assess the causes of difference in dental caries indices across provinces, justifiable economic factors were also analyzed using poisson regression analysis. RESULTS: The mean (SE) of dmft and DMFT were 5.84 (0.05) and 1.84 (0.03), for 6-and 12-year-old children, respectively. The differences of dental caries indices were statistically significant among provinces. Higher level of parental education was negatively related to dental caries indices of both age groups. Rural residency was positively and dental flossing was reversely associated with dmft index of 6-year-old children. Negative associations were found between frequency of tooth brushing and preventive dental utilization with dmft and DMFT indices. Gross Domestic Product (GDP) index had negative and Consumer Price Index (CPI) had positive associations with dmft and DMFT indices in both age groups. However, positive relationships were observed between Gini index with DMFT index among 12-year-old children; as well as between the number of dentists per capita with dmft index among 6-year-old children. CONCLUSION: Socio-demographic and behavioral factors were found to be associated with dental caries experience. However, economic indicators had the greatest importance.

Effects of fresh mineralized dentin and cementum on socket healing: a preliminary study in dogs.

OBJECTIVES: Dentin is composed of many minerals and growth factors. Based on this composition, we studied its effect as a possible regenerative material for alveolar healing. MATERIALS AND METHODS: This study was conducted using four 2.5-year-old mongrel dogs (male; weight, 25 to 30 kg). The third mandibular premolars were carefully mobilized with a dental elevator and then removed using forceps. The crown portions of the extracted teeth were removed with cutters, and the root portions of the remaining teeth were collectively trimmed as closely as possible to 350 to 500 µm. Dentin and cementum (DC) chips harvested from the extracted teeth were soaked in blood and packed into the fresh sockets (autograft). Biopsies were performed at the ends of day 14 and day 56 following implantation. Data were expressed as mean±standard deviation and compared with t-test results. RESULTS: The ratio of SA(bone) to total area of each probe was determined and was 170±16 µm(2) for the control group and 71±14 µm(2) for the DC group, a significant difference (P<0.05). CONCLUSION: DC particulate grafts offered no improvement in bone regeneration in alveolar extraction sockets.

Distraction osteogenesis for cleft palate closure: A finite element analysis.

BACKGROUND: Current methods of closure of the cleft palate result in the formation of scars and impairment of growth. Distraction osteogenesis (DO) might be an effective means to repair or at least reduce the size of wide clefts. This study investigates the biomechanical aspects of this process. MATERIALS AND METHODS: DO simulation was applied to reduce the size of a unilateral hard palate cleft on a three-dimensional (3D) model of the maxilla. For the position of osteotomy lines, two different models were assumed, with the osteotomy line on the affected side in model A and on the intact side in model B. In each model, DO screws were placed on two different positions, anteriorly (models A1 and B1) and posteriorly (models A2 and B2). Displacement pattern of the bony island in each of the four models, reaction forces at DO locations, and von Mises stress were estimated. Mesh generation and data processing were carried out in the 3D finite element analysis package (ABAQUS V6.7-1; Simulia Corp., Providence, RI, USA). RESULTS: In model B2, the island moved almost evenly, assuring a more complete closure of the cleft. The most uniform stress distribution was found in model B1. CONCLUSION: The results suggest that the best positions for the DO screw and the osteotomy line for closure of the cleft palate are posteriorly and on the intact side, respectively.