فهرست مطالب فرناز مشرف جوادی

Dental composite resins، as the name implies، are composite materials composed of organic and inorganic elements. The main components of dental composites are polymers، organic and inorganic filers، an initiator and an activator. In addition، some elements، referred to as silanes، are added to the surface of non-organic phases or fillers of composite resins for a stable bond between the two organic and inorganic phases. The aim of this study was to review the chemical structure of dental composites with a special emphasis on nano-composites and new composites. Review Report: This review was carried out by running a search in various databases including Pubmed and ISI Web of Science from 1987 to 2010 using the key words dental composites، nano-composite and chemical structure. In the recent decade، major changes have taken place in the chemical structure of dental composites; these changes include fluoride- and calcium phosphate-releasing nano-composites and use of nano-molecular processes to construct tooth enamel by using nano-rods، nano-spheres and amelogenin. With a proper knowledge of changes in the chemical structure of dental composites، clinical behavior of these materials can be evaluated more properly. It appears that new changes are going to have important effects on the clinical behavior of newly introduced composites; however، further research is required in this respect.

Oral health-related quality of life evaluates the effect of orodental conditions on quality of daily life. The aim of this study was to evaluate relationship between quality of life and oral health in 18‒45 year-old men and women referring to Khorasgan School of Dentistry in 2010-2011.

In this descriptive-analytical study 270 subjects, 18-45 years of age, referring to Khorasgan School of Dentistry were randomly selected with equal numbers of males and females. All the subjects were examined clinically to determine DMFT (decayed, missing and filled teeth). Then the subjects completed OHIP (Oral Health Impact Profile), OIDP (Oral Impact on Daily Performance) and OHB (Oral Hygiene Behavior) questionnaires. Data was analyzed with Pearson’s correlation coefficient and t-test using SPSS 18 (α = 0.05).

The means of OHIP scores were 33.3 and 34.0 in males and females, respectively, with no statistically significant differences (p value = 0.65). OHIP scores in relation to performance management were significantly higher in males compared to females (p value = 0.03). The mean OHIP score in relation to emotional/mental dissatisfaction was significantly higher in females compared to males. There was a direct and significant relationship between all the parameters of OHIP questionnaire (p value = 0.04). OIDP scores were significantly higher in females compared to males (p value = 0.03). OHB scores did not exhibit significant differences between males and females (p value = 0.32).

The results of the present study showed that as the OHB scores increase and DMFT scores decrease, OHIB scores will decrease and the individual will have a better oral health-related quality of life; therefore, everyday life will be less affected by orodental problems.

Fluorosis is defined as a special form of injury to tooth structures, which is caused by excessive intake of fluoride during tooth development. The last fifty years have witnessed an increase in the incidence of fluorosis, necessitating special attention to the esthetic issues, diagnosis and treatment of these defects. The aim of this study was to investigate the causes, indicators, diagnosis and treatment of dental fluorosis.Review report: In this review article, the related articles were evaluated by running a Pubmed search from 1985 up to the present. After classification of the papers the most important relevant papers were selected and evaluated with an emphasis on practical therapeutic procedures. Fluorosis appears when the fluoride content of drinking water is more than 1 ppm. Severity of fluorosis depends on the duration of exposure to fluoride. The host specific body response, weight, the extent of physical activity, nutritional factors, and bone growth and development result in different severities in individuals who have been exposed to the same fluoride level. Fluorosis is classified as very mild, mild, moderate and severe. There are three special indicators for dental fluorosis: Thylstrup and Fejerskov, Dean, and TSIF. Depending on the severity of fluorosis, different treatment modalities are recommended, including bleaching, microabrasion, macroabrasion, veneers and crowns. There are different classifications for fluorosis. In addition, there are specific indicators for fluorosis, each with some advantages and disadvantages. Treatment of fluorosis is different depending on the severity of the problem and treatment outcomes are usually satisfactory.

The proliferative capacity of dental pulp cells after replantation in the alveolus facilitates pulp regeneration and subsequent root maturation. The aim of this study was to compare milk, egg white and HBSS (Hanks Balanced Salt Solution) to maintain pulp cell's proliferative capacity in open apex teeth in rabbits. Sixty open apex incisors of rabbits were randomly stored for one, three and six hours in tubes containing milk, egg white and HBSS at 4°C, immediately after open surgical extraction. Following fixation and decalcification of the teeth, three histologic sections were prepared from the coronal, middle and apical thirds of the pulp and the presence of Ki-67 antigens was evaluated in the sections by immunohistochemical methods. The mean values of liability index were analyzed using repeated measures ANOVA (α=0.05). Liability index of dental pulp cells stored in milk at one-hour, three-hour, and six-hour intervals were 13.7±4.37, 14.56±4.11, and 15.52±6.56; these indexes in egg white were 14.90±2.87, 17.66±5.9, and 12.23±3.87 and for HBSS they were 14.60±1.57, 14.14±5.02, and 18.85±6.54, respectively, during the same intervals. Pulp cells stored in milk, egg white and HBSS exhibited the same proliferative capacity at one-hour, three-hour, and six-hour intervals, with higher proliferative capacity in the apical third compared to the middle and in the middle third compared to the coronal third.

Statement of Problem: Bonding agent composition for impregnation of fiber may increase the flexural strength of fiber-reinforced composites by means of increasing adhesion. Investigating the impact of filler of four commercial bonding agents with different hydrophobicity on the flexural strength of a fiber-reinforced composite. In this experimental study, six groups (N=15 per group) of polyethylene fiber-reinforced composite specimens were prepared. In group 1, the positive control group, the samples were prepared using composite and without fiber, whereas in group 2, as the negative group, fiber-reinforced composite without any bonding agent resination was used. The fibers in group 3 to 6 were resinated with Single bond 2, Single bond, Resist, and all bond 3, respectively. Firstly, the fiber was placed in the base of the specimen preparation mold. Then the mold was filled with composite and cured. The specimens were stored in distilled water for 24 hours. In the next step, the flexural strength was measured in Three-point bending test with Instron machine at cross- head speed of 1 mm/min. Failure mode of the specimens was observed with stereomicroscope. At last, statistical analysis was performed using ANOVA and LSD post hoc tests (p < 0.05). Ono-way ANOVA test was used for evaluating the relationship among the groups, and for pair-wise comparison, LSD post-hoc test was used. One-way ANOVA test showed a significant difference among the groups. The All bond 3 group showed a significantly higher flexural strength than the other groups (p <0.001). Groups 3 to 6 had significantly higher flexural strength than flexural strength of the control groups (p <0.05). The choice of bonding agent can have a significant impact on the flexural properties of the fiber-reinforced composite. When filled hydrophobic bonding agent was used for impregnation of the fiber, compared to negative control group, flexural strength increased 4 fold.

Microleakage is one of the most important complications of direct tooth-colored restorations. One of the described methods to reduce microleakage is the use of bonding agents after finishing restorations.The purpose of this study was to evaluate microleakage associated with class V composite restorations while using rebonding on restorative margins.Method and materials: A total of 48 extracted caries-free human premolars were selected. Class five cavities were prepared on the buccal surfaces of all samples. Occlusal margins were placed in enamel while gingival margins were placed in dentin.Teeth were randomly divided into four groups of 12. Group 1 was considered as the control group, which was restored without rebonding. In groups 2, 3 and 4, after finishing and polishing, rebonding was performed by Prompt L-Pop, permaseal and Clearfil SE Bond on the restoration margins respectively. Specimens were thermocycled for 500 cycles, sealed with two layers of fingernail polish except for the occlusal and gingival margins, and immersed in fuschine 2% for 24 hours. Specimens were longitudinally sectioned with diamond disk and studied under stereomicroscope. The data were analyzed with Kruskal-Wallis and wilcoxon tests. (α = 0.05). Kruskal-wallis test showed no statistically significant differences for microleakage on occlusal (P value = 0.075) and gingival margins (P value = 0.281) among the groups. Wilcoxon test showed significant differences between occlusal and gingival margins in Prompt L-Pop (P value = 0.023) and permaseal (P value = 0.026) groups, but between the other groups, this difference was not significant. (P < 0.05). The three bonding agents applied in this study do not seem useful in decreasing microleakage into enamel and dentin margins.