[Relationship between birth weight and eruption time of first deciduous tooth]

Tooth eruption is complex process that involves different mechanisms. Low birth weight [LBW] infants are prone to many serious medical problems during the neonatal period which may affect the development of oral tissues. The aim of this study was to evaluate the relationship between the birth weight and eruption time of the first primary tooth. We have conducted a cohort study on70 full term infants [35 low BW, 35 Normal BW]. This study was conducted in Al-Zahra hospital of Rasht-Iran in 2007.The infants observed periodically since 3rd month of birth until the first tooth eruption. X2 test has been used for comparison of the two groups and since month 8th the regression logistic test to determine the effect of relative birth weights risks and other variables in tooth eruption. The first erupted tooth was mandibular central incisor with [8.26 +/- 2.72] month in case group and [7.76 +/- 3.18] month in control group and there was no statistical difference between two groups, The first deciduous tooth had erupted in 51.4% of LBW and 42.9% of NBW infants until 8 months Relative risk of delay eruption after 8 months in LBW infants was 1.2.[RR=1.2]. Birth weight in full term infant wasn't influence on the first deciduous tooth eruption time

[Prevalence and etiology of anterior permanent teeth crown fracture in elementary students in Rasht in 2007]

Regarding to the importance of anterior permanent teeth in mastication, speaking and esthetic, also high prevalence of crown fracture due to traumatic injuries of the permanent teeth, this study was designed to evaluate the etiology and prevalence of crown fracture of anterior permanent teeth in 2nd-5th grade children of primary schools in Rasht, in year 2007.For this descriptive, cross-sectional study 1042, 2nd-5thgrade students were selected from 10 randomly chosen primary schools in Rasht. Examination was carried out by flash light. Information in regard to age, gender, type of crown fracture, tooth number, amount of over jet, overbite, lip seal, etiology of trauma and performed treatments following trauma were recorded. The data were analyzed with SPSS software and Chi-Square test. Prevalence of crown fracture in anterior teeth was 15.2%. The male to female ratio was 1.7/1.Maxillary central incisors were the most affected [53.5%] and the most common type of crown injury was enamel fracture [80.3%]. Most of injuries had occurred at home [49%] and during summer [40.8%]. Falls and foreign bodies striking were the most frequent cause of dental traumatic injuries. There was a tendency for children with an increased over jet and deep bite to have more dental injuries

[Prevalence of enamel defects and associating factors in permanent incisors and first molars in 8-9 years-old children]

Enamel developmental defects may be classified as heritable or environmentally induced defects. Incisors and molars are usually involved. The affected molars create problems for the patients due to hyper-sensibility and caries susceptibility and often require extensive treatment. Many studies were performed to determine the prevalence of enamel defects and conflicted results have been obtained. Determine the prevalence of enamel defects and associating factors in permanent incisors and first molars in 8-9 year-old children of Rasht 2007. This was a descriptive and cross-sectional study. The sample consisted of 538 students aged in 8-9 year-old who were randomly selected from 16 schools in Rasht. The Developmental Defects of Enamel [DDE] index was used to assess permanent incisors and first molars, which were dried prior to examination and a light was used for evaluation. A questionnaire about possible etiological factors of enamel defects were sent to parents of children. Data were analyzed with SPSS software by chi-square test. Multivariate analyses were performed using logistic regression analysis. 126[23.4%] of children had enamel defects in at least one tooth. 12.8% had at least one affected molar. White/Cream opacity was the most common type of enamel defect. Maxillary central incisors were the most commonly affected tooth. Mother's diseases during the last trimester, urinary tract infections, diarrhea and vomiting and high-fever diseases during the first 5 yrs of life showed a high association with enamel defects. It is necessary to inform parents about the prevalence and etiology of the enamel defects by gynecologists, pediatricians and dentists

[Survey the relationship between the type of delivery and enamel defects of the first permanent molars]

The enamel of the permanent first molars is initiated at about the 20[th] weeks in uterine. The first partially mineralized enamel matrix is laid down, starting at the sites of future cusps. At birth, the secondary mineralization has started at the cusps and the mineralization continues during the first years after birth. The researches indicated that any stressful event during birth [like cesarean section delivery] is likely to result in clinically evident enamel defects. A few researches considered the possible relation between type of delivery and enamel defects. To investigate the relationship between type of delivery and enamel defects of the first permanent molar. In this analytical historical cohort study, 120 children who were 7-8years-old and had born by cesarean delivery and 120 children at the same age who had born by normal vaginal delivery were chosen to examine clinical feature of their first permanent molars. In cesarean group, there were 60 children who had born by urgent cesarean and 60 children by elective cesarean. The birth files of 1999- 2000 years were extracted and the information about type of delivery, mothers age, and infants health at birth was collected. Enamel defect was recorded according to DDE index. Data was analyzed by T-test and x[2] test. Findings showed enamel defects of the first permanent molars in children who born by cesarean delivery were significantly more than children born by normal vaginal delivery [70% versus 40.8%]. But there weren't any significant relationship between the prevalence of enamel defects in two types of cesarean [30% versus 33%]. According to results, it is necessary to explain the importance of cesarean as a cause of effective factor on child's first permanent morals and have to aware dentists and parents

[Prevalence of nursing caries and associating factors in 2-4 year olds children]

Introduction: Nursing caries is a specific form of rampant caries affecting the primary teeth of infants as a result of improper nursing bottle habits and/or prolonged unrestricted bottle and breast-feeding. The clinical feature is distinctive in that the maxillary incisors are the most affected. This condition can lead to pain, infection, and interference with eating and expensive dental treatment

Objective: The purpose of this study was to determine the prevalence and associating factors of nursing caries between 2-4 year-old children in Talesh in 1382

Materials and Methods: In this cross-sectional study 261 children aged 2-4 years were selected through a multistage random sampling and examined. Data collection was done by a questionnaire consisting of anterior teeth. Besides dmft [decayed, missed and filled teeth] was evaluated. Data analysis was done with SPSS 11.5 software and X[2] square was used

Results: Prevalence of nursing caries in this sample was 28%. There was a significant correlation between nursing caries and sex, tooth brushing habit, parent's educational state, feeding with liquid sweetened with sugar, cleaning the teeth after feeding and snack eating. There wasn't a significant correlation between visiting the dentist, using the sweetened pacifier, bottle-feeding and breast-feeding with nursing caries. 36.4% of children were caries free. The mean of dmft was 7.86 in nursing caries cases and 1.79 in others [P<0.05]

Conclusion: The prevalence of nursing caries in this community is high. It's necessary to educate parents about controlling the associating factors of nursing caries

[ prevalence and etiology of anterior crown fracture of anterior permanent teeth]

Introduction: Treatment and follow up of traumatized teeth has ever been the concern of many dentists throughout the world. The matter sounds more concerning when the traumatized tooth is a permanent anterior tooth. Regarding to the importance of anterior permanent teeth in mastication, speaking and esthetic, and high prevalence of crown fracture in traumatic injuries of the permanent teeth, we decided to do this study

Objective: The aim of this study is to survey the etiology and prevalence of crown fracture of anterior permanent teeth in 2nd-5th grade children of primary school in Rudsar

Materials and Methods: The study was done by a descriptive and cross-sectional method. The sample consisted of 700 students of 2nd - 5th grade of primary school were randomly selected from 21 schools in Rudsar. Examination was done in natural light and the information about types of crown fracture, number of traumatized tooth, rate of over jet and over bite, lip seal, etiology of trauma and if treatment, registered in a questionnaire. The data were analyzed with SPSS software and Chi-Square test

Results: The prevalence of crown fracture among anterior teeth was 10.3%. The ratio of male to female patients was 1.1/1 Maxillary central incisors were most affected [83.5%] and the most common type of crown injury was enamel fracture [76.4%]. Most injuries occurred at home [50%] and in summer [37.4%]. Falls were the most frequent cause of dental trauma [37.5%]. There was a tendency for children with an increased over jet, deep bite, open bite and lip incompetency to have experienced dental injuries

Conclusion: Considering the importance of anterior teeth and more frequency of trauma in summer, preventive education programs should be instituted in the region, directed at parents and schoolteachers, to inform them about the problems of dental trauma and to obtain cooperative attitude in treatment and good motivation