Dear Editor, Oral soft and hard tissue conditions are two equally important aspects of dental sciences. There are numerous studies on dental caries as the most prevalent infectious disease (1). There are also several surveys pertaining to acquired oral soft tissue lesions and their causative factors. One of these factors is Smokeless Tobacco (ST). Smokeless tobacco includes a variety of tobacco products that are consumed by chewing, keeping in the mouth, or sniffing rather than smoking. Smokeless tobacco products are used by 356 million people in over 140 countries in the world. Most ST users (82%) live in Southeast Asia where the use of ST is incorporated with cultural traditions (2).....

Dear Editor, The many joint cosmetic surgeries in Iran are known as rhinoplasty. Iran is one of the countries where the highest rate of rhinoplasty is performed. In previous years, the rate of rhinoplasty was significantly higher in women than in men. However, the change that has taken place today is that rhinoplasty is more common in men, and the difference is insignificant. More recently, young men are also pursuing rhinoplasty, some for the second or third time..

Introduction: Air weapons are used for sport, hunting, firearm training or just for fun, especially by teenagers, worldwide. These weapons are generally regarded as toys, and injuries from these weapons are thought to be harmless by users, parents and even officials. Improvements in weapons technology make the penetration power of these toys similar to conventional hand guns. To increase awareness about the serious injuries associated with these guns.Case Presentation: The medical records of four teenage boys shot by air weapons between January 2012 and January 2013 in Mersin, Turkey, were retrospectively reviewed in this study. Of the four boys, two needed prompt thoracic intervention due to pneumo/hemothorax, one needed urgent abdominal exploration due to pneumoperitoneum and bleeding from the spleen and one was treated conservatively.Conclusions: Air weapons can cause serious injuries among children. Increased public awareness, limitations to their usage and strict legislation are needed to protect children.

Background: The term "athlete’, s heart" is used to describe physiological changes occurring in the heart of a sportsperson. In contrast to young athletes, there is little data on the physiological changes in children during sport activities. The present study was conducted to compare tissue Doppler echocardiographic indices in adolescent athletes and controls. Methods: In a case-control study done in Mashhad, Iran in 2018, 60 male adolescent athletes and 60 healthy individuals as controls were entered. All subjects were examined by a pediatric cardiologist using echocardiography to compare tissue Doppler Echocardiographic indices between case and control groups. Data analysis was done Using SPSS. 20. The significance level was<5%. Results: Age, weight, height, heart rate and fractional shortening at baseline were not different between the two groups. In the athletes group, Ejection fraction (EF) was greater compared to the control group, while Systolic Blood Pressure (SBP) and Body Mass Index (BMI) were lower. Univariate analysis of Mitral waves showed that athletes presented greater A, E and E/E` ratio than controls and E` and S are greater in controls than in athletes. In relation to septal waves, only E` was higher in controls. In relation to tricuspid waves A, E, E`/A`ratio and E/E` ratio were higher in athletes as compared to the controls. Conclusion: As a useful imaging tool, echocardiography can be employed to detect underlying heart disorders that may threaten people who exercise. However, better identification of individuals at risk of heart attack or other irreversible cardiac damages requires greater knowledge of the pathophysiology of cardiac adaptation to training.

Adolescents are at risk for many serious health problems including drugs, alcohol, depression and sexually transmitted diseases. Research on these issues is important to establish more effective prevention programs and therapies. However, research concerning adolescents faces challenges for several reasons. First, despite their developing maturity, generally people need to be at least 18 years before they may decide for themselves to participate in research. Below that age, parental permission is generally necessary. However, adolescents may not be willing to participate in research in sensitive topics if their parents are informed about their participation. Second, adolescents vary in their maturity, independence, and ability to make informed decisions. Although they may wish to make their own decisions, adolescents usually benefit from parental guidance. Finally, many of teenagers are exposed to the public health risks and many of them are abused by political aims and research on these problems is often socially controversial.Taking into account the mean age of the Iranian population and also huge number of observational studies which are being done among Iranianadolescents on one hand and the absence of researchers’complete familiarity with the 26 Code relating to the protection of human subjects in medical researchadvised by Ministry of Health and Medical Education in 2010 on all the Universities of medical sciences across the country - the main purpose of this study is to summarize those issues and ethical considerations in observational studies on adolescents which should be taken into consideration.

Iran is an ancient country with the cultural background of 6000 years of civilization and 2500 years of recorded history and rich literature in both written and oral forms, the heritage from which the children have benefited a lot. Considering that the course literary development in each country is under the impact of its cultural, social, political, and economical conditions, children's literature cannot be excluded from this trend. It is divided into four periods which have had falling and rising courses, different themes and styles, and numerous kinds of literature such as translated and also classical works. In each period there have been seminars, exhibitions in the domain of poetry, picture, literary criticism, kinds of magazines and newspapers apprehensible to children and teenagers. Finally, by introducing new technology in the life of the children and its effect on the written literature, and the stance of Iranian children's literature in present condition, that's, entering the fourth level; we can witness the creation of independent teenagers' literature.

The present study aims to prepare and standardize a teenagers' gender identity questionnaire for 15-18 year-old teenagers of Tehran city. The questionnaire included 91 questions measuring four scales, including successful identity, premature identity, serotinous identity and troubled identity. 580 high-school students (454 females and 126 males) of Tehran city in the school year 2010-2011 were randomly selected as the sample volume. The construct validity of the questionnaire was assessed by factor analysis of main components and varimax rotation, and four factors were derived from the questionnaire. Moreover, Bennion and Adams' identity status measurement questionnaire and Bem's sex role questionnaire were used to measure the criterion validity of teenager's gender identity questionnaire. The validity coefficient of the questionnaire and its scales was determined by Cronbach's alpha coefficient to fluctuate between 0.73 and 0.82. After the marks received by male and female students were compared, the questionnaire norms for each scale were calculated and recoded on the basis of T and Z scaled marks.