# Evaluation and Comparison of Cortisol Levels in Saliva and Hair among Dental Students
## 1 Introduction  
The steroid cortisol hormone is produced and secreted by the adrenal glands. Cortisol affects several body processes, including nervous system activity, immune system performance, protein, lipid, and glucose metabolism, bone growth, and blood pressure management. It is crucial for a healthy physiology and is primarily released in response to stress [1, 2]. Another chemical that our brain releases in reaction to stress and frightening situations is adrenocortic hormone. Further, adrenal glands are stimulated to release cortisol and adrenaline, which results in a surge of new energy and strength [3]. Cortisol is the most common glucocorticoid in non-human primates, other animals, and humans. Although the role of cortisol in stress-related processes in both humans and animals is well-known, little is known about how well it can reflect stress levels over a prolonged period of time. Cortisol testing, which looks for increased or decreased cortisol production, is used to evaluate the pituitary and adrenal glands' functionality. Additionally, tests could be advised if a woman has irregular periods or grows more facial hair or if a child has short stature and slow growth [4, 5].  
Up until recently, most studies concentrated on the cortisol response from urine, serum, or saliva samples. Both saliva and serum can be used to determine the cortisol level at a specific time. Therefore, such samples can be used to test for acute changes, but both methods are highly challenging to fully evaluate prolonged systemic exposure to cortisol due to considerable daily physiological variations [6; 7]. In healthy individuals, cortisol levels are highest in the morning and gradually decrease throughout the day. Because it is a noninvasive approach that generates no additional stress, research utilizing this technology shows that, although cortisol determination in saliva has indisputable advantages over plasma, its significance as a biological marker is applicable more to acute stress situations than to chronic processes [6; 7; 8].  
Recently, it has been suggested that one technique to evaluate the hormonal status over an extended period is to monitor the cortisol levels in tissues like hair and nails. Hair analysis has been used for years by toxicology and forensic science to monitor exposure to exogenous substances. Because it can reveal extensive periods of time and reveal information about previous exposure to hazardous substances, hair is valued as a result [9; 10]. It has advantages over body fluids, such as detection over months, noninvasive sampling, ease of storage, and strong resistance to breakdown. The introduction of hair analysis in the field of psychobiology is the result of these and other causes. Recently, cortisol analysis in hair segments has been employed in biomedical research, and it has proven to be a viable biological marker for longer periods of stress exposure than the traditional 24 h time frame [9; 10; 11; 12].  
Stress is very common among dental school students. Due to their background of high accomplishment and excellence in prior academic endeavors, as well as the fact that excellence is the standard at dentistry school, dental students have a tendency toward perfectionism, which contributes to the perception of stress [13; 14]. Student performance may suffer when stress levels rise. Stress may also impair a student's ability to perform professionally by impairing their ability to pay attention, concentrate, make decisions, and develop strong patient relationships [15; 16]. According to a recent study, students' bodies often experience an increase in cortisol when they suffer an academic setback, such as receiving a poor grade. A day later, it returns to normal levels for many youngsters, but for some, it remains high [17].  
According to the aforementioned factors, the current study was designed with the goals of comparing and evaluating the levels of cortisol variation in saliva and hair samples taken from young adult dental students at two time intervals.