There are studies claiming that sedation accounts for 40 percent to 50 percent procedure-related complications, that is why this process has attracted attention.Airway obstruction, apnea and hypotension are not uncommon during sedation and require the presence of health professionals who are suitably trained to detect and manage these problems. Aside from the suppression of respiration, risks also include unintended levels of sedation, postoperative somnolence, aspiration, and adverse reactions to sedation medications. Complications could also include perforation, bleeding, and the stimulation of vasovagal reflexes. To avoid sedation risks, care providers conduct a thorough pre-sedation evaluation and this process includes pre-sedation history and physicals with emphasis on the determining characteristics that indicate potential risks to the patient and potential difficult airway management. This process can also reveal if the sedation period needs to be prolonged or additional therapeutic procedures are required.
Levels of sedation
Sedation scales are used in medical situations in conjunction with a medical history in assessing the applicable degree of sedation in patients in order to avoid under-sedation (the patient risks experiencing pain or distress) and over-sedation (the patient risks side effects such as suppression of breathing, which might lead to death).
Examples of sedation scales include MSAT (Minnesota Sedation Assessment Tool), UMSS (University of Michigan Sedation Scale), the Ramsay Scale (Ramsay, et al. 1974) and the RASS (Richmond Agitation-Sedation Scale).
Minimal sedation - normal response to verbal stimuli.
Moderate sedation - purposeful response to verbal/tactile stimulation. (This is usually referred to as "conscious sedation")
Deep sedation - purposeful response to repeated or painful stimulation.
General anesthesia - unarousable even with painful stimulus.
In the United Kingdom, deep sedation is considered to be a part of the spectrum of general anesthesia, as opposed to conscious sedation.
In addition to the aforementioned precautions, patients should be interviewed to determine if they have any other condition that may lead to complications while undergoing treatment. Any head, neck, or spinal cord injuries should be noted as well as any diagnosis of osteoporosis.
The most common standard conscious sedation technique for adults is intravenous sedation using Midazolam. This requires a needle to be put into a vein to deliver the medication, this is known as an IV cannula.
Reduced dental anxiety and phobia
Traumatic or prolonged dental procedures
Patients with gag reflex
Medical conditions potentially aggravated by the stress of dental treatment
Special care (mild intellectual or physical disability)
Some disorders involving its spasticity due to its muscle relaxant properties
Psychologically immature individuals
Patients unable to provide a suitable escort
Difficult oral surgery or prolonged surgical procedure
Muscle diseases or diseases which cause muscle wastage
ASA III or above
Allergy or hypersensitivity to benzodiazepines
Pregnancy and breast feeding
History of psychiatric disorders
Kidney or liver dysfunction
Acute pulmonary insufficiency
Preexisting respiratory conditions as patients are susceptible to respiratory depression
Alcohol or drug addiction
Lack of visible superficial veins
CNS depressant medications which can alter reaction to sedation 
^Vargo, John (2016). Sedation and Monitoring in Gastrointestinal Endoscopy, An Issue of Gastrointestinal Endoscopy Clinics of North America. Philadelphia, PA: Elsevier Health Sciences. p. 465. ISBN9780323448451.
^Odom-Forren, Jan; Watson, Donna (2005). Practical Guide to Moderate Sedation/analgesia. St. Louis, MO: Elsevier Mosby. p. 84. ISBN0323020240.
^Vargo, John (2016). Sedation and Monitoring in Gastrointestinal Endoscopy, An Issue of Gastrointestinal Endoscopy Clinics of North America. Philadelphia, PA: Elsevier Health Sciences. p. 554. ISBN9780323448451.