Can a mouth film reveal the secret to restful sleep?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age between 18 - 35 years (inclusive) * Body-Mass-Index (BMI): 18.5 \< BMI \< 25 * Non-nicotine user status * Habitual consumption of 5 or fewer alcoholic beverages / week * Habitual consumption of 3 or fewer caffeinated beverages / day * Habitual average sleep duration 7-9 h / night * Normal or corrected-to-normal vision * Insomnia severity Index (ISI) Score: ISI \< 8 * Ability to understand and speak German language * Normal hearing ability (applies only to Sleep Study Part) * Ability and willingness to provide informed consent as documented by dated signature Exclusion Criteria: * Present use of medication that may interfere with sleep or study drugs * Travel across 3 or more time zones within 3 months of study start * Habitual napping * Extreme chronotype, determined by reduced Morningness-Eveningness Questionnaire (rMEQ) score: 8 \< rMEQ \> 21) * Shift working within 2 weeks prior to the screening visit * History of or presence of a trauma- or stressor-related disorder * Serious acute or chronic neurological, mental, or general medical conditions that, in the opinion of the investigator, may pose a risk to participation or affect study measurements * History of or presence of a sleep wake disorder * Use of illicit drugs (positive urinary drug screening) * Male participants who are not vasectomised for at least 6 months prior to dosing and who are sexually active with a female partner of childbearing potential not willing to use one of the following acceptable contraceptive methods from the first dose and for 3 months after the last dose: Use of condom and/or hormonal contraceptive (e.g., oral, patch, depot injection, implant, vaginal ring, intrauterine device) or non-hormonal intrauterine device used for at least 4 weeks prior to sexual intercourse for the female partner; * Male participants (including men who have had a vasectomy) with a pregnant partner not willing to use a condom from the first dose and for 3 months after the last dose. * Male participants not willing to abstain from sperm donation for 3 months after the last dose * Females of childbearing potential who are sexually active with a non-sterile male partner (sterile male partners are defined as men vasectomised at least 6 months prior to the first study drug administration) not willing to use one of the following acceptable contraceptive methods throughout the study and for at least 3 months after the last study drug administration: Simultaneous use of condom and hormonal contraceptive (e.g., oral, patch, depot injection, implant, vaginal ring, intrauterine device) or non-hormonal intrauterine device used for at least 4 weeks prior to sexual intercourse for the female partner; \- Females of non-childbearing potential who are neither: Post-menopausal (status defined as an absence of menses for at least 12 months prior to the first study drug administration); or Surgically sterilized (complete hysterectomy or bilateral oophorectomy at least 3 months prior to the first study drug administration) * Faints at the sight of blood (applies only for the pharmacokinetic-part of the study) * Has participated in a study \< 30 days or a study such as this (i.e., experimental trauma) at all.