Expert article Mouth and breathing
Dry mouthWhy the mouth dries out
Dry mouth in the morning, thirst at night, a tongue that sticks to the palate? Here you will learn what saliva does, what can cause dry mouth, from medications to mouth breathing, when you should have it checked and why a sealed oral cavity is a pattern of breathing, swallowing and head balance.
Does this sound familiar?
Is your mouth dry even though you drink enough?
What applies to you?
Tap whatever applies to you.
If several of these points apply, it is worth looking at where the dryness comes from. Medications and medical conditions need to be checked by a doctor. If neither is the case, the cause, in our view, is usually the way you breathe, especially at night. This pattern can be trained.
What happens at nightThe most common causesThe key points at a glance
- Saliva forms a wafer-thin film over more than 200 square centimetres of mucous membrane. It protects the teeth and mucous membrane, makes food easier to swallow and almost dries up during sleep.
- Dry mouth has many possible causes: medications, conditions such as diabetes or Sjögren’s syndrome, age and mouth breathing, especially at night. Persistent dryness should be checked by a doctor, and you should not stop prescribed medications on your own.
- If your mouth is dry mainly in the morning, in our view this is usually due to an open mouth at night. A sealed oral cavity results from the interplay of breathing, swallowing and head balance, and this pattern can be trained.
Video
Dry mouth: why a glass of water doesn’t change anything
Das Video lädt erst nach dem Klick. Dann werden Daten an YouTube (Google) übertragen.
Saliva
What saliva does every day
You only notice saliva when it is missing. Yet it works continuously, and over a surprisingly large area.
Three large pairs of glands supply most of the saliva: the parotid gland in front of the ear, the submandibular gland at the angle of the jaw and the sublingual gland in the floor of the mouth. In addition, there are several hundred small glands in the mucous membrane, controlled by the autonomic nervous system. At rest, little saliva flows; when tasting and chewing, the flow briefly rises up to tenfold1.
is the average inner surface area of the mouth, determined from impressions of 20 adults2
is how thin the saliva film covering this surface is, calculated in the same study2
is the salivary flow during sleep. The protective effect of saliva is therefore largely absent at night3
This film protects the teeth from caries and acid damage and the mucous membrane from fungal infection and friction; it buffers acids and makes food swallowable. It is not evenly distributed. The secretions of the glands mix only incompletely, and how quickly the film moves across a given spot varies considerably within the mouth3.
Xerostomia
Dry mouth: how to recognise it
Dry mouth is, first of all, a feeling. Whether less saliva is actually flowing is a separate question.
The technical term for the feeling of a dry mouth is xerostomia. It is a complaint that you describe, and it does not necessarily match the amount of saliva that can be measured4. It is common all the same. A review pooled 29 population-based studies. Across all of them, 22% of respondents reported a dry mouth, and considerably more among older people5.
Sticky feeling
Your tongue and cheeks stick together and speaking is harder, especially in the morning.
Thirst at night
You wake up and need a sip of water, sometimes several times a night.
Dry lips
Your lips are chapped or cracked, and the corners of your mouth split more easily.
Difficulty swallowing
Dry bread or biscuits are hard to form into a mouthful and swallow.
Coating and bad breath
In the morning your tongue is coated and your breath smells unpleasant.
The lips are often the first thing you notice. If breath flows over them for hours, they become chapped and crack. Lip care relieves this, but it does nothing about the airflow.
So pay attention to the pattern behind it. If your lips are dry mainly in the morning and this improves over the course of the day, that suggests your mouth was open during the night.
When is your mouth driest?
Causes
Causes of dry mouth: one feeling, many pathways
Many different things can lie behind a dry mouth. Some need medical attention, others are part of everyday life.
Medication comes first. A working group of the World Workshop on Oral Medicine systematically reviewed the literature up to 2013 and compiled a list of active substances that demonstrably affect the salivary glands or trigger the feeling of a dry mouth6.
with a higher level of evidence, plus 50 with a moderate level, caused dry mouth or a salivary gland disorder6
of the international drug classification were represented, mainly drugs for digestion, the heart and circulation, the urinary tract, the nervous system and the respiratory tract6
Sjögren’s syndrome
An autoimmune disease that mainly affects the salivary and tear glands. Dryness of the mouth and eyes at the same time is typical; those affected are predominantly middle-aged women7.
Diabetes
In all the studies of a Spanish review, people with diabetes complained of a dry mouth more often than people without diabetes. However, the quality of the studies was low8.
Age
A meta-analysis of 47 studies found lower salivary flow in older adults, and this was also independent of medication9.
Radiation
Radiotherapy to the head and neck area and some cancer therapies impair the salivary glands.
Tension
The parasympathetic nervous system mainly controls the fluid in saliva, the sympathetic nervous system mainly the proteins1. More on the resting side of the nervous system in the article on the vagus nerve.
With age, several factors often come together. Salivary flow decreases, more medication is taken, and many people drink too little. Alcohol in the evening and smoking dry the mouth out further. That is why it is worth reviewing your medication plan together with your doctor’s practice or pharmacy.
If the dry mouth persists for weeks, has appeared suddenly, or is accompanied by dry eyes, severe thirst or frequent urination, have it checked by a doctor. If you take medication, do not stop taking it on your own. Your practice will weigh up with you whether there is an alternative.
Dry mouth at night
Dry mouth in the morning: what happens at night
Many people notice the dryness mainly when they wake up. This has to do with sleep itself and with the route the air you breathe takes.
During sleep, the body sharply reduces saliva production, and you swallow much less often10. A Canadian survey shows how common dry mouth at night is. In it, 23% of respondents said they woke up at night with a dry mouth and needed to drink11. A research group in New Zealand measured what happens in the mouth during this time.
was the mean value in the mouth during the day, measured in ten healthy adults12
during sleep with normal breathing through the nose12
during sleep with a nose clip, i.e. with mouth breathing. The value fell further and stayed low for longer12
So mouth breathing during sleep makes the mouth not only drier but also more acidic, which the authors consider a possible factor in acid damage and caries12. A survey of around 1,250 adults in Israel shows how closely a dry mouth in the morning and an open mouth at night are linked. The proportion who woke up with a dry mouth almost every morning was13:
of the comparison group from a general health check-up13
of people who snored without having breathing pauses13
of people with obstructive sleep apnoea, rising with severity to 40.7%13
The authors suspect that more sleep time with the mouth open is the explanation13. So a dry mouth in the morning tells you something about how you breathe at night. If you snore loudly and people tell you about pauses in your breathing, read the article on snoring and sleep apnoea. In that case, an assessment in a sleep laboratory comes first.
Mouth breathing
When air flows over the mucous membrane
Mouth breathing does more than dry things out. It also changes where saliva reaches and what happens on the mucous membrane.
With every breath through the open mouth, air flows over the tongue, palate and teeth. It is mainly water that evaporates, leaving behind a thickened film that spreads less well. A measurement at six sites in the mouth, carried out in Seoul, shows where it runs short first. The film was thinnest on the front of the hard palate and thickest on the front of the upper surface of the tongue. In a dry mouth, the protein content of the remaining fluid also rose14.
What matters is not only how much saliva flows, but where it arrives.Salivary flow within the normal range does not rule out uneven wetting. That is why some areas become dry even though the glands are working.
A study from São Paulo involving 61 adolescents, 30 of them mouth breathers, shows this too. There was no difference in the flow rate, buffering capacity or protein content of their saliva. The only value that was higher in the mouth breathers was free sialic acid, which the authors considered an indication of more bacteria in the mouth15. So if you only measure the quantity, you miss what is happening on the mucous membrane.
A review from Belo Horizonte evaluated eleven studies of children and adolescents. Mouth breathing was associated with more dental plaque, more frequent bleeding gums and changes in the gums; for tooth decay the association was weaker16. The studies only look at a single point in time. In our view, night-time breathing is nevertheless too rarely considered in dental problems, even though it is usually part of the conditions under which teeth and gums find themselves every night, in a drier and more acidic mouth.
The mouth is open
During sleep the lower jaw drops, the tongue lies low, and the air takes the route through the mouth.
The film dries out
Hour after hour, water evaporates, and at night hardly any saliva replaces it.
The protection weakens
The thickened film tears away at thin spots.
The environment changes
The mouth becomes more acidic, and teeth and gums are under greater strain.
You wake up with a dry mouth
The glass of water moistens for a few minutes and interrupts your sleep in the process. It does not change the route the air takes.
3D film
Nasal breathing during sleep: the oral cavity stays sealed
The animation shows one breath during sleep, lying on the back, in a side section. The air takes the route through the nose, and none flows over the tongue and palate.
The triad
A moist mouth needs a sealed oral cavity
Intention does not decide whether your mouth is open at night. The pattern your nervous system has stored does.
Breathing
When you breathe through your nose, the air is warmed and humidified there, and your mouth remains a closed, moist space. For this, your nose needs to be clear. If one side is blocked, this is often due to the nasal cycle.
Swallowing
With every swallow, the tongue presses against the palate and redistributes the saliva, anywhere from several hundred to a thousand times a day. The starting point is the tongue reference position. More in the article on swallowing.
Head balance
When the head is balanced above the body, the lower jaw hangs relaxed and the lips rest loosely together. If the head moves forward, in our view the mouth opens more easily.
If your mouth is open at night, in our view the cause usually lies in this interplay and not in lips that are too weak. Muscles that are not integrated into their function are not used and lose tone. Muscles that are used in everyday life retain it.
Something similar applies to the salivary glands. In experimental studies they regressed when they were barely stimulated for a long time, for example on an exclusively liquid diet, and recovered as soon as the stimulus returned1.
The pattern deviates
Mouth breathing, a low-lying tongue and disturbed head balance, often since childhood.
The body compensates
The nervous system stores the detour as the preferred pattern, during the day as well as during sleep.
The structure follows
Over the years, palate shape, tooth position and posture adapt.
Only then do symptoms appear
In many people, a dry mouth in the morning is one of the first noticeable consequences. When it appears and how pronounced it is depends on the extent, the duration and the person’s age.
No one has yet specifically studied whether saliva and the mucous membrane change once nasal breathing has been restored. The absence of a study does not mean that the connection does not exist, only that it has not been tested. What is established is that mouth breathing during sleep makes the mouth drier and more acidic.
Context
Relieving dry mouth and addressing the cause
There are many remedies for the dry feeling. They have their place, as long as it is clear what they do.
A review from Boston lists the common approaches: products that stimulate saliva flow, gels and sprays for the mucous membrane, saliva substitutes and, in cases of pronounced dryness, prescription medicines that stimulate the glands4. With conditions such as Sjögren’s syndrome or after radiotherapy, they are often indispensable.
Relieving the symptom
- Water in small sips, including at night
- Saliva substitutes, gels or sprays from the pharmacy
- Humidifying the air in the bedroom
- Lip care for chapped lips
Addressing the cause
- Checking medications with your doctor’s practice or pharmacy
- Having conditions such as diabetes or Sjögren’s treated
- Clearing your nose and keeping it clear
- Training lip closure and nasal breathing as a pattern
The two are not mutually exclusive. Relief makes the night more bearable, but it does not change the cause.
Sugar-free chewing gum or lozenges stimulate saliva flow for a while. In our view, however, they count as oral habits that interfere with practising the new pattern during training. So use them sparingly.
We do not recommend taping your mouth shut at night. A strip holds it closed from outside, but it does not change the pattern that opens it, and if your nose is blocked, it takes away the alternative route. More on this in the article on Mouth Taping.
Training
Training lip closure and nasal breathing
There is no intention during sleep. What runs there is whatever is stored as a pattern, and a pattern changes through precise, frequent repetition. That is why our approach is training the basic functions of breathing, swallowing and head balance. It creates the conditions for the mouth to stay closed from within and for the air to take the route through the nose.
In FaceFormer training, the FaceFormer sits in the oral vestibule, behind the lips and in front of the teeth. The tip of your tongue rests on the small ridge behind your upper front teeth, you breathe through your nose, and your head is balanced upright.
In the basic exercise, you press the lip wedge together with your lips, bite down briefly with your back teeth and swallow once. The negative pressure draws the tongue to the palate, and the oral cavity is sealed.
You do not practise lips, tongue, breathing and head separately, but within the same sequence.
At night you wear the FaceFormer ZERO once you have mastered the basic exercise, from around the third week. Your lips hold it in place themselves. At first it will slip out more often. More on this under night-time use.
- From day 1
Basic exercise
A few minutes three times a day with the FaceFormer ZERO; you increase the repetitions week by week.
- From around week 3
Pull exercise and night
The pull exercise is added. At night you wear the ZERO once you have mastered the basic exercise.
- After a few weeks
Switching to the ONE
During the day you train with the FaceFormer ONE. It is made of firmer material, and its size and shape match the ZERO. At night you continue to use the ZERO.
- From around week 6
Breathing exercise
The breathing exercise combines the training with calm nasal breathing and breathing pauses that get longer over time.
- Over months
The pattern runs by itself
The exercise manual allows six to twelve months until the new sequences run without thinking.
The free FaceFormer app guides you through the basic exercises, and you can find all modules on the exercise pages. If your mouth stays dry despite a clear nose and closed lips, have other causes checked by a doctor. Children follow their own exercise plan; find out more under FaceFormer for children.
Everyday life
Dry mouth: what you can do yourself
Brush your teeth before going to sleep
At night, hardly any saliva flows, so its protection is largely lost. That is why brushing right before going to sleep is particularly important3.
Drink throughout the day
Spread your drinking across the day instead of catching up at night. Water or unsweetened tea is the best choice; alcohol in the evening dries you out even more.
Lips closed, tongue up
Your lips rest loosely together, with the tip of your tongue at the reference point. Check this several times a day, for example when you unlock your phone.
Check your nose before sleeping
Briefly close one nostril, then the other. If one side is narrower, this is often the nasal cycle. If both sides are blocked for a long time, have it checked.
Chew thoroughly
Chewing and tasting strongly stimulate the flow of saliva. Take your time when eating; solid food challenges the glands more than purées.
Do not stop prescribed treatment on your own
If you suspect a medication is the cause, talk to your doctor’s practice or pharmacy. The training can be combined with medical treatment.
Questions
Frequently asked
What is dry mouth?
Dry mouth, known medically as xerostomia, is the sensation of a dry mouth. It can go along with a measurably reduced salivary flow, known as hyposalivation, but it does not have to. In population-based studies, around one in five people report it, older people more often.
Why is my mouth dry in the morning?
During sleep, hardly any saliva flows, and you swallow less often. If your mouth is also open, the air you breathe dries out the saliva film over several hours. In a study from Israel, a dry mouth in the morning occurred almost ten times as often in people with sleep apnoea as in the comparison group.
Which medications cause dry mouth?
A great many. A systematic review found over 100 active substances that trigger dry mouth or affect the salivary glands, from the areas of digestion, heart and circulation, urinary tract, nervous system and respiratory tract. Do not stop a prescribed medication on your own; instead, talk to your practice about possible alternatives.
When should I see a doctor about dry mouth?
If it persists for weeks, appears suddenly or comes with dry eyes, severe thirst, frequent urination, difficulty swallowing or swollen salivary glands. These can be signs of conditions such as diabetes or Sjögren’s syndrome, which need medical treatment.
Does drinking a lot help with a dry mouth?
If you drink too little, yes. But if you drink several times a night, you relieve the dryness for a few minutes and interrupt your sleep in the process. It does not change the air that flows over the mucous membrane. In our view, frequent thirst at night is therefore a reason to look at night-time breathing.
Can mouth breathing promote tooth decay and gum inflammation?
Studies of children and adolescents show more dental plaque and bleeding gums with mouth breathing; for tooth decay the association is weaker. In addition, during sleep with an open mouth, the mouth becomes drier and more acidic. The studies do not show what came first. In our view, night-time breathing should nevertheless be considered in gum and tooth problems.
What does stress have to do with a dry mouth?
The salivary glands are linked to the autonomic nervous system. The parasympathetic nervous system mainly provides the fluid; under tension, saliva becomes scarcer. In addition, many people breathe more shallowly and through the mouth when under stress. More in the article on the vagus nerve.
Does mouth taping help with dry mouth?
We do not recommend it. A strip of tape only holds the mouth closed from the outside and does nothing to change the pattern that opens it at night. You can read what studies show in the article on mouth taping.
Can I train with the FaceFormer despite having a dry mouth?
As a rule, yes. In long-term mouth breathers, the mucous membrane is sometimes irritated at the beginning. In that case, take a short break and continue with fewer repetitions or with the softer FaceFormer ZERO. If you have acute inflammation in your mouth, talk to your practice beforehand.
How long does it take until the mouth is less dry in the morning?
In our experience, many people for whom mouth breathing is the reason notice after a few weeks of consistent training with night-time use that their mouth is less dry in the morning. There is no fixed timeframe; you have to keep at it. The exercise manual expects six to twelve months until the new pattern runs without thinking.
More articles from the knowledge section
Experiences on this topic
Where to go next
Sources
- Proctor GB, Carpenter GH (2007). Regulation of salivary gland function by autonomic nerves. Autonomic Neuroscience 133(1):3-18. PMID 17157080. Source
- Collins LM, Dawes C (1987). The surface area of the adult human mouth and thickness of the salivary film covering the teeth and oral mucosa. Journal of Dental Research 66(8):1300-1302. PMID 3476596. Source
- Dawes C (2008). Salivary flow patterns and the health of hard and soft oral tissues. Journal of the American Dental Association 139 Suppl:18S-24S. PMID 18460676. Source
- Villa A, Connell CL, Abati S (2015). Diagnosis and management of xerostomia and hyposalivation. Therapeutics and Clinical Risk Management 11:45-51. PMID 25653532. Source
- Agostini BA, Cericato GO, Silveira ERD, Nascimento GG, Costa FDS, Thomson WM, Demarco FF (2018). How Common is Dry Mouth? Systematic Review and Meta-Regression Analysis of Prevalence Estimates. Brazilian Dental Journal 29(6):606-618. PMID 30517485. Source
- Wolff A, Joshi RK, Ekström J et al. (2017). A Guide to Medications Inducing Salivary Gland Dysfunction, Xerostomia, and Subjective Sialorrhea: A Systematic Review Sponsored by the World Workshop on Oral Medicine VI. Drugs in R&D 17(1):1-28. PMID 27853957. Source
- Brito-Zerón P, Baldini C, Bootsma H et al. (2016). Sjögren syndrome. Nature Reviews Disease Primers 2:16047. PMID 27383445. Source
- López-Pintor RM, Casañas E, González-Serrano J, Serrano J, Ramírez L, de Arriba L, Hernández G (2016). Xerostomia, Hyposalivation, and Salivary Flow in Diabetes Patients. Journal of Diabetes Research 2016:4372852. PMID 27478847. Source
- Affoo RH, Foley N, Garrick R, Siqueira WL, Martin RE (2015). Meta-Analysis of Salivary Flow Rates in Young and Older Adults. Journal of the American Geriatrics Society 63(10):2142-2151. PMID 26456531. Source
- Orr WC, Heading R, Johnson LF, Kryger M (2004). Review article: sleep and its relationship to gastro-oesophageal reflux. Alimentary Pharmacology and Therapeutics 20 Suppl 9:39-46. PMID 15527463. Source
- Thie NM, Kato T, Bader G, Montplaisir JY, Lavigne GJ (2002). The significance of saliva during sleep and the relevance of oromotor movements. Sleep Medicine Reviews 6(3):213-227. PMID 12531122. Source
- Choi JE, Waddell JN, Lyons KM, Kieser JA (2016). Intraoral pH and temperature during sleep with and without mouth breathing. Journal of Oral Rehabilitation 43(5):356-363. PMID 26666708. Source
- Oksenberg A, Froom P, Melamed S (2006). Dry mouth upon awakening in obstructive sleep apnea. Journal of Sleep Research 15(3):317-320. PMID 16911034. Source
- Lee SK, Lee SW, Chung SC, Kim YK, Kho HS (2002). Analysis of residual saliva and minor salivary gland secretions in patients with dry mouth. Archives of Oral Biology 47(9):637-641. PMID 12243967. Source
- Weiler RM, Fisberg M, Barroso AS, Nicolau J, Simi R, Siqueira WL Jr (2006). A study of the influence of mouth-breathing in some parameters of unstimulated and stimulated whole saliva of adolescents. International Journal of Pediatric Otorhinolaryngology 70(5):799-805. PMID 16242785. Source
- Kimura ACRS, de Arruda JAA, Drumond VZ, Martins-Júnior PA, Mesquita RA, Abreu LG (2026). Dental Caries and Periodontal Outcomes in Mouth-Breathing Children and Adolescents: A Systematic Review. International Journal of Paediatric Dentistry 36(1):24-32. PMID 40739849. Source
Get started
Ready for the training?
The free FaceFormer app guides you through the basic exercises, counts along and reminds you of your sessions. If you wish, a practice from the practitioner directory can support you.
FaceFormer ZERO + ONE
Both material hardnesses for getting started, day and night. The set for adults.
FaceFormer ZERO
The softer FaceFormer for getting started, for children and for the night.
FaceFormer ZERO Children’s Set
ZERO with hygiene box, plush bag and success book with stamp.
FaceFormer training aims to restore the physiological setting of the basic functions of breathing, swallowing and head balance, with lip closure and the tongue reference position, thereby creating the conditions under which symptoms can improve. It does not replace a medical assessment. You can find practitioners near you in the practitioner directory.
