99 % of the volume consists of water, 1 % of inorganic and organic substances
|Provides stability of the internal setting of the mouth and maintains the ecological equilibrium of the oral microflora
|Facilitates taste perception
|Protects teeth from caries
Of the disorders of salivary secretion, reduced secretion is the more common problem; increased secretion is only rarely a reason for complaints. To better understand the consequences of insufficient salivation, let’s make a short overview of the functions of saliva:
lubrication – saliva helps in softening the food, creating food bolus, chewing, swallowing, it makes speaking easier, cleans the tissues of the oral cavity and protects teeth from damage.
digestion and taste perception – saliva contains digestive enzymes (amylases and lipases) that initiate the cleavage of starchy substances. It facilitates taste perception of food and other substances.
regeneration of soft tissues – epidermal (EGF) and transforming (TGF) growth factors present in the saliva help in the tissue growth, differentiation and healing of injuries.
maintaining the ecological equilibrium of the oral microflora – saliva contains various antibacterial, antiviral and antifungal compounds instrumental in maintaining the microbial equilibrium and inhibiting bacterial colonization of teeth and soft tissues by altering the microbial adhesion capacity.
buffering activity – the saliva has the capacity to reduce the acidity in the mouth and maintain it on the appropriate level, which reduces the risk of caries. The buffering capacity also protects the upper part of the GIT from the regurgitation from esophagus.
remineralization – saliva protects the teeth and supports remineralization of the enamel as it contains essential minerals, which improves the mineral absorption into the demineralized tissue.
The main specific defence mechanism of the oral mucosa is production of the sIgA. It is an IgA dimer, the molecules of which are connected by a so-called J-chain (joining chain). In addition, it carries a secretory component containing a glycoprotein serving as a transmembrane polymeric immunoglobulin IgA (and IgM) receptor, facilitating the transport of sIgA through the epithelial cell (transcytosis) and its protection from proteolysis.
Saliva is secreted by three pairs of major salivary glands and many minor mucosal salivary glands. The stable moisture of the oral mucosa is maintained predominantly by the minor salivary glands continuously secreting the saliva. On the contrary, the major salivary glands produce saliva mostly after stimulation. Such stimulation most commonly originates in the oral cavity with its mechanoreceptors and chemoreceptors. Salivary production is under physiological circumstances dependent on the degree of activity of the vegetative nerves and that activity is to a large degree given by the degree of mastication activity. The parotid gland produces serous secret, the sublingual and submandibular glands produce mixed saliva. As mentioned above, the salivary glands are innervated by the autonomous nervous system. The parasympathetic nerves into the submandibular and sublingual glands leave the intermediate nerve, run in parallel with the facial nerve across the chorda tympani and enter the glands together with the lingual nerve. The parasympathetic nerves for the parotid gland leave the glossopharyngeal nerve and enter the gland through the auriculotemporal nerve. Sympathetic nerves enter the glands together with the vessels. The nucleus salivatorius in the medulla oblongata serves as the “salivary control centre” and is in turn controlled by another “control centre” in the hypothalamus. Parasympathetic stimulation increases the production while anticholinergic drugs reduce the secretion. Irritation of the sympathetic nervous system results in production of thick saliva.
The examined person is instructed to spit all saliva collecting in the mouth into a graduated cylinder for 15 minutes. The saliva can be neither swallowed nor sucked out from glands. This way, the “resting (unstimulated) salivary flow” is established. Subsequently, the patient is given a paraffin tablet for chewing and the saliva produced while chewing is collected into another graduated cylinder (stimulated salivary flow). Those values are subsequently measured and summed up. Normal values are between 8 and 15 ml per 2x 15 minutes, any smaller values are considered pathological.
Increased salivary production
(ptyalism, sialorrhoea, also hyper/polysialia)
Reduced salivary production
(hyposialia, oligosialia, asialia)
subjective sensation of dryness in the mouth
Disorders of the salivary secretion concern in particular its quantity and can manifest in many diseases of the oral mucosa.
This is an increase of salivary secretion that can occur under physiological circumstances based on conditioned reflexes (mostly pleasant stimulations of taste buds, smell, sight or hearing – Pavlov reflexes). An increased salivary production can be also observed in pregnancy as a result of hormonal and neurovegetative changes accompanying that condition.
Of pathological causes, infections must be mentioned in particular – many acute stomatitides are accompanied by reflex-induced salivation, sometimes combined with painful or difficult swallowing. It regresses spontaneously when the mucosal defects heal and does not require any therapy. Hypersalivation can be also a symptom of injuries to the mouth and salivary glands or their orifices. Other reasons for hypersalivation include poisoning by heavy metal salts (lead, arsenic, mercury) or disorders of the central nervous system (hemiplegia, bulbar palsy). Some medications (pilocarpine, prostigmine, iodides, etc.) can also induce the salivary gland secretion.
Th.: In some cases, it is unnecessary as it would regress spontaneously after the infection is gone; otherwise, a causal treatment according to etiology is indicated. Symptomatic treatment using atropine is possible.
Salivary gland production can be reduced in many pathological conditions. In congenital salivary glands aplasia, the lack of saliva is self-explanatory. Reduced salivary production is observed in deficiency diseases (serious anaemia, avitaminosis), autoimmune diseases (Sjögren syndrome), or in metabolic diseases (diabetes mellitus, hypothyreosis, liver cirrhosis, etc.) where, besides the salivary secretion, reduced HCl production associated with hypoacidity (anacidity) symptoms is often observed. Hyposialia can be also present in advanced atherosclerosis; a likely reason is reduction of the stimulation for salivary production or involution of salivary glands.
Unconditioned production of saliva is usually more affected than the conditioned production. A major reduction of salivary production can be observed in cases of radiation-induced mucositis, which is associated with the destruction of minor salivary glands in patients with a tumour who undergo radiation therapy in the region of the head and neck. Hyposialia appears in infectious diseases of the oral mucosa, primarily only in acute erythematous candidosis associated with GIT dysmicrobia. It can also manifest in patients in whom the mucosal diseases collide with drug-induced hyposalivation (psychopharmaceuticals, parasympatholytics, non-selective antihistamines, etc.). It is also often present in patients with high fever in systemic acute diseases (where the reduced reflex salivary secretion combines with dehydration). It can be relatively often found in HIV-positive individuals (although it is debatable whether the true cause is a primary disease of salivary glands or drug-induced hyposalivation). Salivary secretion can be reduced to various degrees; due to a major individual variability, we only suspect hyposalivation when subjective complaints are reported by the patient.
Xerostomia (a constant sensation of dryness in the mouth) is a common consequence of hyposalivation. Other consequences of hyposalivation include difficulty chewing and swallowing (especially when eating dry food), sensitivity to spicy foods, unpleasant aftertaste, burning or even pain, pain of salivary glands or difficulty speaking.
In milder forms of hyposalivation, the oral mucosa appears to be clinically normal; in more severe forms, however, objective changes can be observed (i.e., besides the dryness of the mucosa, atrophy and/or erythema can be present, crevices can be found, the tongue is often smooth, dry and wax-like glossy. Lachrymal glands can be also present, with corresponding manifestations of dry keratoconjunctivitis.
There are many reasons (acute and chronic) that can provoke hyposalivation (objective finding) and xerostomia (subjective):
Th.: Causal treatment, otherwise symptomatic therapy. Salivary production can be stimulated by medications (mostly pilokarpine, a parasympathomimetic–acting alkaloid). The effect is however very individual and cardiovascular side effects can occur, it is therefore also necessary to take the general condition of the patient and contraindications into account. Reflex stimulation by sucking sugar-free candies or chewing sugar-free chewing gums, more frequent drinking (without caffeine, alcohol or sugar) can e beneficial. If this does not lead to success, substitution by artificial saliva is necessary (or other means that are on the market now such as moisturizing gels, special mouthwashes, toothpastes, chewing gums or drops).
|Primary (idiopathic, in the narrower sense)
|Secondary (in the broader sense)
The term glossodynia (or stomatodynia) describes unpleasant feelings in the oral cavity for which no objective grounds are usually found. Most commonly, it is burning of the tongue (therefore glossodynia). Stomatodynia is a broader term used in situations when the complaints are associated with multiple regions of the oral cavity. The reasons can be both internal and external – hormonal changes, atherosclerosis, psychogenic influences, neuroanemic syndrome without mucosal changes, etc.
Stomatodynia in a broader sense of the word can also describe conditions where unpleasant feelings in the oral cavity are associated with an objective finding, e.g. stomatodynia in deficiency diseases such as Plummer-Vinson syndrome, Sjögren syndrome, etc.
Stomatodynia in the narrow sense of the word means conditions with no obvious pathological changes in the oral cavity and negative results of general (systemic) examinations. Stomatodynia can occur due to psychogenic influences, hormonal disorders in the menopause, or in atherosclerosis. Most commonly, middle-aged and elderly women between 45 and 70 years of age are affected (under 30 years of age, occurrence of stomatodynia is very rare). It is likely that multiple mechanisms participate in stomatodynia development, including the constitutional predisposition of the organism (rich in sensitive innervation), terrain predisposition (neuropathic or psychoneuropathic terrain), acute predisposition (e.g. menopause) and a triggering mechanism (that can be represented in principle by any painful or unpleasant impulse including a simple dentistry procedure).
Clinical picture: The patient complains about unpleasant sensations in the oral cavity, such as sensation of paresthesia (burning, itching, pain, dryness, aftertaste). The objective finding on the oral mucosa however does not correspond with the described complaints or is completely normal. The tongue is most commonly affected (in approximately 80 % of cases), followed by the palatal mucosa and, less commonly, other regions. The complaints can be of wandering character and their intensity can fluctuate.
Dg.: Establishing diagnosis requires a meticulous taking of the patient’s history (search for a possible cause in systemic diseases), a detailed examination of the oral cavity (examination of the teeth, prosthetic devices, galvanic currents, microbiology), overall examination of the patient (expert opinions from other fields of medicine, including psychiatric and neurological examinations) and lab tests (blood count, biochemistry, plasmatic Fe levels), X-ray of the cervical spine and of the temporomandibular joints. For example, atypical forms of neuralgias of glossopharyngeal nerves may manifest by lingual pain only.
Th.: Glossodynia (and stomatodynia) can be looked upon not just as a disease but as a manifestation that can accompany various afflictions. As a broad range of provoking factors can result in this problem, it is necessary to identify and treat the causal factor (e.g. galvanic irritation) or disease (e.g. pernicious anaemia). If the cause cannot be identified, vitamins, antibiotics, anabolics, physical treatment, sedatives and psychotherapy can all be tried.
|In the mouth
|Nose and maxillary sinuses
(after Kovaľová et al., 2010))
|odour from the mouth is not present
|slight smell of the mouth (sensible only during therapy)
|deep smell of the mouth (sensible upon arrival of the patient to the ambulance up to 1 m distance)
Foetor ex ore, also called mouth odour or halitosis, is defined as intensive odour from the oral cavity. It is therefore a symptom the manifestation of which can be associated with many local, intraoral, causes as well as extraoral factors (pathological changes in the nasopharynx, sinuses, lungs, or smell of food the patient has eaten).
in the mouth
mucosal diseases: ulcerative gingivostomatitis, post-extraction coagulum decay, ulcerative tumours, etc.
diabetes mellitus (acetone odour)
lead intoxication (sweetish metallic)
The bad breath can also follow ingestion of some foods (onion, garlic, alcohol) – the odour has its origin in metabolic products that are, following absorption into the organism from the GIT, excreted from the bloodstream in the lungs.
Th.: Causal, i.e., requiring identification and removal of the cause. Adherence to the rules of the oral hygiene, perfect dental treatment; if diseases are at fault, their treatment. Locally, deodorants or antiseptic means for washing the mouth can be used (hydrogen peroxide, CHX in commercially produced preparations, etc.).