Salivary gland stones are concretions (salivolites) formed in the excretory ducts or parenchyma of the salivary glands (submandibular, parotid, sublingual, small). When the duct is blocked, salivary gland stones cause acute pain (salivary colic), enlargement of the gland, sialadenitis phenomena; in some cases, the formation of an abscess or phlegmon of the salivary gland may occur. The presence of salivary stones is diagnosed by palpation, ultrasound of the salivary glands, sialography, CT, sialoscintigraphy. To remove salivary gland stones, conservative therapy may be prescribed, salivary duct augmentation, lithotripsy, sialendoscopy, open surgery or extirpation of the salivary gland may be performed.
Meaning
Salivary gland stones (sialolithiasis, salivary stone disease) are single or multiple mineral formations that clog the ducts of the salivary glands. Salivary gland stones are found in 1% of the population, mainly at the age of 20-45 years. In dentistry, among the diseases of the salivary glands, sialolithiasis accounts for 20.5-78% of all pathology. In 85-95% of cases, stones are formed in the submandibular salivary glands and the warton duct; in 3-8% – in the parotid glands and the Stensen duct; extremely rarely – in the sublingual and small salivary glands. In about a quarter of cases, there are multiple stones of the salivary glands.
Small stones of the salivary glands are easily washed out by saliva; however, large concretions can clog the lumen of the duct. The mass of salivary gland stones varies from 3-7 to 20-30 g, the value is from several millimeters to several centimeters. In the parenchyma of the salivary glands, stones of a rounded shape are usually formed; in the excretory ducts, they are oblong. Salivary concretions often have a yellowish color, uneven surface, different density.
Causes
The formation of salivary gland stones is facilitated by a combination of general and local factors. Among the first are disorders of calcium metabolism and vitamin A deficiency in the body. Patients with urolithiasis, gout, hyperparathyroidism, hypervitaminosis D, diabetes mellitus are prone to the formation of salivary gland stones. The risk of salivary gland stones increases in smokers, patients taking certain medications (antihistamines, hypotensive, diuretics, psychotropic, etc.).
Local causes include anomalies of the ducts of the salivary glands (narrowing, ectasia, wall defects, etc.) and changes in their secretory function. The presence of stones is always accompanied by inflammation of the salivary glands (sialadenitis), but the question of what is primary – stone formation or infection of the gland remains controversial.
Salivary stone is usually formed around a nucleus having a microbial or non-microbial nature. In the first case, the nucleus is most often a conglomerate of microorganisms (actinomycetes), in the second – an accumulation of exfoliated epithelium and leukocytes, foreign bodies trapped in the duct of the gland (fish bones, fruit seeds, toothbrush bristles). Salivary gland stones consist of components of organic and mineral origin. The organic component (10-30%) includes amino acids, ductal epithelium, mucin; minerals (70-90%) are represented by calcium phosphate and carbonate, sodium, potassium, magnesium, chlorine, iron. In general, the chemical composition of salivary stone is close to tartar.
Most likely, a number of endogenous and exogenous factors are involved in the etiopathogenesis of salivary stone disease, leading to a change in the composition and secretion of saliva, a decrease in the rate of salivation, a shift in pH to the alkaline side and the loss of mineral salts from saliva.
Symptoms
When the stone is localized in the parenchyma of the salivary gland, the course of the disease is asymptomatic. At this stage, concretions are an accidental finding during an X-ray examination of a patient for another odontogenic disease.
Subjective and objective signs of salivary stone disease usually develop when the stone of the salivary gland reaches a relatively large size and blocks the lumen of the excretory canal. In the clinically expressed stage, patients notice bursting sensations and swelling of the salivary gland during meals, an unpleasant taste in the mouth. A characteristic feature of salivary gland stones is the so-called “salivary colic” – an acute pain attack associated with saliva retention and a sharp increase in the size of the gland duct.
When a stone blocks the duct of the submandibular salivary gland, pain occurs when swallowing with irradiation into the ear or temple. In some cases, stones can be seen or felt in the area of the opening of the duct of the salivary gland. Exacerbation of sialadenitis is accompanied by the phenomena of general intoxication – subfebrile body temperature, malaise, headache.
With a complicated course of salivary stone disease, abscesses and phlegmons may form in the area of the affected salivary gland and its ducts. In some cases, there is a perforation of the gland with the release of the concretion into the soft tissues.
Diagnostics
External examination, as a rule, reveals an increase in the size of the corresponding gland; bimanual palpation reveals its dense consistency and soreness. Often the stone can be found when probing the duct of the salivary gland. In some cases, the mouth of the duct gapes, a mucous or purulent secret is secreted from it.
To confirm the presence of stones, an overview radiography and radiopaque examination of the salivary gland (sialography, digital sialoscopy), ultrasound of the salivary glands are performed. In case of difficulties in differential diagnosis, computer sialotomography, sialoscintigraphy is performed. In order to study the secretory function of the salivary glands, sialometry is shown. To study the composition and properties of saliva, biochemical analysis, pH is investigated.
Salivary gland stones must be differentiated from lymphadenitis, oral tumors, phlebolitis, odontogenic abscess, parotid phlegmon.
Treatment
In some cases, stones of the salivary glands can come out spontaneously; sometimes conservative therapy is prescribed to facilitate their discharge: a salivary diet, gland massage, thermal procedures, augmentation of the ducts of the salivary glands. Antibiotics are prescribed for the prevention and relief of acute sialadenitis.
Salivary gland stones located near the mouth of the duct can be extracted by a dentist using tweezers or by squeezing. Surgical tactics involve the removal of stones from the duct of the salivary gland in various ways. The most advanced method of treating salivary stone disease is interventional sialendoscopy, which allows to remove salivary stones endoscopically, eliminate cicatricial strictures of the ducts. Extracorporeal lithotripsy, the crushing of salivary gland stones with ultrasound, is also among the modern minimally invasive methods of treating sialolithiasis. In some cases, intraductal litholysis is effective – the chemical dissolution of stones by injecting a 3% solution of citric acid into the ducts of the salivary gland.
Surgical removal of salivary gland stones can be carried out in an open way – by dissecting the excretory duct from the side of the oral cavity. At the stage of abscessing of the gland, the abscess is opened, the wound edges are diluted to ensure an unhindered outflow of purulent exudate and the discharge of concretion. With recurrent stones or irreversible changes in the salivary gland, radical surgical intervention is indicated – extirpation of the salivary gland.
Prognosis and prevention
Radical removal of salivary glands is accompanied by xerostomia, violation of the microflora of the oral cavity, accelerated destruction of teeth, which, without a doubt, reduces the quality of life of patients. Thanks to the use of modern methods of treatment, in about 80-90% of cases, it is possible to avoid the removal of the salivary gland and limit oneself only to the extraction of the salivary gland stone.
Further prognosis and prevention of salivary stone disease largely depend on the elimination of factors contributing to stone formation: violations of mineral and vitamin metabolism, anomalies of the ducts of the salivary glands, bad habits, correction of drug therapy.
Literature
- Arifa S. P., Christopher P. J., Kumar S., Kengasubbiah S., Shenoy V. Sialolithiasis of the Submandibular Gland: Report of Cases // Cureus, 2019; 11 (3): e4180.link
- Oteri G., Procopio R. M., Cicciù M. Giant Salivary Gland Calculi (GSGC): Report Of Two Cases // Open Dent J, 2011; 5: 90-95. link
- Myneni S. R. Effect of baking soda in dentifrices on plaque removal // J Am Dent Assoc, 2017; 148 (11S): S4-S9. link
- Hammett J. T., Walker C. Sialolithiasis // StatPearls, 2020.