Halitosis is a symptom that emits a special odor when breathing or opening the mouth, and it occurs in middle-aged and elderly people. The human mouth is the common channel of the digestive and respiratory tracts, as an open organ its colonized bacteria species up to more than 400 species, coupled with the oral cavity often mixed food residues, drugs, oral temperature, humidity, PH daily changes in a wide range, its micro-ecological environment is suitable for bacterial growth and reproduction, will greatly increase the number of bacteria, thereby increasing the concentration of breath.
Normal breath should be fresh and slightly sweet, even sometimes with a fragrance similar to the fragrance of a blooming chestnut flower. Halitosis (malodor) can be divided into a broad sense of bad breath and a narrow sense of bad breath. Halitosis in English refers to bad breath from the gastrointestinal tract. There is also a phenomenon called halitophobia, where the patient does not have any objective evidence of halitosis, but is self-conscious of suffering from halitosis, i.e., psychogenic halitosis.
A. Causes of bad breath
Halitosis is caused by anaerobic bacteria lurking on the surface of the teeth and the back of the tongue after decomposing proteins, peptides and amino acids, producing odoriferous, sulfur-containing volatile sulphide compounds (VSCs), two sulfur-containing amino acid components of proteins, namely cystine (cystine) and methionine (methionine) produced after decomposition Sulfur-containing compounds are mainly hydrogen sulphide (hydrogen sulphide) and methyl mercaptan (methyl merecaptan).
Next is dimethyl sulphide (demethyl sulphide) and dimethyl disulphide (dimethyl disulphide), the first three have been shown to contain the active role of sulfhydryl (-SH), at low concentrations can emit a strong odor, while dimethyl disulphide does not have sulfhydryl group and the production of halitosis is basically irrelevant. In addition, there are some organic acids also associated with bad breath, such as butyric acid (butyric) and propionic acid (propionic), as well as compounds like indole (indole), methylindole (skatole) and cadaverine (cadaverine), the amount of which is generally unrelated to VSCs.
There are at least 82 microorganisms in the oral cavity that are capable of producing hydrogen sulfide, methyl mercaptan and fatty acids during metabolism. These bacteria are mainly Clostridium (Fusobacterium), Haemophilus (Haemophilus), Veillonella (Veillonella) and Treponema denticola (Tooth scum dense spirochetes). Together with the presence of tongue papillae, which greatly increases the surface area of the tongue, the tongue surface has a large number of shed epithelial cell debris, food debris, dead white blood cells and bacteria; subgingival plaque and tooth adjacent plaque with rough surface are ideal hiding places for anaerobic bacteria.
The activity of bacteria is partly influenced by immunoglobulins. IgA in saliva is able to inhibit bacterial activity. Therefore, the increase of anaerobic bacteria on the lingual and dental surfaces may be related to IgA deficiency. About 0.1% of the population suffers from congenital IgA deficiency. In addition to genetic factors, there are acquired IgA deficiency disorders, and these patients are prone to respiratory infections, allergies, arthritis, and a variety of autoimmune diseases. In a survey of 155 immunodeficient patients at the University of Toronto, 137 were found to have significant halitosis. The diseases most closely associated with bad breath are caries, periodontal disease and oral cancer.
Some studies have reported that the severity of these diseases is directly proportional to the severity of bad breath. In addition to oral diseases, diseases of organs near the mouth, such as tonsillitis, sinusitis, nasal polyps, and respiratory foreign bodies, are also relatively common causes of bad breath. Many systemic diseases that are not well controlled, the patient’s exhaled breath will have a distinct idiosyncrasy with certain specific flavors.
For example, the breath of diabetic patients with a fruity taste, the breath of patients with renal failure with a fishy smell, liver cirrhosis patients with a strong sulfur smell in the mouth, lung abscess or bronchial dilatation patients often have a ****ty malodor. However, the etiology of bad breath goes far beyond these diseases. Materials containing clove oil and pomegranate oil are commonly used in oral therapy, and they produce an unpleasant odor as they decompose in the mouth, and are considered bad breath. Reduced saliva production during sleep, when the tongue and cheek muscles are largely at rest, also tends to cause bad breath.
It has also been found that dietary habits play an important role in the formation of bad breath. Foods such as onions, garlic, and animal fats can cause specific bad breath. This bad breath cannot even be removed by brushing the teeth. Some patients develop bad breath after taking certain medications, such as dimethyl sulfide, quinine, and antihistamines. However, these halitosis are transient and related to food or drugs, so they are easier to identify. Psychological halitosis is the patient’s self-perception of bad breath that does not actually exist. Such patients have obvious psychological factors manifested.
Its treatment is relatively difficult. There is a common misconception that gastrointestinal disorders are also an important cause of halitosis. In fact, the esophagus is closed when not eating. It is only when burping that gas from the gastrointestinal tract is expelled through the mouth. Therefore, the bad breath that can often be felt has little to do with the gastrointestinal tract. However, there are some more serious gastric diseases, such as gastric cancer, malabsorption syndrome, reflux esophagitis, etc., coupled with esophageal closure malpractice, often accompanied by persistent bad breath.
Second, the classification of halitosis
Halitosis can be divided into non-pathological halitosis and pathological halitosis. Non-pathological halitosis is usually produced in the normal physiological process, generally for a short period of time, such as hunger, consumption of certain drugs or onions, garlic and other irritating foods, smoking, sleep due to reduced saliva secretion of a large number of bacteria decomposition of food residues may cause a short period of bad breath. Pathological halitosis is mostly caused by local or systemic diseases, and can be divided into orogenic halitosis and non-oral halitosis according to its source.
There is another type of halitosis belongs to the mental halitosis, which can be regarded as olfactory implication syndrome, which is related to psychological and mental factors, halitosis and human emotions. Those who are easily agitated, angry or depressed are more prone to halitosis. Hormonal changes, such as menstruation, pregnancy, etc., are also more likely to occur bad breath. It is not repeated here.
(1) Non-oral halitosis Non-oral halitosis is caused by suffering from systemic diseases or various infections, mainly including: respiratory diseases (infection and necrosis of the nasal cavity, maxillary sinus, pharynx, lung), digestive system diseases (gastritis, gastric ulcer, duodenal ulcer, gastrointestinal metabolic disorders, constipation, etc.), substantial organ damage (liver failure, kidney failure) and diabetic ketosis, uremia, leukemia, vitamin deficiency, heavy metal poisoning and other diseases caused by halitosis.
(2) orogenic halitosis According to statistics, 80% to 90% of halitosis is from the oral cavity. There are untreated dental caries, residual roots, residual crowns, bad restorations, abnormal structures, gingivitis, periodontitis and oral mucosal disease in the oral cavity can cause bad breath. In patients without these problems, their bad breath may be caused by increased and thickened plaque on the back of the tongue due to poor oral habits and oral hygiene. In some cases, if the patient suffers from diseases that reduce saliva production, such as SjÖrrgen’s syndrome, after radiation therapy for tumors, etc. may also form bad breath.
Third, the diagnosis and differential diagnosis of halitosis
A substance must exist in the form of a gas and reach the receptors in the upper part of the nose to be able to be smelled. Before there were scientific instruments to monitor bad breath, detecting and diagnosing bad breath was basically a subjective practice. People’s judgment of bad breath is often disturbed by their health, fatigue and mood. The degree of sensitivity and experience of each person also affects their identification and judgment of bad breath to varying degrees. Also, there is a certain degree of discrimination and rejection of another person’s oral odor by a certain ethnic group.
In daily life, the judgment of bad breath, there are the following methods.
1, feedback from people who live in close contact: the human brain has a special ability to almost completely inhibit its own odor. The reason for this is unclear, and it may be related to the self-protective function that gradually developed during the long-term evolution of animals. People in close contact with the patient can know the good time of halitosis, triggering factors and aggravating factors.
2.Spoon test method: Use a spoon to scrape the plaque and residue from the back of the tongue, and sniff it by yourself or others.
3, home microbiological testing: This method was invented by Mitchell M. Strumpf. The specific method is to ask the patient to take several deep breaths to make the tongue surface as dry as possible, then use two sterilized cotton swabs to rotate with pressure at the midline of the back of the patient’s tongue to collect as much coverage of the tongue surface as possible. The tester inserts the swabs into the bottom of two test tubes containing a special substrate, seals them immediately, and starts counting the time.
If a yellowish-brown color with colored spots appears at the swab insertion in less than 30 minutes, it indicates that bad breath is likely; if the above phenomenon occurs in 30 to 90 minutes, it indicates that the patient occasionally has bad breath; if more than 90 minutes, it indicates that bad breath rarely occurs. Do not eat or drink for at least 4 hours before doing this test. 4. Wrist lick test: this practice is to let the patient spit some saliva at the wrist and lick it dry, and then the tester sniff the area after the saliva evaporates. The reliability of this method is not high.
The following detection methods are often used in the clinic.
1, halitosis judge detection method: that is, experienced oral surgeons play the role of “judge” to directly examine the patient and make a diagnosis. This method can be called the gold standard in the diagnosis of halitosis.
2, microbial and fungal detection methods: including bacterial culture methods, DNA or RNA probe method for detecting microorganisms associated with halitosis, and cell smear detection method for diagnosing candidiasis. These methods need to be further improved, because their results still lack specificity and consistency.
There is also a BANA assay which detects Mycobacterium tuberculosis, Streptococcus caries haemolyticus, Streptococcus forsythiae haemolyticus, and carbon dioxide phagocytosis. All of these bacteria produce trypsin-like enzymes, which hydrolyze synthetic peptides (BANA). The disadvantage of these methods is that they cannot be quantified and it is difficult to determine the cause of bad breath. In general, these methods are more suitable for targeted treatment of persistent halitosis.
3, saliva culture test: first ask the patient to spit out 1-2ml of saliva into an empty petri dish, immediately cover the lid and put it into a 37 ℃ incubator for 5 minutes. Then give the petri dish to the “judge” and smell the odor at a place 4cm away from the nose. This is similar to the wrist lick detection method, simple and easy, but not accurate enough.
4, volatile sulfide detection method: currently on the market only one such instrument. Moreover, its sensitivity is not high and specificity is not strong.
5, artificial nose: the method of computer analysis is used to identify bad breath. It can distinguish whether the odor exhaled by the patient is from food, drugs, cosmetics or other substances. Now there are more instruments used Abiodent Halimeter system, it can distinguish and quantitative detection of the patient’s exhaled gas, but also need to combine special sensory determination and bacteriological testing, it takes a longer time to get the results. Moreover, the instrumentation of this system requires considerable investment, which makes it difficult to be widely used in clinical practice.
The portable sulfide monitor (Halimeter) is simpler, cheaper, and can produce more objective results in a short time, so it is widely used. However, it is less sensitive to methyl mercaptan than to hydrogen sulfide. Periotemp, on the other hand, provides objective data by measuring the temperature of periodontal pockets to assist in the diagnosis of halitosis. In addition, the BANA test, modified Oratest, can be used as an auxiliary method to diagnose halitosis. Most physicians currently use a subjective approach to the diagnosis of halitosis.
As mentioned above, this method is interfered by many factors. However, in non-teaching and research units, this method is still not a stopgap measure. In this case, it is not difficult to diagnose halitosis, the difficult part is to determine the exact source of halitosis. As the name implies, bad breath is the gas from the mouth with odor. So you must first determine whether this gas comes from the oral cavity or the nasal cavity. Let the patient alternate between open-mouth exhalation and closed-mouth exhalation, it will not be difficult to make a judgment. Bad breath also has the characteristic of becoming more and more pronounced with the duration of the conversation. However, after rinsing and cleaning the mouth, the bad breath will improve.
When making a diagnosis of bad breath, a specific time should be arranged for the patient, and the patient should be asked to refrain from eating, drinking, rinsing, smoking, chewing gum and other things for at least two hours before this time, and not to use perfume, lipstick and other cosmetics that may affect the diagnosis. If the patient is taking antimicrobials, they should also be stopped two days before the visit. To make the diagnosis more accurate, it is best to have the person who has the most contact with the patient (e.g. husband or wife) with you to provide more detailed and objective information.
After a clear diagnosis of halitosis is made, the source of the bad breath must be identified. In the oral cavity, the common sites of halitosis are the dorsum of the tongue (especially the root of the tongue), the subgingival area, the adjacent surfaces of the teeth, poor restorations (e.g., overhangs, crown edges), food inclusions, apical abscesses, and removable dentures.
Halitosis from the mouth and tongue has the following characteristics.
1, let the patient pinch the nose and exhale, you can still smell the odor.
2.The back third of the tongue has a relatively thick tongue moss, and bad breath disappears after complete removal of the tongue moss.
3.There is food residue under or around the filling or restoration, and the bad breath disappears after removal.
4, there are ulcers in the mouth, mucosal ulcerative stomatitis, bad breath is reduced and disappears with the improvement and healing of ulcers.
5.The depth of periodontal pocket is more than 4 mm, there is gingival margin inflammation with bleeding or pus overflow.
6. Loose fillings, cavities, alveolar abscesses, calculus, poor restorations, interdental food impaction. 7. The patient is taking antibacterial agent for a long time may induce fungal infection.
8. Patient suffering from dry mouth syndrome may be accompanied by oral flora dysbiosis.
9. Tonsils are infected and enlarged.
Sometimes, odors from sinusitis, nasal polyps, nasal foreign bodies, congenital developmental abnormalities (such as cleft palate), tonsil stones and other diseases are also easily confused with halitosis and need to be carefully searched for and ruled out one by one. Halitosis arising from the nasal and upper respiratory regions is caused by the local accumulation of mucus that is not discharged in time during sleep. In the waking state, mucus then accumulates mainly in the posterior nasal cavity.
Allergic patients with significant cata symptoms are often not prone to halitosis, but the incidence of halitosis is greatly increased at night when the secretion is reduced or when there is a co-infection. The halitosis of such patients is particularly pronounced in the morning and is significantly reduced an hour after waking up. This is why some people call it “early morning halitosis”.
Halitosis from the nasal cavity, nasopharynx, sinuses and oropharynx have the following characteristics.
1. Bad breath occurs mainly in the morning, and the back of the tongue has no obvious tongue coating.
2. The patient has an increased body temperature and enlarged peri-pharyngeal lymph nodes.
3. The patient has allergies, self-conscious discharge from the posterior part of the nose, and bad breath occurs mainly in the morning. 4. There is a history of chronic sinusitis and recent symptoms of sinusitis.
5. After excluding the causative factors of the oral cavity, there is no significant improvement in the symptoms of halitosis.
This type of bad breath is easy to coexist with bad breath caused by oral factors, because of poor local ventilation, increased secretions, bacteria are easy to breed. And oral hygiene can be improved to significantly reduce bad breath. If the bad breath is not eliminated or significantly improved after excluding the oral and nasal causes, the patient must consider whether there are digestive tract diseases, systemic diseases such as bronchitis, lung inflammation, renal failure, malignant tumors, metabolic diseases, and biochemical factor disorders.