Oral Candidiasis-II

What is oral thrush?

Thrush is an infection caused by a yeast germ called Candida spp. The mouth is a common site whereCandida spp. causes infection. Candidal infection in the mouth is called oral thrush. 

Who gets oral thrush?

Small numbers of Candida spp. commonly live on healthy skin and in a healthy mouth. They are usually harmless. Healthy people do not normally get oral thrush. However, certain situations or conditions may cause an overgrowth of Candida spp. which can lead to a bout of oral thrush. These include:

• Being a baby. Oral thrush is quite common in young babies.
• Wearing dentures, especially if they are not taken out at night, not kept clean, or do not fit well and rub on the gums.
• A course of antibiotics. Antibiotics will kill harmless bacteria which live in the mouth. They do not kill Candida spp. which may multiply more easily if there are fewer bacteria around.
• Excessive use of antibacterial mouthwash (for similar reasons to above).
• Taking steroid tablets or inhalers.
• Having a dry mouth due to a lack of saliva. This may occur as a side-effect from certain drugs (such as antidepressants, antipsychotics, chemotherapy), following radiotherapy to the head or neck, or as a symptom of Sjögren's syndrome.
• Having diabetes.
• Having severe anaemia.
• Lacking iron, folate or vitamin B12.
• Having a poor immune system. For example, if you are taking medicines that suppress your immune system, if you have certain cancers, or if you have HIV/AIDS.
• Being frail or in generally poor health.
• Smoking. Smokers are more likely to develop oral thrush.

Oral thrush is not contagious. You cannot pass on oral thrush to other people.

What are the symptoms of oral thrush?

• The classical symptom is white spots that develop in your mouth. The spots may join together to form larger spots called plaques. They may become yellow or grey. If you wipe off a spot, the underlying tissue may be red but it is not usually sore or painful.
• Often there are no white spots. Areas in your mouth may just become red and sore. This more typically occurs if you get thrush after taking antibiotics or steroids.
• Denture wearers may develop an area of persistent redness under a denture.
• You may develop sore, cracked, red areas just outside your mouth. This mainly affects the angle where the upper and lower lips meet (angular stomatitis).
• Some mild oral thrush infections are painless. However, sometimes oral thrush is quite sore and can make eating and drinking uncomfortable. Some babies with oral thrush may drool saliva, or not be able to feed properly because of soreness.
• Taste can be affected in some people with oral thrush.

How is oral thrush diagnosed?

Doctor will usually diagnose oral thrush by typical symptoms and the typical appearance in mouth. No investigations are usually needed to diagnose oral thrush.

However,doctor may sometimes suggest a blood test to look for certain conditions that may make you more likely to develop oral thrush. For example, a blood test to see if you are lacking iron, B12 or folate.

If oral thrush does not respond to treatment (see below), your doctor may suggest that they take a swab from inside your mouth. The swab is then sent to the laboratory to be examined under a microscope. They can also try to grow the Candida spp. in the laboratory.

Occasionally, a biopsy is needed to confirm a diagnosis of oral thrush. A small sample is taken from the white patches inside your mouth and this can be examined under a microscope.

What is the treatment for oral thrush?

Locally applied treatment

For mild oral thrush, the usual treatment that is tried first is miconazole mouth gel for seven days. Sometimes a two-week course is needed. Nystatin drops are another option if miconazole gel cannot be used (for example, if you are known to be allergic to it). 

Follow the instructions in the packet. Basically:

• The gel or drops should be used after you have eaten or drunk.
• Smear a small amount of gel on to the affected areas, with a clean finger, four times a day.
• With the drops, you use a dropper to place the liquid inside your mouth on to the affected areas four times a day.
• Ideally, you should not eat or drink for about 30 minutes after using either the gel or the drops. This helps to prevent the drug from being washed out of your mouth too soon.

Anti-thrush tablets

Tablets that contain a drug called fluconazole can also help to clear fungal and thrush infections from the body. Tablets tend to be used in more severe or serious cases. For example, for people with a poor immune system who develop extensive oral thrush. Tablets are usually prescribed for seven days and this will usually clear oral thrush.

Adjustment of other medication

If you are taking other medication that may have caused oral thrush, such as steroids or antibiotics, your doctor may need to change this medication or reduce the dose to help clear up your thrush.

Other drugs such as itraconazole, ketoconazole or amphotericin can also be used if above drug regime doesn't succeed.

Can oral thrush be prevented?

It may be possible to alter one or more of the situations mentioned above to help prevent further bouts of oral thrush. For example:

• If you have diabetes - good control of your blood sugar level reduces the risk of thrush and other infections.
• If you use steroid inhalers - having a good inhaler technique and using a spacer device may reduce the risk of thrush. Also, rinse your mouth after using the inhaler, to help remove any drug particles left in your mouth. Ask your doctor about reducing your dose of steroid in your inhaler to the lowest level needed to control your asthma.
• If you wear dentures:
  • Leave your dentures out overnight, or for at least six hours daily. Constant wearing of dentures, and not taking them out at night, is thought to be one of the most common causes of oral thrush.
  • Clean and disinfect dentures daily. To clean, use soapy water and scrub the dentures with a soft nailbrush on the fitting surface - that is, the non-polished side. Then soak them in a disinfecting solution. The type of solution and the time they should be soaked for will be advised by your dentist. Rinse the dentures after disinfecting them, and then allow the dentures to air dry before wearing them again. Drying like this helps to kill any Candida spp. that might be stuck to the dentures.
  • Clean the inside of your mouth (where the dentures sit) with a soft brush.
  • See a dentist if the dentures do not fit well.
• If you take medication which causes a dry mouth - take frequent sips of water. (See separate leaflet called 'Dry Mouth' for more details.)
• If you are found to have anaemia or low levels of vitamin B12, folate or iron, treating this may help to prevent oral thrush in the future.
• If you are a smoker, quitting smoking may help to prevent further bouts of oral thrush.
• Certain groups of people may be given anti-thrush tablets to help to prevent oral thrush. For example, people who are on medication to suppress their immune system or who are receiving chemotherapy for cancer.

ORAL CANDIDIASIS (MONILIASIS, THRUSH)-I

Candida albicans is the most frequent cause of fungal human disease in general and very much the most common cause of oral fungal involvement. The organism is a normal inhabitant of the oral cavity in 30 to 40% of the population. When the bacterial flora of the oral cavity is disturbed by antibiotic therapy, or in individuals who have diabetes mellitus, xerostomia (dry-mouth), weakened immunity (for example, AIDS), or severe debilitation, this otherwise harmless microorganism multiplies to cause overt lesions.

The causes and the course the disease:

Oral Candidiasis takes the form of a superficial, curdy, gray to white membrane that can be readily scraped off to reveal an underlying erythematous inflammatory base. In the milder expressions, there is minimal ulceration of the mucosal surface and only a superficial subepithelial inflammatory infiltrate. More severe oral infections may produce mucosal ulceration and a correspondingly greater inflammatory reaction.

In the debilitated, compromised host, the oral candidal infection may be spread into the esophagus by the introduction of a nasogastric tube. Even more threatening, in the vulnerable individual, is more widespread mucous-membrane infection with invasion of the fungi into the deeper tissues of the oral cavity, increasing the potential for bloodstream diffusion. Uncommonly, and in the vulnerable individual, oral candidiasis is followed by widespread mucous membrane infection that has greater potential for invasion and distribution.

The clinical features:

The patient with candidiasis may complain of a burning sensation, tenderness, or sometimes pain around the affected mucosa. Spicy foods will cause occasional discomfort because of the increased sensitivity of the affected mucosa. These infections were more common in women and in patients over 40 years old. Fifty percent of the patients came to them with a chief complaint of oral burning. The patient may report having been on a prolonged course of broad-spectrum antibiotics for a sore throat or other infection.

About oral candidiasis, four major types are recognized: (1) pseudomembranous; (2) hyperplastic; (3) erythematous (atrophic); and (4) angular cheilitis.

The pseudomembranous oral infection may show as fine whitish deposits on an ervthematous patch of mucosa or as more highly developed small, soft, white, slightly raised plaques that closely resemble to milk curds. The disease may range in severity from a single region to a diffuse whitish involvement of several or all the mucosal surfaces. The mucosa next to, or between, these whitish plaques appears red and moderately swollen. The plaques or pseudomembranes may be stripped off the mucosa, leaving a raw bleeding surface. When separate restricted sites are involved, the cheek mucosa and vestibule are the most frequent regions affected—followed by the dorsum of the tongue, palate, gum, floor of the mouth, and lips.

The hyperplastic type is characterized by white plaques which cannot be removed by scraping. The most common location is the cheek mucosa. In patients infected with HIV, the hyperplastic candidiasis most often is found in the lip commissures.

The erythematous (atrophic) type is characterized by a red appearance. The color intensity may vary from fiery red to a hardly distinct pink spot. Common locations are the palate and dorsum of the tongue, as in the so-called multifocal candidiasis in patients who are not infected with HIV but who are heavy smokers. However, erythematous candidiasis may also appear as spotty areas of the cheek mucosa. This is a characteristic feature of the HIV infection, but is often overlooked.

Angular cheilitis is characterized by cracks radiating from the angles of the mouth, often associated with small white plaques.  In the elderly, this is not an unusual lesion and may be because of anemia, loss of chewing vertical dimension, or vitamin deficiency. But it should be remembered that when it is noted in a young man, it could be the first sign of an HIV infection. Today it is recognized the most important etiologic cause is Candida albicans. However, Staphylococcus aureus may also be present in some patients.

The differential diagnosis:

The diagnosis of candidiasis relies on the clinical features and the presence of Candida hyphae on smears examined by potassium hydroxide, periodic acid-Schiff or Gram stain.

As a rule all the keratotic lesions may be readily ruled out from consideration, since they cannot be easily removed by scraping. Necrotic white lesions that must be considered in the differential diagnosis are chemical burns, gangrenous stomatitis, superficial bacterial infections, traumatic ulcers, necrotic ulcers of systemic disease, and the mucous patch.

The mucous patch of syphilis is usually a discrete, small, white necrotic lesion on the tongue, palate, or lips, whereas candidiasis is usually much more diffuse. The accompanying skin lesions of secondary syphilis and the positive serologic findings readily distinguish the mucous patch from candidiasis.

Necrotic ulcers and gangrenous stomatitis of debilitating systemic disease may be difficult to differentiate from candidiasis because the latter entity is usually also found in patients with undermining secondary disease. As a general rule, if the ulcer is deep then candidiasis would not be the primary cause. Traumatic ulcers with necrotic surfaces can often be related to a history of specific trauma. Chemical burns sometimes closely mimic candidiasis. The distinction is usually made by an accurate history, disclosing that a medicament has been applied to the mucosa.

Superficial bacterial infections may occur in patients with debilitating disease and indeed may mimic pseudomembranous candidiasis. Culture of these lesions yielded generous bacteria such as staphylococci, Neisseria, coliform bacteria, and lactobacilli.

The recommended treatment:

The management of patients with oral candidiasis is twofold: (1) to identify, correct, or eliminate predisposing or precipitating causes and (2) to provide antifungal therapy.

The underlying systemic conditions (such as diabetes, malnutrition, and anemia) and the discontinuation of broad-spectrum antibiotics are recommended for the first approaches. Local resistance can be improved by good oral hygiene and by leaving dentures out as much as possible.

The six drugs that are chiefly used for antifungal therapy are gentian violet, nvstatin, amphotericin B, miconazole, clotrimazole, and ketoconazole. Nystatin and amphotericin have been the standard drugs used for oral candidal infections for the last 35 years. Each of these drugs is absorbed poorly from the gastrointestinal tract but is excellent for topical use on mucous membrane and skin lesions.  Most dentists and physicians stress the importance of continuing antifungal therapy at least 2 weeks following disappearance of signs and symptoms of oral lesions.

ANTIBIOTIC PROPHYLAXIS IN DENTISTRY: A REVIEW AND PRACTICE RECOMMENDATIONS

Background. The American Heart Association, or AHA, and the American Dental Association recently changed their recommended protocols for antibiotic prophylaxis against bacterial endocarditis. A new recommendation also has been issued by the ADA and the American Academy of Orthopaedic Surgeons, or AAOS, against routine antibiotic prophylaxis in patients with prosthetic joint replacements. These changes reflect increasing scientific evidence and professional experience in opposition to widespread use of antibiotic prophylaxis in these specific situations and others faced in dentistry.

Results. There are relatively few situations in which antibiotic prophylaxis is indicated. Aside from the clearly defined instances of endocarditis and late prosthetic joint infections, there is no consensus among experts on the need for prophylaxis. There is wide variation in recommended protocols, but little scientific basis for the recommendations. The emerging trend seems to be to avoid the prophylactic use of antibiotics in conjunction with dental treatment unless there is a clear indication.

Conclusions. Aside from the specific situations described, there is little or no scientific basis for the use of antibiotic prophylaxis in dentistry. The risk of inappropriate use of antibiotics and widespread antibiotic resistance appear to be far more important than any possible perceived benefit.

Clinical Implications. Dentists are wise to use antibiotic prophylaxis in only those specific situations in which there is a valid scientific basis for it. Whenever possible, dentists should follow the standard protocols recommended by the ADA, AHA or AAOS.

There is often confusion and misinformation concerning the indications and scientific basis for the use of antibiotics in conjunction with dental procedures. In this review article, we highlight specific situations that warrant the use of antibiotic prophylaxis in the dental setting and briefly discuss the rationale behind current recommendations.

The empiric use of antibiotic prophylaxis for dental procedures, especially those that cause bleeding in the mouth, has become a reasonably well-established practice among dental professionals. However, many dentists are confused by the indications for, and the nature of, antibiotic prophylaxis. They often rely on recommendations from practitioners who quote anecdotal evidence or decide that, when in doubt, the wise and conservative course is to use antibiotic prophylaxis. Furthermore, dentists may consult with a patient’s physician and receive a recommendation for the use of antibiotics in widely varying protocols and combinations. This presents a dilemma for the dentist because he or she may feel obligated to use antibiotic prophylaxis in inappropriate or unnecessary scenarios.

There is a long-held belief in the theory of focal infection such that subclinical infectious foci in the oral region, particularly endodontically treated teeth, result in systemic illness or cause disease processes in distant locations.Although generally regarded as not having scientific merit, this concept often drives recommendations for the use of antibiotic prophylaxis. As a result, dentists and physicians tend to use antibiotics in situations in which there are no clear scientific bases.

The correlation between bacterial infection and endocarditis was described before the turn of the 20th century. It was not until the 1920s, however, that the causal relationship between bacteremia, surgical procedures and infective endocarditis, or IE, was proposed. Lewis and Granthypothesized that surgical procedures provided microorganisms with access to the systemic circulation, which ultimately would result in endocarditis. The specific pathophysiology of IE was not yet identified. Researchers subsequently showed that IE arises from the colonization of a preexisting lesion, usually composed of fibrin and platelets, which develops from the disruption of the endothelial lining via abnormal development, disease or presence of foreign bodies and turbulent blood flow.^2,4

Since the 1930s and 1940s, when studies indicated a significant correlation among dental procedures that cause bleeding, bacteremia and the development of IE, the use of antibiotics has been standard practice for patients identified as being at risk of developing endocarditis. This practice has expanded to include patients at risk of developing infections around prosthetic joints and those with depressed immune systems.In addition, many medical and dental practitioners use antibiotics in conjunction with surgical procedures for otherwise healthy patients in the belief that such therapy will reduce the incidence of perioperative infections.

Clinicians and researchers are increasingly concerned about the overuse of antibiotics and the resulting development of resistant strains of microorganisms.Although the use of prophylactic antibiotics in dentistry is not a major contributing factor to the problem of overuse, the current situation clearly requires judicious and prudent consideration before antibiotic therapy is administered. 

CLINICIAL SITUATIONS CONSIDERED FOR ANTIBIOTIC PROPHYLAXIS

Infective endocarditis. IE, also known as acute or subacute bacterial endocarditis, is defined as an exudative and proliferative inflammatory alteration of the endocardium; it is characterized by vegetations on the surface or within the endocardium that are caused by an infection with microorganisms. A heart valve is commonly involved and proliferation also may occur in the inner lining of the cardiac chambers.^8,9 It is well-recognized that IE arises from the colonization of a preexisting lesion, usually composed of fibrin and platelets, that develops from the disruption of the endothelial lining via abnormal development, disease or presence of foreign bodies and turbulent blood flow. This accumulation of fibrin, blood products and platelets, known as nonbacterial thrombotic endocarditis, or NBTE, adheres to the damaged endothelium. The endothelium is later colonized by bacteria, which, in turn, stimulates further platelet aggregation and the bacteria become incorporated into the vegetations of the lesion.

Congenital or acquired cardiac defects and abnormalities may predispose the heart to endothelial damage and formation of NBTE. Researchers have suggested that these conditions may alter the hemodynamics of the heart, causing turbulence, which, in some way, increases the exposure of predisposed cardiac endothelium to bacterial infection (usually streptococcal).

The current AHA recommendations for the prevention of IE are significantly changed in respect to patients with various cardiac conditions. In general, the trend has been to more specifically describe those conditions that pose significant risk for patients and to delineate low- or negligible-risk situations. As a result, antibiotic prophylaxis is now recommended for fewer conditions. These changes also reflect improvements in the understanding of these disease processes and changing attitudes toward the use of antibiotics. The most notable among these changes include reducing the oral dose of amoxicillin from 3 grams to 2 g, recommending that a follow-up dose of antibiotic be discontinued, and replacing erythromycin with other antibiotics as alternatives to the penicillins. Dajani and colleagues have reported that 2 g of amoxicillin provides several hours of antibiotic coverage. Table 1 shows the new recommendations for prophylactic coverage for certain dental procedures.

Patients with mitral valve prolapse, or MVP, may be at risk of developing tachycardia, syncope, congestive heart failure and endocarditis. The risk of infection, however, is variable and depends on age and severity of the MVP.The decision whether to administer antibiotic prophylaxis is based on the results of echocardiographic tests for regurgitation. The AHA recommmends that patients diagnosed as having MVP with regurgitation receive antibiotic prophylaxis before undergoing dental procedures, but patients with MVP alone (without regurgitation) do not require antibiotic coverage. The risk of developing IE remains greater in patients with prosthetic heart valves and/or a history of endocarditis than in patients with MVP.The current American Heart Association recommendations for the prevention of infective endocarditis are significantly changed in respect to patients with various cardiac conditions.Patients often indicate on a health history form the existence of a heart murmur at some time without having any further knowledge of the nature or extent of the cardiac defect. Because of concerns about the overuse of antibiotics, it is prudent for the dentist to ask for medical evaluation before continuing dental care, rather than to simply prescribe antibiotic prophylaxis when in doubt. Similarly, if a dentist is treating a patient with MVP, it may be reasonable to contact the patient’s physician to determine the specific cardiac anomaly before making a decision about antibiotic prophylaxis.

Patients with prosthetic joints. Prosthetic joint replacement is becoming increasingly common, especially in developed countries with an aging population.  Infections of the prosthetic joints may be classified as early- and late-onset.

Early prosthetic joint infection is presumed to occur after microbial contamination of the surgical site during placement of the prosthesis. Late prosthetic joint infection, or LPJI, typically occurs three or more months after surgery and may involve delayed infection from microorganisms introduced at the time of surgery or via hematogenous spread from a distant site, such as the mouth. With devastating morbidity and a mortality rate of 18 percent, orthopedic surgeons are justified in their concerns about LPJI. The incidence of LPJI associated with dental procedures is extemely low. In a review of 2,693 patient records, Jacobson and Matthews found only one instance (0.04 percent) of LPJI that could be even temporally related to dental treatment.

Routine antibiotic prophylaxis for all patients with prosthetic joints is very expensive ($480,000 to prevent one case of LPJI in 1990). Studies of relative risks show that the risk of death caused by anaphylaxis, especially from the penicillins, far outweighed the risks of developing LPJI. These factors have moved the current consensus toward discontinuing routine use of antibiotic prophylaxis. In their advisory statement, the AAOS and the ADA have recommended the use of prophylactic antibiotics only for patients with total joint replacements (not for patients with only pins, screws and/or plates) and compromised immune systems, Type 1 diabetes mellitus, recent (within two years) joint replacement, previous prosthetic joint infections, malnourishment or hemophilia.

Dentists still may be faced with the situation in which a physician has recommended antibiotic prophylaxis for a patient that the dentist feels is inappropriate. In such cases, the dentist may choose to consult with the patient’s physician in an attempt to alter that recommendation. In any case, the dental practitioner is responsible for assessing each patient’s situation and deciding whether antibiotic coverage would benefit the patient.

PREVENTION OF LOCAL INFECTION IN SURGICAL OR OPERATIVE SITES IN THE MOUTH

Surgical procedures in the mouth generally fall into the clean-contaminated category of surgical classification (that is, native organisms are present); this includes routine exodontics, third-molar surgery and orthognathic surgery.The incidence of infection after dentoalveolar surgery is very low; for third-molar surgery performed by oral and maxillofacial surgeons, the infection rate is approximately 1 percent. Unless the immune system is compromised, antibiotics are not indicated in these cases. For periodontal surgery in which the surgical site is often highly contaminated with microorganisms, antibiotics are usually indicated for most patients with compromised immune systems, for patients at risk of developing IE and for patients with prosthetic joints, especially in the presence of obvious periodontal infections.

The periodontal literature suggests that localized juvenile periodontitis and other forms of early-onset periodontitis may warrant antibiotic coverage, but there is little evidence to support this view. The American Academy of Periodontology recommends that patients with medical conditions that predispose them to periodontal disease also be considered for antibiotic coverage. The use of antibiotic prophylaxis during placement of dental implants is controversial. Preoperative antibiotics appear to decrease the rate of implant failure, but studies have emphasized the prevention of implant failure rather than prevention of the infection itself.

PREVENTION OF GENERALIZED SPREAD OF INFECTIONS IN PATIENTS WITH COMPROMISED IMMUNE SYSTEMS

Patients with compromised immune systems represent a special category for dentists. Because of their illness and/or the treatment rendered for their specific condition, these patients are at higher risk of developing bacteremias, which, in the absence of an adequate host immune system, may rapidly progress to an overwhelming septicemia.

Patients undergoing chemotherapy are particularly susceptible to systemic infections because their immunosuppressed state is caused by their medications. Not only are these patients at higher risk of developing an infection, but the spread and severity of the infection can potentially be rapid and life-threatening. For these patients, we do not recommend antibiotic coverage for routine dental procedures, but it should be considered for invasive procedures such as dental extractions, deep periodontal scaling and other procedures that cause significant bleeding and seeding of bacteria into the systemic circulation.

Patients with human immunodeficiency virus and AIDS, in the absence of bacterial infection, do not generally require antibiotic prophylaxis. However, a clinical judgment should be made when a bacteremia is likely to occur, such as in cases of extraction of teeth with abscesses. Practitioners should consider the use of antibiotics in these patients because of the higher risk of overwhelming systemic infection and an inability to defend against microbial insult because of a depressed immune system.

The final group in this category of patients with compromised immune systems is the population with diabetes. Diabetics, especially those who are insulin-dependent, have a higher rate of systemic disease and often exhibit some degree of leukocyte dysfunction, which may contribute to higher incidences of infection. Insulin-dependent diabetic patients, particularly those with poorly controlled disease, are vulnerable to infections. Therefore, antibiotic coverage for invasive dental procedures is recommended in patients with poorly controlled or uncontrolled diabetes, but is generally not required for those in whom the disease is well-controlled or for those who are not dependent on insulin therapy.

There is some ongoing debate among clinicians and authors over the use of antibiotic coverage for chronic intravenous drug abusers and for patients who have undergone splenectomy. The incidence of IE among chronic intravenous drug abusers is several times higher than that seen in the healthy population. Although there is no clear-cut evidence that antibiotics are effective in cases of native valve endocarditis, antibiotic coverage may be warranted until new evidence suggests otherwise. There is also no evidence that patients who have undergone splenectomy are at higher risk of developing infection from dental procedures than is the general population. These patients are, however, more susceptible to infections from encapsulated organisms such as Pneumococcus and Hemophilus type B species; physicians often recommend the use of antibiotic prophylaxis for invasive dental procedures in such cases.

DENTAL PROCEDURES AND ANTIBIOTIC PROPHYLAXIS

The link between dental procedures and IE remains a controversial subject. In 1984, Guntheroth reported a low incidence of bacteremia associated with dental procedures and suggested that meticulous oral hygiene was more important in the prevention of IE than any antibiotic regimen. In a population-based control study involving 273 patients with cardiac lesions, Strom and colleagues found that dental procedures were not a risk factor for IE, even in patients with valvular abnormalities. Furthermore, even when the recommended antibiotic regimen was administered, it was not 100 percent effective in preventing IE.

The evidence is now clear that not all dental procedures warrant the use of antibiotic prophylaxis. It is safe to perform dental procedures (such as restorative and prosthetic treatment) in which the potential for bleeding is minimal in at-risk patients without the use of antibiotic prophylaxis. Invasive treatment in which bacteremia is more likely to occur (such as periodontal scaling, periodontal surgery and dental extractions) warrant the use of antibiotic coverage in patients with specific conditions, such as prosthetic heart valves and a history of endocarditis.

SUMMARY

As a result of greater understanding of disease processes, an enhanced awareness of cost-effectiveness and risk-benefit correlations, and better communication between medical and dental practitioners, the guidelines for antibiotic prophylaxis have been significantly altered. Although the major impetus for this change was related to prevention of IE, situations involving prosthetic joints and patients with compromised immune systems also have been reconsidered. In addition, the specific nature of dental procedures and the risk of patients’ developing bacteremias from them have been reconsidered, and many common procedures have been excluded from the list of those that require prophylaxis. It is clear that the trend is toward covering fewer and more specific medical conditions for a limited number of invasive dental procedures. Although some situations are well-delineated, controversy and concern over others continue. Further investigation and research are needed to clarify these issues.

Calcium Hydroxide and Chlorhexidine as root canal irrigants

The mechanical instrumentation must be augmented  with antimicrobial irrigant.  Sodium hypochlorite - similar to Clorox Bleach - is almost universally the irrigant of choice in root canal treatment, and has been for many, many years.  Various  strengths of it are used but the research  shows a wide range of  helpful dilutions with not much difference in effect.  It is very helpful for a couple of reasons.  First it is highly antimicrobial for the vast majority of bacteria, viruses, spores, fungi and protozoa found in root canals. Secondly it chemically  helps to actually "dissolve" remaining bits of tissue that could not be removed with the  metal instruments.   It is  the only irrigant that can disrupt and remove  microbial biofilm from the infected  root canal system.  Research, however, has shown that Sodium hypochlorite, while almost universally depended on, will not completely kill all the bacteria in the tooth in up to at least  50% of cases studied.   Research over many, many years has shown that the addition  of Calcium hydroxide as a medication inside the canal significantly further reduced bacteria.
Other medications commonly used like CMCP or phenol only succeeded in about 66% of cases.  Other research using Calcium Hydroxide, but  for  SHORTER periods of  time, like one or two weeks, showed no significant improved effectiveness over the CMCP or Phenol.  It seems very important to me to leave the Calcium Hydroxide in the canals for at least 4 weeks for maximum effectiveness.
While Calcium Hydroxide does many wonderful things, it has been found to lack in one area.  There are two microbes important in root canal treatment that it does not kill:     Candida and E- faecalis.  When root canal treatment fails as it sometimes does, very often E faecalis is found in the re-infected canals and it is often thought to be responsible for the failure.  Fortunately, chlorhexidine has been found to be very  effective against it.  
Mixtures of chlorhexidine and Calcium Hydroxide have been shown to have additive benefit against Candida and E- faecalis. That is, the mixture is  more effective than either one alone. It's effective in reducing discomfort and promoting good healing.
Chlorhexidine, which  is seen or used in the form of "Peridex", a prescription mouth rinse for periodontal problems, can be used along with Sodium hypochlorite as a canal irrigant. It  is safe and innocuous except to the  germs that  reside in the mouth and root canals!

Sodium Hypochlorite as an root canal Irrigant

Sodium hypochlorite (NaOCl) in various concentrations is the most widely used

endodontic irrigant, but it can be an irritant to vital tissues. There are several

reports about the complications of irrigation with NaOCl during root canal therapy.

Most of the complications are the result of accidental extrusion of the solution from

the apical foramen or accessory canals or perforations into the periapical area. This

article is a review and comparison of all reported NaOCl accidents in the literature.

The impetus behind root canal cleaning and shaping is the elimination of tissue remnants,

bacteria, and toxins from the root canal system. This is generally accepted to be a major

factor in the success of root canal treatment. Mechanical procedures alone are insufficient

for total canal cleaning. Residual pulpal tissue, bacteria, and dentin debris may persist in

the irregularities of canal systems. Therefore, irrigating solutions should support and

complement endodontic preparation. These irrigants should flush out dentin debris,

dissolve organic tissue, disinfect the canal system, and provide lubrication during

instrumentation, without irritating the surrounding tissues. Some of the irrigants currently

used include hydrogen peroxide, physiologic saline, water, sodium hypochlorite (NaOCl),

chlorhexidine, and electrochemically activated water.

Because of its physicochemical and antibacterial properties, NaOCl is one of the most

popular irrigants.It is an inexpensive, readily available, and easily used chemical that usually rates well in

research.

A variety of NaOCl concentrations ranging from 0.5% to 5.25% have been advocated, as

well as a variety of temperatures. The longer the solution can remain in contact with

tissue, the higher the temperature of the solution, and the higher the concentration, the

greater the ability of NaOCl to dissolve the tissue.The optimum concentration for use

clinically is still a matter of controversy. Consequently, the clinician must decide on the

concentration and temperature of the NaOCl and the potential consequences of this

choice.

Advantages of NaOCl

The ability of NaOCl to dissolve organic soft tissue of the pulp and predentin is a result

of oxidation. The powerful oxidative activity of hypochlorite not only dissolves the

pulpal and dentinal tissue but also acts as a potent antimicrobial agent. It is well

recognized to be effective against a broad range of pathogens: gram-positive and gramnegative

bacteria, fungi, spores, and viruses including the human immunodeficiency

virus.

NaOCl, especially when used in high concentrations, is known to be effective in

dissolving organic tissue remnants and disinfecting the canal system.Effective

concentrations of NaOCl range from 2.6% o 5.25%. The dilution of NaOCl was

suggested because it has been proved that concentrations over 0.5% are cytotoxic.

Compared with a chlorhexidine gel, NaOCl not only has a higher capacity to kill

microorganisms but is also more able to remove cells from the root canal.Water is not

effective in removing dentine debris from grooves in the apical portion of root canals.

Disadvantages of NaOCl

Acute inflammation followed by necrosis results when NaOCl comes into contact with

vital tissue. It causes severe inflammation and cellular destruction in all tissues except

heavily keratinized epithelium.The cytotoxic effect of 5.25% NaOCl on vital tissues,

resulting in hemolysis, is well documented, and its use warrants proper care. The clinical

efficacy of NaOCl relates to its nonspecific ability to oxidize, hydrolyze, and osmotically

draw fluids out of tissues.

The severity of the reaction depends on the concentration of the solution, its pH, and the

duration of exposure. NaOCl has a pH of 11 to 12.5, which causes injury primarily by

oxidation of proteins. In high concentrations, severe necrotic changes could be

observed. The higher concentrations also have some irritating effects on the periodontal

ligament.One report cites periodontal side effects of NaOCl with lower

concentrations. However, when confined to the canal space as an intracanal endodontic

irrigant, clinical toxicity of NaOCl is no greater than the clinical toxicity of normal saline

solution.

NaOCl causes vascular permeability in blood vessels, probably as a result of damage to

the vessels as well as the release of chemical mediators, such as histamine, from involved

tissue. This characteristic causes immediate swelling and often profuse bleeding through

the root canal when NaOCl is not used properly as an endodontic irrigant.

There is only 1 report of hypersensitivity to NaOCl, which can easily be detected by skin

patch testing.There are reports about the effects of improper use of NaOCl, including

inadvertent injection into the maxillary sinus or splashing solution into the eyes. The

extrusion of NaOCl can cause facial nerve weakness in addition to other soft-tissue

damage.In addition to its toxicity to vital tissues, NaOCl has an unpleasant odor and

causes damage if it comes into contact with clothing.

There are 2 reports of inadvertently injecting NaOCl instead of anesthetic solution. One

resulted in severe palatal tissue necrosis,and the second involved edema in the

pterygomandibular space and peritonsillar and pharyngeal areas because of mandibular

block injection with NaOCl instead of anesthetic solution. In the second case, the patient

was admitted to an intensive care unit for probable airway obstruction and given opioid

analgesic intravenously for pain reduction.Damage to permanent tooth follicles,

peripheral tissue, and oral mucosa have been reported during careless NaOCl use in

pediatric endodontics.There are only a small number of cases in the literature that have

reported postoperative skin complications, long-term paresthesia, and altered nerve

sensations arising from the use of NaOCl as an endodontic irrigant.

There are 23 reported cases of NaOCl accidents in the literature. Almost all of

the cases have similar sequelae including severe pain, edema, and profuse hemorrhage

both interstitially and through the tooth. The reports mentioned several days of increasing

edema and ecchymosis accompanied by tissue necrosis and paresthesia; in some cases,

secondary infections have been observed. Most of the cases had complete resolution

within a few weeks but a few were marked by long-term paresthesia or scarring.

Remaining residual paresthesia indicates some permanent damage to the nerve endings in

the affected area.

NaOCl Accident Management

Proper management of a NaOCl accident is important for achieving the best outcomes.

The following lists some important factors for managing a NaOCl accident:

• Early recognition of the problem; the patient should be informed of the cause and

nature of the accident (Table 2, see end of the article)

• Immediate irrigation of the canal with normal saline to dilute the NaOCl

• Allow bleeding response to flush the irritant out of the tissues

• Reassure patient

• Provide patient with both verbal and written home care instructions

• Monitor the patient

After the NaOCl accident has been recognized and the patient has been informed, the

authors recommend a treatment that focuses on palliative care, including cold and warm

compresses, saline rinses, pain control, prophylactic antibiotics, steroid therapy, and

monitoring (Table 3). It is important to reassure the patient throughout treatment because

of the amount of time it will take for the inflammation to resolve.

Avoiding NaOCl Accidents

The following steps can help clinicians avoid NaOCl accidents:

• Adequate access preparation

• Good working length control

• Irrigation needle placed 1 mm to 3 mm short of working length

• Needle placed passively and not locked in the canal

• Irrigant expressed into the root canal slowly

• Constant in and out movements of the irrigating needle into the canal space

• "Flowback" of solution as it is expressed into the canal should be observed

• Use side delivery needles that are specifically designed for endodontic purposes

Discussion

NaOCl is tissue cytotoxic. When it comes into contact with tissue, it causes hemolysis

and ulceration, inhibits neutrophil migration, and damages endothelial and fibroblast

cells.Incorrect determination of working length, lateral perforation, and wedging of

the irrigating needle are the most common procedural accidents associated with adverse

NaOCl reactions.

The optimal clinical concentration of NaOCl is still controversial. A 1% concentration of

NaOCl provides tissue dissolution and an antimicrobial effect, but the concentration

reported in the literature has been as high as 5.25%.Evidence demonstrates that high

concentrations of NaOCl have enhanced antimicrobial activity.Irrigation time may

increase the antimicrobial effect of endodontic irrigants without affecting the surrounding

tissues. It has been found that 0.5% NaOCl had nearly the same bactericidal effect as

5.25% NaOCl when used for 30 minutes.

After a NaOCl accident, early and aggressive treatment is advocated to reduce potentially

serious complications. The use of antibiotics is recommended because there is a

possibility of tissue necrosis and infection.Steroids also may be useful.

Depending on the degree of injury, some cases might require surgical intervention. The

aim of any surgical procedure should be to provide decompression and facilitate drainage,

and to create an environment conducive to healing. The other advantage of surgery is

meticulous debridement of grossly necrotic tissue and direct irrigation of affected sites.

Conclusion

NaOCl is an effective antibacterial agent but can be highly irritating when it comes in

contact with vital tissue. Most of the reported complications occurred because of

incorrect determination of endodontic working length, iatrogenic widening of the apical

foramen, lateral perforation, or wedging of the irrigating needle. If a perforation or open

apex exists, then great care should be exercised to prevent a NaOCl accident or an

alternative irrigation solution should be considered.

Table 2—How to recognize a NaOCl accident

• Immediate severe pain (for 2-6 minutes)

• Ballooning or immediate edema in adjacent soft tissue because of perfusion to the loose

connective tissue

• Extension of edema to a large site of the face such as cheeks, peri- orbital region, or lips

• Ecchymosis on skin or mucosa as a result of profuse interstitial bleeding

• Profuse intraoral bleeding directly from root canal

• Chlorine taste or smell because of injected NaOCl to maxillary sinus

• Severe initial pain replaced with a constant discomfort or numbness, related to tissue

destruction and distension

• Reversible or persistent anesthesia

• Possibility of secondary infection or spreading of former infection

Table 3—How to treat a NaOCl accident

• Remain calm and inform the patient about the cause and nature of the complication.

• Immediately irrigate with normal saline to decrease the soft-tissue irritation by diluting

the NaOCl.

• Let the bleeding response continue as it helps to flush the irritant out of the tissues.

• Recommend ice bag compresses for 24 hours (15-minute intervals)to minimize swelling.

• Recommend warm, moist compresses after 24 hours (15-minute intervals).

• Recommend rinsing with normal saline for 1 week to improve circulation to the

affected area.

• For pain control

• Initial control of acute pain could be achieved with anesthetic nerve block.

• Acetaminophen-based narcotic analgesics for 3 to 7 days (NSAID analgesic should be

avoided to decrease the amount of bleeding into the soft tissues).

• Prophylactic antibiotic coverage for 7 to 10 days to prevent secondary infection or

spreading of the present infection.

• Steroid therapy with methylprednisolone for 2 to 3 days to control inflammatory

reaction.

• Daily contact to monitor recovery.

• In severe cases such as respiratory distress, accessing the local emergency service via

108 is appropriate.

• Reassure the patient about the lengthy resolution of the inflammatory reaction.

• Provide the patient with both verbal and written home care instructions.

• Monitor the patient for pain control, secondary infection, and reassurance.