Denture Hygiene as It Relates to Denture Stomatitis: A Review

Between 2000 and 2010, the population aged 65 and older grew 15.1%, while the total US population grew 9.7%. The opposite happened between 1990 and 2000 when the growth of the older population was slower than that of the total population, with growth rates of 12% and 13.2%, respectively.¹ According to the American College of Prosthodontics, approximately 15% of the edentulous population has dentures made each year. More than 36 million Americans are fully edentulous, and 120 million people in the United States are missing at least one tooth, and these numbers are expected to grow in the next two decades.² The Centers for Disease Control and Prevention states that almost 20% of adults aged 65 or older have lost all of their teeth.³ Complete tooth loss is twice as prevalent among adults aged 75 and older (26%) compared with adults aged 65 to 74 (13%).⁴ In short, there are many edentulous people in need of dentures.

The wear of dentures carries with it the possibility of an inflammatory response by the denture-bearing tissues. Denture stomatitis (DS) is a chronic inflammation localized to the denture-bearing mucosa (the basal seat).⁵ DS may also be generalized in nature.⁶ Clinically, the tissue covered by the appliance, especially one made of acrylic, is erythematous and smooth or granular.⁷ It can have petechial hemorrhage. The exact cause of DS is controversial and may even be multifactorial. The predominant belief is that Candida albicans is strongly associated with DS, yet biopsy specimens of DS seldom show candida hyphae actually penetrating the keratin layer of the host epithelium.⁵ This condition is rarely asymptomic⁵ and is often accompanied by a burning sensation,⁷ is associated with pain, and is often seen in the maxilla. This could result from an ill-fitting mandibular denture that does not lend itself to patient use, poorly fabricated dentures, or poor patient compliance.

Patient treatment is determined by the cause of the problem. Treatment may include evaluation of systemic health (eg, diabetes mellitus), ensuring proper fit of the prosthetic appliance (considerations include reline, rebase, fabrication of new dentures, and prosthetic design), improving hygiene associated with the appliance, controlling fungal infection (with, for example, amphotericin, nystatin, or miconazole),⁸ generating artificial saliva, and cessation of smoking. Some cases may not respond to these methods of treatments, and therefore a biopsy is indicated along with topical steroid therapy to rule out mucositis (an allergic reaction to denture material).⁷

Candida-associated DS has been correlated with a lack of denture hygiene.⁹ Various methods can be used to assist patients with hygiene. The use of over-the-counter disinfection tablets in a water basin has shown to decrease the bacteria count on a denture; however, this method does not affect the C. albicans flora.¹⁰ One study reported that patients aged 60 to 80 primarily cleaned their dentures with a toothbrush and water.¹¹ Felton et al determined that daily removal of the bacterial biofilm present in the oral cavity and on the dentures is crucial to minimizing DS and contributing to good oral and general health.¹²

Sodium hypochlorite has been shown to be effective against different microorganisms. The 0.5% sodium hypochlorite solution was the most effective and might be used to control denture biofilm.^13,14 Dentures should not be soaked in sodium hypochlorite for more than 10 minutes.¹² Repeated soaking in sodium hypochlorite may cause discoloration of the denture. Da Silva et al determined that 1% sodium hypochlorite, 2% glutaraldehyde, and 2% chlorhexidine gluconate were most effective against microorganisms followed by 100% vinegar.¹⁵ In their review, de Souza et al found "weak" evidence in support of soaking dentures in effervescent tablets or enzymatic solutions, and that brushing with paste can remove plaque and kill microbes better than inactive treatments.¹⁶ They also stated, however, that it was unclear which was the most effective method.

Chlorhexidine digluconate (CHX), cetylpyridinium chloride (CPC), or triclosan solutions inhibit bacteria.¹⁷ Machado et al showed that chlorhexidine decreases the colonization of C. albicans.¹⁸ CHX, CPC, and sanguinarine mouthwashes have been shown to be effective against C. albicans; mouthrinses containing antimicrobial agents might represent an appropriate alternative to conventional antifungal drugs in the management of oral candidiasis.¹⁹ CHX, CPC, and their combination (CHX-CPC) have inhibitory effects on C. albicans, and rinsing with mouthwashes containing these active ingredients will prove beneficial to patients.²⁰

Shay called the use of a table-top ultrasonic cleaner a "more effective mechanical approach to denture cleaning."²¹ He acknowledged that its usage is limited by lack of professional instruction and common knowledge by laypersons; however, cleaning patients' dentures with an ultrasonic cleaner in an institution or office setting is recommended.²¹ Shay indicated the use of a denture brush specifically designed for the purpose of denture cleaning.²¹ Felton et al suggested that daily cleaning of dentures with a non-abrasive denture cleanser is effective.¹² Hard-bristle toothbrushes and abrasive toothpastes and cleansers have been shown to abrade the acrylic, allowing easier growth of bacteria and C. albicans. In the United States, the dominant manner of denture maintenance is the use of an effervescent commercial denture cleansing product dissolved in water.²¹

Using a microwave after placing the denture in an ultrasonic scaler or brushing also has been recommended.²¹ While microwave disinfection is being tested, there are conflicting reports about its effectiveness, which power to use, and the time needed for disinfection while also preventing acrylic resin deformation. Color changes have been noted with microwave disinfection.²² Papadiochou and Polyzois concluded that effervescent tablets combined with mechanical cleaning was more effective for denture sanitation compared to mechanical cleaning alone; however, the effects on C. albicans are conflicting.²² Brushing with dentifrice attained greater removal of biofilm area percentage compared with brushing with neutral pH gel soap.²² They also determined that the use of alkaline peroxide, 0.5% sodium hypochlorite, and CHX was effective, too. Color change has also been noted. It has been stated that contrary to recommendations from dental and allied professionals, many individuals wearing dentures (either partial or complete) do not remove the appliances at night, and as a result, denture-bearing tissues do not get a chance to rest or receive the benefits associated with the properties of the antibacterial agents naturally present in saliva.²³

Clinicians have a responsibility to the patient to provide a well-fitting, relatively self-cleansing denture regardless of the patient's insurance. Ill-fitting dentures traumatize the oral mucosa, creating an irritation; they need to be relined or remade to prevent DS and plaque accumulation (Figure 1 and Figure 2). Proper preliminary and secondary impression-making techniques must be followed to help ensure a maximized peripheral seal. The proper vertical dimension of occlusion must be determined. In addition, during the festooning of the denture, the wax should be convex and smooth, not concave and rough. Improper festooning (Figure 3 and Figure 4) can result in food accumulation and contribute to plaque accumulation (Figure 5 and Figure 6). Stippling (Figure 3) makes it difficult to keep the denture clean. Properly made and fitting dentures will cause fewer problems for both the patient and clinician. Also, if a patient has manual dexterity issues, an electric toothbrush may be recommended to help disinfect the dentures with dentifrice.

The authors recommend that during the course of treatment clinicians reiterate the hygiene instructions with patients repeatedly and ensure that patients have an understanding of their responsibilities. Hygiene instructions could include the following: Patients should place a towel in the sink to help prevent fracturing the teeth and acrylic base. After eating, they should brush their denture with a soft-bristle toothbrush and non-abrasive liquid soap,¹² making sure that the entire denture is cleaned; this will minimize food debris accumulation and staining (Figure 7 and Figure 8). Soap suds should form as proper denture hygiene is performed, especially in the embrasures (Figure 9 and Figure 10). Dentures should be placed in soaking tablets nightly following the manufacturer's recommendation. After instructions are followed, the dentures should be left to soak in a water basin overnight with fresh, clean water that is replaced daily. Upon removal from the basin, the denture should be rinsed well to remove any chemical debris left behind. Patients should be informed that denture cleansers are only to be used to clean dentures outside of the mouth.¹² Dentures should never be placed in hot water, nor should they be stored in water when not in use due to distortion factors upon drying out.

Clinicians should reinforce to their patients to not wear the dentures at night to allow tissue oxygenation and prevent the moist, hot environment in which C. albicans can prevail. This will also allow the tissue to rest by avoiding unnecessary compression. Regular intraoral examination of the patient and examination of the denture is advised to help prevent future problems.

It is imperative for dentists as professional caregivers to take the time to instruct patients on proper denture disinfection procedures and the importance of cleaning the dentures well at least once daily. Denture hygiene and denture removal prior to sleeping helps prevent DS and allows the tissue to attain a state of homeostasis. Patient education is essential to helping denture-wearing patients maintain good oral health.

The primary author (Dr. Galvan) would like to thank the co-authors for their dedication and contribution this article.

The authors had no disclosures to report.

Ray Galvan, DDS
Assistant Professor, Department of Prosthodontics, College of Dentistry, University of Tennessee, Memphis, Tennessee

Michael McBride, DDS
Associate Professor, Department of Prosthodontics, College of Dentistry, University of Tennessee, Memphis, Tennessee

Tom V. Korioth, DDS, PhD
Professor, Department of Prosthodontics, College of Dentistry, University of Tennessee, Memphis, Tennessee

Franklin Garcia-Godoy, DDS, MS, PhD, PhD
Professor, Department of Bioscience Research, College of Dentistry, University of Tennessee, Memphis, Tennessee