Oral mucosal lesions associated with the wearing of removable dentures

Salivary opiorphin levels in denture-related traumatic ulcers

OBJECTIVE

Opiorphin is a pentapeptide secreted in saliva and has a strong analgesic effect. Salivary opiorphin has been shown to increase in orofacial pain and may act as a pain reliever in pain caused by denture-related ulcers. The current study aimed to evaluate the salivary opiorphin levels in traumatic ulcers caused by ill-fitting dentures and demonstrate whether there is any correlation between trauma-related pain levels and salivary opiorphin levels.

MATERIALS AND METHODS

Twenty-two individuals with new full dentures and a complaint of pain due to ill-fitting were included in this study. Patients were asked to rate their level of pain on a visual analog scale (VAS). Then, saliva specimens were collected at the first visit with the complaint of pain and 7 days following the denture adjustment.

RESULTS

The average saliva opiorphin level before and after denture adjustment were 19.29 ± 5.44 and 15.78 ± 3.95 ng/mL, respectively. A dependent (paired) t-test determined that the mean salivary opiorphin level differed statistically significantly before and after the adjustment of the dentures.

CONCLUSIONS

The findings show that salivary opiorphin levels increase in pain associated with denture-related traumatic ulcers. Adjusting the dentures resulted in pain relief and a statistically significant reduction in opiorphin levels.

Association of Salivary Cortisol With Anxiety in Type 2 Diabetes Mellitus Patients Before and After Complete Denture Rehabilitation: An In-Vivo Analysis

Background Complete edentulism negatively impacts emotional, physical, social, and psychological well-being, leading to a decline in quality of life and heightened stress and anxiety. Stressful situations associated with edentulism can elevate cortisol levels, potentially increasing the risk of diabetes. Rehabilitation with complete dentures needs careful evaluation for its impact on general health, considering stress points and systemic effects. This study aimed to assess salivary cortisol levels in type 2 diabetes mellitus patients before and after complete denture rehabilitation, highlighting the intricate relationship between diabetes, cortisol, and the stress response. Methods This is a cross-sectional study centered on individuals with diabetes who were completely edentulous and undergoing evaluation by the outpatient prosthodontic department. Glycated hemoglobin, anxiety levels, and the fabrication of complete dentures were all accomplished with the participants' consent. Patients underwent evaluations before and one month after receiving complete denture rehabilitation. Results An absolute correlation between salivary cortisol levels and anxiety may be established because anxiety levels dramatically decreased during complete denture rehabilitation. Conclusion By learning how the patient's general health is related to their new set of complete dentures and how to correlate that information with dental rehabilitation, professionals can help patients better adapt to their new set of dentures.

Pathophysiology of Medication-Related Osteonecrosis of the Jaw-A Minireview

Medication-related osteonecrosis of the jaw (MRONJ) is a rare but serious adverse effect of antiresorptive medications administered for control of osseous malignancy, osteoporosis, or other bone metabolic diseases. Despite being reported in the literature two decades ago, MRONJ etiology, pathophysiology, and progression remain largely unknown, and current nonoperative or operative treatment strategies are mostly empirical. Several hypotheses that attempt to explain the mechanisms of MRONJ pathogenesis have been proposed. However, none of these hypotheses alone is able to capture the complex mechanistic underpinnings of the disease. In this minireview, we aim to highlight key findings from clinical and translational studies and propose a unifying model for the pathogenesis and progression of MRONJ. We also identify aspects of the disease process that require further investigation and suggest areas for future research efforts toward calibrating methodologic approaches and validating experimental findings. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Oral Health Factors Related to Rapid Oral Health Deterioration among Older Adults: A Narrative Review

Older adults who face systemic health issues and lack adequate social support are at risk for oral health deterioration. How rapidly such changes take place depends on the severity of their medical condition and their ability to access oral health services in a timely manner. The management of dental caries and periodontal disease in this cohort is made complex by the interaction of local and host factors such as the presence of dry mouth, involvement of root surfaces, and altered wound healing. in addition to enhanced maintenance needs to avoid recurrence or progression. Tooth replacement can be beneficial in restoring oral function, allowing patients to enjoy a healthy and nutritious diet but requires careful consideration to avoid further damage to remaining dental units. Establishing a dental home for the older adult can facilitate routine surveillance, disease prevention, and patient/caregiver education to achieve oral health goals commensurate with overall health. This narrative review details oral health factors that are related to rapid oral health deterioration among older adults.

Characterization of the Oral Microbiome in Wearers of Fixed and Removable Implant or Non-Implant-Supported Prostheses in Healthy and Pathological Oral Conditions: A Narrative Review

Oral commensal microorganisms perform very important functions such as contributing to the health of the host. However, the oral microbiota also plays an important role in the pathogenesis and development of various oral and systemic diseases. The oral microbiome may be characterized by a higher prevalence of some microorganisms than others in subjects with removable or fixed prostheses, depending on oral health conditions, the prosthetic materials used, and any pathological conditions brought about by inadequate prosthetic manufacturing or poor oral hygiene. Both biotic and abiotic surfaces of removable and fixed prostheses can be easily colonized by bacteria, fungi, and viruses, which can become potential pathogens. The oral hygiene of denture wearers is often inadequate, and this can promote oral dysbiosis and the switch of microorganisms from commensal to pathogens. In light of what emerged from this review, fixed and removable dental prostheses on teeth and on implants are subject to bacterial colonization and can contribute to the formation of bacterial plaque. It is of fundamental importance to carry out the daily hygiene procedures of prosthetic products, to design the prosthesis to facilitate the patient's home oral hygiene practices, and to use products against plaque accumulation or capable of reducing oral dysbiosis to improve patients' home oral practices. Therefore, this review primarily aimed to analyze the oral microbiome composition in fixed and removable implant or non-implant-supported prostheses wearers in healthy and pathological oral conditions. Secondly, this review aims to point out related periodontal self-care recommendations for oral dysbiosis prevention and periodontal health maintenance in fixed and removable implant or non-implant-supported prostheses wearers.

Title: Chemotherapy-Induced Oral Complications and Prophylaxis Strategies

Cancer is currently a significant therapeutic challenge and is frequently connected with numerous adverse effects. Despite many improvements in chemotherapy, oral complications are common, leading to poor quality of life and chemotherapeutic dose reduction, which impair survival. This review summarizes the most common dental complications in patients receiving chemotherapy. We mainly focus on oral mucositis as it is a major cause of dose-limiting toxicity. Furthermore, oral candidiasis, viral infections, and xerostomia will be discussed. Conclusions: preventing complications is significantly more important than treating them. All patients beginning systemic anticancer treatment should undergo a thorough oral examination and get appropriate prophylaxis.

Comparative evaluation of bacterial colonization on removable dental prostheses in patients with COVID-19: A clinical study

STATEMENT OF PROBLEM

In the outbreak of COVID-19, coinfections and even superinfections in the background of SARS-CoV-2 viral infection have been reported. Such bacterial and fungal strains may be colonized in different tissues and organs, including the oral cavity. Whether infection with COVID-19 could increase colonization of different bacterial strains on removable dental prostheses is unclear.

PURPOSE

The purpose of this clinical study was to compare bacterial colonization on removable dental prostheses in patients with COVID-19, before versus after diagnosis.

MATERIAL AND METHODS

Two sex- and age-matched groups of complete-denture-wearing participants (N=60) with and without a positive diagnosis for COVID-19 were enrolled in the study. Swabs were used at 2 different time intervals to sample areas of the dentures, which were then cultured and the colony smears Gram stained. A statistical analysis was conducted by using the Mann-Whitney U test (α=.05).

RESULTS

Streptococcus species (93.3% versus 40.0%, P=.047) and Klebsiella pneumonia (46.7% versus 13.4%, P=.036) were detected more frequently in the COVID-19-positive group.

CONCLUSIONS

Higher rates of bacterial colonization, especially with Streptococcus species and Klebsiella pneumonia, were detected on removable dental prostheses after COVID-19 infection.

The Use of Acrylate Polymers in Dentistry

The manuscript aimed to review the types of acrylate polymers used in dentistry, as well as their chemical, physical, mechanical, and biological properties. Regarding their consistency and purpose, dental acrylate polymers are divided into hard (brittle), which includes acrylates for the production of plate denture bases, obturator prostheses, epitheses and maxillofacial prostheses, their repairs and lining, and soft (flexible), which are used for lining denture bases in special indications. Concerning the composition and method of polymerization initiation, polymers for the production of denture bases are divided into four types: heat-, cold-, light-, and microwave-polymerized. CAD/CAM acrylate dentures are made from factory blocks of dental acrylates and show optimal mechanical and physical properties, undoubtedly better monomer polymerization and thus biocompatibility, and stability of the shape and colour of the base and dentures. Regardless of the number of advantages that these polymers have to offer, they also exhibit certain disadvantages. Technological development enables the enhancement of all acrylate properties to respond better to the demands of the profession. Special attention should be paid to improving the biological characteristics of acrylate polymers, due to reported adverse reactions of patients and dental staff to potentially toxic substances released during their preparation and use.

The denture microbiome in health and disease: an exploration of a unique community

The United Nations suggests the global population of denture wearers (an artificial device that acts as a replacement for teeth) is likely to rise significantly by the year 2050. Dentures become colonized by microbial biofilms, the composition of which is influenced by complex factors such as patient’s age and health, and the nature of the denture material. Since colonization (and subsequent biofilm formation) by some micro‐organisms can significantly impact the health of the denture wearer, the study of denture microbiology has long been of interest to researchers. The specific local and systemic health risks of denture plaque are different from those of dental plaque, particularly with respect to the presence of the opportunist pathogen Candida albicans and various other nonoral opportunists. Here, we reflect on advancements in our understanding of the relationship between micro‐organisms, dentures, and the host, and highlight how our growing knowledge of the microbiome, biofilms, and novel antimicrobial technologies may better inform diagnosis, treatment, and prevention of denture‐associated infections, thereby enhancing the quality and longevity of denture wearers.

Antifungal Activity of Denture Base Resin Containing Nanozirconia: In Vitro Assessment of Candida albicans Biofilm

Objective

To evaluate the antimicrobial effects of different concentrations of zirconium dioxide nanoparticles (nano-ZrO₂) reinforcement of poly(methyl) methacrylate (PMMA) on surface roughness and C. albicans biofilm.

Methods

20 heat-polymerized acrylic resin discs were conventionally made and divided into 4 groups (n = 5) according to nano-ZrO₂ concentration: control (0% filler) and 3 experimental groups (2.5% (Z2.5), 5.0% (Z5.0), and 7.5% (Z7.5)). An optical profilometer was used for surface roughness evaluation, followed by Candida adherence assay. Specimens were sterilized, then immersed in cultured yeast (C. albicans), and incubated at 37°C for 48 hours. After that, discs were rinsed before extracting the clustered pellets of Candida. The attached C. albicans was counted using the direct method after spreading on agar media and incubating for 48 hours. Statistical analysis was performed using one-way ANOVA and Tukey's post hoc test at α = 0.05.

Results

Surface roughness was significantly increased with all modified groups compared with control (P < 0.01), which showed the lowest roughness value (0.027 ± 0.004 μm). There was no significant difference in the roughness value among reinforced groups (2.5, 5.0, and 7.5%) (P > 0.05), with Z7.5 showing the highest roughness value (0.042 ± 0.004 μm). Candida count was reduced as the nano-ZrO₂ increased but not significantly (P=0.15).

Conclusions

The addition of different concentrations of nano-ZrO₂ particles to PMMA increased the surface roughness compared with control; in contrast, insignificant reduction of C. albicans biofilm was detected.

Evaluation of the intaglio surface shape of implant-supported complete-arch maxillary prostheses and its association with biological complications: An analytical cross-sectional study

STATEMENT OF PROBLEM

Whether the shape of the intaglio surface of fixed implant-supported maxillary prostheses is associated with the occurrence of biological is unclear.

PURPOSE

The purpose of this cross-sectional study was to evaluate the shape (convex or concave) of the intaglio surface of complete-arch implant-supported maxillary fixed prostheses and to assess the association with biofilm accumulation, hyperemia, bone loss, and patient satisfaction.

MATERIAL AND METHODS

Study participants consisted of 56 individuals with fixed complete implant-supported maxillary prosthesis attending follow-up appointments. The 56 prostheses supported by 388 implants had been in place for an average of 5.5 years (range 1-14 years). The intaglio surface was divided into areas corresponding to the cantilever regions and between implants (n=442) and was assessed for shape (concave or convex) and biofilm index (0 to 3). Tissue hyperemia (redness) was assessed as absent or present. Bone loss (mm) was measured from digital periapical radiographs by 2 calibrated evaluators (kappa=94.9%). Study participant satisfaction was investigated by using a visual analog scale. Association assessments (α=.05) between the shape of each area and all these parameters were performed with the Friedman, linear regression, and logistic regression tests.

RESULTS

Of the analyzed areas, 58 (13.1%) were concave, and 384 (86.9%) were convex. Biofilm was absent on 3.5% of the concave and 5.5% of the convex areas. Biofilm was detectable with a probe on 12% of the concave and 22.4% of the convex areas and clinically visible in 58.6% of the concave and 57.8% of the convex areas. Abundant biofilm was seen in 25.9% of the concave and 14.3% of the convex areas and was associated with hyperemia (P=.003). A statistically significant association was found between the shape and biofilm accumulation (P=.009). Hyperemia was present in 199 (45%) areas. The association analysis between the shape of the area and the presence of hyperemia was not significant (P>.05). The mean bone loss was 0.71 mm (0.91 mm). Implants placed near concave areas underwent greater bone loss (P=.001). Study participants reported a high level of satisfaction with the esthetics, mastication, speech, and smile provided by the prosthesis, with satisfaction scores ranging between 8.46 and 8.77. However, in relation to ease of cleaning, only 19.6% were fully satisfied.

CONCLUSIONS

The shape of the intaglio surface of prostheses influenced the occurrence of biofilm accumulation and bone loss, and concave areas showed greater biofilm accumulation and bone resorption. High rates of satisfaction with treatment were identified.

Oral Medicine Considerations for Older Patients

With the projected increase to 1.3 billion people aged 65 years or older by 2040, healthcare professionals are faced with significant challenges in managing this population of patients. In the oral cavity, oral mucosal disease is a significant problem found in older populations. Several facial pain conditions are more likely to be seen in this cohort of patients. Although management of this group of patients may not always be appropriate in general practice, an awareness of the range of oral medicine conditions that may be encountered in older patients is essential to allow prompt referral and treatment.

Perceived Status and Care Practices among Complete Denture Wearers

Background:

Oral health is neglected even today. This can be evidently seen in the low utilization rates and poor oral health status. Conventional dentures are the most common treatment option in the restoration of lost teeth. Without appropriate denture care practices, there is an elevated risk of developing a multitude of problems. The aim of this study was to assess the perceived status and care practices among complete denture wearers in Modern Dental College and Research Centre, Indore, Madhya Pradesh, India.

Materials and Methods:

A cross-sectional study was conducted in the Department of Prosthodontics at the Modern Dental College and Research Centre, Indore, Madhya Pradesh, India. Patients with self-care optimum overall health who were using either single or full complete dentures for more than 1 year from the commencement of the study were requested to participate in the study. A total of 1000 study participants were given a self-administered questionnaire on their denture care practices followed by clinical examination of the denture status. Data were statistically analyzed using the Statistical Package for the Social Sciences software for Windows, version 20.0.

Results:

Maximum denture wearers informed that they cleaned their dentures once a day, with brush and water, and had the habit of removing the dentures before sleeping at night. Almost 90% of the participants reported their denture status to be good or fair. Clinical examination revealed that slightly more than half of the participants had poor denture status.

Conclusion:

This study signifies the importance for improvement in patient oral health education and counseling with respect to the maintenance of dentures and upkeep of denture hygiene. It also emphasizes the need for educating patients on how to evaluate the status of their dentures.

High Rate of Oral Candida Detection in Dependent Japanese Older People

The aim of this study was to clarify the association between oral Candida detection and the dependency status of older people. This study included 31 older people aged ≥70 years who had a certified need for long-term care or support and received care in a local day care center; it also included 27 independent older patients aged ≥70 years who visited Hiroshima University Hospital. Oral Candida was detected by a polymerase chain reaction using swab samples from the tongue surface. Oral moisture was significantly reduced in dependent older people, compared with independent older people (p = 0.003). There was a weak negative relationship between numbers of bacteria and levels of oral moisture (Spearman's rank correlation coefficient; R = -0.29, p = 0.01). Dependent older people exhibited a significantly higher rate of Candida albicans detection (35.5%) compared with independent older people (11.1%). Dependent older people also exhibited a higher rate of concurrent detection of both C. albicans and Candida glabrata (32.3%) compared with independent older people (11.1%), but this difference was not statistically significant. Thus, dependent older people may be more susceptible to oral C. albicans infection, compared with independent older people. Good oral hygiene is necessary to prevent oral Candida infection in dependent older people.

Applying the Host-Microbe Damage Response Framework to Candida Pathogenesis: Current and Prospective Strategies to Reduce Damage

Disease is a complex outcome that can occur as a result of pathogen-mediated damage, host-mediated damage or both. This has led to the revolutionary concept of the damage response framework (DRF) that defines microbial virulence as a function of host immunity. The DRF outlines six scenarios (classes) of host damage or beneficial outcomes, depending on the microbe and the strength of the immune response. Candida albicans is uniquely adapted to its human host and can exist as either a commensal, colonizing various anatomical sites without causing notable damage, or as a pathogen, with the ability to cause a diverse array of diseases, ranging from mucosal to invasive systemic infections that result in varying levels of microbe-mediated and/or host-mediated damage. We recently categorized six different forms of candidiasis (oropharyngeal, hematogenous, intra-abdominal, gastrointestinal, denture stomatitis, and vulvovaginitis) into independent DRF classes, supporting a contemporary view of unique mechanisms of pathogenesis for these Candida infections. In this review, we summarize the evidence for the pathogenesis of these various forms of candidiasis in the context of the DRF with the further intent to provide insights into strategies to achieve a level of host response or outcome otherwise, that limits host damage.

Guanylate-binding protein 6 is a novel biomarker for tumorigenesis and prognosis in tongue squamous cell carcinoma

OBJECTIVES

Guanylate-binding protein 6 (GBP6) is a member of the guanylate-binding protein family, and its role in cancer has not yet been reported. We aimed to investigate the clinical significance of GBP6 in oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

Next-generation sequencing was applied for analyzing differential gene expression profiling between corresponding tumor adjacent normal (CTAN) and tumor tissue from two paired OSCC patients. Real-time PCRs (RT-PCRs) were used to investigate the gene expression level of GBP6 of CTAN and tumor tissue samples from 14 TSCC patients. Immunohistochemistry was used to investigate the protein expression level of GBP6 in tumor tissues and paired CTAN tissues from 488 OSCC patients, including 183 buccal mucosa squamous cell carcinoma (BMSCC), 245 tongue squamous cell carcinoma (TSCC), and 60 lip squamous cell carcinoma (LSCC) patients.

RESULTS

Compared with CTAN tissues of OSCC patients, GBP6 is identified as a downregulated gene using the NGS platform, which was confirmed in 14 OSCC patients by RT-PCR. Moreover, protein expression level of GBP6 in tumor tissues was lower than that in CTAN tissues and the low GBP6 expression was correlated with poor cell differentiation/lymph node metastasis in TSCC patients. In addition, TSCC patients with low expression levels of GBP6 had poor disease-specific survival rate.

CONCLUSION

The low expression of GBP6 was associated with tumorigenesis and poor prognosis in OSCC patients, especially in TSCC patients.

CLINICAL RELEVANCE

GBP6 may serve as a novel favorable diagnostic and prognostic biomarker in TSCC patients.

Analysis of risk factors for maxillary denture-related oral mucosal lesions: A cross-sectional study

BACKGROUND

To evaluate the frequency of maxillary dentures-related lesions and the possible associated risk factors.

MATERIAL AND METHODS

Ninety-seven participants were selected, and a complete anamnesis, physical examination and tests of occlusion vertical dimension (OVD), retention and stability of the denture, biofilm quantification, cytopathology, sialometry, pH analysis and buffer capacity of the saliva were performed. Statistical analyses were performed with the Pearson's chi-square, Mann-Whitney tests, and Pearson's coefficient (p<0.05).

RESULTS

In 78% of the participants at least one denture-related lesion was found. Denture-associated stomatitis (63%), inflammatory fibrous hyperplasia (19%) and traumatic ulceration (11%) were the 3 most frequent lesions. The habit of night use of the denture was considered an independent risk factor for the development of oral lesions [OR=3.0 (95% CI 1.09-8.56); p<0.05]. Furthermore, the longest period of use of the same denture and biofilm also had statistically significant relation to oral lesions. The biofilm seems to be more related to the prevalence of oral lesions according to the multiple logistic regression [OR=1.3 (95% CI: 1.01-1.83) p<0.05]. The lack of a dentures' cleaning solution and detrition of the prothesis were independent risk factors for denture-associated stomatitis. Male gender, loss of OVD and bad buffer capacity were risk factors for angular cheilitis. Fractures of the base and repair of broken dentures were risk factors for traumatic ulcers.

CONCLUSIONS

These results show a high frequency of denture-related lesions. Besides, participants hygiene habits and poor quality of the dentures were the main factors for the development of these lesions.

Candida glabrata Has No Enhancing Role in the Pathogenesis of Candida-Associated Denture Stomatitis in a Rat Model

Many denture wearers suffer from Candida-associated denture stomatitis (DS), a fungal infection of the hard palate in contact with dentures. Biofilm formation by Candida albicans on denture/palate surfaces is considered a central process in the infection onset. Although Candida glabrata is frequently coisolated with C. albicans, its role in DS pathogenesis is unknown. We show here, using a contemporary rat model that employed a patented intraoral denture system, that C. glabrata established stable colonization on the denture/palate. However, in contrast to C. albicans inoculated rats, rats inoculated with C. glabrata exhibited minimal changes in weight gain or palatal tissue damage. Likewise, coinoculation with the two Candida species resulted in no exacerbation of C. albicans-induced DS pathology. Together, our findings indicate that C. glabrata has no inducing/enhancing role in DS pathogenesis.

Denture stomatitis (DS) is a condition characterized by inflammation of the oral mucosa in direct contact with dentures and affects a significant number of otherwise healthy denture wearers. Candida-associated DS is predominantly caused by Candida albicans, a dimorphic fungus that readily colonizes and forms biofilms on denture materials. Previous studies showed a requirement for Candida biofilm formation on both palate and dentures in infection and identified fungal morphogenic transcription factors, Efg1 and Bcr1, as key players in DS pathogenesis. While both C. albicans and Candida glabrata are frequently coisolated in mucosal candidiasis, a pathogenic role for C. glabrata in DS remains unknown. Using an established rat model of DS, we sought to determine whether C. glabrata alone or coinoculation with C. albicans establishes colonization and causes palatal tissue damage and inflammation. Rats fitted with custom dentures were inoculated with C. albicans and/or C. glabrata and monitored over a 4-week period for fungal burden (denture/palate), changes in body weight, and tissue damage via lactate dehydrogenase (LDH) release as well as palatal staining by hematoxylin and eosin (H&E) and immunohistochemistry for myeloperoxidase (MPO) as measures of inflammation. C. glabrata colonized the denture/palate similarly to C. albicans. In contrast to C. albicans, colonization by C. glabrata resulted in minimal changes in body weight, palatal LDH release, and MPO expression. Coinoculation with both species had no obvious modulation of C. albicans-mediated pathogenic effects. These data suggest that C. glabrata readily establishes colonization on denture and palate but has no apparent role for inducing/enhancing C. albicans pathogenesis in DS.

IMPORTANCE Many denture wearers suffer from Candida-associated denture stomatitis (DS), a fungal infection of the hard palate in contact with dentures. Biofilm formation by Candida albicans on denture/palate surfaces is considered a central process in the infection onset. Although Candida glabrata is frequently coisolated with C. albicans, its role in DS pathogenesis is unknown. We show here, using a contemporary rat model that employed a patented intraoral denture system, that C. glabrata established stable colonization on the denture/palate. However, in contrast to C. albicans inoculated rats, rats inoculated with C. glabrata exhibited minimal changes in weight gain or palatal tissue damage. Likewise, coinoculation with the two Candida species resulted in no exacerbation of C. albicans-induced DS pathology. Together, our findings indicate that C. glabrata has no inducing/enhancing role in DS pathogenesis.

Association between poor oral health and gastric cancer: A prospective cohort study

Poor oral health may be involved in the pathogenesis of gastric cancer, however, some aspects have not been explored. Further, for previously studied aspects, for example, tooth-loss, the findings are inconsistent. We conducted a prospective cohort study of 19,831 participants from Uppsala, Sweden, cancer-free at baseline in 1973-1974 and followed until 2012 through linkage to national registers. We found that individuals with fewest teeth at baseline had an increased risk of gastric cancer relative to subjects with all examined teeth present (p = 1.75e-2). Presence of denture-associated lesions was also associated with an increased risk of gastric cancer (p = 1.00e-4). However, these excess risks significantly varied with attained age; estimated hazard ratio (HR) at attained age 50 for tooth loss was 4.24 [95% confidence interval (CI) 1.83-9.80] and 5.91 (95% CI 2.76-12.63) for denture-associated lesions, decreasing at an estimated 4% and 6% per year respectively, resulting in HR of 1.54 (95% CI 0.90-2.64) for tooth loss and HR 1.29 (95% CI 0.90-1.85) for denture-associated lesions at attained age 75. No increased risk of gastric cancer was found for individuals with higher levels of dental plaque, or with Candida-related or tongue lesions. In conclusion, tooth-loss and denture-associated lesions are associated with increased risks of gastric cancer. Previous conflicting findings of tooth-loss and gastric cancer risk may partly be explained by the age-varying relative risk of gastric cancer.

Incorporation of the microencapsulated antimicrobial agent phytoncide into denture base resin

BACKGROUND

This study aimed to fabricate a denture base resin (DBR) containing phytoncide microcapsules (PTMCs) and determine the mechanical properties of the resin and antifungal activity.

METHODS

Fifty-four heat-cured rectangular DBR specimens (64 × 10 × 3.3 ± 0.2 mm) containing nine concentrations of PTMC between 0 and 5% (wt/wt) were fabricated and subjected to a three-point bending test. A phytoncide release bioassay was developed using DBR containing 0% and 2.5% PTMCs (wt/wt) in a 24 well-plate assay with incubation of Porphyromonas gingivalis at 37 °C for 74 h. The antifungal activity of PTMCs against Candida albicans, in a pH 5.5 acidic environment was determined in a plate assay.

RESULTS

Flexural strength decreased with increasing PTMC concentration from 97.58 ± 4.79 MPa for the DBR alone to 53.66 ± 2.46 MPa for DBR containing 5.0% PTMC. No release of phytoncide from the PTMCs in the DBR was detected at pH 7.4. The PTMCs had a minimal inhibitory concentration of 2.6% (wt/vol) against C. albicans at pH 5.5.

CONCLUSIONS

PTMCs can be added to DBR 2.5% (wt/wt) without adversely affecting flexural strength. PTMCs released the antimicrobial agent at pH 5.5 at concentrations sufficient to inhibit the growth of the C. albicans.

Effects on cytotoxicity and antibacterial properties of the incorporations of silver nanoparticles into the surface coating of dental alloys

The aim of this study was to research the changes in cytotoxicity and antibacterial properties after silver nanoparticles (AgNPs) were incorporated into the surface coating of dental alloys. AgNPs were attached to cobalt chromium alloys and pure titanium using a hydrothermal method, according to the reaction: AgNO₃+NaBH₄→ Ag+1/2H₂+1/2B₂H₆+NaNO₃. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate the cytotoxicity of the alloys when in contact with osteogenic precursor cells (MC3T3-E1) from mice and mesenchymal stem cells (BMSC) from rats. The antibacterial properties of dental alloys incorporating three different concentrations (10, 4, and 2 μmol/L) of AgNPs were tested on Staphylococcus aureus (SA) and Streptococcus mutans (MS). High cytotoxicity values were observed for all dental alloys that contained 0% of AgNPs (the control groups). The incorporation of AgNPs reduced cytotoxicity values. No significant difference was observed for antibacterial performance when comparing dental alloys containing AgNPs to the respective control groups. The results demonstrated that the cobalt chromium alloys and pure titanium all had cytotoxicity to MC3T3-E1 and BMSC and that the incorporation of AgNPs could reduce this cytotoxicity. The concentrations of AgNPs adopted in this study were found to have no antibacterial action against SA or MS.

Inhibitory effect of zirconium oxide nanoparticles on Candida albicans adhesion to repaired polymethyl methacrylate denture bases and interim removable prostheses: a new approach for denture stomatitis prevention

BACKGROUND

Despite drawbacks, cold-cured acrylic resin is still the most common material used in denture repair. Zirconia nanoparticles were among the reinforcements added to increase the strength of the resin. The effect on Candida due to the addition of zirconia nanoparticles to the resin has not been investigated.

PURPOSE

The aim of this study was to evaluate the effect of zirconia nanoparticles added to cold-cured acrylic resin on Candida albicans adhesion.

MATERIALS AND METHODS

A total of 120 acrylic resin specimens with dimensions measuring 22×10×2.5 mm3 were prepared and divided into two equal groups. One group (repair) comprised heat-polymerized specimens that were sectioned at the center and prepared to create a 2 mm repair area that was repaired with cold-cured resin reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. The second group contained intact cold-cured acrylic resin specimens reinforced with 0% wt, 2.5% wt, 5% wt, and 7.5% wt zirconia nanoparticles. Specimens were incubated at 37°C in artificial saliva containing C. albicans, and the effect of zirconia nanoparticles on C. albicans was assessed using two methods: 1) a slide count method and 2) a direct culture test. Variations in the number of living Candida were observed in relation to the different concentrations of zirconia nanoparticles. Analysis of variance (ANOVA) and post hoc Tukey's tests were performed for data analysis. If the P-value was ≤0.05, then the difference was considered as statistically significant.

RESULTS

It was found that C. albicans adhesion to repaired specimens was significantly decreased by the addition of zirconia nanoparticles (P<0.00001) in comparison with the control group. Intact cold-cured groups and groups repaired with cold-cured resin reinforced with 7.5% wt zirconia nanoparticles showed the lowest Candida count. Tukey's test showed a significant difference between the repaired group and the intact cold-cured group, while the later demonstrated a lower Candida count.

CONCLUSION

The addition of zirconia nanoparticles to cold-cured acrylic resin is an effective method for reducing Candida adhesion to repaired polymethyl methacrylate (PMMA) denture bases and cold-cured removable prosthesis.

CLINICAL SIGNIFICANCE

Based on the results of the current study, zirconia nanoparticles have an antifungal effect, which could be incorporated in the repair material for repairing denture bases and in PMMA removable prostheses as a possible approach for denture stomatitis prevention.

Transcription Factors Efg1 and Bcr1 Regulate Biofilm Formation and Virulence during Candida albicans-Associated Denture Stomatitis

Denture stomatitis (DS) is characterized by inflammation of the oral mucosa in direct contact with dentures and affects a significant number of otherwise healthy denture wearers. The disease is caused by Candida albicans, which readily colonizes and form biofilms on denture materials. While evidence for biofilms on abiotic and biotic surfaces initiating Candida infections is accumulating, a role for biofilms in DS remains unclear. Using an established model of DS in immunocompetent animals, the purpose of this study was to determine the role of biofilm formation in mucosal damage during pathogenesis using C. albicans or mutants defective in morphogenesis (efg1^-/-) or biofilm formation (bcr1^-/-). For in vivo analyses, rats fitted with custom dentures, consisting of fixed and removable parts, were inoculated with wild-type C. albicans, mutants or reconstituted strains and monitored weekly for fungal burden (denture and palate), body weight and tissue damage (LDH) for up to 8 weeks. C. albicans wild-type and reconstituted mutants formed biofilms on dentures and palatal tissues under in vitro, ex vivo and in vivo conditions as indicated by microscopy demonstrating robust biofilm architecture and extracellular matrix (ECM). In contrast, both efg1^-/- and bcr1^-/- mutants exhibited poor biofilm growth with little to no ECM. In addition, quantification of fungal burden showed reduced colonization throughout the infection period on dentures and palates of rats inoculated with efg1^-/-, but not bcr1^-/-, compared to controls. Finally, rats inoculated with efg1^-/- and bcr1^-/- mutants had minimal palatal tissue damage/weight loss while those inoculated with wild-type or reconstituted mutants showed evidence of tissue damage and exhibited stunted weight gain. These data suggest that biofilm formation is associated with tissue damage during DS and that Efg1 and Bcr1, both central regulators of virulence in C. albicans, have pivotal roles in pathogenesis of DS.

Effect of Storage in Distilled Water for Three Months on the Antimicrobial Properties of Poly(methyl methacrylate) Denture Base Material Doped with Inorganic Filler

The colonization of poly(methyl methacrylate) (PMMA) denture base materials by pathogenic microorganisms is a major problem associated with the use of prostheses, and the incorporation of antimicrobial fillers is a method of improving the antimicrobial properties of these materials. Numerous studies have demonstrated the initial in vitro antimicrobial effectiveness of this type of material; however, reports demonstrating the stability of these fillers over longer periods are not available. In this study, silver sodium hydrogen zirconium phosphate was introduced into the powder component of a PMMA denture base material at concentrations of 0.25%, 0.5%, 1%, 2%, 4%, and 8% (w/w). The survival rates of the gram-positive bacterium Staphylococcus aureus, gram-negative bacterium Escherichia coli and yeast-type fungus Candida albicans were established after fungal or bacterial suspensions were incubated with samples that had been previously stored in distilled water. Storage over a three-month period led to the progressive reduction of the initial antimicrobial properties. The results of this study suggest that additional microbiological tests should be conducted for materials that are treated with antimicrobial fillers and intended for long-term use. Future long-term studies of the migration of silver ions from the polymer matrix and the influence of different media on this ion emission are required.

Biomechanics of oral mucosa

The prevalence of prosthodontic treatment has been well recognized, and the need is continuously increasing with the ageing population. While the oral mucosa plays a critical role in the treatment outcome, the associated biomechanics is not yet fully understood. Using the literature available, this paper provides a critical review on four aspects of mucosal biomechanics, including static, dynamic, volumetric and interactive responses, which are interpreted by its elasticity, viscosity/permeability, apparent Poisson's ratio and friction coefficient, respectively. Both empirical studies and numerical models are analysed and compared to gain anatomical and physiological insights. Furthermore, the clinical applications of such biomechanical knowledge on the mucosa are explored to address some critical concerns, including stimuli for tissue remodelling (interstitial hydrostatic pressure), pressure–pain thresholds, tissue displaceability and residual bone resorption. Through this review, the state of the art in mucosal biomechanics and their clinical implications are discussed for future research interests, including clinical applications, computational modelling, design optimization and prosthetic fabrication.

Relationship between removable prosthesis and some systemics disorders

This article reviews the dental literature concerning the potential impact of the removable prosthesis (RP) on the health status of patients with certain systemic diseases. Literature was surveyed using Medline/PubMed database resources, as well as a manual search, up to 2015 to identify appropriate articles that addressed the aim of this review. The research used keywords about associations between RP and six pathologies: Human immunodeficiency virus infection, diabetes mellitus, pulmonary diseases, gastric-Helicobacter pylori, cancer, and cardiovascular diseases. Analysis of literature showed that in patients with dentures having one or more of the six general conditions listed, Candida albicans organism is more frequently found in the oral flora compared to healthy denture wearer. Although causality has not been established and pending further research on this topic, the hygienic practices necessary to minimize the risk of numerous pathologies should be strengthened in the case of these patients, all the more in the presence of physical or psychological disability. The relationship between the general diseases and increasing of oral candidiasis denture patients is not explained. Therefore, attention to oral hygiene and professional care for removing C. albicans may be beneficial in these medically compromised patients.

A study of the emotional effects of tooth loss in an edentulous Gujarati population and its association with depression

Context:

To fully estimate the burden of illness due to edentulism and establish valid treatment outcomes measures in this regard, it is equally important to study its psychosocial repercussions.

Aims:

The aim was to conduct a study to explore the emotional reactions to tooth loss, screen for current depressive symptoms and test for association between the two; among an edentulous Gujarati population.

Settings and Design:

A total of 147 edentulous people visiting the Prosthodontics Department were surveyed.

Subjects and Methods:

A questionnaire (based on previous studies) to test the emotional reactions to tooth loss and Nine Item-Patient Health Questionnaire to test for depression were used.

Statistical Analysis Used:

The data were analyzed using the Chi-square (χ²) test with the help of SPSS v. 18.0 (IBM Corp., Armonk, NY, USA).

Results:

Totally, 100 out of 147 edentulous people returned the questionnaire of which 58% experienced difficulties in accepting tooth loss and 37% felt unprepared for its effects. Those with difficulties accepting tooth loss had a greater effect on self esteem and social life, had more reservation about discussing tooth loss and was more likely to experience depression. Both groups were satisfied with dentures, had no problem meeting their friends or partners without dentures and leaving out dentures at night.

Conclusion:

About 58% of edentulous people had difficulties accepting tooth loss, which was unrelated to denture satisfaction. Respondents appeared to be restricted in social activities mainly due to functional limitations. Those with difficulties accepting tooth loss were more likely to experience depression.

Prevalence of denture-related oral lesions among patients attending College of Dentistry, University of Dammam: A clinico-pathological study

Background:

Heterogeneous groups of oral lesions are likely to develop among denture wearers. The objectives of this study were to determine the exact prevalence of oral lesions among denture wearers attending the clinics of the College of Dentistry, University of Dammam.

Materials and Methods:

All denture wearers attending the dental clinics in the period between January 2012 and April 2013 were included in this study. Of the total 210 patients, 166 (79%) were males and 44 (21%) were females. Comprehensive oral examination was performed for all patients. Any denture-induced lesion was biopsied. Data collected were analyzed using SPSS program.

Results:

Oral lesions were found in 20.5% of the cases under study (43 out of the total 210 denture wearers). Denture-induced fibrous hyperplasia was the most common type of lesion detected (41.9%). A significant correlation (P = 0.004) was found between the type of denture and oral lesions in this study.

Conclusion:

The prevalence of denture-induced oral lesions was found to differ significantly from that reported in other studies. The diversity of these lesions among different studies depends on the quality and materials of dentures delivered, the techniques used, and the methods of patients’ instructions adopted.

Microbial contamination of removable dental prosthesis at different interval of usage: An in vitro study

Background:

Loss of teeth affects the individual's health. Many factors determine the need to wear a removable dental prosthesis. Due to nature of design, age and lack of awareness, prosthesis often are neglected to maintain in an aseptic condition leading to microbial contamination. This provided an impetus for the present study with the aim of determining the microbial contamination of removable dental prosthesis.

Methodology:

Total, 45 patients wearing removable dental prosthesis were randomly selected. Patients were divided into three groups as per duration of usage since 1 month, 6 month and ≥1 year. Sterile cotton swab moistened with phosphate buffer saline (PBS) was used to collect swab from the fitting areas of prosthesis. Swab samples was inserted immediately into the sterile tube containing 1 ml of PBS solution, 10 μl PBS is inoculated on the blood agar and MacConkey agar plates using spread plate technique. Samples were cultured and incubated at 37°C for 48 h. Calibrated microbiologist isolated, identified and counted microorganisms using colony counter. Depending on the nature of data, statistical analysis was done applying Kruskal–Wallis test, Mann–Whitney U-test and Chi-square test.

Result:

Streptococcus species and Staphylococcus aureus were the common microorganisms isolated in all three groups and was statistically significant at P <0.05. Candida albicans, Diptheroid, Escherichia coli, Micrococcus species were isolated from Group II and Group III.

Conclusion:

There is a linear increase in microbial contamination of removable dental prosthesis as the duration of usage increases and might increase the susceptibility of individuals' to many diseases.

Can shielded brackets reduce mucosa alteration and increase comfort perception in orthodontic patients in the first 3 days of treatment? A single-blind randomized controlled trial

INTRODUCTION

Orthodontic patients can experience pain and discomfort on the oral mucosa from trauma caused by friction with the brackets and the wires. In this split-mouth design, single-blind randomized controlled trial, we aimed to investigate whether brackets with a self-snapping customized plastic shield would induce less mucosa alteration and discomfort than those without the shield.

METHODS

The overall sample comprised 42 patients (22 female, 20 male) from a government-funded orthodontic practice, with a mean age of 16.7 years. Eligibility criteria included, among others, no history of mouth ulcers or systemic diseases. Customized shields for the maxillary and mandibular brackets were fabricated and inserted on one side of the mouth. The null hypothesis was that bracket shielding would have no advantage. The primary outcomes were mucosal and discomfort assessments. As the secondary outcome, the numbers of spontaneous detachments of the shields were reported. Treatment allocation was mainly implemented using a random number table for selection of the intervention side. Only the raters in charge of assessing the oral mucosa were blinded to the side of the mouth where the shields had been placed. The mucosa was assessed by 3 calibrated raters at the following time points: immediately before bracket placement (baseline assessment, T0), 3 days after delivering the shields (direct assessment of intervention, T1), and 4 days after removal of the shields (indirect assessment of intervention, T2). The raters used a newly devised yardstick in which the higher the score, the more severe the alteration. Discomfort was assessed at T1 and T2 using a visual analog scale. The Mann-Whitney U test was performed at the 5% level of significance.

RESULTS

Of 60 patients, 42 were eligible, and 35 were randomly selected to have one side of the mouth receive the intervention. Two patients discontinued the intervention at T1, and 5 stopped at T2. Seven additional patients were recruited and completed all time points. Thus, 42 patients participated at T0, 40 at T1, and 35 at T2. Thirty-five patients participated at all time points. At T1, no statistically significant difference in terms of mucosa alteration was observed between the 2 sides (median of all differences [MD], 0.0; 95% CI, 0.0-1.0; P = 0.11). The same occurred at T2 (MD, 0.0; 95% CI, 0.0-0.0; P = 1.00). The comfort level was statistically higher at T1 on the shielded side (MD, 14.0; 95% CI, 1.0-36.0; P = 0.04), whereas no difference was observed at T2 (MD, 0.0; 95% CI, 0.0-1.0, P = 0.81). No serious harm was observed.

CONCLUSIONS

The customized bracket shields were effective in reducing discomfort during the first 3 days of orthodontic treatment despite no significant difference in terms of visible mucosa alteration.

REGISTRATION

This trial was not registered.

PROTOCOL

The protocol was not published before trial commencement.

FUNDING

Expenses for the fabrication of the shields were covered by the main author (L.P.B.P.). Orthodontic materials were from the Center for Dental Specialties in Cajazeiras, Brazil.

Shortcomings of prosthodontic rehabilitation of patients living in long-term care facilities

Removable dentures are a non-invasive, cost-effective prosthodontic solution for the reduced dentition. Their intended purpose is the rehabilitation of harmonious oral function and aesthetics on a long-term basis. The prevalence of removable dentures among patients of advanced age is high and the quality of the dentures is often poor. The aim of this study was to find the most important shortcomings of removable dentures and address the main targets for improving the quality of prosthodontic rehabilitation. The records from dental check-ups in Austrian residential homes were analysed retrospectively. Dental anamnesis questionnaires and data from the clinical examinations of 105 denture wearers were analysed. The functional condition and retention of 192 dentures had been assessed, as well as the impact of the dentures on the intra-oral tissues. Insufficient denture retention was very common, particularly in the lower jaw (56·0%). Problems with the masticatory function were reported by 26.7% of the denture wearers, 11·4% were dissatisfied with the denture aesthetics, and 4·8% had difficulties with phonetics. Traumatic ulcers were found in 18·1%. Cracks, broken pieces (6·3%) or missing denture teeth (2·1%) were rare. It may be assumed that the findings of the present study also apply to a great percentage of community-dwelling seniors. The most important issues in prosthodontic rehabilitation with removable dentures are denture retention and masticatory function. Regular dental check-ups, denture adjustment and, when necessary, relining can maintain the primary denture quality and prevent damages of the oral tissues caused by ill-fitting dentures.

Dental demographics and metrics of oral diseases in the ageing Australian population

One of the biggest challenges currently facing the dental profession in Australia is the provision of quality and timely dental care to the elderly. Adults aged 65+ years are an exponentially growing section of the community with rapidly changing dental needs, thanks in part to improvements in oral health over the past 60 years that have resulted in a dramatically decreased rate of edentulism and subsequently an increased number of teeth present. This is a challenge not only for the public dental services, but also public health policy makers, private dental practitioners, professional organizations and dental education providers. It is an issue that crosses a range of dental care providers, not only dentists but also dental prosthetists and dental hygienists, whose role in the provision of dental services has been slowly growing in Australia. Furthermore, with evidence of links between oral and systemic health, this issue has significant impacts for the broader health system.

Photodynamic inactivation of virulence factors of Candida strains isolated from patients with denture stomatitis

Candida species are major microorganisms isolated in denture stomatitis (DS), an inflammatory process of the mucosa underlying removable dental prostheses, and express a variety of virulence factors that can increase their pathogenicity. The potential of Photodynamic inactivation (PDI) in planktonic culture, biofilms and virulence factors of Candida strains was evaluated. A total of 48 clinical Candida isolates from individuals wearing removable maxillary prostheses with DS were included in the study. The effects of erythrosine (ER, 200 μM) and a green LED (λ 532 ± 10 nm, 237 mW/cm(2) and 42.63 J/cm(2)) in a planktonic culture were evaluated. The effect of the addition of ER at a concentration of 400 μM together with a green LED was evaluated in biofilms. The virulence factors of all of the Candida strains were evaluated before and after the PDI process in cells derived from biofilm and planktonic assays. All of the Candida species were susceptible to ER and green LED. However, the biofilm structures were more resistant to PDI than the planktonic cultures. PDI also promoted slight reductions in most of the virulence factors of C. albicans and some of the Candida tropicalis strains. These results suggest that the addition of PDI is effective for reducing yeasts and may also reduce the virulence of certain Candida species and decrease their pathogenicity.

Anti-fungal resistance in candida isolated from oral and diaper rash candidiasis in neonates

The purpose of the present study is to evaluate the sensitivity of Candida species isolated from oral candidiasis and diaper dermatitis infections in children. The children referring to private and public clinics in Ilam, Iran were exmined for oral candidiasis and diaper dermatitis. In this study, 248 oral candidiasis and diaper dermatitis samples were collected and cultured.Candida species were identified by using standard methods. Resistance and sensitivity to amphotericin B, nystatin, ketoconazole, fluconazole, itraconazole, clotrimazole, and posaconazole were determined using the CLSI M44-A standard disk diffusion method. From the 248 studied samples, 149 were positive for Candida, among which the Candida albicans was the most prevalent (64.4%). The resistance of different Candida species to nystatin, itraconazole, fluconazole, ketoconazole, clotrimazole, voriconazole, and posaconazole were 4, 43, 34.2, 34.9, 21.5, 6, and 6.7%, respectively. No resistance to amphotericin B was observed. Considering rather low resistance to nystatin, this drug is the best choice for oral candidiasis and diaper dermatitis.

A survey assessing modes of maintaining denture hygiene among elderly patients

Objective:

To determine the denture hygiene habits in complete denture wearers.

Materials and Methods:

In this study, a self-administered structured questionnaire was developed to know the attitude of the patients from the Department of Prosthodontics regarding denture hygiene. The study sample consisted of totally 500 subjects, which included 284 (56.8%) males and 216 (43.2%) females. Data were analyzed using SPSS version 15.0 with Chi-square (χ²) test at P < 0.05.

Results:

Nearly half of the subjects cleaned their dentures daily once. Participants from the younger age group and who had been wearing dentures since 2 years maintained better frequency of cleaning. The majority of these subjects used water and brush for denture cleansing. After seeing the condition, more than half of the dentures were rated as poor (60%). There was significant difference between all the groups on comparison (P = 0.001).

Conclusion:

Poor condition of complete dentures seen in the population is mainly due to irregular cleansing habits and also less usage of cleansing solutions. Dentists should give proper instructions regarding maintenance of denture hygiene.

Denture hygiene habits among elderly patients wearing complete dentures

OBJECTIVE

To determine the denture hygiene habits in complete denture patients according to their age and time of dentures.

METHODS

In this study a self administered structured was developed to know the attitude of the patients regarding denture hygiene in the department of Prosthodontics. The total study sample consisted of 230 subjects including 124 (53.9%) males and 106 (46.1%) females. Data was analyzed using SPSS version 15.0 with chi-square test at p-value <0.05.

RESULTS

Nearly half of the subjects clean their dentures daily once. Participants from the younger age group and who had been wearing dentures since 2 years maintain better frequency of cleaning. The majority of these subjects used water and brush for denture cleansing. After seeing the condition, half of the dentures were rated as good 50.3%, followed by fair and poor as 29.5 and 20.2% respectively.

CLINICAL SIGNIFICANCE

Poor condition of complete dentures seen in the population is mainly due to irregularly cleansing habits and also less usage of cleansing solutions. Dentists should give proper instructions regarding maintenance of denture hygiene.

Denture polymers with antimicrobial properties: a review of the development and current status of anionic poly(methyl methacrylate) polymers

The denture base polymer poly(methyl methacrylate) (PMMA) is highly susceptible for microbial colonization resulting in denture-associated infections. Over the years research has focused on ways to modify the PMMA properties via surface and chemical modification. These studies led to the development of new denture polymers that include anionic PMMA polymers. The new anionic polymers presented the possibility of compromising the physical and mechanical properties required for denture fabrication. These obstacles were overcome by generating anionic PMMA polymers with physical and mechanical properties suitable for denture fabrication. A large body of literature is available on the anionic PMMA polymers, their antimicrobial properties and their potential for the commercial and clinical application as dental biomaterials. This article describes a review and evaluation of the anionic PMMA polymers for their suitability to serve as denture base polymers, their antimicrobial properties, their efficacy to prevent denture-induced infection and their safety in the oral environment.

Development of a new model system to study microbial colonization on dentures

PURPOSE

Dentures are often colonized with a variety of microorganisms, including Candida albicans, that contribute to denture stomatitis. Several in vitro models have been previously established to study denture-related microbial colonization and evaluate treatment efficacy of denture cleansers; however, those models typically fail to appreciate the complex topology and heterogeneity of denture surfaces and lack effective ways to accurately measure microbial colonization. The purpose of this study was to study microbial colonization with a new model system based on real dentures, to more realistically mimic in vivo conditions.

MATERIALS AND METHODS

Scanning electron microscopy was used to observe topological structures among surfaces from different parts of the denture. Employing C. albicans as a model microorganism, we established microbial colonization on different denture surfaces. Moreover, we applied a modified MTT (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) colorimetric assay to quantify C. albicans colonization on dentures without the necessity of biofilm removal and to evaluate treatment efficacy of denture cleansers.

RESULTS

There were significant variations in topological structures among surfaces from different parts of the denture, with the unpolished side having the highest amounts of indentations and pores. The distinct denture surfaces support microbial colonization differently, with the unpolished side containing the highest level of microbial colonization and biofilm formation. Furthermore, the modified MTT colorimetric assay proved to be an accurate assay to measure biofilm formation on dentures and evaluate treatment efficacy of denture cleansers.

CONCLUSION

This new denture model system in conjunction with the MTT colorimetric assay is a valuable tool to study denture-related microbiology and treatment approaches.

Effectiveness of coating acrylic resin dentures on preventing Candida adhesion

PURPOSE

The aim of this study was to prevent the adhesion of C. albicans on acrylic resin dentures by modifying their surfaces.

MATERIALS AND METHODS

Ninety acrylic resin plates were divided into three groups. Group I: conventionally processed acrylic resin plates. Group II: plates painted with 2-Octyl Cyanoacrylate adhesive. Group III: plates painted with Adper Single Bond Adhesive. All specimens were immersed separately in containers filled with artificial saliva that contained C. albicans and then incubated for 11 days at 37°C. Three methods of evaluation were used to count the adhered Candida: direct culture, slide count, and serial dilutions.

RESULTS

C. albicans in 1/10, 1/10², and 1/10³ dilutions showed overgrowth in group I, while overgrowth was noted only with 1/10 dilution in group III. For group III, mean colony numbers of 123, 22, 3.4, and 0 were found for the 1/10², 1/10³, 1/10⁴, and 1/10⁵ dilutions, respectively. Regarding the slide counts, group I showed a mean fungal count of 166 compared to 40 for group III with 1/10 dilution, 21 compared to 9 with 1/10³ dilution, 8.6 compared to 0.7 with 1/10³ dilution, and 1.2 compared to 0 with 1/10⁴ dilution. No plates in group II showed any candidal colonies regardless of the method of evaluation (0%). These differences were statistically significant (p < 0.0001).

CONCLUSION

Coating the acrylic resin dentures with Adper Single Bond Adhesive was effective in reducing C. albicans adhesion to dentures, while coating with 2-Octyl Cyanoacrylate adhesive completely inhibited such adhesion.

Occurrence of Candida species colonization in a population of denture-wearing immigrants

Infection of the oral cavity and dentures by Candida species are frequent in denture wearers. C. albicans is the most common pathogen; however, other emerging Candida species are also responsible for this condition. Few data are available about the occurrence of Candida species in the oral cavities of denture-wearing immigrants to Italy. In this study, we compare the Candida species found in the oral mucosa and on dentures from a population of denture wearing immigrants to Italy to a matched Italian group. Oral swabs were collected from dentures and the underlying mucosa of patients enrolled in the study and were then cultured to test for the presence of Candida species in each sample. Out of 168 patients enrolled (73 Italians and 95 immigrants), 51 Italians (69.8 percent) and 75 immigrants (78.9 percent) tested positive for the presence of Candida. Candida albicans was the most frequently observed species overall; however, we found a higher occurrence of C. glabrata among immigrants than among Italians. In addition, immigrants displayed a higher incidence of Candida – associated stomatitis and a lower mean age than Candida-positive individuals from the Italian group. Immigrants are more prone to longer colonization of the oral mucosa and dentures by Candida. In these patients, dentures must be checked periodically to prevent the presence of Candida.

Prevalence of oral mucosal lesions in a group of Iranian dependent elderly complete denture wearers

AIM

Oral mucosal lesions are frequently observed in institutionalized elderly patients more than other age groups. The aim of this study was to determine the prevalence of epulis fissuratum and denture stomatitis and their associated causes in dependent elderly complete denture wearers.

MATERIALS AND METHODS

This study was conducted in dependent elderly complete denture's wearers living in four randomly selected nursing homes located in Tehran. Associated factors such as gender, age, use of medication, site of nursing home, denture quality and denture-wearing habit were studied.

RESULTS

Overall, 674 patients were examined; 201 had complete denture. The prevalence of denture stomatitis was 36%. There was significant relationship among the prevalence of denture stomatitis with gender and denture wearing period (p < 0.05). The prevalence of epulis fissuratum was 16.4%. There was significant relationship among the prevalence of epulis fissuratum with gender, denture quality and denture wearing habit (p < 0.05).

CONCLUSION

In this particular dependent age group, the prevalence of oral mucosal lesions is high and the mentioned associated factors should be noticed.

CLINICAL SIGNIFICANCE

Dependent elderly complete denture wearers need more support and motivation for reducing the prevalence of these particular denture-associated oral mucosal lesions.

Does the presence of anterior mandibular teeth increase the incidence of denture stomatitis?

PURPOSE

To compare the frequency of denture stomatitis (DS) under maxillary complete dentures (CDs) in patients with opposing mandibular distal extension removable partial dentures (RPDs) and CDs.

MATERIALS AND METHODS

Participants included 365 maxillary CD wearers (241 women, mean age 70.5 ± 13.2 years; 124 men, mean age 71.5 ± 10.4 years) from 7 rest homes in Istanbul. A total of 268 had mandibular CDs; 97 had mandibular distal extension RPDs. Two independent, calibrated examiners performed oral examinations. Presence of maxillary denture-related stomatitis and the effect of risk factors on DS were evaluated and recorded.

RESULTS

The frequency of palatal DS (Newton I-III) was 45.1% (n = 121) in the mandibular CD group and 49.5% (n = 48) in the mandibular distal extension RPD group, a statistically insignificant difference (p= 0.4). Factors significantly associated with palatal DS were maxillary denture age (p= 0.02), reduced occlusal vertical dimension (p= 0.04), and nocturnal denture wear (p= 0.03).

CONCLUSION

In this study, DS beneath maxillary CDs did not differ between mandibular distal extension RPD and CD wearers. The presence of mandibular anterior teeth did not influence the occurrence of palatal DS.