The human oral cavity can support approximately 700
different species of microorganism, including 20 Candida species.(1,2) Previous
studies have shown a high prevalence of Candida spp. in the oral cavities of
patients with denture stomatitis (94%) and healthy people who wear dentures
Candida can be present in healthy hosts and is not
considered harmful unless certain conditions are met, creating opportunities
for virulence that causes candidiasis.(4) Oral candida was reportedly found in 34.4% of
healthy subjects without symptoms and in 54.7% of hospitalized subjects.(5) However, candidal infections are
considered a major problem globally, particularly for people with
Different types of Candida that are associated with
both clinical and nonclinical conditions can be present on the surface of the
oral cavity, such as C. albicans, C. tropicalis, C. glabrata, C. parapsilosis,
C. stellatoidea, C. krusei and C. kefyr, but only a few cause candidiasis.(13–17) Specifically, C. albicans is commonly
isolated from the oral cavity.
Diabetes mellitus is a chronic metabolic disorder
that is becoming one of the most common chronic diseases worldwide. The recent increase
in the number of adults with diabetes is particularly surprising; an estimated
300 million adults are expected to have diabetes by the year 2025.(18) In Jordan, there has been a significant increase
in the prevalence of type II diabetes mellitus during the last 10 years, with 31.5%
of the population affected.(19) Metformin and insulin are the most common
treatment for type II diabetes (20).
Patients with diabetes have a higher prevalence of
candida than patients without diabetes,(21–23) and clinical manifestations of candida infection
occur more frequently and severely in patients with diabetes than patients
without diabetes.(24–27) C. albicans is one of the most common species
isolated from patients with diabetes, with a prevalence of up to 80%,(21,24,25,28) and is the most common virulent fungal pathogen of
the Candida species.(29) Changing in salivary glucose levels in patients
with diabetes can causes an alteration of yeast growth. (30)
However, the results are controversial based on
contradictory results in other studies.(24,31–33)
The prevalence of Candida infection is also higher
in people who use dentures, especially in patients with diabetes.(27,28,34,35) Owing to the increase in diabetes within the
population, especially in the elderly, there has been an increased need for
dentures. As the use of dentures is becoming more common, this could increase
the risk of candida infection in this population, owing to the effects in the
oral cavity and altered oral mucosa in addition to systemic complications.(21,26–28,35)
The aim of present study was to investigate the
prevalence of C. albicans in the oral cavity among type II diabetic patients on
insulin with metformin vs. those on metformin only with or without an acrylic
plate. The effect of the level of oral hygiene on candida growth was also
Does Diabetic type II patients on Metformin and
insulin, wearing an upper denture associated with higher prevalence of candidiasis?
Does Patients with poor oral hygiene had higher prevalence
The present study was approved by the Royal Medical
Services ethics committee. All of the participants provided verbal consent and
permission for the procedures.
The study was conducted in multiple diabetes care
clinics in the Royal Medical Services (RMS), Ministry of Health (MOH) and private
sector, on patients who had been diagnosed with type II diabetes mellitus at least
1 year previously and were on medication protocol with either Metformin only or
Insulin with Metformin and follow the protocols for Diabetes type II treatment
for each clinic. Patients who were currently taking or who had been administered
antibiotics, antifungal medications, steroids, or immunosuppressive drugs in
the past 3 months were excluded. All patients who used removable denture
complete or partial were excluded.
A list of case numbers was randomly generated from
1 to 50 for male patients and 1 to 50 for female patients. Half of each list
(25) was randomly assigned to be fitted with an acrylic plate (test group) and the
rest formed the control group.
Personal information (name, age, sex) and the
medical history (medication use) of the patients were recorded by a registered nurse.
A case number was assigned to each patient.
An alginate impression of the upper arch was taken from
patients in the test group and sent to the lab. An upper acrylic plate was constructed
for each patient, consisting of an acrylic plate covering the upper denture,
clasps and Adams clasps for molars and premolars.We asked the patients to wear the plate all day,
and to remove it at night. They were given instructions on how to clean it regularly.
The dental history, oral hygiene of the patient and
acrylic plate were graded as good, average, or poor based on the dentist’s report.
Tissue samples were collected from the upper palate
of patients without an acrylic plate and from the tissue-bearing area of the
upper acrylic plate by scraping with a sterile swab. The swabs were processed
for microbiological examination by immersing them in 5 mL sterile 0.9%
physiological saline. This was vortexed for 1 min to disperse the adhering
bacteria. A loopful of the suspension was plated on Sabouraud’s dextrose (SD)
agar containing gentamycin (2 mg/dL) and chloramphenicol (5 mg/dL) and
incubated for 48 h at 37°C. which produce creamy white pasty ,followed by using
CHROMagar for identification of candida albicans which show light green colour.
All patients underwent a glycohaemoglobin (HbA1c)
Data were entered and coded using SPSS version 17.0
(Chicago, IL, USA). Values are reported as frequencies and mean ± standard
deviation. Pearson’s r was used to test the correlations between variables. P
values <0.05 were considered statistically significant.
The sample consisted of 100 (50 male, 50 female) participants
aged 20–68 years (mean, 49.1 ± 10.7 years; men, 47.5 ± 8.4 years; women, 50.6 ±
C. albicans was isolated from 32 (32%) patients: 21
men, 11 women; 20 patients on metformin only, 12 patients on insulin with
metformin; 12 patients with poor oral hygiene, 9 patients with average oral
hygiene, and one patient with good oral hygiene. The remaining 68 (68%)
patients tested negative for C. albicans (Table 1).
The mean HbA1c was
8.3 ± 1.5 (male 8.4 ± 1.6, female 8.2 ± 1.4). Candida-positive patients
had a mean HbA1c of 8.3 ± 1.4 and Candida-negative patients had a mean
HbA1c of 8.4 ± 1.6. The mean HbA1c in patients
on metformin only was 8.3 ±1.0 and in patients on insulin with metformin it was
8.3 ±1.8. The mean HbA1c in the control group was 8.4 ± 1.5 and in the test
group with the acrylic plate it was 8.2 ± 1.5.
The data revealed
that there was no significant difference in prevalence of Candida according to age,
HbA1c test result, type of medication or presence of acrylic plate (p = 0.84, 0.73, 0.09 and 0.40 respectively),
but it was significantly affected by gender and oral hygiene (p = 0.03 and 0.00
respectively).The prevalence of Candida spp. was higher in males than in females
(Fig. 1).The prevalence of C. albicans was higher in patients on metformin only
than in patients on insulin with metformin (Fig. 2).The prevalence of C. albicans
was higher in the test group with the acrylic plate than in the control group (Fig.
3). Poor Oral hygiene had direct proportion influence on the prevalence of C. albicans in both
groups (Fig. 4). Males had poorer oral hygiene than females. Oral hygiene was
rated as poor in 32% of the participants (C. albicans positive 34.6%), average in
26% of the participants (C. albicans positive 26.0%), and good in 42% of the
participants (C. albicans positive 2.4%) (Table I).
Table I Candida albicans: Gender, Treatment Regime, Use of
Acrylic Plate and Oral Hygiene.
Age P value = 0.84, HbA1c test P value = 0.73
In the present study, 32 of the 100 (32%) patients tested
positive for C. albicans in their oral cavity, a lower prevalence than in previous
studies testing diabetic patients but higher than in healthy patients (p <
0.05)(36–38). There was a significantly higher prevalence of
colonization in males compared with females, unlike in Kadir et al. (33) and Sahin et al. (32), who found no significant effect of age or sex on
the presence of C. albicans (p > 0.05). Diabetes mellitus affects the
composition and amount of saliva, which influences the microorganism population
in the oral cavity. Increased salivary glucose levels in patients with diabetes
causes yeast growth owing to an increased number of candida receptors. (30)Similarly, reducing salivary flow also increases
colonization by candida and plays a role in candidiasis.(33) Furthermore, immunosuppression can
occur with diabetes mellitus, which could increase the susceptibility to oral
infections with Candida spp.(6,7,21,22,24,31–33)
Regarding the association between C. albicans colonization
and the degree of diabetic control, as indicated by HbA1c, there was no
difference in control between patients who tested positive and those who tested
negative for C. albicans. The mean Hba1c was 8.3 ±1.4 for C. albicans negative
and 8.4 ±1.6 for C. albicans positive subjects.
Regarding treatment regime patients who only used metformin
had a higher prevalence of C. albicans (40%) than patients who were using
insulin with metformin (24%), but the difference was not significant (P=0.09).
patients on Metformin had higher glucose level in saliva due to difference in
control potency between Insulin and Metformin.(39)
The presence of an acrylic plate decreases the
salivary pH and flow rate and impedes the mechanical cleaning of the soft
tissue of the oral cavity.(15) This increases infective virulence and aggravates
previously existing infective conditions. The use of an acrylic plate changes
the physiology and normal flora of the palate. The tissue in contact with the surface
of the acrylic plate is disturbed less often, which favours the colonization of
microbes, especially acidogenic bacteria and Candida.(40) Wearing an acrylic plate induces plaque formation,
favouring an increased population of potentially pathogenic bacteria and
Candida spp.(41,42) The current investigation is consistent with
previous studies that showed an increase in Candida colonization in a group with
an acrylic plate (36%) compared to the control group (28%) (28,43), although the difference was not significant.
In the present study, 34.6% of patients with poor
oral hygiene had candida, 26% of patients with average oral hygiene had
candida, and 2.4% of patients with good oral hygiene had candida; these rates are
higher than in the normal population but lower than those reported by Muzurovic
et al., who reported Candida spp. in 83.4% of patients with teeth and poor oral
hygiene; the most frequently isolated type was C. albicans.(44)
Treatment Protocol for Treating Diabetes type II
using Insulin with Metformin or Metformin only and the use of an acrylic plate
had no effect on increasing or decreasing the candida albicans prevalence. On
the other hand the level of oral hygiene had more influence on the prevalence
of C. albicans, with males being more susceptible than females. HbA1c test cannot be used as an indication of the possibility
of colonization by C. albicans among type II diabetic patients, because the
level of control of glucose found in current study to be not the major factor.
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