Publications by authors named "Preethi Balan"

14 Publications

  • Page 1 of 1

Role of the oral microbiome, metabolic pathways, and novel diagnostic tools in intra-oral halitosis: a comprehensive update.

Crit Rev Microbiol 2021 Mar 3:1-17. Epub 2021 Mar 3.

Oral Health ACP, Duke NUS Medical School, Singapore, Singapore.

Halitosis or oral malodor is one of the most common reasons for the patients' visit to the dental clinic, ranking behind only dental caries and periodontitis. In the present times, where social and professional communications are becoming unavoidable, halitosis has become a concern of growing importance. Oral malodor mostly develops due to the putrefaction of substrates by the indigenous bacterial populations. Although culture-based studies have provided adequate information on halitosis, the high throughput omics technologies have amplified the resolution at which oral microbial community can be examined and has led to the detection of a broader range of taxa associated with intra-oral halitosis (IOH). These microorganisms are regulated by the interactions of their ecological processes. Thus to develop effective treatment strategies, it is important to understand the microbial basis of halitosis. In the current review, we provide an update on IOH in context to the role of the oral microbiome, metabolic pathways involved, and novel diagnostic tools, including breathomics. Understanding oral microbiota associated with halitosis from a broader ecological perspective can provide novel insights into one's oral and systemic health. Such information can pave the way for the emergence of diagnostic tools that can revolutionize the early detection of halitosis and various associated medical conditions.
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http://dx.doi.org/10.1080/1040841X.2021.1888867DOI Listing
March 2021

Efficacy of commercial mouth-rinses on SARS-CoV-2 viral load in saliva: randomized control trial in Singapore.

Infection 2021 Apr 14;49(2):305-311. Epub 2020 Dec 14.

Department of Infectious Diseases, Singapore General Hospital, Singapore, Singapore.

Purpose: One of the key approaches to minimize the risk of COVID-19 transmission would be to reduce the titres of SARS-CoV-2 in the saliva of infected COVID-19 patients. This is particularly important in high-risk procedures like dental treatment. The present randomized control trial evaluated the efficacy of three commercial mouth-rinse viz. povidone-iodine (PI), chlorhexidine gluconate (CHX) and cetylpyridinium chloride (CPC), in reducing the salivary SARS-CoV-2 viral load in COVID-19 patients compared with water.

Methods: A total of 36 SARS-CoV-2-positive patients were recruited, of which 16 patients were randomly assigned to four groups-PI group (n = 4), CHX group (n = 6), CPC group (n = 4) and water as control group (n = 2). Saliva samples were collected from all patients at baseline and at 5 min, 3 h and 6 h post-application of mouth-rinses/water. The samples were subjected to SARS-CoV-2 RT-PCR analysis.

Results: Comparison of salivary Ct values of patients within each group of PI, CHX, CPC and water at 5 min, 3 h and 6 h time points did not show any significant differences. However, when the Ct value fold change of each of the mouth-rinse group patients were compared with the fold change of water group patients at the respective time points, a significant increase was observed in the CPC group patients at 5 min and 6 h and in the PI group patients at 6 h.

Conclusion: The effect of decreasing salivary load with CPC and PI mouth-rinsing was observed to be sustained at 6 h time point. Within the limitation of the current study, as number of the samples analyzed, the use of CPC and PI formulated that commercial mouth-rinses may be useful as a pre-procedural rinse to help reduce the transmission of COVID-19. ISRCTN (ISRCTN95933274), 09/09/20, retrospectively registered.
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http://dx.doi.org/10.1007/s15010-020-01563-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7734110PMC
April 2021

Inhibitory effects of xylitol and sorbitol on Streptococcus mutans and Candida albicans biofilms are repressed by the presence of sucrose.

Arch Oral Biol 2020 Nov 29;119:104886. Epub 2020 Aug 29.

Singapore Oral Microbiomics Initiative, National Dental Research Institute Singapore (NDRIS), National Dental Centre Singapore, SingHealth Duke NUS Medical School, 5 Second Hospital Avenue, Singapore. Electronic address:

Objective: Among the preventive and therapeutic options available for dental caries, sugar alcohols (xylitol and sorbitol) have been widely promoted as oral healthcare products due to its perceived anticariogenic effect. However, the therapeutic efficacy of these sugar alcohols against Streptococcus mutans and Candida albicans in a sucrose supplemented environment, as found in disease-prone conditions in the oral cavity, has not been adequately investigated.

Methods: Single and mixed-species biofilm formation was evaluated in medium with different concentrations of xylitol, sorbitol with or without sucrose supplementation. Biofilm quantification methods such as crystal violet assay, XTT assay, CFU counting complemented with confocal and electron microscopic techniques were used.

Results: Under sucrose-free conditions, xylitol and sorbitol demonstrated a significant dose-dependent inhibitory effect on S. mutans biofilms, whereas inhibitory effect on C. albicans biofilm was weak. The presence of 1 % sucrose in the environment diminished the inhibitory effect of both xylitol and sorbitol on S. mutans and C. albicans mono-species biofilms. Sucrose supplementation on pre-formed S. mutans biofilms also reduced the inhibitory effect of xylitol. Xylitol and sorbitol presence reduced mixed-species biofilm formation and altered the biofilm architecture and glucan production. However, sucrose supplementation reduced the inhibitory effect of sugar alcohols and enhanced the mixed-species biofilm formation.

Conclusions: Xylitol and sorbitol exerts an inhibitory effect on S. mutans and C. albicans biofilm formation and this inhibitory effect is repressed by the presence of sucrose.
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http://dx.doi.org/10.1016/j.archoralbio.2020.104886DOI Listing
November 2020

Oral microbiome-systemic link studies: perspectives on current limitations and future artificial intelligence-based approaches.

Crit Rev Microbiol 2020 May 21;46(3):288-299. Epub 2020 May 21.

Department of Preventive Dentistry, Academic Centre for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.

In the past decade, there has been a tremendous increase in studies on the link between oral microbiome and systemic diseases. However, variations in study design and confounding variables across studies often lead to inconsistent observations. In this narrative review, we have discussed the potential influence of study design and confounding variables on the current sequencing-based oral microbiome-systemic disease link studies. The current limitations of oral microbiome-systemic link studies on type 2 diabetes mellitus, rheumatoid arthritis, pregnancy, atherosclerosis, and pancreatic cancer are discussed in this review, followed by our perspective on how artificial intelligence (AI), particularly machine learning and deep learning approaches, can be employed for predicting systemic disease and host metadata from the oral microbiome. The application of AI for predicting systemic disease as well as host metadata requires the establishment of a global database repository with microbiome sequences and annotated host metadata. However, this task requires collective efforts from researchers working in the field of oral microbiome to establish more comprehensive datasets with appropriate host metadata. Development of AI-based models by incorporating consistent host metadata will allow prediction of systemic diseases with higher accuracies, bringing considerable clinical benefits.
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http://dx.doi.org/10.1080/1040841X.2020.1766414DOI Listing
May 2020

Keystone Species in Pregnancy Gingivitis: A Snapshot of Oral Microbiome During Pregnancy and Postpartum Period.

Front Microbiol 2018 9;9:2360. Epub 2018 Oct 9.

Discipline of Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore, Singapore.

It is well known that pregnancy is under the constant influence of hormonal, metabolic and immunological factors and this may impact the oral microbiota toward pregnancy gingivitis. However, it is still not clear how the oral microbial dysbiosis can modulate oral diseases as oral microbiome during pregnancy is very poorly characterized. In addition, the recent revelation that placental microbiome is akin to oral microbiome further potentiates the importance of oral dysbiosis in adverse pregnancy outcomes. Hence, leveraging on the 16S rRNA gene sequencing technology, we present a snapshot of the variations in the oral microbial composition with the progression of pregnancy and in the postpartum period and its association with pregnancy gingivitis. Despite the stability of oral microbial diversity during pregnancy and postpartum period, we observed that the microbiome makes a pathogenic shift during pregnancy and reverts back to a healthy microbiome during the postpartum period. Co-occurrence network analysis provided a mechanistic explanation of the pathogenicity of the microbiome during pregnancy and predicted taxa at hubs of interaction. Targeting the taxa which form the ecological guilds in the underlying microbiome would help to modulate the microbial pathogenicity during pregnancy, thereby alleviating risk for oral diseases and adverse pregnancy outcomes. Our study has also uncovered the possibility of novel species in subgingival plaque and saliva as the key players in the causation of pregnancy gingivitis. The keystone species hold the potential to open up avenues for designing microbiome modulation strategies to improve host health during pregnancy.
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http://dx.doi.org/10.3389/fmicb.2018.02360DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6189292PMC
October 2018

Oral Health in Pregnant Chinese Women in Singapore: A Call to Go beyond the Traditional Clinical Care.

Healthcare (Basel) 2018 Jul 9;6(3). Epub 2018 Jul 9.

Discipline of Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore 119083, Singapore.

Objective: To examine the correlations among oral health knowledge, attitude, practices and oral disease among pregnant Chinese women in Singapore. : A descriptive correlational study was conducted in pregnant Chinese women in Singapore. A questionnaire was used to collect data of oral health knowledge, attitude and practices. Plaque index scores were used to assess the oral health of subjects. : A total of 82 pregnant women participated in the study, out of whom 38% showed adequate oral health knowledge, nearly half of them achieved adequate and oral health attitude and practice scores while 34% had good Plaque index scores. The lower income group had higher experience of self-reported dental problems during pregnancy than those in the higher income group ( = 0.03). There were significant positive correlations between scores of oral health practice, attitude and oral health knowledge levels. The plaque index scores negatively correlated with the oral health practice scores ( = 0.02). : Our findings provided evidence that oral health knowledge, attitude and practices among Chinese pregnant women were not optimal which implies the importance of promoting their oral health during pregnancy through the improvement of knowledge and attitudes. This would facilitate formulation and implementation of appropriate oral health promotion policies.
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http://dx.doi.org/10.3390/healthcare6030077DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6163358PMC
July 2018

Candida Carriage Rate and Growth Characteristics of Saliva in Diabetes Mellitus Patients: A Case-Control Study.

J Dent Res Dent Clin Dent Prospects 2015 30;9(4):274-9. Epub 2015 Dec 30.

Department of Oral medicine and Radiology, Sree Anjaneya Institute of Dental Sciences, KUHS University, Calicut, India.

Background and aims. The aim of this study was to establish a relationship between salivary glucose levels and Candida carriage rate in type 2 diabetes mellitus patients and assess the growth characteristics and acid production of Candida in glucose-supplemented saliva. Materials and methods . A total of 90 subjects, 30 with controlled type 2 diabetes, 30 with uncontrolled type 2 diabetes and 30 without diabetes (control subjects), aged 30‒60 years, participated in the study. Unstimulated saliva was collected and investigated for glucose levels (GOD-POD method), colony-forming units (CFU) of Candida and salivary pH, using Indikrom paper strips). Analysis of statistical significance of salivary glucose and PH levels was carried out using post hoc Tukey HSD test. Correlation of Candida carriage rate with salivary glucose and salivary PH in the study groups and control group was made using Pearson's correlation. Results. Candida CFUs were significantly higher in diabetic subjects, with a significant and positive correlation with salivary glucose levels. There was a negative correlation between salivary PH levels and Candida carriage rate. Conclusion. Increased salivary glucose was associated with increased prevalence of oral Candida in diabetic subjects. The growth of Candida in saliva was accompanied by a rapid decline in PH, which in turn favored their growth.
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http://dx.doi.org/10.15171/joddd.2015.048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4753038PMC
February 2016

COCKAYNE SYNDROME: ROLE OF GENETIC COUNSELLING.

J Ayub Med Coll Abbottabad 2015 Jul-Sep;27(3):711-3

Cockayne's Syndrome (CS) is a rare autosomal recessive disorder characterized by deficiency in the transcription-couple DNA repair pathway caused by mutations in the genes ERCC6 in 65% of individuals and ERCC8 in 35% of individuals. Here we report a rare case of Cockayne's syndrome in a girl who presented with hallmark features specific to the syndrome. Dissemination of our knowledge about clinical manifestations encountered in Cockayne syndrome is instrumental not only for early evaluation and treatment to prolong life expectancy, but also to initiate early genetic counselling with parents concerning future pregnancies.
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February 2016

Can saliva offer an advantage in monitoring of diabetes mellitus? - A case control study.

J Clin Exp Dent 2014 Oct 1;6(4):e335-8. Epub 2014 Oct 1.

MDS. Department of Oral medicine and Radiology. AB Shetty Memorial Institute of Dental Sciences. Nitte University, Mangalore.

Objectives: Diabetes Mellitus is emerging as a major health problem over these years. Present method of blood glucose monitoring by venepuncture is invasive leading to reduced patient compliance and thereby ineffective judicious monitoring. The need of the hour is to direct research in the direction of establishing painless and more acceptable blood glucose analysis method.The objective of the study is to conduct a comparative analysis of the concentrations of salivary glucose and blood glucose in type 2 diabetes mellitus patients.

Study Design: This study assessed glucose levels using the glucose oxidase method in blood and unstimulated saliva in 90 subjects who were divided into 3 equal groups of controlled type 2 diabetes, uncontrolled type 2 diabetes and those without diabetes. Statistical analysis was carried out using one way ANOVA, Post hoc Tukeys tests and Pearson's correlation coefficient test.

Results: Salivary glucose levels were significantly higher in patients with diabetes than controls. There was a significant positive correlation between salivary and plasma glucose levels in patients with diabetes.

Conclusions: Glucose concentration in saliva is higher in diabetics but hyperglycemia does not influence salivary glucose levels. Further clarification is required to claim the diagnostic potentials of saliva in diabetes. Key words:Salivary glucose, type 2 diabetes mellitus, blood glucose.
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http://dx.doi.org/10.4317/jced.51386DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4282897PMC
October 2014

A rare case of unicystic ameloblastoma with luminal, intraluminal, and intramural proliferation.

Gen Dent 2014 Sep-Oct;62(5):31-3

Unicystic ameloblastoma (UCA) is a cystic lesion that shows clinical, radiographic, or gross features of an odontogenic cyst, but reveals a typical ameloblastomatous epithelium lining in the cyst cavity, with or without luminal and/or mural tumor growth. This article reports the case of a 22-year-old man with dull intermittent pain and swelling in the mandible. Histopathological examination revealed a UCA of a luminal, intraluminal, and intramural histological subgroup, which has a high risk for recurrence.
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July 2016

Xeroderma pigmentosum: man deprived of his right to light.

ScientificWorldJournal 2013 29;2013:534752. Epub 2013 Dec 29.

Department of Oral medicine and Radiology, AB Shetty Memorial Institute of Dental Sciences, Mangalore, Karnataka 575018, India.

Xeroderma pigmentosum (XP) is a hereditary autosomal recessive disorder characterized by photo hypersensitivity of sun exposed tissues and subsequent several-fold increased risk for malignant changes resulting from impaired ability to repair UV-induced DNA damage. Estimated incidences vary from 1 in 20,000 in Japan to 1 in 250,000 in the USA, and approximately 2.3 per million live births in Western Europe. Diagnosis is made clinically by the presence of unusual sunburns or lentiginosis or onset of cancers at an early age. It is confirmed by cellular tests for defective DNA repair. Although there is no cure for XP as of now, skin problems can be ameliorated with the use of sunscreens, sun avoidance methods, and recurrent tumor excisions. Oral isotretinoin and topical application of 5-fluorouracil to treat actinic keratoses are other therapeutic options. T4N5 and photolyase liposomal lotions are innovations in the therapy of XP. Genetic counselling implicating the effect of consanguineous marriages should be considered in the management of XP patients.
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http://dx.doi.org/10.1155/2013/534752DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3891433PMC
June 2014

Estimation of serum malondialdehyde in potentially malignant disorders and post-antioxidant treated patients: A biochemical study.

Contemp Clin Dent 2012 Oct;3(4):448-51

Department of Oral Medicine and Radiology, A B Shetty Memorial Institute of Dental Sciences, Nitte University, Deralakatte, Mangalore, India.

Background: Tobacco causes the generation of free radicals and reactive oxygen species (ROS) which are responsible for the high rate of lipid peroxidation. Malondialdehyde (MDA) is the most widely used agent to estimate the extent of lipid peroxidation. Timely diagnosis of the condition followed by supplementation with antioxidants like beta-carotene, pro-vitamin A, vitamin A, vitamin C, vitamin E, lipoic acid, zinc, selenium, and spirulina can prevent potentially malignant disorders.

Materials And Methods: In this study, serum MDA was measured according to the method of Buege, in 15 normal samples and 15 patients who were histopathologically diagnosed with potentially malignant disordered and they were prescribed with antioxidants for a period of 4 week-time following which potentially malignant patients serum MDA was analyzed again to determine the extent of peroxidation reactions.

Results: The mean serum MDA level in Group C1 was 0.7900 ± 0.2336 μM/L were as the mean serum MDA level of Group S1 was 2.478 ± 0.50756 μM/L and the values between them were highly significant. The values between C1 and S2 were found to be statistically significant. The mean serum MDA of S2 was 2.160 ± 0.41252 μM/L and the values were significant when compared to S1.

Conclusion: Serum MDA estimation in oral pre-cancer would serve in determining the extent of lipid peroxidation. Diagnosis of patients and administration of antioxidants has proven to be effective in declining the ROS and thus reducing the extent of damage on the cells. MDA may serve as a diagnostic tool in the estimation of oral pre-cancer and in evaluation of post-treated cases.
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http://dx.doi.org/10.4103/0976-237X.107438DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636848PMC
October 2012

Three-dimensional imaging of progressive facial hemiatrophy (Parry-Romberg syndrome) with unusual conjunctival findings.

Imaging Sci Dent 2011 Dec 19;41(4):183-7. Epub 2011 Dec 19.

Department of Oral Medicine and Radiology, AB Shetty Memorial Institute of Dental Sciences, Nitte University, Mangalore, India.

Progressive hemifacial atrophy, also known as Parry-Romberg syndrome, is an uncommon degenerative condition which is poorly defined. It is characterized by a slow and progressive atrophy affecting one side of the face. The onset usually occurs during the first two decades of life. Characteristically, the atrophy progresses slowly for several years, and then it becomes stable. Ophthalmic involvement is common, with progressive enophthalmos which is a frequent finding. Cutaneous pigmentation is common in such conditions, however its extension to the conjunctiva is rarely reported. We report a case of Parry Romberg syndrome with characteristic clinical and radiographic presentation accompanied with rare ocular findings. The clinical features, radiological findings, and differential diagnoses to be considered, and the available treatment options are discussed in this report.
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http://dx.doi.org/10.5624/isd.2011.41.4.183DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3251793PMC
December 2011

Osteogenesis Imperfecta (Type IV) with Dental Findings in Siblings.

Case Rep Dent 2011 6;2011:970904. Epub 2011 Sep 6.

Department of Oral Medicine and Radiology, AB Shetty Memorial Institute of Dental Sciences, Nitte University, Mangalore 575018, India.

Osteogenesis imperfecta (OI) is a hereditary disorder characterized by increased tendency for bone fractures due to high fragility. The clinical and radiological features of OI manifest in different age groups, although the disease is congenital in nature. Besides bone fragility, features like laxity of the ligaments, blue sclera, growth retardation, and scoliosis are also observed. In severe cases, respiratory distress and death have been reported. The most important oral finding in OI is the presence of yellowish-brown-coloured brittle teeth characteristic of dentinogenesis imperfecta. Genetic factors play a very important role in the pathogenesis of OI either as a dominant or recessive factor. When a child has OI, there is a 25% chance of the sibling to have the same disorder. We report two cases of OI in siblings born to parents with a history of consanguineous marriage. The clinical and radiological features of the two cases are described in detail.
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http://dx.doi.org/10.1155/2011/970904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3335498PMC
August 2012