Oral Diseases. 2018;24:372–376.
Received: 25 November 2016
Revised: 31 August 2017
Accepted: 15 September 2017
The impact of MUC5B gene on dental caries
T Cavallari | H Salomão | ST Moysés | SJ Moysés | RI Werneck
© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. All rights reserved
Graduate Program in Dentistry, School of Life
Sciences, Pontifícia Universidade Católica do
Paraná, Curitiba, Brazil
Renata Iani Werneck, Department of
Dentistry, Pontifícia Universidade Católica do
Paraná, Curitiba, Brazil.
Pontifícia Universidade Católica do Paraná;
Conselho Nacional de Desenvolvimento
Científico e Tecnológico (CNPq), Grant/Award
Objective: To identify the impact of MUC5B polymorphisms on dental caries.
Methods: A case–control study was performed with patients recruited at Pontifícia
Universidade Católica do Paraná. These individuals were aged 12 years old or more.
Dental caries was diagnosed using the International Caries Detection and Assessment
System, and the effects of socioeconomic, dietary, and hygiene factors on dental caries
were investigated. Furthermore, buccal cells were collected, and their DNA was ex-
tracted and amplified using PCR. Uni- , bi- , and multivariate analyses were performed.
Results: Two hundred patients were recruited, 100 were assigned to the case group
and 100 to the control group. In the bivariate analysis, the following variables showed
significant results: ethnicity (p = .008), biofilm (p < .001), and gingivitis (p < .001). The
MUC5B gene affected dental caries with the markers rs2735733 (p < .001), rs2249073
(p < .001), and rs2857476 (p < .001). In the multivariate analysis, the biofilm variable
remained significant (p = .026), as did the following markers from the MUC5B gene:
rs2735733 (p = .019), rs2249073 (p < .025), and rs2857476 (p < .005).
Conclusion: Genetic variations in the MUC5B gene can influence dental caries.
dental diseases, epidemiology, genetics
1 | INTRODUCTION
Dental caries is a chronic, complex, and multifactorial disease
(Fejerskov, 2004) that is highly prevalent in both industrialized and de-
veloping countries (Petersen, 2003). According to the latest epidemio-
logical survey, the DMFT index (number of decayed, missing, and filled
teeth) has declined, nonetheless, dental caries continues to be one of
the major diseases in oral health (Petersen, 2005). It is widely accepted
that the occurrence of the disease depends on environmental (distal)
and host (proximal) factors. One of the proximal risk factors for devel-
oping dental caries is saliva composition (Fejerskov & Manji, 1990).
Saliva contains salivary mucins (MUC7, MUC1, and MUC5B) that
cover and protect the mucosa and tooth surfaces. They also maintain
the viscoelastic, hydrophobic, and lubricative properties of saliva.
There are two genetically distinct types of mucins: high molecular
weight (MG1) and low molecular weight (MG2). The MG1 mucin is
encoded by the MUC5B gene. MG1 mucin consists of 15% protein
and 78% carbohydrate, and it appears to exist as oligomeric and
monomeric units. MG1 mucin is synthesized in the mucous cells of the
submandibular, sublingual, and other minor glands (Pol et al. 2007).
The MUC5B gene is located in chromosome 11 (11p15.5), and the
protein functions to form a gel that provides viscosity to the saliva
(Frenkel & Ribbeck, 2014; Thornton et al., 1999).
Some researchers have already demonstrated that mucins are as-
sociated with dental caries (Frenkel & Ribbeck, 2014; Porowska et al.,
2014). According to Frankel, the MUC5B gene reduces the attachment
of Streptococcus mutans and inhibits biofilm formation. Therefore,
reduced levels of MUC5B in the pellicle leave teeth vulnerable to
Streptococcus mutans attachment and subsequent cavity formation
(Frenkel & Ribbeck, 2014).
Several risk factors are known to confer a predisposition to dental
caries. However, there are also some individual variations that might
explain why some individuals develop the disease when exposed to
some risk factors and others do not. Moreover, advances in our knowl-
edge of molecular biology and the human genome have allowed re-
searchers to investigate whether dental caries and other oral diseases