title: spaP gene of Streptococcus mutans in dental plaque and its relationship with early childhood caries.
abstract: OBJECTIVE
  Streptococcus mutans and Streptococcus sobrinus are the main pathogens associated with the development  of dental caries in humans. Recently, the real-time polymerase chain reaction (qPCR-TR) has been used for fast and exact  quantification of these bacteria species. This molecular biology method has made the detection of these bacteria in saliva  and dental plaque possible; additionally, it aids the development of illness risk prediction. The purpose of this prospective,  analytic, transversal, observational and unicenter study was to quantify the spaP gene of the Streptococcus mutans and its  correlation with caries in a group of children using isolated DNA from plaque samples processed through qPCR-TR, using  specific oligonucleotides for this gene detection.
  
  
  METHODS
  The cariogenic potential of Streptococcus  mutans in the dental plaque was analysed in a group of patients aged 12 to 46 months. A descriptive statistical analysis was  performed. The Spearman's correlation coefficient was used to establish the correlation between caries (dmft) index  (decayed/missing/filled primary teeth), spaP gene and age group. The Wilcoxon test was used to compare MSB cultivation  technique and qPCR-TR.
  
  
  RESULTS
  In the molecular trials, a close association between caries prevalence in childhood and  the presence and high proportion of the spaP gene of S. mutans was found. The average caries prevalence was 3.71, and it  increased as age range increased. The highest caries prevalence was observed in female patients and in the oldest age  range studied (40 46 months) which contrasts with the 12-18 months age that had a caries (dmft) index of zero. The  amplification using as initiator the gene spaP of the nucleic acids extracted from the S. mutans resulted positive in  91.3% of the cases. Every child with caries was positive for the spaP and only 8.75% were negative, this group  included children without caries.
  
  
  CONCLUSIONS
  In conclusion, there was a correlation with infant caries prevalence and S.  mutans.
authors.affiliation: Department of Dental pediatrics, Universidad Autónoma de Nuevo León, Mexico. gennyduran@hotmail.com
authors.forename: G L
authors.initials: GL
authors.lastname: Durán-Contreras
authors.forename: H H
authors.initials: HH
authors.lastname: Torre-Martínez
authors.forename: E I
authors.initials: EI
authors.lastname: de la Rosa
authors.forename: R M
authors.initials: RM
authors.lastname: Hernández
authors.forename: M
authors.initials: M
authors.lastname: de la Garza Ramos
mesh_terms: D000367:Age Factors; D002675:Child, Preschool; D004245:DMF Index; D004269:DNA, Bacterial / Q000032:analysis; D003731:Dental Caries / Q000453:epidemiology* / Q000382:microbiology; D003773:Dental Plaque / Q000382:microbiology*; D005260:Female; D005798:Genes, Bacterial; D006801:Humans; D007223:Infant; D008297:Male; D015995:Prevalence; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D013295:Streptococcus mutans / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial