According to the study, breastfeeding until the age of one is not associated with an increased risk of tooth decay and may even be protective compared to formula. In contrast, infants who were breastfed after the age of one year showed an increase in S-ECC levels (12). Prevalence of ECC has been reported up to 71% in the world. In Iran, the prevalence of S-ECC in different regions has been reported 10% to 45% (13-15). Therefore, this study was conducted due to the high prevalence of S-ECC in Iran and many countries, and a likely relationship between prevalence and severity of S-ECC with the amount of breast milk lactose and lack of related studies.
This study was approved by the ethics committee of Kerman University of Medical Sciences with the code IR.KMU.REC.1398.549. The cross-sectional descriptive-analytical study was performed on 30 children of 12 to 24 months with or without S-ECC. The mothers who did not consent to participate in the study were excluded. The study population was selected from mothers who brought their children to public health centers in Kerman for vaccination as well as to the pediatric dentistry clinics. The mothers were interviewed by third author and they were selected from low socio-economic families because ECC is more prevalent in these families. The children were examined for maxillary anterior teeth in a knee-to-knee position. Clinical examination of children's teeth was performed by disposable oral mirror after drying the surface of maxillary incisors. The presence of any signs of caries on the labial surfaces of the four maxillary incisors was assessed for S-ECC diagnosis, and the presence or absence of caries was noted in the relevant checklist. Inclusion criteria for the mothers are the following:
1- Age at delivery between 18 to 45 years
2. Pregnancy period of 37 weeks and more.
1- Diabetes 2- Tobacco and/or alcohol consumption
3. Feeding by formula
Mothers were asked to answer the checklist questions while reading and signing the informed consent form to participate in the study. Finally, they extracted 10 to 20 ml of milk by hand or with a special pump to a collection tube.
To ensure blindness, all collection tubes were coded as recorded in the consent form and checklist. The samples were immediately placed at -4 ° C and kept at this temperature until the experiment was performed. On the day of the experiment, the samples were transferred to the laboratory.
For the measurement of lactose, phenol-sulfuric acid method, which is one of the most common methods for measuring carbohydrates in solution, was adopted. Initially, to draw a standard curve for lactose, specific concentrations of lactose were prepared (concentrations of 400-200-100-50 μg / ml). The milk samples were then centrifuged in Falcon tubes to separate lactose at 10,000 rpm for 7-8 minutes. Samples were taken from the supernatant and added to the numbered test tubes. To each tube was added 10 μl of milk sample with 1990 μl of water. Then, the steps were taken to draw a standard curve, which included the addition of 50 μl of 80% phenol and 5 ml of sulfuric acid immediately, and mixing on the device to completely mix the acid with the solution. Then, the tubes were kept fixed for 10 minutes. After that, the tubes were shaken again for 2 seconds and placed in a 30-degree oven for 20 minutes. The spectrophotometer [Shimadzu Co., Japan] was again zeroed with the blank solution and then the wavelength of the samples was read at 490 nm. The wavelengths obtained from each sample were recorded. Finally, the absorptions obtained from the milk samples were placed in the line equation of the standard lactose diagram, and the equivalent concentration was obtained. The number obtained was multiplied by 200 (because the milk sample was diluted 200 times) and lactose concentration was calculated in mg / L. To report values in percentage, (g of lactose in 100 ml of milk) the numbers were divided by 10,000 and the concentrations obtained from the sample were recorded.
The obtained data were statistically analyzed by a statistical expert using SPSS 21 software. Independent t-test was used to evaluate the relationship between the amount of the milk lactose and suffering from ECC.