Amylase Alpha 1 Gene (AMY1) Copy Number Variation and Dental Caries Experience: A Pilot Study among Adults in Lithuania

The role of AMY1 gene copy number variation in dental caries susceptibility: insights from a Turkish population

OBJECTIVE

Dental caries is a multifactorial disease influenced by environmental, behavioral, and genetic factors. Recent studies suggest that variations in the AMY1 gene, which encodes salivary amylase, may contribute to caries susceptibility. This study investigates the relationship between AMY1 gene copy number variation (CNV) and dental caries in a Turkish population.

METHOD

A total of 154 participants (63% female; mean age 19.6 ± 1.4 years) were included. Epithelial cells in inner cheek tissues were collected from volunteers using swabs, and the collected samples were preserved and stored in a DNA stabilization solution. The demographic characteristics of the volunteers were recorded, and DMFT and DMFS index scores were documented on the provided forms. The AMY1 gene CNVs were determined using a Real-time polymerase reaction device. The TaqMan chemistry, which comprises quantitative real-time PCR reactions utilizing a dual TaqMan kit, was utilized in this analysis process. Statistical analyses included the Kruskal-Wallis and Mann-Whitney U tests for group comparisons, Spearman's correlation analysis, and binomial logistic regression to evaluate associations between AMY1 CNVs and dental caries indices.

RESULTS

No statistically significant differences were observed between AMY1 CNVs and DMFT or DMFS indices (p > 0.05). However, significant associations were found between daily tooth brushing frequency and caries indices (Cramer's V = 0.219, p < 0.05), as well as between preferred beverage consumption and caries indices (Cramer's V = 0.219, p < 0.05). Other factors, including gender, dental floss and mouthwash use, and tongue brushing, did not show statistically significant associations (p > 0.05).

CONCLUSION

Although AMY1 CNVs were not significantly associated with caries indices, the findings highlight the complex interplay of genetic, behavioral, and dietary factors in caries development. This study emphasizes the critical role of oral hygiene and dietary habits in caries prevention and underscores the need for further research on genetic contributions to oral health.

CLINICAL TRIAL NUMBER

Not applicable.

The Impact of Human Salivary Amylase Gene Copy Number and Starch on Oral Biofilms

The copy number (CN) variant AMY1 encodes the salivary amylase enzyme which promotes starch digestion. Although this gene has been associated with dental caries and periodontal disease susceptibility, the impact of the interaction between AMY1 CN and starch on oral biofilms is unclear. We explored how oral microbiota communities shaped by AMY1 CN respond to starch by employing an in vitro model of biofilm formation. We cultured biofilms using saliva samples from 31 donors with a range of AMY1 CNs (between 2 and 20 copies) and self-reported gum disease states; we used media with and without starch. Many of the most prevalent genera in saliva were also prevalent in the derived biofilms. The presence of starch in the media was associated with lower biofilm alpha diversity. We found a significant interaction between AMY1 CN and the media carbohydrate content that influenced the proportions of Atopobium and Veillonella. Members of these genera have been associated with dental caries and periodontitis. These findings suggest that the effects of carbohydrates on oral microbiome composition depend on AMY1 CN and that human oral bacteria evolved in response to expansion of this host gene locus.

AMY1 gene copy number associated with xerostomia and Sjögren's syndrome: a cross-sectional study

BACKGROUND

Dry mouth-related conditions adversely affect patients' well-being, as well as their oral and general health. There are indications that the quantitative and qualitative protein composition of saliva is disrupted in patients with xerostomia and Sjögren's syndrome. Salivary α-amylase levels positively correlate with the copy number (CN) of its coding gene, AMY1 (amylase alpha 1). This study aimed to investigate the association between intensity of xerostomia, Sjögren's syndrome, and AMY1 CN. Establishing such an association could position AMY1 CN as a potential genetic biomarker for dry mouth-related conditions, aiding in their early detection.

METHODS

This cross-sectional study utilized secondary data from the main dry mouth study conducted in five public hospitals in Vilnius, the capital city of Lithuania. Based on sample size calculations for the main study, 127 patients who met the inclusion criterion of dry mouth complaints (sometimes, often, and always) were recruited. The outcomes were xerostomia intensity, assessed using a visual analogue scale (VAS), and confirmed cases of Sjögren's syndrome, assessed using the 2016 ACR/EULAR classification criteria and classified as either primary or secondary. Sociodemographic information included age and sex; self-perceived stress levels were assessed using the Perceived Stress Scale (PSS-10). During clinical examinations, unstimulated whole sialometry was performed for 15 min, and oral mucosa swabs were collected. The swabs were used to quantify AMY1 CN via droplet digital PCR (ddPCR). Data were analyzed using both univariable and multivariable regression models.

RESULTS

In total, 112 patients with available AMY1 CN data and recorded xerostomia intensity VAS scores were included in this study. Of these, 26 (23%) were diagnosed with Sjögren's syndrome; 9 (8%) had primary and 17 (15%) had secondary Sjögren's syndrome. According to multivariable linear regression analyses, higher AMY1 CN was associated with 0.15 lower xerostomia intensity VAS score (β =-0.15, 95% CI -0.30, -0.01). Higher AMY1 CN reduced the odds for primary Sjögren's syndrome (OR 0.52, 95% CI 0.03-0.89).

CONCLUSIONS

The present study indicated an inverse association between xerostomia, primary Sjögren's syndrome, and AMY1 CN. Studies validating these findings and exploring the underlying mechanisms are warranted.

Salivary IL-6 as a Biomarker for Early Childhood and Rampant Caries: Insights from a Cross-Sectional Study

Objectives: This study aimed to explore the levels of salivary interleukin-6 (IL-6) in children diagnosed with Early Childhood Caries (ECC) and Rampant Caries (RC). Additionally, it sought to determine whether salivary IL-6 levels vary with the increased activity or number of carious lesions in children with ECC and RC. Methods: A cross-sectional study was conducted at RAK College of Dental Sciences (RAKCODS), Ras Al Khaimah, UAE. Ethical approval was obtained, and 100 children aged 4 to 12 years were selected. Participants were divided into ECC and RC groups, each containing study and control subgroups of 25 children each. The study groups were children who had active carious lesions and the control groups were those children who had no active carious lesions. All of these children were screened and included as a part of the community engagement of the clinics. Saliva samples were collected and analyzed for IL-6 levels using an ELISA kit. Dental examinations and data collection adhered to standardized procedures, including specific clinical criteria for diagnosing ECC and RC and calibrated examiners to ensure consistent clinical assessments. Statistical analyses were conducted to compare salivary IL-6 levels between the study and control groups of each RC and ECC group and a test was also performed to assess the relationship between salivary IL-6 levels and the severity of dental caries. Results: This study found significantly higher mean salivary IL-6 levels in children with ECC (19.023 pg/mL) and RC (21.45 pg/mL) compared to their respective control groups (ECC: 6.42 pg/mL, RC: 11.43 pg/mL), with p-values < 0.0001. Strong positive correlations were observed between IL-6 levels and increased caries activity or severity, with Pearson's correlation coefficients of 0.961 for ECC and 0.954 for RC. Conclusions: This study concludes that significantly elevated salivary IL-6 levels are observed in children with ECC and RC. Furthermore, salivary IL-6 levels were found to rise in correlation with the increase in number of carious lesions. These findings support the potential of salivary IL-6 as a biomarker for assessing caries severity and highlight the need for future research to explore diverse populations and additional clinical parameters.

Salivary alpha-amylase activity and its association with early childhood caries and rampant caries experience: a cross-sectional study

Aims

This study aims to evaluate salivary alpha-amylase levels in children diagnosed with Early Childhood Caries (ECC) and Rampant Caries (RC) and compare them to levels in children without ECC or RC. It also examines the relationship between salivary alpha-amylase levels and increased caries activity in the children with ECC or RC.

Materials and methods

A cross-sectional study was conducted at RAK College of Dental Sciences (RAKCODS) with 100 children aged 3-12 years. Participants were divided into ECC and RC groups, each consisting of study and control groups. Salivary alpha-amylase levels were measured using Enzyme-Linked Immunosorbent Assay (ELISA) kits. Statistical analyses, including the Wilcoxon Signed Rank test and Pearson's correlation coefficient, were performed using SPSS version 29 to compare salivary alpha-amylase levels between groups and examine correlation with severity of dental caries.

Results

The study found that children with ECC and RC had significantly higher mean salivary alpha-amylase levels (16.046 U/mL and 20.62 U/mL, respectively) compared to control groups (5.09 U/mL and 12.70 U/mL). The differences were statistically significant (p < 0.0001). Pearson's correlation coefficients indicated a strong positive correlation between salivary alpha-amylase levels and severity of dental caries in both ECC (r = 0.9891, p < 0.0001) and RC (r = 0.9142, p < 0.0001) groups.

Conclusion

The study concludes that elevated salivary alpha-amylase levels, which are statistically significant, are observed in children with ECC and RC. Additionally, it was found that salivary alpha-amylase levels increased with the number of carious lesions. These findings suggest that salivary alpha-amylase could serve as a valuable biomarker for assessing caries risk and guiding preventive strategies.

Genetics Affecting the Prognosis of Dental Treatments

Genetics plays a significant role in determining an individual's susceptibility to dental diseases, the response to dental treatments, and the overall prognosis of dental interventions. Here, the authors explore the various genetic factors affecting the prognosis of dental treatments focusing on dental caries, orthodontic treatment, oral cancer, prosthodontic treatment, periodontal disease, developmental disorders, pharmacogenetics, and genetic predisposition to faster wound healing. Understanding the genetic underpinnings of dental health can help personalize treatment plans, predict outcomes, and improve the overall quality of dental care.

Dental caries prevalence and severity positively associate with AMY1 gene copy number

OBJECTIVE

To establish the possible relation between total caries (TC) and caries severity (CS) with the AMY1 gene copy number (AMY1GCN).

MATERIALS AND METHODS

This was an observational, cross-sectional, population-based, and association study with 303 participants. Each participant underwent a complete anamnesis and stomatological check-up, and peripheral blood was obtained to extract gDNA. TC and CS were determined as the number of caries at the dental exploration and the number of dental surfaces affected by caries, respectively, and AMY1GCN was determined by qPCR.

RESULTS

We found an elevated caries prevalence (92.7%); TC and CS were 8 ± 10 and 10 ± 13 (median ± IR). There were higher TC and CS in those participants with AMY1GCN above the mean value (0.02 and 0.01 p values, respectively). A positive correlation between TC and CS with AMY1GCN (0.11 and 0.125 r values, 0.03 and 0.01 p values, respectively) was found, in addition to an association between TC and CS with AMY1GCN (1.5 and 1.6 OR values, 0.48 and 0.26 p values, respectively).

CONCLUSION

TC and CS were positively related to the AMY1GCN.

CLINICAL RELEVANCE

Dental caries has a high prevalence and a multifactorial etiology and has been related to a genetic component. Indeed, the salivary enzyme alpha-amylase could play a significant role in caries susceptibility, considering that its codifying gene (AMY1) can show variation in its gene copy number. This can be considered an important factor for the development of caries at a genetic level.

A protospacer adjacent motif-free, multiplexed, and quantitative nucleic acid detection platform with barcode-based Cas12a activity

Clustered regularly interspaced short palindromic repeat (CRISPR)-based biosensors have been developed to facilitate the rapid and sensitive detection of nucleic acids. However, most approaches using CRISPR-based detection have disadvantages associated with the limitations of CRISPR RNA (crRNA), protospacer adjacent motif (PAM) or protospacer flanking sequence restriction, single channel detection, and difficulty in quantitative detection resulting in only some target sites being detected qualitatively. Here, we aimed to develop a barcode-based Cas12a-mediated DNA detection (BCDetection) strategy, which overcomes the aforementioned drawbacks and enables (1) detection with a universal PAM and crRNA without PAM or crRNA restriction, (2) simultaneous detection of multiple targets in a single reaction, and (3) quantitative detection, which can significantly distinguish copy number differences up to as low as a two-fold limit. We could efficiently and simultaneously detect three β-thalassemia mutations in a single reaction using BCDetection. Notably, samples from normal individuals, spinal muscular atrophy (SMA) carriers, and SMA patients were significantly and accurately distinguished using the quantitative detection ability of BCDetection, indicating its potential application in β-thalassemia and SMA carrier screening. Therefore, our findings demonstrate that BCDetection provides a new platform for accurate and efficient quantitative detection using CRISPR/Cas12a, highlighting its bioanalytical applications.

Relationship between Salivary Alpha-Amylase Enzyme Activity, Anthropometric Indices, Dietary Habits, and Early Childhood Dental Caries

Objectives

Although early childhood dental caries (ECC) have the same general etiology as other types of caries, predisposing factors are not well elucidated. This study aimed to investigate the effect of salivary alpha-amylase (sAA) activity, body mass index (BMI), dietary habits, and oral hygiene on ECC.

Methods

This cross-sectional study was performed on 38 ECC-affected and 41 caries-free children, aged 36 to 72 months. Upon the parents' consent, 3 mL of non-stimulated saliva was collected from the participants to measure the level of sAA activity through spectrophotometry. Additionally, parents/caretakers completed a structured questionnaire about demographic factors, oral hygiene, and consumption of sugar-containing foods. BMI, BMI z-scores, and percentile data were calculated by using an online calculator. The independent variables were dichotomized and tested through chi-square test, followed by a stepwise logistic regression, by using SPSS software (α = 0.05).

Results

The sAA activity was significantly higher in caries-free children (P ≤ 0.001). However, the mean BMI was not significantly different between the two groups (P=0.49). Brushing and other measured dietary habits were significantly associated with the development of ECC (P ≤ 0.001). According to the results of the logistic regression, sAA activity was shown to be a predictor for ECC development (Odds ratio (95% confidence interval): 0.9 (0.95-0.98)).

Conclusion

Children with inherently lower levels of sAA activity were more susceptible to dental caries. Improper nutritional habits and poor oral health care could exacerbate the risk of ECC.

Fluoride in the drinking water and dental caries experience by tooth surface susceptibility among adults

Background

Dental caries is the most prevalent non-communicable health condition globally. The surface-based susceptibility hierarchy indicates that surfaces in the same group have similar susceptibility to caries, where the most susceptible group consists of occlusal surfaces of first molars and buccal surfaces of lower first molars, and the least susceptible surfaces are smooth and proximal surfaces of first premolars, canines and incisors. Therefore, fluoride in the drinking water could impact one group more than the other group. The present study examined the association between fluoride levels in the drinking water and dental caries experience in adults in the context of varying tooth surface susceptibility.

Methods

Data from the cross-sectional National Lithuanian Oral Health Survey conducted in 2017–2019 included a stratified random sample of 1398 35–74-year-olds (52% response rate). Dental caries experience in dentine was measured at a surface level. The surfaces were grouped according to their caries susceptibility (group 1 being the most and group 4 the least susceptible), and dental caries experience was calculated separately for each susceptibility group, creating four outcomes. Information about explanatory variable, fluoride levels in the drinking water, was provided by the water suppliers. The questionnaire inquired about potential determinants: sociodemographic characteristics and oral health-related behaviors. Chi-square, Mann–Whitney U and Kruskal Wallis tests were used for descriptive statistics, and linear regression analyses to examine the association between fluoride levels and four outcomes.

Results

The proportions of median decayed, missing, filled surfaces decreased following the surface-based susceptibility hierarchy (group 1–33%, group 2–28%, group 3–24%, group 4–15%). When adjusted for potential determinants, higher-level fluoride (≥ 0.7 ppm vs < 0.7 ppm) in the drinking water associated with lower dental caries experience in all surface-based susceptibility hierarchy groups; Group 1: β = − 0.23 (95 %CI − 0.44; − 0.001), Group 2: β = − 0.44 (95 %CI − 0.82; − 0.07), Group 3: β = − 1.14 (95 %CI − 1.88; − 0.41) and Group 4: β = − 6.28 (95 %CI − 9.29; − 3.30).

Conclusions

The higher-level fluoride in the drinking water associated with lower dental caries experience in adults and this was observed in all surface-based susceptibility groups. However, there is a need to validate the surface-based susceptibility hierarchy in longitudinal adult studies.