Edited by: Ariane Berdal, Cordeliers Research Centre (INSERM), France
Reviewed by: Eric Everett, University of North Carolina at Chapel Hill, United States; Thomas G. H. Diekwisch, Texas A&M University Baylor College of Dentistry, United States
*Correspondence: Ye Tao
Huancai Lin
This article was submitted to Craniofacial Biology and Dental Research, a section of the journal Frontiers in Physiology
This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Genetic studies have shown that variations in enamel formation genes are associated with caries susceptibility. The aim of this study was to test
Enamel is the most highly mineralized tissue in the human body. The amelogenesis phase of enamel development is strictly controlled by enamel formation genes (Fincham et al.,
The effects of enamel formation genes on caries susceptibility are impacted by environmental factors, such as fluoride exposure (Shaffer et al.,
Single nucleotide polymorphisms (SNPs) (Table
The value of α was set at 0.017, and the value of β was set at 0.1. The values of
Candidate genetic markers evaluated in this study.
AMELX | Xp22.31 – p22.1 | rs946252 | C/T (0.427) |
AMBN | 4q21 | rs4694075 | C/T (0.464) |
rs7694409 | A/G (0.244) | ||
rs13115627 | A/G (0.250) | ||
ENAM | 4q13.3 | rs12640848 | A/G (0.292) |
TUFT1 | 1q21 | rs6587597 | G/A (0.399) |
rs16833391 | C/T (0.161) | ||
rs17640579 | A/G (0.321) | ||
rs12749 | G/A (0.232) | ||
rs3790506 | G/A (0.321) | ||
TFIP11 | 22q12.1 | rs2097470 | C/T (0.286) |
rs134143 | T/C (0.363) | ||
KLK4 | 19q13.41 | rs198968 | A/G (0.131) |
MMP20 | 11q22.3-q23 | rs2292730 | G/A (0.202) |
rs1784418 | C/T (0.470) | ||
rs1612069 | G/T (0.429) |
The project was approved by the Ethical Review Committee of Guanghua School of Stomatology, Sun Yat-Sen University (ERC-2015-15). The subjects were given verbal and written information regarding the study, and they provided written consent to participate. Eligible unrelated individuals were recruited using quota sampling at the Department of Oral and Maxillofacial Surgery, Hospital of Stomatology, Sun Yat-Sen University and Guangdong Provincial Stomatological Hospital from September 2015 to January 2017. These hospitals are the two largest stomatological hospitals in Guangdong Province. To be eligible for inclusion in the study, subjects were required to be the following: (1) of Chinese Han ethnicity, (2) aged between 13 and 18 years old, (3) individuals whose premolars were extracted for orthodontic reasons, and (4) systemically healthy. Furthermore, teeth were required to be/have the following: (1) complete development of the apical part of the root, (2) a sound premolar without visible caries or restorations, and (3) healthy teeth without enamel hypoplasia or dental fluorosis. One to three premolars from each subject were collected and stored in a container containing 0.1% thymol solution at 4°C until use. Saliva samples (2 ml each) were obtained from each participant and stored using Oragene DNA Self-Collection kits (Lang Fu, China). In total, 213 subjects were enrolled in this study. Those subjects contributed 447 teeth. Figure
Summary of study design.
Before each tooth was sectioned, it was thoroughly cleaned of debris and gingival tissues. The teeth were cut in half mesially–distally and coronally–apically, leaving the buccal surface halves. The lingual halves and the root were removed using a cutter bar (Accutom-50, Struers, Denmark). The flattest central portion of the buccal surface was used to prepare a 3 × 3 × 3 mm cuboidal tooth block. One enamel specimen was prepared from each tooth. The prepared enamel block was polished on a rotating polishing machine using progressively finer grades of SiC grinding paper under water cooling (Tegramin preparation system, Struers, Denmark). It was previous reported that when the outer 100 μm of the enamel is polished, there is no significant difference in superficial microhardness between unerupted enamel and enamel 10 years after eruption (Palti et al.,
Preparation of enamel specimens.
The microhardness of each specimen was determined by a microhardness tester (DuraScan-20; Struers, Denmark) at a load of 100 g for 15 s. The average surface microhardness was determined from three indentations placed in the center of the surface of each specimen. The spaced indentations were 100 μm away from each other.
Elemental microanalyses were performed using an Electron Probe Micro Analyzer (JXA-8800R, JEOL, Tokyo, Japan) equipped with Wavelength Dispersive X-ray Spectroscopy (WDS). The standards used for calibration were Apatite [Ca5 (PO4)5(F, Cl, OH)], for calcium and phosphate, and diopside (MgO) for magnesium. The counting time at each point was 10 s with a 1 mm diameter of the electron beam at 15.0 kV and 20 nA. In this test, the relative amounts of the three elements and the calcium-phosphorus ratio were calculated based on the mean of the three points which were measured in the center of the surface of each specimen. Each point was approximately 50 μm away from each other.
The tooth blocks were subjected to steam autoclaving (121°C for 15 min) (Amaecha et al.,
After artificial caries formation, each tooth block was placed in a resin tube 9 mm in diameter and scanned using micro-CT (μCT 50, Scanco Medical AG, Switzerland). The X-ray source was operated at a voltage of 70 kV with a current of 200 kA and an exposure time of 1,500 ms. The highest spatial resolution used during scanning was 5 μm. A 0.5-mm aluminum filter was used to block the weakest X-rays. During scanning, the tooth block was placed in the tube with the exposed enamel surface perpendicular to the sidewall of the tube. Then, a wet sponge was placed in the tube to fix the position of the tooth block and maintain block moisture. The scanning results for each specimen were reconstructed using μCT-reconstruction software (μCT50, Scanco, Bassersdorf, Switzerland). The reconstructed 3D images were viewed and processed using μCT evaluation software (μCT50, Scanco, Bassersdorf, Switzerland). From the reconstructed 3D images of each specimen, cross-sectional images of each specimen were located. From these lesion images, 10 were randomly selected. Lesion depth was measured using the image analysis software Image J (National Institutes of Health, USA) (Mei et al.,
This calibration equation was used to transform the gray level values of the images into true mineral density (MD) values. The MD value of the region of interest (ROI) in the 10 selected cross-sectional images was measured. In the carious lesions, the ROI was 20 × 20 pixels (100 × 100 μm) located precisely in the middle of the lesion just below the exposed tooth surface. In the healthy part, the ROI was 20 × 20 pixels (100 × 100 μm) in the corresponding position, which was located by determining the same distance from the upper surface. Measurements were taken in each lesion and protected area, and the mean of these measurements was used as the MD of the lesion and sound enamel. Mineral loss (%) was calculated by subtracting the lesion MD value from the sound enamel MD value and then dividing the result by the sound enamel MD value (Lo et al.,
Genomic DNA was extracted from saliva samples according to the manufacturer's instructions. Spectrophotometry was used to determine the DNA concentration and purity of each sample. The DNA concentration was evaluated at 260 nm, and the ratio of the readings obtained at 260 and 280 nm was used to estimate DNA purity. Sixteen markers in seven genes known to be involved in enamel formation were selected for analysis in this study. The rs134143 genotype was determined by direct sequencing and genotyping of other 15 SNPs was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).
All of the data were analyzed on a personal computer using SPSS 22.0. Before analysis, the mineral loss data were transformed using the arcsine square root transformation. Because neither mineral loss nor lesion depth had a normal distribution, a general linear model was used to investigate the influence of SNP status on enamel microhardness, chemicals and enamel demineralization properties. Intergroup comparisons were performed using a
Two hundred and thirteen subjects (155 females and 58 males) were included in the study. Sixteen SNPs distributed across the following seven enamel matrix genes were investigated:
Enamel microhardness by sex.
Male ( |
339.54 ± 23.19 |
0.408 |
Enamel chemical properties by sex.
Male ( |
0.19 ± 0.04 |
0.386 |
39.36 ± 0.92 |
0.391 |
18.56 ± 0.34 |
0.467 |
2.12 ± 0.08 |
0.847 |
Enamel demineralization properties by sex.
Male ( |
194.57 ± 10.75 |
0.14 |
49.15 ± 5.2 |
0.90 |
Table
Summary of the microhardness comparisons by genotype.
CC (52) | 336.35 ± 26.59 | |||
AMELX | rs946252 | CT (45) | 337.42 ± 19.00 | 0.943 |
TT (36) | 337.72 ± 16.55 | |||
CC (22) | 337.29 ± 22.04 | |||
AMBN | rs4694075 | CT (62) | 336.35 ± 24.21 | 0.861 |
TT (50) | 338.62 ± 18.14 | |||
AA (89) | 337.05 ± 20.27 | |||
rs7694409 | AG (36) | 338.31 ± 25.25 | 0.618 |
|
GG (6) | 328.89 ± 20.76 | |||
AA (89) | 337.67 ± 20.31 | |||
rs13115627 | AG (37) | 337.25 ± 25.16 | 0.917 |
|
GG (8) | 334.33 ± 20.93 | |||
AA (79) | 336.66 ± 23.68 | |||
ENAM | rs12640848 | AG (44) | 338.03 ± 19.50 | 0.887 |
GG (11) | 339.61 ± 14.34 | |||
AA (62) | 336.38 ± 21.33 | |||
KLK4 | rs198968 | AG (62) | 338.17 ± 23.05 | 0.891 |
GG (10) | 338.30 ± 14.86 | |||
CC (80) | 336.48 ± 19.98 | |||
TFIP11 | rs2097470 | CT (46) TT (8) | 340.62 ± 20.55 |
0.236 |
CC (6) | 336.67 ± 23.03 | |||
rs134143 | CT (65) | 340.73 ± 22.67 | 0.206 |
|
TT (63) | 333.93 ± 20.16 | |||
AA (8) | 339.96 ± 17.84 | |||
MMP20 | rs2292730 | AG (51) | 336.55 ± 23.49 | 0.907 |
GG (75) | 337.62 ± 20.90 | |||
CC (39) | 333.54 ± 23.76 | |||
rs1784418 | CT (62) | 339.50 ± 18.78 | 0.403 |
|
TT (33) | 337.84 ± 23.99 | |||
GG (37) | 336.24 ± 21.96 | |||
rs1612069 | GT (67) | 341.18 ± 19.34 | ||
TT (28) | 327.49 ± 22.74 | |||
AA (25) | 344.56 ± 15.78 | |||
TUFT1 | rs6587597 | AG (70) | 336.79 ± 21.57 | 0.236 |
GG (38) | 333.06 ± 24.20 | |||
CC (96) | 335.85 ± 20.62 | |||
rs16833391 | CT (34) | 341.48 ± 23.46 | 0.365 |
|
TT (3) | 330.11 ± 32.17 | |||
AA (64) | 334.55 ± 20.86 | |||
rs17640579 | AG (55) | 337.16 ± 22.96 | ||
GG (15) | 350.00 ± 15.73 | |||
AA (8) | 324.46 ± 38.61 | |||
rs12749 | AG (42) | 341.03 ± 18.46 | 0.127 |
|
GG (84) | 336.74 ± 20.80 | |||
AA (14) | 346.90 ± 21.14 | |||
rs3790506 | AG (61) | 337.72 ± 21.67 | 0.162 |
|
GG (58) | 337.33 ± 21.58 |
Summary of the enamel chemical comparisons by genotype.
CC (51) | 0.18 ± 0.05 | 39.30 ± 0.94 | 18.51 ± 0.33 | 2.12 ± 0.07 | ||||||
AMELX | rs946252 | CT (40) | 0.19 ± 0.04 | 0.361 |
39.33 ± 0.90 | 0.633 |
18.51 ± 0.36 | 0.599 |
2.13 ± 0.07 | 0.471 |
TT (37) | 0.18 ± 0.05 | 39.15 ± 0.84 | 18.58 ± 0.37 | 2.11 ± 0.07 | ||||||
CC (21) | 0.19 ± 0.05 | 39.36 ± 0.83 | 18.39 ± 0.43 | 2.14 ± 0.07 | ||||||
AMBN | rs4694075 | CT (62) | 0.18 ± 0.05 | 0.479 |
39.14 ± 0.89 | 0.330 |
18.59 ± 0.36 | 0.073 |
2.11 ± 0.07 | 0.093 |
TT (47) | 0.18 ± 0.03 | 39.38 ± 0.92 | 18.51 ± 0.28 | 2.13 ± 0.07 | ||||||
AA (77) | 0.18 ± 0.04 | 39.35 ± 0.93 | 18.51 ± 0.32 | 2.13 ± 0.07 | ||||||
rs7694409 | AG (44) | 0.18 ± 0.05 | 39.21 ± 0.85 | 0.418 |
18.58 ± 0.34 | 0.151 |
2.11 ± 0.07 | 0.513 |
||
GG (6) | 0.22 ± 0.05 | 38.90 ± 0.84 | 18.30 ± 0.69 | 2.13 ± 0.12 | ||||||
AA (78) | 0.18 ± 0.04 | 39.32 ± 0.93 | 18.50 ± 0.32 | 2.13 ± 0.07 | ||||||
rs13115627 | AG (45) | 0.18 ± 0.05 | 0.061 |
39.13 ± 0.79 | 0.415 |
18.62 ±0.34 | 2.10 ± 0.06 | |||
GG (7) | 0.22 ± 0.05 | 39.49 ± 1.19 | 18.22 ± 0.56 | 2.17 ± 0.11 | ||||||
AA (81) | 0.18 ± 0.04 | 39.26 ± 0.87 | 18.60 ± 0.33 | 2.11 ± 0.07 | ||||||
ENAM | rs12640848 | AG (38) | 0.18 ± 0.05 | 0.590 |
39.20 ± 0.90 | 0.769 |
18.39 ± 0.37 | 2.13 ± 0.07 | 0.222 |
|
GG (11) | 0.19 ± 0.05 | 39.43 ± 1.08 | 18.47 ± 0.29 | 2.14 ± 0.07 | ||||||
AA (53) | 0.18 ± 0.05 | 39.34 ± 0.92 | 18.45 ± 0.39 | 2.13 ± 0.08 | ||||||
KLK4 | rs198968 | AG (64) | 0.18 ± 0.04 | 0.260 |
39.19 ± 0.88 | 0.641 |
18.58 ± 0.31 | 0.103 |
2.11 ± 0.06 | 0.174 |
GG (13) | 0.16 ± 0.04 | 39.30 ± 0.89 | 18.57 ± 0.36 | 2.12 ± 0.07 | ||||||
CC (75) | 0.19 ± 0.04 | 39.29 ± 0.83 | 18.57 ± 0.31 | 2.12 ± 0.06 | ||||||
TFIP11 | rs2097470 | CT (49) | 0.17 ± 0.04 | 39.25 ± 0.98 | 0.792 |
18.47 ± 0.41 | 0.300 |
2.13 ± 0.08 | 0.663 |
|
TT (6) | 0.18 ± 0.07 | 39.03 ± 1.05 | 18.54 ± 0.37 | 2.11 ± 0.08 | ||||||
CC (4) | 0.20 ± 0.08 | 39.00 ± 1.36 | 18.64 ± 0.38 | 2.09 ± 0.10 | ||||||
rs134143 | CT (67) | 0.17 ± 0.04 | 0.075 |
39.27 ± 0.90 | 0.841 |
18.46 ± 0.40 | 0.077 |
2.13 ± 0.08 | 0.334 |
|
TT (59) | 0.19 ± 0.04 | 39.27 ± 0.87 | 18.60 ± 0.28 | 2.11 ± 0.06 | ||||||
AA (11) | 0.16 ± 0.04 | 39.47 ± 0.80 | 18.29 ± 0.34 | 2.16 ± 0.07 | ||||||
MMP20 | rs2292730 | AG (43) | 0.18 ± 0.04 | 0.340 |
39.37 ± 0.94 | 0.375 |
18.49 ± 0.33 | 2.13 ± 0.07 | 0.050 |
|
GG (75) | 0.18 ± 0.05 | 39.17 ± 0.88 | 18.58 ± 0.35 | 2.11 ± 0.07 | ||||||
CC (43) | 0.18 ± 0.03 | 39.26 ± 0.96 | 18.50 ± 0.36 | 2.12 ± 0.08 | ||||||
rs1784418 | CT (62) | 0.19 ± 0.05 | 0.066 |
39.28 ± 0.86 | 0.944 |
18.57 ± 0.37 | 0.291 |
2.12 ± 0.07 | 0.807 |
|
TT (25) | 0.17 ± 0.05 | 39.21 ± 0.87 | 18.45 ± 0.28 | 2.13 ± 0.06 | ||||||
GG (37) | 0.17 ± 0.04 | 39.07 ± 0.86 | 18.56 ± 0.35 | 2.11 ± 0.07 | ||||||
rs1612069 | GT (70) | 0.19 ± 0.05 | 0.152 |
39.44 ± 0.88 | 18.54 ± 0.37 | 0.469 |
2.13 ± 0.07 | 0.265 |
||
TT (21) | 0.18 ± 0.03 | 38.97 ± 0.94 | 18.45 ± 0.30 | 2.11 ± 0.07 | ||||||
CC (95) | 0.18 ± 0.05 | 39.31 ± 0.92 | 18.54 ± 0.32 | 2.12 ± 0.07 | ||||||
TUFT1 | rs16833391 | CT (32) | 0.17 ± 0.03 | 0.216 |
39.14 ± 0.82 | 0.638 |
18.47 ± 0.45 | 0.452 |
2.12 ± 0.08 | 0.938 |
TT (2) | 0.19 ± 0.01 | 39.40 ± 1.16 | 18.74 ± 0.03 | 2.10 ± 0.07 | ||||||
AA (21) | 0.18 ± 0.05 | 39.12 ± 0.79 | 18.59 ± 0.38 | 2.11 ± 0.07 | ||||||
rs6587597 | AG (70) | 0.18 ± 0.04 | 0.848 |
39.20 ± 0.91 | 0.324 |
18.53 ± 0.34 | 0.461 |
2.12 ± 0.07 | 0.231 |
|
GG (38) | 0.18 ± 0.04 | 39.43 ± 0.91 | 18.48 ± 0.36 | 2.14 ± 0.07 | ||||||
AA (60) | 0.18 ± 0.04 | 39.33 ± 0.89 | 18.47 ± 0.35 | 2.13 ± 0.07 | ||||||
rs17640579 | AG (54) | 0.18 ± 0.05 | 0.893 |
39.20 ± 0.93 | 0.739 |
18.55 ± 0.36 | 0.127 |
2.11 ± 0.07 | 0.282 |
|
GG (15) | 0.19 ± 0.06 | 39.23 ± 0.84 | 18.67 ± 0.33 | 2.10 ± 0.07 | ||||||
AA (5) | 0.16 ± 0.05 | 39.12 ± 0.86 | 18.49 ± 0.29 | 2.12 ± 0.06 | ||||||
rs12749 | AG (44) | 0.17 ± 0.04 | 0.184 |
39.26 ± 0.80 | 0.931 |
18.49 ± 0.41 | 0.652 |
2.12 ± 0.07 | 0.880 |
|
GG (80) | 0.19 ± 0.05 | 39.28 ± 0.95 | 18.55 ± 0.35 | 2.12 ± 0.07 | ||||||
AA (12) | 0.17 ± 0.05 | 39.29 ± 0.85 | 18.43 ± 0.46 | 2.13 ± 0.08 | ||||||
rs3790506 | AG (63) | 0.18 ± 0.05 | 0.521 |
39.21 ± 0.88 | 0.790 |
18.57 ± 0.33 | 0.382 |
2.11 ± 0.07 | 0.481 |
|
GG (54) | 0.18 ± 0.04 | 39.32 ± 0.93 | 18.50 ± 0.36 | 2.13 ± 0.07 |
Table
Summary of the lesion depth and loss of mineral comparisons by genotype.
CC (83) | 194.2 ± 9.6 | 49.13 ± 5.51 | ||||
AMELX | rs946252 | CT (67) | 195.1 ± 11.8 | 0.49 |
49.87 ± 5.94 | 0.67 |
TT (60) | 196.3 ± 10.4 | 49.10 ± 5.14 | ||||
TT (76) | 194.9 ± 10.1 | 50.26 ± 4.92 | ||||
AMBN | rs4694075 | CT (102) | 195.1 ± 11.1 | 0.99 |
49.16 ± 6.02 | 0.16 |
CC (34) | 195.2 ± 9.8 | 48.20 ± 5.03 | ||||
AA (139) | 195.7 ± 10.2 | 49.80 ± 5.24 | ||||
rs7694409 | AG (58) | 193.6 ± 11.1 | 0.34 |
48.32 ± 6.01 | 0.25 |
|
GG (10) | 197.5 ± 10.1 | 49.20 ± 4.70 | ||||
AA (140) | 195.4 ± 10.4 | 49.80 ± 5.33 | ||||
rs13115627 | AG (61) | 194.0 ± 10.8 | 0.64 |
48.72 ± 5.99 | 0.30 |
|
GG (12) | 195.7 ± 10.7 | 48.10 ± 4.88 | ||||
AA (134) | 195.9 ± 9.9 | 49.75 ± 5.89 | ||||
ENAM | rs12640848 | AG (66) | 194.5 ± 11.5 | 49.45 ± 4.29 | ||
GG (12) | 187.9 ± 7.9 | 44.83 ± 5.25 | ||||
GG (16) | 191.8 ± 7.9 | 49.38 ± 5.67 | ||||
KLK4 | rs198968 | AG (101) | 195.3 ± 10.9 | 0.44 |
49.18 ± 5.29 | 0.85 |
AA (96) | 195.4 ± 10.4 | 49.63 ± 5.75 | ||||
TT (13) | 200.9 ± 12.5 | 53.15 ± 6.81 | ||||
TFIP11 | rs2097470 | CT (73) | 194.8 ± 9.9 | 0.1 |
48.48 ± 5.40 | |
CC (126) | 194.5 ± 10.5 | 49.50 ± 5.29 | ||||
CC (11) | 202.6 ± 13.1 | 54.27 ± 6.10 | ||||
rs134143 | CT (101) | 195.1 ± 10.5 | 49.14 ± 5.45 | |||
TT (100) | 194.2 ± 10.1 | 49.12 ± 5.31 | ||||
AA (17) | 198.9 ± 10.3 | 49.47 ± 5.59 | ||||
MMP20 | rs2292730 | AG (72) | 194.4 ± 9.7 | 0.283 |
48.46 ± 5.66 | 0.22 |
GG (122) | 195.0 ± 11.0 | 49.38 ± 5.52 | ||||
CC (66) | 194.3 ± 10.7 | 48.60 ± 5.30 | ||||
rs1784418 | CT (103) | 195.3 ± 10.4 | 0.750 |
49.73 ± 5.26 | 0.39 |
|
TT (44) | 195.5 ± 10.6 | 49.80 ± 6.33 | ||||
GG (58) | 197.7 ± 10.0 | 49.05 ± 6.03 | ||||
rs1612069 | GT (109) | 193.6 ± 9.6 | 49.72 ± 5.11 | 0.62 |
||
TT (43) | 196.1 ± 9.6 | 48.93 ± 5.81 | ||||
GG (64) | 194.9 ± 10.7 | 48.46 ± 5.27 | ||||
TUFT1 | rs6587597 | AG (112) | 195.6 ± 9.9 | 0.53 |
49.64 ± 5.63 | 0.21 |
AA (36) | 193.4 ± 11.9 | 50.36 ± 5.46 | ||||
CC (152) | 194.9 ± 10.0 | 49.07 ± 5.48 | ||||
rs16833391 | CT (55) | 195.1 ± 11.8 | 0.76 |
50.02 ± 5.45 | 0.26 |
|
TT (5) | 198.4 ± 11.3 | 52.40 ± 7.23 | ||||
GG (21) | 189.8 ± 12.1 | 48.52 ± 4.85 | ||||
rs17640579 | AG (89) | 196.0 ± 9.7 | 50.10 ± 5.82 | 0.29 |
||
AA (102) | 195.4 ± 10.7 | 48.97 ± 5.36 | ||||
GG (128) | 195.1 ± 9.9 | 49.25 ± 5.50 | ||||
rs12749 | AG (73) | 195.2 ± 11.3 | 0.96 |
49.75 ± 5.57 | 0.78 |
|
AA (11) | 194.3 ± 13.0 | 48.82 ± 5.82 | ||||
GG (94) | 196.0 ± 10.8 | 48.99 ± 5.79 | ||||
rs3790506 | AG (95) | 194.9 ± 10.3 | 0.25 |
49.80 ± 5.43 | 0.59 |
|
AA (23) | 191.9 ± 10.1 | 49.30 ± 4.81 |
Comparison of enamel lesion depth by genotype. *Significant difference from the wild genotype.
Comparison of enamel mineral loss by genotype. *Significant difference from the wild genotype.
Previous studies have shown that genetic variations in enamel formation genes influence caries risk (Opal et al.,
Tooth type, tooth surface (buccal or lingual) and post-eruptive enamel maturation are regarded as factors that influence enamel demineralization (Palti et al.,
The demineralization of dental enamel can be quantified by evaluating changes in dental mineral content using a variety of techniques (Bergman and Engfeldt,
Previous studies had shown that microhardness and enamel chemicals, such as calcium and magnesium were related to genetic variations in enamel formation genes (Shimizu et al.,
We also found significant associations between variations in
In our study, individuals with the GG genotype at rs12640848 of
Previous epidemiological studies have reported an association between caries susceptibility and genetic variations at
Tuftelin-interacting protein 11 (
In conclusion, we identified significant associations between genetic variations in
LP contributed to the study conception and design, data acquisition and analysis, and the drafting of the manuscript; YT, LY, and PZ contributed to the data acquisition; QZ contributed to the data analysis and drafting of the manuscript; and HL contributed to the study conception and design, data acquisition and analysis, and manuscript revisions. All authors read and critically revised the manuscript. All authors gave final approval and agreed to be accountable for all aspects of the work.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
We gratefully acknowledge the assistance of the nurses at the Department of Oral and Maxillofacial Surgery at the Hospital of Stomatology of Sun Yat-sen University and the Guangdong Provincial Stomatological Hospital for their assistance during the sample collection process.