Abstract
Purpose
Emerging evidence highlights genetic susceptibility as a pivotal factor in the pathogenesis of peri-implantitis. The present study aimed to examine the potential association between the microRNA (miR)-146a rs57095329 polymorphism and susceptibility to peri-implantitis.
Methods
A total of 230 patients with implant-supported dentures free of peri-implantitis and 230 patients diagnosed with peri-implantitis were recruited. Genotyping was performed using the restriction fragment length polymorphism polymerase chain reaction (PCR) technique, and miR-146a expression was analyzed using real-time qualitative PCR. The Hardy–Weinberg equilibrium test was used to confirm whether the genotype distribution matched expected values. Logistic regression analysis was then conducted to identify potential independent risk indicators.
Results
miR-146a expression was significantly higher in the peri-implantitis group, with expression levels following the order: AA genotype > GA genotype > GG genotype. The AA genotype (odds ratio [OR], 2.753; 95% confidence interval [CI], 1.510–5.019; P<0.001) and the A allele (OR, 1.599; 95% CI, 1.220–2.094; P<0.001) were significantly associated with increased peri-implantitis risk. Mutations in the G allele may serve as a protective factor. The AA genotype showed the highest plaque index, and a significant positive correlation was observed between miR-146a expression levels and plaque index. In addition, patients with the AA genotype exhibited poorer periodontal indices and higher tumor necrosis factor-α levels compared with those carrying GG/GA genotypes. Indicators of periodontal health status, miR-146a levels, and the rs57095329 polymorphism may therefore serve as independent risk factors for peri-implantitis.
Conclusions
The miR-146a rs57095329 polymorphism was significantly associated with susceptibility to peri-implantitis.
Keywords: Genetic polymorphism, miR-146a, Peri-implantitis, rs57095329
Graphical Abstract
INTRODUCTION
Dental implantation has become the primary approach for restoring dentition defects and replacing missing teeth. Despite considerable advancements in materials, technology, and implant surface design, implant failure still occurs in certain cases [1]. Peri-implantitis is recognized as a chronic, progressive marginal inflammation that can lead to resorption of supporting bone tissue, resulting in implant loosening or eventual failure [2]. Its development involves the synergistic action of several complex factors, including pathogenic bacterial infection, host susceptibility, biomechanical stress, and personal habits [3]. Moreover, research has demonstrated a correlation between peri-implantitis and gene polymorphisms, with genetic susceptibility emerging as a critical factor for both periodontitis and peri-implantitis [4]. However, the exact mechanisms underlying peri-implantitis remain incompletely understood. The identification of reliable biomarkers could provide novel strategies for prevention and treatment.
MicroRNAs (miRs) play essential roles in various biological processes, including protein transcription, osteoclastogenesis, immune regulation, and the innate immune response [5]. They also mediate interactions between peri-implant tissues and the surrounding environment in peri-implantitis [6,7]. Importantly, miR-146a expression in the venous blood of peri-implantitis patients differs significantly from that in periodontitis patients and healthy individuals [8]. A case-control study confirmed that miR-146a expression is significantly elevated in peri-implantitis [9]. miR-146a exhibits anti-inflammatory properties, and its upregulation may represent a compensatory mechanism that regulates inflammation and tissue destruction, thereby limiting damage to connective tissue and alveolar bone [10]. The single-nucleotide polymorphism (SNP) rs57095329 is located approximately 17 kb upstream of the pre-miR-146a sequence in the promoter region [11]. Recent studies have linked rs57095329 to susceptibility to gout [12] and certain autoimmune diseases [13]. On the basis of these findings, we hypothesized that the miR-146a rs57095329 polymorphism may be associated with peri-implantitis pathogenesis.
The present study aimed to evaluate the association between the miR-146a rs57095329 polymorphism and peri-implantitis susceptibility by comparing miR-146a expression levels across groups, analyzing rs57095329 genotype distributions, and identifying potential risk factors for peri-implantitis. This investigation was expected to provide a scientific foundation for the prevention and treatment of peri-implantitis.
MATERIALS AND METHODS
Ethical approval of studies and informed consent
This study was approved by the Ethics Committee of The Third People’s Hospital of Cangnan County (approval number: 2021310). Written informed consent was obtained from all participants before enrollment. All procedures were conducted in accordance with the principles of the Declaration of Helsinki.
Study objects
A total of 460 patients who underwent implant-supported denture restoration at the Department of Implantology of The Third People’s Hospital of Cangnan County were recruited. All participants received single-implant crown restorations rather than bridge or full-mouth rehabilitations, and all prostheses were screw-retained. The duration of restoration was at least 12 months. Patients were provided with standardized oral hygiene instructions, including the Bass brushing technique and flossing. None of the participants had received professional maintenance procedures in the 6 months prior to the study. Based on the presence or absence of peri-implantitis, the study population was divided into 2 groups: the peri-implantitis group, which included 230 patients, and the control group, which also included 230 patients. If any implant of a patient was affected by peri-implantitis, the patient was assigned to the peri-implantitis group. All participants had received at least 1 dental implant and had completed the restoration process for at least 1 year. For the peri-implantitis group, diagnostic criteria were based on established definitions [14]: bleeding on probing around the implant, possibly with purulent exudation; probing pocket depth (PPD, defined as the vertical measurement from the gingival margin to the base of the periodontal pocket during clinical probing) ≥4 mm; and radiographic evidence of bone resorption around the implant. The control group was defined by the following criteria: implant presence without peri-implant mucositis, peri-implantitis, or other inflammatory disease, with PPD <3 mm and no radiographic evidence of bone resorption.
The exclusion criteria were as follows: patients with severe cardiovascular, hematological, or autoimmune diseases; those who had used immunosuppressive agents or antibiotics within the past 3 months; individuals undergoing orthodontic treatment; patients with hepatitis, diabetes, a history of peri-implant mucositis, or other chronic systemic conditions; pregnant or breastfeeding women; and patients with incomplete clinical data or non-compliance.
Sample collection
For patients diagnosed with peri-implantitis, 5 mL of fasting venous blood was collected from the arm in the early morning within 24 hours of diagnosis. Samples were transferred immediately to ethylenediaminetetraacetic acid anticoagulant tubes, centrifuged, and stored at −80°C until analysis. For participants without peri-implantitis, fasting venous blood was similarly collected in the early morning after informed consent was obtained.
Bone resorption measurement
All patients underwent cone-beam computed tomography scans immediately after implant restoration and again 6 months postoperatively. Images were processed and analyzed using Planmeca Remexis software to measure alveolar ridge height [15], defined as the vertical distance from the apical region of the implant to its coronal margin. The reduction in this height over time was quantified as bone resorption volume.
Periodontal status was assessed using clinical indices, including gingival index, plaque index, gingival condition, peri-implant condition, bone resorption volume, and sulcus bleeding index (SBI). The SBI is used to assess bleeding on the posterior gingiva after probing (rated 0–4) and reflects inflammatory activity of soft tissues around the implant. Higher scores indicate greater inflammation. All measurements were performed by trained professionals using standardized protocols, and operators underwent routine calibration to ensure consistency. Detailed calibration records were maintained to guarantee the reliability of measurements.
Genotyping
Genomic DNA was extracted using the Gentra Puregene Blood Kit (Qiagen, Hilden, Germany) restriction fragment length polymorphism polymerase chain reaction (PCR) [16] was performed to analyze miR-146a polymorphisms. PCR products were digested with the MspI restriction endonuclease. The resulting fragment lengths were: 160 bp for the AA genotype; 160, 143, and 17 bp for the AG genotype; and 143 and 17 bp for the GG genotype.
Quantification of the expression level of miR-146a
Total RNA was extracted using TRIzol reagent, and reverse transcription into complementary DNA (cDNA) was carried out with the miScript II RT Kit (Qiagen LLC, Germantown, MD, USA). Using cDNA as the template, real-time qualitative PCR amplification was performed with the miScript SYBR Green PCR Kit (catalog number: 218073). Small nuclear RNA U6 was used as the internal reference, and relative miR-146a expression was calculated using the 2−ΔΔCt method.
Statistical analysis
Statistical analyses were performed using SPSS version 21 (IBM Corp., Armonk, NY, USA) and GraphPad Prism 9 (GraphPad Software Inc., San Diego, CA, USA). Comparisons between 2 groups were conducted with the independent samples t-test, while 1-way analysis of variance was applied for comparisons among multiple groups when appropriate. The χ2 test was used to assess differences in allele frequencies and genotype distributions. Hardy–Weinberg equilibrium testing was performed to verify whether observed genotype distributions matched expected values. Logistic regression analysis was used to identify independent risk factors associated with peri-implantitis. Potential confounding variables, such as age, sex, and smoking status, were included in the model. Multicollinearity was assessed by calculating variance inflation factors (VIF). Factor-reduction-based multivariate analysis was applied to evaluate possible interactions among tumor necrosis factor (TNF)-α, interleukin (IL)-6, and rs57095329. Pearson correlation analysis was conducted to determine associations between relative miR-146a expression levels and the plaque index. A P value <0.05 was considered statistically significant.
RESULTS
General clinical information for subjects
A comparison of the general clinical characteristics of the study participants is presented in Table 1. Among the 230 subjects in the control group and the 230 in the peri-implantitis group, no significant differences were observed with respect to age, sex, body mass index (BMI), drinking habits, cause of tooth loss, implant position, or peri-implantitis phenotypes (P>0.05). However, statistically significant differences were found in smoking status, history of periodontitis, frequency of tooth brushing, daily use of dental floss, and daily mouth rinsing (P<0.05). With respect to inflammatory factors, the peri-implantitis group exhibited significantly higher levels of TNF-α and IL-6 compared with the control group (P<0.001). Furthermore, periodontal condition indicators—including the gingival index, plaque index, calculus index, PPD, clinical attachment level (CAL, defined as the vertical distance from the cementoenamel junction or the margin of the implant crown to the base of the probing depth), SBI, gingival crevicular fluid volume, and degree of bone resorption—were all markedly elevated in the peri-implantitis group relative to controls (P<0.001).
Table 1. Comparative analysis of general clinical information.
| Items | Control group (n=230) | Peri-implantitis group (n=230) | P value | |
|---|---|---|---|---|
| Age (yr) | 28.37±3.29 | 28.64±3.13 | 0.367 | |
| Sex | 0.779 | |||
| Male | 119 (51.74) | 122 (53.04) | ||
| Female | 111 (48.26) | 108 (46.96) | ||
| BMI (kg/m2) | 22.35±2.72 | 22.44±2.51 | 0.692 | |
| Drinking (yes) | 91 (39.57) | 94 (40.87) | 0.775 | |
| Smoking (yes) | 79 (34.35) | 101 (43.91) | 0.036* | |
| Periodontitis | 99 (43.04) | 121 (52.61) | 0.040* | |
| Reasons for tooth loss | 0.082 | |||
| Periodontitis | 96 (41.74) | 119 (51.74) | ||
| Deep caries | 4 (1.74) | 5 (2.17) | ||
| Trauma | 130 (56.52) | 106 (46.09) | ||
| Planting position | 0.093 | |||
| Anterior region | 168 (73.04) | 155 (67.39) | ||
| Posterior region | 62 (26.96) | 75 (32.61) | ||
| Per-implant phenotype | 0.062 | |||
| Thin | 126 (54.78) | 106 (46.09) | ||
| Thick | 104 (45.22) | 124 (53.91) | ||
| Brush teeth daily | 0.041* | |||
| ≤3 | 180 (78.26) | 197 (85.65) | ||
| >3 | 50 (21.74) | 33 (14.35) | ||
| Use dental floss every day | 0.048* | |||
| Yes | 108 (46.96) | 87 (37.83) | ||
| No | 122 (53.04) | 143 (62.17) | ||
| Daily mouth rinsing | 0.046* | |||
| Yes | 104 (45.22) | 83 (36.09) | ||
| No | 126 (54.78) | 147 (63.91) | ||
| TNF-α (ng/mL) | 12.08±2.25 | 15.58±2.09 | <0.001*** | |
| IL-6 (ng/mL) | 25.42±3.31 | 29.07±3.09 | <0.001*** | |
| Periodontal status | ||||
| Gingival index | 0.58±0.30 | 2.37±0.59 | <0.001*** | |
| PPD (mm) | 1.83±0.57 | 5.38±0.81 | <0.001*** | |
| Plaque index | 0.92±0.40 | 2.21±0.71 | <0.001*** | |
| CAL (mm) | 1.29±0.53 | 4.39±0.78 | <0.001*** | |
| SBI | 0.94±0.12 | 3.53±0.89 | <0.001*** | |
| Calculus index | 0.23±0.16 | 0.56±0.25 | <0.001*** | |
| Gingival crevicular fluid volume (μL) | 0.86±0.25 | 1.94±0.25 | <0.001*** | |
| Bone resorption (mm) | 1.43±0.29 | 2.75±0.30 | <0.001*** | |
Values are presented as mean ± standard deviation or number (%).
BMI: body mass index, TNF-α: tumor necrosis factor-α, IL-6: interleukin-6, PPD: probing pocket depth, CAL: clinical attachment level, SBI: sulcus bleeding index.
*P<0.05, ***P<0.001.
The expression of miR-146a may be associated with peri-implantitis
The relative expression level of miR-146a in the peri-implantitis group was significantly higher than that in the control group (Figure 1A). Analysis of relative expression levels across different genotypes (GG, GA, AA) showed that in the control group, expression was similar among all 3 genotypes. In contrast, within the peri-implantitis group, the AA genotype exhibited the highest expression of miR-146a, followed by GA, with the lowest expression observed in GG (Figure 1B). In the control group, plaque index values did not differ significantly among genotypes. In the peri-implantitis group, plaque index scores were significantly higher across all genotypes compared with controls, with the AA genotype showing the highest values (Figure 1C). A significant positive correlation was also identified between miR-146a expression and plaque index (r=0.6484; P<0.0001) (Figure 1D).
Figure 1. Association of miR-146a expression and rs57095329 genetic polymorphism with peri-Implantitis and plaque index. (A) The relative expression levels of miR-146a among different groups were measured using RT-qPCR. (B) The relative expression levels of miR-146a across different genotypes within each group were assessed by RT-qPCR. (C) The plaque index was compared between the control group and the periodontitis group, stratified by genotype. (D) Correlation analysis between miR-146a relative expression levels and the plaque index.
miR: microRNA, RT-qPCR: real-time qualitative polymerase chain reaction, ns: no statistical significance.
*P<0.05, ***P<0.001.
The association between rs57095329 polymorphism and peri-implantitis susceptibility
The frequency of the GG and GA genotypes was lower in the peri-implantitis group, whereas the frequency of the AA genotype was higher. The AA genotype was significantly associated with an increased risk of peri-implantitis (odds ratio [OR], 2.753; 95% confidence interval [CI], 1.510–5.019; P<0.001). Conversely, the GG or GA genotypes were associated with a reduced risk (OR, 1.856; 95% CI, 1.030–3.343; P=0.038). Under the dominant model, the AA genotype was significantly more frequent in the peri-implantitis group (OR, 1.699; 95% CI, 1.165–2.477; P=0.006), while the combined GG+GA genotype frequency was lower. Under the recessive model, the combined GA+AA frequency was higher in the peri-implantitis group (OR, 2.223; 95% CI, 1.270–3.891; P=0.004), whereas the GG genotype was less frequent. At the allelic level, the A allele was significantly more frequent in the peri-implantitis group (OR, 1.599; 95% CI, 1.220–2.094; P<0.001), while the G allele was less common. After adjusting for age and sex, the GA genotype remained significantly associated with peri-implantitis (P=0.033), although the association became marginally significant after further adjustment for smoking (P=0.052). By contrast, the association between the AA genotype and peri-implantitis remained robust after adjusting for age, sex, and smoking (P=0.002 and P=0.003, respectively), indicating that the AA genotype may serve as an independent risk factor. The PHWE values for the control and peri-implantitis groups were 0.857 and 0.571, respectively, supporting representativeness of the samples (Table 2).
Table 2. Correlation of the miR-146a rs57095329 polymorphism with peri-implantitis.
| Items | Control group (n=230) | Peri-implantitis group (n=230) | χ2 | P value | OR (95% CI) | P valuea) | OR (95% CI)a) | P valueb) | OR (95% CI)b) | |
|---|---|---|---|---|---|---|---|---|---|---|
| Codominant model | ||||||||||
| GG | 42 (18.26) | 21 (9.13) | - | - | 1 | |||||
| GA | 111 (48.26) | 103 (44.78) | 4.310 | 0.038* | 1.856 (1.030–3.343) | 0.033* | 1.904 (1.053–3.443) | 0.052 | 1.805 (0.994–3.278) | |
| AA | 77 (33.48) | 106 (46.09) | 11.347 | <0.001*** | 2.753 (1.510–5.019) | <0.001*** | 2.781 (1.521–4.083) | 0.002** | 2.640 (1.438–4.845) | |
| Dominant model | ||||||||||
| GG+GA | 153 (66.52) | 124 (53.91) | - | - | 1 | |||||
| AA | 77 (33.48) | 106 (46.09) | 7.632 | 0.006** | 1.699 (1.165–2.477) | 0.006** | 1.698 (1.163–2.479) | 0.005** | 1.719 (1.714–2.516) | |
| Recessive model | ||||||||||
| GG | 42 (18.26) | 21 (9.13) | - | - | 1 | |||||
| GA+AA | 188 (81.74) | 209 (90.87) | 8.111 | 0.004** | 2.223 (1.270–3.891) | 0.004** | 2.347 (1.318–4.179) | 0.003** | 2.419 (1.354–4.322) | |
| Alleles | ||||||||||
| G | 195 (42.39) | 145 (31.52) | - | - | 1 | |||||
| A | 265 (57.61) | 315 (64.48) | 11.663 | <0.001*** | 1.599 (1.220–2.094) | |||||
| PHWE | 0.857 | 0.571 | ||||||||
miR: microRNA, OR: odds ratio, CI: confidence interval, HWE: Hardy-Weinberg equilibrium.
a)Adjusted by age and sex; b)Adjusted by age, sex, and smoking.
*P<0.05, **P<0.01, ***P<0.001.
Periodontal conditions and the miR-146a rs57095329 polymorphism
Patients were classified into 2 groups according to genotype: GG/GA (n=124) and AA (n=106). Comparative analysis revealed that TNF-α levels in the GG/GA group were significantly lower than those in the AA group (P<0.001). However, IL-6 levels did not differ significantly between groups (P=0.321). Among periodontal indicators, gingival index, plaque index, calculus index, PPD, CAL, gingival crevicular fluid volume, and bone resorption were all significantly lower in the GG/GA group compared with the AA group (P<0.05). Collectively, peri-implantitis patients with the AA genotype demonstrated poorer periodontal status and higher TNF-α levels (Table 3).
Table 3. Analysis of miR-146a rs57095329 polymorphism and periodontal status in patients with peri-implantitis.
| Characteristics | GG/GA (n=124) | AA (n=106) | P value |
|---|---|---|---|
| TNF-α (ng/mL) | 14.88±2.12 | 15.98±2.14 | <0.001*** |
| IL-6 (ng/mL) | 28.35±2.99 | 28.74±2.95 | 0.321 |
| Gingival index | 2.17±0.57 | 2.43±0.51 | <0.001*** |
| PPD (mm) | 5.19±0.79 | 5.47±0.83 | 0.012* |
| Plaque index | 2.00±0.72 | 2.22±0.71 | 0.025* |
| CAL (mm) | 4.14±0.70 | 4.50±0.81 | <0.001*** |
| SBI | 3.41±0.87 | 3.59±0.89 | 0.115 |
| Calculus index | 0.36±0.24 | 0.79±0.25 | <0.001*** |
| Gingival crevicular fluid volume (μL) | 1.84±0.23 | 1.97±0.30 | <0.001*** |
| Bone resorption (mm) | 2.63±0.31 | 2.73±0.32 | 0.027* |
miR: microRNA, TNF-α: tumor necrosis factor-α, IL-6: interleukin-6, PPD: probing pocket depth, CAL: clinical attachment level, SBI: sulcus bleeding index.
*P<0.05, ***P<0.001.
Possible independent risk indicators affecting the occurrence of peri-implantitis
To ensure the reliability of the statistical analysis, VIF testing was performed to assess multicollinearity among independent variables. All tested variables, including PPD, CAL, plaque index, and calculus index, had VIF values below 5, indicating no significant multicollinearity. Multi-factor dimensionality reduction analyses were conducted for TNF-α with rs57095329 and IL-6 with rs57095329. Bartlett test results yielded P values >0.05 in all cases, indicating no significant interaction effects. Logistic regression analysis demonstrated that smoking, history of periodontitis, frequency of daily tooth brushing, daily flossing, daily mouthwash use, plaque index, calculus index, PPD, CAL, gingival crevicular fluid volume, degree of bone resorption, miR-146a levels, and rs57095329 polymorphism were all significant independent risk indicators for peri-implantitis (P<0.05). By contrast, TNF-α, IL-6, gingival index, and SBI were not significantly associated with peri-implantitis (P>0.05) (Table 4). Multivariate analysis further identified PPD, gingival crevicular fluid volume, miR-146a expression, and rs57095329 polymorphism as independent risk factors. After adjusting for confounding variables, associations of the other factors were no longer statistically significant.
Table 4. Logistic regression analysis of risk factors associated with peri-implantitis.
| Characteristics | Univariate regression analysis | Multivariate regression analysis | ||||
|---|---|---|---|---|---|---|
| OR | 95% CI | P value | OR | 95% CI | P value | |
| Age | 1.425 | 0.984–2.062 | 0.061 | |||
| Sex | 1.054 | 0.731–1.591 | 0.779 | |||
| Smoking | 1.497 | 1.027–2.181 | 0.036* | 1.290 | 0.834–1.996 | 0.253 |
| Periodontitis | 1.469 | 1.017–2.121 | 0.040* | 1.382 | 0.905–2.111 | 0.134 |
| Brush teeth daily | 1.658 | 1.022–2.690 | 0.040* | 1.598 | 0.946–2.699 | 0.080 |
| Use dental floss every day | 1.455 | 1.003–2.110 | 0.048* | 1.553 | 0.316–7.635 | 0.588 |
| Daily mouth rinsing | 1.462 | 1.006–2.125 | 0.047* | 1.073 | 0.216–5.325 | 0.932 |
| TNF-α | 1.345 | 0.932–1.941 | 0.113 | |||
| IL-6 | 1.276 | 0.885–1.841 | 0.192 | |||
| Gingival index | 1.299 | 0.900–1.837 | 0.162 | |||
| PPD | 1.576 | 1.090–2.277 | 0.015* | 1.545 | 1.042–2.290 | 0.030* |
| Plaque index | 1.520 | 1.053–2.196 | 0.025* | 1.370 | 0.928–2.023 | 0.114 |
| CAL | 1.494 | 1.035–2.157 | 0.032* | 1.421 | 0.959–2.106 | 0.080 |
| SBI | 1.393 | 0.965–2.010 | 0.077 | |||
| Calculus index | 1.494 | 1.035–2.158 | 0.032* | 1.341 | 0.901–1.994 | 0.148 |
| Gingival crevicular fluid volume | 1.548 | 1.071–2.236 | 0.020* | 1.489 | 1.001–2.213 | 0.049* |
| Bone resorption | 1.523 | 1.054–2.201 | 0.025* | 1.399 | 0.947–2.068 | 0.092 |
| miR-146a | 1.623 | 1.129–2.358 | 0.009** | 1.612 | 1.088–2.389 | 0.017* |
| rs57095329 | 1.699 | 1.165–2.477 | 0.006** | 1.813 | 1.212–2.711 | 0.004** |
OR: odds ratio, CI: confidence interval, TNF-α: tumor necrosis factor-α, IL-6: interleukin-6, PPD: probing pocket depth, CAL: clinical attachment level, SBI: sulcus bleeding index.
*P<0.05, **P<0.01.
DISCUSSION
Peri-implantitis can lead to progressive resorption of bone tissue surrounding implants, ultimately resulting in implant instability or failure [17]. Previous studies have demonstrated that genetic polymorphisms are associated with susceptibility to peri-implantitis [18,19]. For example, miR-146a (rs2910146) and miR-499 (rs3746444) have been identified as potential genetic factors contributing to increased peri-implantitis risk in Iranian populations [8]. In the present study, which included 230 patients with peri-implantitis and 230 controls, we systematically investigated for the first time the association between the miR-146a rs57095329 polymorphism and peri-implantitis susceptibility. Our findings suggest that this polymorphism may play a role in the development of peri-implantitis.
Patients with a history of smoking or periodontitis exhibit a substantially increased risk of peri-implantitis [20,21]. In our study, we confirmed that smoking and poor oral hygiene habits were associated with greater accumulation of dental plaque and calculus, thereby contributing to an elevated peri-implantitis risk. Previous research has shown that IL-6 expression is markedly increased in peri-implantitis patients [22]. Our results indicated that both TNF-α and IL-6 may exacerbate peri-implantitis progression. Moreover, we observed significant differences in plaque index across different genotypes of the miR-146a rs57095329 polymorphism, with the AA genotype showing the highest plaque index. Expression levels of miR-146a were also significantly elevated in this genotype, strongly correlating with peri-implantitis susceptibility. Furthermore, a significant positive correlation was identified between plaque index and miR-146a expression, suggesting that miR-146a may contribute to peri-implantitis initiation and progression by enhancing host susceptibility to plaque accumulation.
Significant differences in genotype frequencies were found between the peri-implantitis and control groups. The AA genotype appears to represent an important risk factor, whereas the GG and GA genotypes may provide some protective effect. These results are consistent with prior studies. For instance, the AA genotype and A allele have been associated with oral ulcers [23], and gout patients with the G genotype exhibit a 0.362-fold lower risk of tophi compared with those carrying the AA genotype [12]. Similarly, the rs57095329 A allele has been identified as a risk factor for coronary artery lesions [24]. In the subgroup analysis comparing GG/GA (n=124) and AA (n=106), patients with the AA genotype demonstrated more severe inflammation and greater periodontal tissue destruction. These findings suggest that the AA genotype substantially influences susceptibility to peri-implantitis. In the future, personalized prevention and treatment strategies may be developed for peri-implantitis patients carrying the AA genotype.
Smoking and periodontitis remain important risk indicators for peri-implantitis [25,26]. Our analysis also identified oral hygiene practices (e.g., daily tooth brushing, flossing, and mouthwash use), periodontal health indicators (e.g., plaque index, calculus index, PPD, CAL, gingival crevicular fluid volume, and extent of bone resorption), and gene-related factors (e.g., miR-146a expression and rs57095329 polymorphism) as independent risk indicators. Following multivariate regression analysis, PPD, gingival crevicular fluid volume, miR-146a expression, and rs57095329 polymorphism were confirmed as independent risk factors for peri-implantitis. These findings emphasize the importance of reinforcing oral hygiene education, systematically evaluating a patient’s history of periodontitis, and tailoring interventions according to genetic risk profiles.
Elevated miR-146a expression has also been reported in unstable angina pectoris [27], multiple sclerosis [28], and periodontitis [10]. Our study confirmed that relative expression levels of miR-146a were significantly higher in peri-implantitis patients. Under healthy conditions, genetic polymorphisms exert minimal influence on miR-146a expression. However, in peri-implantitis patients, expression was highest in the AA genotype, intermediate in the GA genotype, and lowest in the GG genotype. These results suggest that the rs57095329 polymorphism may significantly affect miR-146a expression during peri-implantitis onset. We hypothesize that the AA genotype contributes to disease pathogenesis by promoting elevated miR-146a expression, whereas the GG genotype, associated with relatively low expression, may provide protective effects against peri-implantitis.
The clinical implications of this study are as follows. Patients with peri-implantitis who carry the miR-146a rs57095329 AA genotype may represent a high-risk subgroup for developing severe or recurrent disease. These individuals should be considered for targeted and intensified preventive strategies. For such patients, it may be advisable to shorten the professional maintenance interval from the standard 6 to 3 months to enable early detection of inflammatory signs. Concurrently, tailored oral hygiene instructions should be emphasized, such as guiding patients in the use of interdental brushes in combination with water flossers to improve plaque removal efficacy. In addition, targeted professional maintenance protocols—such as routine subgingival scaling and root planing—can be implemented to minimize biofilm accumulation around implants, thereby facilitating more effective preventive and interventional measures. Furthermore, miR-146a expression levels may serve as a potential biomarker for early detection of inflammatory activity. Regular monitoring of its expression could assist in identifying early signs of disease onset or exacerbation. Looking forward, the development of rapid genetic screening tools for this polymorphism, when integrated with clinical assessments of oral hygiene and inflammatory markers, may support personalized strategies for prevention and intervention.
This study has several limitations that warrant consideration. First, the relatively modest sample size, coupled with its restriction to a regional cohort, may limit the generalizability of the findings. Specifically, all participants were recruited from a single population in Cangnan County, China, which constrains the applicability of results to other ethnic or geographic groups. Genetic polymorphisms such as miR-146a rs57095329 are known to exhibit inter-ethnic variability due to evolutionary and environmental influences. Therefore, the observed association between rs57095329 and peri-implantitis susceptibility should be interpreted cautiously when extrapolated beyond the studied cohort. Multi-ethnic and multi-regional cohort studies are required to validate these findings and to investigate potential ethnicity-specific patterns. Second, this study did not confirm the direct regulation of miR-146a transcription by rs57095329 through functional experiments. This represents another important limitation. Future research should aim to increase sample size, extend analyses beyond single regions, and incorporate diverse populations to achieve a more comprehensive assessment of the potential association between the miR-146a rs57095329 polymorphism and peri-implantitis susceptibility. Moreover, subsequent studies should explore the functional impact of this SNP using methods such as promoter activity assays (e.g., luciferase reporter gene assay) and CRISPR/Cas9 gene editing. Such investigations would provide essential evidence for clarifying the underlying biological mechanisms.
In conclusion, a significant association was identified between the miR-146a rs57095329 polymorphism and peri-implantitis. The AA genotype may contribute to disease progression by promoting elevated miR-146a expression, whereas the GG genotype, associated with comparatively lower miR-146a expression, may attenuate inflammatory responses and confer relative protection against peri-implantitis.
Footnotes
Conflict of Interest: No potential conflict of interest relevant to this article was reported.
- Conceptualization: Tao Yu, Feng Tian, Yuntong Yang.
- Formal analysis: Tao Yu, Feng Tian, Yuntong Yang.
- Investigation: Tao Yu, Feng Tian.
- Methodology: Tao Yu, Feng Tian, Yuntong Yang.
- Project administration: Yuntong Yang.
- Writing - original draft: Tao Yu, Feng Tian.
- Writing - review & editing: Yuntong Yang.
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