# Let‐7e as Potential Diagnostic Biomarkers in Early Detection of Peri‐Implant Diseases: A Cross‐Sectional Study

## TL;DR

This study explores the potential of let-7e microRNA as a biomarker for early detection of peri-implant diseases using fluid samples from around dental implants.

## Contribution

The study identifies let-7e as a novel and consistently detectable biomarker for peri-implant diseases.

## Key findings

- Let-7e expression was eightfold higher in peri-implant mucositis and 94-fold higher in peri-implantitis compared to healthy controls.
- Let-7e was the only miRNA consistently detected across all peri-implant crevicular fluid samples.
- Statistically significant differences in let-7e expression were found between health, mucositis, and implantitis groups.

## Abstract

Peri‐implant diseases (PID), specifically peri‐implant mucositis and peri‐implantitis, significantly jeopardize dental implant success. Traditional diagnostic methods, relying on periodontal probing and radiographs, have limitations in precisely diagnosing these conditions. Recent studies suggest that microRNA (miRNA) profiling might be a breakthrough in the early detection of PID. This study aimed to evaluate the expression levels of specific miRNAs—miR‐98, miR‐145, miR‐146a, and let‐7e—in individuals with peri‐implant mucositis and peri‐implantitis compared to a healthy control.

From January 2022 to October 2023, 19 participants with 38 dental implants were recruited according to established criteria. After clinical and radiographic evaluations, dental implants were grouped as peri‐implant health (Group 1), peri‐implant mucositis (Group 2), and peri‐implantitis (Group 3). Subsequently, peri‐implant crevicular fluid (PICF) samples were collected and analyzed through real‐time quantitative polymerase chain reaction (qPCR).

Based on the findings, only let‐7e biomarkers were consistently detected across all samples, with their expression increased eightfold in peri‐implant mucositis and 94‐fold in peri‐implantitis cases. Kruskal–Wallis's test showed a statistically significant difference in relative gene expression of let‐7e between the different groups, H(2) = 25.825, p ≤ 0.001.

Our study indicates that miRNA biomarkers, particularly let‐7e, may play a significant role in the development and progression of PID, highlighting the need for further in‐depth investigation, with PICF offering a practical, noninvasive sampling method.