Periodontal Effects of Orthodontic Mini-Screws

Overview

Orthodontic mini-screws (TADs) are commonly used to provide temporary anchorage and prevent unwanted tooth movement during orthodontic treatment. Their clinical success largely depends on their ability to remain stable under functional orthodontic loads. Stability is assessed in two phases: primary stability, which reflects immediate mechanical retention in bone, and secondary stability, which results from biological remodeling and healing over time. Multiple factors such as age, gender, bone characteristics, screw dimensions, and force magnitude may influence screw stability. Recent studies suggest that local inflammation around mini-screws, similar to peri-implantitis in dental implants, can compromise bone integrity and lead to screw failure. Inadequate oral hygiene and the absence of keratinized tissue at the insertion site are among the key risk factors associated with inflammation and soft tissue complications. Unlike traditional implants, mini-screws are often inserted at variable intraoral locations and subject to angular force vectors, which may further impact surrounding periodontal tissues. This cross-sectional clinical study aims to evaluate the effects of orthodontic mini-screw placement on general oral health and periodontal tissue status. The study will investigate site-specific and full-mouth periodontal parameters and explore potential associations between mini-screw stability, soft tissue characteristics, and signs of mucosal inflammation.

Orthodontic mini-screws, also known as temporary anchorage devices (TADs), have become an integral component of modern orthodontic therapy, enabling controlled tooth movement without relying on patient compliance. For optimal clinical success, these devices must maintain mechanical stability throughout the treatment period. Stability is commonly categorized into two types: primary stability, which represents the initial mechanical engagement of the screw with cortical bone, and secondary stability, which depends on bone remodeling and healing processes occurring over time. Despite their clinical utility, mini-screws are prone to several biological and mechanical challenges that may compromise their stability. Factors such as patient age, gender, cortical bone thickness, screw dimensions, insertion torque, and the magnitude and direction of orthodontic forces are known to affect outcomes. Moreover, local inflammatory responses-particularly in the presence of poor oral hygiene or non-keratinized soft tissue-can lead to tissue breakdown and mini-screw failure. These inflammatory reactions resemble peri-implantitis observed in dental implants and are thought to result in marginal bone loss, especially around the neck of the mini-screw. Given the biomechanical complexity and variability in intraoral placement, orthodontic mini-screws may provoke localized periodontal changes, even in periodontally healthy individuals. However, limited data are available on how these devices influence surrounding periodontal tissues at both the site level and full-mouth level, particularly during the early healing phase after placement. This cross-sectional clinical study aims to evaluate the relationship between orthodontic mini-screws and periodontal health three months after screw placement. A total of 132 systemically healthy, non-smoking patients with 160 mini-screw insertions will be included. Clinical parameters such as plaque index (PI), gingival index (GI), probing pocket depth (PPD), recession depth (RD), bleeding on probing (BOP), keratinized tissue width (KTW), supracrestal tissue height (STH), transmucosal soft tissue thickness (phenotype), mucosal redness (MR), and mucosal discomfort (MD) will be measured both site-specifically and at the full-mouth level. In addition, torque gauge (TG) measurements will be used to assess mechanical stability of the mini-screws. The study aims to identify whether site-specific inflammation and soft tissue characteristics correlate with decreased implant stability or patient-reported discomfort. Results may provide valuable insights into the biological response of periodontal tissues to TADs and help improve clinical protocols for their placement, monitoring, and maintenance.