Mini-implants have undeniable advantages in Orthodontics. However, the use of mini-implants shows some limitations and disadvantages related to patient age, the quality of the bone tissue, the characteristics of the oral mucosa, implant site, the state of health of the organism and the quality of oral hygiene. The aim of this paper was to analyze the rejection rate of mini-implants in teenage patients, depending on their insertion site, and examine their stability up to three months after insertion. This retrospective study was conducted on dental charts belonging to patients aged between 12 and 17 years, from Oradea, Romania. The mini-implants were placed for various therapeutic reasons and were inserted in the following sites: buccal maxillary area, the infrazygomatic region, palatal area, buccal mandibular area and lingual area; they had a diameter of 1.6 mm (inter-radicular spaces) and of 2 mm (nonbearing tooth areas), and a length of 6–8 mm (mandible) or 8–10 mm (maxilla). The rejection rate was checked in the first month, second month, third month and after the third month from insertion. A total of 432 patients were included in the study, and they had a total of 573 mini-implants. Most implants were placed in the buccal region of the maxilla (27.7%), and most patients had one mini-implant placed (65.7%). The highest rejection rate was obtained in the first month (15.2%). The rejection rate between genders was similar. The mini-implants from the buccal mandibular region had a significantly higher rate of rejection in the first month (M1) in comparison to the mini-implants from the palatal region (24.4% vs. 8.3%). The mini-implants from the lingual region of the mandible had a significantly higher rate of rejection in the second month (M2) in comparison to the mini-implants from the infrazygomatic or the palatal region (10.5% vs. 0%/0%). Mini-implants are very useful for carrying out various orthodontic treatments, but their stability should be enhanced.

Introduction. Anchorage in orthodontics is critical for managing malocclusions, traditionally achieved via intraoral appliances. Temporary Anchorage Devices (TADs) like mini-implants offer enhanced control by being temporarily fixed in bone. These devices, made from materials like titanium and stainless steel, vary in size and are selected based on multiple factors, including patient characteristics and anatomical considerations. This study explores the preferences of Romanian orthodontists concerning mini-implant dimensions and systems, addressing a gap in local data and aiming to align practices with evidence-based standards. Materials and methods. This study employed a questionnaire distributed via social media to Romanian dental professionals from June to September 2024. Data on mini-implant usage, preferences for dimensions, and complications were collected. Ethical approval was secured from the Faculty of Medicine and Pharmacy at the University of Oradea, with participant consent implied through questionnaire completion. Statistical analysis was performed using IBM SPSS, focusing on the correlation between mini-implant dimensions and clinical outcomes. Results. Mini-implants are widely used with preferences for specific dimensions varying by anatomical location. The most common sizes in the maxillary interradicular area were 1.6 x 8 mm and 1.6 x 10 mm. Complications were associated with the use of inappropriate mini-implant sizes, particularly in areas requiring precise dimensional fitting. The study found a notable preference for larger and longer mini-implants in regions like the infrazygomatic area, with a significant portion of orthodontists not using mini-implants in less common locations due to variability in training and resource access. Conclusions. Proper selection of mini-implant sizes is crucial for optimizing clinical outcomes and minimizing complications. The study underscores the importance of comprehensive training and access to diverse mini-implant systems to accommodate varied clinical needs and preferences. Future initiatives should focus on standardizing orthodontic practices in Romania to enhance the success rates of orthodontic treatments involving TADs.