# 3D-Printed Accessories and Auxiliaries in Orthodontic Treatment
## 3 Results  
A systematic search of PubMed and Google Scholar was conducted using specific keywords and a date range from 2020 to 2024, as described in the materials and methods section. This initial search yielded a total of 582 publications, with 143 articles from PubMed and 439 articles from Google Scholar. Only articles published in English that focused on orthodontics and 3D printing were retained, based on a preliminary examination of article titles. This filtering step reduced the pool to 239 articles. After duplicates were excluded, 153 unique articles remained for further screening.  
A detailed assessment of abstracts and, where necessary, full texts was then performed to exclude studies focused on aspects outside the intended scope. This refined the selection to a final count of 75 articles based on their relevance to the focus of this review, which includes advancements in 3D printing technologies in orthodontics and their application in the design and manufacturing of orthodontic accessories and appliances for intraoral use. Out of the 75 articles included in the review, 25 original articles were retrieved from PubMed and 17 were identified through Google Scholar. The remaining articles were found to overlap across both databases, demonstrating the complementary nature of these search tools in capturing the relevant literature. Figure 3 provides a detailed overview of the study selection process conducted for this review.  
The articles included in our study cover a range of orthodontic devices and their applications, with each study focusing on specific categories of devices and orthodontic techniques. The breakdown of device types and the number of articles studying each is as follows in Figure 4.  
We grouped reviewed articles into the following categories: Original Research and Experimental Studies, Clinical Studies and Related Designs, Case Reports and Case Studies, Reviews, and Technical and Methodological Notes. This categorization, by clustering articles with similar goals, reflects their distinct purposes, methodologies, and contributions to the scientific field. The number of articles in each category is described in Figure 5.  
In the reviewed articles, it was possible to determine the type of 3D printing technology used for the fabrication of orthodontic accessories in 31 studies. Among these, the most utilized technologies were SLA, appearing in 11 instances, and DLP, used in 9 instances. Regarding materials, where specified, the majority of orthodontic accessory devices were fabricated using resin-based materials, accounting for 27 occurrences, followed by metal-based materials, used in 12 cases. This highlights the prevalence of resin and metal as primary materials for 3D-printed orthodontic applications.  
Throughout the 75 articles, the most commonly described advantages of using a digital workflow in manufacturing orthodontic accessories were precision and accuracy, highlighted in 45 articles (60%). These workflows also contributed to improvements in patient safety and predictability and better clinical outcomes, as noted in 37 articles (49%). Additional advantages included improved patient comfort and reduced chair time, mentioned in 17 articles (23%), along with increased efficiency and reduced manual labor in 16 articles (21%). Regarding disadvantages where explicitly stated, the most frequently described were financial issues, including high initial costs of the digital workflow equipment and/or high material costs, reported in 46 articles (61%). The steep learning curve for dental staff and specialized training requirements was another significant issue, mentioned 34 times (45%), followed by the complexity of the digital workflow and increased manufacturing time, as described in 25 articles (33%). Material limitations were noted in 15 articles (20%), and limited data on the long-term success of these devices were highlighted in 12 articles (16%).  
Figure 3: Prisma scheme for the identification of studies.