The evaluation of post orthodontic treatment stability during retention with essix type retainers- 3D analysis

Abstract

Retention following orthodontic treatment is required to ensure post treatment teeth stability and minimize relapse. A significant increase in Essix retainers use, in recent years, implies the necessity for further investigation of their effectiveness in preventing post treatment relapse. The aim of this study was to analyze the 3D digital models in order to determine the amount of teeth movement, changes in dental arch dimensions 3, 6 and 12 months after orthodontic treatment and factors influencing the degree of relapse. The rationale, reliability and benefits of 3D scanner use for the registration of teeth movement was investigated. The study included 45 patients who have completed orthodontic treatment with retention performed by using of Essix retainer. Post treatment changes in teeth position were analyzed by superimposition of 3D digital dental models made at the end of treatment, and follow up appointments 3, 6 and 12 months after treatment. Evaluation of changes in dental arch dimensions was achieved by linear measuring. The influence of various factors on the expression of post treatment relapse was also examined. Statistically significant differences in teeth position were found in follow up period, with the most distinct changes in the first three months. Changes in dimensions of arches as well as influence of various factors on retention were not significant. Application of 3D scanner in evaluation of teeth position and dental arch dimensions provides accurate and complete data. Information can be used to assess changes in the position of teeth and the dimensions of the dental arches. After the end of orthodontic treatment, tooth movement was inevitable, while dimension of arches showed stability. However, there are no clear parameters that can help in the prediction of degree of relapse.

Da bi se obezbedila postterapijska stabilnost, po završetku aktivne faze ortodontske terapije neophodno je sprovesti retenciju. Folije predstavljaju sve češće primenjivani vid retencije, stoga postoji potreba da se ispita njihova efikasnost u sprečavanju nastanka postterapijskog recidiva. Cilj ove studije je bio da se analizom 3D digitalnih modela vilica utvrditi da li i u kojoj meri dolazi do pomeranja zuba i promene dimenzija zubnih lukova u periodu od 3, 6 i 12 meseci postterapijski, kao i da se utvrde faktori koji utiču na stepen izraženosti recidiva. Jedan od cijeva je bio i da se ispita validnost i pouzdanost korišćenog 3D skenera i softvera u registrovanju pomeranja zuba. Studijom je obuhvaćeno 45 pacijenata kod kojih je nakon terapije fiksnim ortodontskim aparatima sprovedena retencija folijama. Postterapijske promene položaja zuba analizirane su superponiranjem 3D digitalnih modela vilica u 0., 3., 6. i 12. mesecu postterapijski. Analiza promena dimenzija zubnih lukova sprovedena je linearnim premeravanjem digitalnih modela vilica. Ispitivan je i uticaj različitih faktora na izraženost postterapijskog recidiva. Postterapijski dolazi do statistički značajne promene položaja zuba u svim praćenim vremenskim intervalima, s tim da su najizraženije u prva tri meseca. Promene u 12. mesecu postterapijski su izraženije u gornjoj vilicu. Promene dimenzija zubnih lukova su zanemarljive. Za većinu faktora nije pokazano da imaju značajan uticaj na postterapijsku stabilnost. Primenom 3D laser skenera dobijaju tačni i precizni podaci koji se mogu koristiti za procenu promene položaja zuba i dimenzija zubnih lukova. Po završetku ortodontske terapije, u periodu aktivne retencije folijama, dolazi do pomeranja zuba dok dimenzije zubnih lukova ostaju nepromenjene. Ne postoje jasni parametri na osnovu kojih možemo sa sigurnošću predvideti da li će i u kojoj meri doći do pojave recidiva nakon sprovedene ortodontske terapije.