PhD Scientific Days 2022

Clinical Medicine I. (Poster discussion will take place in the Aula during the Coffee Break)

Evaluation of the Buccal Rolling Effect of Different Types of Maxillary Expanders

Text of the abstract

Introduction:Correction of transverse maxillary deficiency by dentally anchored expanders has been part of the orthodontic practice for centuries. In recent decades, the dentally anchored expanders are more and more replaced by expanders anchored both dentally and skeletally and purely skeletally anchored expanders. The rationale behind is to decrease dental and increase skeletal expansion.
Aims: To investigate the dental effects of hybrid and bone-borne maxillary expanders.
Methods: 38 patients treated with maxillary expansion were included into this retrospective study: 10 patients treated with hybrid hyrax, 5 with MICRO2 and 14 with MICRO4 expanders (purely bone-borne expanders). For the control group 7 patients who were treated with a tooth-borne expander and surgically assisted rapid maxillary expansion (SARME) were used.
Alginate impressions taken before and after expansion were collected and digitalized with PlanScan Lab scanner (©PLANMECA OY, Planmeca Group). Digital models were transferred into MeshLab software, followed by manual identification of cusp coordinates of first premolars and molars considered as marker teeth to evaluate their transversal width and tilting before and after expansion.
Result: The Hybrid Hyrax group showed buccal rolling of +1.66(SD 10,47)°and -6.06(SD 5,93)° between premolars and molars respectively, while exhibiting an expansion of 5.07(SD 2,56) mm and 6.27(SD 3,56)mm. For the MICRO2 group the findings were 3.04(SD 3,47)° and -2.82(SD 3,84)° for buccal rolling and expansion of 4.54(SD 2,1)mm and 8,14(SD 6,35)mm respectively. The MICRO4 scored an average buccal rolling of 4.52(SD 9,98)° and -1,68(SD 7,12)° and an expansion of 5,99(SD 2,69)mm and 4,7(SD 2,5)mm. Control group patients who underwent SARME had an average buccal rolling of + 2.93(SD 8,26)° and -0,91(SD 6,24)° while expansion was 8.71(SD 3,51)mm between premolars and 10.46(SD1,97)mm between molars.
Conclusion: Premolars tended to tip outward and molars to tilt inward with all types of expanders. Expansion in the bone-borne groups (MICRO2 and MICRO4) was more prominent in the premolar area than the molar region, while in the tooth borne group (SARME and hybrid hyrax) there was more dental expansion in the molar area.
Funding : Semmelweis University Department of Dentistry internal research funding(Kari kutatási pályázat – 18806-/FOFTO/2022)