Original Research
Keywords: MARPE; finite element analysis; mono-cortical anchorage; bi-cortical anchorage; mini-implant stability; transverse maxillary deficiency.
Year : 2026 | Volume : 17 | Issue : 3 | Page : 41-52
FEM-Based Comparison of Peri-implant Stress and Stability in Bi-cortical Versus Mono-cortical Mini-implant Anchorage during Bone-borne Maxillary Expansion
Vikashini Dhakshinamoorthy-1, Pavithranand Ammayappan-2, Praveen Kumar-3, Shaick Ashiq-3
1-Postgraduate Resident, 2-Professor and Head, 3-Assistant Professor, Department of Orthodontics and Dentofacial Orthopedics, Sri Balaji Vidyapeeth University, Puducherry, India.
Address for Correspondence:
Dr Pavithranand Ammayappan MDS FDSRCS (England)
Professor and Head,
Department of Orthodontics and Dentofacial Orthopedics,
Sri Balaji Vidyapeeth University, Puducherry, India.
Mobile: +91 9443183590
email: docanandpavi@gmail.com
ABSTRACT
AIM: The aim of this study was to compare the mechanical stability of mono-cortical and bi-cortical mini-implant anchorage in mini-implant assisted rapid palatal expansion (MARPE) in terms of stress and displacement.
METHODS: Using CBCT data of a healthy adolescent, a 3D finite element model of the maxilla, teeth, periodontal ligament and mid-palatal suture was created. Two different MARPE models were simulated: Model A (4 bi-cortical mini-implants) and Model B (anterior mono-cortical and posterior bi-cortical mini-implants). After performing grid-independence testing, all structures were discretized using tetrahedral and hexahedral elements and were assumed to be isotropic, homogeneous and linearly elastic. The 800 g bilateral orthopaedic forces were applied to each mini-implant in identical boundary conditions. To evaluate mechanical stability, von Mises stress and displacement were analyzed around the mini-implants and in the surrounding cortical bone.
RESULTS: Model A had more uniform stress around all the mini-implants, and minimum von Mises stresses in the cervical areas with minimal displacement. Model B exhibited significant stress concentration in the middle and cervical thirds of the anterior mono-cortical mini-implants, and larger mini-implant displacement than bi-cortical mini-implants, suggesting that it has lower mechanical stability compared to bi-cortical mini-implants.
CONCLUSION: This study, because of the limited FEA applied, showed that full bi-cortical mini-implant anchorage in MARPE resulted in lower peri-implant stress and showed less mini-implant displacement than partial mono-cortical anchorage, indicating greater mechanical stability and a reduced risk of mini-implant instability under orthopaedic loading.
KEYWORDS: MARPE; finite element analysis; mono-cortical anchorage; bi-cortical anchorage; mini-implant stability; transverse maxillary deficiency.
CONFLICT OF INTEREST
Nil
FUNDING
Nil
How to cite this article: Vikashini Dhakshinamoorthy, Pavithranand Ammayappan, Praveen Kumar, Shaick Ashiq. FEM-Based Comparison of Peri-implant Stress and Stability in Bi-cortical Versus Mono-cortical Mini-implant Anchorage during Bone-borne Maxillary Expansion.
Int J OrthodRehabil 2026; 17 (3): 41-52.
Doi: 10.56501/Intjorthodrehabil.172.ijor0103