title: Stress and displacement pattern evaluation using two different palatal expanders in unilateral cleft lip and palate: a three-dimensional finite element analysis.
abstract: BACKGROUND
  In this finite element (FE) study, the stress distribution and displacement pattern was evaluated in the mid-palatal area and around circum-maxillary sutures exerted by bone-borne palatal expander (BBPE) in comparison with conventional HYRAX rapid palatal expander in unilateral cleft lip and palate.
  
  
  METHODS
  Computed tomography scan images of a patient with unilateral cleft palate was used to create a FE model of the maxillary bone along with circum-maxillary sutures. A three-dimensional model of the conventional HYRAX (Hygienic Rapid Expander) expander and custom-made BBPE was created by laser scanning and programmed into the FE model.
  
  
  RESULTS
  With the BBPE, the maximum stress was observed at the implant insertion site, whereas with the conventional HYRAX expander, it was at the dentition level. Among the circum-maxillary sutures, the zygomaticomaxillary suture experienced maximum stress followed by the zygomaticotemporal and nasomaxillary sutures. Displacement in the X-axis (transverse) was highest on the cleft side, and in the Y-axis (antero-posterior), it was highest in the posterior region in the BBPE.
  
  
  CONCLUSIONS
  The total displacement was observed maximum in the mid-palatal cleft area in the BBPE, and it produced true skeletal expansion at the alveolar level without any dental tipping when compared with the conventional HYRAX expander.
authors: Department of Orthodontics, Indira Gandhi Institute of Dental Sciences, SBV University, Puducherry, 605402, India.
authors: Anoop
authors: A
authors: Mathew
authors: Department of Orthodontics and Dentofacial Orthopedics, Meenakshi Ammal Dental College & Hospital, Meenakshi University (MAHER), Alapakkam Main Road, Maduravoyal, Chennai, Tamilnadu, 600095, India. orthoksn@yahoo.co.in.
authors: K S
authors: KS
authors: Nagachandran
authors: Department of Orthodontics and Dentofacial Orthopedics, Meenakshi Ammal Dental College & Hospital, Meenakshi University (MAHER), Alapakkam Main Road, Maduravoyal, Chennai, Tamilnadu, 600095, India.
authors: Devaki
authors: D
authors: Vijayalakshmi
mesh_terms: D000539:Alveolar Process / Q000473:pathology; D001696:Biomechanical Phenomena; D002648:Child; D002971:Cleft Lip / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D002972:Cleft Palate / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D003198:Computer Simulation; D003393:Cranial Sutures / Q000473:pathology / Q000503:physiopathology; D003481:Cuspid; D015921:Dental Implants; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008437:Maxilla / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D008954:Models, Biological; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation; D016382:Orthodontic Appliance Design / Q000295:instrumentation; D010155:Palatal Expansion Technique / Q000145:classification / Q000295:instrumentation*; D010159:Palate / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed / Q000379:methods; D014070:Tooth
chemical_list: D015921:Dental Implants
keywords: Cleft lip and palate; Finite element method; Microimplant; Rapid palatal expansion