title: Quantitative effects of a nickel-titanium palatal expander on skeletal and dental structures in the primary and mixed dentition: a preliminary study.
abstract: The present study analysed the six-month effects of a nickel-titanium (NiTi) palatal expander on the dental and palatal structures of four primary (mean age 5.8 years) and nine mixed dentition children (mean age 8.7 years), with a posterior unilateral crossbite. Standardized dental and palatal landmarks were digitized using a three-dimensional (3D) electromagnetic instrument. Collected data were analysed with geometric-mathematical models. During a six-month interval, the natural growth and development of the dental arches and hard tissue palate was negligible, as assessed in seven control children (two in the primary dentition, mean age 4.4 years; five in the mixed dentition, mean age 7.7 years). In all children the crossbite was completely corrected. Indeed, dental expansion was always more than or corresponded to the palatal expansion. A smoothing of the size-independent (shape) palatal curvature in the transverse plane was observed. No differences in maximum palatal height were noted. Symmetrical derotation of the anchorage teeth in a distal direction occurred in almost all children. The inclination of the facial axis of the clinical crown (FACC) in the anatomical transverse plane of those teeth with differences between dental and palatal expansion always showed significant modifications (vestibular inclination up to 16.7 degrees). The clinical crown height of anchorage teeth remained nearly the same in all patients. No significant modifications in mandibular arch size were observed. The increase in maxillary arch width, especially in younger children, was probably due to a combination of different effects: opening of the midpalatal suture, tipping of the alveolar process, and molar tipping.
authors.affiliation: Functional Anatomy Research Center, Laboratorio di Anatomia Funzionale dell'Apparato Stomatognatico, Dipartimento di Anatomia Umana, Facoltà di Medicina e Chirurgia, Università degli Studi di Milano, Italy.
authors.forename: Virgilio F
authors.initials: VF
authors.lastname: Ferrario
authors.forename: Giovanna
authors.initials: G
authors.lastname: Garattini
authors.forename: Anna
authors.initials: A
authors.lastname: Colombo
authors.forename: Vittorio
authors.initials: V
authors.lastname: Filippi
authors.forename: Silvio
authors.initials: S
authors.lastname: Pozzoli
authors.forename: Chiarella
authors.initials: C
authors.lastname: Sforza
mesh_terms: D000539:Alveolar Process / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003722:Dental Alloys / Q000737:chemistry; D003724:Dental Arch / Q000473:pathology; D003818:Dentition, Mixed; D005147:Facial Bones / Q000254:growth & development / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008310:Malocclusion / Q000628:therapy; D008437:Maxilla / Q000473:pathology; D008963:Molar / Q000473:pathology; D009532:Nickel / Q000737:chemistry; D016382:Orthodontic Appliance Design; D010155:Palatal Expansion Technique / Q000295:instrumentation*; D010159:Palate / Q000473:pathology; D014025:Titanium / Q000737:chemistry; D019228:Tooth Crown / Q000473:pathology; D014094:Tooth, Deciduous / Q000473:pathology*
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium