title: Changes of anterior maxillary alveolar bone thickness following incisor proclination and extrusion.
abstract: OBJECTIVE
  To investigate changes in maxillary alveolar bone thickness after maxillary incisor proclination and extrusion during anterior crossbite correction in a group of growing patients with Class III malocclusion.
  
  
  METHODS
  Maxillary incisors of 15 growing patients with anterior crossbite were proclined and extruded with 0.016″ beta-titanium advancing loops and Class III elastics. Lateral cephalograms were recorded before advancement (T0) and 4 months after a normal overjet and overbite were achieved (T1). Changes in alveolar bone thickness surrounding the maxillary incisors at the crestal (S1), midroot (S2), and apical (S3) levels were measured using cone-beam computed tomography (CBCT). Paired t-tests were used to determine the significance of the changes. A Spearman rank correlation analysis was performed to explore the relationship between thickness changes and the rate and amount of incisor movements.
  
  
  RESULTS
  Although statistically significant decreases were observed in palatal and total bone thickness at the S2 and S3 level (P < .05), the amounts of these changes were clinically insignificant, ranging from 0.34 to 0.59 mm. Changes in labial bone thickness at all levels were not significant. Changes in palatal bone thickness at S3 were negatively correlated with changes in incisor inclination. (r  =  -0.71; P < .05).
  
  
  CONCLUSIONS
  In a group of growing patients with Class III malocclusion undergoing anterior crossbite correction, controlled tipping mechanics accompanied by extrusive force may produce successful tooth movement with minimal iatrogenic detriment to the alveolar bone.
authors.affiliation: a  Assistant Professor, Orthodontic Section, Department of Preventive Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Udom
authors.initials: U
authors.lastname: Thongudomporn
authors.affiliation: b  Associate Professor, Orthodontic Section, Department of Preventive Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Chairat
authors.initials: C
authors.lastname: Charoemratrote
authors.affiliation: c  Orthodontist, Chaibadan Hospital, Chaibadan, Lopburi, Thailand.
authors.forename: Sarayut
authors.initials: S
authors.lastname: Jearapongpakorn
mesh_terms: D000497:Alloys / Q000737:chemistry; D000539:Alveolar Process / Q000473:pathology*; D002508:Cephalometry / Q000379:methods; D002648:Child; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003722:Dental Alloys / Q000737:chemistry; D020724:Elastomers / Q000737:chemistry; D005260:Female; D006801:Humans; D007180:Incisor / Q000473:pathology*; D008297:Male; D008313:Malocclusion, Angle Class III / Q000628:therapy; D008437:Maxilla / Q000473:pathology*; D050793:Orthodontic Extrusion / Q000295:instrumentation / Q000379:methods*; D009969:Orthodontic Wires; D010159:Palate / Q000473:pathology; D011446:Prospective Studies; D013193:Stainless Steel / Q000737:chemistry; D014025:Titanium / Q000737:chemistry; D019227:Tooth Apex / Q000473:pathology; D014087:Tooth Movement Techniques / Q000295:instrumentation / Q000379:methods*; D014092:Tooth Root / Q000473:pathology
chemical_list: D000497:Alloys; D003722:Dental Alloys; D020724:Elastomers; C023988:beta titanium; C525450:titanium molybdenum alloy; D013193:Stainless Steel; D014025:Titanium
keywords: Alveolar bone thickness; CBCT; Incisor extrusion; Incisor proclination; Light force