title: Effect of Intraoral Aging on Debris Accumulation and Friction of First Molar Tubes.
abstract: OBJECTIVE
  The aim of this article was to evaluate the impact of intraoral aging and site specificity on debris accumulation and friction in molar tubes after intraoral use.
  
  
  METHODS
  A total of 80 intraorally used first molar convertible tubes were provided by 20 orthodontic adolescent patients after 6 months of treatment. The specimens were divided into eight groups (n = 10) according to the mouth quadrant and the type of examination [four groups of ten tubes for scanning electron microscope (SEM) and four groups of ten tubes for friction test]. Scanning electron microscope examination was performed after opening the convertible caps and friction test was executed using a 0.019'' × 0.025'' stainless steel wire, which was inserted in the tubes belonging to each group. The Mann-Whitney test, analysis of variance (ANOVA), and Bonferroni tests were performed for statistical analysis at 0.01 level of significance.
  
  
  RESULTS
  There was a significant increase in the amount of debris and frictional force after 6 months of intraoral exposure (p < 0.0001). Debris scores were higher (10% increase) on the upper tubes when compared with the lower ones, with no statistical difference. Mean frictional force ranged from 0.22 to 0.26 N according to the mouth quadrant, but the difference between groups was also not significant.
  
  
  CONCLUSIONS
  After 6 months of intraoral exposure, there was a significant increase in the amount of debris in the first molar tube slots, leading to significantly higher frictional forces during sliding mechanics. The influence of site specificity on the amount of debris and on frictional forces of the first molar tubes could not be demonstrated.
  
  
  CONCLUSIONS
  Molar tubes should be cleaned, before and during sliding mechanics, in order to minimize friction.
authors.affiliation: Department of Orthodontics, Faculty of Dental Medicine Saint-Joseph University of Beirut, Beirut, Lebanon.
authors.forename: Edmond
authors.initials: E
authors.lastname: Chaptini
authors.affiliation: Department of Orthodontics, Faculty of Dental Medicine Saint-Joseph University of Beirut, Beirut, Lebanon, e-mail: elie.khoury@usj.edu.lb.
authors.forename: Elie
authors.initials: E
authors.lastname: Khoury
authors.affiliation: Private Practice of Lingual Orthodontics, Milano, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Cacciafesta
authors.affiliation: Faculty of Dental Medicine, Saint-Joseph University of Beirut, Beirut Lebanon.
authors.forename: Nada
authors.initials: N
authors.lastname: Naaman
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002648:Child; D003722:Dental Alloys / Q000737:chemistry; D005260:Female; D017276:Friction; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008963:Molar; D016382:Orthodontic Appliance Design / Q000295:instrumentation*; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013997:Time Factors; D014087:Tooth Movement Techniques; D055815:Young Adult
chemical_list: D003722:Dental Alloys; D013193:Stainless Steel
keywords: Debris; Friction; Intraoral aging Molar tubes.