title: Microdamage of the cortical bone during mini-implant insertion with self-drilling and self-tapping techniques: a randomized controlled trial.
abstract: BACKGROUND
  The purpose of this research was to evaluate microdamage accumulation after mini-implant placement by self-drilling (without a pilot hole) and self-tapping (screwed into a pilot hole) insertion techniques. The null hypothesis was that the mini-implant insertion technique would have no influence on microcrack accumulation and propagation in the cortical bones of the maxillae and mandibles of adult hounds.
  
  
  METHODS
  Mini-implants (n = 162; diameter, 1.6 mm; length, 6 mm) were placed in the maxillae and mandibles of 9 hounds (12-14 months old) with self-drilling and self-tapping insertion techniques. The techniques were randomly assigned to the left or the right side of each jaw. Each hound received 18 mini-implants (10 in the mandible, 8 in the maxilla). Histomorphometric parameters including total crack length and crack surface density were measured. The null hypothesis was rejected in favor of an alternate hypothesis: that the self-drilling technique results in more microdamage (microcracks) accumulation in the adjacent cortical bone in both the maxilla and the mandible immediately after mini-implant placement. A cluster level analysis was used to analyze the data on the outcome measured. Since the measurements were clustered within dogs, a paired-samples t test was used to analyze the average differences between insertion methods at both jaw locations. A significance level of 0.05 was used for both analyses.
  
  
  RESULTS
  The self-drilling technique resulted in greater total crack lengths in both the maxilla and the mandible (maxilla: mean difference, 18.70 ± 7.04 μm/mm(2); CI, 13.29-24.11; mandible: mean difference, 22.98 ± 6.43 μm/mm(2); CI, 18.04-27.93; P <0.05), higher crack surface density in both the maxilla and the mandible (maxilla: mean difference, 10.39 ± 9.16 μm/mm(2); CI, 3.34-17.43; mandible: mean difference, 11.28 ± 3.41 μm/mm(2); CI, 8.65-13.90; P <0.05).
  
  
  CONCLUSIONS
  This study demonstrated greater microdamage in the cortical bones of adult hounds in both the maxilla and the mandible by the self-drilling insertion technique compared with the self-tapping technique.
authors.affiliation: Division of Orthodontics, Health Center, University of Connecticut, Farmington, USA. yadav_sumit17@yahoo.com
authors.forename: Sumit
authors.initials: S
authors.lastname: Yadav
authors.forename: Madhur
authors.initials: M
authors.lastname: Upadhyay
authors.forename: Sean
authors.initials: S
authors.lastname: Liu
authors.forename: Eugene
authors.initials: E
authors.lastname: Roberts
authors.forename: William P
authors.initials: WP
authors.lastname: Neace
authors.forename: Ravindra
authors.initials: R
authors.lastname: Nanda
mesh_terms: D000818:Animals; D003758:Dental Implantation, Endosseous / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D015921:Dental Implants / Q000009:adverse effects*; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D004285:Dogs; D008297:Male; D008338:Mandibular Injuries / Q000209:etiology* / Q000473:pathology; D008437:Maxilla / Q000293:injuries* / Q000473:pathology; D008904:Miniaturization; D052280:Orthodontic Anchorage Procedures / Q000009:adverse effects / Q000295:instrumentation; D011897:Random Allocation
chemical_list: D015921:Dental Implants