Korean J Orthod.  2014 Sep;44(5):263-267. 10.4041/kjod.2014.44.5.263.

Micro-computed tomography analysis of changes in the periodontal ligament and alveolar bone proper induced by occlusal hypofunction of rat molars

Affiliations
  • 1Orthodontic Science, Department of Orofacial Development and Function, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. y.shimizu.orts@tmd.ac.jp

Abstract


OBJECTIVE
To three-dimensionally elucidate the effects of occlusal hypofunction on the periodontal ligament and alveolar bone proper of rat molars by micro-computed tomography (micro-CT).
METHODS
Occlusal function in the molar area was restricted by attaching an anterior bite plate on the maxillary incisors and a metal cap on the mandibular incisors of 5-week-old male Wistar rats for 1 week. The periodontal ligament space and alveolar bone proper around roots of the mandibular first molar were assessed by histology and micro-CT.
RESULTS
The periodontal ligament space was narrower and the alveolar bone proper was sparser and less continuous in the hypofunction group than in the control group. Further, both the volume of the periodontal ligament and the volumetric ratio of the alveolar bone proper to the total tissue in the region of interest were significantly lower in the hypofunction group (p < 0.05).
CONCLUSIONS
Occlusal hypofunction induces atrophic changes in the periodontal ligament and alveolar bone proper of rat molars.

Keyword

Three dimensional scanner; Computed tomography; Histology; Bone biology; Occlusal stimuli; Micro-computed tomography

MeSH Terms

Animals
Humans
Incisor
Male
Molar*
Periodontal Ligament*
Rats*
Rats, Wistar

Figure

  • Figure 1 A, The experimental model; B, histological observational area (rectangular area); C, representative hematoxylin and eosin-stained sections (Scale = 250 µm). M, Mesial; D, distal; PL, periodontal ligament; AP, alveolar bone proper; AB, inter-radicular alveolar bone.

  • Figure 2 A, Three-dimensional reconstructed images of the periodontal ligament (PDL) space (Scale = 1 mm); B, comparison of tissue volume (TV) around the mesial root of the mandibular first molar. ***p < 0.001 by the Mann-Whitney U-test. M, Mesial; D, distal.

  • Figure 3 A, Three-dimensional reconstructed images of the periodontal ligament (PDL) space (Scale = 1 mm); B, comparison of tissue volume (TV) around the distal root of the mandibular first molar. ***p < 0.001 by the Mann-Whitney U-test. M, Mesial; D, distal.

  • Figure 4 A, Three-dimensional reconstructed images of the alveolar bone proper (Scale = 1 mm); B, comparison of the bone-to-tissue volume (BV/TV) ratio around the mesial root of the mandibular first molar. *p < 0.05 by the Mann-Whitney U-test. M, Mesial; D, distal.

  • Figure 5 A, Three-dimensional reconstructed images of the alveolar bone proper (Scale = 1 mm); B, comparison of the bone-to-tissue volume (BV/TV) ratio around the distal root of the mandibular first molar. *p < 0.05 by the Mann-Whitney U-test. M, Mesial; D, distal.


Cited by  2 articles

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Soonshin Hwang, Yoon Jeong Choi, Chooryung J. Chung, Kyung-Ho Kim
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