The Effect of Gingival Fibroblasts and Ultrasound on Orthodontically Induced Root Resorption in Beagle Dogs

• Author / Creator

  Crossman, Jacqueline J

• A favourable tooth crown-to-root ratio is required for supporting the tooth, but also for withstanding occlusal forces. This ratio is adversely affected when the tooth root is shortened. Orthodontically induced tooth root resorption is an unwanted side effect of orthodontic tooth movement. In severe cases, resorption of the tooth root apex progressing coronally results in tooth root shortening, which may lead to tooth loss. This type of root resorption is reported to occur in 40% of adults receiving orthodontic tooth movement where these patients had root shortening of 2.5 mm or more in at least one of their teeth. Orthodontically induced root resorption may even occur within 35 days of orthodontic treatment and even with only light forces. Currently, no simple and reliable technique is available to repair the damage caused by orthodontically induced root resorption, therefore, a new method is needed that can regenerate the lost tooth root tissue. Low intensity pulsed ultrasound has been reported to enhance osteoblastic differentiation, increase proliferation, and induce osteogenic differentiation in cells. It has also been shown to enhance the repair of resorbed tooth roots in Beagle dogs. Another treatment technique involved in periodontal repair (including alveolar bone and cementum) is stem cell therapy. Stem cells, and cells that have stem cell properties, that possibly could be used in periodontal repair, including periodontal ligament (PDL) stem cells, bone marrow stem cells, and gingival cells/fibroblasts, have shown promise in repairing periodontal defects, however, gingival cells/fibroblasts are more easily accessible and involve less donor site morbidity. Previous to the current study, there is no study that had evaluated the effect of LIPUS and osteogenic induced gingival fibroblasts (OIGFs) on the repair of orthodontically induced root resorption. Therefore, the aim of the present study was to evaluate the effect of these treatment modalities (OIGFs and LIPUS) using histomorphometric and micro-computed tomography analyses. The results of this study using histomorphometric analysis revealed that ultrasound and the combination of ultrasound and OIGFs were effective at increasing cementum thickness near the apex of the root (p 0.05). Using micro-computed tomographic analysis, it was shown that ultrasound, OIGFs , and the combination of the two treatments had an effect on reducing root resorption lacunae depth and volume (p 0.05). In conclusion, using low intensity pulsed ultrasound and OIGFs, alone or in combination with each other, may have a promising effect on repairing damage caused by orthodontically induced root resorption. Additional studies that examine these treatments’ effects on the inflammatory aspect of root resorption, employing a carefully separated multipotent gingival cells, and track/ label these cells to determine their incorporation into the tissues are required to fully understand their effect in this repair process.

• Subjects / Keywords

  • Root resorption lacunae
  • Micro-computed tomography
  • Cementum
  • Low intensity pulsed ultrasound
  • Periodontal ligament
  • Orthodontically induced root resorption
  • Gingival fibroblasts

• Graduation date

  Spring 2015

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3891200N

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.