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The adaptive nature of the bone-periodontal ligament-cementum complex in a ligature-induced periodontitis rat model.

Lee JH, Lin JD, Fong JI, Ryder MI, Ho SP - Biomed Res Int (2013)

Bottom Line: TRAP(+) cells on both sides of the complex significantly increased at 8 days.A gradual change in fibronectin expression from the distal PDL-secondary cementum interfaces through precementum layers was observed when compared to increased and abrupt changes at the mesial PDL-cementum and PDL-bone interfaces in ligated and control groups.Based on our results, we hypothesize that compromised strain fields can be created in a diseased periodontium, which in response to prolonged function can significantly alter the original bone and apical cementum formations.

View Article: PubMed Central - PubMed

Affiliation: Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, CA 94143, USA.

ABSTRACT
The novel aspect of this study involves illustrating significant adaptation of a functionally loaded bone-PDL-cementum complex in a ligature-induced periodontitis rat model. Following 4, 8, and 15 days of ligation, proinflammatory cytokines (TNF- α and RANKL), a mineral resorption indicator (TRAP), and a cell migration and adhesion molecule for tissue regeneration (fibronectin) within the complex were localized and correlated with changes in PDL-space (functional space). At 4 days of ligation, the functional space of the distal complex was widened compared to controls and was positively correlated with an increased expression of TNF- α. At 8 and 15 days, the number of RANKL(+) cells decreased near the mesial alveolar bone crest (ABC) but increased at the distal ABC. TRAP(+) cells on both sides of the complex significantly increased at 8 days. A gradual change in fibronectin expression from the distal PDL-secondary cementum interfaces through precementum layers was observed when compared to increased and abrupt changes at the mesial PDL-cementum and PDL-bone interfaces in ligated and control groups. Based on our results, we hypothesize that compromised strain fields can be created in a diseased periodontium, which in response to prolonged function can significantly alter the original bone and apical cementum formations.

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Morphometric comparisons of control and ligated bone-PDL-cementum complexes, including changes in collagen birefringence. (a) Comparisons of measurements in mesial and distal regions of the CEJ-ABC (i), the interradicular region (ii), and the PDL-space (iii, iv) between control and ligated complexes at 4, 8, and 15 days. Individual graphs were used to compare PDL-space measurements between coronal and apical anatomical locations within mesial (iii) and distal (iv) complexes. (b) The differences between average ligated and average control PDL-space measurements are plotted for each aforementioned anatomical location across time. (c) Histological sections show the distal complex stained with PSR and visualized under polarized light microscopy. Alveolar bone (AB), periodontal ligament (PDL), secondary cementum (SC), and transseptal fibers (TF). Symbols within plots indicate statistically significant differences at 95% confidence interval. &,†,Ψ,¥Significant difference between control and ligated groups. η,‡,κSignificant difference over time. #,+Significant difference between control and ligated groups. *Significant difference over time. A,Β,C,D,E,F,G,HSignificant difference between control and ligated groups. ▲,∆Significant difference over time.
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fig5: Morphometric comparisons of control and ligated bone-PDL-cementum complexes, including changes in collagen birefringence. (a) Comparisons of measurements in mesial and distal regions of the CEJ-ABC (i), the interradicular region (ii), and the PDL-space (iii, iv) between control and ligated complexes at 4, 8, and 15 days. Individual graphs were used to compare PDL-space measurements between coronal and apical anatomical locations within mesial (iii) and distal (iv) complexes. (b) The differences between average ligated and average control PDL-space measurements are plotted for each aforementioned anatomical location across time. (c) Histological sections show the distal complex stained with PSR and visualized under polarized light microscopy. Alveolar bone (AB), periodontal ligament (PDL), secondary cementum (SC), and transseptal fibers (TF). Symbols within plots indicate statistically significant differences at 95% confidence interval. &,†,Ψ,¥Significant difference between control and ligated groups. η,‡,κSignificant difference over time. #,+Significant difference between control and ligated groups. *Significant difference over time. A,Β,C,D,E,F,G,HSignificant difference between control and ligated groups. ▲,∆Significant difference over time.

Mentions: Morphological changes were also evaluated in mesiodistal stained sections, and increased alveolar bone resorption with time was observed (Figure 3(a)). Consistent with μ-XCT morphometric analysis, the CEJ-ABC distance was higher in ligated groups (Figures 3(a) and 5(a)(i)). Multinucleated TRAP(+) cells were observed in endosteal and bone marrow spaces, irrespective of experimental conditions or time points (Figure 3(b)(i–ix)). Active osteoclasts at the PDL-bone interface were also found on the alveolar crest in the 8-day ligated group (Figure 3(b)(ii)). Quantification of TRAP(+) cells showed preferential distal localization regardless of experimental condition or time point (Figures 3(b)(x) and 3(b)(xi)).


The adaptive nature of the bone-periodontal ligament-cementum complex in a ligature-induced periodontitis rat model.

Lee JH, Lin JD, Fong JI, Ryder MI, Ho SP - Biomed Res Int (2013)

Morphometric comparisons of control and ligated bone-PDL-cementum complexes, including changes in collagen birefringence. (a) Comparisons of measurements in mesial and distal regions of the CEJ-ABC (i), the interradicular region (ii), and the PDL-space (iii, iv) between control and ligated complexes at 4, 8, and 15 days. Individual graphs were used to compare PDL-space measurements between coronal and apical anatomical locations within mesial (iii) and distal (iv) complexes. (b) The differences between average ligated and average control PDL-space measurements are plotted for each aforementioned anatomical location across time. (c) Histological sections show the distal complex stained with PSR and visualized under polarized light microscopy. Alveolar bone (AB), periodontal ligament (PDL), secondary cementum (SC), and transseptal fibers (TF). Symbols within plots indicate statistically significant differences at 95% confidence interval. &,†,Ψ,¥Significant difference between control and ligated groups. η,‡,κSignificant difference over time. #,+Significant difference between control and ligated groups. *Significant difference over time. A,Β,C,D,E,F,G,HSignificant difference between control and ligated groups. ▲,∆Significant difference over time.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3713652&req=5

fig5: Morphometric comparisons of control and ligated bone-PDL-cementum complexes, including changes in collagen birefringence. (a) Comparisons of measurements in mesial and distal regions of the CEJ-ABC (i), the interradicular region (ii), and the PDL-space (iii, iv) between control and ligated complexes at 4, 8, and 15 days. Individual graphs were used to compare PDL-space measurements between coronal and apical anatomical locations within mesial (iii) and distal (iv) complexes. (b) The differences between average ligated and average control PDL-space measurements are plotted for each aforementioned anatomical location across time. (c) Histological sections show the distal complex stained with PSR and visualized under polarized light microscopy. Alveolar bone (AB), periodontal ligament (PDL), secondary cementum (SC), and transseptal fibers (TF). Symbols within plots indicate statistically significant differences at 95% confidence interval. &,†,Ψ,¥Significant difference between control and ligated groups. η,‡,κSignificant difference over time. #,+Significant difference between control and ligated groups. *Significant difference over time. A,Β,C,D,E,F,G,HSignificant difference between control and ligated groups. ▲,∆Significant difference over time.
Mentions: Morphological changes were also evaluated in mesiodistal stained sections, and increased alveolar bone resorption with time was observed (Figure 3(a)). Consistent with μ-XCT morphometric analysis, the CEJ-ABC distance was higher in ligated groups (Figures 3(a) and 5(a)(i)). Multinucleated TRAP(+) cells were observed in endosteal and bone marrow spaces, irrespective of experimental conditions or time points (Figure 3(b)(i–ix)). Active osteoclasts at the PDL-bone interface were also found on the alveolar crest in the 8-day ligated group (Figure 3(b)(ii)). Quantification of TRAP(+) cells showed preferential distal localization regardless of experimental condition or time point (Figures 3(b)(x) and 3(b)(xi)).

Bottom Line: TRAP(+) cells on both sides of the complex significantly increased at 8 days.A gradual change in fibronectin expression from the distal PDL-secondary cementum interfaces through precementum layers was observed when compared to increased and abrupt changes at the mesial PDL-cementum and PDL-bone interfaces in ligated and control groups.Based on our results, we hypothesize that compromised strain fields can be created in a diseased periodontium, which in response to prolonged function can significantly alter the original bone and apical cementum formations.

View Article: PubMed Central - PubMed

Affiliation: Division of Biomaterials and Bioengineering, Department of Preventive and Restorative Dental Sciences, University of California, San Francisco, CA 94143, USA.

ABSTRACT
The novel aspect of this study involves illustrating significant adaptation of a functionally loaded bone-PDL-cementum complex in a ligature-induced periodontitis rat model. Following 4, 8, and 15 days of ligation, proinflammatory cytokines (TNF- α and RANKL), a mineral resorption indicator (TRAP), and a cell migration and adhesion molecule for tissue regeneration (fibronectin) within the complex were localized and correlated with changes in PDL-space (functional space). At 4 days of ligation, the functional space of the distal complex was widened compared to controls and was positively correlated with an increased expression of TNF- α. At 8 and 15 days, the number of RANKL(+) cells decreased near the mesial alveolar bone crest (ABC) but increased at the distal ABC. TRAP(+) cells on both sides of the complex significantly increased at 8 days. A gradual change in fibronectin expression from the distal PDL-secondary cementum interfaces through precementum layers was observed when compared to increased and abrupt changes at the mesial PDL-cementum and PDL-bone interfaces in ligated and control groups. Based on our results, we hypothesize that compromised strain fields can be created in a diseased periodontium, which in response to prolonged function can significantly alter the original bone and apical cementum formations.

Show MeSH
Related in: MedlinePlus