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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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In vivo rat ligature model for the induction of acute periodontitis. (a) Photograph illustrates lipopolysaccharide (LPS) soaked 4–0 braided silk threads in the diastemata flanking left/right second maxillary molars. Controls were flossed in the same interproximal regions. (b) Schematic illustrates the targeted regions of the fibrous joint within the study. (c) 3D tomogram illustrates the lingual-sagittal, mid-sagittal, and buccal-sagittal 2D virtual sections through a second maxillary molar used for morphometrics. Anatomical landmarks used to measure alveolar bone crest recession (CEJ-ABC) are indicated. (d) 2D virtual section illustrates anatomical landmarks to measure interradicular distance and PDL width. Division of the bone-PDL-cementum complex into coronal, middle, and apical sections for PDL-space measurements is also illustrated.
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fig1: In vivo rat ligature model for the induction of acute periodontitis. (a) Photograph illustrates lipopolysaccharide (LPS) soaked 4–0 braided silk threads in the diastemata flanking left/right second maxillary molars. Controls were flossed in the same interproximal regions. (b) Schematic illustrates the targeted regions of the fibrous joint within the study. (c) 3D tomogram illustrates the lingual-sagittal, mid-sagittal, and buccal-sagittal 2D virtual sections through a second maxillary molar used for morphometrics. Anatomical landmarks used to measure alveolar bone crest recession (CEJ-ABC) are indicated. (d) 2D virtual section illustrates anatomical landmarks to measure interradicular distance and PDL width. Division of the bone-PDL-cementum complex into coronal, middle, and apical sections for PDL-space measurements is also illustrated.

Mentions: 4–0 silk suture threads soaked in 1 mg of lipopolysaccharide (LPS) from Escherichia coli serotype 055:B5 (Sigma-Aldrich, USA) per 1 mL of 1x Tris buffer were used to induce periodontitis (N = 5 per time point). Threads were placed between the first and second molars and the second and third molars of both maxillae (Figure 1(a)). Molars were religated every 2-3 days to ensure retention. Control rats (N = 5 per time point) were flossed every 2-3 days with 4–0 silk ligatures without LPS. Rats were euthanized after 4, 8, and 15 days of ligation. Maxillae were harvested and hemisected. Right hemimaxillae were stored in 70% ethanol for micro-XCT analysis. Left hemimaxillae were fixed in 4% paraformaldehyde (PFA) at room temperature overnight for histology.


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)

In vivo rat ligature model for the induction of acute periodontitis. (a) Photograph illustrates lipopolysaccharide (LPS) soaked 4–0 braided silk threads in the diastemata flanking left/right second maxillary molars. Controls were flossed in the same interproximal regions. (b) Schematic illustrates the targeted regions of the fibrous joint within the study. (c) 3D tomogram illustrates the lingual-sagittal, mid-sagittal, and buccal-sagittal 2D virtual sections through a second maxillary molar used for morphometrics. Anatomical landmarks used to measure alveolar bone crest recession (CEJ-ABC) are indicated. (d) 2D virtual section illustrates anatomical landmarks to measure interradicular distance and PDL width. Division of the bone-PDL-cementum complex into coronal, middle, and apical sections for PDL-space measurements is also illustrated.
© Copyright Policy
Related In: Results  -  Collection

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

fig1: In vivo rat ligature model for the induction of acute periodontitis. (a) Photograph illustrates lipopolysaccharide (LPS) soaked 4–0 braided silk threads in the diastemata flanking left/right second maxillary molars. Controls were flossed in the same interproximal regions. (b) Schematic illustrates the targeted regions of the fibrous joint within the study. (c) 3D tomogram illustrates the lingual-sagittal, mid-sagittal, and buccal-sagittal 2D virtual sections through a second maxillary molar used for morphometrics. Anatomical landmarks used to measure alveolar bone crest recession (CEJ-ABC) are indicated. (d) 2D virtual section illustrates anatomical landmarks to measure interradicular distance and PDL width. Division of the bone-PDL-cementum complex into coronal, middle, and apical sections for PDL-space measurements is also illustrated.
Mentions: 4–0 silk suture threads soaked in 1 mg of lipopolysaccharide (LPS) from Escherichia coli serotype 055:B5 (Sigma-Aldrich, USA) per 1 mL of 1x Tris buffer were used to induce periodontitis (N = 5 per time point). Threads were placed between the first and second molars and the second and third molars of both maxillae (Figure 1(a)). Molars were religated every 2-3 days to ensure retention. Control rats (N = 5 per time point) were flossed every 2-3 days with 4–0 silk ligatures without LPS. Rats were euthanized after 4, 8, and 15 days of ligation. Maxillae were harvested and hemisected. Right hemimaxillae were stored in 70% ethanol for micro-XCT analysis. Left hemimaxillae were fixed in 4% paraformaldehyde (PFA) at room temperature overnight for histology.

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