Periodontal Ligament Surface Research Articles

Influence of systemic sclerosis on periodontal health: A case-control study.

Patients with systemic sclerosis (SSc) present various clinical and radiological oral manifestations. However, precise evaluation of the oral features associated with diffuse cutaneous SSc (dcSSc) and limited cutaneous SSc (lcSSc) is limited. The objective of this study was to evaluate the periodontal ligament (PDL) surface in SSc patients in comparison with controls. Assessment of oral-health-related quality of life (OHRQoL) and the levels of different biomarkers in the gingival crevicular fluid (GCF) was performed. SSc patients and matched controls underwent standardized oral examination and cone-beam computed tomography (CBCT). Levels of interleukin-6 (IL-6), chemokine (C-X-C motif) ligand 4 (CXCL-4) and matrix metalloproteinase-9 (MMP-9) in the GCF were determined by enzyme-linked immunosorbent assay. PDL surface was measured on CBCT axial views. OHRQoL was quantified using the Mouth Handicap in SSc Scale (MHISS). Thirty-nine SSc patients and 39 controls were included. SSc patients exhibited increased PDL surface, higher number of missing teeth as well as elevated IL-6, MMP-9 and CXCL-4 levels. Reduced mouth opening was observed in dcSSc but not in lcSSc patients. MHISS score was higher in dcSSc than in lcSSc patients. Although worse periodontal parameters were found in both subgroups compared with controls, dcSSc patients presented lower gingival inflammation. SSc is associated with PDL space widening, impaired oral health and OHRQoL.

Stress distribution on dentin-cement-post interface varying root canal and glass fiber post diameters. A three-dimensional finite element analysis based on micro-CT data

ObjectiveThe aim of the present study was to analyze the influence of root canal and glass fiber post diameters on the biomechanical behavior of the dentin/cement/post interface of a root-filled tooth using 3D finite element analysis. Material and MethodsSix models were built using micro-CT imaging data and SolidWorks 2007 software, varying the root canal (C) and the glass fiber post (P) diameters: C1P1-C=1 mm and P=1 mm; C2P1-C=2 mm and P=1 mm; C2P2-C=2 mm and P=2 mm; C3P1-C=3 mm and P=1 mm; C3P2-C=3 mm and P=2 mm; and C3P3-C=3 mm and P=3 mm. The numerical analysis was conducted with ANSYS Workbench 10.0. An oblique force (180 N at 45º) was applied to the palatal surface of the central incisor. The periodontal ligament surface was constrained on the three axes (x=y=z=0). Maximum principal stress (σmax) values were evaluated for the root dentin, cement layer, and glass fiber post. Results:The most evident stress was observed in the glass fiber post at C3P1 (323 MPa), and the maximum stress in the cement layer occurred at C1P1 (43.2 MPa). The stress on the root dentin was almost constant in all models with a peak in tension at C2P1 (64.5 MPa). ConclusionThe greatest discrepancy between root canal and post diameters is favorable for stress concentration at the post surface. The dentin remaining after the various root canal preparations did not increase the stress levels on the root.

Modeling of Trabecular Bone and Lamina Dura Following Selective Alveolar Decortication in Rats

Modifying the balance between resorption and apposition through selectively injuring the cortical plate of the alveolus has been an approach to speed tooth movement and is referred to as periodontally accelerated osteogenic orthodontics. The aim of this study was to investigate the alveolar response to corticotomy as a function of time and proximity to the surgical injury in a rat model. Maxillary buccal and lingual cortical plates were injured in 36 healthy adult rats adjacent to the upper left first molars. Twenty-four animals were euthanized at 3, 7, or 11 weeks. In one group, the maxillae were removed and stripped of soft tissues, and histomorphometric analysis was performed to study alveolar spongiosa and periodontal ligament (PDL) modeling dynamics. Catabolic activity was analyzed with tartrate-resistant acid phosphatase-positive osteoclasts and preosteoclasts. Anabolic actions were measured using a fluorescent vital bone stain series followed by sacrifice at 30 and 51 days. To further analyze the new bone formation, a separate group of animals were fed with calcein fluorescent stain and processed for non-decalcified fluorescent stain histology. At 3 weeks, the surgery group had significantly (P <0.05) less calcified spongiosa bone surface, greater periodontal ligament surface, higher osteoclast number, and greater lamina dura apposition width. The catabolic activity (osteoclast count) and anabolic activity (apposition rate) were three-fold greater, calcified spongiosa decreased by two-fold, and PDL surface increased by two-fold. Surgical injury to the alveolus that induced a significant increase in tissue turnover by week 3 dissipated to a steady state by postoperative week 11. The impact of the injury was localized to the area immediately adjacent to the decortication injury. Selective alveolar decortication induced increased turnover of alveolar spongiosa, and the activity was localized; dramatic escalation of demineralization-remineralization dynamics is the likely biologic mechanism underlying rapid tooth movement following selective alveolar decortication.