The intricate anatomy of the periodontal ligament and its development: Lessons for periodontal regeneration

Abstract

The periodontal ligament (PDL) connects the tooth root and alveolar bone. It is an aligned fibrous network that is interposed between, and anchored to, both mineralized surfaces. Periodontal disease is common and reduces the ability of the PDL to act as a shock absorber, a barrier for pathogens and a sensor of mastication. Although disease progression can be stopped, current therapies do not primarily focus on tissue regeneration. Functional regeneration of PDL may be achieved using innovative techniques, such as tissue engineering. However, the complex fibrillar architecture of the PDL, essential to withstand high forces, makes PDL tissue engineering very challenging. This challenge may be met by studying PDL anatomy and development. Understanding PDL anatomy, development and maintenance provides clues regarding the specific events that need to be mimicked for the formation of this intricate tissue. Owing to the specific composition of the PDL, which develops by self-organization, a different approach than the typical combination of biomaterials, growth factors and regenerative cells is necessary for functional PDL engineering. Most specifically, the architecture of the new PDL to be formed does not need to be dictated by textured biomaterials but can emerge from the local mechanical loading conditions. Elastic hydrogels are optimal to fill the space properly between tooth and bone, may house cells and growth factors to enhance regeneration and allow self-optimization by the alignment to local stresses. We suggest that cells and materials should be placed in a proper mechanical environment to initiate a process of self-organization resulting in a functional architecture of the PDL.

Developing an All‐Digital Workflow for Dental Skills Assessment: Part II, Surface Analysis, Benchmarking, and Grading

“…Selection of a reference standard tooth is an arbitrary institutional decision, and for purposes of this study, we selected the typodont tooth as having representative morphologic contours, adequately representing those that would function harmoniously in the virtual patient "mouth." [7][8][9][10][11][12][15][16][17][18][19][20][21][22] Using individual aspect clinical data to reine the tolerance to ±0.38 mm allows a single value to be applied to the entire surface, which simpliies the digital grading worklow. Initially, we uniformly applied a ±0.50 mm surface contour tolerance comparable to that reported by McPherson et al to each aspect of the tooth.…”

“…[7][8][9][10][11][12] Each of the deined surface contours of the reference tooth (mesial proximal, distal proximal, facial axial, lingual axial, and occlusal) was digitally segmented, and the total surface area in each segment was computed using Autodesk Meshmixer (www.meshmixer.com; Figure 1). This tolerance was subsequently reined to ±0.38 mm following a survey of peer-reviewed literature to determine clinically acceptable thresholds that, if exceeded, would lead to biological or biomechanical morbidities.…”

Changes in characteristics of periodontal ligament stem cells in spheroid culture

“…The periodontal ligament (PDL) is a thin layer of connective tissue located between the alveolar bone and tooth that absorbs mastication forces by bridging the two hard tissues . In addition, it functions as a shock absorber; it is known that PDL has important roles in homeostasis, wound healing, and the regeneration of periodontal tissues by supplying stem/progenitor cells to surrounding tissues .…”

Analysis of mineral apposition rates during alveolar bone regeneration over three weeks following transfer of BMP-2/7 gene via in vivo electroporation

“…4-6 However, as all these therapies are accompanied by surgical procedures, patients face the risk of complications, such as post-operative infection or fractures. 7-9 Therefore, effective nonsurgical therapy for alveolar bone regeneration offers an appealing clinical alternative to such patients.…”