© Springer International Publishing Switzerland 2016
Michel Goldberg (ed.)Understanding Dental Caries10.1007/978-3-319-30552-3_14
14. Cervical Regeneration
University Paris Descartes, Sorbonne, Paris Cité and INSERM UMR-S1124, 45 rue des Saints Pères, Cedex 06, 75270 Paris, France
In different reports, cervical lesions are named erosion, abrasion, chemical abrasion, and denudation. The leading concept is that occlusal loading could be implicated in cervical stress and consequently may induce a loss of cervical tooth structure. Cervical lesion has gained over all the other terminology. Excessive occlusal biomechanical forces seem to cause loss of superficial root dentin, causing thermo-sensitivity that is mediated by dentinal fluid shifts that activate potassium ion channel receptors in pulpal nerves innervating such dentin. Carious cervical lesions may be restored after etching by adhesives combined with resin composites or by glass ionomer cements. They may influence the subjacent living pulp. Inflammation and formation of tertiary dentin are the principal evidences, detectable only after histological investigation on demineralized sections. Caries lesions may be active or inactive. About 60 % of the elderly had one or more active lesions, whereas 70 % had more than eight filled carious inactive or active surfaces (Fejerskov et al., Caries Res 25:385–391, 1991). Non-carious cervical lesions (NCCL) are predominant lesions at the junction between the crown and root. In addition, these erosions may also spontaneously remineralize. Tissue regeneration may result from reprecipitation due to salivary minerals.
14.1 Abfraction: Non-carious Cervical Lesions
Abfraction lesions are typically shaped as a wedge-shaped tissue defect (Grippo 1991). The lesion is also designated in different reports under the name of erosion, abrasion, chemical abrasion, and denudation. The concept that occlusal loading could cause cervical stress and consequently may induce a loss of cervical tooth structure has gained over all the other terminology. Some data demonstrate that theoretical stress concentration occurs at cervical areas of the teeth (Shetty et al. 2013). In addition, the term of toothbrush abrasion or toothbrush abuse should be the best and preferred to bruxism (Sarode and Sarode 2013).
Non-carious cervical lesions (NCCL) are caused by occlusal biomechanical forces. Using an appropriate computer program (the finite element method), the authors came to the conclusion that action of occlusal forces, especially paraxial ones, leads to significant stress in the cervical part of the tooth. Abfraction lesions result from the stress in the cervical sub-superficial enamel layer, which is almost five times higher compared with the superficial enamel (Jakupovic et al. 2014). However, brushing is also an important factor associated with NCCL, whereas the occlusal wear seems to play a minor role (Sadaf and Ahmad 2014).
The exposed cervical dentin often displays hypersensitivity (West et al. 2013). The current pain mechanism of dentin hypersensitivity (DHS) seems to be the hydrodynamic theory. Evidence demonstrates odontoblasts express mechano- and/or thermosensitive transient receptor potential ion channels (TRPV1, TRPV2, TRPV3, TRPV4, TRPM3, KCa, and TREK-1). Movements of dentinal fluids within tubules may represent a unique mechano-sensory system with odontoblast acting as sensor cells.
14.2 Pulpal Regeneration
The strategy is to use the intact ECM of pulp cells to induce the specific differentiation of bone marrow-derived mesenchymal stem cells. Tissue engineering requires a triad of cells, scaffolds, and growth factors, leading to pulp regeneration. Pulp vascularization and specialized innervation are considered as crucial for serving as mechano-transducer, providing immediate bacterial response to bacterial insult. Structural proteins and growth factors have been identified in the dental pulp including glucose-regulated protein 78 and TGF-β receptor interacting protein 1, displaying extracellular and intracellular functions. Biomimetic scaffolds induce the differentiation and regeneration of pulp tissue. Vascular endothelial growth factor (VEGF) implanted subcutaneously in nude mice promotes vascularization (Ravindran and George 2015).