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Nanoindentation of Tooth Tissues
Published in Michelle L. Oyen, Handbook of Nanoindentation with biological applications, 2019
Cementum is a thin layer of dental calcified tissue that covers the tooth root by firmly adhering to dentin. Similar to bone tissue, it consists of an inorganic component (65 wt%) mainly comprising hydroxyapatite, an organic component of collagen type I (23 wt%) and the remainder is water (12 wt%). Based on the presence or absence of cells, cementum is grouped into cellular and acellular cementum. The cellular cementum develops a relatively thicker layer on the apical third of the root particularly the outer region, while the acellular cementum, which is more highly calcified, but structureless, covers the cervical two-thirds of the root. The fibers found in cementum could be extrinsic (Sharpey) fibers from periodontal ligaments, or intrinsic fibers originating from cementoblasts, or both types of fibers. The cementum facilitates the attachment of collagen fibers of periodontal ligament to tooth root, whereby the tooth is physically maintained and supported in an alveolar socket.27 Cementum responds to mechanical loadings to which the tooth is subjected, and is continuously modified through life. Excessive forces may lead to a pathological condition resulting in either a resorption or a hyperplasia of the cementum. Dental disease such as caries can affect the cementum as well as other pathologic conditions involving dental pulp and periodontium. Chemical substances from dental procedures may also initiate pathosis in the cementum.
Biomaterials and Immune Response in Periodontics
Published in Nihal Engin Vrana, Biomaterials and Immune Response, 2018
Sivaraman Prakasam, Praveen Gajendrareddy, Christopher Louie, Clarence Lee, Luiz E. Bertassoni
Periodontics is a specialty of dentistry that deals with the prevention, diagnosis and treatment of periodontal diseases and peri-implant diseases. In addition, periodontists, the dental specialty practitioners of periodontics, perform other surgical procedures, examples of which include placement of dental implants and soft tissue surgical procedures, which enhance dental aesthetics and function. The term periodontium describes the supporting structures of a tooth. It includes the gingiva, cementum, periodontal ligament and alveolar bone.1 The gingiva is the outermost soft tissue layer that surrounds a tooth. The cementum is a calcified hard tissue deposit on the tooth surface, which allows periodontal ligament fibre insertion. The periodontal ligament is a well-organised fibrous structure that anchors the teeth through the cementum to the underlying alveolar bone. The alveolar bone is the supporting bone that surrounds the teeth.1 The periodontium, particularly the gingiva, protects the underlying tissues by acting as a barrier against the harsh external environment of the oral cavity. It not only acts as a physical barrier, but has a robust innate and adaptive immune mechanism that provides a dynamic biological barrier.
Gene Therapy in Oral Tissue Regeneration
Published in Vincenzo Guarino, Marco Antonio Alvarez-Pérez, Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Fernando Suaste, Patricia González-Alva, Alejandro Luis, Osmar Alejandro
Cementum is a thin layer of mineralized tissue covering the tooth root surface, which provides a mineralized interface where the soft-tissue attachment has to be re-established. Also, the cementum matrix is a rich source of many growth factors that influence the activities of various periodontal cell types (Han et al. 2015; Grzesik and Narayanan 2002).
Effect of Nd:YAG and Er:YAG laser tooth conditioning on the microleakage of self-adhesive resin cement
Published in Biomaterial Investigations in Dentistry, 2021
Azita Kaviani, Niloofar Khansari Nejad
The commonly used lasers in dentistry are the Nd:YAG laser with 1064 nm and erbium lasers with 2940 nm wavelength. In these wavelengths, lasers have higher absorption, less penetration depth, and fewer thermal side effects since the energy is absorbed by the tissue absorption mechanism and its associated processes [29]. The water and mineral content and the laser’s energy, power, and wavelength are parameters that lead to different reactions with enamel, dentin, and cementum. The parameters in this study were selected based on previous studies on the morphology and temperature of dentin exposed to leaser irradiations with different intensities and frequencies to achieve the best results in terms of the lowest heat produced in the substrate, low pulpal irritation, and the best bond between the adhesive and tooth structure. Since the 2940-mm wavelength of Er:YAG laser exhibits high absorption in water, it heats the substrate. Therefore, it is necessary to use air-and-water coolant to prevent pulpal damage [15,18,30].
Occlusal load modelling significantly impacts the predicted tooth stress response during biting: a simulation study
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
Harnoor Saini, David C. Ackland, Lulu Gong, Oliver Röhrle
To this end, dental structures, including the first right mandibular molar enamel and dentin, the cortical and cancellous mandibular bone, and a section of the left and right mandibular fossa, were manually segmented from the CT scans using ITK-SNAP (version 2.4.0) (Yushkevich et al. 2006). Since dentin and cementum have similar mechanical properties (Shaw et al. 2004), these materials were combined into one structure. The thickness of the articular discs of the TMJ was defined from the width of the space between the mandibular condyles and the fossae. The periodontal ligament (PDL) geometry was based on the mandibular molar root geometry and defined as a uniform layer with an approximate thickness of 0.20 mm similar to other investigations (e.g. McGuinness et al. 1992; Toms and Eberhardt 2003). The maxillary first molar geometry was segmented from the micro-CT images. The rubber sample used in the biting simulations had dimensions 20x10x5mm (Röhrle et al. 2018).
Effect of locally administered novel biodegradable chitosan based risedronate/zinc-hydroxyapatite intra-pocket dental film on alveolar bone density in rat model of periodontitis
Published in Journal of Biomaterials Science, Polymer Edition, 2018
Deepak Kumar Khajuria, Saadath Fathima Zahra, Rema Razdan
Histological sections from the healthy group showed normal architecture of dentin, cementum, periodontal ligament and the alveolar bone tissues. Sections from the untreated periodontitis group revealed inflammatory cell infiltration coupled with severe destruction of the dentine, periodontal ligament, cementum and alveolar process with multiple resorption foci along the bone surface (Figure 7(A–B)). In contrast, the histological appearance of the alveolar bone in the periodontitis group treated with CRZHDF (both) and chitosan film showed restored architecture of trabecular bone with well-connected bone matrix and small medullary spaces (Figure 7(C–E)). The CRZHDF groups also showed restored architechure of dentine, periodontal ligament and cementum. Histological findings revealed that treatment with all therapeutic interventions increased alveolar bone formation and suppressed periodontitis induced alveolar bone resorption, correlating with the radiographic analysis.