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Dental Clinics of North America Oct 2017This article provides a brief review of recent investigations concerning the structure and properties of the tooth. The last decade has brought a greater emphasis on the... (Review)
Review
This article provides a brief review of recent investigations concerning the structure and properties of the tooth. The last decade has brought a greater emphasis on the durability of the tooth, an improved understanding of the fatigue and fracture behavior of the principal tissues, and their importance to tooth failures. The primary contributions to tooth durability are discussed, including the process of placing a restoration, the impact of aging, and challenges posed by the oral environment. The significance of these findings to the dental community and their importance to the pursuit of lifelong oral health are highlighted.
Topics: Aging; Dental Enamel; Dentin; Humans; Tooth
PubMed: 28886762
DOI: 10.1016/j.cden.2017.05.001 -
International Journal of Molecular... Feb 2020Sonic hedgehog (Shh) is a secreted protein with important roles in mammalian embryogenesis. During tooth development, Shh is primarily expressed in the dental... (Review)
Review
Sonic hedgehog (Shh) is a secreted protein with important roles in mammalian embryogenesis. During tooth development, Shh is primarily expressed in the dental epithelium, from initiation to the root formation stages. A number of studies have analyzed the function of Shh signaling at different stages of tooth development and have revealed that Shh signaling regulates the formation of various tooth components, including enamel, dentin, cementum, and other soft tissues. In addition, dental mesenchymal cells positive for Gli1, a downstream transcription factor of Shh signaling, have been found to have stem cell properties, including multipotency and the ability to self-renew. Indeed, Gli1-positive cells in mature teeth appear to contribute to the regeneration of dental pulp and periodontal tissues. In this review, we provide an overview of recent advances related to the role of Shh signaling in tooth development, as well as the contribution of this pathway to tooth homeostasis and regeneration.
Topics: Animals; Dental Enamel; Dental Pulp; Epithelium; Hedgehog Proteins; Homeostasis; Humans; Mesenchymal Stem Cells; Odontogenesis; Signal Transduction; Tooth; Tooth Root; Zinc Finger Protein GLI1
PubMed: 32111038
DOI: 10.3390/ijms21051587 -
Indian Journal of Dental Research :... 2020Abfraction is a loss of tooth structure along the gingival margin and manifests with different clinical appearances. It has multifactorial etiology and may occur due to... (Review)
Review
BACKGROUND
Abfraction is a loss of tooth structure along the gingival margin and manifests with different clinical appearances. It has multifactorial etiology and may occur due to normal and abnormal tooth function and may also be accompanied by pathological wear, such as abrasion and erosion. The theory behind the abfraction is that the tooth flexure in the cervical area is caused due to occlusal compressive forces and tensile stresses. This results in the fractures in the hydroxyapatite (HA) crystals. It is also caused by the low packing density of the Hunter-Schreger band (HSB) at the cervical area. Unfortunately, there is a lack of evidence regarding the outcome of abfraction with or without intervention. The aim of this review is to collect clinical information from the literature and discuss the etiology, pathogenesis, clinical representation, and management. Also, search databases for clinical studies that describe the role of sclerotic dentine in non-carious cervical lesions (NCCLs) are becoming a clinical challenge.
METHODS
The literature was searched that described the etiology, pathogenesis, clinical representation, and management of the abfraction lesions. Also, a specific question regarding the formation of sclerotic dentin in the NCCL lesion was described and searched for evidence that challenges etching, bonding, and successfully restoring NCCLs. The databases PUBMED, SCOPUS, MEDLINE, WEB of SCIENCE, and EMBASE were searched using the key terms. The inclusion criteria were the randomized controlled clinical trial, cohort studies, and cross-sectional studies that aimed at determining the role of sclerotic dentine in NCCLs and its effect on etching, bonding.
RESULTS
One clinical study was retrieved according to the PRISMA flowchart and PICO format. The longer etching time, total-etch adhesive system, and EDTA pre-treatment of the sclerotic dentin of cervical wedge-shaped defects could improve the bonding strength in lesions like NCCL's.
CONCLUSION
In conclusion, clinical challenges that occur due to NCCLs are better managed by a proper understanding of factors like etiopathogenesis, ultra-structure of enamel, and dentine and their effect on the bonding of restorations of the tooth.
Topics: Cross-Sectional Studies; Dental Enamel; Dentin; Humans; Tooth Cervix; Tooth Diseases
PubMed: 32436913
DOI: 10.4103/ijdr.IJDR_863_18 -
Development (Cambridge, England) Feb 2017The tooth root is an integral, functionally important part of our dentition. The formation of a functional root depends on epithelial-mesenchymal interactions and... (Review)
Review
The tooth root is an integral, functionally important part of our dentition. The formation of a functional root depends on epithelial-mesenchymal interactions and integration of the root with the jaw bone, blood supply and nerve innervations. The root development process therefore offers an attractive model for investigating organogenesis. Understanding how roots develop and how they can be bioengineered is also of great interest in the field of regenerative medicine. Here, we discuss recent advances in understanding the cellular and molecular mechanisms underlying tooth root formation. We review the function of cellular structure and components such as Hertwig's epithelial root sheath, cranial neural crest cells and stem cells residing in developing and adult teeth. We also highlight how complex signaling networks together with multiple transcription factors mediate tissue-tissue interactions that guide root development. Finally, we discuss the possible role of stem cells in establishing the crown-to-root transition, and provide an overview of root malformations and diseases in humans.
Topics: Animals; Bone Morphogenetic Proteins; Fibroblast Growth Factors; Hedgehog Proteins; Humans; Mice; Mice, Mutant Strains; Models, Dental; Odontogenesis; Signal Transduction; Stem Cells; Tooth Abnormalities; Tooth Crown; Tooth Root; Transforming Growth Factor beta; Wnt Signaling Pathway
PubMed: 28143844
DOI: 10.1242/dev.137216 -
Journal of Dental Research Sep 2021Biomineralization of enamel, dentin, and bone involves the deposition of apatite mineral crystals within an organic matrix. Bone and teeth are classic examples of... (Review)
Review
Biomineralization of enamel, dentin, and bone involves the deposition of apatite mineral crystals within an organic matrix. Bone and teeth are classic examples of biomaterials with unique biomechanical properties that are crucial to their function. The collagen-based apatite mineralization and the important function of noncollagenous proteins are similar in dentin and bone; however, enamel is formed in a unique amelogenin-containing protein matrix. While the structure and organic composition of enamel are different from those of dentin and bone, the principal molecular mechanisms of protein-protein interactions, protein self-assembly, and control of crystallization events by the organic matrix are common among these apatite-containing tissues. This review briefly summarizes enamel and dentin matrix components and their interactions with other extracellular matrix components and calcium ions in mediating the mineralization process. We highlight the crystallization events that are controlled by the protein matrix and their interactions in the extracellular matrix during enamel and dentin biomineralization. Strategies for peptide-inspired biomimetic growth of tooth enamel and bioinspired mineralization of collagen to stimulate repair of demineralized dentin and bone tissue engineering are also addressed.
Topics: Amelogenin; Biomineralization; Collagen; Dental Enamel; Dentin
PubMed: 34151644
DOI: 10.1177/00220345211018405 -
Australian Dental Journal Jun 2011Improved dental adhesive technology has extensively influenced modern concepts in restorative dentistry. In light of minimal-invasive dentistry, this new approach... (Review)
Review
Improved dental adhesive technology has extensively influenced modern concepts in restorative dentistry. In light of minimal-invasive dentistry, this new approach promotes a more conservative cavity design, which basically relies on the effectiveness of current enamel-dentine adhesives. Nowadays, the interaction of adhesives with the dental substrate is based on two different strategies, commonly described as an etch-and-rinse and a self-etch approach. In an attempt to simplify the bonding technique, manufacturers have decreased the number of steps necessary for the accomplishment of the bonding procedure. As a consequence, two-step etch-and-rinse and one-step (self-etch) adhesives were introduced and gained rapid popularity in the dental market due to their claimed user-friendliness and lower technique sensitivity. However, many concerns have been raised on the bonding effectiveness of these simplified adhesives, especially in terms of durability, although this tends to be very material dependent. In order to blend all the adhesive components into one single solution, one-step adhesives were made more acidic and hydrophilic. Unfortunately, these properties induce a wide variety of seemingly unrelated problems that may jeopardize the effectiveness and stability of adhesion to the dental substrate. Being more susceptible to water sorption and thus nanoleakage, these adhesives are more prone to bond degradation and tend to fail prematurely as compared to their multi-step counterparts. Incidentally, another factor that may interfere with the bonding effectiveness of adhesives is the technique used for caries removal and cavity preparation. Several tools are on the market today to effectively remove carious tissue, thereby respecting the current trend of minimum intervention. Despite their promising performance, such techniques modify the tooth substrate in different aspects, possibly affecting bonding effectiveness. Altogether, we may conclude that not only the adhesive formulation, but also substrate nature must be taken into account to achieve a stable bonding interface, rendering the restorative treatment more predictable in terms of clinical performance. In this review, we analyse the current theoretical and clinical aspects of adhesion to enamel and dentine, and discuss the diverse possibilities to overcome problems which nowadays still challenge clinicians in their achievement of a more stable and effective bond to tooth enamel and dentine.
Topics: Adhesiveness; Adhesives; Dental Bonding; Dental Cavity Preparation; Dental Enamel; Dental Etching; Dental Stress Analysis; Dentin; Dentin-Bonding Agents; Humans
PubMed: 21564114
DOI: 10.1111/j.1834-7819.2011.01294.x -
Australian Dental Journal Mar 2007The dental pulp is a unique tissue and its importance in the long-term prognosis of the tooth is often ignored by clinicians. It is unique in that it resides in a rigid...
The dental pulp is a unique tissue and its importance in the long-term prognosis of the tooth is often ignored by clinicians. It is unique in that it resides in a rigid chamber which provides strong mechanical support and protection from the microbial rich oral environment. If this rigid shell loses its structural integrity, the pulp is under the threat of the adverse stimuli from the mouth, such as caries, cracks, fractures and open restoration margins, all of which provide pathways for micro-organisms and their toxins to enter the pulp. The pulp initially responds to irritation by becoming inflamed and, if left untreated, this will progress to pulp necrosis and infection. The inflammation will also spread to the surrounding alveolar bone and cause periapical pathosis. The magnitude of pulp-related problems should not be underestimated since their most serious consequence is oral sepsis, which can be life threatening, and hence correct diagnosis and management are essential. Clinicians must have a thorough understanding of the physiological and pathological features of the dental pulp as well as the biological consequences of treatment interventions.
Topics: Dental Pulp; Dental Pulp Diseases; Disease Progression; Humans; Microcirculation; Odontoblasts; Pulpitis; Regional Blood Flow
PubMed: 17546858
DOI: 10.1111/j.1834-7819.2007.tb00525.x -
Journal of Dental Research Feb 2015Dentin can be described as a biological composite with collagen matrix embedded with nanosized hydroxyapatite mineral crystallites. Matrix metalloproteinases (MMPs) and... (Review)
Review
Dentin can be described as a biological composite with collagen matrix embedded with nanosized hydroxyapatite mineral crystallites. Matrix metalloproteinases (MMPs) and cysteine cathepsins are families of endopeptidases. Enzymes of both families are present in dentin and collectively capable of degrading virtually all extracellular matrix components. This review describes these enzymes and their presence in dentin, mainly focusing on their role in dentin caries pathogenesis and loss of collagen in the adhesive hybrid layer under composite restorations. MMPs and cysteine cathepsins present in saliva, mineralized dentin, and/or dentinal fluid may affect the dentin caries process at the early phases of demineralization. Changes in collagen and noncollagenous protein structure may participate in observed decreases in mechanical properties of caries-affected dentin and reduce the ability of caries-affected dentin to remineralize. These endogenous enzymes also remain entrapped within the hybrid layer during the resin infiltration process, and the acidic bonding agents themselves (irrespective of whether they are etch-and-rinse or self-etch) can activate these endogenous protease proforms. Since resin impregnation is frequently incomplete, denuded collagen matrices associated with free water (which serves as a collagen cleavage reagent for these endogenous hydrolase enzymes) can be enzymatically disrupted, finally contributing to the degradation of the hybrid layer. There are multiple in vitro and in vivo reports showing that the longevity of the adhesive interface is increased when nonspecific enzyme-inhibiting strategies are used. Different chemicals (i.e., chlorhexidine, galardin, and benzalkonium chloride) or collagen cross-linker agents have been successfully employed as therapeutic primers in the bonding procedure. In addition, the incorporation of enzyme inhibitors (i.e., quaternary ammonium methacrylates) into the resin blends has been recently promoted. This review will describe MMP functions in caries and hybrid layer degradation and explore the potential therapeutic role of MMP inhibitors for the development of improved intervention strategies for MMP-related oral diseases.
Topics: Cathepsins; Collagen; Dental Bonding; Dental Caries; Dental Materials; Dentin; Disease Progression; Humans; Matrix Metalloproteinase Inhibitors; Matrix Metalloproteinases
PubMed: 25535202
DOI: 10.1177/0022034514562833 -
Journal of Dental Research Jul 2016Cementum is a mineralized tissue covering the tooth root that functions in tooth attachment and posteruptive adjustment of tooth position. During formation of the... (Review)
Review
Cementum is a mineralized tissue covering the tooth root that functions in tooth attachment and posteruptive adjustment of tooth position. During formation of the apically located cellular cementum, some cementoblasts become embedded in the cementoid matrix and become cementocytes. As apparently terminally differentiated cells embedded in a mineralized extracellular matrix, cementocytes are part of a select group of specialized cells, also including osteocytes, hypertrophic chondrocytes, and odontoblasts. The differentiation and potential function(s) of cementocytes are virtually unknown, and the question may be posed whether the cementocyte is a dynamic actor in cementum in comparable fashion with the osteocyte in the skeleton, responding to changing tooth functions and endocrine signals and actively directing local cementum metabolism. This review summarizes the literature with regard to cementocytes, comparing them to their closest "cousins," the osteocytes, where insights gained from osteocyte studies serve to inform the critical examination of cementocytes. The review identifies important unanswered questions about these cells regarding their origins, differentiation, morphology and lacuno-canalicular system, selective markers, and potential functions.
Topics: Animals; Dental Cementum; Humans; Microscopy, Electron, Scanning; Osteocytes; Tooth Root
PubMed: 27029548
DOI: 10.1177/0022034516641898 -
International Journal of Environmental... Jan 2023Orthodontic miniscrews (OM) are widely used in modern orthodontic clinical practice to improve skeletal anchorage and have a high safety profile. A complication at the... (Review)
Review
Orthodontic miniscrews (OM) are widely used in modern orthodontic clinical practice to improve skeletal anchorage and have a high safety profile. A complication at the time of OM insertion is tooth root perforation or periodontal ligament trauma. Rarely, OM injury can cause permanent damage, such as ankylosis, osteosclerosis, and loss of tooth vitality. The aim of this work was to analyze potential risks and dental complications associated with the use of OMs. A search of the PubMed, Cochrane, Web of Science, and Scopus databases was conducted without a time limit using the keywords "orthodontic mini-screw" and "dental damage", resulting in 99 studies. After screening and eligibility, including articles obtained through a citation search, 13 articles were selected. Four studies revealed accidental injuries caused by OM. Most of the damage was localized at the root level and resolved spontaneously with restorative cement formation after prompt removal of the OM, while the pain disappeared. In some cases, irreversible nerve damage, extensive lesions to the dentin-pulp complex, and refractory periapical periodontitis occurred, requiring endodontic and/or surgical treatment. The choice of insertion site was the most important element to be evaluated during the application of OMs.
Topics: Tooth Root; Bone Screws
PubMed: 36674316
DOI: 10.3390/ijerph20021562