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[A Phd completed 4. Interactions between root canal irrigants, sealers and dentin].
Neelakantan, P, Shemesh, H, Wesselink, P
Nederlands tijdschrift voor tandheelkunde. 2016;(9):425-7
Abstract
In the field of endodontology, antibacterial activity of irrigants has been investigated many times. The influence of these solutions on the bonding of root canal sealers, however, has hardly been studied. The objective of this doctoral research was to determine the interactions between root canal sealers and root dentin, and to determine the influence of irrigants on these interactions. The various studies revealed that irrigants have an influence on the bonding of sealers based on epoxy resin, calcium hydroxide, silicones and calcium silicate. In the case of a sealer based on epoxy resin (AH Plus), the irrigation protocol had an influence on the bond strength (adhesion) on dentin, by means of which the seal was also improved. The results of this research produced better insights into the mechanisms at play in the adhesive properties of root canal sealers. Eventually, this might result in improved treatment outcomes of root canal treatments.
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[Updates on rickets and osteomalacia. dental diseases in rickets].
Kubota, T
Clinical calcium. 2013;(10):1497-502
Abstract
Rickets is characterized by mineralization defect in bone and cartilage. X-linked hypophosphatemic rickets (XLH) is the most common form of inherited rickets. Mineralization defect is observed in dentin as well as in bone and cartilage in XLH. The dominant feature is the occurrence of infectious periradicular abscesses on deciduous and permanent teeth, not associated with trauma or decay. Dental care including the maintenance of good oral hygiene and periodical examinations should be performed. A preventive sealing of occlusal surfaces can be considered. Endodontic treatment or extraction are carried out in the presence of periradicular abscesses. Further studies are necessary for elucidating mechanisms of dentin mineralization defect and the occurrence of periradicular abscesses and for developing preventive and curative measures in XLH.
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Tooth dentin defects reflect genetic disorders affecting bone mineralization.
Opsahl Vital, S, Gaucher, C, Bardet, C, Rowe, PS, George, A, Linglart, A, Chaussain, C
Bone. 2012;(4):989-97
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Abstract
Several genetic disorders affecting bone mineralization may manifest during dentin mineralization. Dentin and bone are similar in several aspects, especially pertaining to the composition of the extracellular matrix (ECM) which is secreted by well-differentiated odontoblasts and osteoblasts, respectively. However, unlike bone, dentin is not remodelled and is not involved in the regulation of calcium and phosphate metabolism. In contrast to bone, teeth are accessible tissues with the shedding of deciduous teeth and the extractions of premolars and third molars for orthodontic treatment. The feasibility of obtaining dentin makes this a good model to study biomineralization in physiological and pathological conditions. In this review, we focus on two genetic diseases that disrupt both bone and dentin mineralization. Hypophosphatemic rickets is related to abnormal secretory proteins involved in the ECM organization of both bone and dentin, as well as in the calcium and phosphate metabolism. Osteogenesis imperfecta affects proteins involved in the local organization of the ECM. In addition, dentin examination permits evaluation of the effects of the systemic treatment prescribed to hypophosphatemic patients during growth. In conclusion, dentin constitutes a valuable tool for better understanding of the pathological processes affecting biomineralization.
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Effect of sodium hypochlorite on dentine mechanical properties. A review.
Pascon, FM, Kantovitz, KR, Sacramento, PA, Nobre-dos-Santos, M, Puppin-Rontani, RM
Journal of dentistry. 2009;(12):903-8
Abstract
OBJECTIVES The aim of this study was to carry out a review on the effect of sodium hypochlorite (NaOCl) on the mechanical properties of root dentine. DATA/SOURCES The authors searched the Cochrane Library, Embase, PubMed and the Web of Science for papers published from 1984 to 2008. The main search terms used were: dentine, root canal dentine, sodium hypochlorite, mechanical analysis, elastic modulus, hardness, roughness, flexural strength, compressive strength. STUDY SELECTION The inclusion criteria were studies that evaluated the effect of NaOCl solution, used as an irrigant in endodontics, on the mechanical properties of root dentine. Those studies that were considered to be unrelated to the question addressed, that had investigated NaOCl as a deproteinizing agent, had not evaluated the effect of NaOCl on the mechanical properties of dentine, and that indirectly verified the effect of NaOCl on endodontically treated teeth were excluded. The selected papers were assigned to a score (A-C), according to predetermined criteria. A total of 16 papers were selected, and nine papers were included in the critical appraisal. Five papers were classified as grade A, 4 as grade B, and no paper was classified as grade C. CONCLUSIONS Based on this review, the authors suggest that there is strong evidence showing that sodium hypochlorite adversely alters the mechanical properties of root dentine, when used as an endodontic irrigant.
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Hereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia.
Barron, MJ, McDonnell, ST, Mackie, I, Dixon, MJ
Orphanet journal of rare diseases. 2008;:31
Abstract
The hereditary dentine disorders, dentinogenesis imperfecta (DGI) and dentine dysplasia (DD), comprise a group of autosomal dominant genetic conditions characterised by abnormal dentine structure affecting either the primary or both the primary and secondary dentitions. DGI is reported to have an incidence of 1 in 6,000 to 1 in 8,000, whereas that of DD type 1 is 1 in 100,000. Clinically, the teeth are discoloured and show structural defects such as bulbous crowns and small pulp chambers radiographically. The underlying defect of mineralisation often results in shearing of the overlying enamel leaving exposed weakened dentine which is prone to wear. Currently, three sub-types of DGI and two sub-types of DD are recognised but this categorisation may change when other causative mutations are found. DGI type I is inherited with osteogenesis imperfecta and recent genetic studies have shown that mutations in the genes encoding collagen type 1, COL1A1 and COL1A2, underlie this condition. All other forms of DGI and DD, except DD-1, appear to result from mutations in the gene encoding dentine sialophosphoprotein (DSPP), suggesting that these conditions are allelic. Diagnosis is based on family history, pedigree construction and detailed clinical examination, while genetic diagnosis may become useful in the future once sufficient disease-causing mutations have been discovered. Differential diagnoses include hypocalcified forms of amelogenesis imperfecta, congenital erythropoietic porphyria, conditions leading to early tooth loss (Kostmann's disease, cyclic neutropenia, Chediak-Hegashi syndrome, histiocytosis X, Papillon-Lefevre syndrome), permanent teeth discolouration due to tetracyclines, Vitamin D-dependent and vitamin D-resistant rickets. Treatment involves removal of sources of infection or pain, improvement of aesthetics and protection of the posterior teeth from wear. Beginning in infancy, treatment usually continues into adulthood with a number of options including the use of crowns, over-dentures and dental implants depending on the age of the patient and the condition of the dentition. Where diagnosis occurs early in life and treatment follows the outlined recommendations, good aesthetics and function can be obtained.
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Factors affecting in vitro bond strength of bonding agents to human dentin.
Powers, JM, O'Keefe, KL, Pinzon, LM
Odontology. 2003;(1):1-6
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Abstract
Four generations of total-etch (fourth, fifth) and self-etching (sixth, seventh) bonding agents for use with resin composites are commercially available in the United States. Innovations in bonding agents include: filled systems, release of fluoride and other agents, unit dose, self-cured catalyst, option of etching with either phosphoric acid or self-etching primer, and pH indicators. Factors that can affect in vitro bond strength to human dentin include substrate (superficial dentin, deep dentin; permanent versus primary teeth; artificial carious dentin), phosphoric acid versus acidic primers, preparation by air abrasion and laser, moisture, contaminants, desensitizing agents, astringents, and self-cured restorative materials. This article reviews studies conducted at the Houston Biomaterials Research Center from 1993 to 2003. Results show that in vitro bond strengths can be reduced by more than 50% when bonding conditions are not ideal.
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Dentine bonding agents--a review of adhesion to dentine.
Moodley, D, Grobler, SR
SADJ : journal of the South African Dental Association = tydskrif van die Suid-Afrikaanse Tandheelkundige Vereniging. 2002;(6):234-8
Abstract
Although constant innovation has improved the performance of dentine adhesives, the true mechanism of resin adhesion to dentine is still not clear and the optimal dentinal surface pretreatment has yet to be determined for adhesive integrity of resin to dentine. The integrity of the collagen fibrils left exposed upon acid etching seem to play a major role in the mechanism of adhesion and intermingling of the adhesive monomers with the filigree of collagen fibers or hybrid layer should be considered the paramount dentine bonding mechanism. Definite trends are emerging but more research is necessary before general conclusions can be made about the functions of different bonding agents. The all-in-one self-etching/self-primer bottle systems are relatively new to the market and need more research before they can be advocated as the agent of choice.