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At least 19 recordsLinked to original sources
PubMed1979

Transmission and control of dentinal pain: resin impregnation for the desensitization of dentin.

With the exception of direct electrical stimulation, it seems that all procedures known to produce dentinal pain may mechanically distort the structure of pain-sensitive nerves in the pulp and predentinal area and that this effect is mediated by a hydrodynamic link. Nature may contribute to insensitive dentin by: production of irregular, atubular dentin at the pulpal wall; obliteration of dentinal tubules by sclerosis; and mineralization of a superficial layer, pellicle or plaque, at the exposed surface. Few clinical methods are capable of accelerating these mechanisms. A technique of resin impregnation for the desensitization of exposed dentin has been presented. After proper pretreatment, that includes drying the dentin surface, resin tags can be obtained in the outer part of the dentinal tubules and may immediately and permanently relieve dentinal pain. This technique seems to be a good alternative to other methods, especially for patients with occlusal or incisal exposures caused by abrasion, grinding, or fracture, in which other methods cannot provide immediate and long-lasting desensitization.

Acid Etching, Dental↗
PubMed1977

Effect of a carious dentin softener on the dentin and pulp.

The application of GK-101 to carious dentin softens the first or outer layer which contains denatured collagen. The second or inner layer of carious dentin, containing normal collagen fibers, is unaffected. The pulps of dog teeth were not affected by applying the solution to freshly prepared sound dentin.

Animals↗
PubMed1977

Microscopy of the junctional region between human coronal primary and secondary dentine.

The juction between human primary dentine and regular and irregular secondary dentine was examined with a number of different light and electron microscopic techniques. In decalcified material, a narrow band along the innermost surface of the primary dentine stained intensely. The walls of the tubules within the band stained intensely, whereas the tubular walls within the bulk of the primary dentine were not stained. Generally, the walls of the tubules in both types of secondary dentine were also preferentially stained. Although not readily apparent in ground sections, observations of thin sections revealed a dramatic reduction in the number of tubules in regular secondary dentine. Generally, the radiodensity of the intertubular matrix was the same in primary and secondary dentine and the intensely stained band was not seen radiographically. The pulpal ends of the tubules in primary dentine were often occluded with a material having the same radiodensity as peritubular matrix. Both patent and occluded tubules were seen in irregular secondary dentine. Scanning electron microscopy of acid-etched specimens of secondary dentine revealed that some tubules had irregular walls of highly mineralized matrix which was less acid-soluble then the peritubular matrix of primary dentine.

Cuspid↗
PubMed1979

Innervation of different parts of the predentin and dentin in young human premolars.

The innervation of the predentin and inner part of the mineralized dentin was studied at the ultrastructural level in ten premolars. Each tooth was divided into fifteen different parts, each containing odontoblasts, predentin and dentin. It was found that the innervation in the coronal dentin was more compact than in the root dentin. Within the coronal dentin itself, the most densely innervated area was the dentin covering the pulp horns. No nerves were identified more than 100 microns from the pulp-dentinal border. No nervous structures were found in the mineralized dentin of the root. Nervous structures which seemed to have no connection with the odontoblastic processes were frequently observed in the predentin of the root. Signs of degeneration of the nervous structures of the predentin of the root was also a common finding. The observation that the intradentinal nerves were confined to the predentin and the most pulpal part of the dentin supports the theory that surface stimulation on dentin has an indirect effect on the nerves activated by movements in the liquid of the dentinal tubules.

Adolescent↗
PubMed1977

On the state of anionic groups of demineralized matrices of bone and dentine.

Calcium-binding and biochemical studies have been applied to characterize the state of the carboxylate and protein-bound phosphate groups in the EDTA-demineralized matrices of rat bone and dentine. The organic phosphate and carboxylate content of demineralized bone is virtually identical to that of purified steer skin collagen whereas demineralized dentine has a significantly higher phosphate and carboxylate content, presumably due to the presence of an acidic non-collagenous phosphoprotein. Two classes of calcium-binding sites can be detected in demineralized bone, demineralized dentine, and purified, reconstituted collagen. The number of strong calcium-binding sites correlates with the number of protein-bound phosphate groups. Depending on the preparative procedure, seven to nine such sites (per collagen molecule) are present in dentine, and one to two in the purified reconstituted collagen and in bone. The binding constant for the dentinal sites (1.1 X 10(4) M-1), however, is 20 times greater than that for bone or reconstituted collagen fibrils from skin. We tentatively conclude that the strong calcium-binding site in bone and reconstituted collagen is of the form protein-PO-4Ca++ whereas in dentine it is of the form protein (formula: see text); the weak binding sites in bone and dentine are of the form protein-COO-Ca++; and that approximately 160 of the 217 carboxylate groups of the collagen molecules of dentine or bone are present as electrostatic linkages of the form protein-COO-+H3N-protein.

Animals↗
PubMed2026

Proteomic profile of the dentine pellicle modified with plant polyphenols and fluoride.

OBJECTIVES: Despite its protective role, the dentine pellicle has rarely been studied, therefore we aimed to map out the proteomic profile of in vitro dentine pellicles before and after modification. MATERIALS AND METHODS: A total of 135 human dentine specimens were prepared. After initial pellicle formation with 150 µl pooled human saliva (37 °C, 30 min), the dentine specimens were immersed in one of 9 pellicle modification solutions (2 ml/specimen): deionized water (non-modified pellicle), SnCl2/NaF/AmF (commercial solution containing 800 ppm Sn2+ and 500 ppm F-), NaF solution (500 ppm F- ), and six polyphenol solutions (2 mg / ml) with or without 500 ppm F-: blueberry extract (BBE and BBE + F-), green tea extract (GTE and GTE + F-) and grape seed extract (GSE and GSE + F-). After another aliquot of saliva (150 µl, 37 °C, 60 min), the pellicles were harvested with sodium dodecyl sulphate by rubbing with cotton balls, and taken to proteomic analyses by Liquid Chromatography-Tandem Mass Spectrometry after tryptic digestion. RESULTS: A total of 382 proteins were identified in all the proteomic analyses for all groups. Pellicle modification with fluoride, either NaF or SnCl2/NaF/AmF, led to the presence of 12 or 14 exclusive proteins, respectively, whereas modification with the solutions containing polyphenols presented less exclusive proteins (4-6 proteins). The number of exclusive proteins was even lower for when polyphenols and fluoride (GTE + F- and GSE + F-) were used, with lower abundance of proteases. CONCLUSIONS: We conclude that NaF and SnCl2/NaF/AmF significantly modify the proteome of the dentine pellicle. The combination of fluoride with polyphenols further lowers the abundance of proteins and proteases, which explains the positive effect of these solutions on the dentine pellicles. CLINICAL RELEVANCE: Plant extract solutions with fluoride can significantly modify the proteomic structure of the dentine pellicle, which clarifies the mechanism of action of polyphenols on the protection of dentine demineralization.

Humans↗
PubMed1975

The diameter and number of dentinal tubules in rat, cat, dog and monkey. A comparative scanning electron microscopic study.

The aim of the study was to investigate in commonly used experimental animals the pulpal wall and the dentin with special reference to the number and diameter of the dentinal tubules. The coronal dentin of a total of 26 permanent, intact teeth from rat, cat, dog and monkey was fractured experimentally. The calculations were based on the study of about 150 scanning electron microscope (SEM) photographs of fractured surfaces and of the pulp chamber wall. The number of dentinal tubules per unit area was calculated and the tubule diameter was measured at various distances from the pulp. The tubules were found to be widest at the pulpal wall, where the mean diameter ranged form 1.7 to 2.8 mum, the highest value being found in monkey and the lowest in the incisors of rat. In the middle part of the dentin the mean diameter varied from 1.0 to 1.3 mum and at the periphery it was 0.6 to 0.9 mum. The largest number of tubules per unit area was found immediately incisal of the pulp horn and the smallest number cervically, near the enamel. At the pulpal wall the mean number of the tubules ranged from 50,000 to 90,000/mm2, in the middle of the dentin it was between 37,000 and 50,000/mm2 and at the periphery it was between 10,000 and 25,000/mm2. In all species examined the dentinal tubules showed a straight course, except in incisors of rat, where local irregularities were seen. A comparison was also made between the species studied and homo with respect to the number and width of the dentinal tubules.

Animals↗
PubMed1975

Mineralization of dentin, bone and tendon in vitro.

Bovin dentin, bone and tendon slices, and rat bone, readily mineralize to variable degrees after demineralization by (EDTA) at pH 7.4, but they fail to mineralize after dimeralzation with acetic acid (HAc) at pH3.0. The demineralized dentin, but neither bone nor tendon, contained organically bound phosphate. The EDTA-demineralized dentin contained less phosphate than HAc-demineralized dentin. HAc-demineralized rat dentin contained high levels of phosphate. Since the EDTA- and HAc-demineralized rat dentin contained widely different levels of phosphate, yet both mineralized, it was concluded that phosphoprotein had little effect on nucleation. The reason why HAc-demineralized tissue other than rat dentin failed to nucleate and mineralize was not clarified.

Acetates↗
PubMed1977

The morphologic relationship between dental resins and etched dentin.

A scanning electron microscopic examination of the interface between etched dentin and several different commercial resins showed that pretreatment with othophosphoric acid enlarged the dentinal tubules facilitating penetration of the resin. The depth of penetration increased from approximately 0.2 mm to 2.0 mm when dentin was dried for 24 hours compared to using the normal clinical protocol. The hydration of dentin and/or the presence of dentinal fluid probably influences the degree of resin penetration. While penetration would provide a means of mechanical retention of resin it would probably do so at the expense of dentin and pulp viability particularly where remaining dentin thickness is less than 1.0 mm. Penetration of toxic resin would account in part for the enhanced inflammatory pulpal response observed following application of acid etch restorative procedures.

Absorption↗
PubMed1978

Vital staining of coronal dentin in monkey teeth.

Vital staining of monkey incisor teeth with the incisal dentin exposed to the oral environment by attrition was carried out, with the use of a number of dyes (pH and redox indicators). There was a distinct staining of the coronal dentin, regardless of which dye was introduced into the pulpal cavity. The exposed dentin was stained like the unaffected dentin, with the exception of a narrow centrally located zone that extended from the tip of the original pulp horn to the incisal edge of the tooth. The suggestion is that this zone is not unstained because of exposure of the dentin to the oral environment, but because it coincides with an area of the tissue where the pulpal ends of the dentinal tubules are blocked by atubular hard tissue normally laid down in the pulp horn of incisor teeth.

Animals↗
PubMed1978

Dentinal crazing and interpin distance.

All three types of self-threading plus cause dentinal crazing. The frequency and degree of damage done to the dentin varies significantly between the three types of pins and depends upon the differences in the diameters of the drill and the pin. When two or more pins are placed in dentin, the potential for dentinal damage increases. Minikin pins (0.019-inch diameter) caused the least damage, in terms of both degree and frequency. The optimum and safe interpin distance using Minikin pins suggested by this study is 3 mm. Minim and Regular pins (0.023- and 0.031-inch diameters, respectively) caused more injury than Minikin pins. The Regular pins showed more damaging effects on dentin than Minim pins, both in terms of degree and frequency. On the basis of this study, the minimum interpin distance using Minim or Regular pins should be 5 mm. These minimum interpin distances are applicable only in situations where the dentin is not dehydrated or embrittled due to endodontic treatment. In teeth that have been endodontically treated, it would be advisable to use only the smallest self-threading pins and possibly increase the interpin distance if two or more pins are to be used.

Dental Pins↗
PubMedDate not supplied

Electron microscope comparison of freeze-substitution and conventional chemical fixation of undecalificied human dentin.

Within the stated limits of cell fine structure preservation and within the observed anatomical limits specified in the Results and Discussion sections, a freeze-substitution method using an ethylene glycol-Hank's solution eutectic mixture with a glutaraldehyde additive can be used to effectively prepare undecalcified human dentin for electron microscopy. The ultrastructual appearance of the odontoblast cell body and the odontoblastic process subjected to freeze-substitution differs from that seen with conventional chemical fixation. Artifacts produced by freeze-substitution differ in appearance and frequency of occurrence from those produced by glutaraldehyde-osmium tetroxide sequential double fixation. The cellular component of dentin shows greater structural preservation of protein when it is subjected to freeze-substitution that when it is prepared by conventional chemical fixation. The absence of ice crystal defects in the odontoblastic process in calcified dentin and the presence of ice crystal defects in the odontoblast cell body suggest that intracellular water in the odontoblastic process in the calcified dentin may exist in a more highly structured state than intracellular water in the odontoblast cell body. If intracellular water exists in a more highly structured state in the odontoblastic process of the calcified dentin than in the cell body, the ratio of protein molecules to cytoplasmic volume may be greater in the odontoblastic process than in the cell body. After glutaraldehyde-osmium tetroxide sequential double fixation, the use of graded alcohol dehydration obtained cell fine structure preservation and artifact control superior to that obtained by use of ethylene glycol cryodehydration. Further refinements of the freeze-substitution technique, as it applies to the preparation of undecalcified human dentin, are necessary to increase the amount of cellular preservation, to decrease the number of ice crystal artifacts, and to improve the overall quality of cell fine structure preservation.

Adolescent↗
PubMed1977

Noncollagenous proteins of a rat dentin matrix possessing bone morphogenetic activity.

An insoluble preparation of rat dentin matrix was shown to possess bone morphogenetic protein (BMP) activity, i.e. the capacity to induce the formation of catilage and bone when implanted intramuscularly. Since BMP activity was previously attributed to noncollagenous proteins (NCP) of bone and dentin, the nature of NCP of the rat dentin was examined. After treatment of the matrix with purified bacterial collagenase, three NCP were solubilized concomitantly with digestion of the dentin collagen to smaller peptides. The three proteins were separated by anion-exchange chromatography on DEAE-cellulose. Two of the NCP were rich in asparate, glutamate, glycine, serine, and alanine, and thus displayed compositions similar to acidic proteins of other connective tissues. The third NCP was shown by amino acid composition to be the aspartate, serine-rich phosphoprotein, which occurs mostly in a soluble form in rat dentin. This observation supports the view that a portion of dentin phosphotprotein is firmly bound.

Amino Acids↗
PubMed1977

Collagen biochemistry of the two layers of carious dentin.

The amino acid composition and intermolecular cross links of collagen fibers in the two layers of carious dentin, differentiated by a 0.5% basic fuchsin-propylene glycol-stain, were biochemically investigated. No difference in the pattern of amino acid composition of collagen fibers was found between the first and second layers of carious dentin and the sound dentin. However, obvious differences in the intermolecular cross links of collagen fibers were found between the three layers. Namely, compared with the sound dentin, the second layer of carious dentin had decreased cross links and increased precursors. This change is considered to be reversible. Contrastingly, in the first layer, both the cross links and the precursors remarkably decreased. In addition, the hexitollysines (protein-saccharide compounds probably related to bacterial metabolism) were found and several peaks of unknown materials appeared. This indicates irreversible destruction of cross-linkage in the first layer of carious dentin.

Amino Acids↗
PubMed1979

A classification of dysplastic forms of dentin.

Considerable effort has been made in the past to describe the morphologic changes in dentin which characterize various developmental disturbances of teeth. However, there appears to be no previous attempt to describe the spectrum of changes which may be exhibited by abnormal dentin. This paper presents a classification of dysplastic forms of dentin with definitions and illustrations of each abnormality. The classification was derived from reviewing the literature and from a study of 82 odontomas, examples of specific developmental disorders of dentin, regional odontodysplasia, and systemic conditions affecting dentin.

Dentin↗