bluuebunny/crossref_metadata_2025 huggingface dataset:
Na-K-ATPase in the Enamel Organ: Localization and Possible Roles in Enamel Formation
Authors: Garant P.R. , Sasaki T. , Colflesh P.E.
Published: January 2017

Ouabain-sensitive, K-dependent p-nitrophenyl phosphatase (p-NPPase) activity was localized ultra-Ocytochemically in the lateral plasma membranes of secretory ameloblasts and the stratum intermedium and principally in the papillary layer cells of aldehyde-fixed rat incisor enamel organs by the one-step lead method. Daily intraperitoneal injection of ouabain (250 μg, 500 μg, and 1 mg/100 g body weight) for two weeks reduced p-NPPase activity in the enamel organ cells. However, the degree to which this activity was reduced appeared to vary among the experimental animals. Addition of ouabain to the cytochemical incubation medium completely inhibited p-NPPase activity in the tissues. Although long-term ouabain injection did not result in any morphological alterations of the enamel organ cells, it caused, in part, an appearance of electron-dense, homogeneous matrix-like substances (MS) in the extracellular spaces of the ameloblast layers at both the secretion and maturation stages. In addition, long-term ouabain injection appeared to have resulted in delayed maturation of enamel as measured by energy-dispersive x-ray analysis of Ca and P in surface enamel. These results suggest that Na-K-ATPase of enamel organ cells may participate in the net flow (removal) of organic matrix components and water from the enamel during the maturation stage of enamel formation. It is suggested that this flow is maintained by local osmotic gradients generated by Na-K-ATPase within the papillary layer.
Molecular Cloning of Bovine Amelogenin cDna
Authors: Shimokawa H. , Ogata Y. , Sasaki S. , Sobel M.E. , Mcquillan C.I. , Termine J.D. , Young M.F.
Published: January 2017

Molecular cloning of a bovine amelogenin cDNA was accomplished by construction of a cDNA expression library (λgt11 cDNA library) from the bovine ameloblast mRNA and then screening of the library with antibodies to bovine amelogenins. The complete primary structure of an amelogenin was deduced from cloned cDNA. One of the cDNA clones isolated from a bovine ameloblast phage λgt11 library had an 864-base-pair-long insert that encoded a protein with 216 amino acid residues. This cDNA clone appears to represent the complete coding region of amelogenin mRNA, including a putative AUG initiation codon and a signal peptide sequence. The predicted bovine amelogenin sequence has 87% amino acid homology with murine amelogenin.
Examining the Possible Molecular Origins for Enamel Protein Complexity
Authors: Snead M.L. , Lau E.C.
Published: January 2017

Our strategy was to examine each of the three loci capable of contributing to the observed complexity 0 of mouse amelogenin proteins recovered from forming enamel: the genome (gene); the transcription apparatus (messenger RNA); and the translation apparatus (proteins). Our approach was based on recombinant DNA technology and a complementary DNA (cDNA) clone, pMa5-5, specific to the predominant mouse amelogenin protein. An "artificial ameloblast" was engineered based on pMa5-5 and the resulting synthetic products compared to those from authentic ameloblasts. First, the genome probably is not responsible for amelogenin complexity: Southern analysis indicates that the amelogenin gene exists as a single copy in either differentiated dental tissue or germ line tissue. Thus, ectomesenchymal-derived instructive signals for ameloblast differentiation do not lead to re-arrangement or amplification of the amelogenin gene. Next, using nucleic acid hybridization techniques, we examined messenger RNA from mouse ameloblasts. Northern analysis of authentic mRNA from mouse ameloblasts, with either the intact or 3'-end of pMa 5-5 used as the reporter molecule, indicates that only one size class of mRNA was detectable. We conclude that at the sensitivity of this assay there is no evidence for multiple mRNAs. Last, "artificial ameloblasts" were engineered so that the translation apparatus could be examined as a source of amelogenin complexity. Capped, artificial mRNAs were constructed to the pMa 5-5 template and used to program the synthesis of amelogenin polypeptides by translation in a cell-free system. When the resulting total translation products were immunoprecipitated with the rabbit anti-mouse amelogenin antibody, we observed multiple polypeptides, suggesting that the utilization of alternative start sites may also contribute to the observed complexity of amelogenin proteins, at least for artificial mRNAs translated in vitro.
Enamel Crystal Shape: History of an Idea
Authors: Warshawsky H.
Published: January 2017

The purpose of this paper is to review evidence which casts doubt on the interpretation universally applied to hexagonal images seen in sectioned enamel. The evidence is based on two possible models to explain the hexagonal profiles seen in mammalian enamel with transmission electron microscopy. The "hexagonal ribbon" model proposes that hexagonal profiles are true cross-sections of elongated hexagonal ribbons. The "rectangular ribbon" model proposes that hexagonal profiles are caused by three-dimensional segments that are parallelepipeds contained in the Epon section. Since shadow projections of such rectangular segments give angles that are inconsistent with the hexagonal unit cell, a model based on ribbons with rhomboidal cut ends and angles of 60 and 120° is proposed. The "rhomboidal ribbon" model projects shadows with angles that are predicted by the unit cell. It is suggested that segments of such crystallites in section project as opaque hexagons on the imaging plane in routine transmission electron microscopy. Morphological observations on crystallites in sections - together with predictions from the hexagonal, rectangular, and rhomboidal ribbon models - indicate that crystallites in rat incisor enamel are flat ribbons with rhomboidal cross-sectional shape. Hexagonal images in electron micrographs of thin-sectioned enamel can result from rhomboidal-ended, parallelepiped-shaped segments of these crystallites projected and viewed as two-dimensional shadows.
Effect of Colchicine On Iron Transport During Stages of Maturation and Enamel Pigmentation in Rat Incisor Enamel: an Autoradiographic Study Using 55Fe
Authors: Kubota M. , Ohya K. , Ogura H.
Published: January 2017

An autoradiographic study on rats was carried out with 55Fe and colchicine in order to investigate the Arole of microtubules in the iron transport process from rat incisor ameloblasts to the enamel surface. In the control rats injected with 55Fe, autoradiographic silver grains were distributed over the ameloblasts during the whole stage of enamel maturation and over the enamel surface at the enamel pigmentation stage. After the colchicine injection, the area of ameloblasts with smooth distal cell membranes increased in the maturation stage. These ameloblasts were heavily injured, and the iron-containing pigment was released from the cell. The number of silver grains decreased in these ameloblasts. However, the silver grains increased in the area of ameloblasts with ruffled distal cell membranes. At the enamel pigmentation stage, the silver grains over the ameloblasts increased, and those over the enamel surface were reduced. The accumulation and dislocation of the iron-containing pigment was noted in the ameloblasts at this stage. Lumicolchicine injection did not affect the grain distribution. These findings suggest that microtubules regulate the transport and secretion process of iron in rat incisor ameloblasts.
Temperature-Related Ultrastructural Changes in Early Stage Amelogenesis in Vascularly Perfused Rat Incisors
Authors: Takano Y. , Akai M. , Matsuo S. , Wakisaka S. , Ichikawa H. , Nishikawa S.
Published: January 2017

Vascularly perfused rat incisors were investigated by electron microscopy in order to achieve further definition of the origin and nature of stippled material in developing enamel. A prolonged (20-minute) pre-wash perfusion of the rat with a physiological solution at 37°C prior to perfusion fixation retained good morphology of the secretory ameloblasts and adjacent enamel, showing virtually no extracellular accumulation of granular material. Granular material appeared throughout the developing enamel after pre-wash perfusion at low temperatures (0-2°C), and accumulated in the extensively dilated extracellular spaces between the proximal portions of Tomes' processes, where numerous coated pits and coated vesicles were located. Vascular perfusion at 37°C, preceded by a cold perfusion, abolished the granular material in the developing enamel, whereas the granular material in the extracellular spaces between Tomes' processes remained as huge droplets of dense material.

These results indicate that at least a part of the matrix protein of rat incisor developing enamel has the physico-chemical property to dissociate at low temperature during pre-wash perfusion and move toward the enamel surface. Thus, in perfusion-fixed specimens, an intimate relationship between the artifactual formation of stippled material and the temperature of the pre-wash perfusate is suggested.
Resins in Restorative Dental Materials: Reactor Response
Authors: Franz G.F.E.
Published: January 2017

The response stresses two remarks of Prof. Braden about the sensitizing agents and the importance of a decrease of shrinkage in new dental resins.

The objective of our own investigation was to measure the wear of veneering resins brushed with dentifrices and to find a good combination of resin and fillers, as well as which abrasives in toothpastes make the smallest abrasion on veneering resins. The in vitro method-described in this paper-is based on the results obtained in an in vivo abrasion test with dental students. The in vitro abrasion test instrument has to produce similar results with the six tested dentifrices on polymethylmethacrylate as measured in our in vivo test. Two different series of veneering resins were tested, one with increasing cross-linkage, the other with increasing microfiller. In the series with increasing cross-linkage, the hardness increased and the abrasion values decreased. In the series with increasing microfiller, the hardness also increased; however, the abrasion resistance was not related to the hardness. Two dentifrices caused nearly no abrasion, while three higher-abrasive dentifrices showed an increase of abrasion on the 40% and 60% filler-containing specimens. Thus, the abrasion resistance can be improved with the right relation between microfiller and cross-linkage. A toothbrush with medium stiffness and a dentifrice containing an amorphous silica, i.e., Syloblanc 7/82, should be recommended for appropriate oral hygiene when veneering resins are present.

The objective of our second study was to use a torsion test to investigate the bond strength between metal and resin. The results depend on the cross-head speed used, i.e., the stress results increased with the speed.
Current Developments in Posterior Composite Resins
Authors: Leinfelder K.F.
Published: January 2017

The use of posterior composite resins has grown at a rapid rate. While the original materials were completely inadequate for the restoration of Class I and II cavity preparations, the newer-generation materials are apparently superior. While wear rates of over 100 μm per year were not uncommon, some of the newer composites wear away at the rate of less than 1 μm per month.

A great deal of the improvement in wear resistance can be attributed to an optimization of the filler particle. Specifically, the particle size has been decreased and the filler loading has been increased. In some instances, softer filler particles have been incorporated in order to decrease the hardness differential between the filler and the resin matrix. Other factors which have been considered include chemical erosion of the matrix, degradation of the silane coupling agent, internal porosity, method of polymerization, and hydrophobicity of the resin matrix.

A greater understanding has been developed regarding patterns of wear as well as rates of wear. Techniques have been developed for rapid and routine measurements of the loss of anatomical form. Although the composite resins have been improved substantially, their use in posterior teeth is quite technique-sensitive. Furthermore, the problem of secondary caries is still a major concern.
Endodontic Materials
Authors: Ørstavik D.
Published: January 2017

Endodontic sealing materials for permanent obturation of root canals are highly variable both in chemistry of setting and in their additives. Conventional materials are based on zinc oxide-eugenol, rosin-chloroform, or synthetic resins. These have been extensively tested for biological and technical properties. Most materials are slightly or moderately cytotoxic, and some - notably paraformaldehyde-containing materials- have been associated with clinical complications such as paresthesia of the mental and/or inferior alveolar nerve. Recently, Ca(OH)2-containing materials have been introduced with claims of improved clinical and biological performance. However, there is little documentation of the alleged benefits of new materials.

The virtual absence of comparative clinical studies on endodontic filling materials appears to be the major obstacle to critical assessment of old materials or to adequate documentation of new formulae. A recently introduced scoring system for the radiographic assessment of apical periodontitis may aid in the future testing of endodontic materials. Results with this scoring system on extensive clinical material indicate that it is possible to discriminate among endodontic materials with small differences in clinical performance.
Dental Cements
Authors: Smith D.C.
Published: January 2017

The manifold uses of dental cements-as (a) luting agents, (b) cavity linings and bases, and (c) restorations for teeth—make them perhaps the most important materials in clinical dentistry. The research of the last 10 years has resulted in four main types, classified by matrix-forming species: (1) phosphate, (2) phenolate, (3) polycarboxylate, and (4) polymethacrylate. The zinc phosphate cements continue to be widely used for luting in an essentially unchanged form. Acidity and oral dissolution remain as problems. The zinc-oxide eugenol cements and their modifications are useful as linings and temporary materials but are susceptible to hydrolytic breakdown. Vanillate cements may be an improvement. Calcium hydroxide-salicylate cements are widely used as cavity linings, especially on exposures, and show improved resistance to acid dissolution. Polycarboxylate cements as both zinc polycarboxylate and glass-ionomer cements show adhesion potential, good physical properties, fluoride release, and, generally, good biological properties. Glass-ionomer cements when correctly manipulated show minimal oral dissolution. Polymethacrylate cements have been used principally for bonding etched cast metal restorations to etched enamel. Recently, adhesive crown-and-bridge cements have been developed. There are no well-established correlations between laboratory measurements of apparently relevant properties and clinical performance. More clinically-based research is needed to facilitate the development of new cements.
Dental Cements: Reactor Response
Authors: Swartz M.L.
Published: January 2017

This paper is in response to Dr. Dennis Smith's paper, which dealt with the current status of dental cements and recommendations with respect to future research needs. Interest in cements and research in this area have mushroomed with the development of polycarboxylate and glass-ionomer cements. Despite this increased research, there still exist significant voids, which can only be elucidated by further concerted research efforts, both laboratory and clinical.

With newer systems -e.g., the polycarboxylate and glass-ionomer cements—properties such as modulus of elasticity, which were of little concern with the phosphate cements, have now assumed clinical relevance. Also, the need persists to develop an in vitro test that reflects the relative resistance of cements to disintegration in the oral cavity.

Finally, greater efforts should be expended by the research community to disseminate new findings to the dental practitioner in order that the patient population may benefit from the latest advances in materials.
The Problems Preventing Progress in Adhesive Restorative Dentistry
Authors: Fusayama T.
Published: January 2017

Recognition of the following facts is essential for progress in adhesive restorative dentistry: (1) The system removing only the infected outer layer of carious dentin by the caries detector and placing the chemically adhesive composite can save teeth maximally without operative pain;

(2) The traditional fear of dentin etching must be eliminated. The chemically adhesive composite placed upon etched dentin without lining secures maximum retentive stability and pulp safety; and

(3) The chemically adhesive posterior composite, if used properly, is far kinder to teeth than is amalgam.
Calcium Phosphate Materials in Restorative Dentistry: a Review
Authors: Legeros R.Z.
Published: January 2017

This report deals with some of the calcium phosphate materials which are currently used in preventive and restorative dentistry and other calcium phosphate materials which have potential for dental and medical applications. Such materials include those which form calcium phosphate in situ (e.g., Bioglass ceramics and calcium phosphate cements) and those originating from natural materials (such as corals and bones).

The reports on the development and current status of the calcium phosphate ceramics and glass ceramics presented here were based on recent reviews and recent evaluations of clinical studies for the period 1975 to 1986 (Table 3) with humans and with animals when reports on human studies were not yet available. Methods of preparation and relevant physico-chemical properties of some of the calcium phosphate materials were based on data reported in the literature and on other studies by the author. New calcium phosphate materials, e.g., calcium phosphate cements, calcium phosphate-coated implants, calcium phosphate/polymer composites, have also been briefly covered in this report.

Based on the information summarized in Tables 1 to 6 and on solicited comments from clinicians and researchers involved with calcium phosphate materials, several areas of basic and clinical research are recommended (Table 7).
Calcium Phosphate Materials: Reactor Response
Authors: Chow L.C.
Published: January 2017

This provides information supplementing the discussions and conclusions given in the paper presented by Dr. R. Z. LeGeros. Some of the advantages and limitations of calcium phosphate materials as bone implants were discussed. Properties and potential applications of a new calcium phosphate setting cement were described.
Endodontic Materials: Reactor Response
Authors: Mjör I.A.
Published: January 2017

This discussion of a review paper on endodontic materials focuses on the need for standardization of this group of materials, including clinical and biological investigations. It was concluded that the search for endodontic materials that are both adhesive to dentin and insoluble must continue. When such materials become available, the defense mechanism of the body would take care of the healing per se. This approach as well as techniques and materials which induce dentin bridge formation in the apical area were considered feasible for improving endodontic treatment. The need to report side-effects of endodontic materials was stressed, and it was suggested that such reports should be mandatory for clinicians and for manufacturers of endodontic materials.
Porcelain Materials: Reactor Response
Authors: Fairhurst C.W.
Published: January 2017

Dr. Moffa's suggestion of removing internal surface flaws in porcelain restorations is discussed in terms of ceramic fatigue mechanisms. His suggestions for development of a universal shade of porcelain are discussed. Dr. Moffa suggests that better clinical studies are needed for determining effectiveness of porcelain restorations.
Chemotaxis of Cells Isolated from Periodontal Tissues to Different Biological Response Modifiers
Authors: Terranova V.P. , Wikesjo U.M.E.
Published: January 2017

Directed migration of many different cell types is necessary for uneventful wound healing to occur. From clinical periodontal regeneration procedures, it is commonly believed that periodontal ligament cells will be of critical importance in obtaining a new connective tissue attachment. Here we present data which indicate that extracellular matrix components (fibronectin) and polypeptide growth factors (FGF, TGF-a, and TGF-β) modulate the ability of periodontal ligament cells to express directed migration. These data indicate a potential role for matrix components and growth factors in clinical periodontal regenerative procedures.
Collagen Remodeling in Wound Healing by Gingival Fibroblasts in Vitro
Authors: Yajima T.
Published: January 2017

Collagen degradation by fibroblasts was studied in the absence of other cell types to improve our understanding of the mechanisms by which fibroblasts digest collagen. Human gingival fibroblasts were cultured in α -MEM medium for eight weeks. Incisional wounds were made in the fibroblast cultures, and the cells were fixed by different procedures at two days post-wounding. Collagen remodeling has been investigated by tracer experiments and by cytochemical demonstration of acid and alkaline phosphatase activity at the ultrastructural level and stereological analysis in experimental wound-healing in vitro.

The results showed that fibroblasts in the wounded zone exhibited high collagen phagocytic activity, and indicate that fibroblasts have a fundamental role to play in collagen remodeling in wound repair in vitro. This in vitro experimental system is also suggested as a useful model for the analysis of collagen remodeling in wound-healing by fibroblasts.
Actinobacillus Actinomycetemcomitans in the Pathogenesis of Human Periodontal Disease
Authors: Zambon J.J. , Umemoto T. , De Nardin E. , Nakazawa F. , Christersson L.A. , Genco R.J.
Published: January 2017

The present report reviews data implicating Actinobacillus actinomycetemcomitans in the etiology of human periodontal disease. Recent data are also presented relative to: (1) serological studies of this microorganism using monoclonal antibodies and the serodiagnosis of A. actinomycetemcomitans infections; (2) characterization of the serotype antigens; (3) studies of the serotype distribution of A. actinomycetemcomitans in extra-oral infections; and (4) examination of the correlation between A. actinomycetemcomitans colony morphology and fimbriae.
The Role of Spirochetes in Periodontal Disease
Authors: Loesche W.J.
Published: January 2017

The spirochetal accumulation in subgingival plaque appears to be a function of the clinical severity of periodontal disease. It is not known how many different spirochetal species colonize the plaque, but based upon size alone, there are small, intermediate-sized, and large spirochetes. Four species of small spirochetes are cultivable, and of these, T. denticola has been shown to possess proteolytic and keratinolytic enzymes as well as factors or mechanisms which suppress lymphocyte blastogenesis and inhibit fibroblast and polymorphonuclear leukocyte (PMNL) function. All of these attributes could contribute to periodontal tissue insult. Yet independent of these potential virulence mechanisms, the overgrowth of spirochetes can be clinically useful if simply interpreted as indicating the result of tissue damage. In this case, the spirochetes would be indicators of disease and could be easily monitored by microscopic examination of plaque, or possibly by the measurement of benzoyl-DL-arginine-2-naphthylamide (BANA) hydrolytic activity in the plaque.
Characterization and Immunobiologic Activities of Lipopolysaccharides From Periodontal Bacteria
Authors: Hamada S. , Koga T. , Nishihara T. , Fujiwara T. , Okahashi N.
Published: January 2017

Bacterial surface structures play a critical role in the initiation of infectious diseases. Various surface components of pathogenic bacteria have been reported to be involved in host injury. There is a great deal of evidence incriminating certain Gram-negative, anaerobic bacteria present in the gingival crevice as etiologic agents of human periodontal diseases. We have isolated endotoxic cellular components from suspected periodontopathic bacteria and examined their immunobiological activities. Lipopolysaccharides (LPS) and lipid-associated proteoglycans (LPG) were prepared from whole cells by the phenol-water and butanol-water procedures, respectively. LPS from Bacteroides gingivalis, B. intermedius, B. oralis, and B. loescheii, Fusobacterium nucleatum and F. necrophorum, and Actinobacillus (Haemophilus) actinomycetemcomitans were found to possess biological activities comparable with those of LPS from E. coli K235 in terms of activation of Limulus lysate, B-cell mitogenicity, polyclonal B-cell activation, induction of bone resorption, and IL-1 production by macrophages. These LPS contained mainly sugars, amino sugars, and fatty acids. No heptose or 2-keto-3-deoxyoctonate (KDO) was detected in the Bacteroides LPS, while LPS from Actinobacillus and Fusobacterium species contained significant amounts of heptose as well as small quantities of KDO. Bacteroides LPS were clearly mitogenic for spleen cells of C3H/HeJ mice, which are non-responsive to LPS from E. coli, A. actinomycetemcomitans, and Fusobacterium species. Furthermore, polymyxin B was found to abrogate the mitogenic activity of LPS from E. coli, Actinobacillus, and Fusobacterium species, but not those from Bacteroides species. Spleen cells from both C3H/HeN and C3H/HeJ mice responded to all butanol-water-extracted LPG preparations, including those from E. coli, A. actinomycetemcomitans, and Fusobacterium species. It may be concluded that LPS and LPG isolated from suspected periodontopathic bacteria possess marked immunobiological potencies on lymphoreticular and bone cells.
Proteolytic Activities of Mycoplasma Salivarium
Authors: Watanabe T.
Published: January 2017

Proteolytic activity was demonstrated in ATCC 23064 and oral isolates (more than 100 strains) of My coplasma salivarium and was suggested to be due to aminopeptidase, some other metalloproteinases, and serine proteinases. An aminopeptidase and a carboxypeptidase were purified from cell membranes of the organism and characterized. In amino acid specificities, the aminopeptidase was different from aminopeptidase B and leucine aminopeptidase, and the carboxypeptidase from carboxypeptidases B and N. These enzymes are considered to play a role in providing the organism with arginine as a main energy source, eventually facilitating the production of ammonia, and in protecting the organism and the other co-existing pathogens from defense mechanisms of the host by inactivating kallidin, bradykinin, tuftsin, and anaphylatoxins such as C3a and C5a.
Gene Cloning and Expression of a Bacteroides Gingivalis-Specific Protein Antigen in Escherichia Coli
Authors: Abiko Y. , Hayakawa M. , Aoki H. , Takiguchi H.
Published: January 2017

Gene banks of chromosomal DNA from Bacteroides gingival is 381 were constructed utilizing the bacteriophage replacement vector λCharon4A. A clone encoding a protein antigen from B. gingivalis was identified by Western-blot screening, with use of antiserum induced to extracts of B. gingivalis cells. DNA fragments from the phage clone were subcloned into the plasmid vector pACYC184 to yield an immunoreactive clone. Cell extracts from the subclone reacted with antiserum against B. gingivalis, but did not react with antisera to B. asaccharolyticus, B. intermedius, or B. melaninogenicus. The antiserum against the purified clone products reacted with N-lauryl sarcosine extracts from B. gingivalis cells, but did not react with those of other Bacteroides cells. In addition, human serum from periodontitis patients reacted with the clone product by Western electrophoretic transfer and immunoblotting analysis. These data suggest that the gene coding for a B. gingivalis-specific protein antigen was successfully cloned and functionally expressed in Escherichia coli. This clone product may prove useful for further studies of B. gingival is as a periodontal pathogen.
Cross-Reactive Monoclonal Antibodies Induced by Lps from Periodontopathic Bacteria
Authors: Kato T. , Okuda K. , Takazoe I.
Published: January 2017

Monoclonal antibodies against lipopolysaccharides (LPS) of Fusobacterium nucleatum ATCC 25586 and Eikenella corrodens FDC 1073 were used for the study of antigenic characteristics of periodontopathic bacteria.

LPS was extracted by the hot-phenol/water method. Three monoclonal antibodies (isotype IgM) against F. nucleatum ATCC 25586 were cross-reactive with LPS from E. corrodens FDC 1073. Four hybridomas producing antibody to E. corrodens FDC 1073 LPS were also obtained. Three out of four monoclonal antibodies (isotype IgM) were found to exhibit cross-reactivity with LPS from F. nucleatum ATCC 25586. These six monoclonal antibodies reacted with four out of seven E. corrodes and nine out of 27 F. nucleatum clinical isolates. Western immunoblotting analysis demonstrated that the six antibodies reacted with a similar fast-migrating band of LPS from F. nucleatum ATCC 25586 and E. corrodens FDC 1073. Another monoclonal antibody (isotype IgG3) against E. corrodens FDC 1073 LPS exhibited cross-reactivity with LPS from Fusobacterium necrophorum ATCC 25286 and Capnocytophaga ochracea M-12. This antibody was found to react with slow-migrating bands of E. corrodens FDC 1073 LPS and a fast-migrating band of LPS from F. necrophorum ATCC 25286 and C. ochracea M-12 by Western immunoblotting analysis. Four out of seven clinical isolates of E. corrodens reacted strongly with this antibody.

The present findings indicate that there is a common LPS core epitope between F. nucleatum ATCC 25586 and E. corrodens FDC 1073. They also indicated that the O-side-chain epitope of E. corrodens FDC 1073 might be common to the LPS core epitopes of F. necrophorum ATCC 25286 and C. ochracea M-12.
Immunoregulatory Aspects of Periodontal Disease
Authors: Taubman M.A. , Stoufi E.D. , Seymour G.J. , Smith D.J. , Ebersole J.L.
Published: January 2017

This manuscript reviews our studies of the composition and functional capabilities of gingival tissue lymphocytes from patients with periodontal disease. The emphasis has been on phenotyping the local lymphoid infiltration in gingival and periodontal disease. The preparation and phenotypic analyses of cells recovered from diseased and healthy human periodontal tissues indicated that T-cell subset ratios from diseased tissue were significantly decreased compared with peripheral blood or normal tissue ratios. These reductions were verified in a second study we performed using two-color immunofluorescence analyzed by flow cytofluorometry. Local variations in the CD4 + cell population were also found in diseased tissue cells when these were compared with normal tissue cells. The relative percentage of CD4+ cells labeled with anti-helper inducer (4B4) or anti-suppressor inducer (2H4) monoclonal antibodies was increased above that of normal tissue cells. Functional studies of immunoglobulin production by gingival cells from adult periodontitis tissues showed two discrete patterns of synthesis and also suppression of immunoglobulin synthesis after addition of mitogen to the cultures. Removal of macrophages also drastically reduced immunoglobulin synthesis by gingival cells. These results indicate that there is an abundance of suppressor T-cells in diseased tissue and that functional suppression is demonstrated by lymphocytes from periodontal disease tissue. The findings of these investigations have suggested potentially important roles for immune regulation in periodontal disease.
Serum Immunoglobulin G Antibody To Periodontal Bacteria
Authors: Murayama Y. , Nagai A. , Okamura K. , Kurihara H. , Nomura Y. , Kokeguchi S. , Kato K.
Published: January 2017

The purpose of this study was to assess the serum antibody levels to periodontal bacteria in patients with periodontal disease, and to explore the diagnostic uses of the serum antibody assessment and its potential as a therapeutic guide.

One hundred twenty-nine patients were clinically examined for the type and extent of periodontal destruction and serum IgG antibody levels to Actinobacillus actinomycetemcomitans (Aa), Actinomyces israelii (Ai), A. viscosus (Av), Bacteroides asaccharolyticus (Ba), B. corporis (Bc), B. denticola (Bd), B. gingivalis (Bg), B. intermedius (Bi), B. loescheii (BI), Capnocytophaga gingivalis (Cg), C. ochracea (Co), and Fusobacterium nucleatum (Fn). Clinical and serological data were subjected to correlation analyses. A small group of patients was monitored during the progress of periodontal treatments.

The IgG antibody levels were assessed with an enzyme-linked immunosorbent assay (ELISA).

Significantly elevated IgG antibody levels were manifested to Aa, Ai, Bg, and Fn in all forms of periodontal disease, additionally to Cg and Co in juvenile periodontitis, and to Bi in adult periodontitis. There were some correlations between a few clinical parameters and the antibody levels. Successful periodontal treatment significantly decreased the antibody levels to all of the micro-organisms; however, during periodontal treatment, there were no marked differences between pre- and post-treatment levels.

The antibody reactivities to the periodontopathic micro-organisms may be of diagnostic and predictive value in patients.
Variable Sensitivity of Oral Isolates of Eikenella Corrodens to Serum Bactericidal Activity: Role of Antibody
Authors: Chen C. , Wilson M.E.
Published: January 2017

Eikenella corrodens is a facultatively anaerobic Gram-negative bacterium which is among the predominant cultivable microflora of periodontal lesions characterized by loss of attachment level. In the present study, we examined the potential role of complement-mediated killing in host defense against this periodontopathic organism. Seven clinical isolates obtained from human subgingival plaque and one reference strain of E. corrodens were characterized with respect to (a) susceptibility to the bactericidal properties of pooled human serum and (b) the role of the classical and/or alternative pathway(s) of complement in effecting killing of sensitive strains. Six strains, including the reference strain, were found to be variably serum-sensitive, exhibiting 1-12.5% survival after two hr of incubation in the presence of 20% pooled human serum. The remaining two isolates were serum-resistant. Both serum-resistant and serum-sensitive strains consumed complement via the classical pathway in normal but not in hypogammaglobulinemic serum, thus ruling out an antibody-independent mechanism of classical pathway activation. Four of six serum-sensitive strains exhibited little or no loss of viability following incubation with serum depleted of the classical pathway component Clq. One strain which was resistant to killing by normal human serum was, nevertheless, highly susceptible to complement-mediated killing in the presence of rabbit immune serum. Two additional serum-sensitive strains were killed, albeit to a lesser extent, in Clq-depleted serum, indicative of a role of the alternative pathway in killing of some serum-sensitive strains. These results indicate a potential role for complement-mediated killing in host defense against Gram-negative periodontal bacteria such as E. corrodens. However, the ultimate contribution of this immune defense mechanism may be defined, at least in part, by the presence of a humoral response to key bacterial membrane constituents.
Neutrophil Defects and Host-Parasite Interactions in the Pathogenesis of Localized Juvenile Periodontitis
Authors: Van Dyke T.E. , Offenbacher S. , Kalmar J. , Arnold R.R.
Published: January 2017

Through the study of host responses in periodontal diseases, the role of the neutrophil as an important protective cell in the pathogenesis of disease has become apparent. In this report, we examine the neutrophil defects associated with localized juvenile periodontitis to include defects of cell surface protein expression, defects of signal transduction, and defects of bactericidal activity. We report that LJP neutrophils are deficient in chemotactic factor receptors and a chemotaxis-related glycoprotein (GP110). There is a deficit of signal transduction, resulting in a decrease in leukotriene B4 production, and the LJP neutrophil is deficient in its ability to kill the periodontal pathogen, Actinobacillus actinomycetemcomitans. The study of neutrophil biology in the LJP model and the application of these studies to the more prevalent disease, adult periodontitis, are discussed.
Monitoring of Subgingival Bacteroides Gingivalis and Actinobacillus Actinomycetemcomitans in the Management of Advanced Periodontitis
Authors: Christersson L.A. , Rosling B.G. , Dunford R.G. , Wikesjö U.M.E. , Zambon J.J. , Genco R.J.
Published: January 2017

In a series of clinical trials involving 79 adult periodontitis patients, we evaluated the clinical and microbiological effects of H2O2, NaHCO3, and a commercially available povidine solution, as adjuncts to mechanical periodontal debridement. Each trial included a placebo as a control. The healing response was monitored clinically by measurement of changes in probing attachment levels after treatment. The current report includes data from single-rooted teeth only.

In general, healing in severely advanced periodontal lesions (initial pocket depth ≥ 7 mm) was enhanced by the use of the listed topical antimicrobial agents administered subgingivally during mechanical debridement.

Correlations were sought between changes in probing attachment levels 12 months after treatment, and the presence of subgingival B. gingivalis and A. actinomycetemcomitans in the periodontal lesions. For a total of 428 lesions included in this report, B. gingivalis was detected in 53.1% of lesions showing probing attachment loss (≥1.5 mm), but in only 4.7% of lesions showing gain (≥ 1.5 mm). Either B. gingivalis or A. actinomycetemcomitans was detected in 70.1% of the lesions showing loss and in only 4.8% of those showing gain. These studies indicate the benefits of the adjunctive antimicrobial therapy described, and the usefulness of specific microbiological monitoring as an aid to clinical measurements in the evaluation of success or failure of treatment of chronic adult periodontitis.
Review of Terminology, Classifications, and Indices of Developmental Defects of Enamel
Authors: Clarkson J.
Published: January 2017

A wide variety of terms and definitions are used to describe various developmental defects of enamel. Some are simple descriptive clinical terms, and others are linked with the causative agent or the histopathology of the defect. Some confusion exists as to the most appropriate type of index to use to measure defects of enamel due to fluoride ingestion (dental fluorosis). This is primarily due to difficulties some researchers have in distinguishing between defects of fluoride and non-fluoride origin. This problem has resulted in the development of specific fluorosis indices and purely descriptive indices. The main fluorosis indices are those of Dean, Thylstrup and Fejerskov, and the TSIF Index. Dean's Index does not provide adequate information on the distribution of fluorosis within the dentition and is not sensitive at high fluorosis levels. The Thylstrup and Fejerskov Index is related to the histology of fluorosis; however, the initial minute changes observed on dry enamel surfaces are of little esthetic importance. The TSIF Index does overcome some of the limitations of Dean's Index. The DDE Index has replaced the Al-Alousi Index as the main descriptive index. The DDE Index is time-consuming, and the analyses of data are complicated. Modifications have now been proposed to make it simpler to use and the data more meaningful. Further research needs to be carried out into both the validity of the fluorosis indices and making the DDE Index more universally acceptable.
The Prevalence of Developmental Defects of Tooth Enamel (DDE) in a Pediatric Hospital Department of Dentistry Population (Part I)
Authors: Hall R.K.
Published: January 2017

This paper reports the first part of a three-part study of developmental defects of tooth enamel in a pediatric hospital population. The dental records of 8411 children who were discharged from the Department of Dentistry at the Royal Children's Hospital, Melbourne, Australia, between 1960 and 1987 were divided into an experimental group of 7518 patients comprising 25 groups of medical conditions, and a control group of 893 children who had dental disorders only. The aim of the study was to investigate the prevalence of hypoplastic and severe-opacity developmental defects of tooth enamel (DDE), in children and adolescents with major medical disorders, and to compare the prevalence with that in the control group of normal children. The prevalence figures obtained for the different medical conditions in this study agreed generally with those of other recent investigators. The high prevalence of defects found in Rubella Embryopathy children (81.8%) and in children with Prematurity alone (56.5%) is surprising, whereas the prevalence of 27.9% defects in Clefts of Lip and Palate and 26.4% defects in Clefts of Lip and Alveolus are probably well below the true prevalence. The control group prevalence was 9.3%, which is higher than in some other studies of 'normal' children. A pediatric hospital is a most useful source of fully documented medical and dental histories for the investigation of possible relationships between medical disorders and developmental defects of tooth enamel.
Hypocalcification and Hypoplasia in Permanent Teeth of Children From Different Ethnic Groups in South Africa Assessed With a New Index
Authors: Hargreaves J.A. , Cleaton-Jones P.E. , Williams S.D.L.
Published: January 2017

A new descriptive index, the HHI (hypocalcification-hypoplasia index), is described for comparing enamel defects in groups of people. The index was used in a study completed in 1986, in which 1251 11-year-old children from different ethnic groups resident in South Africa were examined: 210 rural black, 203 urban black, 206 urban colored, 426 urban Indian, and 206 urban white. The index can be used as a screening examination, and the results from these different ethnic groups are presented.
Enamel Fluoride in Relation To Severity of Human Dental Fluorosis
Authors: Richards A. , Fejerskov O. , Baelum V.
Published: January 2017

The aim of this study was to test whether the concentrations of fluoride in fluorotic human enamel are related to the degree of severity of dental fluorosis classified according to the index described by Thylstrup and Fejerskov. Teeth representing the entire spectrum of human dental fluorosis were analyzed. Fluoride concentrations were determined by serial acid-etching from surface to interior of blocks of enamel cut from each tooth. Fluoride was measured by ion electrode and calcium by atomic absorption spectrophotometry. The results showed that the pattern of distribution of fluoride in fluorotic enamel is similar to that described for normal enamel. Increasing severity of fluorotic lesions was associated with increasing concentrations of fluoride throughout the enamel. It is concluded that although further studies are required to establish the relative contribution of fluoride which may be taken up posteruptively by fluorotic enamel, the findings support the hypothesis that the TF index reflects increasing exposure to fluoride during tooth development.
Relationship of Dental Caries and Fluorosis to Fluoride Supplement History in a Non-Fluoridated Sample of Schoolchildren
Authors: Bagramian R.A. , Narendran S. , Ward M.
Published: January 2017

A random sample of 206 Michigan children, aged from 9 to 13, were examined for fluorosis from a larger group of 2038 children participating in a dental project. Clinical examinations included caries data (DMFS) and assessment of fluorosis by use of the Tooth Surface Index of Fluorosis (TSIF). Separate examiners were used for each index. The response rate of a questionnaire mailed to parents to gather information on residence histories, use of fluoride supplements, and antibiotics was 78%. The prevalence of fluorosis was about 20% among the respondents. Of the 4868 tooth surfaces examined, 9.2% were affected by fluorosis. In all cases, dental fluorosis was judged as mild, with most occurrences on the posterior teeth. No instances of moderate or severe fluorosis were found. The caries experience of respondents was 1.69 ± 2.73 DMFS. Caries experience does not appear to be significantly related to income, education, or fluoride supplement use. Approximately 52% of respondents were reported to have taken fluoride supplements with various degrees of consistency. Parents' education was positively related to both prevalence of fluorosis (odds ratio = 2.2) and use of fluoride supplements (odds ratio = 2.7). No significant relation was revealed with evidence of fluorosis and use of supplements. This study shows a relatively mild level of dental fluorosis in a sample of children from a non-fluoridated area. Dental fluorosis in this group does not appear to be related to use of fluoride supplements or differences in caries experience.
Effect of Prenatal and Postnatal Fluoride on the Human Deciduous Dentition. A Literature Review
Authors: Gedalia I. , Shapira L.
Published: January 2017

Fluoride passes from the mother to fetal teeth. Much of the fluoride is taken up in secretory enamel, probably by the forming mineral apatite crystals. Some is retained with residual proteins. The low concentration of fluoride in the inner enamel is incorporated mainly during the secretory stage, while the enhanced concentration in the surface enamel is produced during the much longer maturation stage. Mature, hard enamel is generally absent during fetal life. The clinical question is whether prenatal fluoride imparts an additional benefit to the universally accepted effect of postnatal fluoride. In general, surface enamel fluoride levels of deciduous teeth increase with increasing pre- and postnatal fluoride administration. A consistent level of caries protection has been reported with pre- and postnatal administration of fluoride unrelated to the acquisition of fluoride in the surface enamel.

Many children develop enamel opacities in their deciduous dentition related by various factors to enamel mineralization disturbances in drinking water areas even low in fluoride. Accumulation of fluoride due to an increased fluoride intake is a feature of fluorosed enamel in the deciduous as well as permanent dentition. The resulting mature fluorosed enamel retains a relatively high proportion of immature matrix proteins onto the crystal surface. The degree of fluorosis of the deciduous dentition is less compared with that of the permanent dentition, due probably to a partial protection afforded by the maternal loss of fluoride, formerly known as the "placental barrier".
Use of Fluoride by Young Children and Prevalence of Mottled Enamel
Authors: Woltgens J.H.M. , Etty E.J. , Nieuwland W.M.D. , Lyaruu D.M.
Published: January 2017

The prevalence of mottled enamel in the permanent dentition of children participating in a fluoride (F-) program at the dental school of the Vrije Universiteit (Amsterdam) was investigated in a study utilizing the Thylstrup-Fejerskov (TF) index. The randomly chosen children received a F- regime considered optimal by the Dutch Advisory Committee for Prevention of Oral and Dental Diseases. From the children examined (n = 83; 49 boys and 34 girls; mean age, 13 years and 5 months), 74% exhibited mottled enamel in a slight to moderate degree. More teeth were affected and the degree of mottling was higher when children started to use F- at an earlier age. Unintentional ingestion of toothpaste containing 0.15% F- during frequent toothbrushing in combination with the daily intake of F- tablets before the age of four may explain the high prevalence of mottled enamel. After these treatments, F- concentrations in plasma of young children can reach values which can directly affect the developing tooth germ.