PubMed Journal Database | Journal of dental research

Degradation of 10-Methacryloyloxydecyl Dihydrogen Phosphate.

To understand the mechanism of 10-methacryloyloxydecyl dihydrogen phosphate (MDP) hydrolysis, we investigated the degradation of 2-methacryloyloxyethyl dihydrogen phosphate (MEP), because the MEP molecule has the methacryloxy and phosphate ester portions of MDP but, unlike the latter, is water-soluble. The MEP-N-methcryloyl glycine (NMGly), MDP-NMGly, and MDP-2-hydroxyethyl methacrylate (HEMA) primers were designed, stored for different periods, and then analyzed. Our null hypotheses were that (1) the mecha...

Defining the Contribution of Genetics in the Etiology of Dental Caries.

Measuring the Color of Maxillofacial Prosthetic Material.

Color information from different color-measuring systems varies during color matching in maxillofacial prosthetics. We studied the hypothesis that a non-contact measuring system and 4 contact color-measuring instruments perform comparably in accuracy and precision on measurements of pigmented maxillofacial elastomer specimens having human skin colors. Measurement comparisons in accuracy on opaque standard color patches were made in Phase I. In Phase II, the system with the best accuracy was used as the refe...

Effect of Glass-ionomer Cement on the Progression of Proximal Caries.

Although effective preventive strategies exist for pit and fissure caries, prevention of proximal caries remains a significant challenge. This split-mouth study was designed to investigate the effect of glass-ionomer cement (GIC) on the progression of initial proximal caries in posterior teeth, testing the hypothesis that local application of fluoride-releasing GIC would reduce this progression. GIC was applied to 41 pairs of posterior teeth after elastic band separation in 7- to 19-year-old individuals. Fo...

Taste Genes Associated with Dental Caries.

Dental caries is influenced by a complex interplay of genetic and environmental factors, including dietary habits. Previous reports have characterized the influence of genetic variation on taste preferences and dietary habits. We therefore hypothesized that genetic variation in taste pathway genes (TAS2R38, TAS1R2, GNAT3) may be associated with dental caries risk and/or protection. Families were recruited by the Center for Oral Health Research in Appalachia (COHRA) for collection of biological samples, demo...

Tea Catechin EGCg Suppresses the mgl Gene Associated with Halitosis.

Epigallocatechin gallate (EGCg), the main antimicrobial tea catechin, has been reported to inhibit growth and virulence factors of oral pathogens in vitro. Although the mechanism is unclear, the potential of EGCg in reducing halitosis caused by volatile sulfur compounds (VSCs) has been suggested. This study tested the hypothesis that EGCg reduces VSCs by suppressing mgl, the gene encoding L-methionine-α-deamino-γ-mercaptomethanelyase, responsible for methyl mercaptan (CH(3)SH) production by oral anaerobes...

Application of Polychromatic {micro}CT for Mineral Density Determination.

Accurate assessment of mineral density (MD) provides information critical to the understanding of mineralization processes of calcified tissues, including bones and teeth. High-resolution three-dimensional assessment of the MD of teeth has been demonstrated by relatively inaccessible synchrotron radiation microcomputed tomography (SRμCT). While conventional desktop μCT (CμCT) technology is widely available, polychromatic source and cone-shaped beam geometry confound MD assessment. Recently, considerable...

Diet and Caries-associated Bacteria in Severe Early Childhood Caries.

Frequent consumption of cariogenic foods and bacterial infection are risk factors for early childhood caries (ECC). This study hypothesized that a short diet survey focused on frequency of foods, categorized by putative cariogenicity, would differentiate severe ECC (S-ECC) from caries-free children. Children's diets were obtained by survey and plaque bacteria detected by PCR from 72 S-ECC and 38 caries-free children. S-ECC children had higher scores for between-meal juice (p < 0.01), solid-retentive foods (...

The Long-term Effects of Water Fluoridation on the Human Skeleton.

Municipal water fluoridation has notably reduced the incidence of dental caries and is widely considered a public health success. However, ingested fluoride is sequestered into bone, as well as teeth, and data on the long-term effect of exposure to these very low doses of fluoride remain inconclusive. Epidemiological studies suggest that effects of fluoride on bone are minimal. We hypothesized that the direct measurement of bone tissue from individuals residing in municipalities with and without fluoridated...

Accuracy of NHANES Periodontal Examination Protocols.

This study evaluates the accuracy of periodontitis prevalence determined by the National Health and Nutrition Examination Survey (NHANES) partial-mouth periodontal examination protocols. True periodontitis prevalence was determined in a new convenience sample of 454 adults ≥ 35 years old, by a full-mouth "gold standard" periodontal examination. This actual prevalence was compared with prevalence resulting from analysis of the data according to the protocols of NHANES III and NHANES 2001-2004, respectively...

Does Incomplete Caries Removal Reduce Strength of Restored Teeth?

Little information is available about whether the presence of residual caries beneath an occlusal restoration affects fracture strength of the tooth. This in vitro study tested the hypothesis that restored teeth after incomplete excavation have lower fracture strengths than restored teeth after complete excavation. Fourteen pairs of molars were randomly assigned to an experimental (incomplete excavation) or to a control group (complete excavation) and loaded vertically (after cyclic loading). Failure load a...

Osteogenic Potential of Mandibular vs. Long-bone Marrow Stromal Cells.

Although fundamentally similar to other bones, the jaws demonstrate discrete responses to developmental, mechanical, and homeostatic regulatory signals. Here, we hypothesized that rat mandible . long-bone marrow-derived cells possess different osteogenic potential. We established a protocol for rat mandible and long-bone marrow stromal cell (BMSC) isolation and culture. Mandible BMSC cultures formed more colonies, suggesting an increased CFU-F population. Both mandible and long-bone BMSCs differentiated int...

HEMA Enhances IgG1 Production by Human B-Cells in vitro.

We have previously shown that the resin monomer 2-hydroxyethylmethacrylate (HEMA) affects mouse B-lymphocyte activity, leading to increased IgG1 antibody production . In the present study, we tested, , the hypothesis that HEMA also affects human B-lymphocyte activity. The production of IgG1, IgM, and IgA in supernatants from purified human CD19+ B-lymphocyte cultures, containing different concentrations of HEMA, was assayed with ELISA. Proliferation was measured by [methyl-H] thymidine incorporation. Of the...

Effects of Respiration on Soft Palate Movement in Feeding.

Cyclic soft palate elevation is temporally associated with masticatory jaw movement. However, the soft palate is normally lowered during nasal breathing to maintain retropalatal airway patency. We tested the hypothesis that the frequency and amplitude of soft palate elevation associated with mastication would be reduced during inspiration. Movements of radiopaque soft palate markers were recorded by videofluorography while 11 healthy volunteers ate solid foods. Breathing was monitored with plethysmography....

What Psychosocial Factors Influence Adolescents' Oral Health?

Few studies have examined, comprehensively and prospectively, determinants of oral-health-related quality of life. The aim of this study was to examine the relationships between psychosocial factors and oral health status, health perceptions, and quality of life. Measures of symptom and functional status, health perceptions, quality of life, oral health beliefs, and psychological (sense of coherence, self-esteem, health locus of control) and social factors (parents' income and education) were collected from...

Assessing Tooth Color Differences in Digital Facial Portraits.

Although a large body of scientific literature shows that background color and luminance affect color perception, previous measurements of tooth color difference thresholds have not taken the effects of viewing context into account. The present study tested the hypothesis that differences in skin/gingival color influence individuals' judgments of tooth color differences. Perceptibility and acceptability thresholds were determined in 10 individuals using a signal detection paradigm. They evaluated 500 pseudo...

Randomized Clinical Trial of Treatment for TMJ Disc Displacement.

Of the various conservative treatment modalities available for temporomandibular disorders, we believe that therapeutic exercise has a good prognosis, especially for anterior disc displacement without reduction. Since its effectiveness has not been extensively evaluated, we conducted a comparative study to verify the hypothesis that treatment efficacy would not differ for exercise and occlusal splints. Fifty-two individuals with anterior disc displacement without reduction were randomly assigned to a splint...

The rgg Gene is a Specific Marker for Streptococcus Oralis.

Although the pathogenesis of may be different from that of other viridans group streptococci, shares a high degree of DNA sequence similarity with these streptococci. As a result, discrimination of from its close relatives has long been considered difficult. This study was conducted to find specific genes that allow for the identification of , but not other oral commensals. Four hundred ninety clones obtained by suppressive subtractive hybridization were used for Southern hybridization, and positive clones...

Comparative Human Salivary and Plasma Proteomes.

The protein compositions, or the proteomes, found in human salivary and plasma fluids are compared. From recent experimental work by many laboratories, a catalogue of 2290 proteins found in whole saliva has been compiled. This list of salivary proteins is compared with the 2698 proteins found in plasma. Approximately 27% of the whole-saliva proteins are found in plasma. However, despite this apparent low degree of overlap, the distribution found across Gene Ontological categories, such as molecular function...

The Use of Nanoparticles to Control Oral Biofilm Formation.

Nanoparticles are normally considered to be of a size no greater than 100 nm, and the exploitation of their unique attributes to combat infection has increased markedly over the past decade. The potential of nanoparticles to control the formation of biofilms within the oral cavity, as a function of their biocidal, anti-adhesive, and delivery capabilities, is now coming under close scrutiny. Possible uses as constituents of prosthetic device coatings, as topically applied agents, and within dental materials...

TGF-{beta} Signaling in Gingival Fibroblast-Epithelial Interaction.

The underlying mechanism and the therapeutic regimen for the transition of reversible gingivitis to irreversible periodontitis are unclear. Since transforming growth factor (TGF)-beta has been implicated in differentially regulated gene expression in gingival fibroblasts, we hypothesized that TGF-beta signaling is activated in periodontitis-affected gingiva, along with enhanced collagen degradation, that is reversed by TGF-beta inhibition. A novel three-dimensional (3D) gel-culture system consisting of prim...

Oxidative Stress, Systemic Inflammation, and Severe Periodontitis.

Periodontal infections have been associated with a state of chronic inflammation. To ascertain whether severe periodontitis and its treatment are associated with oxidative stress, we recruited 145 cases (periodontitis) and 56 controls in a case-control study. A further pilot intervention study of 14 cases (periodontal therapy) was performed. Blood samples were taken at baseline (case-control) and 1, 3, 5, 7, and 30 days after treatment (intervention). Diacron-reactive oxygen metabolites (D-ROM), anti-oxidan...

Infiltrants Inhibit Progression of Natural Caries Lesions in vitro.

To define the optimized material properties of caries-infiltrating resins (infiltrants), we evaluated the effects of infiltrant composition and penetration coefficient (PC) on the inhibition of the progression of natural approximal caries lesions . Non-cavitated natural enamel lesions were etched (15% HCl gel) and infiltrated for 5 min with experimental resins varying in PC (cm/sec): PC63, PC185, PC204, and PC391. As a positive control (PosC), lesions were covered with flowable composite resin, whereas untr...

New Approaches to Enhanced Remineralization of Tooth Enamel.

Dental caries is a highly prevalent diet-related disease and is a major public health problem. A goal of modern dentistry is to manage non-cavitated caries lesions non-invasively through remineralization in an attempt to prevent disease progression and improve aesthetics, strength, and function. Remineralization is defined as the process whereby calcium and phosphate ions are supplied from a source external to the tooth to promote ion deposition into crystal voids in demineralized enamel, to produce net min...

Characterization of Progenitor Cells in Pulps of Murine Incisors.

The continuous growth of rodent incisors requires the presence of stem cells capable of generating ameloblasts and odontoblasts. While epithelial stem cells giving rise to ameloblasts have been well-characterized, cells giving rise to the odontoblasts in incisors have not been fully characterized. The goal of this study was to gain insight into the potential population in dental pulps of unerupted and erupted incisors that give rise to odontoblasts. We show that pulps from unerupted incisors contain a signi...