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2. |
- Bryndahl, Fredrik, et al.
(författare)
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Bilateral TMJ Disk Displacement Induces Mandibular Retrognathia
- 2006
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Ingår i: Journal of Dental Research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 85:12, s. 1118-1123
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Tidskriftsartikel (refereegranskat)abstract
- Unilateral non-reducing TMJ disk displacement has been shown to retard mandibular growth on the ipsilateral side, with facial asymmetry a sequela. We hypothesized that bilateral affliction would impair mandibular growth bilaterally, generating mandibular retrognathia. Non-reducing TMJ disk displacement was surgically created in 10 growing New Zealand White rabbits. Ten additional rabbits served as a sham-operated control group. Facial growth was followed in serial cephalograms, with tantalum implants, during a period corresponding to childhood and adolescence in man. The results verified that bilateral non-reducing TMJ disk displacement retarded mandibular growth bilaterally, the extent corresponding to mandibular retrognathia in man. Maxillary growth was also retarded, but to a lesser degree. Growth impairment fluctuated over time, the most striking retardation occurring during periods of general growth acceleration. This should be taken into consideration when orthodontic treatment, aimed at stimulating mandibular growth, is initiated in adolescent individuals with non-reducing TMJ disk displacement.
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4. |
- Eliasson, Lars, 1940, et al.
(författare)
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Dental plaque pH and micro-organisms during hyposalivation.
- 2006
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Ingår i: Journal of dental research. - 0022-0345. ; 85:4, s. 334-8
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Tidskriftsartikel (refereegranskat)abstract
- We have previously reported that minor gland and whole saliva flow rates and salivary proteins showed differences in individuals with primary Sj?gren's syndrome or head and neck radiation therapy, compared with controls (Eliasson et al., 2005). We now hypothesize that pH and number of acidogenic micro-organisms in dental plaque as well as saliva buffering capacity also differ in these individuals. Plaque pH was measured by the microtouch method up to 60 min after a sucrose rinse. Plaque collected from the same sites was analyzed for counts of total and acidic micro-organisms. Compared with their controls, the irradiated group but not the Sj?gren's syndrome group displayed significantly lower plaque pH, increased numbers of lactobacilli and Candida species, as well as reduced buffering capacity. Stepwise regression tests suggested that the buccal minor-salivary-gland secretion rate in the test groups and counts of mutans streptococci in the controls were of significant importance for dental plaque pH.
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6. |
- Fritschi, B Zinsli, et al.
(författare)
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Staphylococcus aureus and other bacteria in untreated periodontitis.
- 2008
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Ingår i: Journal of Dental Research. - 0022-0345 .- 1544-0591. ; 87:6, s. 589-593
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Tidskriftsartikel (refereegranskat)abstract
- Whether the subgingival microbiota differ between individuals with chronic and those with aggressive periodontitis, and whether smoking influences bacterial composition, is controversial. We hypothesized that the subgingival microbiota do not differ between sites in individuals with chronic or aggressive periodontitis, or by smoking status. Bacterial counts and proportional distributions were assessed in 84 individuals with chronic periodontitis and 22 with aggressive periodontitis. No differences in probing pocket depth by periodontal status were found (mean, 0.11 mm; 95% CI, 0.6 to 0.8, p = 0.74). Including Staphylococcus aureus, Parvimonas micra, and Prevotella intermedia, 7/40 species were found at higher levels in those with aggressive periodontitis (p < 0.001). Smokers had higher counts of Tannerella forsythia (p < 0.01). The prevalence of S. aureus in non-smokers with aggressive periodontitis was 60.5%. The null hypothesis was rejected, in that P. intermedia, S. aureus, and S. mutans were robust in diagnosing sites in individuals with aggressive periodontitis. S. aureus, S. sanguinis, and T. forsythia differentiated smoking status.
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7. |
- Häggman-Henrikson, Birgitta, et al.
(författare)
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Head Immobilization can Impair Jaw Function
- 2006
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Ingår i: Journal of Dental Research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 85:11, s. 1001-1005
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Tidskriftsartikel (refereegranskat)abstract
- Findings that jaw-opening/-closing relies on both mandibular and head movements suggest that jaw and neck muscles are jointly activated in jaw function. This study tested the hypothesis that rhythmic jaw activities involve an active repositioning of the head, and that head fixation can impair jaw function. Concomitant mandiular and head-neck movements were recorded during rhythmic jaw activities in 12 healthy adults, with and without fixation of the head. In four participants, the movement recording was combined with simultaneous registration of myoelectric activity in jaw and neck muscles. The results showed neck muscle activity during jaw opening with and without head fixation. Notably, head fixation led to reduced mandibular movements and shorter duration of jaw-opening/-closing cycles. The findings suggest recruitment of neck muscles in jaw activities, and that head fixation can impair jaw function. The results underline the jaw and neck neuromuscular relationship in jaw function.
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8. |
- Iwasaki, K, et al.
(författare)
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Amelotin--a Novel Secreted, Ameloblast-specific Protein
- 2005
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Ingår i: Journal of dental research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 84:12, s. 1127-1132
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Tidskriftsartikel (refereegranskat)abstract
- We aimed to analyze the differential gene expression in various murine dental tissues, expecting to find novel factors that are involved in tooth formation. We here describe the identification of a novel ameloblast-specific gene, amelotin (AMTN), by differential display polymerase chain-reaction (DD-PCR) analysis of microdissected ameloblasts, odontoblasts, dental pulp, and alveolar bone cells of 10-day-old mouse incisors. The conceptually translated protein sequence was unique and showed significant homology only with its human orthologue. The amelotin genes from mouse and human displayed a similar exon-intron structure and were expressed from loci on chromosomes 5 and 4, respectively, which have been associated with various forms of amelogenesis imperfecta. Expression of amelotin mRNA was restricted to maturation-stage ameloblasts in developing murine molars and incisors. Amelotin protein was efficiently secreted from transfected cells in culture. Taken together, our findings suggest that amelotin is a novel factor produced by ameloblasts that plays a critical role in the formation of dental enamel.
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9. |
- Lerner, Ulf H
(författare)
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Bone remodeling in post-menopausal osteoporosis.
- 2006
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Ingår i: Journal of dental research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 85:7, s. 584-95
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Tidskriftsartikel (refereegranskat)abstract
- Bone mass in the skeleton is dependent on the coordinated activities of bone-forming osteoblasts and bone-resorbing osteoclasts in discrete bone multi-cellular units. Remodeling of bone in these units is important not only for maintaining bone mass, but also to repair microdamage, to prevent accumulation of too much old bone, and for mineral homeostasis. The activities of osteoblasts and osteoclasts are controlled by a variety of hormones and cytokines, as well as by mechanical loading. Most importantly, sex hormones are very crucial for keeping bone mass in balance, and the lack of either estrogen or testosterone leads to decreased bone mass and increased risk for osteoporosis. The prevalence of osteoporotic fractures is increasing dramatically in the Western part of the world and is a major health problem in many countries. In the present review, the cellular and molecular mechanisms controlling bone remodeling and the influence of sex hormones on these processes are summarized. In a separate paper in this issue, the pathogenesis of post-menopausal osteoporosis will be compared with that of inflammation-induced bone remodeling, including the evidence for and against the hypothesis that concomitant post-menopausal osteoporotic disease influences the progression of periodontal disease.
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10. |
- Lerner, Ulf H
(författare)
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Inflammation-induced bone remodeling in periodontal disease and the influence of post-menopausal osteoporosis.
- 2006
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Ingår i: Journal of dental research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 85:7, s. 596-607
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Tidskriftsartikel (refereegranskat)abstract
- During physiological conditions, the skeleton is remodeled in so-called bone multi-cellular units. Such units have been estimated to exist at 1-2 x 10(6) sites in the adult skeleton. The number and activities of these units are regulated by a variety of hormones and cytokines. In post-menopausal osteoporosis, lack of estrogen leads to increased numbers of bone multi-cellular units and to uncoupling of bone formation and bone resorption, resulting in too little bone laid down by osteoblasts compared with the amount of bone resorbed by osteoclasts. Inflammatory processes in the vicinity of the skeleton, e.g., marginal and apical periodontitis, will affect the remodeling of the nearby bone tissue in such a way that, in most patients, the amount of bone resorbed exceeds that being formed, resulting in net bone loss (inflammation-induced osteolysis). In some patients, however, inflammation-induced bone formation exceeds resorption, and a sclerotic lesion will develop. The cellular and molecular pathogenetic mechanisms in inflammation-induced osteolysis and sclerosis are discussed in the present review. The cytokines believed to be involved in inflammation-induced remodeling are very similar to those suggested to play crucial roles in post-menopausal osteoporosis. In patients with periodontal disease and concomitant post-menopausal osteoporosis, the possibility exists that the lack of estrogen influences the activities of bone cells and immune cells in such a way that the progression of alveolar bone loss will be enhanced. In the present paper, the evidence for and against this hypothesis is presented.
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11. |
- Lundgren, T, et al.
(författare)
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Impaired cytotoxicity in Papillon-Lefèvre syndrome
- 2005
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Ingår i: Journal of Dental Research. - 0022-0345 .- 1544-0591. ; 84:5, s. 414-417
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Tidskriftsartikel (refereegranskat)abstract
- Papillon-Lefèvre syndrome (PLS), palmoplantar hyperkeratosis with periodontitis, has been genetically characterized. However, suspected associated immune dysfunctions remain elusive. The purpose of this study was to evaluate peripheral blood lymphocyte levels and natural killer (NK) cell cytotoxicity in PLS. Twenty patients and 20 healthy controls were examined. Peripheral blood lymphocytes were analyzed by flow cytometry for surface markers. NK cell cytotoxicity against K562 cells was determined by means of a 51Cr release assay. White blood cell differential and proportions of B-, T-, T-helper, T-suppressor, and NK cells revealed only sporadic borderline variations from control values. In contrast, NK cell cytotoxicity was consistently and severely depressed (32-53% of control values) in all patients. To the best of our knowledge, this newly described impairment of NK cell cytotoxic function is the first consistent immune dysfunction reported in PLS. This suggests that the impaired NK cell cytotoxicity might contribute to the pathogenesis of PLS-associated periodontitis.
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12. |
- Lundgren, T, et al.
(författare)
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Impaired cytotoxicity in Papillon-Lefèvre syndrome.
- 2005
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Ingår i: Journal of Dental Research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 84:5, s. 414-417
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Tidskriftsartikel (refereegranskat)abstract
- Papillon-Lefèvre syndrome (PLS), palmoplantar hyperkeratosis with periodontitis, has been genetically characterized. However, suspected associated immune dysfunctions remain elusive. The purpose of this study was to evaluate peripheral blood lymphocyte levels and natural killer (NK) cell cytotoxicity in PLS. Twenty patients and 20 healthy controls were examined. Peripheral blood lymphocytes were analyzed by flow cytometry for surface markers. NK cell cytotoxicity against K562 cells was determined by means of a 51Cr release assay. White blood cell differential and proportions of B-, T-, T-helper, T-suppressor, and NK cells revealed only sporadic borderline variations from control values. In contrast, NK cell cytotoxicity was consistently and severely depressed (32-53% of control values) in all patients. To the best of our knowledge, this newly described impairment of NK cell cytotoxic function is the first consistent immune dysfunction reported in PLS. This suggests that the impaired NK cell cytotoxicity might contribute to the pathogenesis of PLS-associated periodontitis.
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13. |
- Mucci, LA, et al.
(författare)
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Environmental and heritable factors in the etiology of oral diseases--a population-based study of Swedish twins
- 2005
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Ingår i: Journal of dental research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 84:9, s. 800-805
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Tidskriftsartikel (refereegranskat)abstract
- A population-based twin study is a useful design for quantification of the effects of genes and environmental factors in disease etiology. We used data from 10,000 Swedish twin pairs to quantify genetic and environmental contributions to tooth loss and periodontal health. Oral health information was obtained from telephone interviews. Structural equation models measured the relative importance of genetic and environmental factors. Genetic factors contributed to 14% of variation in tooth loss among women, and 39% among men. Non-shared environmental factors accounted for one-quarter of risk; environmental factors shared by twins comprised the remainder. Heritability estimates of periodontal disease were 39% and 33% for women and men, respectively, while non-shared environmental factors accounted for the remaining variation. Heritability for both conditions varied as a function of age and smoking status. Analysis of data from this large, population-based study demonstrates a moderate role of genetic factors in oral diseases, and suggests potential gene-environment interactions.
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14. |
- Palmqvist, Py, 1968-, et al.
(författare)
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IL-1beta and TNF-alpha regulate IL-6-type cytokines in gingival fibroblasts.
- 2008
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Ingår i: Journal of Dental Research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 87:6, s. 558-563
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Tidskriftsartikel (refereegranskat)abstract
- Interleukin-6 (IL-6)-type cytokines are pleiotropic molecules capable of stimulating bone resorption and expressed by numerous cell types. In the present study, we tested the hypothesis that gingival fibroblasts may exert local osteotropic effects through production of IL-6 and related cytokines. IL-6-type cytokine expression and regulation by IL-1beta and tumor necrosis factor-alpha (TNF-alpha) were studied in fibroblasts from the non-inflamed gingiva of healthy individuals. Constitutive mRNA expression of IL-6, IL-11, and leukemia inhibitory factor (LIF), but not of oncostatin M (OSM), was demonstrated, as was concentration-dependent stimulation of IL-6 and LIF mRNA and of protein by IL-1beta and TNF-alpha. IL-11 mRNA and protein were concentration-dependently stimulated by IL-1beta. The signaling pathway involved in IL-6 and LIF mRNA stimulation involved MAP kinases, but not NF-kappaB. The findings support the view that resident cells may influence the pathogenesis of periodontal disease through osteotropic IL-6-type cytokine production mediated by activation of MAP kinases. Abbreviations: IL-1alpha (interleukin-1alpha); IL-1beta (interleukin-1beta); IL-6 (interleukin-6); IL-11 (interleukin-11); LIF (leukemia inhibitory factor); OSM (oncostatin M); alpha(1)-coll. I (alpha(1)-collagen I); ALP (alkaline phosphatase); BMP-2 (bone morphogenetic protein-2); OC (osteocalcin); BSP (bone sialoprotein); TNFR I (tumor necrosis factor receptor I); TNFR II (tumor necrosis factor receptor II); IL-1R1 (interleukin-1 receptor 1); GAPDH (glyceraldehyde-3-phosphate dehydrogenase); RPL13A (ribosomal protein L13A); mRNA (messenger ribonucleic acid); cDNA (complementary deoxyribonucleic acid); PCR (polymerase chain-reaction); BCA (bicinchoninic acid); ELISA (enzyme-linked immunosorbent assay); alpha-MEM (alpha modification of Minimum Essential Medium); and FCS (fetal calf serum).
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15. |
- Sandberg, Elisabeth, 1956, et al.
(författare)
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Low HEMA conjugation induces high autoantibody titer in mice.
- 2005
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Ingår i: Journal of dental research. - 0022-0345. ; 84:6, s. 537-41
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Tidskriftsartikel (refereegranskat)abstract
- 2-hydroxyethylmethacrylate (HEMA) is a known causal agent of hypersensitivity to resin composites. We have reported that immunization with HEMA conjugated to mouse serum albumin (MSA) induces an autoantibody response in mice. In this study, we investigated both the activity and the avidity of autoantibodies induced by immunization with various HEMA conjugations to MSA. Female Balb/c mice were given MSA carrying 3, 7, 15, or 22 HEMA molecules. Antigen-specific IgG and IgE antibodies were determined by ELISA, and average antibody avidity by thiocyanate dissociation. Immunization with MSA carrying the lowest number of HEMA molecules induced a significantly higher IgG and IgE anti-MSA autoantibody response, with significantly higher IgG antibody avidity, than did the more heavily conjugated preparations. The results suggest that the lower the degree of HEMA conjugation to self-protein, the higher the risk for autoantibody production to the carrier protein. These findings suggest a mechanism of potential relevance in humans.
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16. |
- Tanner, Anne C R, et al.
(författare)
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Subgingival and tongue microbiota during early periodontitis.
- 2006
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Ingår i: Journal of Dental Research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 85:4, s. 318-323
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Tidskriftsartikel (refereegranskat)abstract
- Periodontal infections have a microbial etiology. Association of species with early disease would be useful in determining which microbes initiate periodontitis. We hypothesized that the microbiota of subgingival and tongue samples would differ between early periodontitis and health. A cross-sectional evaluation of 141 healthy and early periodontitis adults was performed with the use of oligonucleotide probes and PCR. Most species differed in associations with sample sites; most subgingival species were associated with subgingival samples. Few species were detected more frequently in early periodontitis by DNA probes. Porphyromonas gingivalis and Tannerella forsythia (Tannerella forsythensis) were associated with early periodontitis by direct PCR. In conclusion, the microbiota of tongue samples was less sensitive than that of subgingival samples in detecting periodontal species, and there was overlap in species detected in health and early periodontitis. Detection of periodontal pathogens in early periodontitis suggests an etiology similar to that of more advanced disease.
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17. |
- Tohnak, S., et al.
(författare)
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Synthesizing dental radiographs for human identification
- 2007
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Ingår i: Journal of Dental Research. - 0022-0345 .- 1544-0591. ; 86:11, s. 1057-1062
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Tidskriftsartikel (refereegranskat)abstract
- The task of identifying human remains based on dental comparisons of post mortem (PM) and ante mortem (AM) radiographs is labor-intensive, subjective, and has several drawbacks, including: inherently poor image quality, difficulty matching the viewing angles in PM radiographs to those taken AM, and the fact that the state of the dental remains may entirely preclude the possibility of obtaining certain types of radiographs PM. The aim of the present study was to investigate the feasibility of using radiograph-like images reconstructed from PM x-ray computed tomography (CT) data to overcome the shortcomings of conventional radiographic comparison. Algorithms for computer synthesis of panoramic, periapical, and bitewing images are presented. The algorithms were evaluated with data from clinical examinations of two persons. The results demonstrate the efficacy of the CT-based approach and that, in comparison with conventional radiographs, the synthesized images exhibit minimal geometric distortion, reduced blurring, and reduced superimposition of oral structures.
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