Pathogens and host immunity in the ancient human oral cavity.

Calcified dental plaque (dental calculus) preserves for millennia and entraps biomolecules from all domains of life and viruses. We report the first, to our knowledge, high-resolution taxonomic and protein functional characterization of the ancient oral microbiome and demonstrate that the oral cavity has long served as a reservoir for bacteria implicated in both local and systemic disease. We characterize (i) the ancient oral microbiome in a diseased state, (ii) 40 opportunistic pathogens, (iii) ancient human-associated putative antibiotic resistance genes, (iv) a genome reconstruction of the periodontal pathogen Tannerella forsythia, (v) 239 bacterial and 43 human proteins, allowing confirmation of a long-term association between host immune factors, 'red complex' pathogens and periodontal disease, and (vi) DNA sequences matching dietary sources.

Root malformation associated with a cervical mineralized diaphragm--a distinct form of tooth abnormality?

Objective: Deviations in length and shape of tooth roots result from hard tissue resorption or occur as a developmental disorder. The purpose of this report is to present a type of root malformation which seems to have gone unreported so far.

Study Design: Two patients showing severely dysplastic roots of all permanent first molars were evaluated using radiography, histology as well as scanning and transmission electron microscopy.

Resorption pattern and radiographic diagnosis of invasive cervical resorption. A correlative microCT, scanning electron and light microscopic evaluation of a case series.

The aim of this study was to evaluate, whether and how the histologic structure of invasive cervical resorption (external granulomas) affect their clinical radiographic diagnosis. For this purpose, nine more or less intact extracted teeth, of which intraoral radiographs were available, were processed for examination in the scanning electron (SEM) and light microscope. From some of the specimens non-decalcified ground sections were prepared and some were decalcified for preparation of histologic sections.

E-cadherin regulates the behavior and fate of epithelial stem cells and their progeny in the mouse incisor.

Stem cells are essential for the regeneration and homeostasis of many organs, such as tooth, hair, skin, and intestine. Although human tooth regeneration is limited, a number of animals have evolved continuously growing teeth that provide models of stem cell-based organ renewal. A well-studied model is the mouse incisor, which contains dental epithelial stem cells in structures known as cervical loops.

MRI of the temporo-mandibular joint: which sequence is best suited to assess the cortical bone of the mandibular condyle? A cadaveric study using micro-CT as the standard of reference.

Objective: To determine the best suited sagittal MRI sequence out of a standard temporo-mandibular joint (TMJ) imaging protocol for the assessment of the cortical bone of the mandibular condyles of cadaveric specimens using micro-CT as the standard of reference.

Methods: Sixteen TMJs in 8 human cadaveric heads (mean age, 81 years) were examined by MRI. Upon all sagittal sequences, two observers measured the cortical bone thickness (CBT) of the anterior, superior and posterior portions of the mandibular condyles (i.

Discoloration of teeth from tetracyclines--even today?

The aim of this study was to examine whether brownish crown and root discoloration of wisdom teeth was related to treatment of acne with tetracyclines. For this purpose, 17 discolored third molars from nine patients were embedded without being decalcified, ground along the tooth axis, and examined using fluorescence microscopy. A thorough medical history served to determine the start and duration of any administration of tetracyclines.

Rare dental peculiarities associated with the hypomyelinating leukoencephalopathy 4H syndrome/ADDH.

Purpose: 4H syndrome/ADDH, a disease of the cerebral white matter, seems to be associated with delayed tooth eruption and other dental abnormalities, which so far could not be assessed conclusively-mainly because patients were too young. The aim of this study was to characterize these abnormalities in a sample of patients old enough for a reliable assessment.

Methods: Three children, all diagnosed with 4H syndrome/ADDH, were followed from approximately 4 to 10 years of age and examined clinically and radiographically.

Misfit of suprastructures on implants processed by electrical discharge machining or the Cresco method.

Objective: To assess the accuracy of fit of frameworks on implants processed with electrical discharge machining (EDM) or the Cresco technique (Astra Tech).

Method And Materials: On 12 identical master casts with implants at positions 9(21), 11(23), and 13(25), high-gold alloy frameworks were produced by standard casting procedure. Six frameworks were used for the Cresco technique (group CRE) by employing specific fixed partial denture supports.

Enamel-free teeth: Tbx1 deletion affects amelogenesis in rodent incisors.

TBX1 is a principal candidate gene for DiGeorge syndrome, a developmental anomaly that affects the heart, thymus, parathyroid, face, and teeth. A mouse model carrying a deletion in a functional region of the Tbx1 gene has been extensively used to study anomalies related to this syndrome. We have used the Tbx1 null mouse to understand the tooth phenotype reported in patients afflicted by DiGeorge syndrome.

Deletion of BMP7 affects the development of bones, teeth, and other ectodermal appendages of the orofacial complex.

Sequential and reciprocal epithelial-mesenchymal interactions govern the development of most tissues and organs of the craniofacial region. Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-beta family of secreted signaling molecules that have long been implied to have a significant contribution in this process. However, evidence for such a role during craniofacial development is largely missing.

Distribution of insulin-like growth factors in condylar hyperplasia.

Condylar hyperplasia (CH) is a local overgrowth of the condylar process of the temporomandibular joint (TMJ) of unknown etiology. Probably, growth factors like the insulin-like growth factors (IGFs) are involved in its pathogenesis. Specimens from 12 patients were investigated histologically and immunohistochemically to obtain the distribution of the IGFs-I and -II and the IGF1 receptor.

Biocompatibility of Beta-tricalcium phosphate root replicas in porcine tooth extraction sockets - a correlative histological, ultrastructural, and x-ray microanalytical pilot study.

This investigation studies porcine tissue response in tooth extraction sockets treated with root replicas made out of Beta-tricalcium phosphate (Beta-TCP; Beta-Ca(3)(PO(4))(2)) granules, molded and held together by thermal fusion of a thin film of polyglycolic-polylactic acid copolymer. Six left mandibular third incisors (n (1)/4 6) of experimental pigs are treated with the root replicas and four contralateral incisors are used as nontreated controls (n (1)/4 4). Two animals each were killed at 20, 40, and 60 weeks of observation periods.

Performance of visual inspection, electrical conductance and laser fluorescence in detecting occlusal caries in vitro.

The aim of this study was to compare visual inspection (VI) and electrical conductance (EC) and laser fluorescence (LF) measurements in detecting occlusal caries. VI was based on fissure discoloration and performed with the naked eye. EC was measured with the ECM device (Lode Diagnostic, Groningen, The Netherlands), and LF was assessed with the DIAGNOdent apparatus (KaVo, Biberach, Germany).

Pulpal response to Er:YAG laser drilling of dentine in healthy human third molars.

Background And Objectives: Maintenance of pulpal health is a critical prerequisite for successful application of light amplification by stimulated emission of radiations (lasers) in the hard tissue management of vital teeth. The purpose of this study was to investigate the short- and long-term pulpal effects to cavity-preparations in healthy human teeth using erbium-doped:yttrium, aluminum, and garnet (Er:YAG) laser.

Materials And Methods: A total of seven healthy third molars that were to be removed due to space-problem were used.

Ciliated epithelium-lined radicular cysts.

Objective: This report describes 3 cases of ciliated epithelium-lined radicular cysts among 256 apical periodontitis lesions and also illustrates the occurrence of an Actinomyces-infected periapical cyst.

Study Design: Serial and step serial sections of 256 plastic-embedded root apices with attached apical periodontitis lesions that were prepared for a previous investigation were reviewed for the presence of ciliated epithelium-lined radicular cysts. The lesions that were found to have such epithelial lining were examined in a transmission electron microscope to elaborate the fine structure of the ciliated cells.

Factors affecting degeneration in human temporomandibular joints as assessed histologically.

The influence of sex, age, tooth loss, and articular disc position on temporomandibular joint (TMJ) degeneration was evaluated in specimens collected at autopsy from 15 women and 38 men ranging in age from 15 to 92 yr. The position of the articular discs was classified as normal or abnormal, tooth loss was both counted and categorized. Degenerative changes of the articular tissues were assessed histologically and quantified, taking into account both the severity of structural alterations and their extension along the articular surface.