The dentin-enamel junction (DEJ) is the border where two different mineralized structures - enamel and dentin - meet. The protein-rich DEJ, together with the inner enamel region of mature teeth, is known to exhibit higher fracture toughness and crack growth resistance than bulk phase enamel. However, an explanation for this behavior has been hampered by the lack of compositional information for the DEJ and the adjacent enamel organic matrix (EOM). We studied proteomes of the DEJ and EOM of healthy human molars and compared them with dentin and enamel proteomes from the same teeth. These tissues were cut out of tooth sections by laser capture microdissection, proteins were extracted and cleaved by trypsin, then processed by liquid chromatography coupled to tandem mass spectrometry to analyze the proteome profiles of these tissues. This study identified 46 proteins in DEJ and EOM. The proteins identified have a variety of functions, including calcium ion-binding, formation of extracellular matrix, formation of cytoskeleton, cytoskeletal protein binding, cell adhesion, and transport. Collagens were identified as the most dominant proteins. Tissue-specific proteins, such as ameloblastin and amelogenin, were also detected. Our findings reveal new insight into proteomics of DEJ and EOM, highly mineralized tissues that are obviously difficult to analyze.

• MeSH
• chromatografie kapalinová MeSH
• dentin * MeSH
• lidé MeSH
• mikrodisekce MeSH
• moláry * MeSH
• proteiny metabolismus   MeSH
• proteom analýza   MeSH
• proteomika metody   MeSH
• tandemová hmotnostní spektrometrie MeSH
• zubní sklovina * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Using the distal molar of a minipig as a model, we studied changes in the microstructural characteristics of apatite crystallites during enamel maturation (16-23 months of postnatal age), and their effects upon the mechanical properties of the enamel coat. The slow rate of tooth development in a pig model enabled us to reveal essential heterochronies in particular components of the maturation process. The maturation changes began along the enamel-dentine junction (EDJ) of the trigonid, spreading subsequently to the outer layers of the enamel coat to appear at the surface zone with a 2-month delay. Correspondingly, at the distal part of the tooth the timing of maturation processes is delayed by 3-5 month compared to the mesial part of the tooth. The early stage of enamel maturation (16-20 months), when the enamel coat is composed almost exclusively of radial prismatic enamel, is characterized by a gradual increase in crystallite thickness (by a mean monthly increment of 3.8 nm); and an increase in the prism width and thickness of crystals composed of elementary crystallites. The late stage of maturation (the last two months prior to tooth eruption), marked with the rapid appearance of the interprismatic matrix (IPM) during which the crystals densely infill spaces between prisms, is characterized by an abrupt decrease in microstrain and abrupt changes in the micromechanical properties of the enamel: a rapid increase in its ability to resist long-term load and its considerable hardening. The results suggest that in terms of crystallization dynamics the processes characterizing the early and late stage of mammalian enamel maturation represent distinct entities. In regards to common features with enamel formation in the tribosphenic molar we argue that the separation of these processes could be a common apomorphy of mammalian amelogenetic dynamics in general.

• MeSH
• dentin diagnostické zobrazování   metabolismus   MeSH
• krystalografie MeSH
• miniaturní prasata MeSH
• moláry diagnostické zobrazování   růst a vývoj   MeSH
• prasata MeSH
• prořezávání zubů fyziologie   MeSH
• zubní sklovina diagnostické zobrazování   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

OBJECTIVES: To evaluate the sealing performance of self-etch adhesives (SEA) after smear layer deproteinization with chemo-mechanical caries removal agents (CRA) to enamel and dentin cavity walls in comparison with 6% NaOCl smear layer deproteinizing. METHODS: Eighty extracted bovine incisors with tapered cylindrical cavities (2.5 mm upper diameter, 1.5 mm lower diameter, 2 mm depth) at the cemento-enamel junction were randomly divided into four pre-treatment groups; no treatment (control), Papacarie (papain enzyme-based CRA), Carisolv (NaOCl-based CRA), and 6% NaOCl. After pretreatment, G-Bond Plus (GBP, one-step SEA) or Clearfil SE Bond 2 (CSE, two-step SEA) was applied to the pre-treated cavity, and then filled with a flowable resin composite (Clearfil Majesty ES Flow). Gap formations at the enamel and dentin lateral walls, and on the dentin cavity floor were investigated using swept-source optical coherence tomography (SS-OCT) after 24-h water storage at 37 °C. Deproteinizing effects of the tested agents on smear layer-covered enamel and dentin were quantified by changes in the amide:phosphate ratio using ATR-FTIR analysis. RESULTS: Papacarie significantly reduced gap formation with both self-etch adhesives at all locations, compared to the control group (p < 0.05). In contrast, increased gap formation was observed with Carisolv and NaOCl. In most groups, CSE exhibited significantly lower gap formation than GBP (p < 0.05). ATR-FTIR revealed a significant decrease in the amide:phosphate ratio for all the deproteinizing agents (p < 0.05). CONCLUSIONS: Chemo-mechanical CRAs could effectively remove the organic phase of enamel and dentin smear layer. The papain enzyme-based gel Papacarie could improve the sealing performance of the self-etch adhesives to both enamel and dentin.

• MeSH
• adheziva MeSH
• dentin MeSH
• dentinová adheziva MeSH
• pryskyřičné cementy MeSH
• skot MeSH
• složené pryskyřice MeSH
• smear layer * MeSH
• testování materiálů MeSH
• vazba zubní * MeSH
• zubní cementy MeSH
• zubní sklovina MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• abraze zubů diagnóza   etiologie   terapie   MeSH
• citlivost dentinu patofyziologie   terapie   MeSH
• eroze zubů diagnóza   etiologie   terapie   MeSH
• lidé MeSH
• nemoci zubů * diagnóza   chirurgie   terapie   MeSH
• preventivní zubní lékařství MeSH
• stomatologická péče MeSH
• zubní krček patofyziologie   zranění   MeSH
• Check Tag
• lidé MeSH

Peroxidové bělicí přípravky mohou silným oxidačním účinkem působit na dříve zhotovené kompozitní výplně. Cílem práce bylo sledování vlivu bělicích systémů na dlouhodobou stabilitu okrajového uzávěru kompozitních výplní a na odolnost povrchu těchto materiálů. Studie byla provedena standardním testem mikroleakage na výplních V. třídy s okrajem ve sklovině a dentinu. Použity byly dvě skupiny vzorků (každá n=36) připravené s total-etch adhezivním systémem Gluma Comfort Bond a self-etching adhezivem iBond, vždy v kombinaci s mikrohybridním kompozitním materiálem Charisma. Peroxidový bělicí gel Opalescence PF 20 %, s obsahem 20% karbamid peroxidu určený pro domácí bělení, byl na zhotovené výplně (n=12) aplikován 25krát. Kontrolní skupiny po 12 vzorcích byly exponovány v destilované vodě po dobu 24 hodin a 2 měsíců. Změny povrchu kompozitního materiálu (n=5) byly charakterizovány měřením tvrdosti po 0, 2, 7, 14, a 25 aplikacích gelu a porovnávány s kontrolní skupinou (n=5) exponovanou po dobu 2 měsíců v destilované vodě. U vybraných vzorků byla hodnocena morfologie povrchu elektronovou mikroskopií. Po aplikaci peroxidového bělicího gelu nebyly prokázány významné změny okrajového uzávěru. U adheziva Gluma Comfort Bond v důsledku jeho dobrých adhezních schopností, u systému iBond proto, že vlivem jeho snížené adheze ke sklovině docházelo k porušení okrajového uzávěru již na počátku experimentu. Významné projevy degradace byly naopak pozorovány u kompozitního materiálu, kdy po aplikaci bělicího gelu byla nalezena výrazná povrchová porozita spojená s poklesem tvrdosti kompozitu.

Peroxide bleaching systems may affect resin composite restorations through their strong oxidative effect. The objective was to investigate the influence of bleaching systems on long-term stability of marginal integrity of composite restorations and composite surface resistance. Class V cavities were prepared at the enamel-dentine junction and filled using a total-etch adhesive system Gluma Comfort Bond (n=36) and self-etching adhesive iBond (n=36) in combination with the microhybrid resin composite material Charisma. The peroxide bleaching gel Opalescence PF 20% (20 wt. % carbamide peroxide) was applied 25 times on the restorations. The control groups were exposed to distilled water for 24 hours and two months before a microleakage test was performed. Composite hardness was characterized after 0, 2, 7, 14 and 25 applications of the gel and compared with the control group (each n=5) exposed to distilled water for two months. Surface morphology was evaluated using scanning electron microscopy. After the gel application no significant changes in marginal integrity were found for both groups of samples. With Gluma Comfort Bond due to its high bonding performance and with iBond due to its decreased performance on enamel causing marginal integrity failure at the beginning of the experiment. On the other hand, pronounced surface porosity and decreased hardness of the composite material indicated its significant degradation in the presence of the bleaching gel.

• MeSH
• bělení zubů metody   škodlivé účinky   MeSH
• financování organizované MeSH
• peroxidy terapeutické užití   MeSH
• složené pryskyřice MeSH
• testy tvrdosti MeSH
• zubní marginální adaptace MeSH
• Publikační typ
• přehledy MeSH

Prematurely erupted teeth are rare in fullterm neonates and extremely rare in prematurely delivered infants. The aim of this study was to present macroscopic and scanning electron microscopy (SEM) investigations of prematurely erupted primary teeth of preterm very low birthweight (VLBW) and extremely low birthweight (ELBW) infants. Three preterm VLBW and ELBW infants with prematurely erupted lower incisors were examined. The dental examination assessed the type, location, clinical appearance, and degree of mobility of the prematurely erupted teeth. The structural appearance of enamel and dentin of three extracted and longitudinally sectioned prematurely erupted teeth was investigated with scanning electron microscopy (SEM). Lower incisors were rootless with hypermobility. The surface of enamel of the prematurely erupted primary teeth was hypoplastic and hypomineralized and had a typical "honeycomb" appearance in SEM. The aprismatic type of enamel was visible in some regions. The neonatal line separating the layer of prenatal enamel from postnatal enamel was observed. The enamel prisms were interconnected by interprismatic substances, and cross-striations of prisms were visible. Dentin presented a typical tubular character. The dentinal layer near the enamel dentin junction had Y-shaped branching of dentinal tubules. On the pulpal side, dentin had a globular character. The macroscopic and SEM investigations particularly revealed alterations in enamel, while the dentin of neonatal teeth had a nearly normal appearance.

• MeSH
• dentin * MeSH
• kojenec MeSH
• lidé MeSH
• mikroskopie elektronová rastrovací MeSH
• novorozenec nedonošený * MeSH
• novorozenec MeSH
• řezáky MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH

Novel mRNA isoforms encoding the enamel matrix proteins amelin-1, amelin-2 and ameloblastin have been recently described. We have applied detailed immunohistochemical as well as non-radioactive in situ hybridization analyses to follow amelin-1 expression in developing rat incisors and molars. We constructed an expression vector, overproduced recombinant amelin in Escherichia coli and prepared an antibody. In addition to the previously reported amelin mRNA expression patterns in ameloblasts, the amelin message was also detected in pulpal mesenchymal cells including preodontoblasts and young odontoblasts. The signal in these cells persisted until deposition of mantle dentin became evident. The immunolocalization of amelin-1 in preodontoblasts and ameloblasts essentially followed the pattern of mRNA expression. The most intense staining was found in the enamel matrix adjacent to secretory ameloblasts. Focal accumulations of immunoreactive material were found at the dentinoenamel junction during the maturation stage. Also, using 5'-RACE (Rapid Amplification of cDNA Ends) we could confirm only amelin-1 and ameloblastin messages in the total RNA pool from rat molars and conclude that amelin-2 is a truncated form of ameloblastin. The sequential expression of amelin in mesenchymal and epithelial cells suggests it plays a role in cell differentiation during early tooth development.

• MeSH
• ameloblasty metabolismus   MeSH
• DNA primery genetika   MeSH
• epitelové buňky metabolismus   MeSH
• hybridizace in situ MeSH
• imunohistochemie MeSH
• komplementární DNA genetika   MeSH
• krysa rodu rattus MeSH
• messenger RNA genetika   MeSH
• mezoderm metabolismus   MeSH
• odontoblasty metabolismus   MeSH
• odontogeneze * genetika   MeSH
• potkani Sprague-Dawley MeSH
• proteiny zubní skloviny * genetika   metabolismus   MeSH
• rekombinantní fúzní proteiny genetika   MeSH
• sekvence nukleotidů MeSH
• vývojová regulace genové exprese MeSH
• zubní sklovina cytologie   metabolismus   růst a vývoj   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• práce podpořená grantem MeSH

• MeSH
• histologie MeSH

• Konspekt
• Anatomie člověka a srovnávací anatomie
• NLK Obory
• histologie
• NLK Publikační typ
• učebnice vysokých škol

• Klíčová slova
• Teoretické obory,
• MeSH
• biologie buňky MeSH
• histologie MeSH
• tkáně anatomie a histologie   MeSH

• NLK Obory
• histologie
• cytologie, klinická cytologie

• MeSH
• histologie MeSH

• Konspekt
• Anatomie člověka a srovnávací anatomie
• Učební osnovy. Vyučovací předměty. Učebnice
• NLK Obory
• histologie
• NLK Publikační typ
• kolektivní monografie
• učebnice vysokých škol