bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunohistochemical detection of phosphorylated Akt, PI3K, and PTEN in ameloblastic tumors
Authors: Kumamoto Hiroyuki , Ooya Kiyoshi 
Published: June 2007

Objective:  To evaluate roles of the Akt signaling pathway in oncogenesis and cytodifferentiation of odontogenic tumors, expression of phosphorylated Akt (pAkt), PI3K, and PTEN was analyzed in ameloblastic tumors as well as in tooth germs.Methods:  11 tooth germs, 40 ameloblastomas, and 5 malignant ameloblastic tumors were examined immunohistochemically with antibodies against pAkt, PI3K, and PTEN.Results:  Immunoreactivity for pAkt, PI3K, and PTEN was detected predominantly in odontogenic epithelial cells near the basement membrane in tooth germs and ameloblastic tumors. The levels of immunoreactivity for pAkt and PI3K were slightly higher in ameloblastic tumors than in tooth germs. Plexiform ameloblastomas showed significantly higher expression of PI3K than follicular ameloblastomas, and PI3K immunoreactivity in ameloblastomas without cellular variation was significantly higher than that in acanthomatous ameloblastomas. The level of PTEN immunoreactivity was significantly lower in ameloblastomas than in tooth germs.Conclusion:  Expression of pAkt, PI3K, and PTEN in tooth germs and ameloblastic tumors suggests that these signaling molecules regulate cell survival and growth in normal and neoplastic odontogenic tissues by mediating growth factor signals. Increased expression of pAkt and PI3K and decreased expression of PTEN in ameloblastic tumors may participate in oncogenesis of odontogenic epithelium by activating the Akt signaling pathway.
Low‐frequency noise effects on the parotid gland of the Wistar rat
Authors: Oliveira PMA , Pereira da Mata ADS , Martins dos Santos JAM , Da Silva Marques DN , Branco NC , Silveira JML , Correia da Fonseca JCD 
Published: June 2007

Background:  Long‐term low‐frequency noise (LFN) (≤500 Hz) exposure is known to cause extracellular matrix proliferation by fibrosis in the absence of inflammatory signs.Aim:  We have examined the morphofunctional alterations of the parotid glands of Wistar rats exposed to LFN. The hypothesis is that the parotid glands are a target for LFN‐induced lesions.Materials and methods:  Ten rats were exposed to LFN for 2184 consecutive hours while 10 rats were kept under similar conditions but in silence for control purposes. The parotid glands were surgically removed. One gland was sectioned and stained with hematoxylin–eosin and periodic acid Schiff for light microscopy observation. The other was used for functional amylase secretion measurements, basal and nerve‐mediated [with electrical field stimulation (EFS)] and secretagogue‐evoked secretion [acetylcholine (ACh) 10‐‐5 m] with established fluorimetric techniques.Results:  All the rats exposed to LFN showed marked morphological lesions including vacuolar degeneration, hyalinization, cell death and blood vessels wall focal thickening. No morphological changes were detected in the control group. The functional results presented significantly diminished basal, EFS and ACh‐evoked amylase secretion when compared with the control group.Conclusion:  These results suggest that the parotid gland is a target for LFN‐induced lesions with an impairment of its function.
FGF signaling in mandibular skeletogenesis
Authors: Mina M , Havens B 
Published: June 2007

Structured AbstractAuthors –  Mina M, Havens BObjective –  To examine the functions of FGF/FGFR signaling during mandibular skeletogenesis in ovo.Design –  We examined the effects of inhibition of FGF signaling during mandibular skeletogenesis by overexpressing replication‐competent RCAS virus encoding a truncated form of FGFR3 in the chicken mandibular process between stages 17 and 26.Results –  Injection of RCAS‐dnFGFR3 into the developing mandible resulted in abnormalities in a stage‐ and region‐dependent manner. Injection at early stages of development resulted in the truncation of Meckel's cartilage, severely reduced outgrowth of the mandibular process and absence of five of the mandibular bones. Injection at later stages did not affect the outgrowth of the mandibular process and Meckel's cartilage but resulted in abnormalities in mandibular osteogenesis in a region‐specific manner. The bones in the more caudal region were frequently truncated whereas bones in the more rostral regions such as dentary and splenial bones were frequently absent.Conclusion –  Together these experiments have revealed essential roles for FGF/FGFR signaling in the elongation of Meckel's cartilage, development of osteogenic condensations and appositional growth of mandibular bones.
Subclinical features in non‐syndromic cleft lip with or without cleft palate (CL/P): review of the evidence that subepithelial orbicularis oris muscle defects are part of an expanded phenotype for CL/P*
Authors: Marazita ML 
Published: June 2007

Structured AbstractAuthor – Marazita MLObjectives – Non‐syndromic cleft lip with or without cleft palate (CL/P) is a common, complex birth defect with a wide phenotypic spectrum. This review summarizes the evidence that subepithelial (occult) defects of the superiororbicularis oris(OO) muscle represent the mildest form of the lip portion of CL/P.Experimental Design – The rate of OO defects was assessed via ultrasound in non‐CL/P relatives of individuals with CL/P and compared with controls. Descriptive histology of OO muscles from cadavers was carried out. BMP4 was sequenced in non‐CL/P individuals with OO defects vs. controls.Results – 1) Non‐CL/P relatives of individuals with overt CL/P have a significantly increased frequency of OO defects compared with controls with no family history of CL/P; 2) Preliminary histological studies of cadaver OO muscles show a pattern of disorganized muscle fibers in an individual with OO discontinuities as seen on ultrasound compared with another individual with no OO defect. That is, the defects seen on ultrasound appear to have an anatomical basis; 3) Sequencing BMP4 found a significant increase in potentially damaging mutations in individuals with OO defects vs. controls.Conclusions – Taken together, these data provide significant support for the hypothesis that subepithelial OO muscle defects are a mild manifestation of the lip portion of the CL/P phenotype. Given that subepithelial OO muscle defects are relatively straightforward to identify via ultrasound, such defects show great promise for providing more accurate recurrence risk estimates to relatives in cleft families. Furthermore, inclusion of OO defects in the CL/P phenotypic spectrum should improve the power of genetic studies.
Potential role of PC‐1 expression and pyrophosphate elaboration in the molecular etiology of the FGFR‐associated craniosynostosis syndromes
Authors: Hatch NE 
Published: June 2007

Structured AbstractAuthor –  Hatch NEBackground –  Fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) signaling is associated with the aberrant mineralization phenotype of the craniosynostosis syndromes. One critical aspect of mineralization involves the elaboration and transport of pyrophosphate into the extracellular matrix with subsequent enzymatic hydrolysis into phosphate. We have previously shown that FGF2 up‐regulates expression of the pyrophosphate generating enzyme, PC‐1, and the pyrophosphate channel, ANK, while down‐regulating expression of the pyrophosphate hydrolyzing enzyme, tissue non‐specific alkaline phosphatase in pre‐osteoblastic, MC3T3E1(C4) cells. These results suggest that FGF/FGFR signaling may affect mineralization via changes in the elaboration and metabolism of pyrophosphate.Objectives –  We are currently conducting experiments towards a more systematic analysis of PC‐1 expression in osteoblastic cells, in order to more clearly elucidate the significance of pyrophosphate elaboration in the process of normal bone mineralization and in the molecular etiology of the FGFR‐associated craniosynostosis syndromes.Design –  Towards this goal we have constructed a PC‐1 gene promoter/firefly luciferase reporter construct, in order to more directly investigate the regulation of PC‐1 by FGF/FGFR signaling in osteoblastic and non‐osteoblastic cells.Results and Conclusions –  Preliminary results confirm that FGF/FGFR signaling, either via treatment with FGF2 or via expression of a Crouzon syndrome‐associated mutant FGFR2, induces PC‐1 promoter activity in osteoblastic cells in culture. This appears to be a cell type specific phenomenon. These results suggest that the expression of PC‐1 downstream of FGF signaling is an integral aspect of osteoblastic function, and that pyrophosphate elaboration may play a significant role in the pathology of craniosynostosis.
Greening of the Tooth–Amalgam Interface during Extended 10% Carbamide Peroxide Bleaching of Tetracycline‐Stained Teeth: A Case Report
Authors: HAYWOOD VAN B. 
Published: June 2007

ABSTRACTAt‐home bleaching with 10% carbamide peroxide in a custom‐fitted tray has been shown to have some minor effects on certain brands of amalgam, pertaining to mercury release, but generally, effects on amalgam are not considered clinically significant. However, in this case report, a greening of the tooth structure in certain areas immediately adjacent to amalgam restorations in the maxillary and mandibular first molars occurred during tooth whitening. Other amalgam restorations in mandibular and maxillary second molars in the same mouth did not demonstrate any green discoloration of the teeth. Upon removal of the affected amalgam restorations, recurrent decay was present in the areas of tooth greening but not in other areas adjacent to the restoration. The teeth were restored with posterior composite restorations. Whether the green discoloration was a result of some loss of material from a particular brand of amalgam, indicating leakage, or indicative of original or recurrent tooth decay is unclear in this single‐patient situation. Other patients in the same study did not demonstrate this occurrence. Dentists should be ready to replace amalgam restorations should this green discoloration in adjacent tooth structure occur during bleaching, in case decay is present.CLINICAL SIGNIFICANCEThe unusual discoloration cited suggests that amalgam restorations in potentially esthetic areas, including the lingual of anterior teeth, should be replaced prior to bleaching, to avoid the problem of difficult stain removal or translucency allowing restoration visibility following bleaching.
Esthetic Correction of Gingival Recession Using a Modified Tunnel Technique and an Acellular Dermal Connective Tissue Allograft
Authors: MAHN DOUGLAS H. 
Published: June 2007

ABSTRACTEsthetic correction of gingival recession is an important goal of periodontal therapy. This article describes a surgical technique that combines a modified tunnel technique and an acellular dermal connective tissue allograft. With the aid of vertical incisions, a tunnel is created under the buccal mucosa of the affected tooth. These incisions enable easy access for graft placement and create mobility for gingival coronal positioning. The use of an acellular dermal connective tissue allograft eliminates the need for a surgical palatal donor site. This minimizes postsurgical complications.CLINICAL SIGNIFICANCEThe combination of a modified tunnel technique and an acellular dermal connective tissue allograft permits esthetic root coverage in a manner that reduces postsurgical complications.
Critical Appraisal
Authors: Demke Richard , Ewoldsen Nels , Swift Edward J. 
Published: June 2007

Many dentists still view zinc phosphate as the “gold standard” for luting cast and porcelain‐fused‐to‐metal restorations. Introduced in 1879, zinc phosphate cement has withstood the test of time and gained a reputation for reliability despite its nonadhesive qualities and association with postcementation sensitivity when handled improperly. Hewer classes of luting cements have been introduced, including polycarboxylate, glass ionomer, resin‐reinforced (resin‐modified) glass ionomer, and resin composite. Several of these materials have advantages over zinc phosphate, including adhesion to alloys and tooth structure, fluoride release, and improved physical properties. Conversely, they also exhibit some disadvantages, such as higher cost, complex handling requirements, and adhesive qualities that can make retrieval of castings impossible. This “Critical Appraisal” reviews recent articles dealing with newer luting cements in an effort to give readers some assistance in their selection and use.Two publications address the effect of handling and manipulation variables on the physical properties of various cements. Another in vitro investigation highlights the margin sealing effect of resin‐modified glass ionomer composite (GIC) with and without saliva contamination. Finally, a large retrospective study reports clinical outcomes of anterior and posterior alumina core all‐ceramic crowns luted with a resin‐modified GIC. The significance of each publication is discussed below.
Higher‐Concentration Carbamide Peroxide Effects on Surface Roughness of Composites
Authors: LANGSTEN ROBERT E. , DUNN WILLIAM J. , HARTUP GRANT R. , MURCHISON DAVID F. 
Published: June 2007

ABSTRACT Background: Ten percent carbamide peroxide has been used extensively within the dental profession for the purpose of bleaching teeth. Although this method has been successful, the use of higher‐concentration carbamide peroxides (20–35%) for home bleaching has increased substantially in the past few years. The purpose of this study was to evaluate changes in surface roughness of a hybrid and a microfilled composite after exposure to bleaching agents containing higher concentrations of carbamide peroxide. Materials and Methods: Sixty‐eight circular, resin‐based composite specimens (8 mm ± 2 mm) were prepared against a Mylar surface. Half of the specimens were fabricated from a hybrid composite material and the other half with a microfilled composite. Specimens were polished with aluminum oxide finishing disks, divided into four groups, and then exposed either to 20% carbamide peroxide for 3 hours per day for 14 days or to 35% carbamide peroxide for 1 hour per day for 14 days. The mean surface roughness (Ra) was determined for each specimen before and after exposure to bleaching agents, using mechanical profilometry. Data were analyzed by two‐way analysis of variance (ANOVA) for differences between composite type, carbamide peroxide concentrations, and interaction of the two factors with respect to average surface roughness. All data analysis was performed at α= 0.05. Results: Mean change from baseline of surface roughness (Ra) of microfilled composite and 20% carbamide peroxide was −0.03 μm ± 0.10 um; microfilled composite and 35% carbamide peroxide: 0.01 pm ± 0.02 um; hybrid composite and 20% carbamide peroxide: −0.43 um ± 0.91 um; hybrid composite and 35% carbamide peroxide: −0.19 pm ± 0.43 pm. Surface roughness of hybrid or microfilled composite did not change significantly from baseline with either concentration of carbamide peroxide (p = .300).
Evaluation of Microleakage in Cervical Margins of Various Posterior Restorative Systems
Authors: DE CASTRO ANA KARINA BARBIERI BEDRAN , PIMENTA LUIZ ANDRÉ FREIRE , AMARAL CRISTIANE MARIOTE , AMBROSANO GLÁUCIA MARIA BONI 
Published: June 2007

ABSTRACT Purpose: The purpose of this in vitro study was to evaluate the microleakage and dye penetration patterns of various restorative systems in the cervical margins of Class II cavities using the dye penetration technique. Materials and Methods: Ninety bovine incisors were selected and part of the crown was sectioned producing a standardized occlusogingival margin of 4 mm. Standardized Class II box cavities were designed on the mesial (MO) and distal (OD) surfaces with the gingival margin in dentin. The cavities were randomly divided into six groups (n = 30): group 1 (control), Etch & Prime 3.0 (Degussa AG) + Definite (Degussa AG); group 2, Prime & Bond NT (Dentsply De Trey) + Definite; group 3, Etch & Prime 3.0 + flowable composite resin Wave (SDI) + Definite; group 4 (control), Prime & Bond NT + TPH Spectrum (Denstply De Trey); group 5, Etch & Prime 3.0 + TPH Spectrum; group 6, Prime & Bond NT + Wave + TPH Spectrum. After they were finished and polished, the specimens were subjected to 1500 thermal cycles in baths of 5°± 2°C and 55°± 2°C with 60 seconds of dwell time for each bath. After the thermocycling, the specimens were sealed with acid‐resistant varnish, leaving a 1‐mm window around the cervical margin interface, and immersed in 2% methylene blue buffered solution for 4 hours. Then the specimens were sectioned longitudinally in half and qualitatively evaluated under stereomicroscopy at 45 times magnification, using ranked scores for the dentin cervical margin (0–4). The dye penetration pattern (adhesive or dentinal) was also evaluated. The data were subjected to a reproducibility kappa test, and the mean of the three examiners' scores was analyzed by the Kruskal‐Wallis nonparametric test and a multiple comparison nonparametric test. Fisher's exact test was used to evaluate the dye penetration pattern. Results: The rank sums of the groups were expressed in decreasing order: group 4, 67.23a; group 3, 72.58ab; group 6, 78.43ab; group 5, 93.19bc; group 2, 112.97c; group 1, 113.52c. (Statistically significant differences are expressed by different superscript letters.) The results indicate that none of the systems used in this study was able to impede microleakage, and that the use of a flowable resin decreases the values of leakage only for Definite composite resin. The dye penetration pattern for the groups that used Prime & Bond NT was predominantly dentinal, whereas the pattern for Etch & Prime 3.0 groups was adhesive.
Diagnosis and Management of Maxillary Incisors Affected by Incisal Wear: An Interdisciplinary Case Report
Authors: BERNARDON JUSSARA KARINA , MAIA ELAINE A. VILELA , CARDOSO ANTÔNIO CARLOS , DE ARAÚJO EDSON MEDEIROS , MONTEIRO SYLVIO 
Published: June 2007

ABSTRACTIn the attempt to restore anterior teeth affected by erosion and bruxism, many clinicians have been frustrated with the constant restorative failures. Frequently, these failures are attributed to the restorative materials employed, especially in cases in which composite resins are used. However, some flaws of the restorations are related to the oversight of occlusal principles. The purpose of this article is to discuss the etiology, signs, and symptoms of incisal wear, with special attention to that caused by bruxism and chemical erosion. Relatively simple management techniques (e.g., occlusal adjustment, adhesive restorations) are proposed, and the diagnosis and management of a representative clinical case is presented.
Capping the Inflamed Pulp under Different Clinical Conditions
Authors: TROPE MARTIN , McDOUGAL ROGER , LEVIN LINDA , MAY KENNETH N. , SWIFT EDWARD J. 
Published: June 2007

ABSTRACT Background: A great deal of controversy exists regarding the reliability of capping the inflamed pulp. In particular, the use of calcium hydroxide as a capping agent has come into question. In this study, hard tissue barrier formation after inflamed pulps were capped directly or after partial pulpotomy was compared with calcium hydroxide or bonded resin and with no additional seal or an IRM surface seal. Seventy teeth in five dogs were used. Ten untreated teeth were used as negative controls. In 60 teeth, pulpal inflammation was induced by preparing a cavity close to the pulp and sealing a cotton pellet soaked in plaque in it for 1 to 2 weeks. The cavities were then re‐entered and extended to expose the pulps. Materials and Methods: In half the teeth (n = 30) a partial pulpotomy was performed and in the other half (n = 30) pulpal treatment was performed on the superficial exposed pulp. Both pulpal treatment groups received the same restorative procedures: (1) calcium hydroxide + amalgam + IRM surface seal; (2) OptiBond Solo, Prodigy with IRM surface seal; or (3) OptiBond Solo, Prodigy without IRM surface seal. The presence, absence, and quality of a hard tissue barrier were evaluated histologically. Results: The calcium hydroxide groups were statistically superior to all other groups. The IRM surface seal resulted in significantly better healing. Although there was no statistically significant difference between direct pulp capping and partial pulpotomy with the numbers in this study, power statistics indicated that in clinical practice a partial pulpotomy would be preferable.
In Vitro Wear Simulation Measurements of Composite versus Resin‐Modified Glass Ionomer Luting Cements for All‐Ceramic Restorations
Authors: BRAGA ROBKRTO R. , CONDON JOHN R. , FERRACANK JACK L. 
Published: June 2007

ABSTRACT Background: Although composite cements are generally indicated for cementation of all‐ceramic restorations, some manufacturers of dental cements propose that resin‐modified glass ionomers (RMGIs) may be used for cementation of high‐strength ceramic restorations. Purpose: This study was undertaken to compare the in vitro abrasion and attrition wear of two dual‐cure cements (in dual‐cure and self‐cure modes) and two RMGI cements when placed between ceramic and enamel to simulate the margin of a restoration. Methods: Rectangular fragments of pressed ceramic (Empress 2) were cemented between the halves of bovine incisors sectioned mesiodistally, using one of the following materials: RelyX ARC, Variolink II, RelyX Luting, or ProTec CEM. The two resin cements were tested in dual‐cure and self‐cure modes. A three‐body wear test was performed in the new Oregon Health Sciences University (OHSU) oral wear simulator (100,000 cycles; abrasion load: 20 N; attrition load: 90 N). Degree of conversion of resin cements was determined by Fourier transform infrared spectroscopy. Results were analyzed by analysis of variance and Tukey's test (p = .05). Epoxy replicas of wear specimens were observed in the scanning electron microscope. Results: No significant differences in abrasion wear (RelyX ARC dual‐cure: 11± 4.4 urn; RelyX ARC self‐cure: 17 ± 7.0 urn; Variolink dual‐cure: 14 ± 8.6 urn; Variolink self‐cure: 23 ± 10.7 um) or attrition wear (RelyX ARC dual‐cure: 18 ± 6.4 um; RelyX ARC self‐cure: 31 ± 4.5 um; Variolink dual‐cure: 32 ± 6.8 um; Variolink self‐cure: 39 ± 15.9 pm) were found between activation modes of the resin cements. ProTec CEM (32 ± 8.7 um) showed abrasion similar to that of Variolink II and RelyX ARC self‐cure. Resin‐modified glass ionomers showed more attrition wear than the resin cements (ProTec CEM: 62 ± 13.0 um; RelyX Luting: 69 ± 7.1 um). RelyX ARC showed a similar degree of conversion for both activation modes (dual‐cure: 70 ± 4.3%; self‐cure: 68 ± 1.2%), but Variolink II had a higher degree of conversion in dual‐cure mode (67 ± 0.5% vs 60 ± 1.0%). Cement wear was accompanied by marginal breakdown and increased surface roughness of enamel and ceramic. Conclusions: The activation mode of resin cements did not influence their wear resistance. The RMGIs underwent higher attrition wear than the resin cements.CLINICAL SIGNIFICANCEIncreased submargination associated with marginal breakdown and increased roughness of the surrounding structures may be expected when ceramic inlays are cemented with resin‐modified glass ionomers.