Proteins, Pathogens, and Failure at the Composite-Tooth Interface

In the United States, composites accounted for nearly 70% of the 173.2 million composite and amalgam restorations placed in 2006 (Kingman et al., 2012), and it is likely that the use of composite will continue to increase as dentists phase out dental amalgam. This trend is not, however, without consequences. The failure rate of composite restorations is double that of amalgam (Ferracane, 2013). Composite restorations accumulate more biofilm, experience more secondary decay, and require more frequent replacement. In vivo biodegradation of the adhesive bond at the composite-tooth interface is a major contributor to the cascade of events leading to restoration failure. Binding by proteins, particularly gp340, from the salivary pellicle leads to biofilm attachment, which accelerates degradation of the interfacial bond and demineralization of the tooth by recruiting the pioneer bacterium Streptococcus mutans to the surface. Bacterial production of lactic acid lowers the pH of the oral microenvironment, erodes hydroxyapatite in enamel and dentin, and promotes hydrolysis of the adhesive. Secreted esterases further hydrolyze the adhesive polymer, exposing the soft underlying collagenous dentinal matrix and allowing further infiltration by the pathogenic biofilm. Manifold approaches are being pursued to increase the longevity of composite dental restorations based on the major contributing factors responsible for degradation. The key material and biological components and the interactions involved in the destructive processes, including recent advances in understanding the structural and molecular basis of biofilm recruitment, are described in this review. Innovative strategies to mitigate these pathogenic effects and slow deterioration are discussed.

Análise da qualidade de vida de pacientes com a doença de Charcot-Marie-Tooth tipo 1A

A doença de Charcot-Marie-Tooth (CMT) é a mais freqüente das neuropatias hereditárias, mas a sua história natural é pouco conhecida. Apesar da maioria dos pacientes apresentarem uma evolução com características mais “benignas”, é associado à doença com um comprometimento funcional, o que pode ser acompanhado de limitações e incapacitações. O presente estudo teve como objetivo avaliar a qualidade de vida de pacientes afetados pela CMT1A. Considerando que a qualidade de vida pode sofrer influência de variáveis sócio-culturais, um estudo neste contexto mostra-se oportuno. Nenhum estudo de nosso conhecimento realizou tal avaliação no contexto brasileiro. Fizeram parte deste estudo pacientes com CMT decorrente da duplicação 17p11.2-p12 (CMT1A) que foram avaliados quanto ao comprometimento funcional por meio da aplicação do SF-36. Esse questionário é utilizado internacionalmente para aferir a qualidade de vida dos indivíduos. Os resultados obtidos foram submetidos à análise estatística. Como resultados não se observaram associações entre o gênero e os domínios avaliados para a qualidade de vida. Os dados obtidos revelaram que a qualidade de vida dos pacientes com CMT1A se mostrou comprometida principalmente quanto aos seus Aspectos Sociais (p = 0,02) e Aspectos emocionais (p = 0,04). Adicionalmente, houve uma tendência ao comprometimento da Capacidade Funcional (p = 0,08), sendo que os outros índices de avaliação de comprometimento físico se mostraram preservados. A presença ou ausência de ocupação parece influenciar os Aspectos Sociais apresentando uma tendência de diferença significativa (p = 0,07), possuindo o grupo com ocupação valores superiores. Apesar da CMT1A apresentar piora clínica ao longo dos anos, a idade mais avançada não implicou em uma pior percepção da qualidade de vida no grupo de pacientes estudados no presente trabalho... (Resumo completo, clicar acesso eletrônico abaixo)

Controlling mechanical undesirable side effects with a tooth indicated for extraction: free anchorage

This manuscript describes the use of a tooth indicated for extraction due
to orthodontic reasons as an anchorage aid to receive undesirable side effects caused by orthodontic uprighting of a contralateral molar tooth. The mandibular right second molar was mesially tipped as a result of loss of the adjacent first molar. Since the treatment plan involved extraction of the mandibular left first premolar, undesirable side effects associated with the molar uprighting movement were transferred to this tooth. Once the second molar was vertical, the premolar was extracted and the treatment continued. The results suggest that treatment time can be reduced if undesirable orthodontic mechanical side effects can be directed to a tooth whose extraction is indicated.

Correlation between pH and surface structural changes on human enamel submitted to different tooth whitening agents

The intense valuation of an esthetic pleasant smile guided the dentistry to bleached tooth due the popularity of whitening treatments. The consequence of it is an increasing interest in searching the effect of peroxides in hard dental tissues. The aim of this work was to analyze qualitatively in vitro the human enamel after three different bleaching treatments: Opalescence PF 10%, White Class 7.5% and Opalescence Xtra Boost 38%, correlating the structural changes in the surface of the enamel with its respective pH. A total of 40 sound human pre-molars were randomly divided into four groups of 10 elements, which had been immersed in artificial saliva during all the experiment. Bleaching protocols followed the recommendations of the respective manufacturers. Each bleached sample and control group were submitted to a scanning electronic microscopy analysis and compared with one another. Bleaching agents used in this experiment had modified the morphologic aspect of the surface of the dental enamel; however, it did not have correlation between the degrees of severity of the alterations and pH. There is a correlation between hydrogen peroxide concentration and changes in the enamel, where G4 showed more severe alterations, followed for G3 and G2.

Effect of two formulations of 10% sodium ascorbate on fracture resistance of endodontically treated tooth submitted to dental bleaching with hydrogen peroxide associated titanium dioxide nanoparticles

Purpose: This study evaluated the effect of 10% sodium ascorbate (10SA), in gel (10SAg) or aqueous solution (10SAs) formulations, on fracture resistance of endodontically treated tooth submitted to dental bleaching procedures with 15% hydrogen peroxide associated with titanium dioxide (15HP-TiO2) nanoparticles and photoactivated by LED-laser. Material and methods: Forty maxillary premolars were endodontically-treated and embedded in acrylic resin up to the cement-enamel junction. The specimens were divided into four groups (n=10): G1 (negative control): no bleaching, coronal access restored with composite resin; G2 (positive control): three dental bleaching sessions using 15HP-TiO2 and LED-laser photoactivation and restored with composite resin (positive control); G3 (10SAg): similar procedures to G2, but applied 10SA, in gel formulation, for 24 hours before restoration; G4 (10SAs): similar procedures to G3, but applied 10SA, in aqueous solution formulation. The 15HP-TiO2 was applied on buccal and lingual surfaces of the crown tooth and inside the pulp chamber and photoactivated by LED-laser. Between each bleaching session, the teeth were maintained in artificial saliva, at 37oC, for 7 days. In sequence, the teeth were submitted to fracture resistance testing using an eletromechanical machine test. The data was analyzed using Kruskal Wallis test (p = 0.05) Results: There are no differences significant among the groups in relation to fracture resistance of endodontically treated teeth (p>0.05). Conclusions: The use of 10% sodium ascorbate, in gel or aqueous solution formulations, did not interfered on the fracture resistance teeth after dental bleaching using 15HP-TiO2 and LED-laser photoactivation.

Filling of simulated lateral canals with gutta percha or resilon when using thermomechanical compaction

Aims: To evaluate the filling of simulated lateral canals with gutta-percha or Resilon when using thermomechanical compaction. Setting and Design: Forty-five human single-rooted teeth were subjected to tooth decalcification and clearing. Materials and Methods: After root canal preparation, artificial lateral canals were made at 2, 5, and 8 mm from the working length (WL), corresponding to the apical, middle, and cervical thirds, respectively. The specimens were divided (n = 15) according to the filling material: Dentsply gutta-percha (GD), Odous gutta-percha (GO), and Resilon cones (RE). Root canals were obturated by thermomechanical compaction using a #45 compactor and no sealer. Lateral canals were analyzed by digital radiography and digital images after tooth decalcification and clearing using the Image Tool software. Statistical Analysis Used: Data were subjected to the Kruskal-Wallis and Dunn tests at 5% significance. Results: In the coronal third, RE and GO presented more filling ability than GD (P < 0.05). In the middle and apical thirds, RE presented the best results. Conclusions: Resilon demonstrated filling ability as material for root canal obturation by using thermomechanical compaction.

Análise dos troncos radiculares, abertura da raízes e projeções cervicais de esmalte de furcas de molares superiores e inferiores: Estudo in vitro

Periodontal treatment of teeth with furcation lesions often have unpredictable results due to several factors that may hinder therapy or influence the progress of periodontal disease. Of these, the length of the root trunk may contribute to the early injury of the furcations or even cause complications for the application of the treatment; the opening of the roots can guide the type of treatment to be instituted and cervical enamel projections may hinder the instrumentation of the region or even act as a retention plate niche. Thus, the purpose of this study was measured using a digital caliper, root logs database 400 molar both the 1st and the 2nd and both upper and lower as well as analyze using appropriate index type projection cervical enamel and through appropriate classification the opening of the roots in order to guide the diagnosis and treatment plan. We conclude that there is variation in measures of root trunk between the faces of the teeth examined and that greater cervical enamel projection (ECP) correlates with a decrease in the length of the root trunk in the sample evaluated as the first molars have higher occurrence of roots with a degree of opening larger than the second molars.

Comparative study on direct and indirect bracket bonding techniques regarding time length and bracket detachment

OBJECTIVE: The aim of this study was to assess the time spent for direct (DBB - direct bracket bonding) and indirect (IBB - indirect bracket bonding) bracket bonding techniques. The time length of laboratorial (IBB) and clinical steps (DBB and IBB) as well as the prevalence of loose bracket after a 24-week follow-up were evaluated. METHODS: Seventeen patients (7 men and 10 women) with a mean age of 21 years, requiring orthodontic treatment were selected for this study. A total of 304 brackets were used (151 DBB and 153 IBB). The same bracket type and bonding material were used in both groups. Data were submitted to statistical analysis by Wilcoxon non-parametric test at 5% level of significance. RESULTS: Considering the total time length, the IBB technique was more time-consuming than the DBB (p < 0.001). However, considering only the clinical phase, the IBB took less time than the DBB (p < 0.001). There was no significant difference (p = 0.910) for the time spent during laboratorial positioning of the brackets and clinical session for IBB in comparison to the clinical procedure for DBB. Additionally, no difference was found as for the prevalence of loose bracket between both groups. CONCLUSION: the IBB can be suggested as a valid clinical procedure since the clinical session was faster and the total time spent for laboratorial positioning of the brackets and clinical procedure was similar to that of DBB. In addition, both approaches resulted in similar frequency of loose bracket.

Filling of simulated lateral canals with gutta-percha or thermoplastic polymer by warm vertical compaction

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The length of the dry season may be associated with leaf scleromorphism in cerrado plants

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise histométrica do processo de reparo do reimplante dentário submetidos à terapia com laser de baixa intensidade: estudo em ratos

Pós-graduação em Odontologia - FOA

Vitamin D serum levels are associated with handgrip strength but not with muscle mass or length of hospital stay after hip fracture

Objectives: The aim of this study was to evaluate the association between serum levels of 25(OH) vitamin D-3 with midupper arm muscle circumference (MUAMC), handgrip strength and length of hospital stay (LOS) after hip fracture.Methods: In total, 102 consecutive patients with hip fracture over the age of 65 were admitted to the orthopedic unit and prospectively evaluated. All of the patients were treated according to specific protocols depending on the type of fracture. Anthropometric measurements and handgrip strength were performed, and blood samples were taken for serum biochemistry and 25(OH) vitamin D-3 analysis within the first 72 h of admission. All of the patients were followed during their hospital stay, and the length of stay was recorded.Results: Of the patients, two were excluded because of pathologic fractures. In total, 100 patients with a mean age of 80 +/- 7 y were included in the analysis. Among these patients, 73% were female, and 37% had vitamin D deficiency. The median LOS was 7 (5-11) d. Patients with vitamin D deficiency had lower handgrip strength in univariate analysis. In the multiple linear regression analysis with robust standard error, serum vitamin D levels adjusted by age and sex were associated with handgrip strength but not with MUAMC and LOS after hip fracture.Conclusions: In conclusion, vitamin D serum levels were associated with handgrip strength but not with muscle mass or length of hospital stay after hip fracture. (C) 2015 Elsevier Inc. All rights reserved.

Effect of alendronate sodium on tooth movement in ovariectomized rats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Length-weight relationship of 37 fish species from the Taquari River (Paranapanema Basin, Brazil)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)