Effect of microwave disinfection on the surface roughness of three denture base resins after tooth brushing

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

Assessment of the Ability to Relate Anterior Tooth Form and Arrangement to Gender

Purpose: This study evaluated the assumption that there are morphological differences between the natural anterior dentition of men and women. The goal of the study was to determine the gender of patients based on the appearance of the anterior teeth in photographs. Materials and Methods: Laymen and observers from different specialties were asked to determine the gender of individuals based on the shape and arrangement of anterior teeth. Forty anterior dentition photographs of dental students of both genders (20 women, 20 men) between 18 and 26 years old were selected, coded, and randomly arranged in an album. The albums were delivered to five groups of observers: general practitioners (recently graduated dentists), prosthodontists, orthodontists, restorative dentists (specialists in cosmetic and restorative dentistry), and laymen (control group). The observers evaluated the photographs twice at 1-week intervals. Results: The average correctly identified values in women and men were 57.6% and 58.8%, respectively. There was no statistical difference between observers and between each group of professionals and the laymen group (p > 0.05). An intraobserver agreement was not observed between the evaluations (kappa =-0.01). Conclusion: The results of this limited study indicated that it was not possible to differentiate gender by viewing photographs of anterior teeth.

The use of calcium hydroxide and mineral trioxide aggregate on apexification of a replanted tooth: a case report

To report the outcome of the endodontic treatment of a reimplanted central maxillary incisor with open apex after 8 years and 7 months of follow-up.This case report presents the treatment of a right central maxillary incisor of an 8-year old white male patient with history of traumatic avulsion and immediate replantation. The endodontic therapy consisted of periodical changes of calcium hydroxide dressing and a definitive root canal filling with mineral trioxide aggregate (MTA). The treatment was successful without pathologies up to 7 years of follow-up. After the institution of orthodontic treatment a localized and late root resorption was noticed at the last radiographic examination (8 years and 7 months postoperative follow-up). Moreover, the use of MTA promoted a mild crown grey discoloration.

Ability of Gutta-Percha and Resilon to Fill Simulated Lateral Canals by Using the Obtura II System

Introduction: The aim of this study was to evaluate the ability of Resilon (Resilon Research, LLC, North Branford, CT) and 2 types of gutta-percha to fill simulated lateral canals when using the Obtura II system (Model 823-700; Obtura Spartan, Fenton, MO). Methods: Forty-five human single-rooted teeth were selected and subjected to root canal preparation. After that, simulated lateral canals were made at 2, 5, and 8 mm from the working length (WL). The specimens were divided into 3 groups (n = 15) according to the filling material used: Obtura Flow 150 gutta-percha (Obtura flow), Odous Endo Flow gutta-percha (Odous; Odous de Deus Ind e Corn. Ltda Belo Horizonte, MG, Brazil), and Resilon pellets (Resilon). Root canals were filled using the Obtura II system with the tip inserted to 3 mm from the WL. No sealer was used for root canal obturation. Specimens were subjected to a tooth decalcification and clearing method, and filling of the lateral canals was analyzed by digital radiography and photographs. The measurement of lateral canal filling was done using Image Tool software (UTHSCSA Image Tool for Windows version 3.0, San Antonio, TX). Data were statistically analyzed with the Kruskal-Wallis test at 5% significance. Results: All materials showed an ability to penetrate into the simulated lateral canals, with a minimum percentage of 73% in all thirds of the root canal. Conclusions: It was concluded that gutta-percha and Resilon are solid core materials with a lateral canal filling ability when used with the Obtura II system. (J Endod 2012;38:676-679)

Length-weight relationships for 20 species collected in the Jurumirim reservoir (Paranapanema Basin, Brazil)

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

Description of the Larvae of Tapinoma melanocephalum (Hymenoptera: Formicidae)

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

Manipulation of Rest Period Length Induces Different Causes of Fatigue in Vertical Jumping

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

THE INFLUENCE of RESTING PERIOD LENGTH on JUMPING PERFORMANCE

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Aspects of the reproductive biology of the shortfin mako, Isurus oxyrinchus (Elasmobranchii Lamnidae), in the Southeastern region of Brazil

Quatro úteros provenientes de quatro fêmeas prenhas e dois indivíduos recém-nascidos de anequim, Isurus oxyrinchus, foram coletados na região Sudeste do Brasil durante os meses de setembro a novembro de 1993 e 1994. Todos os embriões estavam bem desenvolvidos, próximos ao estágio de nascimento, apresentando a dentição e órgãos internos bastante desenvolvidos. O comprimento total desses embriões variou entre 64,5 e 72,0 cm, e o maior número de embriões observado no interior de uma única fêmea foi 20. As observações aqui realizadas confirmam a oofagia como forma de nutrição dos embriões dessa espécie e sua periodicidade. A presença de dentes no estômago dos embriões sugere que a substituição dos dentes se inicia na fase uterina.

The effect of chain length on the melting temperature and size of dialkyldimethylammonium bromide vesicles

Differential scanning calorimetry (DSc) and dynamic light scattering (DLS) were used to obtain the gel to liquid-crystalline phase transition temperature (T-m) and the apparent hydrodynamic radius (R-h) of spontaneously formed cationic vesicles of dialkyldimethylammonium bromide salts (CnH2n+1)(2)(CH3)(2)N+center dot Br-, with varying chain lengths. The preparation of cationic vesicles from aqueous solution of these surfactants, for n = 12, 14, 16 and 18 (DDAB, DTDAB, DHDAB and DODAB, respectively), requires the knowledge of the surfactant gel to liquid-crystalline phase transition temperature, or melting temperature (T-m) since below this temperature these surfactants are poorly or not soluble in water. That series of cationic surfactants has been widely investigated as vesicle-forming surfactants, although C-12 and C-18, DDAB and DODAB are by far the most investigated from this series. The dependence of T-m of these surfactants on the number n of carbons in the surfactant tails is reported. The T-m obtained by DSC increases non-linearly with n, and the vesicle apparent radius R-h is about the same for DHDAB and DODAB, but much smaller for DDAB. (c) 2006 Elsevier B.V.. All rights reserved.

Structural resistance in immature teeth using root reinforcements in vitro

The purpose of this study was to evaluate in vitro the efficacy of root reinforcements by light-cured composite resin or zirconium fiber post in simulated immature non-vital teeth. Fifty-six bovine incisors teeth were used for this study. The crown of each tooth was removed in the medium third to obtain a standard length of 30 mm. The specimens were divided into four groups (n = 14): G1) the root canals were instrumented and enlarged to simulate immature non-vital teeth and were reinforced with a light-cured composite resin using a translucent curing post (Luminex system); (G2) the specimens were instrumented, enlarged and they received root reinforcement with zirconium fiber post; G3 (positive control): they received similar treatment to the G1 and G2 groups, but did not receive root reinforcement; G4 (negative control): the roots were not weakened and did not receive reinforcement. Every tooth was submitted to compressive force using an Instron testing machine with an angle of 45&DEG; at a speed of 1 mm min(-1) until the fracture. The results showed a markedly increased resistance to fracture in the G1 and G2 (122.38 and 122.08 kgf, respectively). Among the results of G1 and G2 there was not any significant difference (P > 0.05) but they were significantly different from the control groups (P < 0.05). The conclusion is that the use of root reinforcements with zirconiun fiber post or composite resin can increase significantly the structural resistance of the weakened teeth, decreasing the risk of the fracture.

Root surface treatment using diode laser in delayed tooth replantation: radiographic and histomorphometric analyses in rats

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

Morphology and bacterial colonisation of tooth/ceramic restoration interface after different cement excess removal techniques

Objectives: To evaluate the influence of different protocols for resin cement removal during cementation on biofilm formation.Methods: Twenty-eight ceramic blocks, which were injected under pressure, were placed over enamel blocks obtained from freshly extracted bovine incisors. The ceramic blocks were cemented to the enamel blocks using a dual-cured resin cement and the excess resin was removed according to the experimental group: TS: Teflon spatula; BR: brush; BR+: brush and polishing; SB+: scalpel blade and polishing. After autoclaving, the samples were colonised by incubation in a sucrose broth suspension standardised with Streptococcus mutans in microaerophilic stove. Specimens were quantitatively analysed for bacterial adherence at the adhesive interface using confocal laser scanning microscopy and counting the colony forming units, and qualitatively analysed using SEM. The roughness (Ra/Rz/RSm) was also analysed. Data were analysed by 1-way ANOVA and Tukey's test (5%).Results: The roughness values ranged from 0.96 to 1.69 mu m for Ra (p > 0.05), from 11.59 to 22.80 mu m for Rz (p = 0.02 < 0.05) and from 293.2 to 534.3 mu m for RSm (p = 0.00). Bacterial adhesion varied between 1,974,000 and 2,814,000 CFU/ml (p = 0.00). Biofilm mean thickness ranged from 0.477 and 0.556 mu m (p > 0.05), whilst the biovolume values were between 0.388 and 0.547 mu m(3)/mu m(2) (p = 0.04). Lower values for roughness, bacterial adhesion, biofilm thickness and biovolume were found with BR, whilst TS presented the highest values for most of the parameters. SEM images confirmed the quantitative values.Conclusions: The restoration margin morphology and interface roughness affects bacterial accumulation. The brush technique promoted less bacterial colonisation at the adhesive interface than did the other removal methods.Clinical significance: The brush technique seems to be a good option for removing the excess resin cement after adhesive cementation in clinical practice, as indicated by its better results with lower bacterial colonisation. (C) 2012 Elsevier Ltd. All rights reserved.

Analysis of Tooth Enamel After Excessive Bleaching: A Study Using Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy

This study assessed alterations on bovine enamel after excessive bleaching. Coronal portions of bovine teeth (n = 30) were sectioned and divided into three groups (n = 10 per group). The coronal parts were further cut incisocervically into two halves. While one half received no bleaching (control), the other half was subjected to either one (group 1), three (group 2), or five bleaching sessions (group 3) with 35% hydrogen peroxide. The enamel surfaces were then analyzed using scanning electron microscopy and energy dispersive x-ray spectroscopy (EDS). Fxcessive bleaching affected the surface morphology and chemistry of the bovine enamel. EDS analysis showed the highest decrease in calcium ion percentages in groups 2 and 3 when compared to their nonbleached halves. Oxygen and phosphorus percentages were comparable on both the control and bleached enamel, regardless of the number of bleaching sessions. Consecutive bleaching sessions with 35% hydrogen peroxide may lead to morphologic and specific elemental changes when performed in a short period of time. Calcium ion percentages may decrease when this bleaching agent is used for more than one session. Int J Prosthodontics 2010;23:29-32.