Anatomical evaluation of the cervical vertebrae of Wistar rats by means of digital radiographs and its correlation with the maturation stages of human cervical vertebrae

INTRODUCTION: Biological age is an important parameter for growth and development assessment. It can be evaluated through the observation of radiographic changes in skeletal maturation of cervical vertebrae. OBJECTIVE: This study aims to: a) verify if there is correlation between growth curve and the stages of bone age of animals used in laboratories, by evaluating radiographs of the cervical vertebrae; b) correlate these stages with their correspondents in humans. METHODS: 35 Wistar rats were evaluated for a period of 160 days, starting at day 22nd (weaning), with cross sections for periodic weighing, length measurement and digital radiography. Radiographs of the cervical vertebrae (C2 and C3) were measured by means of a computer program (Radio IMP). Data were submitted to statistical analysis (ANOVA) and Pearson correlation. RESULTS: Growth spurt was characterized by fast increasing in weight and length. Through ANOVA, differences were observed in the cervical measurements between days 22, 97, 127, 157, 187 and 217 (p <0.001). A high correlation was found between increasing in body length and weight, as well as in cervical vertebrae height (r = 0.86). Increments in concavities of vertebrae were also observed, similar to humans. CONCLUSIONS: There is correlation between body growth and maturation of cervical vertebrae in rats. Despite the continuous development of concavities, it was not possible to clearly identify the 5/6 stages as in studies of cervical vertebrae maturation in humans.

Análise através do método dos elementos finitos das tensões desenvolvidas no reborbo alveolar sob as próteses totais com três diferentes conceitos oclusais

Pós-graduação em Reabilitação Oral - FOAR

Efeitos dos ascorbato de sódio e alfatocoferol na resistência à fratura, resistência de união e na interface adesiva na dentina de dentes tratados endodonticamente submetidos a clareamento dental com peróxido de hidrogênio

Pós-graduação em Ciências Odontológicas - FOAR

Avaliação tomográfica da reabsorção radicular apical e das alterações no tecido periodontal de suporte induzidas pelo aparelho Herbst

Pós-graduação em Ciências Odontológicas - FOAR

Relaxamento de tensão em molas T de Beta-Titânio: avaliação e uma possivel solução

Pós-graduação em Ciências Odontológicas - FOAR

Larvae of proceratophrys melanopogon (amphibia: anura), with emphasis on internal oral morphology and comparisons with p. cururu and p. moratoi

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of Tapered and External Hexagon Connections on Bone Stresses Around Tilted Dental Implants: Three-Dimensional Finite Element Method With Statistical Analysis

Background: The purpose of this study is to analyze the tension distribution on bone tissue around implants with different angulations (0 degrees, 17 degrees, and 30 degrees) and connections (external hexagon and tapered) through the use of three-dimensional finite element and statistical analyses.Methods: Twelve different configurations of three-dimensional finite element models, including three inclinations of the implants (0 degrees, 17 degrees, and 30 degrees), two connections (an external hexagon and a tapered), and two load applications (axial and oblique), were simulated. The maximum principal stress values for cortical bone were measured at the mesial, distal, buccal, and lingual regions around the implant for each analyzed situation, totaling 48 groups. Loads of 200 and 100 N were applied at the occlusal surface in the axial and oblique directions, respectively. Maximum principal stress values were measured at the bone crest and statistically analyzed using analysis of variance. Stress patterns in the bone tissue around the implant were analyzed qualitatively.Results: The results demonstrated that under the oblique loading process, the external hexagon connection showed significantly higher stress concentrations in the bone tissue (P < 0.05) compared with the tapered connection. Moreover, the buccal and mesial regions of the cortical bone concentrated significantly higher stress (P < 0.005) to the external hexagon implant type. Under the oblique loading direction, the increased external hexagon implant angulation induced a significantly higher stress concentration (P = 0.045).Conclusions: The study results show that: 1) the oblique load was more damaging to bone tissue, mainly when associated with external hexagon implants; and 2) there was a higher stress concentration on the buccal region in comparison to all other regions under oblique load.

Comparação da razão carga/deflexão entre fios ortodônticos de Ni-Ti termoativados 0,014”x0,025” e 0,016”x0,022”

The knowledge of the mechanical properties of nickel-titanium (NiTi) termoactives of the more accessible of the domestic market is still limited. Given this, the objective of this study was to evaluate and compare through deflection tests in brackets NiTi wires 03 term rectangular gauge 0.014 '' enabled x 0.025 '' and 0.016 '' x 0.022 '' of different brands (MORELLI (R), ORMCO (R) ORTHOSOURCE (R), ORTHOMETRIC (R), EURODONTO (R) and ADITEK (R)). All tests were carried out on universal testing machine EMIC DL 2000 under identical conditions and controlled at a temperature of 36 degrees C +/- 0.5 degrees C. Five measurements (N= 5) were performed for each thickness/wire tag that was deflected up to a limit of 4.0mm at a speed of 1.0mm/min. Each 0.2mm (round trip) of corresponding strength measured deflection for the construction of the graph of force x deflection at Tesc program version 3.04. Each graphic was evaluated according to the following variables: beginning of the Martensitic transformation (cN and mm), maximum strength (cN), the beginning and end of the plateau of deactivation (cN and mm) and length (mm) plateau. The average and standard deviation were calculated for all variables and statistical analysis was made by ANOVA tests 2 criteria and Turkey or Kruskal-Wallis and Dunn, a 5% level of significance. The results showed that the tests of 0.014 '' x0.025 '' ORTHOMETRIC (R) brands and ORMCO (R) showed the best results, as well as the wires of the MORELLI (R) and ORTHOSOURCE (R) to wires 0.016 '' x0.022 ''. In General, the gauge wires 0.014 '' x0.025 '' showed strength levels on the plateau of deactivation to 6 x smaller than 0.016 '' x0.022 '' caliber.

Midpalatal suture maturation: Classification method for individual assessment before rapid maxillary expansion

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

Craniocervical posture and craniofacial morphology

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

Time reduction of light curing: Influence on conversion degree and microhardness of orthodontic composites

Introduction: The aim of this study was to assess the influence of curing time and power on the degree of conversion and surface microhardness of 3 orthodontic composites. Methods: One hundred eighty discs, 6 mm in diameter, were divided into 3 groups of 60 samples according to the composite used-Transbond XT (3M Unitek, Monrovia, Calif), Opal Bond MV (Ultradent, South Jordan, Utah), and Transbond Plus Color Change (3M Unitek)-and each group was further divided into 3 subgroups (n = 20). Five samples were used to measure conversion, and 15 were used to measure microhardness. A light-emitting diode curing unit with multiwavelength emission of broad light was used for curing at 3 power levels (530, 760, and 1520 mW) and 3 times (8.5, 6, and 3 seconds), always totaling 4.56 joules. Five specimens from each subgroup were ground and mixed with potassium bromide to produce 8-mm tablets to be compared with 5 others made similarly with the respective noncured composite. These were placed into a spectrometer, and software was used for analysis. A microhardness tester was used to take Knoop hardness (KHN) measurements in 15 discs of each subgroup. The data were analyzed with 2 analysis of variance tests at 2 levels. Results: Differences were found in the conversion degree of the composites cured at different times and powers (P < 0.01). The composites showed similar degrees of conversion when light cured at 8.5 seconds (80.7%) and 6 seconds (79.0%), but not at 3 seconds (75.0%). The conversion degrees of the composites were different, with group 3 (87.2%) higher than group 2 (83.5%), which was higher than group 1 (64.0%). Differences in microhardness were also found (P < 0.01), with lower microhardness at 8.5 seconds (35.2 KHN), but no difference was observed between 6 seconds (41.6 KHN) and 3 seconds (42.8 KHN). Group 3 had the highest surface microhardness (35.9 KHN) compared with group 2 (33.7 KHN) and group 1 (30.0 KHN). Conclusions: Curing time can be reduced up to 6 seconds by increasing the power, with a slight decrease in the degree of conversion at 3 seconds; the decrease has a positive effect on the surface microhardness.

Influence of cone-beam computed tomography image artifacts on the determination of dental arch measurements

Objective: To compare dental plaster model (DPM) and cone-beam computed tomography (CBCT) in the measurement of the dental arches, and investigate whether CBCT image artifacts compromise the reliability of such measurements.Materials and Methods: Twenty patients were divided into two groups based on the presence or absence of metallic restorations in the posterior teeth. Both dental arches of the patients were scanned with the CBCT unit i-CAT, and DPMs were obtained. Two examiners obtained eight arch measurements on the CBCT images and DPMs and repeated this procedure 15 days later. The arch measurements of each patient group were compared separately by the Wilcoxon rank sum (Mann-Whitney U) test, with a significance level of 5% (alpha = .05). Intraclass correlation measured the level of intraobserver agreement.Results: Patients with healthy teeth showed no significant difference between all DPM and CBCT arch measurements (P > .05). Patients with metallic restoration showed significant difference between DPM and CBCT for the majority of the arch measurements (P > .05). The two examiners showed excellent intraobserver agreement for both measuring methods with intraclass correlation coefficient higher than 0.95.Conclusion: CBCT provided the same accuracy as DPM in the measurement of the dental arches, and was negatively influenced by the presence of image artifacts.

Análise tridimensional das alterações dento-alveolares em molares superiores após o uso do aparelho de Herbst

Pós-graduação em Ciências Odontológicas - FOAR

Ação do curcumin sobre os períodos iniciais da carcinogênese bucal induzida por 4-NQO em modelo murino

Pós-graduação em Odontologia - FOAR

Estudo comparativo da eficacia de dois adesivos dentinarios e um cimento de ionomero de vidro empregados na adesão do amalgama a dentina

Pós-graduação em Odontologia Restauradora - ICT