Spectrophotometric analysis of dental bleaching after bonding and debonding of orthodontic brackets

Abstract Introduction: The aim of this study was to evaluate the bleaching effect after aging sim- ulation in teeth submitted to bonding and debonding of orthodontic brackets. Materials and methods: For this study, 90 human premolars were selected, and randomly divided into 6 groups: control, bleaching, and other 4 groups submitted to bleaching after bonding and debonding brackets using different methods. Color measurement of sample through the CIE L*a*b* system was performed in three moments: T1 – after brackets debonding, T2 – after staining cycling, and T3 – after bleaching. For evaluation of results among the components L*, a* and b*, the two criteria analysis of variance and the multiple comparison Tukey test (p < 0.05) were used. Results: Statistically significant difference was observed among the groups submitted to brackets bonding and debonding through self-conditioning adhesive system and tungsten drill, also the con- trol and bleaching groups between the moments T1 e T2. Conclusion: Bonding and debonding brackets methods tested in this study showed influence on the sample color change, and after the tooth bleaching process, only the group without brackets previous bonding achieved the color value presented before the staining and aging of samples in the brackets absence

Endodontic Management of Open Apex Teeth Using Lyophilized Collagen Sponge and MTA Cement: Report of Two Cases

Teeth with open apices, such as in immature teeth or those with apical root resorption are clinical cases with difficult immediate resolution. With the use of mineral trioxide aggregate (MTA) in dentistry, it was possible to optimize the treatment time of these cases by immediate placement of apical plug and the root canal filling. However, some negative effects can occur if MTA is extruded beyond the apex. To avoid this accident, it has been recommended to use of an apical matrix prior to placement of MTA. This study reports two clinical cases of apical plug placement in teeth with pulp necrosis and open apices. One case had an immature apex due to dental trauma and the other case had apical resorption due to the presence of endodontic infection in the root canal. MTA apical plug with approximately 4 mm thickness, was placed in the apical zone of the root and immediately the canal was obturated with gutta-percha and endodontic sealer. Follow-up evaluations showed clinical and radiographic evidence of success.Keywords: Apex; Collagen; Endodontics; Mineral Trioxide Aggregat

Disfunção craniomandibular em pacientes desdentados totais com alteração da dimensão vertical. -

O presente estudo procurou avaliar a prevalência de sinais e sintomas de disfunção craniomandibular (D.C.M.) em 100 pacientes desdentados totais, portadores de próteses totais duplas, dos quais 58 apresentavam dimensão vertical normal (Grupo 1) e 42 dimensão vertical com alteração (Grupo 2). Os dados foram obtidos a partir de um índice anamnésico simplificado e de exame físico. Após a análise estatística, foi possível observar que: 1. em relação ao índice anamnésico utilizado, a análise estatística mostrou haver associação entre a dimensão vertical e os sintomas de D.C.M. (p=0,016); 2. quanto ao número de regiões sensíveis à palpação muscular, foi constatada uma associação estatisticamente significante com a dimensão vertical (p=0,014); 3. quando avaliados os grupos musculares isoladamente, apenas a palpação intraoral do músculo pterigóideo lateral apresentou associação estatisticamente significante com a dimensão vertical (p=0,05). Conclui-se, por meio deste estudo, que existe uma evidência de associação entre a dimensão vertical e os sinais e sintomas de D.C.M. considerando-se a metodologia empregada e a população estudada.The present study evaluated the prevalence of signs and symptoms of temporomandibular disorders in 100 patients wearing complete upper and lower dentures, 58 with normal vertical dimension (Group 1) and 42 with altered vertical dimension (Group 2). The data were obtained utilizing a simplified anamnestic index and of physical exam. After the statistical analysis, it was possible to conclude that: 1. there was a significant correlation between the vertical dimension and the symptoms of temporomandibular disorders, when utilizing the anamnestic index (p=0,016); 2. there was a significant correlation between the vertical dimension and the number of tenderness sites during muscle palpation (p=0,014); 3. when appraised the muscular groups separately, just the tenderness to the intra-oral palpation of the lateral pterygoid muscle showed a statistically significant correlation with the vertical dimension (p=0,05). It could be concluded that there was an association between the vertical dimension and the signs and symptoms of temporomandibular disorders, for this sub population that has been analysed

Prevalência de sinais e sintomas de disfunção craniomandibular em pacientes desdentados totais (com dimensão vertical restabelecida e diminuída) e pacientes dentados naturais

O presente estudo procurou avaliar a prevalênica de sinais e sintomas de Disfunção Craniomandibular (DCMs) em três grupos específicos de pacientes: Grupo A1- Pacientes desdentados totais com a dimensão vertical corretamente estabelecida (constituído por 74 indivíduos); Grupo A2- Pacientes desdentados totais com a dimensão vertical diminuída (constituído por 80 indivíduos); Grupo B- Pacientes dentados com a dimensão vertical preservada (constituído por 61 indivíduos). Os sintomas foram avaliados através de índice anamnésico e os sinais estudados foram à sensibilidade muscular e articular à palpação, os sons articulares e os hábitos parafuncionais. Associação estatisticamente significante foi constatada para o índice anamnésico (prevalente em A2 e B), o número de regiões sensíveis à palpação muscular (prevalente em A2), os hábitos parafuncionais (prevalente em B) e os sons articulares (prevalente em B). Pode-se concluir que a dimensão vertical pode ser um fator contribuinte ou até mesmo perpetuante da disfunções craniomandibulares.The present study evaluated the prevalence of signs and symptoms of craniomandibular disorders (CMDs) in three specific groups of patients: Group A1 - Edentulous patients with the vertical dimension correctly established (constituted by 74 individuals); Group A2 - Edentulous patients with the reduced vertical dimension (constituted by 80 individuals); Group B - Dentate patients with the preserved vertical dimension (constituted by 61 individuals). The symptoms were appraised through anamnestic index and the investigated signs were the muscular and articular tenderness to the palpation, the joint sounds and the parafunctional habits. A significant correlation was verified between the groups and the anamnestic index (prevalent in A2 and B), the number of tenderness areas to the muscular palpation (prevalent in A2), the parafunctional habits (prevalent in B) and the joint sounds (prevalent in B). It could be concluded that the vertical dimension can be a contributor factor to the arising or to the perpetuation of CMDs.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Matriz Bertholdo/Ricci/Barrotte (BRB): uma simplificação de técnica para obtenção de guia de estratificação com compósitos

Advanced Layering composite resins can be facilitated by a technique called "Lingual Matrix", where a guide is made of elastomer by molding a previously waxed tooth or sculped in an intraoral test drive restoration. This technique has many advantages to sophisticated layering, facilitation stratification, anatomic construcrion and the stages of finishing and polishing. However, in some clinical situations, the unfolding of the steps to obtains this matrix can be time consuming or even infeasible. To facilitate the achievement of this apparatus, a technique was idealized allowing significant reducrion in clinical time. This matrix, called the "BRB Matrix" is widly discussed in a didactic and clinical manner in this article, presenting its advantages in clinical cases where it is imperative to use a guide for conduction a controlled layering. The simplicity of this approach, as well as reduced clinical time and finacial costs turn it feasible in an everyday clinical practice.A estratificação de resinas compostas por meio de métodos sofisticados pode ser facilitada pela técnica denominada Matriz Lingual, em que uma guia é confeccionada em elastômero, por meio da moldagem de uma superfície palatina, previamente encerada ou esculpida em um ensaio restaurador intraoral. Essa técnica apresenta muitas vantagens, facilitando a estratificação, a construção anatômica e as fases de acabamento e polimento. Porém, em algumas situações clínicas, o desenrolar das etapas para se obter essa matriz poder moroso ou até mesmo inviável. Visando a facilitar a obtenção de tal aparato, uma técnica foi idealizada para permitir significativa redução do tempo clinico. Tal matrz, denominada Matriz BRB, é amplamente discutida de maneira didática e clínica neste artigo, que apresenta suas vantagens em casos em que é imperativo o uso de guia para realização de uma estratificação controlada. A simplicidade dessa abordagem, bem como a redução do tempo clínico e de custos financeiros, a torna viável em clínica cotidiana

In vitro comparisons of casting retention on implant abutments among commercially available and experimental castor oil-containing dental luting agents

Statement of problem Although cement-retained implant prostheses are widely used, the quantification of optimal retention remains controversial, and new dental luting agents should be evaluated. Purpose The purpose of this study was to compare, in vitro, the casting retention on implant abutments after cementation with 3 commercially available luting agents and an experimental luting agent (castor oil polyurethane, COP) with variable weight percentages (wt%) of calcium carbonate (CaCO3). Material and methods Seventy-two palladium-silver cast copings were fabricated and divided into 6 groups: Temp Bond interim cement (TB); zinc phosphate cement (ZP); Rely X ARC resin cement (RX); pure COP (COP); COP + 10% wt% CaCO3 filler (COP 10); and COP + 50% wt% CaCO3 filler (COP 50). After cementation, the specimens were stored in distilled water at 37°C for 24 hours and subjected to removal force tests in a universal testing machine (5 kN; 0.5 mm/min). Statistical analyses were performed with the Kruskal-Wallis and Student-Newman-Keuls tests (α=.05). Results The median values of casting retention (N) were as follows: TB=57.20 ±10.4; ZP=343.56 ±50.3; RX=40.07 ±9.7; COP=258.98 ±41.4; COP 10=466.57 ±79.3; and COP 50=209.63 ±31.4. The Kruskal-Wallis test showed significant differences among the groups (P<.01). TB and RX had the lowest mean retention values; COP, COP 10, and COP 50 were equal to ZP, and COP 10 had the highest retention. Conclusions The casting retention on implant-abutments provided by COP was similar to that of copings cemented with zinc phosphate and may be influenced by the addition of calcium carbonate. © 2013 The Editorial Council of the Journal of Prosthetic Dentistry.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Esthetic and function improvement by direct composite resins and biomimetic concept

Aim: This case report describe a resin layering restorative technique based on biomimetic concept to improve esthetics in a patient with dental defects that affected both enamel and dentin in anterior teeth. Background: Severe structural defect in anterior teeth compromises esthetics and it is a high challenge to become the defect imperceptible after the restoration. Case description: A clinical sequence of applying different composite resin layers allowed the reproduction of the interaction between hard dental tissues and the restorative material. Conclusion: This technique achieved a satisfactory final esthetic outcome, preserving sound teeth structure and at same time, improved the quality of life of the young patient. Clinical significance: The utilization of the biomimetic concept to increase a disharmonic smile with dental defects is based in a conservative approach, which reached a satisfactory and esthetic outcome

Mechanical strength and analysis of fracture of titanium joining submitted to laser and tig welding

This study compared the tensile strength and fracture mechanism of tungsten inert gas (TIG) welds in cylindrical rods of commercially pure titanium (cp Ti) with those of laser welds and intact samples. Thirty dumbbell-shaped samples were developed by using brass rods as patterns. The samples were invested in casings, subjected to thermal cycles, and positioned in a plasma arc welding machine under argon atmosphere and vacuum, and titanium was injected under vacuum/pressure. The samples were X-rayed to detect possible welding flaws and randomly assigned to three groups to test the tensile strength and the fracture mechanism: intact, laser welding, and TIG welding. The tensile test results were investigated using ANOVA, which indicated that the samples were statistically similar. The fracture analysis showed that the cpTi samples subjected to laser welding exhibited brittle fracture and those subjected to TIG welding exhibited mixed brittle/ductile fracture with a predominance of ductile fracture with the presence of microcavities and cleavage areas. Intact samples presented the characteristic straightening in the fracture areas, indicating the ductility of the material