ABSTRACT
Objective: to investigate the effect of two natural cross-linkers on microtensile bond strength (µTBS) and evaluate their influence on the durability of the resin dentin bonds. Material and Methods: the Moringa oleifera and Centella asiatica plant extracts were qualitatively tested with high-performance thin layer chromatography (HPTLC) for the presence of phenols. The phenolic content ranged from 27 to 30 gallic acid equivalents (GAE), µg/mg of dry weight. After etching, two concentrations (5% and 1%) of these two extracts were prepared and used as pretreatment liners on dentin. They were applied for a min. After restoration with resin composite, dentin resin beams were prepared. The study groups were 5% Moringa, 1% Moringa 5% Centella 1% Centella, and control (without cross-linker application). For each group, half of the samples underwent µTBS testing after 24 hours, while the remaining half were immersed in artificial saliva to assess the bond's longevity after 6 months of ageing. Statistical analysis was performed using one-way ANOVA followed by Tukey's post hoc test. Results: both 5% and 1% Moringa showed a significant difference (p<0.05) compared to the other groups at both intervals. However, after ageing, the specimens in the control and 1% Centella groups resulted in a significant decrease in µTBS. Conclusion: overall, both concentrations of Moringa (5% and 1%) were effective in stabilising the bond during both intervals.(AU)
Objetivo: investigar o efeito de dois reticuladores naturais na resistência de união (µTBS) à microtração e avaliar sua influência na durabilidade da adesão da resina à dentina. Material e Métodos: extratos das plantas Moringa oleifera e Centella asiatica foram qualitativamente testados através de cromatografia em camada fina de alta performance (HPTLC) para a presença de fenóis. O conteúdo fenólico alcançou entre 27 a 30 equivalentes de ácido gálico (GAE), µg/mg de peso seco. Após o condicionamento, duas concentrações (5% e 1%) dos extratos foram preparadas e utilizadas como forros de pré-tratamento em dentina. Eles foram aplicados por um minuto. Após a restauração com resina composta, palitos de dentina e resina foram preparados. Os grupos foram 5% Moringa, 1% Moringa, 5% Centella, 1% Centella e controle (sem aplicação de reticulador). Para cada grupo, metade das amostras foram submetidas ao teste µTBS após 24 horas, enquanto a outra metade foi imersa em saliva artificial para avaliar a longevidade adesiva após 6 meses de envelhecimento. Foi realizada análise estatística através de ANOVA 1-fator, seguido do teste post hoc de Tukey. Resultados: ambas as concentrações de 5% e 1% de Moringa demonstraram diferença significativa (p<0.05) comparadas aos outros grupos em ambos os intervalos. No entanto, após o envelhecimento, os espécimes dos geupos controle e 1% de Centella resultaram em uma redução significativa de µTBS. Conclusão: no geral, ambas as concentrações de Moringa (5% e 1%) foram efetivas em estabelecer a adesão em ambos os intervalos (AU)
Subject(s)
Humans , Dentin-Bonding Agents/analysis , Composite Resins/analysis , Cross-Linking Reagents/analysis , Centella/chemistry , Moringa oleifera/chemistry , Flavonoids/chemistry , Plant Extracts/chemistry , Chromatography, High Pressure Liquid , Tooth Injuries , Fibrillar Collagens/metabolism , Polyphenols/chemistryABSTRACT
Aim: This in vitro study was designed to evaluate and compare the shear bond strength of stainless steel brackets bonded to ceramic crowns etched with Hydrofluoric acid and Lasers. Place of Study: This study was carried out in the Department of Orthodontics and Dentofacial Orthopedics, RMDCH, Annamalai University, Chidambaram, 2012 to 2014. Methodology: Forty ceramic crowns were fabricated using Vita ceramic blocks and were mounted on acrylic blocks. Samples were randomly divided into four groups and stored in artificial saliva. Ceramic surfaces from Group A and B were etched with 4% hydrofluoric acid and Group C and D were etched with Lasers respectively and they were bonded to stainless steel brackets. Samples from group A and C were bonded with stainless steel brackets using light cure GIC and samples from group B and D were bonded with stainless steel brackets using light cure composite. Debonding of the brackets from ceramic surface was carried out using universal testing machine and the debonded surface texture was analysed using SEM. Results: Both mean values and standard deviations were estimated from the sample for each study group. Mean values of shear bond strengths were compared by using one- way ANOVA followed by Tukey-HSD procedure. Pearson chi-square test was done to test the significance of shear bond strength between study groups. Mean shear bond strength in Group D (9.23±2.74 Mpa) was significantly higher than remaining tested groups followed by Group B (7.5±1.029 Mpa), Group C(6.823±1.202 Mpa) and Group A (6.11±1.019 Mpa) (p< 0. 05). Conclusion: Er-Cr: YSGG laser etching on roughened ceramic can be used as an alternative for bonding orthodontic attachments to ceramic surfaces.
ABSTRACT
Aims: Fracture of dentures is a common clinical finding in daily prosthodontic practice, resulting in great inconvenience to both the patient and the dentist. A satisfactory repair should be costeffective, simple to perform, and quick. This study evaluated and compared the transverse strength of two heat cure denture base resins repaired with auto polymerizing resin by wetting with methyl methacrylate (MMA) at different time intervals. Materials and Methods: Stellon and Trevalon denture base materials were used in the study. A total of 200 heat cure acrylic resin specimens (100 specimens each of Stellon and Trevalon acrylic material) with the dimensions of (65 mm x 10 mm x 3 mm) were prepared. The specimens were divided with 10 specimens for each of the test groups (n =10). The test groups were designated as Group A through J. Repair gap of 2 mm was prepared in the centre of the specimen. The repair surface of the specimens were wetted with MMA at different time intervals (1, 2, 3, 4, 5, 10, 15 and 30 minutes) and repaired by using auto polymerizing resin. The transverse strength of the repaired specimens was tested by a 3 point bending test. All data was statistically analyzed with one-way ANOVA, differences within the groups were analyzed by independent sample t -test. Results: The results showed that the significant difference between the specimens wetted with MMA at different time intervals. A gradual increase was shown in the mean transverse strength of repaired specimens wetted from 1 minute to 5 minutes in Stellon and from 1 minute to 10 minutes in Trevalon. Conclusion: Wetting the repair surfaces with MMA for a period of more than 5 minutes and 10 minutes in case of Stellon and Trevalon respectively increases the incidence of adhesive failure in the repaired specimens.
ABSTRACT
Aims: This in vitro study was designed to investigate the exogenous erosive potential of most commonly used pediatric syrup medicaments on primary teeth. Place and Duration of Study: Department of Pediatric Dentistry, Vishnu Dental College, Bhimavaram, India, 2012 to 2013. Methodology: The erosive potential of 17 syrups was assessed by measuring their inherent pH, titratable acidity, viscosity and ability to erode enamel. The inherent pH and titratable acidity of syrups were measured using digital pH meter and viscosity was determined using Brookfield viscometer. Enamel surface changes were evaluated using optical 3D profilometer. Results: Api –up (appetizer) showed the least pH and Azee (Azithromycin) exhibited the highest pH. The titratable acidity was greater for Api-up (5.40ml) and least for Tonoferron (0.20ml). Asthalin exhibited highest viscosity and Ondem showed least viscosity. All the test syrups caused some degree of enamel loss, however, Api – up caused the greatest and Azee caused the least degree of enamel loss at three time intervals. Conclusion: The medicated syrups with low inherent pH and high viscosity showed to cause a greater dissolution of enamel. However, certain syrups with low viscosity had shown higher degree of enamel loss due to their inherent acidic pH and those with high viscosity Showed lesser degree of enamel loss due to their basic pH. Hence, these results proved that inherent pH is the most critical factor for erosion.