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Introduction: After fixed orthodontic treatment, following bracket removal, the debonding procedure should lead to restitutio ad integrum of the enamel or, at least, restore the enamel surface as closely as possible to its pretreatment condition. Adhesion of brackets in orthodontics is that they should be strong enough to prevent failure during all treatment but also low enough, so that enamel damage would be minimal during bracket removal after treatment. Material and Methods: A total of 60 premolars were collected and stored in distilled water. The extracted teeth were divided into two groups of 30 each, group A was to be bonded with self?cure adhesive while group B light cure adhesive was to be used. A standardised protocol was followed for adhering the brackets to the tooth surfaces. All the teeth were bonded with metal brackets (3M Unitek, Gemini Twin Brackets 0.022 slot). In group A, bonding adhesive (3M Unitek self cure adhesive primer) was applied. In group B, the bonding adhesive (3M Unitek light cure adhesive primer) was photopolymerized for 10 seconds after application. Results: Surface roughness of enamel as assessed by profilometry shows that light cure adhesive creates more roughness as compared to self cure adhesive. To conclude, self cure adhesive is clinically better than light cure adhesive. Discussion: In the present study enamel surface roughness were compared after debonding. Enamel surface roughness after bracket debonding depends o
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Bulk-fill composite resin are simple to operate, and they reduce polymerization shrinkage and microleakage compare to traditional resin-based composites. However, their clinical application could be affected by numerous factors, such as the material itself, light curing, placement techniques, storage condition, and preheating. This review aimed to summarize the definitions, classifications, indications, clinical properties, and influencing factors of the clinical application of bulk-fill resin-based composites and discuss the ways to improve their clinical effectiveness.
Subject(s)
Composite Resins , Dental Materials , Materials Testing , Polymerization , Surface PropertiesABSTRACT
Introduction: The purpose of this study is to evaluate the effect of three storage temperatures on microhardness of high and low viscosity bulk-fill materials and compare them with conventional resin-based composite materials. Materials and method: Six composite resin-based materials were used in this study (TN, TNB, TNF, FZ250, FB and FBF) samples were subdivided into three groups based on the pre-curing storage temperature (5°C, 23°C and 37°C). Light polymerization for each material was performed based on the manufacturer’s recommendation using Bluephase G2 curing unit (Ivoclar Vivadent, Schaan, Liechtenstein) in a high-intensity mode with an irradiance of 1200 mW/cm2. Vickers hardness values of top and the bottom surfaces of each sample were evaluated using (NOVA 130 series, Vickers and Knoop hardness testing instrument) under a 200 g load with a dwell time of 10 sec. Also three indentations with the random distance of 1 mm were taken from the top and the bottom surfaces of each sample and a mean Vickers hardness (VHN) value were calculated (n=18 top and n=18 bottom). The mean bottom/top ratio was calculated by dividing VHN of the bottom surface by VHN of the top surface. Results: When the tested materials were stored at room temperature (23°C) before testing in the present study, they failed to reach the minimum 80% of the mean bottom to top hardness value ratio except for FZ250 and FBF, where they reached 97.8% and 83.2% respectively. Where in samples that were stored refrigerated at 5°C all the materials have reached the minimum 80% of the mean bottom to top hardness value ratio except for FBF (77.3%) and TB (77.2%). On the other hand, the only material that reached the minimum 80% of the mean bottom to top hardness value ratio when the materials were stored at 37°C was FZ250 (93.5%). Conclusion: Despite the promising results from this preliminary study, regarding improvement of microhardness with refrigerated composite resins, further research has to be conducted. The enhancement of hardness values associated with preheated composites could be beneficial in countries with warm climate such as Saudi Arabia. The association of precooled composite resin and the use of the LED curing units could be recommended to improve resin-based composite hardness. Further research is needed to evaluate the other mechanical properties and whether or not they are influenced by storage temperature.
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Abstract The aim of this study was to evaluate the degree of conversion, color stability, chemical composition, and bond strength of a light-cured resin cement contaminated with three different hemostatic solutions. Specimens were prepared for the control (uncontaminated resin cement) and experimental groups (resin cement contaminated with one of the hemostatic solutions) according to the tests. For degree of conversion, DC (n = 5) and color analyses (n = 10), specimens (3 mm in diameter and 2 mm thick) were evaluated by Fourier transform infrared spectroscopy (FTIR) and CIELAB spectrophotometry (L*, a*, b*), respectively. For elemental chemical analysis (n = 1), specimens (2 mm thick and 6 mm in diameter) were evaluated by x-ray energy-dispersive spectroscopy (EDS). The bond strengths of the groups were assessed by the microshear test (n = 20) in a leucite-reinforced glass ceramic substrate, followed by failure mode analysis by scanning electron microscopy (SEM). The mean values, except for the elemental chemical evaluation and failure mode, were evaluated by ANOVA and Tukey's HSD test. The color stability was influenced by storage time (p<0.001) and interaction between contamination and storage time (p<0.001). Hemostop and Viscostat Clear contamination did not affect the DC, however Viscostat increased the DC. Bond strength of the resin cement to ceramic was negatively affected by the contaminants (p<0.001). Contamination by hemostatic agents affected the bond strength, degree of conversion, and color stability of the light-cured resin cement tested.
Resumo O objetivo desse estudo foi avaliar o grau de conversão, estabilidade de cor, composição química e resistência de união de um cimento resinoso fotoativado contaminado com três soluções hemostáticas diferentes. Foram preparadas amostras para o grupo controle (cimento não contaminado) e grupos experimentais (cimento contaminado com uma das soluções hemostáticas) de acordo com os testes. Para o grau de conversão e análise de cor (n=10), as amostras (3 mm de diâmetro e 2 mm de espessura) foram avaliadas por espectroscopia de infravermelho com transformação de Fourier (FTIR) e espectrofotometria CIELAB (L*, A*, B*), respectivamente. Para a análise química elementar (n=1), os espécimes (2 mm de espessura e 6 mm de diâmetro) foram avaliados por espectroscopia de energia dispersiva de raios-x (EDS). As resistências de união dos grupos foram avaliadas pelo ensaio de microcisalhamento (n=20) em um substrato cerâmico de vidro reforçado com leucita, seguida da análise de modo de falha por microscopia eletrônica de varredura (MEV). Os valores médios, com exceção da avaliação química e do modo de falha, foram avaliados por ANOVA e pelo teste de Tukey. A estabilidade de cor foi influenciada pelo tempo de armazenagem (p<0,001) e interação entre a contaminação e o tempo (p<0,001). A contaminação pelo Hemostop e Viscostat Clear não influenciaram no GC, porém a contaminação com Viscostat aumentou o GC. A resistência de união do cimento a cerâmica foi negativamente afetada pelos contaminantes (p<0,001). A contaminação por agentes hemostáticos afetou a resistência de união, o grau de conversão e a estabilidade de cor do cimento resinoso fotoativado testado.
Subject(s)
Hemostatics , Resin Cements/chemistry , Color , Microscopy, Electron, Scanning , Solutions , Spectrum Analysis , Surface PropertiesABSTRACT
Aims and Objectives: To use antibacterial agents with two conventional bonding systems and evaluate the shear bond strength (SBS) of bracket to enamel. Materials and Methods: Overall, 120 human‑extracted first premolars were used. The specimens were equally divided into six sub‑groups of 20 samples. Control groups were bonded with Transbond XT™ light cure (Group I, after etching with 37% phosphoric acid, 3M Unitek™) and Unite™ self‑cure adhesive (Group II, after etching with 37% phosphoric acid, 3M Unitek™). Experimental groups included teeth surface first coated with Clearfil Protect Bond™ (Kuraray, Osaka, Japan) (and then bonded with Transbond XT™ [Group III] or Unite™ [Group IV]) or bonded with Uni‑Etch™ antibacterial self‑etchant (and then bonded with Transbond XT™ [Group V] or Unite™ [Group VI]). The third generation MBT bracket bonding system with 0.022 slots was used for bonding. All specimens were tested on Instron machine 5567 (SIES Institute of packaging, Nerul, Navi Mumbai, India) to evaluate the SBS. The sheared surfaces were also investigated with a stereomicroscope to assess adhesive remnants index (ARI scores) on the specimen surfaces. Results: Mean SBS in Group I–Group VI was 10.53 (2.91), 9.12 (2.56), 9.86 (1.98), 6.96 (2.92), 9.57 (2.02), and 7.65 (2.34) megapascals, respectively. Significant differences were only seen between Group III and IV and between Group II and IV. With respect to ARI scores, significant differences were seen only for comparison between Groups II, IV, and VI. Conclusion: Newly developed antibacterial agent could be used with conventional bonding systems effectively to decrease white spots; when used with Transbond XT™ light cure, the original SBS did not get affected, but when used with Unite™ self‑cure bonding system, it led to reduced SBS significantly.
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Background: The degree of conversion of dental adhesive is an important parameter since poor mechanical properties are related to low percentage of monomer-to-polymer conversion within resin-based materials. Objectives: To evaluate the influence of polymerization time and light guide distance on the degree of conversion (DC) of three contemporary dental adhesives. Materials and Methods: The spectral data of ExciTE DSC, Single Bond ® , and Adper ® Prompt L-Pop were analyzed using FTIR spectroscopy after 20 s, 40 s, and 60 s of photoactivation times. Light tip distances were kept at 1, 3, and 6 mm during the exposures. Statistics: Data were analyzed using ANOVA and Tukey's test (α = 0.05). Results: Within groups, greater DC values were found using a tip distance of 1 mm or a 60-s curing time for Single Bond ® (59%) and Adper ® Prompt L-Pop (65%). No statistically significant difference (P > 0.05) was found using either 1 mm or 3 mm tip distances after 20 s, 40 s, and 60 s of light curing time for Single Bond ® . ExciTE ® DSC showed the greatest DC values with light tip distances of 1 mm (90%) and 3 mm (89%), using 60 s of light curing. Conclusion : The self-etch adhesive Adper ® Prompt L-Pop could be applied in shallow cavity preparations and must be light cured for at least 40 s. The light-cured total-etch adhesive ExciTE ® DSC could be applied in every restorative scenario if the curing time is extended up to 60 s or if the tip distance is extended up to 3 mm.
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Introduction: The aim of the study was to evaluate and compare the clinical performance of two color changing bracket bonding adhesives (Transbond Plus and Grengloo), in terms of bond failure rate, bonding time and time taken by the adhesives to change color. Methods: Eight consecutive patients seeking orthodontic fixed appliance therapy were bonded using Cross arch Split mouth technique, which involves the placement of two varieties of bracket bonding adhesives in diagonally opposite quadrants and cured using a visible light curing unit. The time taken by the adhesive to change color during bonding and the bonding time was noted using a stop watch. The bond failure rates of both the adhesives were evaluated by a thorough follow up of individual case, as and when they reported to the department with a debonded bracket. The data collected were subjected to statistical analysis using Chi square test and student’s t-test. Results: The overall bond failure rate for two color changing adhesives were 7.1 % and 8.6 %,bonding time was 59.1 and 57.4 seconds per tooth and time to change color was 45.9 and 46 seconds. Interpretation & Conclusion: There were no significant differences between the failure rates, bonding time and time taken by both the adhesives to change color showing that both are clinically efficient and effective. Clinically they are preferred over the non color changing bracket bonding adhesives as these materials save clinical chairside time because of their color changing property which helps in easy flash removal while bonding brackets.
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The purpose of this study was to evaluate the tooth color changes of resin bonding sites and their adjacent sites on orthodontic bracket bonding. Sixty extracted sound premolars were used and the tooth color was recorded according to the CIE L(*)a(*)b(*) color system using a spectrophotometer. The tooth colors of the twenty premolars were measured and compared before bracket bonding and after removal. On a further twenty premolars, the tooth color was measured before and after only primer application. In the change of L(*) values, according to the bracket bonding and primer application, the lightness was decreased, and in the change of a(*) and b(*) values, the color was changed into a more yellowish color. The color differences (delta E(*)) were calculated from the L(*)a(*)b(*) values and compared with the standard value of clinical detection (delta E(*)=3.7). The color differences between before the bracket bonding and after removal noted exceeded the standard value and those of between before and after the primer application were not larger than the standard value. Toothbrushing was performed after application of the primer to evaluate the color changes according to the primer abrasion. As a control, toothbrushing was performed on the last twenty premolars. The color differences noted were larger than the standard value after toothbrushing. Also, to evaluate the color changes of the tooth which is exposed to sun irradiation after bracket removal, additional photoaging was performed and the color was measured for all teeth. The additional color differences after photoaging were smaller than the standard value. The above results suggest that the tooth color changes after fixed orthodontic treatment.
Subject(s)
Bicuspid , Orthodontic Brackets , Solar System , Tooth , ToothbrushingABSTRACT
Objective To evaluate the clinical effect of light cure Dyractflow (LCDF) in pit and fissure enamel-plasty sealant technique (EST). Methods A total of 400 first permanent molars in 200 patients aged from 6 to 10 years were treated with LCDF in occlusal pit and fissure enamel-plasty sealant technique. The opposite permanent teeth treated with LCDF in occlusal pit and fissure conventional sealant technique (CST) were employed as the controls. The patients were followed up for 3 years. Results Follow-up for 3 years showed that there was no significant difference in preservation rate between the EST and the CST groups in the first year, but in 2-3 years, there was significant difference in preservation rate (P