Effects of aging methods on microleakage of an adhesive system used as a sealant on contaminated surfaces

Abstract

This study evaluated the effects of aging methods on the microleakage of an adhesive system used for sealing pit and fissure surfaces. After acid etching, the occlusal surfaces of 60 permanent teeth were contaminated with 1mL of human plasma and then sealed with OptiBond dual cure, activated in the ramp mode (Optilux 501). The sample was then divided into eight experimental and a control groups. Aging was performed for 20 days in 5, 37, 55 and 5-55ºC (200 cycles/day) under water contact or not. After subjecting the specimens to the AgNO(3) technique, they were sectioned twice. Dye penetration was measured and the mean values were subjected to ANOVA. No group provided hermetic seal against dye penetration, even the control group (without treatment). Significant aging x water interaction effect (p=0.033) was observed. The group without water contact at 5ºC (p=0.015) showed the least dye penetration value. The results led to the main conclusions: 1) all groups showed dye penetration, even the control group; 2) storage teeth at 5ºC on dry condition provided the lowest degree of dye penetration; 3) in the presence of water, the temperature variations seem not to affect the microleakage values.

Characterization of aqueous silver nitrate solutions for leakage tests

“…The specimens were stored in distilled water at 37°C for 24 h 1 , 4 , 15 , 23 in a humidifier incubator (Nova Ética Ind & Com Ltda, Vargem Grande Paulista, SP, Brazil). After this period, each restoration was finished with aluminum oxide disks (Sof-Lex; 3M ESPE) of different grain sizes (medium, fine, and extra-fine), under constant water cooling 17 .…”

“…After immersion in the silver nitrate solutions for 2 h, the specimens were washed, immersed in a photographic developer (Eastman; Kodak Co, Rochester, NY, USA) for 8 h under fluorescent light, and then abundantly washed under running water 4 , 19 .…”

“…The dye penetration technique is one of the most used methods for assessing marginal seal 1 , 14 because it allows penetration of the substance to be verified in contrasting colors at the tooth-restoration interface, without requiring a chemical reaction or the use of radioactive materials28,29. In spite of the variety of dyes mentioned in the literature 7 , several authors have used chemical tracers 4 , 14 , 15 , 19 , 30 , such as 50% silver nitrate (w/v) with special frequency in microleakage assays, using different immersion times of specimens in the agent and different times to reveal the silver 3 , 7 , 19 . The amount and distribution of silver show the extent of damage at the material/ tooth interface, which can be measured by using various micro-investigation techniques 6 , 12 , 28 , 29 , 30 .…”

A 12-month clinical evaluation of pit-and-fissure sealants placed with and without etch-and-rinse and self-etch adhesive systems in newly-erupted teeth

“…In this clinical condition, this is very difficult to isolate tooth and applying rubber dam is also impossible 1,6 . In the early eruption stages of the permanent maxillary first molar, the distopalatal groove is in close vicinity, or even contacting gingival sulcus at the distal and palatal area.…”

Evaluation of the coefficient of thermal expansion of human and bovine dentin by thermomechanical analysis

“…For endodontically compromised teeth, these temperature changes are even more critical due to the lack of pain sensitivity and circulating fluids inside the pulp chamber, which make the tooth more susceptible to higher temperature differences and return more slowly to the mouth temperature. Even though this stress may not be strong enough to fracture these materials immediately, it has been postulated that any microscopic flaws present at the tooth-restorative material interface may have a tendency to propagate slowly over many cycles of such stress and thereby produce microleakage at the interface (21).…”