In vitro microleakage of a fissure sealant polymerized by either a quartz tungsten halogen curing light or a plasma arc curing light

Effect of new light curing units on microleakage and microhardness of resin sealants

To determine new developed light curing units with shorter curing times effects on microleakage and microhardness values for resin fissure sealants. Resin filled sealant (UltraSeal-XT), resin unfilled sealant (Delton Type-II) and ormocer-based sealant (Admira-Seal) were light cured with a quartz-tungsten-halogen (QTH), two LED light and a high power LED. Two hundred and forty extracted human molars were randomly allocated into four groups according to used light-curing unit and three subgroups were formed for three different fissure sealant materials. Specimens were immersed in 0.5% basic fuchsin for 24 h, sectioned and examined under a stereomicroscope, and scored for marginal microleakage. Knoop hardness number (KHN) readings were measured after 48 h. Statistical analyses of test were found in significant difference both microleakage and microhardness values between the various light curing units. The time saving approaches in the curing light were determined higher microhardness, although it was found in higher microleakage.

Micro-leakage of a Fissure Sealant Cured Using Quartz-tungsten-halogen and Plasma Arc Light Curing Units

Background and aims. Newer curing units such as plasma arc can polymerize the sealants in much shorter curing times. The aim of this study was to compare the effect of two different curing units on the micro-leakage of a fissure sealant material. Materials and methods. Sixty two extracted premolars without caries were randomly divided into two groups of 31 samples. Occlusal surfaces of all teeth were cleansed. Then, teeth surfaces were etched by 37% phosphoric acid. After rinsing and drying, occlusal surfaces of teeth were sealed by a fissure sealant. The sealant was then cured using either a halogen light curing unit or a plasma arc curing light. After sealing, the teeth were thermocycled for 500 cycles. The teeth were then sectioned and examined for micro-leakage. Statistical analyses were performed with Mann-Whitney test. Results. There was no significant difference between two groups regarding micro-leakage (P = 0.42). Conclusion. Results showed that there was no significant difference between two different curing units. Therefore, plasma arc unit might be a useful alternative for sealant polymerization.

Evaluation of microtensile bond strength of different fissure sealants to bovine enamel

BACKGROUND

The aim of this study was to evaluate the microtensile bond strength (μTBS) of a new fissure sealant and compare it with conventional sealants which are applied to enamel alone, and also with self-etch and etch-and-rinse adhesives.

METHODS

Enamel specimens were prepared and randomly distributed into three groups according to fissure sealant (Aegis, Helioseal F, Helioseal Clear). Each group was then subdivided according to adhesive system (Clearfil S3, Single Bond, no adhesive). A universal testing machine was used to measure μTBS, and data were analysed using one-way ANOVA and Tukey's tests.

RESULTS

μTBS values for all Aegis subgroups were significantly lower than for comparable Helioseal F and Helioseal Clear subgroups (p < 0.05). No differences were observed in μTBS of Helioseal F and Helioseal Clear (p > 0.05). In the Helioseal Clear group, μTBS values for Single Bond were significantly higher than for Clearfil S3 (p < 0.05). However, no significant differences were found between the μTBS values of the adhesive subgroups in the Aegis or Helioseal F groups (p > 0.05).

CONCLUSIONS

Sealant μTBS values may be affected by material content. The addition of an adhesive may improve μTBS values of sealant to enamel.