Resin Composite Technique Reduces Dark Halo Effect
Partial bevel coverage with opaque resin and the internal mirror technique effectively reduce dark halo visibility in class III restorations, Cureus reported.
A dark halo around class III resin composite restorations frequently compromises anterior dental esthetics due to light wave interference. This optical phenomenon occurs when light waves undergo destructive interference, making a restoration visibly noticeable despite correct shade matching.
To evaluate strategies preventing this contour perception, researchers tested eighty bovine incisors divided into eight groups based on bevel extensions of 1.0mm or 2.0mm. Restorative approaches included no bevel coverage, partial coverage at 50% or 75% using opaque dentin shade resin, and the internal mirror technique.
The study found that the internal mirror method, alongside 50% and 75% bevel coverage, performed significantly better than restorations with no opaque resin coverage. These specific techniques mask the dark halo effectively by either reflecting incident light or compensating for destructive wave interference.
Bevel extensions show no significant difference in esthetic outcomes
Standardized C-shaped class III cavities were prepared on eighty bovine incisors using diamond burs and restored with Filtek Supreme resin composite from Solventum. The evaluations utilized grayscale digital cross-polarized pictures assessed by two blinded, calibrated examiners using a three-point visual scale.
Statistical evaluations using the Kruskal-Wallis test followed by the Dunn test showed that bevel extensions of 1.0mm and 2.0mm did not yield statistically significant differences in esthetic outcomes. Shade A2E served for translucent enamel layers while shade A2D provided opaque dentin coverage.
The internal mirror technique utilized a translucent resin lingual wall, a white opaque dentin layer, and a darker body resin layer before final polishing. Restorations were finished after seven days of water storage and analyzed following an additional 14 days in deionized water at 37°C.
Common Questions on Class III Restorations
What causes the dark halo around class III restorations?
Destructive light wave interference creates the dark halo effect when overlapping light wave peaks and valleys decrease amplitude around resin composite margins.
How does the internal mirror technique work?
This method employs an internal white opaque resin composite layer to reflect incident light and increase the value of the adjacent enamel region.
Did bevel size affect the visual appearance of restorations?
The study determined that bevel extension sizes of 1.0mm and 2.0mm had no significant influence on the esthetic results of the restorations.
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