An In Vivo Spectrophotometric Analysis of Gingival Acrylic Shade Guide

Abstract

Selecting shades of acrylic gingival restorative material is challenging. This study examined the shade appropriateness of five acrylic gingival restorative materials. The color was analyzed using an intraoral spectrophotometer (Crystaleye®, Olympus). The gingival color of maxillary incisors for eighty-nine patients was measured. CIELAB color coordinates (L*, a* and b*) were obtained, and the color difference ∆E (Coverage Error: CE) between shade tabs and natural gingival color of patient samples for each shade guide system were compared. Repeated ANOVA and post hoc analyses with Tukey′s HSD were performed. There was a significant difference among the mean minimum CEs of the tab sets (p < 0.01). GC Acrylic (CE = 5.89 ∆E ± 2.97) and Lucitone 199® (CE = 6.55 ± 3.33) groups exhibited CEs significantly lower than all other groups (all p < 0.001). The IvoCap® system exhibited the highest CE (10.78 ± 3.80), significantly greater than all other groups (p < 0.001). No significant differences were observed based on sex (p = 0.055) or ethnicity (p = 0.327). The GC Acrylic and Lucitone 199® shade guides showed the lowest CEs. All guides had coverage errors above 5.89 ∆E, which is larger than ∆E thresholds of acceptability. Of the materials evaluated in this study, GC Acrylic and Lucitione 199® are best able to reproduce the clinical appearance of the gingival tissue. Many patients have tissue that cannot be reproduced accurately with currently available materials.

Determination of the degree of conversion, the diffuse reflectance, and the color stability after different aging processes of gingiva‐colored composite resins

“…Color changes differ according to aging processes and gingiva‐colored composite brands. A study reported that different thresholds could be considered to evaluate color changes of the gingiva‐colored materials 29 . Gingival color might differ across a wider range compared to tooth color and there is no consensus on the gingival color threshold 1 .…”

“…CIELAB color space (CIE: International Commission on Illumination) was used to determine the color differences. 29 The primary parameters of color (L* lightness from black (0) to white (100), a* amount of green (-) and red (+), b* amount of blue (-), and yellow (+)) of all specimens in the CIELAB (ΔE* ab ) total color differences were recorded before and after aging procedures with a colorimeter on white baseline (L* = 98.2, a* = −0.14, b* = −0.24) (Minolta CR-321, Japan). The colorimeter was calibrated at the beginning and then after every 20 measurements as per the manufacturer's instructions.…”

“…A study reported that different thresholds could be considered to evaluate color changes of the gingiva-colored materials. 29 Gingival color might differ across a wider range compared to tooth color and there is no consensus on the gingival color threshold. 1 The present study used the gingival color threshold based on the study of Paravina et al 31 As per this context, for mean ΔE * ab values, all gingiva-colored composites after UV treatment, only AG after hydrothermal aging treatment, and only GR after autoclave aging treatment were in the AT range.…”

Degree of Standardisation in Ceramic Gingival Systems

“…The literature on gingival colour is not as developed as the research that has examined dental colour [52,[75][76][77][78]. Most publications on gingival colour have focused on calculating the acceptability and perceptibility thresholds [55,79,80], designing optimal gingival guides using mathematical models of in vivo colour readings for healthy gingiva [50,53], studying the gingival colour coordinates of distinct populations [52,81,82], and the coverage errors of gingival shade guides [54,75,78,[83][84][85][86]; however, there are no publications that tackle the fundamental issue of standardising gingival colours-even those with similar names-or that involve the production of new gingival colours using mixtures of basic gingival colours. This has led to significant limitations when it comes to communicating gingival colour, as there are no universally accepted reference resources for gingival colour, and the main manufacturers have developed colour systems without scientific publications explaining the rationale behind them or justifying the intra-and inter-system colour differences between the gingival colours.…”