Effects of modeling liquid/resin and polishing on the color change of resin composite

At a Glance

Metadata	Details
Publication Date	2016-01-01
Journal	Brazilian Oral Research
Authors	José Augusto Sedrez-Porto, Eliseu Aldrighi Münchow, Lucas Pradebon Brondani, Maximiliano Sérgio Cenci, Tatiana Pereira‐Cenci
Institutions	Universidade Federal de Pelotas
Citations	37
Analysis	Full AI Review Included

6CCVD Technical Analysis: Surface Engineering for Enhanced Esthetic Stability in Composites

Executive Summary

This research paper underscores the critical role of surface finishing and interlayer material composition in the long-term esthetic stability of resin composites (RCs), directly validating the need for ultra-precision surface engineering capabilities offered by 6CCVD.

Core Finding: High-precision polishing is statistically essential for minimizing color change ($\Delta E^*$), rejecting the null hypothesis regarding the superiority of non-polished surfaces.
Surface Roughness Validation: Non-polished specimens developed a rough “crust complex,” facilitating severe staining. The research confirms the importance of surfaces below the critical threshold of 0.2 µm Ra for minimizing staining and biofilm adhesion.
Modeling Liquid Benefit: The application of a hydrophobic modeling liquid (SBMP) between composite layers significantly reduced overall color change ($\Delta E^*$), demonstrating enhanced chemo-physical stability within the material structure.
Material Degradation Focus: The study highlights that color stability is a direct function of controlling surface topography and limiting internal material hydrolysis caused by environmental exposure (red wine storage for 12 months).
6CCVD Value Proposition: The requirement for sub-micron surface control in this demanding dental application aligns perfectly with 6CCVD’s advanced polishing capabilities, offering SCD surfaces with roughness (Ra) less than 1 nm.

Technical Specifications

Hard data extracted from the experimental methodology and results. Note: $\Delta E^$ refers to the overall color change metric (CIELab system).

Parameter	Value	Unit	Context
Critical Roughness Threshold	0.2	µm	Threshold cited for bacterial plaque / biofilm formation
Staining Medium	Red Wine (Cabernet Sauvignon)	N/A	Storage environment for color stability testing
Staining Medium pH	3.6	N/A	High acidity challenging material stability
Alcohol Content (Volume)	14.5	%	Used in staining medium
Storage Temperature	37	°C	Simulating physiological oral environment
Curing Unit Irradiance	900	mW/cm²	Light activation protocol (LED)
Curing Time	20	s	Applied per surface (top and bottom)
Composite Layer Thickness	±0.5	mm	Used for incremental layering
Polishing Time (per disc)	15	s	Duration for each Sof-Lex disc stage
Clinically Perceptible $\Delta E^*$	> 3.3	$\Delta E^*$	Visual threshold for unacceptable color change
Highest $\Delta E^*$ Observed (12 Mo)	50.8 ± 2.0	$\Delta E^*$	Non-polished Control group
Lowest $\Delta E^*$ Observed (6 Mo)	13.9 ± 2.6	$\Delta E^*$	Polished SBMP group

Key Methodologies

A concise, step-by-step outline of the experimental procedure focusing on material preparation and treatment parameters.

Specimen Fabrication: Disc-shaped specimens (6 mm diameter x 2 mm thickness) were prepared by placing four increments of Filtek™ Z350 XT Resin Composite (RC) into silicone molds.
Modeling Liquid Integration: Half of the specimens (SBMP group) were prepared with an application of Scotchbond™ Multi-Purpose™ Adhesive (SBMP) between the RC increments. The control group received no SBMP.
Light Curing: Specimens were light-activated for 20 s on both top and bottom surfaces using a calibrated LED unit (900 mW/cm² irradiance).
Surface Finishing Division: Specimens were divided into two surface treatment subgroups (n=7): non-polished (no treatment) and polished.
Polishing Protocol: Polished groups underwent a sequence using Sof-Lex™ polishing discs (medium to extra-fine, 15 s each), followed by felt discs and Diamond AC II diamond paste.
Staining and Storage: All specimens were immersed in red wine at 37 °C for a total duration of 12 months, with weekly replacement of the staining medium.
Measurement and Analysis: Color parameters (CIELab*) were measured at baseline, 4, 6, and 12 months. Scanning Electron Microscopy (SEM) was performed on surfaces and cross-sections after 12 months to analyze topography and internal structure.

6CCVD Solutions & Capabilities

This research demonstrates that superior material performance in demanding environments (chemical exposure, thermal cycling, and wear) is fundamentally linked to surface quality and precision. 6CCVD is uniquely positioned to supply the materials, precision substrates, and engineering support necessary to replicate or advance research in advanced restorative materials and tooling.

Research Requirement	6CCVD Applicable Materials & Services	Technical Justification & Sales Opportunity
Extreme Surface Smoothness	Optical Grade Single Crystal Diamond (SCD) Wafers and Ultra-Polished Polycrystalline Diamond (PCD).	The study demands Ra < 0.2 µm. 6CCVD’s standard SCD polishing achieves Ra < 1 nm, providing a near-perfect surface finish essential for minimizing chemical degradation, staining, and bacterial adhesion in extreme biomedical applications.
Material Longevity & Inertness	High-Purity SCD or PCD substrates and thick diamond layers (up to 500 µm).	SCD/PCD offers exceptional chemical inertness and resistance to hydrolysis/wear, surpassing typical polymer composites. Our materials are ideal for creating durable dies, molds, or reference standards for evaluating dental wear and staining resistance.
Custom Abrasives & Tooling	Custom-sized Polycrystalline Diamond (PCD) substrates up to 125 mm diameter.	The experiment relied on diamond-based polishing tools. 6CCVD supplies the foundational MPCVD diamond wafers necessary for manufacturing high-performance, precision abrasive discs and slurries used in clinical finishing.
Specialized Sensor Integration	Boron-Doped Diamond (BDD) thin films (SCD or PCD base) with Custom Metalization (Ti/Pt/Au/W).	Although the paper focused on esthetics, future dental research may require electrochemical monitoring or embedded sensors. 6CCVD offers BDD electrodes and in-house metalization services (Au, Pt, Ti, etc.) essential for bio-sensing and monitoring corrosive environments (like pH 3.6 wine exposure).
Custom Geometries	Custom Dimensions and Laser Cutting Services.	Whether for replicating standard test dimensions (e.g., 6 mm discs) or engineering complex micro-molds and jigs for stratification techniques, 6CCVD offers precision cutting on wafers up to 125 mm (PCD) and substrates up to 10 mm thick.
Expert Consultation	Access to 6CCVD’s in-house PhD Material Science and Engineering Team.	Our team can assist with material selection for similar projects focused on Aging and Dental Materials, optimizing diamond film thickness (0.1 µm to 500 µm) and structure to ensure maximum chemical resistance and mechanical integrity under simulated oral stress.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We ship globally (DDU default, DDP available) to support your most demanding research projects.

View Original Abstract

Modeling liquids/resins have been used to build up resin composite (RC) restorations, although there is a lack of information regarding their effects on the color stability of the latter. Therefore, the purpose of the present study was to evaluate the effects of the presence of modeling liquid between layers of RC and the finishing/polishing state of the material on color change in specimens exposed to red wine staining over time. Specimens were prepared by placing four increments (±0.5 mm thick) of RC (Filtek™ Z350 XT, 3M ESPE) into molds; half of which were prepared by applying modeling liquid (Scotchbond™ Multi-Purpose™ Adhesive, SBMP, 3M ESPE) between the layers of RC, whereas the other half were prepared without SBMP (control). Light-activation was performed after application of the final RC layer using a light-emitting diode (Radii, SDI) curing unit with an irradiance of 900 mW/cm2 for 20 s. Each group was divided according to the surface finishing protocol (n = 7): nothing (non-polished) or polishing with Sof-Lex™/diamond paste (polished). Initial colors of the specimens were evaluated with a digital spectrophotometer and the CIELab* color system. The specimens were stored in wine (37°C) for 12 months, and the color measurements were reassessed after 4, 6, and 12 months of storage. Scanning electron microscopy (SEM) analysis was performed at the end. Data were analyzed using ANOVA and Tukey’s test (α = 5%). The presence of SBMP resulted in lower overall color change of the RC as compared with the control. The non-polished specimens exhibited a significantly higher color change than the polished specimens. SEM images corroborated the previous findings. In summary, the use of modeling liquid between layers of RC shows potential for application to reduce or delay the staining process of RC over time. Moreover, polishing is essential to provide increased color stability of the RC restoration.

Tech Support

Original Source

DOI: https://doi.org/10.1590/1807-3107bor-2016.vol30.0088

References

2011 - Cuspal deflection and depth of cure in resin-based composite restorations filled by using bulk, incremental and transtooth-illumination techniques [Crossref]
2012 - Depth of cure and mechanical properties of nano-hybrid resin-based composites with novel and conventional matrix formulation [Crossref]
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2013 - The effect of a modeling resin and thermocycling on the surface hardness, roughness, and color of different resin composites [Crossref]
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