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Color Variability of laminate veneers
Transcript of Color Variability of laminate veneers
Under the supervision of Prof./ Amal Ezz El Din
Faculty of Dentistry, Pharos University, Alexandria,Egypt .
Presented by :
Aim of the Study
Materials and Methods
Since its introduction in 1938 ,
laminate veneer restorations have proven to be durable and aesthetic restorative procedure for treatment of teeth in the front area of the mouth.
Laminate veneers are more conservative than crowns and maintain the bio mechanics of an original tooth with a success rate of approximately 93% over 15 years of clinical use .Because of that the indications of this procedure expanded to a point where its use is now a common practice in dental clinics .(1)
The evolution of materials, ceramics, and adhesive systems permits improvement of the aesthetic of the smile and the self-esteem of the patient.
Clinicians should understand the latest ceramic materials in order to be able to recommend them and their applications and techniques, and to ensure the success of the clinical case.
The consumption of coffee and soft drinks, for example, has a high prevalence in the contemporary society, especially in industrialized countries. It has been demonstrated that surface discolorations in composite resins are related to hygiene, eating habits and smoking .
The maintenance of the esthetics of a restoration is therefore related to the patients’ habits and lifestyle.(2)
Discoloration in resin composites can be extrinsic discoloration, or intrinsic (subsurface) discoloration. Extrinsic staining occurs mostly due to either picking up stains or absorbing the stain, while the intrinsic staining occurs due to dispersion of stain into the resin materials followed by a chemical reaction.
The staining ability of the composite is related to resin matrix, percentage of filler particles,adsorption and absorption of stains,type of staining solution, and chemical interactions between composites and the stains.(3)
Evaluation of the color stability of different types of laminate veneers materials upon exposure to aggressive staining solutions like
(coffee , tea and cola) over time.
Aim of the Study
Materials and Methods
Surface-modified zirconia/silica with a median particle size of approximately 3 microns or less
Non-agglomerated/non-aggregated 20 nanometer surface-modified silica particles
The filler loading is 82% by weight (68% by volume)
• BIS-GMA, UDMA, BIS-EMA, PEGDMA and TEGDMA
The microstructure of IPS e.max Press
consists of lithium disilicate crystals
(approx. 70%), Li2Si2O5, embedded in a glassy
Lithium disilicate is the main crystal phase
and consists of needle-like crystals.
The crystals measure 3 to 6 μm in length.
Split Teflon Mold
Glass Slab Slides
Plastic filling instrument
LED = light emitting diode (LED)
IPS e.max® Press ingots
Renferd vaccume mixer
IPS® Investment Ring System
IPS® PressVest Speed,
Programat® EP 3010
E-max press invex liquid “hydroflouric +nitric acid
Grouping of the test specimens
A total of 27 Disc Samples were assessed (n = 9 )for each group
They were prepared in A2 shade,
Preparation of test specimens
Composite resins were injected into Teflon moulds (10 mm in diameter and 2 mm in depth) and placed over a glass plate. Finger pressure was applied to the glass plate to expel excess materials and create a smooth surface. The composite resins were then polymerized using a LED light‐curing unit for 40 s to allow thorough polymerization. The discs were removed from the moulds, stored in water for 24 h to complete polymerization
Initial reading was then taken .....
Three different beverages were used in this experiment:
(1) tea (Lipton, Yellow Label Tea, Lipton, Rize, Turkey).
(2) Coffee (Nescafe Classic, Nestle, Switzerland) .
(3) Coca-Cola .
Tea solution was prepared by immersing one prefabricated tea bags (2 g ) into 100 ml of boiling distilled water
A 1.6 g of coffee powder was dissolved in 100 ml of boiling distilled water , After 10 min of stirring, the solution was filtered through a filter paper.
100 ml of Coca-Cola
• Test tubes were covered and placed in an incubator at 37C.
•The solutions were changed daily for one week.
According to Guler, et al(2005) the average time for
consumption of 1 cup of coffee is 15 min, and among coffee drinkers, the
average consumption is 3.2 cups per day. Therefore,
15 days of storage simulated consumption of the drink over 1 year.(4)
IPS e.max® Press
Materials used in the study :
It Consists of dimethacrylate and TEGDMA (22 wt%). The fillers include barium glass, ytterbium trifluoride, silicon dioxide and mixed oxide (76 wt% or 60 vol%).
Additives, initiators, stabilizers and pigments are additional contents (2 wt%). The particle size of inorganic fillers is between 0.04 and 7 µm.
Within the limitations of this In-vitro study
1 - Aging the laminate veneers in Staining solutions had a significant influence on the color stability of the three types of laminate veneers used ,their color change in these staining agent was visually perceptible as well as clinically unacceptable
2- For all the materials tested, their color change in staining agents ranked in this increasing order: water ＜ cola ＜ coffee<tea
3-IPS emax ceramic laminate veneers are superior to direct composite laminate veneers. They are considered the materials of choice as they exhibited better color stability because of being less affected by the colored beverages.
4-Nano-hybrid composite materials offer an attractive second option with the economical benefits of reduced visits and chair time while achieving good control of aesthetics and the promise of limited staining.
Coloring beverage preparation
Currently, spectrophotometers have been used as a useful tool to measure discoloration of restorations using the CIE Lab system.
This system inherits the advantage of being repeatable, sensitive,objective, universally accepted, and can measure small color differences.
1- Crumpler DC, Heymann HO, Shugars DA, Bayne SC, Leinfelder KF. Five-year clinical investigation of one conventional composite and three microfilled resins in anterior teeth. Dent Mater. 1988;4(4):217-22.
2- Khokhar ZA, Razzoog ME, Yaman P. Color stability of restorative resins. Quintessence Int. 1991;22(9):733-7.
3-Asmussen E, Hansen EK. Surface discoloration of restorative resins in relation to surface softening and oral hygiene. Scand J Dent Res. 1986;9(2):174-7.
4-Guler AU, Yilmaz F, Kulunk T, Guler E, Kurt S. Effects of different
drinks on stainability of resin composite provisional restorativematerials.
J Prosthet Dent. 2005;94(2):118-24.
Preparation of IPS E-max speciments
Micro Nano E-max
FiltekTM Z250 XT
[3M ESPE, St. Paul, MN, USA]
Ivoclar Vivadent AG FL-9494 Schaan/Liechtenstein
For the preperation of composite resin specimens
For the preperation of IPS.eMax specimens
Specimen after finishing and polishing :
Sub-grouping of test specimens
The color values were recorded using a digital spectrophotometer
(Vita Easy shade, Compact, Vita, Zahnfabrik, Bad Sackingen, Germany).
The specimens were positioned on a white background to prevent potential absorption effects during color measurements.
Three measurements were taken with the active point of the spectrophotometer in the center of each disc.
The device automatically averaged the three readings, and this average reading was subsequently used for data analysis.
Before each series of measurements, the spectrophotometer was calibrated according to the manufacturer recommendations where “L” namely white-black, “a” red-green, “b” yellow-blue.
Representative specimens after removal from different beverages :
Two-way analysis of variance（ANOVA）was used to
evaluate the effects of material type and staining
solutions on color change, including the possibility of interaction between the two factors using a statistical
software（SPSS for Windows, Version 20.0.SPSS
Inc., Chicago, IL, USA）.
Then, the means were compared by Tukey’s HSD test P≤0.05）.
Initial L , a, and b for the three materials " control groups (specimens stored in distilled water )"
Final L , a, and b for the three materials " (specimens stored in Tea )"
Final L , a, and b for the three materials " (specimens stored in Coffee )"
Final L , a, and b for the three materials " (specimens stored in Cola )"
TABLE (2) SHOWING THE MEAN ± SD OF THE COLOR VARIABILITY( ΔE) OF THE THREE STUDIED MATERIALS
TABLE (1) SHOWING THE EFFECT OF THE DIFFERENT STAINING SOLUTIONS ON ( ΔE) EACH MATERIAL