Color Assessment On The Veneer Restorations Of Mimic-tetracycline Pigm Entation Teeth

Aesthetics is essential to the anterior teeth restoration and the color is oneof the most important aspect of the aesthetics. Porcelain laminate veneer isfavored because of its color-rendering properties and optical properties thatsimulate natural teeth. Porcelain laminate veneer possesses a favorable opaqueeffect and color matching on non-tetracycline teeth, but for tetracycline teeth,the masking capability of the veneer is limited and the lightness of therestoration decreases significantly, which may lead to poor aesthetic effects.As yet, the researches in this field mainly focused on the clinicalobservation of one certain method or comparison of several repair methods.There are no systemic research about the effects of the resin cement, abutmentteeth color and the thickness of core porcelain on the final color of tetracyclinediscolored teeth after porcelain laminate veneer restoration. Therefore, in thisstudy we established a tetracycline-based dental model and systemicallyassessed the effects of resin cement (including A1- and A3-shade of the RelyXveneer light-curing system, and light- and opaque-shade of Panavia F doublecuringsystem), abutment teeth color (including yellow, light gray, bright red, dark gray, dull red), and the core porcelain thickness of the veneer on the colorof IPS e.max porcelain veneer restorations for mimic-tetracyclinepigmentation teeth. In our investigation, the L*a*b* values were measured byspectrophotometers CM-700d/600d and the color differences(â–³E) werecalculatedThe results are listed as follows:1. The difference of the L*a*b* values among different resin cementgroups were significant(P<0.005). There was no significant difference betweenthe L*a*b* values of the control group and the opaqueshade of Panavia Fgroup. The color difference (â–³E) was lower than 1.5 only between the controlgroup and the opaqueshade of Panavia F group, but not among others.2. The L*a*b* values were significantly different(P<0.005) amongdifferent simulated background (abutment teeth). With the backgroundbrightness value decreased, compared with the control group, the L* valuedecreased greatly and the color difference(â–³E) value increased obviously. Itshowed that the color of the abutment teeth influenced the color of therestoration seriously, and the influence was the least when the abutment teethcolor was yellow.3. L*a*b* values were significantly different(P<0.005) among differentcore porcelain thickness. With the nuclear porcelain thickness thinning,â–³L*value and color difference(â–³E) value increased of experimental group. Thatindicate porcelain veneers masking ability trail off.In summary, resin cements, abutment teeth color and core porcelainthickness of veneers all have significant effects on the color aesthetics of theporcelain veneer restoration. Compared with other resin cements used in thisstudy, the Opaqueshade of Panavia F resin cement has better masking ability. The restorations possesses favorable as abutment teeth color is yellowmeanwhile it should choose preferable masking cements when abutment teethcolor is dark grey. As the thickness of the core porcelain increased, the maskingability increased greatly, but the thickness also affected the glossiness andtranslucency of the veneers. Therefore, the dentists should choose appropriateresin cements and porcelain veneers according to the patient's requirementsand the specific circumstances.