Feldspathic Veneers Research Articles

A comparative evaluation of shear bond strength between feldspathic porcelain and lithium di silicate ceramic layered to a zirconia core- An in vitro study.

BackgroundThe bond strength between the zirconia core and ceramic veneer is the weakest component in the layered structure. Delamination of veneering ceramic is reported as one of the most frequent problems associated with Veneered Zirconia restorations. The aim of this study is to compare the shear bond strength of lithium di silicate porcelain to that of feldspathic porcelain on a zirconia Substrate. Material and MethodsTwo groups (group A and B) of zirconia blocks with each group having 20 samples were fabricated according to Schmitz Schulmeyer method. Group A (n =20 ) samples were veneered with feldspathic veneering porcelain and Group B (n=20) samples were veneered with heat pressed lithium disilicate ceramic. The fabricated samples were then evaluated for shear bond strength in Universal Testing Machine. The values were then statistically analyzed using independent sample t-test. ResultsResults of the current study showed that mean shear bond strength of feldspathic porcelain 11.40±1.29 MPa is comparatively lower than the mean shear bond strength of the lithium disilicate group 18.81±1.76 MPa. The statistical analysis indicated that (p value<0.01) there is a statistically significant difference in the shear bond strength between the two groups. ConclusionsThe heat pressed lithium disilicate veneering materials has a better shear bond strength compared to feldspathic veneering ceramic material when layered to a zirconia core and it can be used as a viable alternative material to feldspathic porcelain layering material in bilayered zirconia restorations. Key words:Zirconia, bilayered ceramics, lithium disilicate , shear bond strength, ceramic chipping.

Long-term fracture load of all-ceramic crowns: Effects of veneering ceramic thickness, application techniques, and cooling protocol.

BackgroundTo evaluate, in vitro, the effects of the cooling protocol, application technique, and veneering ceramic thickness on the fracture resistance of ceramic crowns with Y-TZP frameworks. Material and Methods80 frameworks were made from zirconia by the CAD/CAM technique and divided into 8 groups (n = 10) according to the factors: “application technique” (stratified-L and pressed -P), “thickness” (1 mm and 2 mm), and “cooling protocol” (slow-S and fast-F) of the feldspathic veneering ceramic. After, all crowns were cemented over G10 preparations with resin cement (Panavia F, Kuraray), mechanically cycled (2x106 cycles, 200 N, 3Hz), and subjected to the axial compression resistance test (0.5 mm/min, 10 kN). The data (N) underwent descriptive statistical analysis by 3-way ANOVA and Tukey’s test (5%). Fracture analysis was performed to determine the possible origin of failure. ResultsThe factors “cooling protocol” (P=0.0058) and “application” technique (P=0.0001) influenced the fracture resistance of the crowns. For pressed veneer technique, the P2S (4608.9±464.5). A presented significantly higher results than that P2F(3621.1±523.0)BCD (Tukey’s test). For the stratified technique, this difference was not observed (P>0.05). The thickness of the veneering ceramic was not significant regardless of the cooling protocol and technique (P>0.05). The predominant failure mode was chipping of the ceramic veneer originating in the subsurface. ConclusionsThe pressed technique, used with a slow-cooling protocol, leads to the best outcome for the veneering of all-ceramic crowns. Key words:Zirconia, ceramics, cooling protocol, thickness, application technique.

The art of minimal tooth reduction for veneer restorations

AbstractMinimal tooth reduction is crucial for the long-term success of adhesive restorations. It has been proven that bonding to enamel is more predictable in obtaining better long-term success than dentin due to its higher percentage of mineral content. The diagnostic wax-up and subsequent mock-up are the first diagnostic tools available to evaluate discrepancies between current and ideal tooth proportions. The intraoral mock-up provides the patient a tactile and visual evaluation of the size, shape, and shade of the proposed final restorations, and at the same time, the clinician can evaluate the smile line, lip support, phonetics, and occlusion. During the tooth preparation, the mock-up provides a reduction guide to the clinician to achieve the minimal required reduction for the final restoration avoiding the over-reduction and dentin exposure. This clinical report shows feldspathic veneer restorations provided with conservative tooth preparation. The long-term success of the restoration requires following well-defined protocols for restorative material selection, conservative tooth preparation, total isolation with rubber dam, and bonding ceramic protocols.

Improving the wear performance of feldspathic veneering porcelain by ion-exchange strengthening

ObjectivesThe present study examined the effects of Na+→K+ ion-exchange on the wear performance of feldspathic veneering porcelain. MethodsBar and disk specimens were prepared using IPS classic as the feldspathic veneering porcelain. After ion-exchange by immersion of the specimens in melted KNO3 at two temperatures for different time-periods, the bars were tested for flexural strength and Vickers surface hardness. The disks were paired with zirconia antagonists and tested with a pin-on-disk tribometer with 10 N for 70☓104 wear cycles in artificial saliva. Wear analysis of the porcelain and zirconia was performed using 3D profilometer and analysed with one-way analysis of variance and Tukey’s post-hoc pairwise comparison procedures. Worn surfaces were examined with scanning electron microscopy. ResultsThe feldspathic veneering porcelain exhibited strong time-dependent wear behaviour, with typical running-in and steady wear stages. Ion-exchange treatments at 380 °C and 440 °C both enhanced the mechanical properties, decreased the wear rates of running-in wear and steady wear. The wear performance of porcelain treated by ion-exchange at lower temperature (380 °C) was improved significantly, especially reducing the wear rate of the running-in stage. ConclusionA thicker ion-exchange layer with less stress relaxation may be obtained by ion-exchange at lower exchange temperature for a long processing time. Such a protocol improves the wear performance of the porcelain effectively. Clinical significanceRestorations with veneering porcelain may fail prematurely due to excessive wear. It important to improve the wear performance of the porcelain. Ion-exchange has the potential to strengthen dental veneering porcelain. Understanding the effect of ion-exchange on the wear performance of porcelain provides insight improving the wear performance of these restorations.

Influence of Pre-Curing Different Adhesives on the Color Stability of Cemented Thin Ceramic Veneers.

The objective was to evaluate the color stability of thin ceramic veneers as a function of the curing mode (with and without pre-cure) of different adhesive systems applied to the internal surface of ceramics. Five adhesive systems (Scotchbond Multi-Purpose, Single Bond Universal, Gluma 2 Bond, Ambar, and Ambar APS) and photo-cured resin cement (Allcem Veneer) were used for cementing 0.6 mm-thick feldspathic veneers (Mark II) on composite resin substrates (Charisma Diamond). The groups, according to adhesive system, were divided into two subgroups (n=10): i) adhesive and resin cement were polymerized separately (pre-cure of the adhesive), ii) adhesive and resin cement were polymerized simultaneously. The CIELab color parameters were determined with a spectrophotometer at 24h (baseline), 7 days, 30 days and 12 months. Data were analyzed by two-way ANOVA and Tukey's test (α=0.05). The results indicated statistically significant differences for adhesive systems and time. The mode of curing of the adhesive system was not statistically significant: pre-cured adhesives (2.6±1.3) and not pre-cured adhesives (2.8±1.4). For the adhesives, ΔE values varied in the following order: Ambar-APS (1.6±0.5) < Scotchbond Multi-Purpose (2.6±1.2) = Gluma 2 Bond (2.7±1.2) = Ambar (2.9±1.2) < Single Bond Universal (3.5±1.5). For time, ΔE values were: 7 days (1.7±0.7), 30 days (3.5±1.2) and 12 months (2.9±1.3). It can be concluded that the different adhesive systems used for cementing thin ceramic veneers influenced the final color of the indirect restorations. The adhesives curing mode did not present a significant effect in the color stability of thin ceramic veneers.

Fluorescence of feldspathic ceramics: in vitro pilot study

Introduction: Ceramic veneers color is determined by the color and thickness of the ceramic, the cement and dental substrate color [1,2]. Changes in the thickness of feldspathic veneers, as well as the cement used, drastically influence the final color of the restoration [3]. Fluorescence is the optical property responsible for the perception of tooth vitality [4]. In a tooth, this optical property is mainly determined by dentin as it has more collagen (organic matter), which contains fluorescence-releasing amino acids, such as tryptophan, providing three times the fluorescence of enamel [5,6]. Aim of the study: Fluorescence emission evaluation of feldspathic ceramics using different cement colors as well as different ceramic thickness. Materials and methods: Feldspathic ceramic CEREC blocks (color A2) were cut with a manual microtome at a speed of 450 rpm with refrigeration to obtain 40 samples with a thickness of 0.5 and 0.8 mm. Filtek Supreme XTE Body composite resin discs with a thickness of 1mm [7] were produced using a resin frame. The discs were polymerized with a light-curing Elipar S10 Led. Surface treatment of the ceramic was carried out according to the manufacturer’s instructions. Ceramic samples were cemented to the composite resin discs with Relyx Veneer B0,5 / white or with Filtek Supreme XTE Body color A3 (previously heated in a resin oven). The cementation of the groups was done with a constant force of 50 Newtons for 60 seconds and polymerized for 40 seconds with Elipar S10 Led photopolymerizer. Fluorescence spectra were obtained on a SPEX Fluorolog2I2I spectrofluorometer at a wavelength of 380 nm and at room temperature. Results: An increase in thickness intensified the emission of fluorescence. The cementation material used in the study didn’t show statistically significant differences in fluorescence emission intensity when used in two different thicknesses (p = 0,378). Nonetheless, significant differences (p < 0.001) were found between the RelyX and Filtek group for each thickness. Discussion and conclusions: Fluorescence emission value is higher for the thicker group in the RelyX because this cementing material does not have components that add to the emission of fluorescence by the ceramic itself. The ceramic, having a greater thickness, presents a greater concentration of components that are able to emit fluorescence, which allows greater emission of fluorescence than the cementing material in use, such as in the study of Volpato et al. [8]. Like in the study by Pereira in 2015 the choice of different resin cements and ceramic thickness has to be taken into account when planning a case [9].

Rata de supravieţuire a faţetelor feldspatice versus cea a faţetelor presate

Rata de supravieţuire a faţetelor feldspatice versus cea a faţetelor presate

A Review on Translucent Zirconia.

Zirconia is suggested in many clinical situations due to acceptable biocompatibility, lower price compared with gold restorations, and better appearance than traditional metal ceramic restorations. New translucent monolithic zirconia has been developed to merge strength with improved tooth-colour matching. This work aims to review relevant articles on new translucent zirconia restorative materials. The published articles on translucent zirconia were searched through PubMed, Medline, Google scholar, and indexed journals using the following keywords: translucent zirconia, transparent zirconia, and tooth colored zirconia. The most relevant articles were selected and reviewed. Introduction of translucent zirconia, has brought the advantages such as less tooth preparation, biological compatibility, high strength, good mechanical properties, and less antagonist wear. However, the effects of altering material constituents to increase translucency on properties such as phase transformation and low temperature degradation may warrant further investigations. Translucent zirconia can be prescribed in many clinical situations and may provide less complicated procedures compared with the production of multilayer restorations of opaque zirconia cores and translucent feldspathic veneers. This may otherwise decrease fabrication time and defects, improve biological properties, reduce abutment tooth reduction, and result in less antagonist tooth attrition.

Full Mouth Rehabilitation of a Patient with Bruxism using Implant and Tooth-supported Monolithic Zirconia with Feldspathic Veneers

Full Mouth Rehabilitation of a Patient with Bruxism using Implant and Tooth-supported Monolithic Zirconia with Feldspathic Veneers

Complete rehabilitation of compromised full dentitions with adhesively bonded all-ceramic single-tooth restorations: Long-term outcome in patients with and without amelogenesis imperfecta

ObjectivesThis clinical follow-up evaluated the long-term outcome of full-mouth rehabilitations with adhesively bonded all-ceramic restorations in patients suffering from amelogenesis imperfecta (AI) or affected by extensive tooth wear including a loss of the vertical dimension of occlusion. Materials and methodsIncluded for evaluation were all patients treated with adhesively bonded monolithic single-tooth restorations made of silicate or lithium disilicate ceramics; allowing a maximum four missing teeth and a facial feldspathic veneering of LDS anterior crowns. After treatment, patients have been enrolled in a recall program for dental check-ups including quality assessment of the restorations. Patients answered the oral health impact profile (OHIP-14) at their last visit. ResultsSeventeen patients (mean age = 35 ± 18 years) were observed up to 16.5 years (mean: 6.2 ± 3.8 years). 12 out of 450 restorations failed due to core fracture (n = 7), tooth fracture (n = 2), one secondary caries, one chip-off grade 3, and one fixed dental prosthesis due to discomfort. The overall mean survival rate of the single-tooth restorations was estimated 99.4% at 5 and 91.4% at 10 years. The overall mean success rate was estimated 92.6% at 5 and 81.4% at 10 years, mainly due to chip-offs and crack formation (27 out of 31 relative failures). The mean annual failure rates (AFR) range between 1.5 and 2% over the years, but non-AI patients were affected more frequently by early technical complications in the facial veneering of anteriors, resulting in an AFR ranging between 5.2 and 4%. Quality assessment revealed stable color, form and marginal integrity in all patients up to ten years. The distribution of OHIP values is comparable to the representative sample of healthy patients. ConclusionAdhesively bonded single-tooth restorations provided a high clinical quality in the long-run. However, while the survival and success were excellent in AI patients, restorations in non-AI patients were affected by a higher complication rate, likely related to a higher risk profile due to a history of bruxism and tooth wear.

Wettability of zirconia by feldspathic veneer in dental restorations: Effect of firing atmosphere and surface roughness

Yttria-stabilized zirconia (YSZ) has been widely used in dental applications due to its excellent properties. However, chipping of fused feldspathic veneers on the zirconia cores is prone to limit the use of YSZ in all-ceramic dental restorations. The aim of this study was to investigate the effect of some processing parameters such as roughening the core surface and the atmosphere in which the feldspathic veneer was fused on the dental zirconia core.In order to address possible reasons of the chipping issue, the wetting behavior of a molten veneer on a zirconia core was evaluated using a sessile drop method at 990°C for 0–120min. The results showed the non-wetting behavior of the materials as the contact angles was measured to be >90° at conventional processing conditions. By varying some processing parameters such as surface roughening or firing atmosphere, it was found that these factors had huge effects on the wettability. The results showed that the melt veneer had little tendency to spread on the rougher zirconia surfaces. In addition, the firing of the feldspathic veneer in vacuum significantly decreased the wetting compared with that of in the air.

Esthetic rehabilitation with minimally invasive feldspathic ceramic veneers: 30 months of clinical follow-up

Diastemas among maxillary incisors and gingival contour disharmony are common findings among patients in dental practice. Ceramic veneers are indicated for esthetic rehabilitation of anterior diastemas due their predictable results, optical characteristics, fracture resistance and tooth structure conservation. However, because it is a friable material and have a brittle behavior, fractures occurrences are related to trauma, oclusal overload, parafunctional habits and material fatigue. This article describes 30 months follow-up of an esthetic and functional rehabilitation diastemas closure using feldspathic veneers associated with periodontal surgery and a ceramic repair with composite resin. Gingivectomy and frenectomy needs were found and the surgical procedures performed guided by new anatomic aspects of the crowns. Mock-up was performed after waxing and reverse planning. All anterior teeth underwent minimally invasive preparation. Feldspathic ceramic veneers were made, tried using try in paste and luted with light-cure resin cement. After 24 months, a fracture occurred on the right maxillary canine veneer. The ceramic restoration repair was performed with nano-hybrid composite resin, after the conditioning with 5% hydrofluoric acid, 37% phosphoric acid and silane couple agent. The combination between ceramic veneers and gingivectomy enables to obtain conservative treatments and esthetic success. After six months of the repair, resulting 30 months of follow-up, the anterior restorations were aesthetically and functionally satisfactory.

A prospective evaluation of zirconia anterior partial fixed dental prostheses: Clinical results after seven years

Statement of problemBecause of the high mechanical strength of zirconium dioxide, the metal in fixed partial prostheses can now be replaced. However, the material is susceptible to aging or hydrothermal degradation and to chipping of the feldspathic veneer. PurposeThe purpose of this prospective study was to evaluate the survival (without failure) and success (survival without any complication or failure) rate and clinical efficacy of anterior zirconia partial fixed dental prostheses. Material and methodsTwenty-seven anterior partial fixed dental prostheses of 3 to 6 units were fabricated. All participants were examined after 1 month and 6 months, then annually for 7 years. ResultsThree partial fixed dental prostheses failed and had to be removed: 2 because of secondary caries, which increased failure significantly (P=.001) and 1 because of severe chipping. Six partial fixed dental prostheses had complications: 2 debonded, 3 had chipping, and 1 had periapical pathology. All veneer porcelain fractures occurred in 6-unit fixed partial prostheses (P=.002). The clinical success rate was 88.8% after the 7-year follow-up. ConclusionsThe clinical behavior of partial fixed dental prostheses with a zirconium dioxide core in the anterior region provides an adequate medium-term survival rate. The main cause of failure was secondary caries. The most frequent complication was chipping, which was directly related to the number of units of the prosthesis.

Wetting Characteristics of a Nano Y-TZP Dental Ceramic by a Molten Feldspathic Veneer

The purpose of this study was to evaluate the wetting behaviour of a molten feldspathic glass-ceramic which is used as a veneering layer on dental Y-TZP cores. The grain size effect of the zirconia substrate on the wettability of the veneering material was also studied. It is suggested that the presence of a weak bond at the interface could be attributed to the poor wetting of ZrO2 surface by the molten veneer. Result of the sessile drop analysis showed high contact angles of more than 110˚ at the initial states of the test. The contact angles were affected by increasing the grain size. An about 6% increase in mean of the contact angles of micro Y-TZP was determined when compared to the nano-structured bodies. It is suggested that the fine microstructure which was observed in the nano Y-TZP body enhances the physical wetting behaviour due to a probable increase in surface energy which is considered as the driving force of wetting. The enhancement which was observed in wettability of the nano-sized Y-TZP at longer times may also be originated from a chemical wetting assisted by the diffusion of the atoms through the increased defects of surface such as grain boundaries and triple junctions.

Bond strength and Raman analysis of the zirconia-feldspathic porcelain interface

Zirconia has the best mechanical properties of the available ceramic systems. However, the stability of the zirconia-feldspathic porcelain interface may be jeopardized by the presence of the chipping and debonding of the feldspathic porcelain. The purpose of this study is to evaluate the shear bond strength of 3 cold isostatic pressed zirconia materials and a feldspathic veneer by analyzing their interface with micro-Raman spectroscopy. The test groups were experimental zirconia, Zirkonzahn zirconia, and Schuetz zirconia. Blocks of partially sintered zirconia were cut into disks (n=20) and then veneered with a feldspathic porcelain. Half of the specimens from each group (n=10) were incubated in 37°C water for 24 hours, and the other half were thermocycled. All the specimens were then subjected to shear testing. The fractured areas were analyzed with optical stereomicroscopy and classified as adhesive, cohesive, or an adhesive-cohesive failure. Spectral patterns were examined to detect bands related to the zirconia and feldspathic porcelain phases. The shear strength data were submitted to 2-way ANOVA. No significant differences in shear bond strength were observed among the 3 groups, regardless of whether or not the specimens were thermocycled. Adhesive failures were the most prevalent types of failure (70%). Raman spectra were clearly distinguished for all the materials, which showed the presence of tetragonal and monoclinic phases. The controlled production of the experimental zirconia did not influence the results of the bond strength. Raman analysis suggested a process of interdiffusion by the presence of peaks associated with the zirconia and feldspathic ceramics.

Proliferation and adhesion capability of human gingival fibroblasts onto zirconia, lithium disilicate and feldspathic veneering ceramic in vitro

Human gingival fibroblasts (HGFs) were cultured onto CAD/CAM zirconia (Group A), CAD/CAM zirconia after polishing (Group B), CAD/CAM lithium disilicate after polishing (Group C), and feldspathic ceramic (Group D) to evaluate their proliferation and adhesion potential. After 3 h, HGF adhesion was similar in all groups. Later, HGFs closely adhered to surfaces, particularly onto groups B, C and D, acquiring an elongated shape. Proliferation assay showed no differences in cell viability among the groups after 24 h, while significant increase was shown after 72 h in Groups B and C. After 24 h, similar Collagen I levels were found in all groups, while after 72 h Groups B and C revealed a deep reduction in respect to the 24 h level. In vitro, HGF behavior may reflect variability in soft tissue response to different surface materials for prosthetic restorations, and support that polished zirconia is able to achieve a better integration in vivo in respect to the other materials.

In vitro chipping behaviour of all‐ceramic crowns with a zirconia framework and feldspathic veneering: comparison of CAD/CAM‐produced veneer with manually layered veneer

The purpose of this in vitro study was to assess the breaking load of zirconia-based crowns veneered with either CAD/CAM-produced or manually layered feldspathic ceramic. Thirty-two identical zirconia frameworks (Sirona inCoris ZI, mono L F1), 0·6 mm thick with an anatomically shaped occlusal area, were constructed (Sirona inLab 3.80). Sixteen of the crowns were then veneered by the use of CAD/CAM-fabricated feldspathic ceramic (CEREC Bloc, Sirona) and 16 by the use of hand-layered ceramic. The CAD/CAM-manufactured veneer was attached to the frameworks by the use of Panavia 2.0 (Kuraray). Half of the specimens were loaded until failure without artificial ageing; the other half of the specimens underwent thermal cycling and cyclic loading (1·2 million chewing cycles, force magnitude F(max) = 108 N) before the assessment of the ultimate load. To investigate the new technique further, finite element (FE) computations were conducted on the basis of the original geometry. Statistical assessment was made by the use of non-parametric tests. Initial breaking load was significantly higher in the hand-layered group than in the CAD/CAM group (mean: 1165·86 N versus 395·45 N). During chewing simulation, however, 87·5% (7/8) of the crowns in the hand-layered group failed, whereas no crown in the CAD/CAM group failed. The CAD/CAM-produced veneer was significantly less sensitive to ageing than the hand-layered veneer.

Effect of surface conditioning modalities on the repair bond strength of resin composite to the zirconia core / veneering ceramic complex.

This study evaluated the effect of different surface conditioning protocols on the repair strength of resin composite to the zirconia core / veneering ceramic complex, simulating the clinical chipping phenomenon. Forty disk-shaped zirconia core (Lava Zirconia, 3M ESPE) (diameter: 3 mm) specimens were veneered circumferentially with a feldspathic veneering ceramic (VM7, Vita Zahnfabrik) (thickness: 2 mm) using a split metal mold. They were then embedded in autopolymerizing acrylic with the bonding surfaces exposed. Specimens were randomly assigned to one of the following surface conditioning protocols (n = 10 per group): group 1, veneer: 4% hydrofluoric acid (HF) (Porcelain Etch) + core: aluminum trioxide (50-µm Al2O3) + core + veneer: silane (ESPE-Sil); group 2: core: Al2O3 (50 µm) + veneer: HF + core + veneer: silane; group 3: veneer: HF + core: 30 µm aluminum trioxide particles coated with silica (30 µm SiO2) + core + veneer: silane; group 4: core: 30 µm SiO2 + veneer: HF + core + veneer: silane. Core and veneer ceramic were conditioned individually but no attempt was made to avoid cross contamination of conditioning, simulating the clinical intraoral repair situation. Adhesive resin (VisioBond) was applied to both the core and the veneer ceramic, and resin composite (Quadrant Posterior) was bonded onto both substrates using polyethylene molds and photopolymerized. After thermocycling (6000 cycles, 5°C-55°C), the specimens were subjected to shear bond testing using a universal testing machine (1 mm/min). Failure modes were identified using an optical microscope, and scanning electron microscope images were obtained. Bond strength data (MPa) were analyzed statistically using the non-parametric Kruskal-Wallis test followed by the Wilcoxon rank-sum test and the Bonferroni Holm correction (α = 0.05). Group 3 demonstrated significantly higher values (MPa) (8.6 ± 2.7) than those of the other groups (3.2 ± 3.1, 3.2 ± 3, and 3.1 ± 3.5 for groups 1, 2, and 4, respectively) (p < 0.001). All groups showed exclusively adhesive failure between the repair resin and the core zirconia. The incidence of cohesive failure in the ceramic was highest in group 3 (8 out of 10) compared to the other groups (0/10, 2/10, and 2/10, in groups 1, 2, and 4, respectively). SEM images showed that air abrasion on the zirconia core only also impinged on the veneering ceramic where the etching pattern was affected. Etching the veneer ceramic with HF gel and silica coating of the zirconia core followed by silanization of both substrates could be advised for the repair of the zirconia core / veneering ceramic complex.

Factors Affecting on the Bond Strength of Dental Zirconia to Veneering Porcelains

The bond strengths between two kinds of zirconia and three kinds of feldspathic veneering porcelains were measured. The specimens were prepared at four firing temperatures for three holding periods, respective opaque porcelain was painted and vacuum-fired. Then, each dentin porcelain was condensed in an acrylic resin mold and vacuum-fired under the conditions mentioned above. Cross sections of the interface between zirconia and porcelain were observed with a scanning electron microscope. The specimens were fixed to specimen holder on a universal testing machine. Data of the bonding test were statistically analyzed. The results showed that all the four factors statistically affected the bonding strength (p&lt;0.01). The contribution of the firing temperature was highest and that of the porcelain type was lowest (p&lt;0.01).

PORCELAIN LAMINATE VENEER ON A HIGHLY DISCOLORED TOOTH: A CASE REPORT

Porcelain Laminate Veneer is used widely throughout the world for esthetic correction for discolored and damaged tooth structures. Esthetic treatment of a single darkened tooth represents a great challenge to the dental practitioner. The properties of dental ceramic - colour stability, mechanical strength, clinical longevity, esthetic appearance and compatibility with periodontal tissues make this material a good choice for such treatment. A case of restoration of a single highly darkened anterior tooth with a feldspathic porcelain veneer. Resolution involved preparation of the dental structure. Conservative use of porcelain laminate veneers provides satisfactory esthetic outcomes and preserves sound tooth structure. The patient was very satisfied with the result and had no complaints in the follow-ups.