Dental Veneers Research Articles

Role of CaF2 on mechanochemically synthesized leucite as dental veneering glass ceramics

Leucite based glass ceramic is widely used in dental ceramics as porcelain fused to metals for veneering applications. Main properties considered here are high coefficient of thermal expansion and good mechanical properties. Owing to these requirements, high expansion phase such as leucite is incorporated in these glass ceramics. The present work was aimed to synthesise leucite using its stoichiometric batch compositions and subsequent high energy ball milling. CaF2 was also added in another mix to study its role on leucite formation. Further prepared, leucite phase was added in separately prepared low temperature glass frit powders to control amount of glass and leucite content. X-ray diffraction results displayed that high energy ball milling and additive promoted the formation of leucite as a major crystalline phase. Furthermore, CaF2 also suppressed the subsidiary crystallisation of kalsilite phase. Evaluated average coefficient of thermal expansion in the temperature range of 20–500°C was very close to the theoretical value of pure leucite.

A Systematic Review and Meta - Analysis of the Survival of Non - Feldspathic Porcelain Veneers over 5 and 10 Years

Purpose: This systematic review aimed to report and explore the survival of dental veneers constructed from non-feldspathic porcelain over 5 and 10 years. Materials and Methods: A total of 4,294 articles were identified through a systematic search involving all databases in the Cochrane Library, MEDLINE (OVID), EMBASE, Web of Knowledge, specific journals (hand-search), conference proceedings, clinical trials registers, and collegiate contacts. Articles, abstracts, and gray literature were sought by two independent researchers. There were no language limitations. One hundred sixteen studies were identified for full-text assessment, with 10 included in the analysis (5 qualitative, 5 quantitative). Study characteristics and survival (Kaplan-Meier estimated cumulative survival and 95% confidence interval [CI]) were extracted or recalculated. A failed veneer was one which required an intervention that disrupted the original marginal integrity, had been partially or completely lost, or had lost retention more than twice. A meta-analysis and sensitivity analysis of Empress veneers was completed, with an assessment of statistical heterogeneity and publication bias. Clinical heterogeneity was explored for results of all veneering materials from included studies. Results: Within the 10 studies, veneers were fabricated with IPS Empress, IPS Empress 2, Cerinate, and Cerec computer-aided design/computer-assisted manufacture (CAD/ CAM) materials VITA Mark I, VITA Mark II, Ivoclar ProCad. The meta-analysis showed the pooled estimate for Empress veneers to be 92.4% (95% CI: 89.8% to 95.0%) for 5-year survival and 66% to 94% (95% CI: 55% to 99%) for 10 years. Data regarding other non-feldspathic porcelain materials were lacking, with only a single study each reporting outcomes for Empress 2, Cerinate, and various Cerec porcelains over 5 years. The sensitivity analysis showed data from one study had an influencing and stabilizing effect on the 5-year pooled estimate. Conclusion: The long-term outcome (> 5 years) of non-feldspathic porcelain veneers is sparsely reported in the literature. This systematic review indicates that the 5-year cumulative estimated survival for etchable non-feldspathic porcelain veneers is over 90%. Outcomes may prove clinically acceptable with time, but evidence remains lacking and the use of these materials for veneers remains experimental. Int J Prosthodont 2013; 26: 111-124. doi: 10.11607/ijp.3202

Fracture and shear bond strength analyses of different dental veneering ceramics to zirconia

The purpose of this work was to evaluate the interaction of different layering porcelains with zirconia via shear bond strength test and microscopy. Four different groups of dental veneering porcelains (VM9, Zirkonzanh, Ceramco, IPS) were fused onto forty zirconia-based cylindrical substrates (8mm in diameter and 12mm in height) (n=10), according to the manufacturer's recommendations. Additionally, layered dental porcelain (D-sign, Ivoclar) was fired on ten Ni–Cr cylindrical substrates Shear bond strength tests of the veneering porcelain to zirconia or Ni–Cr were carried out at a crosshead speed of 0.5mm/min. After the shear bond tests, the interfaces were analyzed by scanning electron microscopy (SEM). The fracture type exhibited by the different systems was also assessed. The results were statistically analyzed by ANOVA at a significant level of p<.05. The shear bond strength values of the porcelain-to-NiCr interfaces (25.3±7.1MPa) were significantly higher than those recorded for the following porcelain-to-zirconia systems: Zirkonzanh (18.8±1MPa), Ceramco (18.2±4.7MPa), and IPS (16±4.5MPa). However, no significant differences were found in the shear bond strength values between the porcelain-to-NiCr and porcelain (VM9)-to-zirconia (23.2±5.1MPa) groups (p>.05). All-ceramic interfaces revealed mixed failure type, cohesive in the porcelain and adhesive at the interface.This study demonstrated that all-ceramic systems do not attain yet the same bond strength standards equivalent to metal–ceramic systems. Therefore, despite the esthetic appeal of all-ceramic restorations, the adhesion between the porcelain and zirconia framework is still an issue considering the long term success of the restoration.

Microhardness and Biocompatibility of Silicon Nitride Ceramic Developed for Dental Applications

Silicon nitride (Si3N4) ceramic is an attractive material for dental applications, especially used as a dental core material, due to its unique properties including high fracture toughness, high strength, high wear resistance and non-cytotoxicity. In this study, the Si3N4 ceramic was fabricated by a non-pressure sintering technique at a relatively low sintering temperature of 1650℃ in nitrogen atmosphere. Borosilicate glass and 5 wt% ZrO2-added borosilicate glass were used for coating on the Si3N4 core surface because of their compatibility in thermal expansion, high chemical resistance and bio-inert. The specimens were then fired in electric tube furnace at 1100℃. The Vickers microhardness of borosilicate glass and 5 wt% ZrO2-added borosilicate glass veneering materials were measured and compared with the commercial dental veneer porcelain as a control (VITA VMK 95). The cytotoxicity of the Si3N4 ceramic and the veneering materials were tested by MTT assay, using human gingival fibroblasts (HGF) and periodontal ligament fibroblasts (HPDLF). The results indicate that the Si3N4 ceramic and Si3N4 ceramic veneered with borosilicate glass or 5 wt% ZrO2-added borosilicate glass veneering materials tested in this study are not toxic to oral tissue and can be used to produce dental prostheses.

Reabilitação Estética Anterior pela Técnica do Facetamento - Relato de Caso

Objective: This study aimed to present a clinical case report in which aesthetic direct composite resin veneer technique was employed as a restorative alternative to treat anterior teeth. Case report: Aesthetic veneers were made on the maxillary anterior teeth of a patient, female, 38 years old, who attended the Integrated Dental Clinics at Federal University of Paraiba complaining of aesthetic dissatisfaction with her old fillings. The treatment was initiated by endodontic and periodontal procedures in order to provide the patient with hygiene conditions. After tooth color selection, isolation of operative field was performed and teeth were prepared using diamond burs #1014 and #2135 (KG Sorensen, Sao Paulo, Brazil). Subsequent steps consisted of dental acid etching, adhesive system application, and composite resin insertion, sculpture, finishing and polishing. Conclusion: It is concluded that the use of composite resins to aesthetically rehabilitate anterior teeth has represented a conservative and feasible alternative for dental treatment, and it reestablishes the patient’s biological and psychological health. DESCRIPTORS Esthetics, Dental. Composite Resins. Dental Veneers.

Nonparametric estimation in an “illness‐death” model when all transition times are interval censored

We develop nonparametric maximum likelihood estimation for the parameters of an irreversible Markov chain on states {0,1,2} from the observations with interval censored times of 0 → 1, 0 → 2 and 1 → 2 transitions. The distinguishing aspect of the data is that, in addition to all transition times being interval censored, the times of two events (0 → 1 and 1 → 2 transitions) can be censored into the same interval. This development was motivated by a common data structure in oral health research, here specifically illustrated by the data from a prospective cohort study on the longevity of dental veneers. Using the self-consistency algorithm we obtain the maximum likelihood estimators of the cumulative incidences of the times to events 1 and 2 and of the intensity of the 1 → 2 transition. This work generalizes previous results on the estimation in an "illness-death" model from interval censored observations.

A Systematic Review and Meta-Analysis of the Survival of Non-Feldspathic Porcelain Veneers Over 5 and 10 Years

This systematic review aimed to report and explore the survival of dental veneers constructed from non-feldspathic porcelain over 5 and 10 years. A total of 4,294 articles were identified through a systematic search involving all databases in the Cochrane Library, MEDLINE (OVID), EMBASE, Web of Knowledge, specific journals (hand-search), conference proceedings, clinical trials registers, and collegiate contacts. Articles, abstracts, and gray literature were sought by two independent researchers. There were no language limitations. One hundred sixteen studies were identified for full-text assessment, with 10 included in the analysis (5 qualitative, 5 quantitative). Study characteristics and survival (Kaplan-Meier estimated cumulative survival and 95% confidence interval [CI]) were extracted or recalculated. A failed veneer was one which required an intervention that disrupted the original marginal integrity, had been partially or completely lost, or had lost retention more than twice. A meta-analysis and sensitivity analysis of Empress veneers was completed, with an assessment of statistical heterogeneity and publication bias. Clinical heterogeneity was explored for results of all veneering materials from included studies. Within the 10 studies, veneers were fabricated with IPS Empress, IPS Empress 2, Cerinate, and Cerec computer-aided design/computer-assisted manufacture (CAD/CAM) materials VITA Mark I, VITA Mark II, Ivoclar ProCad. The meta-analysis showed the pooled estimate for Empress veneers to be 92.4% (95% CI: 89.8% to 95.0%) for 5-year survival and 66% to 94% (95% CI: 55% to 99%) for 10 years. Data regarding other non-feldspathic porcelain materials were lacking, with only a single study each reporting outcomes for Empress 2, Cerinate, and various Cerec porcelains over 5 years. The sensitivity analysis showed data from one study had an influencing and stabilizing effect on the 5-year pooled estimate. The long-term outcome (> 5 years) of non-feldspathic porcelain veneers is sparsely reported in the literature. This systematic review indicates that the 5-year cumulative estimated survival for etchable non-feldspathic porcelain veneers is over 90%. Outcomes may prove clinically acceptable with time, but evidence remains lacking and the use of these materials for veneers remains experimental.

The effect of chlorhexidine on the colour and tint change of ceramic dental veneer

Frequent consumption of certain products contained the different kinds of chemical compounds affects on the colour of teeth, especially on prosthetic restoration timbre. A very interesting issue is to determine the effect of exposure in some of the commonly used chemical substances on dental restorations colour change. The study was conducted on the upper crown of the tooth, namely the first incisor. The colour evaluation change has been made using a spectrophotometer SpectroShade, which determines the amount of light absorbed by the element over the entire visible spectrum 380 - 720 nm. In the paper was shown that long-term use of products that contain chlorhexidine can lead to permanent color change of ceramics dental materials. After long exposure in the solution the ceramic became lighter but their hue value indicates that the color is closer to yellow.

Nonparametric estimation of the cumulative intensities in an interval censored competing risks model

The nonparametric maximum likelihood estimation (NPMLE) of the distribution function from the interval censored (IC) data has been extensively studied in the extant literature. The NPMLE was also developed for the subdistribution functions in an IC competing risks model and in an illness-death model under various interval-censoring scenarios. But the important problem of estimation of the cumulative intensities (CIs) in the interval-censored models has not been considered previously. We develop the NPMLE of the CI in a simple alive/dead model and of the CIs in a competing risks model. Assuming that data are generated by a discrete and finite mixed case interval censoring mechanism we provide a discussion and the simulation study of the asymptotic properties of the NPMLEs of the CIs. In particular we show that they are asymptotically unbiased; in contrast the ad hoc estimators presented in extant literature are substantially biased. We illustrate our methods with the data from a prospective cohort study on the longevity of dental veneers.

Nano grain sized zirconia–silica glass ceramics for dental applications

Abstract Glass ceramics based on lithium disilicates are commonly used in dental veneers and crowns. Alternative materials with improved mechanical properties may be of interest for more demanding applications, e.g. bridgeworks. In this study, a sol–gel method was optimized to produce nano grain-sized zirconia–silica glass ceramics with properties adequate for dental applications. The material properties were compared to those of IPS e.max ® CAD, a commercially available lithium disilicate. The zirconia–silica glass ceramic was found to be translucent, with a transmittance of over 70%, and possessed excellent corrosion resistance. It also presented a somewhat lower elastic modulus but higher hardness than the lithium disilicate, and with the proper heat treatment a higher fracture toughness was achieved for the zirconia–silica glass ceramic. In conclusion, the material produced in this study showed promising results for use in dental applications, but the production method is sensitive and large specimen sizes may be difficult to achieve.

Matching Ability of Dental Shaded Zirconia Ceramics and Veneering Porcelain

The matching properties of ceramics and veneering porcelain play an important role for the overall color and mechanical properties of dental crowns. The Vita VM9 veneering porcelain was coated on the surfaces of two zirconia, three-point flexural strength, heat shock resistance and the overall color after veneered with porcelain were tested. The results showed that the interlayer cracks, radial cracks or porcelain body cracks were not appeared in all samples during thermal shock experiments at 60~220°C. Their flexural strength was all above 700MPa and the overall color covered the common color of VITA-3D Master shade guide. There is good thermal compatibility between the two dental shaded zirconia ceramics and Vita VM9 veneering porcelain. The mechanical properties are suitable for clinical posterior teeth area restorative, and the overall color is also suitable for the requirements on the color and brightness of clinical dental restoration.

Advances in dental veneers: materials, applications, and techniques

Advances in dental veneers: materials, applications, and techniques

Advances in dental veneers: materials, applications, and techniques

Laminate veneers are a conservative treatment of unaesthetic anterior teeth. The continued development of dental ceramics offers clinicians many options for creating highly aesthetic and functional porcelain veneers. This 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 current literature was reviewed to search for the most important parameters determining the long-term success, correct application, and clinical limitations of porcelain veneers.

Dental veneers overused, says dental expert

Dental veneers overused, says dental expert

Comparison of color and translucency between resin and try-in paste with same number

To test and compare the color and translucency between the mono-component light-cure adhesive resin and try-in paste with same number for porcelain veneer restorations, and evaluate the consistency of the materials. Variolink Veneer and Relyx Veneer were involved in the study. The adhesive resins and try-in pastes were added into a model of diameter of 10 mm and thick of 2 mm with white background and covered with filtered cover glass, and then the resins was cured with light. The color (L(*), a(*), b(*)) of these samples was test and ΔE was also calculated to evaluate the color consistency of samples. The resins and try-in pastes were made into a thin layer of 0.15 mm, and their translucency was tested under the light from 380 µm to 780 µm. Average translucency was calculated. Tukey t-test for multiple comparisons was used to analysis the differences of ΔE. Paired t-test was used to analysis the differences of translucency of them. Tukey's t-test shows that the evaluation of ΔE of TR (1.11 ± 0.18) was a; those of LV-1 (6.38 ± 0.45), LV-2 (5.94 ± 0.19), A1 (7.54 ± 0.20), WO (4.24 ± 1.14) were b; those of HV + 2 (10.90 ± 0.41), HV + 1 (11.48 ± 0.17), LV-3 (10.69 ± 0.13), B0.5 (13.26 ± 0.21) were c; and those of HV + 3 (21.94 ± 0.21), MV0 (29.78 ± 0.14), A3 (32.67 ± 0.19) were d (a, b, c, d meaned that the consistency of resin and try-in paste became lower and lower). There were significant differences between resin and tray-in paste in 7 colors (A1, TR, HV + 3, HV + 2, HV + 1, LV-2, LV-3) of 12 colors (P < 0.01). The consistency of color and translucency between most adhesive resin and try-in paste with same number is low. This kind of materials should be used with caution in demanding cases.

Improperly Formed Maxillary Teeth

A general dentist referred a 14-year-old boy to an oral surgeon (J.S.S.) because he was missing multiple maxillary left teeth. The patient was otherwise asymptomatic, and the principal concern was the missing teeth. The patient was healthy and had undergone surgery to correct hypospadias (congenital malformation of the penis in which the urethral opening is on the underside) at 3 years of age. The results of an extraoral examination revealed normal facial symmetry. The results of an intraoral clinical examination showed hypoplasia of the left posterior maxillary alveolar process but normal occlusion. The left maxillary premolars were absent (Figure 1). The patient had retained his left maxillary primary canine, which had been extracted two weeks before the oral surgeon examined him. The maxillary lateral incisors had been peg shaped and had received dental veneers. Eruption of tooth no. 27 was delayed. No masses were palpable, and the overlying mucosa and gingiva appeared normal. The involved teeth had no history of caries or trauma. The patient’s oral hygiene was excellent. We obtained a computed tomographic scan of the patient. It revealed segmental deformity or dysplasia of the left maxillary alveolar ridge with associated deformity in the position or development of the maxillary left canine and first and second premolars. We detected no other skeletal abnormalities. We also noted these defective maxillary teeth on the panoramic and periapical radiographs (Figures 2 and 3). The maxillary left first and second molars appear to be normal in position and appearance, and the mandibular teeth were normal in appearance. The oral surgeon surgically removed the defective teeth and submitted them to oral pathologists (I.B., D.M.C.) for microscopic examination. Histopathological examination of the decalcified hard tissue revealed anomalous toothlike structures associated with spherical droplets of cementumlike material. We noted aggregates of calcified abnormal dental hard tissue in the defective teeth (Figure 4).

A retrospective study on the long-term clinical outcomes of 310 porcelain laminate veneers

To investigate the long-term clinical outcomes of porcelain laminate veneers 1-8 years following delivery. A total of 310 feldspathic porcelain laminate veneers on anterior teeth or premolars in 49 patients were included in the present study 1-8 years following delivery. All the subjects underwent a detailed clinical examination utilizing modified United States Public Health Service (USPHS) criteria. Restoration integrity, abrasion, color satisfaction, marginal discoloration, marginal adaptation, secondary caries, postoperative sensitivity, and gingival index (GI) of the prostheses were evaluated according to modified USPHS criteria. The 1-8 year survival rates of the veneers were statistically analyzed using the life table method. The survival rates of porcelain laminate veneers were 98.7%, 98.0%, 93.8%, 93.2%, 89.7%, 81.8%, 76.3%, and 76.3% in 1 to 8 years, respectively. The long-term clinical outcomes of porcelain laminate veneers are satisfying.

A non-destructive method to determine critical flaw size of dental veneering ceramics

A non-destructive method to determine critical flaw size of dental veneering ceramics

Effect of Multiple Firing on Wear Behavior of Dental Veneering Ceramic

This study investigated the effect of multiple firing on the wear behavior of dental all-ceramic veneering ceramic (Cercon). Samples were fabricated according to the manufacturer's requirement for different firing times. The wear test was operated under simulated oral environment. The results showed that multiple firing could influence wear behavior of all-ceramic Veneer. Significant difference was observed in wear scar width among different samples. All the groups except 7time-firing one showed good wear resistance with low wear rate, smooth surface and relatively constant frictional coefficient. With the increasing firing times the wear scar width became larger. The wear resistance of dental ceramic after seven times firing was significantly lower. SEM/DFM results showed the wear facets of veneering ceramic demonstrate grooves characteristic of abrasive wear. The significant change was that severe wear dominated by brittle fracture could be seen in the 7time-firing group. Multiple firing can decrease the wear resistance of dental all-ceramic Veneer, and the wear pattern has the tendency to severe wear. The possible explanation is that the microstructure and properties of all-ceramic Veneering changed during multiple firing.

Fracture toughness determination of two dental porcelains with the indentation strength in bending method

Objective This study was to investigate the influence of the bending test configurations and the crosshead displacement speeds on the fracture toughness ( K Ic) of dental porcelains obtained with the indentation strength in bending (ISB) method. Methods The strength of the dental veneering porcelains Duceram and Sintagon Zx, Vickers’ indented at a load of 2 kg was measured at a crosshead speed of 0.5 mm/min with three test configurations, which were 3-point, 4-point, and biaxial bending. Two more groups of Sintagon Zx were tested the same way, but at speeds of 0.1, and 0.05 mm/min, respectively. Both porcelains, the three crosshead speeds, and the three test configurations were compared statistically. Results Duceram had a higher toughness than Sintagon Zx with all three test configurations and there was no significant difference between three test configurations with either porcelain. Within the crosshead speed groups of Sintagon Zx, a significant difference was found only in the 0.5 mm/min group between the 3-point, and 4-point configurations. Within the configuration groups, significant differences were found between all speeds with the 3-point configuration and only between the highest and lowest speed with the 4-point and the biaxial tests. Conclusion The crosshead displacement speed can cause statistically different results of fracture toughness obtained with the ISB method.