Three-dimensional Quantification of Enamel Preservation in Tooth Preparation for Porcelain Laminate Veneers: A Fully Digital Workflow In Vitro Study

SUMMARY Objective: This in vitro study aimed to evaluate the preservation of enamel after tooth preparation for porcelain laminate veneers (PLVs) at different preparation depths based on a fully digital workflow. Methods and Materials: Sixty extracted human maxillary anterior teeth, including 20 maxillary central incisors (MCIs), 20 maxillary lateral incisors (MLIs), and 20 maxillary canines (MCs) underwent microcomputed tomography (CT) scanning, and were reconstructed as three-dimensional (3D) enamel and dentin models. Subsequently, the three-dimensional (3D) enamel models were imported into Materialise, where each enamel model underwent seven types of virtual preparation for PLVs at preparation depths at 0.1-mm increments from 0.1-0.3-0.5 mm (D1) to 0.7-0.9-1.1 mm (D7). The enamel surface was depicted by merging the virtual preparation and, respective, dentin models. The enamel area and prepared surface were measured to calculate the percentage of enamel (R%). The data were statistically analyzed using one-way analysis of variance (ANOVA) (α=0.05). Results: The group-wise mean (standard deviation) R values for the MCIs were as follows: D1-D3: 100.00 (0) each, and D4-D7: 74.70 (2.45), 51.40 (5.12), 24.40 (3.06), and 0.00 (0), respectively. The group-wise mean R values for the MLIs were 100.00 (0), 73.70 (3.40), 53.50 (3.44), 25.20 (3.79), and 0.90 (0.99) for the D1-D5 groups, respectively; and 0.00 (0) each for the D6-D7 groups. The group-wise mean (standard deviations) R values for the MCs were as follows: D1-D3: 100.00 (0) each, and D4-D7: 99.00 (1.34), 77.10 (3.28), 74.20 (3.61), and 52.20 (4.09), respectively. The one-way ANOVA revealed significant differences between the seven groups in the MCIs, MLIs, and MCs (p<0.05). Conclusions: Our results recommended preparation depths of up to 0.3-0.5-0.7 mm (MCIs), 0.1-0.3-0.5 mm (MLIs), and 0.4-0.6-0.8 mm (MCs) to facilitate complete intraenamel preparation. Moreover, 50% enamel was preserved at preparation depths of 0.5-0.7-0.9 mm (MCIs), 0.3-0.5-0.7 mm (MLIs), and 0.7-0.9-1.1 mm (MCs).

Shear bond strength of ceramic laminate veneers to finishing surfaces with different percentages of preserved enamel under a digital guided method

Background The purpose of this in vitro study was to evaluate the effect of the percentages of preserved enamel on ceramic laminate veneers’ (CLVs) shear bond strength (SBS). Methods Seventy extracted human maxillary central incisors were scanned and reconstructed into three-dimensional models. The extracted teeth were then embedded and randomly divided into seven groups (n = 10 per group). Based on digital analyses of the three-dimensional models, guided tooth preparation and bonding procedures were performed individually to form seven different percentages (100%, 80%, 60% 50%, 40%, 20% and 0%) of remaining enamel thickness on the bonding surface. Finally, the SBS test was performed, and the data were statistically analysed by one-way ANOVA with LSD post hoc test (α = 0.05). Results The complete enamel surface exhibited the highest SBS (19.93 ± 4.55 MPa), followed by 80% enamel (19.03 ± 3.66 MPa), 60% enamel (18.44 ± 3.65 MPa), 50% enamel (18.18 ± 3.41 MPa), 40% enamel (17.83 ± 3.01 MPa) and 20% enamel (11.32 ± 3.42 MPa) group. The lowest SBS (9.63 ± 3.46 MPa) was detected in 0% enamel group. No significant difference was observed among the 40–100% enamel groups, while the 20% or 0% enamel group demonstrated a significantly lower mean SBS than the 40% enamel group (p < 0.05). Conclusion The SBS value of CLVs bonded to 100% enamel on the finishing surfaces (nearly 20 MPa) was twice that which bonded to 0% enamel (nearly 10 MPa). Bonding to 100% enamel is the most reliable treatment. When dentin exposure is inevitable, enamel should be preserved as much as possible to maintain good bonding. In addition, 40% of preserved enamel on the bonding surface was the minimal acceptable value to fulfil the requirements of good bonding strength.

Survival of Hybrid Laminate Veneers using two different tooth preparation techniques: Randomized Clinical Trial

The aim of this study was to evaluate the survival of laminate veneers constructed using a recent polymer-infiltrated ceramic network material following the aesthetic pre-evaluative temporary (APT) technique of tooth preparation in comparison to traditional technique. Six patients received 54 laminate veneers. They were divided into two equal groups (n=27) according to the technique of tooth preparation: group T: traditional technique and group A: aesthetic pre-evaluative temporary technique. VITA ENAMIC material was used for CAD/CAM construction of laminate veneers. Cementation was performed using a light cured resin cement. The laminate veneers were evaluated at baseline, after 3, 6 and 12 months according to the modified United States Public Health Service (USPHS) criteriea. The data was collected, tabulated and statistically analyzed. Secondary caries, endodontic complications, cracks and loss of retention were not noted in any laminate veneer. Extensive fractures were not detected in both study groups through the study period. There was a statistically significant decrease of color match criteria between the two groups at the 6 and 12 months recalls. Based on this study, both preparation techniques resulted in successful clinical performance. After 12 months, all the veneers in both groups showed no post-operative sensitivity and all patients were highly satisfied regarding their veneers. However, there was a deterioration in color match criteria through the study period in both study groups.

Influence of Resin Cements and Ceramic types on the Color Stability and Translucence of Laminate Veneers/ Influência dos Cimentos de Resina e Tipos Cerâmicos na Estabilidade da Cor e Translucidez das Facetas Laminadas

Objective: This study evaluated the color stability and translucence of resin cements in the fixation of ceramic veneers submitted to aging protocols. Material and Methods: Buccal faces of bovine incisors were planed up to dentin. Eighty ceramic veneers (1 mm) were prepared using two pressed ceramics (IPS e-maxPress and IPS e-maxZirpress, IvoclarVivadent). Before the initial color and translucence readouts (Vita EasyShade, VITA), the veneers were fixed with light (Variolink II, Ivoclar/Vivadent) or dual cured (Relyx U200, 3M ESPE) cements. The samples were submitted (n=10) to thermal mechanical cycling (1.200.000 cycles, 1,3Hz, 5°C/37°C/55°C); and no aging protocol (control). New color and translucence readouts were performed. The cement thickness was quantified by a double coordinate stereomicroscope (Nikon Measurescope) as a control of the study. Results: Data (3-way ANOVA, Tukey, p0,05) showed difference (p0.05) in the color change for both ceramics cemented with U200 with no aging protocol. In the other groups, there was no significant difference (p0.05). There was no difference for translucence regardless ceramics, cements, or aging protocol. Thermal mechanical cycling was not significant for optical changes of the ceramics tested. Conclusions: It was concluded that the color stability and translucence of ceramics with thickness of 1mm were not influenced by the cement when submitted to thermal mechanical cycling.

Conceitos atuais sobre a performance clínica e principais falhas do tratamento restaurador com laminados cerâmicos: uma revisão da literatura

O objetivo do presente estudo foi revisar a literatura dos últimos cinco anos e identificar os índices de sobrevivência, principais causas de falha relatadas e verificar a confiabilidade dos laminados cerâmicos como tratamento estético e funcional em longo prazo. Métodos: foi realizada uma busca ativa na Biblioteca Nacional de Medicina dos Estados Unidos (pubmed.ncbi.nlm.nih.gov), através da base de dados Medline, dos últimos cinco anos (2015-2020) na língua inglesa, utilizando os descritores: Laminate Veneers, Porcelain Laminate Veneers e Ceramic Laminate Veneers, que resultou em 35 artigos. Após a leitura dos resumos, foram excluídos 9 estudos que utilizaram laminados cerâmicos não produzidos em cerâmicas feldspáticas, ou vidro ceramizados reforçados por cristais de leucita, ou dissilicato de lítio. Foram selecionados 26 artigos categorizados como: relatos de caso, estudos clínicos, estudos in vitro e revisões de literatura. Resultados: os estudos apontaram índices de sobrevivência de 100%, após 2 anos de cimentação, até valores superiores a 80%, após 14 anos. As três principais causas de falhas apontadas foram: desadaptação de marginal (37%), pigmentação das margens (30%) e fratura ou lascamento das restaurações (3%). Considerações finais: dentro das limitações do estudo, foi possível concluir que as principais causas de falha estão associadas às margens da restauração, no entanto, os laminados cerâmicos podem atingir índices elevados de sobrevivência mesmo 14 anos após a cimentação, mostrando um alto nível de confiabilidade.

Social Media Research on "Laminate Veneer": During Covid 19-Pandemic

Objective: The difficulty of asking questions to each other during the appointment process with their doctor, the long waiting times of the patients in the waiting rooms in the clinics, and the fact that it is easier to get medical information on the internet due to the ongoing COVID-19 virus infection. Porcelain laminate veneers (PLVs) have been frequently used to restore anterior teeth for nearly three decades, thanks to their aesthetic appeal, durability and biocompatibility.Methods: YouTube™ was searched by a researcher of this study using the keyword 'laminate veneer' on April 17, 2021. The most frequently used terms in this regard are 'laminate veneer' and 'laminate veneer restoration'. Analyzes were made on the Instagram application, along with YouTube.Results: Thirty-three videos were determined on YouTube™ on the topic of laminate veneer. The mean number of the views was 46277.84 ± 128674.71, with the minimum view as ten and maximum as 682478. The videos had a mean duration of 5:48 ± 4:64 with a range of 0:24–14:55. The mean number of "likes" for each video was 198 ± 424, and the mean number of "dislikes" was 17 ± 48. The most-liked video received 1700 "likes." The most-disliked video received 236"dislikes." The mean number of comments was 13.65 ± 31.58. The interaction rate was 1.67 ± 5.18, and the viewing rate was 2939.11 ± 6076.75Conclusion: YouTube™ and Instagram still cannot be accepted as a completely confident resource of knowledge for patients who want to learn about oral aesthetic rehabilitation treatment with laminate veneers

CERAMIC LAMINATE VENEERS: A 3-YEAR CLINICAL FOLLOW-UP

Ceramic laminate veneers have been widely used in esthetic restorations, with advantages such as color stability, resistance to degradation, and excellent esthetic results, all of which contribute to long-term stability. The gold standard technique consists of bonding a thin ceramic laminate veneer to enamel. The present paper describes a clinical case with 3-year follow-up. Six ceramic laminate veneers were planned, fabricated and bonded to six sound anterior maxillary teeth showing diastema, thereby improving shape and size. The procedure followed a laminate veneer treatment protocol, using a mock-up, shade selection, and an adhesive system. The case was followed for 3 years. In conclusion, minimally invasive restorations with ceramic laminate veneers remained stable after 3 years of follow-up and are a good option for patients with diastema or microdontia and requires only a minimum amount of sound tooth tissue removal.