Clinical longevity of ceramic laminate veneers bonded to teeth with and without existing composite restorations up to 40 months

Clinical performance of laminate veneers: A review of the literature

PURPOSE

This narrative review aimed to survey the clinical outcomes of laminate veneers (LVs), including their survival and success rates.

STUDY SELECTION

An electronic search of MEDLINE/PubMed, Web of Science, Cochrane Library, and Google Scholar from 2000 to April 2023 was conducted using the keywords "laminate" OR "veneer" OR "porcelain" OR "feldspathic" OR "lithium disilicate" OR "composite resin" OR "zirconia" OR "survival" OR "success." Case reports, case series, reviews, abstracts, in vitro studies, and observational studies were excluded. Five researchers independently evaluated the titles and abstracts of all identified studies.

RESULTS

A total of 55 studies were identified. None of the studies met the criteria for zirconia LVs. According to the studies in this review, LVs fabricated with feldspathic porcelain, leucite-reinforced glass ceramics (LRG), and lithium disilicate ceramics (LDS) exhibited satisfactory survival and success rates. Furthermore, hydrofluoric acid etching followed by silane priming of the surface of ceramic LVs is necessary for improved clinical outcomes. The extent of dentin exposure significantly decreases the success rate of ceramic LVs. An appropriate adhesive luting process is required to achieve the long-term success of ceramic LVs. Dentin exposure should be minimized or sealed during tooth preparation to achieve a reliable and durable bond between LVs and abutment teeth.

CONCLUSIONS

Based on this narrative review of the literature, the use of silica-based ceramic feldspathic porcelain, LRG, and LDS is recommended for LVs.

Clinical longevity and trend analysis of 801 ultrathin ceramic veneers: A clinical cohort study

STATEMENT OF PROBLEM

Whether ultrathin ceramic veneers are a suitable treatment alternative to conventional ceramic veneers is unclear.

PURPOSE

The purpose of this prospective clinical cohort study was to evaluate the efficacy and longevity of nonpreparation and minimally invasive ceramic veneers and the influence of existing restorations and ceramic type and to define the relationship between the number of veneers placed on different teeth and in different locations, as well as age and sex correlations.

MATERIAL AND METHODS

A total of 801 veneers were placed on incisors, canines, and premolars on maxillary and mandibular teeth between January 2011 and August 2019 (ABR number: RNN/92/19/KE). Feldspathic or feldspathic and lithium disilicate veneers were made, etched, silanated, and cemented. The restorations were evaluated 2 weeks after placement and then every 6 months by using the modified United States Public Health Service (USPHS) criteria. The relationship between participant age and number of veneers was analyzed by using the Spearman rank coefficient test and the Mann-Whitney U test. Changes in the number of participants and veneers in subsequent years were analyzed based on the Spearman rank correlation coefficient. The trend between the location of veneers and the sex of the participants was analyzed by using the chi-squared test for trend. Longevity tables and a survival curve for the veneers were prepared based on the Kaplan-Meier method. The relationships between veneer longevity and the type of ceramic used and the presence of restorations were compared by using the Taron-Ware test (α=.05).

RESULTS

The mean longevity of the intact veneers was 8.45 years. Clinical success was 99.7% after 1 year and 97.9% after 4 years; this value remained constant until the end of the study. Most participants were women (n=122; 84.1%), and the mean age was 41 years; median 40 years. The number of veneers placed on mandibular teeth each year increased over the subsequent years.

CONCLUSIONS

The longevity of ultrathin veneers after 9 years of observation was not related to the ceramic used or to the presence of a composite resin restoration. Veneers were more commonly placed in middle-aged women and in mandibular anterior teeth.

Clinical survival and complication rate of ceramic veneers bonded to different substrates: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Evidence on the long-term clinical assessment and longevity of ceramic veneers bonded to different substrates is limited.

PURPOSE

The purpose of this systematic review and meta-analysis was to evaluate the effect of various substrates, including enamel, dentin, or an existing composite resin restoration, on the clinical survival and complication rates of ceramic veneers.

MATERIAL AND METHODS

The PubMed, Scopus, and the Cochrane Library electronic databases were searched, and related journals were hand searched without time or language restrictions to identify clinical trials that compared the survival rate and clinical complication rates when bonding ceramic veneers to different tooth substrates. The success rate of the included participants was estimated by the number of veneers that did not require a clinical intervention, and the survival rate by all veneers that did not fail absolutely. The risk difference (RD) with 95% confidence intervals (CIs) for dichotomous outcomes was used to quantify the intervention effect.

RESULTS

Of 973 screened articles, 6 clinical studies were included. The survival and success rates varied depending on the bonding substrate. Enamel-bonded veneers had almost perfect rates of survival (99% with a range of 98% to 100%) and success (99% with a range of 98% to 100%). Veneers bonded to composite resin or surfaces with minimal dentin exposure had slightly lower survival rates (94% with a range of 91% to 97% and 95% with a range of 91% to 100%, respectively) and success rates (70% with a range of 60% to 80% and 95% with a range of 90% to 99%). Severe dentin exposure significantly decreased both survival rates (91% with a range of 84% to 98%) and success rates (74% with a range of 64% to 85%). The combined findings suggested that ceramic veneers bonded to enamel had fewer clinical complications (RD: -0.04; 95% CI: -0.09 to 0.02) and lower failure rates (RD: -0.13; 95% CI: -0.32 to 0.07) compared with those bonded to exposed dentin. Additionally, veneers attached to teeth with minimal dentin exposure were significantly less likely to require clinical interventions (RD: -0.16; 95% CI: -0.31 to -0.01) and had a reduced incidence of failure (RD: -0.08; 95% CI: -0.17 to 0.01) compared with those with severe dentin exposure.

CONCLUSIONS

Ceramic veneers bonded to enamel showed higher survival and success rates with lower clinical incidences of complications and failure than those bonded to dentin or teeth with existing composite resin restorations.

Clinical benefits of immediate dentin sealing: A systematic review and meta-analysis

STATEMENT OF PROBLEM

The clinical complications, success, and survival rates of indirect restorations delivered with the immediate dentin sealing protocol are unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to find and collect evidence on the clinical complication, success, and survival rates of indirect restorations delivered with immediate dentin sealing.

MATERIAL AND METHODS

Electronic databases were searched for clinical studies on immediate dentin sealing up to December 2023, without language or time limitations. The records were included if they were clinical trials evaluating the clinical complication and survival rates of indirect restorations bonded to tooth substrate sealed immediately after preparation with suitable resin bonding. The extracted data were analyzed via Review Manager 5.4 for meta-analysis (α=.05).

RESULTS

A total of 11 studies were included in this review. The clinical complication rate was lower for immediately sealed dentin than for protocols without dentin sealing. The survival rate of restorations luted with the immediate dentin sealing protocol was higher (96.4% to 100%) than that of immediate dentin sealing (81.8% to 96.7%), negatively correlated with the observation time. The intensity and incidence of postoperative sensitivity were statistically significantly lower for restorations with immediate dentin sealing than for those without dentin sealing or conventionally cemented (P<.05).

CONCLUSIONS

Immediate dentin-sealed indirect restorations had fewer clinical complications and higher success and survival rates than those delivered without dentin sealing. To avoid postoperative sensitivity or reduce its intensity, dentin surfaces should be sealed immediately after preparation. More long-term randomized clinical trials are recommended to confirm these evidence-based conclusions.

Evaluation of the ceramic laminate veneer-tooth interface after different resin cement excess removal techniques

OBJECTIVES

To compare, in vitro, resin cement excess removal techniques at the veneer-tooth interface.

MATERIALS AND METHODS

Anterior human teeth were restored with ceramic veneers and randomly divided according to the following techniques (n = 10): removal of excess resin cement with brush and dental floss, followed by light-curing with Valo (Group 1) or Elipar (Group 2) for 1 min and 40 s; tack-curing with Valo (Group 3) or Elipar (Group 4) for 1 s; and tack-curing with Valo (Group 5) or Elipar (Group 6) for 5 s. The tack-curing was followed by removal of excess with probe and dental floss and light-curing for 1 min and 40 s. The area of excess resin cement (mm2) was measured in micro-CT images using AutoCAD program. The failures at the cervical margin in the X, Y, and Z axes (µm) of greater value were measured using the DataViewer program. The specimens were submitted to microleakage with 2% basic fuchsin.

RESULTS

According to the Kruskal-Wallis and multiple comparison test, the highest area of excess resin cement was found in Group 1 (5.06 mm2), which did not differ statistically from Groups 2 (3.70 mm2) and 5 (2.19 mm2). Groups 2, 3 (1.73 mm2), 4 (1.14 mm2), and 5 (2.18 mm2) did not differ statistically. Group 6 (0.77 mm2) obtained the lowest value, which did not differ statistically from Groups 3 and 4. According to the Kruskal-Wallis and Dunn test, there was no significant difference in failures in X (p = 0.981), Y (p = 0.860), and Z (p = 0.638) axes and no significant difference in microleakage (p = 0.203) among the groups.

CONCLUSIONS

Tack-curing for 1 s or 5 s, followed by removal of excess resin cement using a probe and a dental floss, tended to result in a lower amount of excess material around the margin.

CLINICAL RELEVANCE

The technique used for resin cement excess removal influences the amount of excess leaved at the veneer-tooth interface. Tack-curing for 1 s or 5 s is recommended to mitigate the excess resin cement.

Efficacy of two polishing systems in reestablishing the surface smoothness of posterior monolithic lithium disilicate restorations: One-year results of a split-mouth randomized controlled clinical trial

STATEMENT OF PROBLEM

Selecting the optimal polishing procedure to reestablish surface smoothness after occlusal adjustment is essential for the long-term success of glass-ceramic restorations. While in vitro studies have shown different effective polishing protocols, clinical trials are lacking.

PURPOSE

The purpose of this split-mouth controlled clinical trial was to evaluate the effectiveness of 2 polishing systems in reestablishing the surface smoothness of posterior monolithic lithium disilicate ceramic restorations.

MATERIAL AND METHODS

Ninety-six restorations that required occlusal adjustment after bonding were randomized into 2 groups: Forty-eight restorations were polished by using the Exa Cerapol polishing kit, and the other 48 restorations were polished by using the Shofu polishing kit. The restorations were replicated with epoxy resin at 3 study times-after bonding (t1), after occlusal adjustment (t2), and after polishing (t3)-for quantitative roughness analysis (Ra). Representative specimens from each group were qualitatively analyzed by using a confocal laser microscope. Clinical analyses were performed after the polishing procedure and at 30, 180, and 365 days after the polishing procedure by following the United States Public Health Service (USPHS) criteria. ANOVA and the Tukey multiple comparisons parametric tests were computed (α=.05). The Kaplan-Meier test was used to analyze the survival rate of restorations.

RESULTS

No statistically significant difference was found between the Exa Cerapol and Shofu groups (P=.086). A statistically significant difference was found between study times t1 and t2 and between t2 and t3 (both P<.001) in both experimental groups. No statistically significant difference was found between study times t1 and t3 (P=.181) in either experimental group. For the clinical criterion "integrity of restorations," all the elements analyzed indicated an alfa grade at all study times. The survival rate of the restorations was 100%.

CONCLUSIONS

Both polishing kits were effective in reestablishing the surface smoothness of restorations after occlusal adjustment.

Clinical Performance of Minimally Invasive Monolithic Ultratranslucent Zirconia Veneers: A Case Series up to Five Years of Follow-up

There is a lack of reports in the literature on the long-term clinical performance of ultratranslucent zirconia, especially considering its use in manufacturing monolithic veneers. The purpose of this case series is to describe the aesthetic treatment steps of three patients with minimally invasive ultratranslucent zirconia veneers and to report the clinical findings up to five years. Three patients (woman: 2, man: 1; mean age: 30 years) unsatisfied with their dental aesthetics sought dental treatment. The treatment plan involved cementing ultratranslucent zirconia veneers. Air-abrasion was performed on the internal surface of zirconia with alumina particles coated by silica (silicatization), followed by silane and adhesive applications for the adhesive cementation. All veneers were adhesively cemented to enamel with resin cement (Variolink Esthetic, Ivoclar). The patients were clinically evaluated annually considering the Ryge modified/ California Dental Association criteria. After a mean follow-up of 4.33 years (4-5 years), a survival rate of 100% was detected for the 28 minimally invasive ultratranslucent zirconia veneers cemented in the 3 patients. There were no absolute failures such as debonding, veneer fracture, or secondary caries. Superficial marginal discoloration was observed in one element (maxillary left lateral incisor) of one patient. Ultratranslucent zirconia is a viable option for manufacturing veneers due to its excellent clinical performance and longevity. However, further long-term clinical studies are essential to consolidate this material as an option for esthetic restorations.

Veneer crowns in anterior endodontically-treated teeth: A case report with 1-year follow-up

Key Clinical Message

Veneer crowns can be used in anterior endodontically-treated teeth with light occlusal force and enamel substrate consideration as a more conservative approach instead of conventional all ceramic crowns.

Abstract

All-ceramic anterior crowns and veneers have been used widely in dentistry with high clinical success rate. The development of new reinforced ceramics in recent years has led to more use of extended defect-oriented preparation designs, that is, extended veneers, instead of full crown preparations which are less invasive. A veneer crown is simply a veneer that covers the entire tooth. The preparation preserves remaining enamel and uses a conservative preparation design. Its indication should be carefully raised taking into consideration various factors. The preparation design is crucial to ensure longevity of such restoration. The balance is between sufficient preparation for the material thickness and adequate strength against occlusal load and the enamel preservation. A 24-year-old man referred to the restorative department of the Dentistry School of Tehran University of Medical Sciences complaining from his poor esthetics in the maxillary incisors. In clinical and radiographic evaluation, he had open bite, composite discoloration due to corrosion of the pre-fabricated posts in all four incisors, a periapical lesion in tooth 21 and under-filled root canal therapy in tooth 22. All four posts and composite restorations were removed and teeth 21 and 22 were retreated. Although the amount of remaining tooth tissue was low, it had enough enamel thickness, especially in the buccal area. Taking into consideration this mixed enamel and dentin substrate, endodontics access, esthetics needs and canine guidance occlusion with no parafunction history, bonded lithium disilicate veneer crowns were selected to restore the maxillary incisors. A 12-month follow-up showed promising clinical (healthy gingival tissue and successful restorations) and radiographic (reduced periapical lesion) outcomes.

Effect of preparation design on fracture strength of compromised molars restored with lithium disilicate inlay and overlay restorations: An in vitro and in silico study

PURPOSE

The objective of this study was to determine the influence of different preparation designs on the fracture strength, failure type, repairability, formation of polymerization-induced cracks, and tooth deformation of structurally compromised molars restored with lithium disilicate inlays and overlays in combination with Immediate Dentin Sealing (IDS).

MATERIAL AND METHODS

Human molars (N = 64) were randomly assigned to four different preparation designs: Undermined Inlay (UI), Extended Inlay (EI), Restricted Overlay (RO), and Extended Overlay (EO). The teeth were restored using lithium disilicate partial restorations and subjected to thermomechanical fatigue in a chewing simulator (1,2 × 10 (Mondelli et al., 2007) cycles on 50 N, 8000x 5-55 °C), followed by load to failure testing. In silico finite element analysis was conducted to assess tooth deformation. Polymerization-induced cracks were evaluated using optical microscopy and transillumination. Fracture strengths were statistically analyzed using a Kruskal-Wallis test, while the failure mode, repairability, and polymerization cracks were analyzed using Fisher exact test.

RESULTS

The propagation of polymerization-induced cracks did not significantly differ among preparation designs. All specimens withstood chewing simulator fatigue, with no visible cracks in teeth or restorations. Fracture strength was significantly influenced by preparation design, with restricted overlay (RO) showing higher fracture strength compared to extended inlay (EI) (p = .042). Tooth deformation and fracture resistance correlated between in vitro and in silico analyses). UI exhibited a statistically less destructive failure pattern than EO (p < .01) and RO (p = .036). No statistically significant influence of the preparation design on repairability was observed. Groups with higher repairability rates experienced increased tooth deformation, leading to less catastrophic failures.

CONCLUSIONS

The preparation design affected the fracture strength of compromised molars restored with lithium disilicate inlays and overlays, with significantly lower fracture strength for an extended inlay. The failure pattern of lithium disilicate overlays is significantly more destructive than that of undermined and extended inlays. The finite element analysis showed more tooth deformation in the inlay restorations, with lower forces in the roots, leading to less destructive fractures. Since cusp coverage restorations fracture in a more destructive manner, this study suggests the undermined inlay preparation design as a viable option for restoring weakened cusps.

Clinical longevity of intracoronal restorations made of gold, lithium disilicate, leucite, and indirect resin composite: a systematic review and meta-analysis

OBJECTIVES

The aim of this systematic review and meta-analysis is to assess the comparative clinical success and survival of intracoronal indirect restorations using gold, lithium disilicate, leucite, and indirect composite materials.

MATERIAL AND METHODS

This systematic review and meta-analysis were conducted following the Cochrane Handbook for Systematic Reviews of Interventions and PRISMA guidelines. The protocol for this study was registered in PROSPERO (registration number: CRD42021233185). A comprehensive literature search was conducted across various databases and sources, including PubMed/Medline, Embase, Cochrane Library, Web of Science, ClinicalTrials.gov, and gray literature. A total of 7826 articles were screened on title and abstract. Articles were not excluded based on the vitality of teeth, the language of the study, or the observation period. The risk difference was utilized for the analyses, and a random-effects model was applied. All analyses were conducted with a 95% confidence interval (95% CI). The calculated risk differences were derived from the combined data on restoration survival and failures obtained from each individual article. The presence of heterogeneity was assessed using the I2 statistic, and if present, the heterogeneity of the data in the articles was evaluated using the non-parametric chi-squared statistic (p < 0.05).

RESULTS

A total of 12 eligible studies were selected, which included 946 restorations evaluated over a minimum observation period of 1 year and a maximum observation period of 7 years. Results of the meta-analysis indicated that intracoronal indirect resin composite restorations have an 18% higher rate of failure when compared to intracoronal gold restorations over 5-7 years of clinical service (risk difference =  - 0.18 [95% CI: - 0.27, - 0.09]; p = .0002; I2 = 0%). The meta-analysis examining the disparity in survival rates between intracoronal gold and leucite restorations could not be carried out due to methodological differences in the studies.

CONCLUSIONS

According to the currently available evidence, medium-quality data indicates that lithium disilicate and indirect composite materials demonstrate comparable survival rates in short-term follow-up. Furthermore, intracoronal gold restorations showed significantly higher survival rates, making them a preferred option over intracoronal indirect resin-composite restorations. Besides that, the analysis revealed no statistically significant difference in survival rates between leucite and indirect composite restorations. The short observation period, limited number of eligible articles, and low sample size of the included studies were significant limitations.

CLINICAL SIGNIFICANCE

Bearing in mind the limitations of the reviewed literature, this systematic review and meta-analysis help clinicians make evidence-based decisions on how to restore biomechanically compromised posterior teeth.

Clinical survival of No-prep indirect composite laminate veneers: a 7-year prospective case series study

BACKGROUND

The no preparation technique which is a reversible form of treatment characterized by the absence of tooth tissue preparation and preserves the soft tissue architecture while preserving all natural tooth structures is indicated in cases where the tooth structure allows material to be added. The aim of this study is to evaluate the clinical performance and survival rates of indirect composite laminate veneers with no preparation after 7 years.

MATERIALS AND METHODS

A total of 80 indirect composite veneers were placed on maxillary anterior teeth in 35 patients (n = 80). Diastema (n = 64), wedge tooth anomalies (n = 9) and re-shaping (n = 7) were the main indications for veneer treatments. All laminate veneers were fabricated with an indirect microhybrid composite material (Gradia, GC Dental). No tooth preparation was performed. Light-cured resin cement (Choice 2, Bisco) was used to lute the veneers. Composite veneers were evaluated using Modified United States Public Health Service criteria. Survival rates of the veneers were calculated using Kaplan-Meier statistics. The data containing the results of the USPHS criteria at baseline, 2 years and 7 years was statistically analyzed using Wilcoxon Signed Rank test at the 0.05 level of significance.

RESULTS

The overall survival rate was 91.3%. After 7 years, 7 absolute failures including 4 debonding (marginal adaptation, score 4) and 3 fractures (fracture of restoration, score 3) were noted. Color match was scored as 1 (n = 34) and 2 (n = 15). Slightly rough surfaces (41 of 73 laminates) and slight marginal discoloration (15 of 73 laminates) were noted. The overall scores after 84 months were significantly higher than the baseline scores for the marginal adaptation (p = 0.008), color match (p = 0.000), marginal discoloration (p = 0.000), surface roughness (p = 0.000), and fracture of restoration (p = 0.001) criteria.

CONCLUSIONS

In this study, indirect composite veneers without any preparation on maxillary anterior teeth showed acceptable performance in terms of both survival rate and quality of restorations. This procedure offers a predictable and successful treatment that ensures maximum preservation of the intact tooth.

Partial Ceramic Veneer Technique for Challenging Esthetic Frontal Restorative Procedures

Frontal darkened teeth have shown to be one of the most challenging treatments for esthetic dentistry in recent years. This case report, along with a 30-month follow-up, describes the application of a partial ceramic veneer, restricted to the mid-cervical third region, made in the upper left central incisor darkened by trauma. The procedure consisted of maintenance of the entire incisal face, as well as esthetic and morphological rehabilitation of the smile line with veneers and ultra-thin partial ceramic veneers. The planning process was thoroughly elaborated by photographs, study models, a virtual smile designed, diagnostic waxing, and reproduction in the patient's mouth through mock-up. Following, dental home bleaching, esthetic gingival contouring, and minimally invasive tooth preparation were performed. Two types of glass ceramics (lithium disilicate and feldspathic) were used in different regions due to the peculiar characteristics of resistance, finishing, and polishing. According to the present case report, preparing a cervical partial ceramic veneer is an innovative, viable, and safe approach to maintaining the incisal portion of the tooth preserved and setting a detailed tooth morphology/color. The application of partial ceramic veneer provides incisal edge preservation and simplifies the reproduction of the adjacent tooth characteristics, avoiding multiple esthetic appointments.

Biaxial flexure strength and physicochemical characterization of a CAD/CAM lithium disilicate ceramic: effect of etching time, silane, and adhesive applications

OBJECTIVE

To evaluate the effect of different acid etching time and bonding agent (silane and/or adhesive system) on biaxial flexural strength and physico-chemical properties of a lithium disilicate ceramic.

MATERIAL AND METHODS

One hundred twenty ceramic discs were made and divided into 8 groups (n = 15) according to factors "etching time" (20 and 120 s) with hydrofluoric acid (HF) and "bonding agent" (C, no bonding agent; S, silane, A, adhesive; and SA, silane + adhesive). After surface treatment, a resin cement layer was applied to the surface and all specimens were subjected to biaxial flexural strength (BFS) test with treated surfaces loaded in tension (1 mm/min). The Weibull analyses and complementary analyses were also performed. Statistical analysis was done with 2-way ANOVA and the Tukey test (α = 0.05).

RESULTS

ANOVA revealed that the factors "etching time" (p = 0.0003) and "bonding agent" (p = 0.007) were statistically significant. In the overall analysis, the HF120S group (272.02 ± 35.30A MPa) presented significantly higher BFS than that of HF120C (218.45 ± 17.15CD MPa) and HF20S (228.40 ± 37.83BCDMPa). On the other hand, the HF20A group (208.92 ± 31.16D MPa) had significantly lower BFS than HF120S (272.02 ± 35.30A), HF120A (254.42 ± 26.87ABC) and HF120SA (259.30 ± 36.55AB) groups (Tukey). The Weibull modulus (m) of all groups was significantly different from each other (p = 0.000).

CONCLUSIONS

Regardless of etching time, the application of silane alone is sufficient to increase the flexural strength of glass ceramic, eliminating the need for the application of adhesive systems. Moreover, if only silane or adhesive is applied, 120-s HF application should increase the flexural resistance of the lithium disilicate ceramic.

CLINICAL SIGNIFICANCE

Applications of adhesive systems after silanization can be suppressed from the surface treatment protocol of glass ceramics, since it does not improve their mechanical strength.

8-year multicenter retrospective study on partial laminate veneers

PURPOSE

This retrospective study aimed to evaluate the survival and success rates of ceramic partial laminate veneers. Scanning electron microscopy was used to evaluate fractures and marginal defects.

METHODS

In total, 31 patients received 79 partial laminate veneers on the maxillary anterior teeth. After adhesive luting, restorations were evaluated by calibrated clinicians for up to eight years using modified United States Public Health Service (USPHS) criteria. In addition, epoxy resin replicas were fabricated from silicone impressions and analyzed using scanning electron microscopy. Survival analyses were performed using the Kaplan-Meier and log-rank tests (α = 0.05). Success was analyzed in percentages by comparing the baseline and last follow-up.

RESULTS

The cumulative survival rates were 100% after 1 year; 95.9% (SE 2.8%) after 5 years; and 61.4% (SE 25.3%) after 8 years. No significant differences (P > 0.05) were observed between functional and non-functional restorations. Changes in the USPHS criteria evaluation were only observed for adaptation: 12.5% (SE 4.7%), marginal discoloration: 4.2% (SE 3.0%), color match: 4.2% (SE 3.0%), and fractures: 16.7% (SE 5.3%). Scanning electron microscopy evaluations revealed undetected initial cracks and deficiencies in the restorations.

CONCLUSION

Partial laminate veneers displayed good survival rates during the long-term follow-up. The main problems observed were related to the quality of the margins, color mismatch, and restoration integrity. However, in most cases, restoration replacement was not required.

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

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).

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.

Clinical Evaluation of Lithium Disilicate Veneers Manufactured by CAD/CAM Compared with Heat-pressed Methods: Randomized Controlled Clinical Trial

CLINICAL RELEVANCE

Lithium disilicate veneers for esthetic restorations show great accuracy and similarity, regardless of the type of fabrication technique.

SUMMARY

Long-Term Survival and Complication Rates of Porcelain Laminate Veneers in Clinical Studies: A Systematic Review

The presented study aimed to assess the survival rate of porcelain laminate veneers (PLV) based on a systematic review of the literature. An electronic search was last updated in February 2021. Eligibility criteria included clinical series of patients rehabilitated with PLVs published in the last 25 years, with a minimum follow-up of 3 years. Survival analysis methods were applied. Twenty-five studies were included, with 6500 PLVs. The 10-year estimated cumulative survival rate (CSR) of PLVs was 95.5%. The 10-year CSR of PLVs when fracture, debonding, occurrence of secondary caries, and need of endodontic treatment were considered as isolated reasons for failure were 96.3%, 99.2%, 99.3%, and 99.0%, respectively. PLVs without incisal coverage had a higher failure rate than PLVs with incisal coverage. Non-feldspathic PLVs performed better than feldspathic PLVs. As a conclusion, the 10-year CSR of PLVs was 95.5%, when fracture, debonding, occurrence of secondary caries, and need of endodontic treatment were considered as reasons for restoration failure. Fracture seems to be most common complication of PLVs, followed by debonding, with both more commonly happening within the first years after PLV cementation. PLVs with incisal coverage and non-feldspathic PLVs presented lower failure rates than PLVs without incisal coverage and feldspathic PLVs.

Clinical outcomes of minimally invasive ceramic restorations executed by dentists with different levels of experience. Blind and prospective clinical study

PURPOSE

To evaluate the clinical outcomes of minimally invasive ceramic restorations executed by dentists with different levels of experience.

METHODS

Sixteen professionals were divided into 4 groups according to their experience levels. These included G1: up to 2 years since graduation, G2: 2-5 years, G3: 5-10 years, and G4: more than 10 years. All professionals were trained to follow the same standardized clinical protocol, but were unaware of the research objectives. A single evaluator followed the clinical treatments and recorded the complications and errors that occurred during the execution of the protocol. Ninety-one full crowns, 137 veneers, and 46 no-preparation veneers were prepared from lithium disilicate. Follow-ups were performed immediately and at 30, 180, and 360 days after the cementation and the evaluation based on the modified United States Public Health Service criteria. Ceramic chipping/fracture and debonding were considered failures. Fractures were replicated and submitted to fractographic analysis.

RESULTS

The highest number of failures were found in G1 followed by G3 and the lowest number of failures were found in G2. The level of success was 94% after 360 days. The fractographic analysis demonstrated the external surface of restorations as the critical area and suggested that failures might occur due to noncompliance with the clinical protocol. There was no correlation between professional experience and number of failures or patient satisfaction.

CONCLUSIONS

Professional experience was not a decisive for patient satisfaction and success of minimally invasive ceramic restorations, and noncompliance with the clinical protocol was associated with early ceramic restoration failures.

Curing potential and color stability of different resin-based luting materials

PURPOSE

To determine the curing potential and color stability of resin-based luting materials for aesthetic restorations.

MATERIAL AND METHODS

Four resin-based luting agents were tested: traditional dual-activated resin cement (RelyX ARC, ARC), amine-free dual-activated resin cement (RelyX Ultimate, ULT), light-activated resin cement (RelyX Veneer, VEN), and pre-heated restorative resin composite (Filtek Supreme, PHC). Degree of C=C conversion was determined by infrared spectroscopy (n=3) with direct light exposure or with interposition of 1.5-mm-thick ceramic (e.max Press HT) between the luting material and light. The curing potential considered the ratio between these two scenarios. Color difference (n=6) was determined by CIELAB (ΔE_ab) and CIEDE2000 (ΔE₀₀) methods, by spectrophotometer measurements made 24h after photoactivation and 90 days after storage in water. Data was submitted to ANOVA and Tukey's test (α=0.05).

RESULTS

The luting agents affected both conversion and color stability. With ceramic, ARC produced the highest conversion among the tested groups (75±1%) and the pre-heated composite (PHC) the lowest one (51±3%), but the curing potential was similar for all materials. ULT produced lower ΔE_ab than ARC. PHC presented the lowest color difference when considered both CIELAB and CIE2000 methods (ΔE_ab 2.1±0.4; ΔE₀₀ 1.6±0.2).

SIGNIFICANCE

All luting strategies presented high curing potential. Amine-free dual-activated material was able to reduce color difference than that formulated with the amine component. Pre-heated composite produced the least color variation after storage.

Spectrophotometric evaluation of color errors generated in the visual color duplication procedure for current ceramic veneers

Background/purpose

Color errors associated with the visual color duplication approach for ceramic laminate veneers are still challenging in esthetic dentistry. The aim of this study is to evaluate color errors generated during traditional visual shade matching approach.

Materials and methods

Eighteen stooth-shaped veneer discs (shade A2 and 0.7 mm in thickness) were fabricated using six veneer materials. The veneer specimens placed on five extracted teeth with nominal shade A2 formed veneer-tooth combinations. Color coordinates of the A2 shade tab, the extracted teeth, and the veneer-tooth combinations were measured using a spectrophotometer. Then, the veneers were reduced to 0.5 mm, and 0.3 mm in thickness consecutively. Color measurements were performed repeatedly. Color differences of the extracted teeth to veneer-tooth combinations (ΔEt-v), veneer-tooth combinations to shade tab (ΔEv-s), and translucency parameter (TP) values were calculated and analyzed using Two-way ANOVA.

Results

ΔEt-v ranged from 2.0937 to 5.0603 (mean of 3.1833±1.5485). Mean of ΔEv-s was 4.0103±1.8508. ΔEt-v and ΔEv-s values were significantly influenced by veneer material and thickness (P<0.05). TP values decreased gradually with the lessening of veneers thickness.

Conclusion

Acceptable color duplication of ceramic veneers cannot be achieved by routine visual shade replica protocols, when the thickness of veneers is less than 0.7 mm. Specified color matching standards for the ceramic veneers are needed.

Effect of luting materials, presence of tooth preparation, and functional loading on stress distribution on ceramic laminate veneers: A finite element analysis

STATEMENT OF PROBLEM

How the polymerization shrinkage, loading, and mechanical properties of luting materials affect the shrinkage and functional stresses in ceramic laminate veneers (CLVs) with and without tooth preparation is unclear.

PURPOSE

The purpose of this finite element analysis (FEA) study was to evaluate the effect of the polymerization shrinkage, functional loading, and mechanical properties of different luting materials on the stresses in ultrathin 0.3-mm CLVs with and without tooth preparation.

MATERIAL AND METHODS

Three resin cements, RelyX Veneer (RV), Allcem Veneer APS (AV), Variolink Esthetic LC (VE), and 1 flowable composite resin, Tetric N-Flow (TF), were tested for post-gel shrinkage (Shr), Knoop hardness (KHN), elastic modulus (E), compressive strength (CS), and diametral tensile strength (DTS). IPS e.max CAD disks of 0.3-mm thickness were made for simulating the effects of light attenuation. Eight 2-dimensional finite element models (Marc-Mentat) of a maxillary central incisor were generated to evaluate the polymerization shrinkage stress of different materials for luting 0.3-mm CLVs with or without tooth preparation and the stress during functional loading by using a modified von Mises criterion (mvm). Collected data from Shr, KHN, and E were submitted to 2-way ANOVA and the Tukey HSD test (α=.05).

RESULTS

Light attenuation by the 0.3-mm ceramic disk did not significantly affect the E values, but Shr was significantly lower in VE (26%) and TF (35%). TF had lower volumetric Shr (%) when interposing a ceramic disk (0.31%). Both tested tooth preparation options showed similar stress distributions from polymerization shrinkage or functional loading, with higher stress concentration on the incisal edge and also on the cervical surface. The model featuring tooth preparation and RV resin cement had the highest and VE the lowest stress levels.

CONCLUSIONS

The flowable composite resin had similar mechanical properties as the resin cements. The stress distribution from shrinkage and functional loading was similar for both techniques with or without tooth preparation.

Three-dimensional analysis of the relationship between the structure of maxillary central incisor and the preparation of dental all-ceramic

The purpose of this study is to investigate the interrelationship between tooth preparation and dental structure of Chinese maxillary central incisors and provide scientific guidance for clinical all-ceramic restoration. Forty-five specimens of maxillary central incisors were fabricated by 3D printer based on data of Micro CT scanning. Subsequently, every three specimens from the same natural tooth were randomly divided into three groups (n = 15): porcelain veneer, all ceramic crown, and the blank control group. All the specimen teeth were prepared according to routine clinical criteria, reconstructed into 3D models and then measured in software. The results showed that the mean quantity of reduction (volume fraction) was (28.35 ± 4.37) % and (56.93 ± 3.47) % for porcelain veneer and all-ceramic crown, respectively. The bonding areas of different all-ceramic restorations were (128.85 ± 11.73) mm2 and (97.15 ± 9.98) mm2 for all-ceramic crown and porcelain veneer respectively. In porcelain veneer group, the area of enamel adhesive was (54.80 ± 12.70) mm2, and the area of dentin was (42.35 ± 9.62) mm2. As the results of the one-sample t test, the mean distances from medullary angle to incisal edge or adjacent surface have significant differences with the test value which was set as 0.5 (P < .05). The reduction of the tooth for porcelain veneer is less than that of ceramic crown and the cementation of porcelain veneer is mostly dependent on the conservation of the enamel during preparation. The region from mesial adjacent surface to mesiopulpal angle is prone to have the problem of medullary perforation.

The Effect of Fractional CO2 Laser Irradiation on Shear Bond Strength of Resin Cement to Feldspathic Porcelain

Introduction: This study investigated the effect of fractional CO2 laser on shear bond strength (SBS) of resin cement to feldspathic porcelain. Methods: Sixty blocks of unglazed feldspathic porcelain were randomly divided into 5 groups of 12 by treatment. Group 1 and 2 underwent etching with 9.6% hydrofluoric acid (HF) and air abrasion with alumina particles, respectively. In groups 3 and 4, a fractional CO2 laser was applied for 10 seconds using 20 W/10 mJ (group 3) or 15 W/20 mJ (group 4). The specimens in group 5 were first treated by fractional CO2 laser (15 W/20 mJ) and then etched by HF acid. After silane application, a resin cement (Clearfil SA) was poured into plastic molds over the porcelain surface and light cured. SBS was assessed by a universal testing machine and the type of bond failure was determined. Results: Analysis of variance (ANOVA) indicated a significant difference in SBS among the study groups (P<0.001). Pairwise comparison demonstrated that the application of fractional CO2 laser followed by HF acid yielded SBS that was significantly greater than that of the other groups (P<0.05). The SBS of both laser groups (groups 3 and 4) were comparable to each other and significantly lower than the other groups (P<0.05). No significant difference was found in the distribution of failure modes among the groups (P=0.522) Conclusion: The application of fractional CO2 laser followed by HF acid treatment can improve SBS of resin cement to feldspathic porcelain and could be recommended when demanding extra retention.

Fracture Resistance of Ceramic Laminate Veneers Bonded to Teeth with Class V Composite Fillings after Cyclic Loading

Purpose

Porcelain laminate veneers (PLVs) are sometimes required to be used for teeth with composite fillings. This study examined the fracture strength of PLVs bonded to the teeth restored with different sizes of class V composite fillings.

Materials and Methods

Thirty-six maxillary central incisors were divided into three groups (n=12): intact teeth (control) and teeth with class V composite fillings of one-third or two-thirds of the crown height (small or large group, resp.). PLVs were made by using IPS e.max and bonded with a resin cement (RelyX Unicem). Fracture resistance (N) was measured after cyclic loading (1 × 10⁶ cycles, 1.2 Hz). For statistical analyses, one-way ANOVA and Tukey test were used (α=0.05).

Results

There was a significant difference between the mean failure loads of the test groups (P=0.004), with the Tukey-HSD test showing lower failure loads in the large-composite group compared to the control (P=0.02) or small group (P=0.05). The control and small-composite groups achieved comparable results (P > 0.05).

Conclusions

Failure loads of PLVs bonded to intact teeth and to teeth with small class V composite fillings were not significantly different. However, extensive composite fillings could compromise the bonding of PLVs.

Effect of Preparation Designs on the Prognosis of Porcelain Laminate Veneers: A Systematic Review and Meta-Analysis

Objective:

To investigate the association between preparation designs and prognosis of porcelain laminate veneers (PLVs).

Methods:

Electronic and manual literature searches were performed in Medline, Embase, CENTRAL, and Scopus databases for randomized controlled trials and retrospective and prospective cohort studies comparing any two of three preparation designs. The quality of the included studies was assessed using the Newcastle-Ottawa scale. Pooled hazard ratios and risk ratios were used to evaluate the difference between two preparation designs. Subgroup analyses, sensitivity analysis, and evaluation of publication bias were performed if possible.

Results:

Of 415 screened articles, 10 studies with moderate to high quality were included in the meta-analysis. Comparison of preparations with incisal coverage to preparations without coverage revealed a significant result based on time-to-event data (hazard ratio=1.81, 95% confidence interval [CI]=1.18-2.78, I2=12.5%), but the result was insignificant based on dichotomous data (risk ratio=1.04, 95% CI=0.59-1.83, I2=42.3%). The other comparisons between any two of overlap, butt-joint, and window types revealed no statistically significant difference. Subgroup analyses regarding the porcelain materials, location of prosthesis, and tooth vitality could account for only part of the heterogeneity. No evidence of publication bias was observed.

Conclusions:

Within the limitation of the present study, it can be concluded that preparation design with incisal coverage for PLVs exhibits an increased failure risk compared to those without incisal coverage. The failure risk of the overlap type may be higher than the butt-joint type but must be validated in further studies.

Effect of luting agent on the load to failure and accelerated-fatigue resistance of lithium disilicate laminate veneers

OBJECTIVE

The aim of this study was to investigate the influence of the luting agent on the application of laminate veneers (LVs) in an accelerated fatigue and load-to-failure test after thermo-cyclic aging.

METHODS

Sound maxillary central incisors (N=40) were randomly divided into four groups to receive LVs (Li₂Si₂O₅) that were adhesively bonded: Group CEMF: Adhesive cement (Variolink Esthetic LC), fatigue test; Group CEMLF: Adhesive cement, load-to-failure test; Group COMF: Resin composite (Enamel HFO), fatigue test; Group COMLF: Resin composite, load-to-failure test. The specimens were thermo-mechanically aged (1.2×10⁶ cycles at 1.7Hz/50N, 8000 cycles 5-55°C) and then subjected to either accelerated fatigue (5Hz, 25N increasing after each 500 cycles) or load to failure (1mm/min). Failure types were classified and data analyzed using chi-square, Kaplan Meier survival, Log Rank (Mantel-Cox) and independent-samples t-test.

RESULTS

After thermo-mechanical aging, fracture resistance (p<0.000) was higher in the composite groups. Kaplan Meier survival rates showed significant difference (p<0.001) between the composite (mean load: 1165N; mean cycles: 22.595) and the cement groups (mean load: 762.5N; mean cycles: 14.569). The same differences were observed in the load to failure test (cement M=629.4N, SD±212.82 and composite M=927.59N, SD±261.06); t (18)=-2.80, p=0.01. Failure types were observed as fractures and chipping in group CEMF, all other groups were predominantly adhesive failures between the luting agent and the laminate veneer.

SIGNIFICANCE

The delivery of laminate veneers using a direct restorative composite rather than a resin cement resulted in significantly less chipping and fractures, higher fracture strength in both accelerated fatigue and load-to-failure.

Severe tetracycline dental discoloration: Restoration with conventional feldspathic ceramic veneers. A clinical report

The treatment of severe tetracycline discoloration is a challenge for the dentist. There are several treatment options and one of the most effective is the use of feldspathic veneers. The aim of this clinical case was to carry out the replacement with conventional feldspathic ceramic veneers on a patient with highly stained teeth (grade IV tetracycline) by a minimally invasive approach. Clinical examination revealed gingival retraction, color change of the veneers, ceramic cracked of 1.1 and 1.3 and incisal wear in lower anterior teeth. The decision was to retreat with feldspathic ceramic veneers from 1.6 to 2.6. Premolars and first molars were included because its dark color intensifies the width buccal corridors. Also, the restoration with veneers from 3.3 to 4.3 was considered. Firstly, the veneers were removed and the color was selected by the Vitapan 3D Master guide (Vita Zahnfabrick, Bad Säckingen, Germany). Mock-up was made to evaluate aesthetic, phonetic and functional parameters. Then, teeth were prepared through the mock-up in order to reduce the minimal amount of dental tissue possible. Opaque dentine mass of microhybrid composite (Esthet-X A2O, Dentsply Sirona, Konstanz, Germany) was placed to mask the most intense stains. The definitive impressions were taken with silicone (Aquasil Ultra XLV, Dentsply Sirona, Konstanz, Germany) were taken to fabricate conventional feldsphatic ceramic veneers (Noritake kisai Co, Ltd. Japan) by the parallel stratification masking technique. For cementing, an opaque cement was selected from the try-in tests (Calibra, Dentsply Sirona, Konstanz, Germany) and the composite was silicatized with an air-abrasion device. A favorable and minimally invasive result was achieved to treat grade IV tetracycline stains, surpassing the patient’s aesthetic expectations and functional needs.

Key words:Porcelain veneer, tetracycline teeth, minimally invasive, masking, opaque composite.

Effectiveness of high-power LEDs to polymerize resin cements through ceramics: An in vitro study

STATEMENT OF PROBLEM

The cementation of ceramic veneers using light-polymerized resin cement is largely dependent on the proper light activation of the cement. Light activation using high irradiance could shorten the time required to lute multiple restorations.

PURPOSE

The purpose of this in vitro study was to evaluate the light transmission of dental light-polymerizing units through ceramic cylinders and its effect on the polymerization kinetics of a resin cement.

MATERIAL AND METHODS

Ceramic ingots (IPS Empress Esthetic, shade ET1) were sectioned to produce cylinders 0.5, 1.0, and 2.0 mm thick. Two light-emitting diode units were evaluated: SmartLite Focus and Valo Cordless, the latter used in either Standard or Xtra Power (XP) modes. Light transmission (average of irradiance, total energy, and light-emission profile) through the cylinders was measured (n=3). The polymerization kinetics of a resin cement light polymerized through the ceramic was monitored for 5 minutes (n=3). The degree of conversion was measured again after 72 hours. Data were individually analyzed with 2-way ANOVA and the Tukey HSD test (α=.05).

RESULTS

Valo at XP presented the highest values of irradiance and SmartLite the lowest, irrespective of the ceramic thickness. Regarding the total energy, XP showed the lowest values. The total energy and irradiance lessened with the increase in ceramic thickness. In general, except for Valo at XP, the ceramic thickness did not affect the degree of conversion. Valo at XP and interposing 2.0 mm ceramic resulted in the lowest values of Rp_max.

CONCLUSIONS

The reduction of total energy and irradiance by ceramic interposition had only a slight effect on polymerization kinetics.

Comparing marginal microleakage of three different dental materials in veneer restoration using a stereomicroscope: an in vitro study

Objectives:

The objectives were to evaluate the degree of dye penetration of three different dental materials as esthetic veneer restorations on anterior teeth using stereomicroscope, and to provide reference for clinical choice.

Materials and Methods:

Sixty freshly extracted human maxillary central incisors were selected and randomly divided into three main groups of 20 each. Respectively, the teeth were prepared for veneer restoration by fiber-reinforced composite (FRC) (Everstick NET, Stick Tech), porcelain laminate veneer (PLV) (IPS Empress II(E-Max Press)) and 3M composites (3M ESPE) bonding with G-Cem resin cement (GC). After exposed to thermocycling (500cycles per day (5–55 °C, intervals: 30 s)) and immersed in 2% basic fuchsin dye solution for 24 h, the specimens were then sectioned buccolingual into three halves in a vertical plane parallel and measured dye penetration using stereomicroscope (Zeiss). The data collected was recorded by the dye penetration index (0–5) and statistically analysed using one-way analysis of variance (ANOVA) and T-tests using SPSS 13.

Results:

It is evident that the FRC group showed the lowest mean score of 0.333 mm, and the PLV group showed a highest mean score of 0.749 mm, as compared with the FRC group and the 3M composites group. Overall, when the three groups were compared for microleakage using ANOVA, there was significant difference among the groups.

Conclusions:

To evaluate the dye penetration of microleakage, the FRC showed a better marginal adaptability for veneer restoration. Therefore, within the limitation of this study, the use of FRC as veneer on anterior teeth can be suggested.

Effect of immediate and delayed dentin sealing on the fracture strength, failure type and Weilbull characteristics of lithiumdisilicate laminate veneers

OBJECTIVES

Adhesion on dentin is less reliable than on enamel, which could affect the durability of laminate veneers (LV). Immediate dentin sealing (IDS) is suggested instead of delayed dentin sealing (DDS) to overcome hypersensitivity and prevent debonding from dentin. This study evaluated the effect of IDS and DDS on the durability of Li2Si2O5 laminate veneers in vitro.

METHODS

Window preparations were made on the labial surfaces of sound maxillary central incisors (N=50). They were randomly divided into five groups: Group 1: Enamel only+H3PO4+Adhesive (control); Group 2: <1/4 dentin+H3PO4+DDS (2 weeks later); Group 3: Complete dentin+H3PO4+DDS (2 weeks later); Group 4: <1/4 dentin+H3PO4+IDS; Group 5: Complete dentin+H3PO4+IDS. Li2Si2O5 laminate veneers (e.max Press) were bonded to the labial surfaces of the teeth with adhesive resin cement (Variolink Veneer). IDS layers were silicacoated (CoJet System) and silanized (ESPE-Sil). The teeth with their bonded laminates were thermocycled (10.000× cycles) and then subjected to static loading (1mm/min). Failure type and location after debonding were classified. Data were analyzed using ANOVA and Tukey's post hoc test (α=0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m) and shape (0), values were calculated.

RESULTS

Mean fracture strength (N) per group in descending order was as follows: Group 5 (576±254), Group 4 (478±216), Group 1 (473±159), Group 2 (465±186), and Group 3 (314±137). The presence of complete dentin exposure sealed with DDS after 2 weeks on the bonded surface (Group 3) resulted in significantly lower fracture strength results than those in group 5 with IDS (p=0.034). Weibull distribution presented higher shape (0) for Group 1 (3.67), than those of other groups (2.51-2.89). Failure types were predominantly adhesive failure between the cement and the laminate veneer in Groups 1, 2, 4 whereas Group 3 presented more often complete adhesive failures between the cement and dentin. In Group 5, failures showed some IDS and cement with or without ceramic fracture attached on the tooth.

SIGNIFICANCE

When laminate veneers are bonded to a large dentin substrate, application of immediate dentin sealing improves adhesion and thereby, the fracture strength of Li2Si2O5 laminate veneers.

In vitro evaluation of the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with composite fillings after cyclic loading

PURPOSE

There is insufficient data regarding the durability of porcelain laminate veneers bonded to existing composite fillings. The aim of the present study was to evaluate the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with existing composite fillings.

MATERIALS AND METHODS

Thirty maxillary central incisors were divided into three groups (for each group, n=10): intact teeth (NP), teeth with class III composite fillings (C3) and teeth with class IV cavities (C4). Porcelain laminate veneers were made using IPS-Empress ceramic and bonded with Panavia F2 resin cement. The microleakage of all of the specimens was tested before and after cyclic loading (1 × 10⁶ cycles, 1.2 Hz). The fracture resistance values (N) were measured using a universal testing machine, and the mode of failure was also examined. The statistical analyses were performed using one-way ANOVA and Tukey post hoc tests (α=.05).

RESULTS

There was a significant difference in the mean microleakage of group C4 compared with group NT (P=.013). There was no significant difference in the fracture loads among the groups.

CONCLUSION

The microleakage and failure loads of porcelain laminate veneers bonded to intact teeth and teeth with standard class III composite fillings were not significantly different.

Esthetic rehabilitation of anterior teeth with laminates composite veneers

No- or minimal-preparation veneers associated with enamel preservation offer predictable results in esthetic dentistry; indirect additive anterior composite restorations represent a quick, minimally invasive, inexpensive, and repairable option for a smile enhancement treatment plan. Current laboratory techniques associated with a strict clinical protocol satisfy patients' restorative and esthetic needs. The case report presented describes minimal invasive treatment of four upper incisors with laminate nanohybrid resin composite veneers. A step-by-step protocol is proposed for diagnostic evaluation, mock-up fabrication and trial, teeth preparation and impression, and adhesive cementation. The resolution of initial esthetic issues, patient satisfaction, and nice integration of indirect restorations confirmed the success of this anterior dentition rehabilitation.