Clinical outcomes and influence of material parameters on the behavior and survival rate of thin and ultrathin occlusal veneers: A systematic review

Achieving excellence with interdisciplinary approaches in complex orthodontic adult patients

Over the last decades the percentage of adult orthodontic patients has substantially increased. Undeniably, an important motif for seeking orthodontic care at an older age is smile improvement, but this is not all. Frequently, impaired dentofacial aesthetics are combined with several other issues: severe dentoskeletal malocclusions; multiple tooth loss due to caries or endodontic failure; dental agenesis or trauma; periodontal breakdown; or functional problems, such as temporomandibular disorders or obstructive sleep apnoea. Therefore, comprehensive adult treatment mostly requires close collaboration of a team of equally well-trained dental specialists to select and execute the most suitable treatment option for the individual patient from day one. With joint planning, intensive communication with the patient and the involved specialists, and continuous monitoring of the treatment process, true patient-centred care can be delivered. In order to serve the individual patient best, the treating orthodontist does not only need thorough speciality training and continuing education, but furthermore, should be well-equipped with sufficient knowledge of the other dental fields of expertise. In combination with digital technology as an important tool for enhancing communication and efficient exchange of information between all involved team members, excellent joint clinical skills will take comprehensive interdisciplinary treatment to the next level.

Survival rate, bond, and fracture strength of laminate veneers bonded to different tooth substrates: A systematic review of in vitro studies

PURPOSE

This study aimed to evaluate how different tooth substrates affect the survival rate, shear bond strength, fracture strength, and mode of failure of laminate veneers (LVs).

METHODS

This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In vitro studies comparing the bonding of laminate veneers to different substrates were included. Electronic databases and manual searches were performed to identify relevant studies. Data on survival rate, shear bond strength, fracture strength, and failure modes were extracted and analyzed using Review Manager software.

RESULTS

A total of 10 studies were included in the review, comprising 621 laminate veneers. The findings revealed that laminate veneers bonded to enamel substrate had lower failure rates than those bonded to tooth substrate with severely exposed dentin or existing composite restorations (ECRs). The failure modes observed were debonding, chipping, cracks, or fractures.

CONCLUSIONS

Bonding laminate veneers to enamel substrate showed higher survival rates compared to bonding to tooth substrates with severely exposed dentin or ECRs, underscoring the significance of enamel preservation. When dealing with exposed dentine surfaces or ECRs, it is crucial to perform appropriate surface treatment before luting to improve adhesion. This involves immediate dentine sealing, as well as the use of suitable primers and bonding agents.

The physical-mechanical properties of 3D-printed versus conventional milled zirconia for dental clinical applications: A systematic review with meta-analysis

AIM OF STUDY

This systematic review aimed to compare the physical-mechanical properties of 3D-printed (additively manufactured (AM)) zirconia compared to conventionally milled (subtractive manufactured: SM) zirconia specimens.

MATERIALS AND METHODS

A thorough search of Internet databases was conducted up to September 2023. The search retrieved studies that evaluated AM zirconia specimens and restorations regarding the physical-mechanical properties and mechanical behavior of zirconia. The main topic focused on 3Y-TZP. However, records of 4YSZ and 5YSZ were also included to gather more comprehensive evidence on additively manufactured zirconia ceramic. The quality of studies was assessed using the ROB2 tool, Newcastle Ottawa scale, and the Modified Consort Statement. Of 1736 records, 57 were assessed for eligibility, and 38 records were included in this review, only two clinical trials meet the inclusion criteria and 36 records were laboratory studies. There were no signs of mechanical complications and wear to antagonists with short-term clinical observation. SM thin specimens ≤1.5 mm showed statistically significant higher flexural strength than AM zirconia (p ≤ 0.01), while thicker specimens showed comparable outcomes (p > 0.5). The fracture resistance of dental restorations was dependent on the aging protocol, restoration type, and thickness. The bond strength of veneering ceramic to zirconia core was comparable.

CONCLUSIONS

The results pooled from two short-term clinical trials showed no signs of mechanical or biological complications of additively manufactured 3Y-TZP zirconia crowns. The flexural strength might depend on the specimens' thickness, but it showed promising results to be used in clinical applications, taking into account the printing technique and orientation, material composition (yttria content), solid loading, and sintering parameters. 3D-printed restorations fracture resistance improved when adhered to human teeth. The veneering ceramic bond was comparable to milled zirconia specimens. Long-term RCTs are recommended to confirm the mechanical behavior of 3D-printed restorations.

3D-printed intracoronal restorations, occlusal and laminate veneers: Clinical relevance, properties, and behavior compared to milled restorations; a systematic review and meta-analysis

OBJECTIVES

To assess the feasibility of producing 3D-printed intracoronal restorations, thin and ultrathin veneers, and to compare their mechanical behavior, accuracy, biological, and stain susceptibility to the currently applied milled restorations.

MATERIALS AND METHODS

The databases were comprehensively searched for relevant records up to January 2024 without language restrictions. All studies that assessed 3D-printed partial coverage restorations including inlays, onlays, laminate, and occlusal veneers were retrieved.

RESULTS

The web search yielded a total of 1142 records, with 8 additional records added from websites at a later stage. Only 17 records were ultimately included in the review. The included records compared 3D-printed; alumina-based- and zirconia ceramics, lithium disilicate ceramics, polymer infiltrated ceramics, polyetheretherketone (PEEK), resin composites, and acrylic resins to their CNC milled analogs. The pooled data indicated that it is possible to produce ultrathin restorations with a thickness of less than 0.2 mm. 3D-printed laminate veneers and intracoronal restorations exhibited superior trueness, as well as better marginal and internal fit compared to milled restorations (p < 0.05). However, it should be noted that the choice of materials and preparation design may influence these outcomes. In terms of cost, the initial investment and production expenses associated with 3D printing were significantly lower than those of CNC milling technology. Additionally, 3D printing was also shown to be more time-efficient.

CONCLUSIONS

Using additive manufacturing technology to produce restorations with a thickness ranging from 0.1 to 0.2 mm is indeed feasible. The high accuracy of these restorations, contributes to their ability to resist caries progression, surpassing the minimum clinical threshold load of failure by a significant margin and reliable adhesion. However, before 3D-printed resin restorations can be widely adopted for clinical applications, further improvements are needed, particularly in terms of reducing their susceptibility to stains.

CLINICAL SIGNIFICANCE

3D-printed intracoronal restorations and veneers are more time and cost-efficient, more accurate, and could provide a considerable alternative to the currently applied CNC milling. Some limitations still accompany the resin materials, but this could be overcome by further development of the materials and printing technology.

3D-printed versus conventionally milled zirconia for dental clinical applications: Trueness, precision, accuracy, biological and esthetic aspects

OBJECTIVES

This systematic review aimed to compare the clinical outcome, internal gap, trueness, precision, and biocompatibility of 3D-printed (AM) compared to milled (SM) zirconia restorations.

DATA SOURCE

A thorough search of Internet databases was conducted up to September 2023. The search retrieved studies compared AM zirconia to SM zirconia restorations regarding clinical outcome, fit, trueness, precision, and biocompatibility.

STUDY SELECTION

Of 1736 records, only 59 were screened for eligibility, and 22 records were included in this review. The quality of studies was assessed using the revised Cochrane risk-of-bias tool (ROB2), and the Modified Consort Statement. One clinical study exhibited a low risk of bias. All laboratory studies revealed some bias concerns. Short-term observation showed 100 % survival with no signs of periodontal complications. 3D-printed zirconia crowns showed statistically significant lower ΔE and a better match to adjacent teeth (p ≤ 0.5). The fit, trueness, and precision vary with the printing technique and the tooth surface.

CONCLUSIONS

3D-printed zirconia crowns provide better aesthetic color and contour match to adjacent natural teeth than milled crowns. Both 3D printing and milling result in crowns within the clinically acceptable internal and marginal fit. Except for nanoparticle jetting, the marginal gap of SM crowns was smaller than AM crowns, however, both were clinically acceptable. Laminate veneers might be more accurately produced by 3D printing. 3D-printed axial surface trueness was better than milled axial surfaces. Long-term RCTs are recommended to confirm the clinical applicability of 3D-printed restorations.

CLINICAL SIGNIFICANCE

Internal fit and gap, precision, and trueness are fundamental requirements for successful dental restorations. Both techniques produce restorations with clinically acceptable marginal and internal fit. Axial surfaces and narrow or constricted areas favored 3D-printed than conventionally milled zirconia.

Clinical outcomes of self-glazed zirconia veneers produced by 3D gel deposition: a retrospective study

BACKGROUND

Self-glazed zirconia (SZ) restorations are made by a novel additive three-dimensional gel deposition approach, which are suitable for a straightforward completely digital workflow. SZ has recently been used as minimally invasive veneer, but its clinical outcomes have not been clarified yet. This study aimed to evaluate the preliminary clinical outcomes of SZ veneers compared with the widely used lithium disilicate glass-ceramic veneers made by either pressing (PG) or milling (MG) process.

METHODS

Fifty-six patients treated with SZ, PG, and MG veneers by 2 specialists between June 2018 and October 2022 were identified. Patients were recalled for follow-up at least 1 year after restoration. Clinical outcomes were assessed by 2 independent evaluators according to the modified United States Public Health Service (USPHS) criteria. Overall patient satisfaction was assessed using visual analogue scale (VAS), and analyzed by one-way ANOVA. Chi-square test was applied to compare the difference in the success and survival rates among the 3 groups.

RESULTS

A total of 51 patients restored with 45 SZ, 40 PG, and 41 MG veneers completed the study, with a patient dropout rate of 8.9%. Mean and standard deviation of follow-up period was 35.0 ± 14.7 months. All restorations performed well at baseline, except for 2 SZ veneers with mismatched color (rated Bravo). During follow-up, marginal discrepancy (rated Bravo) was found in 4 MG veneers and 1 PG veneer, and partially fractured (rated Charlie) was found in another 2 PG veneers. The survival rate of SZ, PG, and MG veneers was 100%, 95%, and 100%, with a success rate of 95.56%, 92.50%, and 90.24%, respectively, none of which were significantly different (p = 0.099 and 0.628, respectively). The mean VAS score of SZ, PG, and MG was 95.00 ± 1.57, 93.93 ± 2.40, and 94.89 ± 2.00 respectively, without significant difference (p > 0.05).

CONCLUSION

SZ veneers exhibited comparable preliminary clinical outcomes to PG and MG veneers, which could be considered as a feasible option for minimally invasive restorative treatment.

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.

Criteria for choosing prosthetic biomaterials according to their physicochemical properties for anterior and posterior sectors. a comprehensive review

Objective

To describe the existing knowledge about metal-free prosthetic biomaterials according to their physicochemical properties and based on this, define criteria for their placement in both the anterior and posterior sectors.

Materials and methods

A digital search was carried out in the databases: PubMed/Medline, Scopus, Web of Science and Google Scholar of the literature published in the English language without time restrictions and included original articles such as case reports, retrospective and prospective studies, narrative, comprehensive, systematic reviews and meta-analysis. Meanwhile, short communications, editorials and articles in a language other than English were excluded.

Results

40 articles were evaluated, published between 2000 and 2023. The main characteristics and physicochemical properties of ceramic biomaterials such as zirconia, feldspathic based ceramics, lithium disilicate and alumina, among others, were analyzed and summarized. In addition, certain criteria were defined based on the available scientific evidence on the use of different ceramic systems both in the anterior sector and in the posterior sector for patients who need some type of prosthetic restoration.

Conclusions

Among the different metal-free materials used for the construction of fixed dental prostheses, zirconia has been shown to have better aesthetic, biomechanical and biocompatibility properties, which makes it a candidate material for the rehabilitation of partially edentulous patients.

Minimally invasive CAD/CAM lithium disilicate partial-coverage restorations show superior in-vitro fatigue performance than single crowns

OBJECTIVE

To analyze the influence of restoration design (partial-coverage restoration vs. crown) and ceramic layer thickness on the performance and failure loads of CAD/CAM-fabricated lithium disilicate (LDS) reconstructions on molars after fatigue.

MATERIALS AND METHODS

Seventy-two posterior monolithic CAD/CAM-fabricated LDS restorations (IPS e.max CAD, Ivoclar Vivadent) with different occlusal/buccal ceramic layer thicknesses (1.5/0.8, 1.0/0.6, and 0.5/0.4 mm) and restoration designs (PCR: non-retentive full-veneer/partial-coverage restoration, C: crown,) were investigated and divided into six groups (n = 12, test: PCR-1.5, PCR-1.0, PCR-0.5; control: C-1.5, C-1.0, C-0.5). LDS restorations were adhesively bonded (Variolink Esthetic DC, Ivoclar Vivadent) to dentin-analogue composite dies (Z100, 3M ESPE). All specimens were subjected to thermomechanical loading (1.2 million cycles, 49 N, 1.6 Hz, 5-55°C) and exposed to single load to failure testing. Failure analysis was performed with light and scanning electron microscopies. Data were statistically analyzed using ANOVA, Tukey-Test, and t-test (p < 0.05).

RESULTS

Eight crown samples (C-0.5) and one PCR specimen (PCR-0.5) revealed cracks after fatigue, resulting in an overall success rate of 87.5% (crowns: 75%, PCRs: 96.88%). Direct comparisons of PCRs versus crowns for thicknesses of 0.5 mm (p < 0.001) and 1.0 mm (p = 0.004) were significant and in favor of PCRs. Minimally invasive PCRs (0.5 and 1.0 mm) outperformed crowns with the identical ceramic thickness. No difference was detected (p = 0.276) between thickness 1.5 mm PCRs and crowns.

CONCLUSIONS

Minimally invasive monolithic CAD/CAM-fabricated posterior LDS PCRs (0.5 and 1.0 mm) resulted in superior failure load values compared to minimally invasive crowns. Minimally invasive crowns (0.5 mm) are prone to cracks after fatigue.

CLINICAL SIGNIFICANCE

Minimally invasive CAD/CAM-fabricated LDS PCR restorations with a non-retentive preparation design should be considered over single crowns for molar rehabilitation.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2022 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertise in their subject areas that include (in order of the appearance in this report): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence the daily dental treatment decisions of the reader with an emphasis on innovations, new materials and processes, and future trends in dentistry. With the tremendous volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope that readers find this work helpful in managing patients.

Conventional Versus Minimally Invasive Veneers: A Systematic Review

This systematic review aimed to synthesize and analyze a collection of studies focused on comparing conventional veneers (CVs) and minimal or no-preparation veneers (MPVs) within the domain of prosthodontics. The review sought to explore various attributes, techniques, outcomes, and considerations associated with these two approaches. The key aspects investigated included esthetics, longevity, periodontal health, patient satisfaction, structural influences such as microleakage and marginal fit, cement thickness, and color stability. A systematic literature search was conducted to identify relevant studies published up to the present date. Studies meeting specific inclusion and exclusion criteria were selected for review. Studies pertaining to various methodologies were identified initially as part of the strategy and bias assessment was performed to determine the credibility of their assessments before inclusion in this review. Four comparative assessments gleaned from the selected studies provided a comprehensive overview of the strengths and limitations associated with CVs and MPVs. MPVs demonstrated advantages such as enhanced survival rates and extended mean success periods, implying their potential as viable long-term restorative options. Meticulous patient management and optimal preparation techniques emerged as crucial factors influencing successful outcomes. Structural attributes, including microleakage and marginal fit, varied depending on the preparation techniques employed. Moreover, considerations related to color changes in veneers underscored the intricate interplay between material properties and fabrication methods. The insights underscore the significance of patient-centric care, precision preparation methodologies, and material choices in guiding successful outcomes. However, the diverse methodologies and constraints of certain studies warrant careful interpretation. This study accentuates the potential for future research directions, interdisciplinary collaboration, and the advancement of evidence-based practices within veneer dentistry.

Fatigue behavior, failure mode, and stress distribution of occlusal veneers: influence of the prosthetic preparation cusp inclinations and the type of restorative material

OBJECTIVE

To evaluate the effects of cusp inclination of the prosthetic preparation's occlusal surface and type of restorative material on the fatigue behavior, failure mode, and stress distribution of occlusal veneers.

MATERIALS AND METHODS

Glass fiber-reinforced epoxy resin prosthetic preparations for occlusal veneers with three different occlusal surface cusp inclination degrees (0°, 15°, and 30°) were produced and assigned into six testing groups (n = 11) according to the cusp inclination (0°, 15°, or 30°) and type of restorative material (lithium disilicate-LD or resin composite-RC). Despite different substrate preparation cusp inclination degrees, the restorations were designed maintaining 30° inclination between the cusps at the occlusal surface and a thickness of 0.7 mm at the central groove region of the restorations to be machined in a CAD/CAM system. After cementation, the specimens were stored for about 7 days (under water at 37 °C), and subsequently submitted to a load to failure test (n = 2) and an intermittent cyclic fatigue test (n = 9) (initial load: 100 N; step size: 50 N; cycles/step: 10,000; loading frequency: 20 Hz; loading piston: 6-mm-diameter stainless steel) until observing cracks. The data were analyzed by two-way ANOVA, Kaplan-Meier, and Mantel-Cox post hoc tests. Finite element analysis (FEA) and fractographic analyses were performed.

RESULTS

The fatigue performance of LD and RC occlusal veneers was evaluated based on different prosthetic preparation cusp inclinations. The 0° inclination showed the best fatigue performance for both materials (LD: 944N, RC: 861N), while the 15° and 30° inclinations had lower values (LD: 800N and 533N, RC: 739N and 717N, respectively). The study also found that for a 0° inclination, LD occlusal veneers performed better than RC ones (LD: 944 N > RC: 861N), while for a 30° inclination, RC occlusal veneers had better fatigue performance than LD ones (LD: 533N < RC: 717N). No significant difference was observed between the materials for a 15° inclination (LD: 800N = RC: 739N). The FEA results showed a higher tensile stress concentration on lithium disilicate than on resin composite occlusal veneers. All lithium disilicate occlusal veneers showed radial crack failures, while resin composite occlusal veneers showed Hertzian cone cracks and radial cracks combined.

CONCLUSION

Considering mechanical perspective only, RC occlusal veneers should be indicated when prosthetic preparation cusps inclinations are 30°. When 0° prosthetic preparation cusps inclinations are observed, LD occlusal veneers will behave mechanically better. When a 15° cusp inclination is preserved, both restorative materials behave similarly.

Fracture load and failure mode of semi-direct resin composite occlusal veneers: Influence of design and mechanical cycling

AIMS

To evaluate the influence of the type of preparation and mechanical cycling on the fracture load and failure mode of semi-direct posterior resin composite restorations.

METHODS

In total, 70 healthy third molars were used; 10 belonging to the control group (C - unprepared teeth) and 60 teeth prepared and restored with nanoparticle resin composite, divided into 3 groups (n = 20): O - exclusively occlusal preparation (Table Top); OV - occlusal preparation with buccal extension (Veneerlay); OVP - Occlusal preparation with chamfer on the proximal and buccal-lingual/palatal surfaces (Overlay). The preparations were performed with diamond burs with a thickness of 1 mm. The restorations were made with nanoparticulate resin composite (Filtek Z350 XT) and subsequently received additional polymerization (thermoprocessing). Cementation was performed with the use of universal adhesive system (Single Bond Universal) on dental substrate and dual resin cement (RelyX ARC). Half of the teeth in each group (n = 10) were submitted to mechanical cycling, simulating 6 months of clinical service (5 × 105 fatigue cycles), under dynamic loading of 130 N, at a frequency of 2Hz. Fracture load tests were performed in a universal testing machine with a 200 kgf load cell. Failure mode was classified using scores. Generalized linear models and Fisher Exact tests were applied to the data (significance level of 5%).

RESULTS

There were no significant differences between the types of preparation (p = 0.9435), or relative to cycling (p = 0.3764). The Fisher Exact Test showed a significant association between the groups and the type of failure (p = 0.0006), with preparations O (with cycling) and OVP (with and without cycling) exhibiting most failures with restoration fractures without involvement of the dental remnant.

CONCLUSIONS

Semi-direct restorations showed resistance to fracture load similar to that of healthy teeth and were capable of withstanding functional masticatory loads. The type of preparation influenced the failure mode of teeth. The Table Top and Overlay types of preparations were those had fewer catastrophic failures, suggesting that since they are more conservative preparations, they made it possible for the tooth to receive a new restorative procedure in the future in cases of failures.

Effect of preparation design on marginal adaptation and fracture strength of ceramic occlusal veneers: A systematic review

OBJECTIVES

This systematic review aims to investigate the effect of different preparation designs on the marginal fit and fracture strength of ceramic occlusal veneers.

MATERIALS AND METHODS

Based on the PICO question and the search terms, an electronic search was performed in Google Scholar, PubMed (MEDLINE), Scopus, Cochrane Library, Web of Science, Science Direct, Wiley, Ovid, and SAGE for articles published up to July 2022. After including English in vitro studies that evaluated posterior ceramic occlusal overlays at the posterior with ceramic restorations by following the PRISMA statement, the extracted data was tabulated. The methodological quality of the included studies was evaluated. Risk of bias assessment was done independently by two authors using the modified MINORS scale.

RESULTS

About 3138 search results were screened, of which 22 were selected due to their titles. Twenty-one full-text articles were assessed for eligibility. Seventeen in-vitro studies were finalized for the extraction of quantitative data. All 17 articles had a low risk of bias and were retained. The influencing items for evaluating the research were different in most studies; therefore, qualitative synthesis of the results was feasible. They generally included preparation design, material thickness, depth of preparation in the tooth, internal divergence angle, and finish line. Meta-analysis was not done due to heterogeneity of preparation types and evaluation methods. Results revealed that fracture resistance of occlusal veneers is higher than normal mastication force, and it is sufficient to prepare the occlusal surface, use a self-etching primer for bonding, and an acceptable minimum ceramic thickness. The marginal discrepancy of occlusal veneers is clinically acceptable. However, this systematic review faces some limitations due to the lack of in vivo studies, different preparation designs in included studies, different follow-ups, and lack of comprehensive explanations in articles.

CONCLUSIONS

The preparation design of occlusal veneers influences both marginal adaptation and fracture resistance. Various preparation designs are proven to have clinically acceptable fracture strength and marginal adaptation.