Dental and Medical Problems

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Dental and Medical Problems

2024, vol. 61, nr 3, May-June, p. 417–426

doi: 10.17219/dmp/157347

Publication type: review

Language: English

License: Creative Commons Attribution 3.0 Unported (CC BY 3.0)

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Del Cisne Maldonado K, Espinoza JA, Astudillo DA, Delgado BA, Bravo WD. Resistance of CAD/CAM composite resin and ceramic occlusal veneers to fatigue and fracture in worn posterior teeth: A systematic review. Dent Med Probl. 2024;61(3):417–426. doi:10.17219/dmp/157347

Resistance of CAD/CAM composite resin and ceramic occlusal veneers to fatigue and fracture in worn posterior teeth: A systematic review

Karelys Del Cisne Maldonado1,A,B,C,D, Juan Andres Espinoza1,2,A,B,C,D,E, Daniela Andrea Astudillo3,A,B,C,F, Bolivar Andres Delgado4,A,B,C,F, Wilson Daniel Bravo3,A,B,C,F

1 Graduate Program in Oral Rehabilitation and Implant-Assisted Prosthesis, University of Cuenca, Ecuador

2 Investigation Department, University of Cuenca, Ecuador

3 Graduate Department of Oral Rehabilitation and Implant-Assisted Prosthesis, University of Cuenca, Ecuador

4 Department of Prosthodontics, Catholic University of Cuenca, Ecuador

Abstract

Severe tooth wear is related to substantial loss of tooth structure, with dentin exposure and significant loss (≥1/3) of the clinical crown. The objective of this systematic review was to summarize and analyze the scientific evidence regarding the mechanical performance of computer-aided design/computer-aided manufacturing (CAD/CAM) composite resin and CAD/CAM lithium disilicate ceramic occlusal veneers, in terms of fatigue and fracture resistance, on severely worn posterior teeth. Currently, occlusal veneers are an alternative for treating worn posterior teeth. Although scientific evidence demonstrates the good performance of lithium disilicate occlusal veneers, there are less brittle materials with a modulus of elasticity more similar to dentin than ceramics, such as resin CAD/CAM blocks. Therefore, it is important to identify which type of material is best for restoring teeth with occlusal wear defects and which material can provide better clinical performance. This review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive search of the PubMed, Embase, Web of Science, Scopus, Cochrane, OpenGrey, Redalyc, DSpace, and Grey Literature Report databases was conducted and supplemented by a manual search, with no time or language limitations, until January 2022. We aimed to identify studies evaluating the fatigue and fracture resistance of CAD/CAM composite resin and ceramic occlusal veneers. The quality of the full-text articles was evaluated according to the modified Consolidated Standards of Reporting Trials (CONSORT) criteria for in vitro studies, and 400 articles were initially identified. After removing duplicates and applying the selection criteria, 6 studies were included in the review. The results demonstrated that the mechanical performance of CAD/CAM composite resin occlusal veneers is comparable to that of CAD/CAM lithium disilicate occlusal veneers in terms of fatigue and fracture resistance.

Keywords: tooth wear, ceramics, survival rate, composite resin, CAD/CAM

Introduction

In the first clinical study measuring tooth wear in young patients, the authors observed a mean annual occlusal enamel wear of 29 µm in molars and 15 µm in premolars.1 A 2015 report estimated that the mean height of the maxillary incisor crown at 10 years of age was 11.94 mm, and decreased to 10.93 mm in 70-year-old patients, corresponding to a loss of 1.01 mm (1,010 µm) in 60 years.2 The wear was greater in the mandibular incisors, with the mean crown height at 10 years of age being 9.58 mm, which decreased to 8.12 mm in patients aged 70 years old, resulting in a loss of 1.46 mm (1,460 µm) over the course of 60 years. These values correspond to a physiological annual wear rate of 16.8 µm for the maxillary incisors and 24.3 µm for the mandibular incisors.2

It is important to differentiate between severe tooth wear and pathological tooth wear. The latter refers to atypical tooth wear for the patient’s age that causes pain or discomfort, functional problems, or deterioration of the aesthetic appearance which, if progresses, can lead to undesirable complications of increasing complexity.2 Severe tooth wear is related to substantial loss of tooth structure, with dentin exposure and significant loss (≥1/3) of the clinical crown.3 However, not all cases of severe tooth wear can be considered pathological, especially among elderly people. According to an epidemiological study conducted in 2015, the estimated prevalence of erosive tooth wear in children and adolescents was 30.4%.4 The most recent European consensus on the management of severe tooth wear3 recommends the use of indices such as the Basic Erosive Wear Examination (BEWE)5 and the Tooth Wear Evaluation System (TWES)6 for diagnosis. Severe tooth wear can be attributed to a number of factors, including excessive consumption of carbonated beverages, a high-acid diet, gastric diseases, anorexia, bulimia, teeth grinding, and the use of highly abrasive pastes.7, 8, 9, 10, 11, 12 These factors can affect the patient in several ways, including the loss of vertical dimension, sensitivity due to dentin exposure, poor aesthetics, and neuromuscular disorders.7, 11, 12

Restorative alternatives have been sought to solve these problems, such as the placement of metal-free crowns. Although this technique has shown a high survival rate (92% at 5 years and 85.5% at 10 years),13 it requires mechanical retention, necessitating the removal of more dental tissue, including healthy tissue. Advances in dental materials and adhesive techniques have led to a reduction in the indications for crowns.14, 15 Occlusal veneers have emerged as a viable alternative for the treatment of posterior tooth wear, as they require minimal tooth preparation, ranging from 0.4 mm to 0.6 mm at the level of the developmental groove and from 1 mm to 1.3 mm at the tip of the cusp, largely preserving healthy dental tissue. Due to the bonding characteristics of these materials and the more intuitive preparation guided by anatomical considerations, there are instances where no dental tissue is removed.16, 17, 18

Advances in computer-aided design/computer-aided manufacturing (CAD/CAM) technology and bonding procedures (immediate dentin sealing)19, 20 have enabled the fabrication of thin occlusal veneers without compromising their performance.16 Scientific evidence indicates that lithium disilicate occlusal veneers exhibit excellent performance.21, 22 However, less brittle materials with a modulus of elasticity comparable to that of dentin, such as composite resin, are also available.17, 19, 23 A number of  studies, the majority of which were conducted in a laboratory setting, have evaluated the mechanical properties of occlusal veneers using universal test machines and mastication simulators under physiological and/or pathological occlusal loading conditions.19, 23, 24, 25 However, there is no up-to-date systematic review that allows the clinician to make an informed decision regarding the most appropriate material for restoring teeth with occlusal wear. Therefore, the objective of this systematic review is to analyze and summarize the scientific evidence evaluating the mechanical performance of CAD/CAM composite resin and lithium disilicate ceramic occlusal veneers in severely worn posterior teeth, with a particular focus on the fatigue and fracture resistance.

Material and methods

Registration protocol

This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.26 Additionally, the review was registered in the International Platform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) (doi:10.37766/inplasy2021.10.0036; https://inplasy.com/inplasy-2021-10-0036).

Search strategy

The purpose of the search was to address the following question: in posterior teeth with severe tooth wear, can occlusal veneers made from CAD/CAM composite resin blocks perform better mechanically in terms of fatigue and fracture resistance compared to CAD/CAM lithium disilicate occlusal veneers? The research question was developed in accordance with the Population, Intervention, Comparison, and Outcome (PICO) framework.

Three independent researchers (KM, JE and DA) con­ducted an exhaustive electronic search of the following databases: PubMed, Scopus, Cochrane, Embase, and Web of Science, to identify relevant articles published before January 2022. The Medical Subject Headings (MeSH), Embase subject headings (Emtree) and free terms were used without restrictions in terms of language and year of publication. A search strategy is presented in the supplementary materials (available on request from the corresponding author). To identify other potentially rele­vant articles, 2 researchers (KM and JE) conductedmanual search of the bibliographic citations of the included articles and the following journals: Dental Materials; Journal of Dental Restoration; Journal of Dentistry; Journal of Oral Rehabilitation; Journal of Esthetic and Restorative Dentistry; Dental Materials Journal; Journal of Material Sciences. The search for grey literature was performed by KM and JE in the OpenGrey, Redalyc, DSpace, and Grey Literature Report databases.

Eligibility criteria

The present systematic review included studies on the indirect restoration of worn posterior teeth with machined materials. The studies compared the mechanical properties of CAD/CAM composite resin and ceramic materials, including the fatigue and fracture resistance. This review included randomized controlled trials, non-randomized controlled trials and in vitro studies.

Studies investigating CAD/CAM restorations on endodontically treated teeth, as well as crown, inlay, onlay, and implant restorations, case reports, literature reviews, expert opinions, and systematic reviews were excluded.

Screening and selection

Two researchers (KM and JE) independently selected the studies for inclusion based on their titles and abstracts. If a decision regarding inclusion could not be made because of insufficient data in the title and abstract, the complete manuscript was obtained for further analysis. The articles in which both researchers concurred were selected. The articles selected for full-text reading were evaluated independently by 2 researchers (KM and JE). Any disagree­ment regarding the eligibility of the included studies was resolved through discussion and consensus, or by a third reviewer (DA). Only papers that met all the eligibility cri­teria were included.

The modified Consolidated Standards of Reporting Trials (CONSORT) tool27 was employed to assess the methodological quality of the articles included in the study in terms of their correct implementation and the structure of the abstract, introduction, methods, results, discussion, and funding.

Data extraction

A data extraction protocol was defined and evaluated by 2 authors (KM and JE). The data was extracted independently from the full-text articles using a standardized form in electronic format (Microsoft Excel 2016; Microsoft Corporation, Redmond, USA). The information was classified according to the authors, year of the study, study design, type of material, sample size, objectives, testing machine used, and conclusions (Table 1).

Risk of bias assessment

Two authors (KM and JE) independently evaluated the risk of bias in the studies included in this review based on a previous study.28 The following parameters were assessed: tooth randomization, the use of teeth free of caries or restorations, the use of materials following manufac­turers’ instructions, the use of teeth with similar dimensions, tooth preparation by the same operator, the description of sample size calculations, and blinding of the testing machine operator. If the author reported the para­meter, the article received a “yes” (Y) for that specific para­meter; if the information was not found, the article received a “no” (N). Articles reporting 1 to 3 items were classified as exhibiting a high risk of bias, 4 or 5 items as a medium risk of bias, and 6 or 7 items as a low risk of bias. Any disagreements regarding the risk of bias were resolved through consensus. If a consensus could not be reached, the third author (DA) intervened.

Results

Selection of studies

A PRISMA flowchart, which provides a summary of the selection process, is presented in Figure 1. A total of 400 studies were identified through the search process, with 25 duplicate records being removed. Another 4 studies were removed because they were book chapters, and 352 studies were excluded as they did not meet the eligibility criteria. The remaining 19 studies were subjected to a full-text review. Three studies were excluded because they employed finite element analyses, 1 study was a systematic review, and 9 studies did not meet the inclusion criteria. Therefore, a total of 6 studies were included in the systematic review. Three of these examined the fracture resistance,23, 25, 29 while the remaining 3 examined the fatigue resistance.17, 19, 30

Risk of bias

Of the 6 included studies, 2 were identified as having a medium risk of bias,23, 25 while 4 had a high risk of bias.17, 19, 29, 30 The results are described in Table 2, according to the parameters considered in the analysis. The most commonly identified risks of bias among the studies were a lack of blinding of the testing machine operator, a lack of description of the sample size calculation, and tooth preparation performed by the same operator.

Main findings

The characteristics of the materials used in the studies included in this systematic review are presented in Table 3. The fracture resistance of CAD/CAM occlusal veneers was evaluated in 3 studies.23, 25, 29 Two of these studies had restorations of the same thickness and used thermo­cycling.25, 29 The results indicate that there is no statistically significant difference between the use of CAD/CAM composite occlusal veneers and CAD/CAM lithium di­silicate veneers (Table 4).

On the other hand, the fatigue resistance was evaluated according to the survival rate in 3 investigations,17, 19, 30 with 1 study demonstrating no statistically significant difference in the survival rate.30 However, in 2 studies, the survival rate was higher in CAD/CAM composite resin occlusal restorations (Table 5).

The results of this study indicate that the use of CAD/CAM composite and lithium disilicate occlusal veneers in worn posterior teeth is a viable option. Due to the heterogeneity and risk of bias, a quantitative analysis could not be performed.

Discussion

This systematic review demonstrates that CAD/CAM composite resin occlusal veneers exhibit fracture resistance values ranging from 1,018.5 N to 3,584.0 N, even in thin veneers (0.5–1.5 mm), which exceed the maximum bite force of patients without parafunctional habits (424–630 N).23 These results are consistent with those of a systematic review31 that recommends the use of CAD/CAM composite resin occlusal veneers less than 1-mm thick and lithium disilicate veneers from 0.7 mm to 1.5 mm thick. In their study, Maeder et al.32 evaluated various materials and found that VITA ENAMIC®, with a thickness of 0.5 mm, required a 800-N greater load than the maximum bite force to produce a crack in the veneer. Therefore, this material reaches high values of fracture resistance, which can be attributed to its composition, consisting of a hybrid structure with 2 inter­penetrated ceramic and polymeric networks, and resulting in a Weibull modulus of 20. This is in relation to the fracture range, reliability and strength of the material.33 Ioannidis et al.34 also reported that 0.5-mm thick VITA ENAMIC occlusal veneers have load capacity values above the normal force intervals. Johnson et al.16 compared CAD/CAM composite resin occlusal veneers, including Lava Ultimate and Paradigm MZ100 with varying thicknesses (0.3 mm, 0.6 mm and 1 mm). The obtained fracture resistance values were higher than normal masticatory forces, even at the minimum thickness of 0.3 mm. Therefore, minimum thickness, non-ceramic occlusal veneers could be considered a restorative option in patients with normal masticatory loads. However, in patients with parafunctional habits and excessive loads (780–1,120 N), complications may arise, including restoration dislodgment and fracture.16, 23

In terms of fatigue resistance, there were no statisti­cally significant differences between CAD/CAM lithium disilicate and composite resin occlusal veneers with a thickness of 0.3–0.5 mm, including IPS e.max CAD and Lava Ultimate, respectively. In the studies conducted by Magne et al.19 and Schlichting et al.,17 Paradigm MZ100 occlusal veneers with thicknesses of 1.2 mm and 0.6 mm demonstrated higher resistance values than IPS e.max CAD, applying a final load of 1,400 N in both studies. On the other hand, in the study by Schlichting et al.,17 XR experimental blocks were also significantly stronger than IPS e.max CAD, but not different from MZ100. The results of these studies suggest that higher flexural strength does not necessarily correspond to higher load resistance.19 According to the studies included in this systematic review, CAD/CAM composite resin occlusal veneers have a survival rate of 95–100%, despite their lower flexural strength than lithium disilicate veneers. For example, lithium disilicate has a flexural strength of 360–440 mPa, in contrast to MZ100, which has a flexural strength of 150 mPa.17, 19, 35 Neither of these values is correlated with the respective survival rate. Similarly, Lava Ultimate and VITA ENAMIC blocks show flexural strength values of 200 mPa and 150–160 mPa, respectively.23 The elastic moduli of Lava Ultimate (13 gPa) and VITA ENAMIC (30 gPa) are close to that of dentin (20.3 gPa), suggesting that they may influence the performance of restorations,23 since the elasticity of dentin compensates for the stiffness of enamel, cushioning it against masticatory forces. Consequently, the distribution of stress within a restored tooth during mastication depends on this property.36, 37 However, it should be noted that thermocycling was not employed in the studies conducted by Magne et al.19 and Schlichting et al.17

In vitro studies that use thermocycling are of great importance, as the procedure enables the simulation of the physiological conditions and temperature changes in the oral environment, which can result in physico­chemical alterations in dental materials.25, 32, 38 The study of Al-Akhali et al.29 evaluated restoration survival by subjecting specimens to thermocycling for 1,200,000 cycles, which simulates 5 years of clinical service.39, 40 The results indicated low survival rates for both VITA ENAMIC and IPS e.max CAD blocks (37.5% and 50%, respectively). However, the authors of the study posit that the self-etch protocol reduced the fracture resistance of the CAD/CAM composite resin and lithium disilicate ceramic blocks. Therefore, enamel etching is required when placing occlusal veneers, since the self-etch technique results in an insufficient and unstable bond between the veneer and the tooth.29 Self-etch adhesive systems produce a superficial enamel etching with reduced microporosity for resin infiltration, while orthophosphoric acid creates a porous enamel surface 5–50 μm deep. The poor etchability of self-etching adhesive systems on enamel can lead to pigmentation at the enamel margins, which may affect aesthetics, and could also be responsible for restoration dislodgement, marginal leakage and secondary caries, because self-etching does not achieve lasting adhesion to the enamel. Therefore, self-etching adhesive systems should be preceded by selective enamel etching with orthophosphoric acid.41, 42, 43, 44, 45

Occlusal veneers have been proposed as an alternative to full-coverage restorations for the treatment of worn posterior teeth, based on the results of several studies demonstrating their satisfactory mechanical properties.17, 21 Glass-ceramics, used in their manufacture, demonstrate several advantages, such as color stability, biocompatibility, durability, favorable translucency, chemical stability, reduction in the accumulation of bacterial plaque, and adequate marginal adjustment. However, they also have disadvantages, such as chipping, porosity and microstructural defects.30, 46, 47, 48, 49, 50 The CAD/CAM composite resin blocks are advantageous due to the low wear of the opposing teeth, a dentin-like elastic modulus, low cost, and the possibility of repair. Some disadvantages of this material include its tendency to absorb water, as well as its susceptibility to chemical and mechanical degradation.23, 51, 52

A comparative analysis of the fatigue and fracture resistance of CAD/CAM composite resin and CAD/CAM lithium disilicate blocks revealed that both materials, with a thickness ranging from 0.5 mm to 1.5 mm, are suitable for the treatment of occlusally worn teeth using an etch-and-rinse bonding procedure. However, these results should be interpreted with caution, as the present review revealed some limitations. The majority of the included studies showed a high risk of bias, as they did not clarify whether the extracted teeth were prepared by the same oper­ator, and only 1 study mentioned the sample size calcula­tion.25 Additionally, variables such as the number of cycles, the load applied and veneer thickness were not consistent across all the included studies. It should also be noted that no clinical trials were identified during the search, as all included studies were conducted in vitro. Therefore, simulating the oral environment is challenging. Nevertheless, only 2 studies25, 29 used thermocycling, and it has been suggested that clinical studies be conducted with long-term follow-up. It is therefore recommended that future studies adopt a standardized methodology. Although the studies included in this review compared CAD/CAM lithium disilicate blocks (IPS e.max CAD; Ivoclar Vivadent AG, Schaan, Liechtenstein) with CAD/CAM composite resin blocks (Lava Ultimate, 3M ESPE, St. Paul, USA; VITA ENAMIC®, VITA Zahnfabrik, Bad Säckingen, Germany; Paradigm MZ100 Block, 3M ESPE), it should be noted that there are more CAD/CAM composite resin materials, such as Grandio blocs (VOCO GmbH, Cuxhaven, Germany), with high filler content (86% w/w), a high elastic (18 gPa) and flexural (290 mPa) modulus, a fracture resistance of 2,500 N, and a bite force that exceeds that of patients with parafunction.53, 54 Another notable material is BRILLIANT Crios (Coltène AG, Altstätten, Switzerland), which has an elastic modulus of 10 gPa and a fracture resis­tance of 1,255 N at a thickness of 1 mm.50 However, to date, no studies have been conducted to compare occlusal veneers fabricated from these materials with lithium disili­cate veneers. Due to the wide heterogeneity of the included studies, a meta-analysis could not be performed.

Conclusions

Computer-aided design/computer-aided manufacturing composite resin occlusal veneers exhibit similar mechanical performance in terms of fatigue and fracture resistance to CAD/CAM lithium disilicate veneers. Both types of veneers are suitable for use on worn posterior teeth. The CAD/CAM composite resin occlusal veneers are economical and repairable, while CAD/CAM lithium disilicate occlusal veneers have better color stability and reduced plaque accumulation. The optimal thickness for CAD/CAM composite resin and lithium disilicate occlusal veneers is 0.5–1.5 mm. Additionally, an etch-and-rinse or self-etch adhesive system with selective etching of the surface of the dental substrate should be used. It is recommended that randomized clinical studies be conducted on this topic.

Ethics approval and consent to participate

Not applicable.

Data availability

The datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.

Consent for publication

Not applicable.

Tables


Table 1. Summary of the studies included in the systematic review

Study

Study design

Material

Sample size

Objectives

Testing machine

Conclusions

Andrade et al.
201823

in vitro

 IPS e.max CAD
 VITA ENAMIC®
 Lava™ Ultimate

70 human third molars

To evaluate, in vitro, the influence of CAD/CAM restorative materials and their thickness (0.6 mm and 1.5 mm) on the fracture resistance of teeth restored with occlusal veneers.

 cyclic mechanical loading: ER-11000 (ERIOS, São Paulo, Brazil)
 fracture resistance testing: EMIC DL-2000 (EMIC, São José dos Pinhais, Brazil)

The occlusal veneers exhibited the fracture resistance similar to that of sound teeth.

Al-Akhali et al.
201725

in vitro

 IPS e.max CAD
 VITA ENAMIC®

64 human maxillary first premolars

To evaluate the influence of thermodynamic loading on the durability and fracture resistance behavior of occlusal veneers fabricated from different dental CAD/CAM materials.

 cyclic loading fatigue: dual-axis computerized chewing simulator (Willytec, Feldkirchen-Westerham, Germany)
 fracture resistance testing: Zwick Z010/TN2A (Zwick GmbH, Ulm, Germany)

The materials tested may be considered a viable treatment for the restoration of occlusal surfaces of posterior teeth.

Al-Akhali et al.
201929

in vitro

 IPS e.max CAD
 VITA ENAMIC®

64 human maxillary first premolars

To evaluate the influence of thermomechanical fatigue loading on the fracture strength of minimally invasive occlusal veneer restorations fabricated from different CAD/CAM materials and bonded to human maxillary premolars using the self-etching bonding technique.

 cyclic loading fatigue:
dual-axis computerized chewing simulator (Willytec)
 fracture resistance testing: Zwick Z010/TN2A (Zwick GmbH)

Thermomechanical fatigue decreased the survival rate and fracture strength of all tested CAD/CAM materials when bonded to enamel using the self-etching technique.

Heck et al.
201930

in vitro

 IPS e.max CAD
 Lava™ Ultimate

84 human molars

To determine whether ceramics or nanoceramic composites with an ultrathin layer thickness of 0.3–0.5 mm could be used to restore pressure-loaded occlusal dentin and enamel defects.

 fatigue simulations: computer-controlled chewing simulator (MUC 2; Willytec GmbH, Gräfelfing, Germany)

The tested occlusal veneers are recommended for the treatment of occlusal tooth loss with ultrathin veneers.

Magne et al.
201019

in vitro

 IPS e.max CAD
 Paradigm™ MZ100

30 human maxillary molars

To assess and compare the fatigue resistance
of composite resin and ceramic posterior occlusal veneers.

 fatigue testing:
closed-loop servohydraulics (Mini Bionix II; MTS Systems Corp., Eden Prairie, USA)

CAD/CAM composite resin posterior occlusal veneers had a significantly higher fatigue resistance when compared to the ceramic veneers.

Schlichting et al.
201117

in vitro

• IPS e.max CAD
 Paradigm™ MZ100
 XR experimental blocks (reinforced with short polyethylene fibers)

40 human maxillary molars

To assess the influence of CAD/CAM restorative materials (ceramic vs. composite resin) on the fatigue resistance of ultra-thin occlusal veneers.

 fatigue testing: closed-loop servohydraulics (Mini Bionix II; MTS Systems Corp.)

CAD/CAM composite resin ultrathin occlusal veneers had a significantly higher fatigue resistance when compared to the ceramic veneers.

CAD/CAM – computer-aided design/computer-aided manufacturing.
Table 2. Assessment of the risk of bias

Study

Teeth randomization

Teeth free of caries or restoration

Materials used according to the manufacturer’s instructions

Teeth with similar dimensions

Tooth preparation performed by the same operator

Sample size calculation

Blinding of the operator of the testing machine

Risk of bias

Andrade et al.
201823

Y

Y

Y

Y

N

N

N

medium

Al-Akhali et al.
201725

N

Y

Y

Y

N

Y

N

medium

Al-Akhali et al.
201929

Y

Y

Y

N

N

N

N

high

Heck et al.
201930

N

Y

Y

Y

N

N

N

high

Magne et al.
201019

N

Y

Y

N

N

N

N

high

Schlichting et al.
201117

N

Y

Y

N

N

N

N

high

Y – yes; N – no.
Table 3. Characteristics of the materials used in the included studies

Material

Classification

Manufacturer

Composition

IPS e.max CAD

lithium disilicate glass ceramic

Ivoclar Vivadent
AG, Schaan,
Liechtenstein

SiO2 (57.0–80.0%), Li2O (11.0–19.0%), K2O (0.0–13.0%), P2O5 (0.0–11.0%), ZrO2 (0.0–8.0%),
ZnO (0.0–8.0%), Al2O3 (0.0–5.0%), MgO (0.0–5.0%), coloring oxides (0.0–8.0%)

Lava Ultimate

resin nanoceramic

3M ESPE,
St. Paul,
USA

silica nanomers (20 nm), zirconia nanomers (4–11 nm), nanocluster particles derived from the nanomers (0.6–10 nm), silane coupling agent, resin matrix (Bis-GMA, Bis-EMA, UDMA, and TEGDMA)

VITA ENAMIC

hybrid ceramic
(glass ceramic in a resin interpenetrating matrix)

VITA Zahnfabrik, Bad Säckingen,
Germany

inorganic ceramic content: 86 wt% (silicon dioxide (58–63%), aluminum oxide (20–23%), sodium oxide (9–11%), potassium oxide (4–6%), boron trioxide (0.5–2%), zirconia (<1%), calcium oxide (<1%))

organic polymer content: 14 wt% (UDMA and TEGDMA)

Paradigm MZ100

zirconia–silica ceramic in a resin interpenetrating matrix

3M ESPE,
St. Paul,
USA

Paradigm MZ100: 85 wt% ultrafine zirconia–silica ceramic particles that reinforce a highly cross-linked polymer matrix

polymer matrix: Bis-GMA and TEGDMA

Bis-GMA – bisphenol A-glycidyl methacrylate; Bis-EMA –bisphenol-A ethoxylated dimethacrylate; UDMA – urethane dimethacrylate; TEGDMA – triethylene glycol dimethacrylate.
Table 4. Fracture resistance observed in the included studies

Study

Variables

Results

material

restoration thickness [mm]

cyclic mechanical loading

thermocycling

antagonist material

fracture resistance
[N]
M ±SD

fracture resistance without thermomechanical loading
[N]

fracture resistance
after thermomechanical loading
[N]

conclusions

M ±SD

Me

M ±SD

Me

Andrade et al.
201823

IPS e.max CAD

0.6

1,000,000 cycles at 1-Hz frequency in distilled water at 37°C, a load of 200 N

no thermocycling

a metal sphere with a 6-mm diameter

3,067 ±933

A significantly higher fracture resistance was obtained for 1.5-mm IPS e.max CAD than for the other experimental groups (p = 0.027). There was no significant difference between 0.6-mm VITA ENAMIC, Lava Ultimate and IPS e.max CAD (p = 0.050). The fracture resistance of the sound teeth (3,991 N) did not differ significantly from that of the experimental groups (p = 0.199).

1.5

4,995 ±855

VITA ENAMIC

0.6

2,973 ±635

1.5

3,540 ±986

Lava Ultimate

0.6

3,384 ±922

1.5

3,584 ±954

Al-Akhali et al.
201725

IPS e.max CAD

0.5

1,200,000 mechanical chewing cycles, a vertical load of 98 N

between 5°C and 55°C in distilled water, 30-s dwell time at each temperature with a total of 5,500 thermal cycles at a loading cycle frequency of 2.4 Hz

steatite ceramic balls with a 6-mm diameter

1,408.8 ±215.8

1,335.0

1,545.0 ±175.2

1,560.0

Thermodynamic loading significantly increased the fracture resistance of VITA ENAMIC (p ≤ 0.031). Without thermodynamic loading, lithium disilicate showed a significantly higher fracture resistance than VITA ENAMIC (p ≤ 0.015). After thermodynamic loading, no statistically significant difference was observed between the groups (p ≤ 0.291).

VITA ENAMIC

1,018.5 ±155.5

1,005.0

1,321.0 ±269.1

1,310.0

Al-Akhali et al.
201929

IPS e.max CAD

0.5

1,200,000 mechanical chewing cycles, a vertical load of 98 N

between 5°C and 55°C in distilled water, 30-s dwell time at each temperature with a total of 5,500 thermal cycles at a loading cycle frequency of 2.4 Hz

steatite ceramic balls with a 6-mm diameter

806.1 ±186.9

782.5

470.8 ±428.2

328.5

Thermomechanical fatigue significantly reduced the fracture strength of VITA ENAMIC (p = 0.047). Lithium disilicate exhibited no significant reduction in the fracture strength after thermomechanical fatigue. There was no statistically significant difference between the groups with regard to thermomechanical fatigue.

VITA ENAMIC

767.1 ±130.9

769.5

349.9 ±350.5

98.0

M – mean; Me – median; SD – standard deviation.
Table 5. Fatigue resistance observed in the included studies based on the survival rate

Study

Material

Restoration thickness

Antagonist material

Cyclic mechanical loading

Survival
rate
[%]

Results

Heck et al.
201930

IPS e.max
CAD

0.3–0.5 mm

5-mm highly compacted oxide ceramic (Degussit balls; FRIALIT-DEGUSSIT, Mannheim, Germany)

1,000,000 masticatory cycles with a loading force of 50 N and 100 N and a frequency of 1 Hz

100

There was no significant difference between IPS e.max CAD and Lava Ultimate (p = 0.317) .

Lava
Ultimate

95

Magne et al.
201019

IPS e.max
CAD

1.2 mm at the central groove

7-mm-diameter composite resin sphere (Z100™ MP; 3M ESPE, St. Paul, USA) postpolymerized at 100°C for 5 min

cyclic load applied at a frequency of 5 Hz and 1,400 N, at a maximum of 185,000 cycles

30

A higher fatigue resistance was observed in Paradigm MZ100 compared to IPS e.max CAD (p = 0.002).

Paradigm
MZ100

100

Schlichting et al.
201117

IPS e.max
CAD

0.6 mm at the central groove

7-mm-diameter composite resin sphere (Z100™ MP; 3M ESPE) postpolymerized at 100°C for 5 min

cyclic load applied at a frequency of 5 Hz and 1,400 N, at a maximum of 185,000 cycles

0

A higher fatigue resistance was observed in Paradigm MZ100 compared to IPS e.max CAD (p < 0.001). XR experimental blocks were significantly stronger than IPS e.max CAD (p < 0.001), but not different from Paradigm MZ100 (p = 0.030).

Paradigm
MZ100

60

XR experimental blocks

100

Figures


Fig. 1. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow diagram

References (54)

  1. Lambrechts P, Braem M, Vuylsteke-Wauters M, Vanherle G. Quantitative in vivo wear of human enamel. J Dent Res. 1989;68(12):1752–1754. doi:10.1177/00220345890680120601
  2. Ray DS, Wiemann AH, Patel PB, Ding X, Kryscio RJ, Miller CS. Estimation of the rate of tooth wear in permanent incisors: A cross-sectional digital radiographic study. J Oral Rehabil. 2015;42(6):460–466. doi:10.1111/joor.12288
  3. Loomans B, Opdam N, Attin T, et al. Severe tooth wear: European consensus statement on management guidelines. J Adhes Dent. 2017;19(2):111–119. doi:10.3290/j.jad.a38102
  4. Salas MMS, Nascimento GG, Huysmans MC, Demarco FF. Estimated prevalence of erosive tooth wear in permanent teeth of children and adolescents: An epidemiological systematic review and meta-regression analysis. J Dent. 2015;43(1):42–50. doi:10.1016/j.jdent.2014.10.012
  5. Bartlett D, Ganss C, Lussi A. Basic Erosive Wear Examination (BEWE): A new scoring system for scientific and clinical needs. Clin Oral Investig. 2008;12 Suppl 1(Suppl 1):S65–S68. doi:10.1007/s00784-007-0181-5
  6. Wetselaar P, Lobbezoo F. The Tooth Wear Evaluation System: A modular clinical guideline for the diagnosis and management planning of worn dentitions. J Oral Rehabil. 2016;43(1):69–80. doi:10.1111/joor.12340
  7. Edelhoff D, Beuer F, Schweiger J, Brix O, Stimmelmayr M, Guth JF. CAD/CAM-generated high-density polymer restorations for the pretreatment of complex cases: A case report. Quintessence Int. 2012;43(6):457–467. PMID:22532953.
  8. Zero DT, Lussi A. Erosion – Chemical and biological factors of importance to the dental practitioner. Int Dent J. 2005;55(4 Suppl 1):285–290. doi:10.1111/j.1875-595X.2005.tb00066.x
  9. Bartlett D, Phillips K, Smith B. A difference in perspective – the North American and European interpretations of tooth wear. Int J Prosthodont. 1999;12(5):401–408. PMID:10709520.
  10. Bartlett DW. The role of erosion in tooth wear: Aetiology, prevention and management. Int Dent J. 2005;55(4 Suppl 1):277–284. doi:10.1111/j.1875-595X.2005.tb00065.x
  11. West NX, Joiner A. Enamel mineral loss. J Dent. 2014;42 Suppl 1:S2–S11. doi:10.1016/S0300-5712(14)50002-4
  12. Muts EJ, van Pelt H, Edelhoff D, Krejci I, Cune M. Tooth wear: A systematic review of treatment options. J Prosthet Dent. 2014;112(4):752–759. doi:10.1016/j.prosdent.2014.01.018
  13. van den Breemer CR, Vinkenborg C, van Pelt H, Edelhoff D, Cune MS. The clinical performance of monolithic lithium disilicate posterior restorations after 5, 10, and 15 years: A retrospective case series. Int J Prosthodont. 2017;30(1):62–65. doi:10.11607/ijp.4997
  14. Vailati F, Belser UC. Full-mouth adhesive rehabilitation of a severely eroded dentition: The three-step technique. Part 2. Eur J Esthet Dent. 2008;3(2):128–146. PMID:19655527.
  15. Vaidyanathan TK, Vaidyanathan J. Recent advances in the theory and mechanism of adhesive resin bonding to dentin: A critical review. J Biomed Mater Res B Appl Biomater. 2009;88(2):558–578. doi:10.1002/jbm.b.31253
  16. Johnson AC, Versluis A, Tantbirojn D, Ahuja S. Fracture strength of CAD/CAM composite and composite-ceramic occlusal veneers. J Prosthodont Res. 2014;58(2):107–114. doi:10.1016/j.jpor.2014.01.001
  17. Schlichting LH, Maia HP, Baratieri LN, Magne P. Novel-design ultra-thin CAD/CAM composite resin and ceramic occlusal veneers for the treatment of severe dental erosion. J Prosthet Dent. 2011;105(4):217–226. doi:10.1016/S0022-3913(11)60035-8
  18. Schlichting LH, Resende TH, Reis KR, Magne P. Simplified treatment of severe dental erosion with ultrathin CAD-CAM composite occlusal veneers and anterior bilaminar veneers. J Prosthet Dent. 2016;116(4):474–482. doi:10.1016/j.prosdent.2016.02.013
  19. Magne P, Schlichting LH, Maia HP, Baratieri LN. In vitro fatigue resistance of CAD/CAM composite resin and ceramic posterior occlusal veneers. J Prosthet Dent. 2010;104(3):149–157. doi:10.1016/S0022-3913(10)60111-4
  20. Magne P, Stanley K, Schlichting LH. Modeling of ultrathin occlusal veneers. Dent Mater. 2012;28(7):777–782. doi:10.1016/J.DENTAL.2012.04.002
  21. Sasse M, Krummel A, Klosa K, Kern M. Influence of restoration thickness and dental bonding surface on the fracture resistance of full-coverage occlusal veneers made from lithium disilicate ceramic. Dent Mater. 2015;31(8):907–915. doi:10.1016/J.DENTAL.2015.04.017
  22. Krummel A, Garling A, Sasse M, Kern M. Influence of bonding surface and bonding methods on the fracture resistance and survival rate of full-coverage occlusal veneers made from lithium disilicate ceramic after cyclic loading. Dent Mater. 2019;35(10):1351–1359. doi:10.1016/j.dental.2019.07.001
  23. Andrade JP, Stona D, Bittencourt HR, Borges GA, Burnett Júnior LH, Spohr AM. Effect of different computer-aided design/computer-aided manufacturing (CAD/CAM) materials and thicknesses on the fracture resistance of occlusal veneers. Oper Dent. 2018;43(5):539–548. doi:10.2341/17-131-L
  24. Ilie N, Hilton TJ, Heintze SD, et al. Academy of Dental Materials guidance – Resin composites: Part I – Mechanical properties. Dent Mater. 2017;33(8):880–894. doi:10.1016/j.dental.2017.04.013
  25. Al-Akhali M, Chaar MS, Elsayed A, Samran A, Kern M. Fracture resistance of ceramic and polymer-based occlusal veneer restorations. J Mech Behav Biomed Mater. 2017;74:245–250. doi:10.1016/j.jmbbm.2017.06.013
  26. Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: An updated guideline for reporting systematic reviews. BMJ. 2021;372:n71. doi:10.1136/bmj.n71
  27. Faggion CM. Guidelines for reporting pre-clinical in vitro studies on dental materials. J Evid Based Dent Pract. 2012;12(4):182–189. doi:10.1016/j.jebdp.2012.10.001
  28. Sarkis-Onofre R, Skupien JA, Cenci MS, Moraes RR, Pereira-Cenci T. The role of resin cement on bond strength of glass-fiber posts luted into root canals: A systematic review and meta-analysis of in vitro studies. Oper Dent. 2014;39(1):E31–E44. doi:10.2341/13-070-LIT
  29. Al-Akhali M, Kern M, Elsayed A, Samran A, Chaar MS. Influence of thermomechanical fatigue on the fracture strength of CAD-CAM-fabricated occlusal veneers. J Prosthet Dent. 2019;121(4):644–650. doi:10.1016/j.prosdent.2018.07.019
  30. Heck K, Paterno H, Lederer A, Litzenburger F, Hickel R, Kunzelmann KH. Fatigue resistance of ultrathin CAD/CAM ceramic and nanoceramic composite occlusal veneers. Dent Mater. 2019;35(10):1370–1377. doi:10.1016/j.dental.2019.07.006
  31. Albelasy EH, Hamama HH, Tsoi JKH, Mahmoud SH. Fracture resistance of CAD/CAM occlusal veneers: A systematic review of laboratory studies. J Mech Behav Biomed Mater. 2020;110:103948. doi:10.1016/j.jmbbm.2020.103948
  32. Maeder M, Pasic P, Ender A, Özcan M, Benic GI, Ioannidis A. Load-bearing capacities of ultra-thin occlusal veneers bonded to dentin. J Mech Behav Biomed Mater. 2019;95:165–171. doi:10.1016/j.jmbbm.2019.04.006
  33. Dirxen C, Blunck U, Preissner S. Clinical performance of a new biomimetic double network material. Open Dent J. 2013;7:118–122. doi:10.2174/1874210620130904003
  34. Ioannidis A, Mühlemann S, Özcan M, Hüsler J, Hämmerle CHF, Benic GI. Ultra-thin occlusal veneers bonded to enamel and made of ceramic or hybrid materials exhibit load-bearing capacities not different from conventional restorations. J Mech Behav Biomed Mater. 2019;90:433–440. doi:10.1016/j.jmbbm.2018.09.041
  35. Ma L, Guess PC, Zhang Y. Load-bearing properties of minimal-invasive monolithic lithium disilicate and zirconia occlusal onlays: Finite element and theoretical analyses. Dent Mater. 2013;29(7):742–751. doi:10.1016/J.DENTAL.2013.04.004
  36. Kinney JH, Balooch M, Marshall GW, Marshall SJ. A micromechanics model of the elastic properties of human dentine. Arch Oral Biol. 1999;44(10):813–822. doi:10.1016/S0003-9969(99)00080-1
  37. Bowen RL, Rodriguez MS. Tensile strength and modulus of elasticity of tooth structure and several restorative materials. J Am Dent Assoc. 1962;64(3):378–387. doi:10.14219/jada.archive.1962.0090
  38. Oyafuso DK, Özcan M, Bottino MA, Itinoche MK. Influence of thermal and mechanical cycling on the flexural strength of ceramics with titanium or gold alloy frameworks. Dent Mater. 2008;24(3):351–356. doi:10.1016/J.DENTAL.2007.06.008
  39. Steiner M, Mitsias ME, Ludwig K, Kern M. In vitro evaluation of a mechanical testing chewing simulator. Dent Mater. 2009;25(4):494–499. doi:10.1016/j.dental.2008.09.010
  40. Kern M, Strub JR, Lü XY. Wear of composite resin veneering materials in a dual-axis chewing simulator. J Oral Rehabil. 1999;26(5):372–378. doi:10.1046/J.1365-2842.1999.00416.X
  41. Szesz A, Parreiras S, Reis A, Loguercio A. Selective enamel etching in cervical lesions for self-etch adhesives: A systematic review and meta-analysis. J Dent. 2016;53:1–11. doi:10.1016/j.jdent.2016.05.009
  42. Bedran-Russo A, Leme-Kraus AA, Vidal CMP, Teixeira EC. An overview of dental adhesive systems and the dynamic tooth – Adhesive interface. Dent Clin North Am. 2017;61(4):713–731. doi:10.1016/j.cden.2017.06.001
  43. van Meerbeek B, Yoshihara K, van Landuyt K, Yoshida Y, Peumans M. From Buonocore’s pioneering acid-etch technique to self-adhering restoratives. A status perspective of rapidly advancing dental adhesive technology. J Adhes Dent. 2020;22(1):7–34. doi:10.3290/j.jad.a43994
  44. Sheets JL, Wilcox CW, Barkmeier WW, Nunn ME. The effect of phosphoric acid pre-etching and thermocycling on self-etching adhesive enamel bonding. J Prosthet Dent. 2012;107(2):102–108. doi:10.1016/S0022-3913(12)60033-X
  45. Erickson RL, Barkmeier WW, Kimmes NS. Bond strength of self-etch adhesives to pre-etched enamel. Dent Mater. 2009;25(10):1187–1194. doi:10.1016/J.DENTAL.2009.04.004
  46. Gracis S, Thompson VP, Ferencz JL, Silva NRFA, Bonfante EA. A new classification system for all-ceramic and ceramic-like restorative materials. Int J Prosthodont. 2015;28(3):227–235. doi:10.11607/ijp.4244
  47. Stappert CFJ, Abe P, Kurths V, Gerds T, Strub JR. Masticatory fatigue, fracture resistance, and marginal discrepancy of ceramic partial crowns with and without coverage of compromised cusps. J Adhes Dent. 2008;10(1):41–48. PMID:18389735.
  48. Yu W, Guo K, Zhang B, Weng W. Fracture resistance of endodontically treated premolars restored with lithium disilicate CAD/CAM crowns or onlays and luted with two luting agents. Dent Mater J. 2014;33(3):349–354. doi:10.4012/dmj.2013-240
  49. Rizzante FAP, Soares-Rusu IBL, Senna SS, et al. Flexural strength of minimum thickness ceramic veneers manufactured with different techniques. Quintessence Int. 2020;51(4):268–273. doi:10.3290/j.qi.a44147
  50. Zimmermann M, Ender A, Egli G, Özcan M, Mehl A. Fracture load of CAD/CAM-fabricated and 3D-printed composite crowns as a function of material thickness. Clin Oral Investig. 2019;23(6):2777–2784. doi:10.1007/s00784-018-2717-2
  51. Magne P, Carvalho AO, Bruzi G, Giannini M. Fatigue resistance of ultrathin CAD/CAM complete crowns with a simplified cementation process. J Prosthet Dent. 2015;114(4):574–576. doi:10.1016/j.prosdent.2015.04.014
  52. Kunzelmann KH, Jelen B, Mehl A, Hickel R. Wear evaluation of MZ100 compared to ceramic CAD/CAM materials. Int J Comput Dent. 2001;4(3):171–184. PMID:11862884.
  53. Rosentritt M, Preis V, Behr M, Hahnel S. Influence of preparation, fitting, and cementation on the vitro performance and fracture resistance of CAD/CAM crowns. J Dent. 2017;65:70–75. doi:10.1016/J.JDENT.2017.07.006
  54. Rosentritt M, Krifka S, Strasser T, Preis V. Fracture force of CAD/CAM resin composite crowns after in vitro aging. Clin Oral Investig. 2020;24(7):2395–2401. doi:10.1007/s00784-019-03099-1