DURABILITY COMPARISON OF CHAIR-SIDE GENERATED AND HEAT-PRESSED LITHIUM DISILICATE SINGLE CROWNS SYSTEMATIC REVIEW

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1

Jie Ding

V year, 13 group

DURABILITY COMPARISON OF CHAIR-SIDE

GENERATED AND HEAT-PRESSED LITHIUM

DISILICATE SINGLE CROWNS

SYSTEMATIC REVIEW

Master’s Thesis

Supervisor Lect. Rimantas Ožiūnas

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2 LITHUANIAN UNIVERSITY OF HEALTH SCIENCES

MEDICAL ACADEMY

  FACULTY OF ODONTOLOGY  ORTHOPEDIC CLINIC

DURABILITY COMPARISON OF CHAIR-SIDE GENERATED AND HEAT-PRESSED LITHIUM DISILICATE SINGLE CROWNS

SYSTEMATIC REVIEW Master’s Thesis

The thesis was done

by student ... Supervisor ...

(signature) (signature)

... ...

(namesurname, year, group) (degree, name surname)

... 20…. ... 20….

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EVALUATION TABLE OF THE MASTER’S THESIS   OF THE

TYPE OF SYSTEMIC REVIEW OF SCIENTIFIC LITERATURE

Evaluation:... Reviewer:...

(scientific degree. name and surname)

Reviewing date: ...

No. MT parts MT evaluation aspects

Compliance with MT requirements and evaluation Yes Partially No 1 Summary (0.5 point)

Is summary informative and in compliance with the

thesis content and requirements? 0.3 0.1 0

2 Are keywords in compliance with the thesis

essence? 0.2 0.1 0

3

Introduction, aim and tasks

(1 point)

Are the novelty, relevance and significance of the

work justified in the introduction of the thesis? 0.4 0.2 0 4 Are the problem, hypothesis, aim and tasks formed

clearly and properly? 0.4 0.2 0

5 Are the aim and tasks interrelated? 0.2 0.1 0

6 Selection criteria of the studies, search methods and strategy (3.4 points)

Is the protocol of systemic review present? 0.6 0.3 0

7

Were the eligibility criteria of articles for the selected protocol determined (e.g., year, language, publication condition, etc.)

0.4 0.2 0

8

Are all the information sources (databases with dates of coverage, contact with study authors to identify additional studies) described and is the last search day indicated?

0.2 0.1 0

9

Is the electronic search strategy described in such a way that it could be repeated (year of search, the last search day; keywords and their combinations; number of found and selected articles according to the combinations of keywords)?

0.4 0.1 0

10

Is the selection process of studies (screening, eligibility, included in systemic review or, if applicable, included in the meta-analysis) described?

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4 11

Is the data extraction method from the articles (types of investigations, participants, interventions, analysed factors, indexes) described?

0.4 0.2 0

12

Are all the variables (for which data were sought and any assumptions and simplifications made) listed and defined?

0.4 0.2 0

13

Are the methods, which were used to evaluate the risk of bias of individual studies and how this information is to be used in data synthesis, described?

0.2 0.1 0

14 Were the principal summary measures (risk ratio,

difference in means) stated? 0.4 0.2 0

15

Systemization and analysis of data

(2.2 points)

Is the number of studies screened: included upon assessment for eligibility and excluded upon giving the reasons in each stage of exclusion presented?

0.6 0.3 0

16

Are the characteristics of studies presented in the included articles, according to which the data were extracted (e.g., study size, follow-up period, type of respondents) presented?

0.6 0.3 0

17

Are the evaluations of beneficial or harmful outcomes for each study presented? (a) simple summary data for each intervention group; b) effect estimates and confidence intervals)

0.4 0.2 0

18

Are the extracted and systemized data from studies presented in the tables according to individual tasks?

0.6 0.3 0

19

Discussion (1.4 points)

Are the main findings summarized and is their

relevance indicated? 0.4 0.2 0

20 Are the limitations of the performed systemic

review discussed? 0.4 0.2 0

21 Does author present the interpretation of the

results? 0.4 0.2 0

22

Conclusions (0.5 points)

Do the conclusions reflect the topic, aim and tasks

of the Master’s thesis? 0.2 0.1 0

23 Are the conclusions based on the analysed

material? 0.2 0.1 0

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5 25

References (1 point)

Is the references list formed according to the

requirements? 0.4 0.2 0

26

Are the links of the references to the text correct? Are the literature sources cited correctly and precisely?

0.2 0.1 0

27 Is the scientific level of references suitable for _{Master’s thesis?} 0.2 0.1 0

28

Do the cited sources not older than 10 years old form at least 70% of sources, and the not older than 5 years – at least 40%?

0.2 0.1 0

Additional sections, which may increase the collected number of points 29 Annexes Do the presented annexes help to understand the

analysed topic? +0.2 +0.1 0

30

Practical

Recommen-dations

Are the practical recommendations suggested and

are they related to the received results? +0.4 +0.2 0

31

Were additional methods of data analysis and their results used and described (sensitivity analyses, meta-regression)?

+1 +0.5 0

32

Was meta-analysis applied? Are the selected statistical methods indicated? Are the results of each meta-analysis presented?

+2 +1 0

General requirements, non-compliance with which reduce the number of points

33

General requirements

Is the thesis volume sufficient (excluding annexes)? 15-20 pages (-2 points) <15 pages (-5 points)

34 Is the thesis volume increased artificially? -2

points -1 point 35 Does the thesis structure satisfy the

requirements of Master’s thesis? -1 point -2 points 36 Is the thesis written in correct language,

scientifically, logically and laconically? -0.5 point -1 points 37 Are there any grammatical, style or

computer literacy-related mistakes?

-2

points -1 points 38 Is text consistent, integral, and are the

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6 39 Amount of plagiarism in the thesis. >20% (not evaluated)

40

Is the content (names of sections and sub- sections and enumeration of pages) in compliance with the thesis structure and aims?

-0.2 point -0.5 points

41

Are the names of the thesis parts in compliance with the text? Are the titles of sections and sub-sections distinguished logically and correctly?

-0.2 point -0.5 points

42 Are there explanations of the key terms and

abbreviations (if needed)? -0.2 point

-0.5 points

43

Is the quality of the thesis typography (quality of printing, visual aids, binding) good?

-0.2 point -0.5 points *In total (maximum 10 points):

*Remark: the amount of collected points may exceed 10 points.

Reviewer’s comments: ___________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ _________________________________________ _____________________________________

Reviewer’s name and surname Reviewer’s signature

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7 TABLE OF CONTENTS

SUMARRY ... 8

INTRODUCTION ... 9

1. SELECTION CRITERIA OF THE STUDIES. SEARCH METHODS AND STRATEGY ... 11

1.1 Search strategy ... 11

1.2 Selection Criteria ... 11

1.2.1 Inclusion criteria:... 11

1.2.2 Exclusion criteria: ... 11

Fig 1. PRISMA flow chart for article selection ... 19

2. SYSTEMIZATION AND ANALYSIS OF DATA ... 21

2.1 Literature Search ... 21 2.2 Data Extraction ... 21 3. DISCUSSION OF RESULTS ... 32 CONCLUSIONS ... 35 PRACTICAL RECOMMENDATIONS ... 35 REFERENCES ... 36

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SUMARRY

Clinical relevance and aim:

The goal of this systematic review is to determine the durability of chairside fabricated lithium disilicate single crowns (made with IPS e.max CAD) and laboratory fabricated heat-pressed LD single crowns. That is done by comparing survival rates of CAD/CAM fabricated and conventional laboratory fabricated full lithium disilicate crowns (IPS e.max Press and Empress II) after minimum follow up time of 2 years, up to 12 years.

Materials and methods: Three electronic databases (PubMed/MEDLINE; Springer and Science Direct) were used to conduct evaluation of in vivo studies using different combination of keywords: CAD/CAM and Complications and Dentistry; Chair side and Lithium Disilicate crowns; CAD/CAM and Lithium Disilicate; CAD/CAM & Prosthodontics; Lithium disilicate crown and Failure; Lithium disilicate and Survival rate

The search was performed in accordance with PRISMA statement and articles were selected according to predetermined inclusion criteria.

Results: Fourteen studies were selected for the final analysis from an initial amount of 5770. Overall chairside CAD/CAM fabricated restorations proved to be durable in the long run, with a 10 year follow up survival rate of 83.5%, compared to 87.1% for Empress II and 80% for e.max Press lithium disilicate crowns.

Conclusion: The chairside lithium disilicate CAD/CAM restorations had a limited amount of research and small sample size, however it can be recommended for medium-term use as its durability did not differ significantly from laboratory made restorations. Long term results were better for heat pressed restorations but had a large bias due to loss of patients to follow up.

Keywords: Cad/cam complications, lithium disilicate, dental porcelain failure, ceramic failure, survival rate, chairside lithium disilicate, clinical outcome

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9

INTRODUCTION

Ideal restorative material should satisfy functional and aesthetic requirements and provide long term stability [1]. In this systemic review it was chosen to compare lithium disilicate (LD) single crowns fabricated by two different methods: milled in chair side milling machines and heat-pressed (HP) in the laboratory.

One of the main reasons to this material of choice was its popularity. According to National Dental Practice-Based Research Network, lithium disilicate is 1st choice material for anterior teeth crowns and 3rd for posterior teeth [2]. According to review article by F. Zarone and his colleagues: “Lithium disilicate (SiO2-Li2O) was introduced in the field of glass ceramics in 1998 as a core material, obtained by heat-pressing ingots (Empress 2, Ivoclar Vivadent, Lichtenstein)’’ [3]. At that time the product offered a higher flexural strength (360MPa) than other glass ceramics (like leucite based ones). Later Empress 2 was discontinued and replaced by an improved version which was said to have better physical and optical properties [4]. Even though Empress II was discontinued, there were many follow up studies on this older version of e.max Press with acceptable results. Due to that it was included in current systemic review.

According to scientific literature provided by the manufacturer, the physical properties of the IPS e.max have a slight difference between Press and CAD version (flexural strength of e.max Press – 400 MPa, e.max CAD 360MPa, Fracture toughness e.max Press – 2.7; e.max CAD – 2.5 MPa m0.5₎

[5]. However, according to an independent study, KIC (fracture toughness) is more reliable in e.max

Press than e.max CAD in in vitro study [6]. Empress II and IPS e.max Press has similar biaxial flexural strength, and a difference of about 100 MPa in Weibull’s strength. However, major difference was seen in light translucency tests [7].

Some in vitro studies show that monolithic LD crowns (both CAD/CAM and heat-pressed) are more resistant to fracture compared to multi-layered crowns. It has shown higher fracture load of 1900 N which is comparable to the metal-ceramic standards [8][9][10]. Therefore, LD is also widely used due its promising physical and optical properties [11]-[23].

Although Computer-Aided Design and Computer-Aided Manufacturing (CAD/CAM) is still one of the youngest technologies used in prosthetic dentistry, it is rapidly evolving has been progressively used during the last decade [24][25]. According to different manufactures, it has a big advantage of shorter chair time for aesthetic prosthetic restorations, as well as decreased number of visits. According to literature one of the most widely in this day is Cerec 3 (Sirona, Germany). It was first introduced in 1985 by Dr Mormann and electrical engineer Dr Marco Brandestini. The team

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10 performed the first chairside inlay using their milling and scanning device, which they called CEREC (computer –assisted ceramic reconstruction) [26]

Generally, according to Dawidowitz and Kotick in 2008 there was: “More than 30,000 dentists around the world own scanning and milling machines; 10,000 of these are in the United States and Canada. Worldwide, more than 15 million CEREC restorations alone have been completed” [27][28]. As this material is relatively new, there have not been many studies comparing its clinical results. Therefore, this systemic review aims to compare and see the difference in durability between the two fabrication methods of the same material in in vivo clinical studies and follow ups. Also it is stated in other studies, that the performance of a CAD-CAM system relative to marginal adaptation is influenced by the restorative material. Compared with CAD-CAM, most of the heat-pressed lithium disilicate crowns displayed equal or smaller MD (marginal discrepancy) values [30]. The main interest of many dental practitioners is if the chair-side generated restorations are as durable as more time tested, conventionally produced restorations. In this systemic review it was chosen to compare heat pressed LD single crowns with chair side generated ones.

Aim

To find and compare the survival rates of chair-side fabricated and heat-pressed lithium disilicate single crowns and determine how the fabrication method had an impact on the longevity of the restoration

Tasks

1. Determine the durability by comparing survival rates of two differently fabricated restoration groups of the same material in in vivo clinical studies.

2.. To see the main tendencies in failures and complications of LD crowns and relate to the fabrication method.

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11

1. SELECTION CRITERIA OF THE STUDIES. SEARCH METHODS

AND STRATEGY

1.1 Search strategy

The literature search was conducted by one reviewer using four databases (Pub med, Springer, Science direct ) to determine in vivo studies, that investigate survival rate of full ceramic lithium disilicate crowns in the period from 2 to 12 years. The specific terms and their combinations were used: lithium disilicate, CAD/CAM, Survival Rate, Ceramic Failure; Porcelain Failures, Chairside; clinical outcome. The search results were recorded into separate tables for better visualisation of article quantity.

1.2 Selection Criteria

1.2.1 Inclusion criteria:

- Studies that investigate survival rates and clinical outcomes of heat-pressed LD and chair-side generated CADCAM single crowns.

- Prospective studies, controlled clinical trials

- In-vivo studies on live patients

- Follow-up period of at least 2 years after cementation of restoration - Articles not older than 10 years

- English language articles 1.2.2 Exclusion criteria:

- Studies with no clear statements on the type of restoration and survival rates

- In vitro studies or studies on animals

- Follow-up period of shorter than 2 years after cementation of restoration - FPD’s and crowns on implants

- Single crowns with zirconium framework - Not English articles.

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12 Table 1.1 Pubmed search

Table 1.2 Pubmed search

Keywords Filter Results Date of search

Chair side & Lithium Disilicate crowns

None 6 2017.10.25

Humans 4 2017.10.25

Humans, 10 years 4 2017.10.25

Humans, 5 years 2 2017.10.25

CAD/CAM & Prosthodontics None 2571 2017.10.25 CAD/CAM & Prosthodontics Humans 2350 2017.10.25 CAD/CAM & Prosthodontics Humans, 10 years 1903 2017.10.25 CAD/CAM & Prosthodontics Humans, 5 years 889 2017.10.25

CAD/CAM & Lithium Disilicate None 297 2017.10.25 CAD/CAM & Lithium Disilicate Humans 170 2017.10.25 CAD/CAM & Lithium Disilicate Humans, 10 years 163 2017.10.25 CAD/CAM & Lithium Disilicate Humans, 5 years 121 2017.10.25

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CAD/CAM & Complications & Dentistry

None 242 2017.10.25

Humans 211 2017.10.25

CAD/CAM AND

complications AND dentistry

Humans, 10 years

182 2017.10.25

Humans, 5 years

114 2017.10.25

Lithium disilicate crown & Failure

None 152 2017.10.25

Humans 105 2017.10.25

Humans, 10 years 96 2017.10.25

Humans, 5 years 63 2017.10.25

CAD/CAM & Follow up None 193 2017.10.25

CAD/CAM & Follow up Humans 158 2017.10.25

CAD/CAM & Follow up Humans, 10 years 124 2017.10.25 CAD/CAM & Follow up Humans, 5 years 76 2017.10.25

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Lithium Disilicate & Survival rate

None 721 2017.10.25

Humans 435 2017.10.25

Humans, 10 years 391 2017.10.25

Humans, 5 years 277 2017.10.25

Table 2.1 Springer search

CAD/CAM AND Prosthodontics None 271 2017.11.05 CAD/CAM AND Prosthodontics Dentistry& Article 135 2017.11.05 CAD/CAM AND Prosthodontics 10 years 131 2017.11.05 CAD/CAM AND Prosthodontics 5 years 117 2017.11.05

CAD/CAM AND Lithium Disilicate None 60 2017.11.05 CAD/CAM AND Lithium Disilicate Dentistry& Article 38 2017.11.05 CAD/CAM AND Lithium Disilicate 10 years 38 2017.11.05 CAD/CAM AND Lithium Disilicate 5 years 35 2017.11.05

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15 Table 2.3 Springer search

Chair side AND Lithium Disilicate crowns

None 22 2017.11.05

Dentistry& Article 16 2017.11.05

10 years 16 2017.11.05

5 years 14 2017.11.05

CAD/CAM AND Complications AND Dentistry None 225 2017.11.05 CAD/CAM AND Complications AND Dentistry Dentistry &Article 87 2017.11.05 CAD/CAM AND Complications AND Dentistry 10 years 85 2017.11.05 CAD/CAM AND Complications AND Dentistry 5 years 76 2017.11.05

Lithium disilicate crown AND Failure

None 103 2017.11.05

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16 Lithium disilicate

crown AND Failure

10 years 41 2017.11.05

5 years 35 2017.11.05

CAD/CAM & Follow up None 146 2017.11.05

CAD/CAM & Follow up Dentistry &Article 177 2017.11.05

CAD/CAM & Follow up 10 years 163 2017.11.05

CAD/CAM & Follow up 5 years 146 2017.11.05

Lithium Disilicate Ceramics & Dentistry

None 159 2017.11.05

Dentistry &Article

64 2017.11.05

10 years 63 2017.11.05

5 years 54 2017.11.05

Table 3.1 Science Direct search

CAD/CAM & Prosthodontics None 787 2017.11.25 CAD/CAM & Prosthodontics 10 years 608 2017.11.25 CAD/CAM & Prosthodontics 5 years 500 2017.11.25

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17 Table 3.2 Science Direct search

CAD/CAM & Lithium Disilicate None 542 2017.11.25 CAD/CAM & Lithium Disilicate 10 years 507 2017.11.25 CAD/CAM & Lithium Disilicate 5 years 371 2017.11.25

None 61 2017.11.25

10 years 57 2017.11.25

5 years 50 2017.11.25

None 595 2017.11.25

10 years 462 2017.11.25

5 years 343 2017.11.25

None 496 2017.11.25

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18 Lithium disilicate

crown & Failure

5 years 360 2017.11.25

None 11 394 2017.11.25

10 years 3 859 2017.11.25

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19 Fig 1. PRISMA flow chart for article selection

Records identified through database searching: PubMed 1542 studies, Springer 447 studies,

Science Direct 3751 (n = 5770) S cre ening Inc luded Eligi bil it y Ide nti fic ati on

Records after duplicates removed (n = 4985) Records screened (n = 3985) Records excluded (n = 3753) Titles of articles assessed for eligibility

(n = 232)

Articles excluded, with reasons (n = 180) Studies included in qualitative synthesis (n = 14) Abstracts of articles assessed for eligibility

(n = 52)

Duplicates excluded (n = 815)

Articles excluded, with reasons

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20 Table 4 Risk of bias

Study Domain Overal RoB

Judgement Bias in Selection of Participants Bias in Performance (inconsistent number of patiens) Bias Due to Missing Data Bias in Measurement of outcomes Bias in Selection of Reported Results Bias in incomplete Follow-up Seydler and Schmitter 2015

low medium low low low medium low/medium

Fasbinder et. al 2010

medium low low medium low medium low/medium

Reich and Schierz 2012

low low low low low low low

Rauch el al 2016

Rauch el al 2017

Akin et al high low low medium low low medium/low

Huettig and Gehrke

2016

high high medium medium high medium medium/high

Gehrt et. Al 2012 low low low low low low low

Y.Yang et al 2016 low medium medium medium medium medium medium

Van den Breemer et. Al 2017

high high High High high high high

Simeone and Gracis 2015

high medium medium low low medium medium

Toman and Toksavul 2015

low high medium low low low medium

Valenti and Valenti 2009

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21

2. SYSTEMIZATION AND ANALYSIS OF DATA

2.1 Literature Search

The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were used to monitor the results in this systematic review.

The flow chart depicts the results from headmost electronic search using three databases initial amount of 5770 studies (PubMed 1542 studies, Springer 447 studies, Science Direct 3751 studies). The first screening decreased the number of studies to 4985 studies by excluding the duplicates (815studies).

During the second screening 232 articles were selected by a manual search of the titles. (3753 studies excluded). The abstracts were reviewed on the third screening, excluding 180 studies (52 were left). Whole articles were read to evaluate suitability applying chosen inclusion/exclusion criteria. As a result, fourteen studies fulfilled inclusion criteria.

2.2 Data Extraction

Data extraction was performed according to relevance to systematic review, number of participants and restorations, type of study, mean observation time, general shortened information about the teeth that were restored, the fabrication method as well as the machine used (if the information was provided). Preparation guidelines, types of cements, restoration quantity after dropouts. The time interval of failures and complications, as well as cumulative complication/failure free rate and survival rate. No meta-analysis was performed due to diversity and shortcomings of information in some studies.

Table 5

Total number of fourteen studies were included in this systemic review (six prospective clinical studies, four retrospective clinical studies, two clinical evaluation.). The average observation time was 5.9 years, the shortest studies were 2 years [11][12][16] and longest of 12.8years [20]. Five of them were exclusively evaluating the results of chair side generated lithium disilicate restorations with a mean observation time from 2 to 10 years and one [16] was a mixed study with 2 year follow up of both chair-side and heat pressed crowns. All of those restorations were fabricated by CEREC (Sirona, Germany) milling machine and IPS e.max CAD LD [12][13][14][15][16]. Other seven studies included conventionally made heat-pressed LD restorations with a mean observation time from 3 to 12.8 years. Materials were either IPS Empress II or IPS e.max Press [17][18][19][20][21][22][23].

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22 Total number of included patients (before dropouts) from all studies was 5200 with an average of 400 per study. Total number of examinable restorations was 5513 single crowns with the average of 424 per study. The information for restored teeth vitality was present in five studies with a total number of 296 vital teeth and 194 endodontic treated teeth, which were all evaluated before the placement of crown.

The total number of posterior teeth restored with LD crown was 1278 and anterior teeth 4163 (excluding one study, in which the information was unidentified) [18]. In CADCAM related articles, only one study with 2 year follow up [16] of 15 anterior crowns was present, all the other restorations were placed on posterior teeth. Therefore, most of the anterior crowns were made by conventional method.

Most of the studies were performed in University setting (six) with exception of three computer aided manufactured studies, that were split and performed in both University and Private settings. Three studies was performed solely in Private setting [11].

Overall, 7 types of cement was used in all studies making it hard to evaluate the influence of cement on failures and complications.

The mean for circumferential prep was 1.1mm, 1.8mm for incisal reduction and 1.8mm for occlusal reduction. The step was either chamfer or shoulder. However one study was not containing this information [20].

Table 6

(The results are also arranged in Figure 2 and Figure 3)

As mentioned earlier, three CADCAM related studies (by Reich and Schierz and Rauch and colleague) were actually included the same patients and restorations, but separated into three articles with different follow up time (4; 6 and 10 years). Due to that, it was merged into one row and subdivided in the tables[13][14][15]

In two RCS [20][21] both e.max Press and Empress II materials were examined and in one CCT [16] e.max CAD and Press were evaluated. Therefore, they were subdivided in the table and failures and the rates were counted separately. Also in some studies definite follow up year was provided by the author with number of examined restorations, as a result some were included in table.

After dropouts, the biggest number of examined crowns (the number of earliest follow ups) was 961, with 133 e.max CAD, 407 e.max Press and 421 Empress II crowns. Failures and complications were visualised in fig 1, excluding study by Y.Yang and colleagues due to its large sample size (136 failures and complications) [19].

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23 The approximate time of occurred failures in two RCT by Van den Breemer et al and Y.Yang et al was impossible to identify. Therefore the total amount of failures was recorded for the period from 1 to 19.2years (mean 12.8y) in first and 1 to 5 years in second study [19][20].

Cumulative survival rate fluctuated from 79% to 100% with the total mean of 94%. CADCAM group – 94.6% (2 to 10 years); HP group – 94.7% (2 to 15years).

Complication free rate (was reported in all the CAD group studies and was not found in 4 HP studies). Fluctuated significantly from 70.1% to 100%. The mean value was 85.9%. CADCAM group had the mean of 85.7%; HP group– 92%.

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24 Fig. 2. Complications and Failures

Fig. 3. Complication and Survival Rates . 1 1 2 2 ₁1 3 3 3 ₁ 1 1 3 3 3 2 1 1 1 1 1 1 1 2 3 1 1 2 3 4 1 ₄ 1 1 4 ₁₃ 0 2 4 6 8 10 12 14

Complications and Failures

>1 year 1-2y 2-4y 4-6y 6-8y 8-10y >10 1-19,2y

93.3 0% 96.80 % 83% 70.1 0% 71% 100% 93.3 0% 92.9 0% 92.9 0% 92.7 0% 100% 100. 00% 96.3 0% 87.6 0% 83.5 0% 100% 100% 96.8 0% 94.8 0% 96.5 0% 81.3 0% 98.2 0% 87.1 0% 95.5 0%

COMPLICATION AND SURVIVAL RATES

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25 Table 5.1 Description of Studies

Author & Year Type of Study Mean Obs Time Fabrication Method & Place Machine & Material Used No of P No of Exam LD Cr Vital and Endo treated Teeth Group of Teeth Type of cement Prep Setting Circum Inc Red Occl Red Seydler and Schmitter 2015 CE 2y Chair side CAD/CAM CEREC MX XL 60p 30 14 Vital 16 Endo 30 Molars MA IV NR Private Fasbinder et. al 2010 CE 2y Chair side CAD/CAM CERER 3 IV / IPS e.max CAD 43p 62 20 Prem 42 Mol 23 – MA IV 39 – EC IV 1.2mm University - 1.5-2mm Reich and Schierz 2012 Rauch el al 2016 Rauch el al 2017 PCS 4y 6y 10y Chair side CAD/CAM CERER 3 IV / IPS e.max CAD LT 34p 34 17 Vital 17 Endo 7 Prem 27 Mol 34 – MS IV 1 – RelyX 3M (after debond) 1mm University/ Private - 1.5-2mm Akin et al CCT 2y Chair side CAD/CA< CEREC IPS e.max CAD 15p 15 17 Vital 13 Endo Anterior 15 Variolink II IV 1mm University 1.5-2mm Lab made Conv Furn

e.max Press 15p 15 Anterior 15 - Huettig and Gehrke 2016

PFU 3y Lab made

Conv Furn/ IPS e.max Press 58p 327 - Anterior 176 Posterior 151 MA IV Variolink IV RelyX 3M 0.8-1mm University >1mm >1mm

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26 Table 5.2 Description of Studies

Author & Year Type of Study Mean Obs Time Fabrication Method & Place Machine & Material Used No of P No of LD SC Vital and Endo treated Teeth Group of Teeth Type of

cement Prep Setting

Gehrt et.

Al 2012 PCS

6.5y

(3-9y) Lab made

Conv Furn/ EP 600 IV 41p 104 - - Variolink II IV / Vivaglass IV 1mm University 1.5-2mm 1.5-2mm Y.Yang et al 2016 RCS 5y Lab made Conv Furn e.max Press 4634p 4180 - Anterior 3667 Premolar 403 Molar 110 RelyX 1-1.5mm University 2mm 2mm Van den Breemer et. Al 2017 RCS 12.8y (1-19.2y) Lab made Conv Furn Empress II 41/ e.max Press 43 13p 87 - Prem 41

Mol 35 Nexus 2 - University

Simeone and Gracis 2015 RCS 4.6y (1.8-7.5y) Lab made Conv Furn/ Empress II 35cr e.max Press 240cr 106p 275cr Vital 138 Endo 137 Anterior 106 Posterior 169 MA IV/ Variolink / RelyX 1.5mm Private 2mm 2mm Toman and Toksavul 2015 PCS 8.6y

(1-13y) Lab made

Conv Furn/ Layer Techn Empress II IV 35p 121 Vital 110 Endo 11 6 with GFP Anterior 98 78 Inc 20 Can Posterior 98 14 Prem 9 Mol Variolink II IV 1-1.3mm University 1.5mm 2mm

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27 Valenti and

Valenti 2009

RCS 10y Lab made Conv Furn

Empress II IV 146 263 NR Anterior 101 Posterior 160 Variolink II IV Shoulder 1mm Private 2mm 2mm Abbreviations:

LD – lithium disilicate; SC – Single Crown; P- participants; Exam- examinable; CE – Clinical evaluation; PCS– Prospective clinical study; PFU – prospective follow up; RCS- retrospective case series/retrospective clinical study; CCT controlled clinical trial

No – Number; Conv -conventional; furn- furnace Lab- laboratory; Fail –failure; Fract –fracture; Inc- incisor; Can –canine; Prem- premolar; Mol-molar; IV – Ivoclar Vivadent; ; Prep- preparation; Circum– circumferential; Inc Red – Incisal reduction, Occl Red – Occlusal reduction; Layer. Techn – Layering Technique; Obs – observation; MA – Multilink Automix; MS – Multilink Sprint; RelyX – RelyX Unicem ; EC – Experimental Cement;

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28 Table 6.1 Failures, complications and survival rates after dropouts

Author and Year Rest Material Check up Year After Dropouts (crowns)

Failures and Complications Cumulative Complication

free Rate

Cumulative Survival

Rate >1y 1-2y 2-4y 4-6y 6-8y

8-10y >10y Seydler and Schmitter 2015 IPS e.max CAD 2y 30 NR 2 endo prob NR NR NR NR NR 93.3% 100% Fasbinder et. al 2010 IPS e.max CAD 2y 62 NR 1 debond cr (due to cement) 1 debond Cr (due to cement) NR NR NR NR 96.8% 100% (the crowns were intact and rebond) Reich and Schierz 2012 Rauch et al 2016 Rauch el al 2017 IPS e.max CAD 4y 26 NR 2 changed sensibility 1 endo tr 1 sec car 1 deb cr (was reb) 1 fract cr NR NR NR NR 83% 96.3 % 6y NR NR NR NR 70.1% 87.6% 10y 1 Sec Car 1 fract abut 1 severe endo prob 1 root fract NR 1 Severe Car lesion cause Cr replaced 71% 83.5% Akin et al 2014 IPS e.max CAD 2y 15 NR NR NR NR NR NR NR 100% 100% IPS e.max Press 2y 15 NR 1 minor fract NR NR NR NR NR 93.3% 100%

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Author and Year Rest Material Check up Year After Dropouts (crowns)

Failures and Complications Cumulative

Complication free Rate

Cumulative Survival

Rate >1y 1-2y 2-4y 4-6y 6-8y 8-10y >10y

Huettig and Gehrke 2016 IPS e.max Press 2y 60 NR NR 2 cr fract NR NR NR NR 94.6% 98.2% 4y 33 1 cr fract NR NR NR 92.9% 96.8% Gehrt et. Al 2012 IPS e.max Press 5y 62 1 chip 1 extract due to severe endo prob 1 chip 1 extract due to sec car NR NR NR 95.3% 97.4% 8y 27 1 chip 1 extract due to severe endo prob 1 chip 1 extract due to sec car 1 chip 1 crack 2 endo tr 1 fract NR 82.9% 94.8% Y.Yang et al 2016 IPS e.max Press 5y NR-

136 failures and complications – mostly chip and fract

(117 Anterior, 10 Premolar, 9 Molar)

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Author and Year Rest Material Check up Year After Dropouts (crowns)

Failures and Complications _Cumulative Complicatio n free Rate Cumulati ve Survival Rate >1y 1-2y 2-4y 4-6y 6-8y 8-10y >10y

Van den Breemer et. Al 2017 IPS e.max Press- 43 5y

43 9 fail due to debond, sec car, fract of bulk mat NR

92%

10y NR 85.5%

IPS Empress II -

33 Cr

33 4 fail due to debond, sec car, fract of bulk mat

15y NR 81.9% Simeone and Gracis 2015 IPS e.max Press - 240 Cr 4.6y 240 1 GFP

1 chip NR 1 chip 1chip NR NR NR 92.7%

(15 cr debond) 98.3% IPS Empress II - 35 Cr 35 NR 1 GFP NR NR NR NR NR 97.1% Toman and Toksavul 2015 IPS Empress II 5y 79 1 cerv fract (cr intact) NR NR 3 cerv fract (cr intact) NR NR NR NR 95.2% 9y 22 NR NR 1 fract NR 2 fract 1 extr 1 cerv fr (cr intact) NR 87.1% Valenti and Valenti 2009 IPS

Empress II 10y 261 NR NR 1 chip

1 core fail 1 core fail 3 chip NR NR NR 95.5%

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31 Colour coding:

Yellow – chairside IPS e.max CAD Blue – Lab made IPS Empress II Green – Lab made IPS e.max Press

Pink – Mixed studies (have more than one type of LD single crown fabrication) White- No information was provided

Abbreviations:

Occur – Occurred; Rest – restorative; NR - data not recorded; Sec Car – secondary caries; chip – chipping; Cerv fract – cervical fracture, Drop – dropouts; No- number; Compl – complications; exam – examined; bulk mat – bulk material; prob – problem; debond – de-bonded; rebond – re-bonded; Exam – examined; GFP – glass fiber post failure.

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32

3. DISCUSSION OF RESULTS

In the process of review it was discovered, that in all of the chosen studies, no patients with periodontal pathology were included. Bruxism patients were excluded or treated for bruxism before restorative treatment.

For better accuracy of results and strong tendency in articles, it was chosen to compare three lines of lithium disilicate materials from the same manufacturer (Ivoclar Vivadent): IPS e.max CAD, IPS e.max Press and IPS Empress II. The following were abbreviated and categorised to CAD group and heat pressed (HP) group. According to scientific literature [7][5] both e.max CAD and e.max Press were released as an upgrade of Empress II lithium disilicate. The company introduced enhanced aesthetics and mechanical stability.

Although Empress II was discontinued in 2009 after the e.max line was released, before that it was widely used in prosthetic dentistry for its durability and aesthetic results. Scientific documentation provided by Ivoclar Vivadent displays slight difference in biaxial flexural strength (Empress II 410 MPa; e.max Press 450MPa) and Empress II even displays a slightly better accuracy of fit. On the other hand, the e.max line has shown to have up to 10 times better light transmission, therefore offering better translucency and more aesthetic results[5][7].

Chairside CAD/CAM related studies had a total amount of 152 participants. Total number of examinable restorations was 141 crowns. After dropouts total amount of examined crowns decreased to 133 restorations. Only 5.7% was lost in follow ups, making CAD/CAM group’s results reasonably more precise. However studies with small amount of participants have an increased risk of selection bias.

For conventional restorations number was significantly higher with total number of 414 participants and 1192 examinable restorations. After dropouts and taking the longest follow up time in each study, 709 single crowns were examined, meaning 483 (40.5%) were lost to follow up, significantly increasing risk of bias. RCT by Y.Yang et al was excluded in this calculation due to insufficient information about drop outs. [19]

All the studies have met the requirements prepared by Ivoclar Vivadent for full ceramic anterior posterior crowns. In addition, according to in vitro results of dynamic loading, CAD CAM lithium disilicate SCs should have a thickness of at least 1.5mm to withstand occlusal loads in posterior areas [29]

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33 The survival rate was considered equal in some studies. However in one study by Fastbinder and his colleagues, survival rate was 100% despite the fact that 2 crowns has de-bonded in the course of study. The de-bonded crowns were intact so it was considered as the failure of the experimental cement used in the study. Therefore, they were re-cemented. The mean cumulative survival rate for chairside CAD/CAM crowns was 94.6% with highest in 2 year follow-up (100%) [12] and lowest in 10 year follow up (83.5%)[15] The most common failures and complications in chairside fabricated restorations occurred due to de-bonding of crowns and secondary caries. No chippings and one case of crown fracture occurred on 2nd year of recall in Reich and Schierz, and Rauch and colleagues studies. Absence of chippings are one of the biggest advantages of monolithic crowns and were also proven to be so in other studies[13][14][15].

Conventional lab made fabrications or heat pressed group had a mean survival rate of 94.7% with the highest in 2 year follow up (100%) by Akin et al[16] and lowest in 15 year RCS by Van den Breemer (81.9%) [20] The main reason of failure were chips and fractures. Some studies were solely done on Empress II LD and some were performed on both e.max Press and Empress II. In the table 6, when information was provided by the author, the two lithium disilicate HP groups were subdivided. The mean survival rate for e.max Press restorations is 94% with highest result in Simeone and Gracis retrospective clinical study with mean 4.6 year follow up (98.3%) and lowest in study by Gehrt and colleagues (94.8%) with 8 year follow up[18][22].

For Empress II restorations, mean and survival rate is 93.7% with highest result in Simeone and Gracis RCT with 97.1% and lowest in Toman and Toksavul (9 year follow up) with 87.1% According to some of the articles with the longest follow up time, the chair-side restoration and lab made restorations survival rate do not differ drastically in some studies: 83.5% for e.max CAD crowns 10 year follow up [15], and in Van den Breemer and colleague’s 10 y 85,5% [20]. However, it was a surprise to see the survival rate higher for Empress II restorations in Van den Breemer et al study, however it was indicated in the study, that 7 failures out of 9 occurred due to fracture of bulk material. Also Empress II had shown excellent survival rates in other 10 year follow ups by Valenti and Valenti; and Toman and colleagues. According to other articles [31] the most common course for failure was also fracture of the material. Moreover, molars seemed to have a worse prognosis than premolars. However, Empress II system could be also considered as a durable alternative, as the survival rate is comparable with e.max CAD and Press restorations.

Short term survival rates of few years, showed excellent results of both HP and CAD groups (100%). CAD group had survival rate of 96.3% in 4 year follow up, which was almost identical to results in heat-pressed ceramics 4-5year follow ups with results of 96.8% [17] 97.4% [18] ; 96.5% [19] 92% [20]; 97.6 [21]; 95%[22] However, in 6 year follow up, the result in CAD group had dropped by

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34 almost ten percent – from 96.3% to 87.6%, while HP group did not exhibit a big difference in most of the studies.

Generally the mean survival rates for CAD and HP restorations did not differ drastically (94.6% and 94.7%) but HP group had shown slightly better medium to medium-long term results, which may indicate the restorations being more durable. However, CAD group had more accurate follow up result and much lower risk of bias compared to the HP group leaving a chance of inaccuracy of results. Also the sample size of CAD group was much smaller compared to HP group, so still insufficient amount of studies were done on chair side fabricated LD single crowns. Chips and cracks seem to be the most common cause for complications and failure (mostly in layered restorations), followed by crown fractures and endodontic problems. Furthermore, complications were occurring more commonly on endodontically treated teeth.[22] The tendency to micro cracks and other fatigue failures were accentuated in other studies as well [3].

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35

CONCLUSIONS

Within the limitations of this systematic review, the following conclusions were drawn:

1. Results for chair-side CAD/CAM restorations and conventionally fabricated restoration did not differ significantly, both can be used for medium-term restorations. However, heat pressed restorations displayed slightly better results for medium-long term results.

2. Chairside fabricated crowns exhibited no chipping and less fractures and laboratory made restorations seemed to have less secondary carious problems.

Limitations of studies

Due to variating information and patients lost to follow up in conventionally made restoration group, the results might not be completely accurate. Chair side generated restorations had small sample size and were mostly performed on posterior teeth.

PRACTICAL RECOMMENDATIONS

Both computer assisted and laboratory used restorations are recommended for anterior and posterior single crown restorations for medium term restorative treatment. However, for long term restorative treatment, heat pressed monolithic restorations seem to be a better choice of material.

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36

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DURABILITY COMPARISON OF CHAIR-SIDE GENERATED AND HEAT-PRESSED LITHIUM DISILICATE SINGLE CROWNS SYSTEMATIC REVIEW

Jie Ding

DURABILITY COMPARISON OF CHAIR-SIDE

GENERATED AND HEAT-PRESSED LITHIUM

DISILICATE SINGLE CROWNS

SYSTEMATIC REVIEW

EVALUATION TABLE OF THE MASTER’S THESIS OF THE

TYPE OF SYSTEMIC REVIEW OF SCIENTIFIC LITERATURE

SUMARRY

INTRODUCTION

1. SELECTION CRITERIA OF THE STUDIES. SEARCH METHODS

AND STRATEGY

1.1 Search strategy

1.2 Selection Criteria

2. SYSTEMIZATION AND ANALYSIS OF DATA

Complications and Failures

COMPLICATION AND SURVIVAL RATES

3. DISCUSSION OF RESULTS

CONCLUSIONS

PRACTICAL RECOMMENDATIONS

REFERENCES

EVALUATION TABLE OF THE MASTER’S THESIS   OF THE