Additively Fabricated Permanent Crown Materials: An Overview of Literature and Update

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The context in this manuscript is too limited. The purpose of the study, along with the new experimental design, should be revised for better clarity. Additionally, the manuscript lacks sufficient updates and details regarding the latest advancements in the field.

Comments on the Quality of English Language

Quality of English Language is okay.

Author Response

Comment: The context in this manuscript is too limited.

The purpose of the study, along with the new experimental design, should be revised for better clarity.

Additionally, the manuscript lacks sufficient updates and details regarding the latest advancements in the field.

Response: Thank you for your comment. I totally agree with your comments and recommendations. This review focused on printed crowns excluding all other studies conducted on specimens.  According to the search period, the most updated published articles are not included. Based on the comments and recommendations, search time was extended to December 2024 however, no study eligible to be included as no study investigated printed crown.  More details and modifications have been made to improve the quality of study. I hope all modifications meet the required criteria.

Reviewer 2 Report

Comments and Suggestions for Authors

The idea for the article is interesting, I like to read publications related to 3D printing, but as a recentent I have a few reservations about this work

In the abstract it would be good to add information about how many articles were found, which of them were used, e.g. 200 publications were found, 15 were extracted, which were discussed in detail, because certainly not all of them, thank you

 

Introduction

lines 32-35 are a torch such an advertisement, apart from the undoubted advantages 3D technology also has disadvantages, the need to use special tools, often programs that are closed and limited to one manufacturer. Zirconium oxide, etc. Do not use the phrase 3D in every second sentence.

line 54

with this biocompatibility is also a big abuse, the question e.g. underpolymerized SLA is very cytotoxic.

line 84

the learning curve? what do you understand by this term?

What is the thesis that you put before these literature studies?

line 169

it would be good to provide numerical values, e.g. Smith wrote that a printed crown has a mechanical resistance of e.g. 200 MPa, but New writes about values ​​of e.g. 250 MPa.

3D-printed 3Y-TZP ceramic-based crown - what does this abbreviation mean, if you are using it for the first time, it is good to explain it.

Clinical performance and other subtitles would be good to separate with an additional space or another letter, to make it more legible

 

line 200

d 100% good grade - what do you understand by this term?

line 211

other studies indicate that 3D printed materials must be properly polished, otherwise their color stability remains very poor. see: Raszewski Z, Chojnacka K, Mikulewicz M. Effects of Surface Preparation Methods on the Color Stability of 3D-Printed Dental Restorations. J Funct Biomater. 2023 May 5;14(5):257. doi: 10.3390/jfb14050257

Shishehian A, Firouz F, Khazaee S, Rajabi H, Farhadian M, Niaghiha F. Evaluating the color stability of 3D-printed resins against various solutions. Eur J Transl Myol. 2023 Jul 5;33(3):11493. doi: 10.4081/ejtm.2023.11493.

 

and what are the limitations of your research, what would you like to do with such a developed topic?

 

In [researches even such as research literature there is some results and discussion of this you lack.

 

good luck in further research!

Author Response

Introduction

 

Comment: lines 32-35 are a torch such an advertisement, apart from the undoubted advantages 3D technology also has disadvantages, the need to use special tools, often programs that are closed and limited to one manufacturer. Zirconium oxide, etc. Do not use the phrase 3D in every second sentence.

Response: Thank you for your comment. Like this point were reviewed through the manuscript and highlighted.

 

Comment:  line 54, with this biocompatibility is also a big abuse, the question e.g. underpolymerized SLA is very cytotoxic.

Response: Thank you for your comment. This paragraph is related to ceramic crown not printed one. Please, see highlighted statements in the same paragraph.  

 

Comment:  line 84the learning curve? what do you understand by this term?

Response: Thank you for your valuable comment. The statement was rephrased. Please, see highlighted statement L, 86-88

 

Comment: What is the thesis that you put before these literature studies?

Response: Thank you for your comment. It was noticed that more researches were conducted using 3D printed technology for permanent crown fabrication using different materials. But there is a lack of information regarding the implementation of this technology clinically. Therefore this review focused on the fabricated crown (with crown configuration) in different specialties and excluding all studies investigated specimens (bar- or disc-shape). This was a reason for low number of included studies even with huge number of studies published in this area.

 

Comment: line 169 it would be good to provide numerical values, e.g. Smith wrote that a printed crown has a mechanical resistance of e.g. 200 MPa, but New writes about values of e.g. 250 MPa.

Response: Thank you for your comment and recommendation.

 

Comment: 3D-printed 3Y-TZP ceramic-based crown - what does this abbreviation mean, if you are using it for the first time, it is good to explain it.

Response: thank you for you comment. The full word of abbreviation added.  It is the name of ceramic “yttrium-stabilized tetragonal zirconia polycrystal”

 

Comment: Clinical performance and other subtitles would be good to separate with an additional space or another letter, to make it more legible

Response: Thank you for your comment. Clinical performance with more elaborations is added and highlighted.

 

Comment:  line 200 d 100% good grade - what do you understand by this term?

Response: Thank you for the comment. The statement was revised and paraphrased for more readability.

 

Comment:  line 211: other studies indicate that 3D printed materials must be properly polished, otherwise their color stability remains very poor. see: Raszewski Z, Chojnacka K, Mikulewicz M. Effects of Surface Preparation Methods on the Color Stability of 3D-Printed Dental Restorations. J Funct Biomater. 2023 May 5;14(5):257. doi: 10.3390/jfb14050257

Shishehian A, Firouz F, Khazaee S, Rajabi H, Farhadian M, Niaghiha F. Evaluating the color stability of 3D-printed resins against various solutions. Eur J Transl Myol. 2023 Jul 5;33(3):11493. doi: 10.4081/ejtm.2023.11493.

Response: thank you for your comment and recommendations. This point was added with supported reference. Please, see highlighted part Line No.

      

Comment:  what are the limitations of your research, what would you like to do with such a developed topic?

Response:Thank you for your comment. Study limitations and future recommendations added.

 Comment: In [researches even such as research literature there is some results and discussion of this you lack.

Response: Thank you for your comment. This was due to the limited and the focus area of review (printed crown). However some updates in the revised version updated with more results in results section.

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Author,

I have read your manuscript “Additively fabricated permanent crown materials: An overview of literature and update”, The manuscript is within the modern dental era. This manuscript could be of great interest to the readers, particularly because it includes both ceramic and resin-based dental crowns. There are comments, which I hope you will find helpful to further improve the quality of your manuscript.

 

General Major Issues:

The manuscript did not include all the additive manufacturing techniques and only concentrated on some daughter technologies and derivative technologies of the VAT photopolymerization.

I suggest that you add all the technologies according to the ISO classifications that could be used for the production of dental crowns. Those that cannot produce dental parts as sheet lamination can be mentioned only by name.

Or less favorable option, you can change the title of your manuscript to “Additively fabricated permanent crown materials for vat photopolymerization technologies: An overview of the literature and update” and the content of your manuscript accordingly. I prefer the first option that you add more even if that took time, to enhance the impact of your article on the literature, particularly adding the last updates.

 

Another important matter is that 24 studies are very few for ceramic and resin crowns, there are tremendous studies numbers in the literature focusing on ceramic and resin crowns, to the best of my knowledge! I think you could have better insight into the literature if a second reviewer helped with the search strategy. I have never been able to execute a thorough review without the help of a second or a third reviewer.

I took a fast blink to PubMed and I found that “Revilla-León” alone has more than 10 studies on printed crowns, and “Kim JS”, “Kim GM”, or “Kim HJ” and others from South Korea possess around 30 studies or more, and so on.

Given that you talked about mechanical, physical properties, accuracy, and other properties, you should have found hundreds of papers on dental crowns or materials applied for printing ceramic and resin crowns.

The title of your review is focusing on the crown materials! Although the manuscript is not, you did not include material composition, solid loading, filler content, brands, processing, the impact of printing parameters, or postprocessing such as debinding, sintering, or postcuring. There is no data aboutthe microstructure of the produced crowns, grains and their boundaries, and so on. Please add more or consider changing the title.

 

Minor issues

Abstract

How many articles were found in each database, or in total, and how many studies are included?

The abstract is more general speaking. It needs to be more focused on the subject of the manuscript, factors materials, famous technologies…etc.

The keywords are also weak, this is your section, try to add important keywords so your manuscript will pop up in the research engine when the readers are looking for certain subjects.

 

Introduction

 The introduction is mainly so generic, resembling more of a magazine talk than a scientific paper. It needs only polishing of the English language, and to be more specific. For instance, when you say 3D printing is better than conventional approaches! So what are these conventional approaches, there are manual methods or metal casting, or manual methods with ceramic heat press, or partial digital workflow with milled wax and resin patterns, or CNC milled restorations through full digital or partial digital workflow. I suggest that you concentrate your comparison against manual methods or CNC milling technology. In this way, the readers will know exactly what you are comparing. Moreover, In which aspects are additive manufacturing technologies better? You have to name these aspects relying on previous studies or evidence-based projects.

Suggestions

Branco, A.C.; Colaço, R.; Figueiredo-Pina, C.G.; Serro, A.P. Recent Advances on 3D-Printed Zirconia-Based Dental Materials: A Review. Materials 2023, 16, 1860. https://doi.org/10.3390/ma16051860

 

Ahmed Yaseen Alqutaibi, Mohammed Ahmed Alghauli, Marwan Hamed Awad Aljohani, Muhammad Sohail Zafar, Advanced additive manufacturing in implant dentistry: 3D printing technologies, printable materials, current applications and future requirements, Bioprinting, Volume 42, 2024,

 

Alghauli M, Alqutaibi AY, Wille S, Kern M. 3D-printed versus conventionally milled zirconia for dental clinical applications: Trueness, precision, accuracy, biological and esthetic aspects. J Dent. 2024 May;144:104925. doi: 10.1016/j.jdent.2024.104925. Epub 2024 Mar 11. PMID: 38471580.

 

Gad MM, Al Mahfoudh HA, Al Mahfuth FA, Hashim KA, Khan SQ, Al-Qarni FD, Baba NZ, Al-Harbi FA. A comparative study of strength and surface properties of permanent 3D-printed resins with CAD-CAM milled fixed dental prostheses. J Prosthodont. 2024 Nov 20. doi: 10.1111/jopr.13990. Epub ahead of print. PMID: 39568135.

 

Alghauli MA, Almuzaini S, Aljohani R, Alqutaibi AY. Influence of 3D printing orientations on physico-mechanical properties and accuracy of additively manufactured dental ceramics. J Prosthodont Res. 2025 Jan 4. doi: 10.2186/jpr.JPR_D_24_00092. Epub ahead of print. PMID: 39756936.

Alghauli MA, Aljohani R, Almuzaini S, Aljohani W, Almutairi S, Alqutaibi AY. Accuracy, Marginal, and Internal Fit of Additively Manufactured Provisional Restorations and Prostheses Printed at Different Orientations. J Esthet Restor Dent. 2024 Nov 6. doi: 10.1111/jerd.13346. Epub ahead of print. PMID: 39503606.

 

 

The definition of additive manufacturing and the technologies should follow the ISO standards. Including all the technologies. Material jetting, binder jetting, material extruding, fused deposition modeling, bed powder fusion, and their derivatives.

The introduction feels as if it does not add to the reader’s knowledge, when it is so generic without real presentation of data, for example, in lines 54, and 55 “Ceramic crown composed of advanced ceramic materials; these crowns have become increasingly popular in restorative dentistry” and the paragraphs on resin, particularly line 65-67, and all other similar sentences. I don’t find these sentences necessary in a scientific paper and the same for many other sentences. Please remove any generic sentences and keep only those that present knowledge for the reader.

 

In the title, you made it clear that would talk about printable materials but there are no materials properties, composition, processing, or direct or indirect printing in the introduction.

 

“The use of 3D printing to produce definitive crowns has also been linked to higher patient satisfaction. Patients appreciate the ability to swiftly generate custom-fitted crowns that match the color and feel of their natural teeth [8]. Furthermore, the flexibility of 3D printing allows for simple alterations and modifications, ensuring that the final crown suits each patient's requirements [21]. This paragraph gives strong and solid conclusions, while the references are not even about dental permanent crowns, one study was on pediatric patients, and the other on orthopedic implantation! Please check your manuscript thoroughly. I am afraid it requires deep scanning, and rewriting, delving deeper into additive manufacturing technologies, and presenting only the scientific facts and data for the readers in a much attractive way.

 

Material and method

It is structured in a bit satisfying way. However, some paragraphs are mixed with the results, such as in the inclusion and exclusion criteria, you should not state how many studies were found in the literature and how many were included, because these are results!

Please refer to previous systematic or scoping reviews for a better and more wide vision.

 

You might need to number the subheadings of your sections.

 

Results

In the results section, the findings are very shallow, for example, mechanical properties are not well described, which kind of properties were tested in the original studies, and what are the numbers of such comparisons. This is true for all the results section.

Then when you are talking about polishing or fracture resistance or thermocycling you said “of dental crowns” What is the material of these crowns, acrylic, composite, varsiosmile, NextDent, Asiga, Zirconia, Lithium disilicate, Metal, PEEK?

 

I was so excited when I got to review this manuscript because the topic of 3D printing is very rich and extensive. I could not find any well-articulated and really obvious knowledge in this manuscript. Unfortunately, this review is far from complete and cannot be published in this form. I hope you will consider redoing the web research, including all studies, and rewriting your manuscript more scientifically.

 

You have done a lot, till this point, congratulations. However, I think you can formulate the manuscript again in a much better way,

Looking forward to reading your next version of the manuscript.

 

Kind regards

 

Author Response

General Major Issues:

Comment: The manuscript did not include all the additive manufacturing techniques and only concentrated on some daughter technologies and derivative technologies of the VAT photopolymerization. suggest that you add all the technologies according to the ISO classifications that could be used for the production of dental crowns. Those that cannot produce dental parts as sheet lamination can be mentioned only by name. Or less favorable option, you can change the title of your manuscript to “Additively fabricated permanent crown materials for vat photopolymerization technologies: An overview of the literature and update” and the content of your manuscript accordingly. I prefer the first option that you add more even if that took time, to enhance the impact of your article on the literature, particularly adding the last updates.

Response: Thank you for your comment. I totally agree with your comment and recommendations. This review focused on crown configuration (excluding all studies investigates specimens) which limit the included studies in relation the published articles. And according to search time, some articles are published after finalization of this review and bead on that we didn’t include. In term of technologies, only technologies of included studied were included with more clarification . I agreed with the first option you suggested and based on your recommendation, the review was reviewed and updated to some extent.

Comment: Another important matter is that 24 studies are very few for ceramic and resin crowns, there are tremendous studies numbers in the literature focusing on ceramic and resin crowns, to the best of my knowledge! I think you could have better insight into the literature if a second reviewer helped with the search strategy. I have never been able to execute a thorough review without the help of a second or a third reviewer.I took a fast blink to PubMed and I found that “Revilla-León” alone has more than 10 studies on printed crowns, and “Kim JS”, “Kim GM”, or “Kim HJ” and others from South Korea possess around 30 studies or more, and so on. Given that you talked about mechanical, physical properties, accuracy, and other properties, you should have found hundreds of papers on dental crowns or materials applied for printing ceramic and resin crowns.

Response: thank you for your comment. As I clarified in the response to the 1^st. comment and based on the inclusion and exclusion criteria, all articles not investigated crown are excluded. As no more literature about this point, this study was intended to point out the growing importance of additive technologies and materials used for permanent crown.  However, this point added to study limitation with further recommendations to conduct systematic review on the huge published articles in this new era. Please, see highlighted part in study limitations and recommendations 

 

Comment: The title of your review is focusing on the crown materials! Although the manuscript is not, you did not include material composition, solid loading, filler content, brands, processing, the impact of printing parameters, or postprocessing such as debinding, sintering, or postcuring. There is no data about the microstructure of the produced crowns, grains and their boundaries, and so on. Please add more or consider changing the title.

Response: Thank you for your comment. I totally agree with you. However, I Designed this review to be a starting point as no previous review figure out the importance of 3D permanent crown.  Other points were addressed in the study limitation and future recommendations.

Minor issues

Abstract

Comment: How many articles were found in each database, or in total, and how many studies are included?

Response: thank you for your comment. The total number found in databases and included studies added.

 

Comment: The abstract is more general speaking. It needs to be more focused on the subject of the manuscript, factors materials, famous technologies…etc.

Response: thank you for your valuable comment. The abstract was modified to be more focus in the study objective specially the results section. Please, see the highlighted part in abstract  

Comment: The keywords are also weak, this is your section, try to add important keywords so your manuscript will pop up in the research engine when the readers are looking for certain subjects.

Response: Thank you for your valuable suggestion. We agree that enhancing the keywords will improve the visibility of our manuscript in search engines. We have revised our keywords.

Introduction

Comment: The introduction is mainly so generic, resembling more of a magazine talk than a scientific paper. It needs only polishing of the English language, and to be more specific. For instance, when you say 3D printing is better than conventional approaches! So what are these conventional approaches, there are manual methods or metal casting, or manual methods with ceramic heat press, or partial digital workflow with milled wax and resin patterns, or CNC milled restorations through full digital or partial digital workflow.

I suggest that you concentrate your comparison against manual methods or CNC milling technology. In this way, the readers will know exactly what you are comparing.

Moreover, In which aspects are additive manufacturing technologies better? You have to name these aspects relying on previous studies or evidence-based projects.

Suggestions

Branco, A.C.; Colaço, R.; Figueiredo-Pina, C.G.; Serro, A.P. Recent Advances on 3D-Printed Zirconia-Based Dental Materials: A Review. Materials 2023, 16, 1860. https://doi.org/10.3390/ma16051860

Ahmed Yaseen Alqutaibi, Mohammed Ahmed Alghauli, Marwan Hamed Awad Aljohani, Muhammad Sohail Zafar, Advanced additive manufacturing in implant dentistry: 3D printing technologies, printable materials, current applications and future requirements, Bioprinting, Volume 42, 2024,

Alghauli M, Alqutaibi AY, Wille S, Kern M. 3D-printed versus conventionally milled zirconia for dental clinical applications: Trueness, precision, accuracy, biological and esthetic aspects. J Dent. 2024 May;144:104925. doi: 10.1016/j.jdent.2024.104925. Epub 2024 Mar 11. PMID: 38471580.

Gad MM, Al Mahfoudh HA, Al Mahfuth FA, Hashim KA, Khan SQ, Al-Qarni FD, Baba NZ, Al-Harbi FA. A comparative study of strength and surface properties of permanent 3D-printed resins with CAD-CAM milled fixed dental prostheses. J Prosthodont. 2024 Nov 20. doi: 10.1111/jopr.13990. Epub ahead of print. PMID: 39568135

Alghauli MA, Almuzaini S, Aljohani R, Alqutaibi AY. Influence of 3D printing orientations on physico-mechanical properties and accuracy of additively manufactured dental ceramics. J Prosthodont Res. 2025 Jan 4. doi: 10.2186/jpr.JPR_D_24_00092. Epub ahead of print. PMID: 39756936.

Alghauli MA, Aljohani R, Almuzaini S, Aljohani W, Almutairi S, Alqutaibi AY. Accuracy, Marginal, and Internal Fit of Additively Manufactured Provisional Restorations and Prostheses Printed at Different Orientations. J Esthet Restor Dent. 2024 Nov 6. doi: 10.1111/jerd.13346. Epub ahead of print. PMID: 39503606.

Response: Thank you for your comments and suggestions. The manuscript was rephrased and modifications of issue like this were done through the text. One paragraph added clarifying the additive technologies in comparison with other methods and suggested references are cited.  

Comment: The definition of additive manufacturing and the technologies should follow the ISO standards. Including all the technologies. Material jetting, binder jetting, material extruding, fused deposition modeling, bed powder fusion, and their derivatives.

The introduction feels as if it does not add to the reader’s knowledge, when it is so generic without real presentation of data, for example, in lines 54, and 55 “Ceramic crown composed of advanced ceramic materials; these crowns have become increasingly popular in restorative dentistry” and the paragraphs on resin, particularly line 65-67, and all other similar sentences. I don’t find these sentences necessary in a scientific paper and the same for many other sentences. Please remove any generic sentences and keep only those that present knowledge for the reader.

Response: Thank you for your comment.

 

Comment: In the title,

you made it clear that would talk about printable materials but there are no materials properties, composition, processing, or direct or indirect printing in the introduction.

Response: thank you for your comment. In introduction I focused on the printing technologies and their advance in permanent crown fabrication and postponed all related material composition and properties to the results section to avoid information repetition. 

Comment: “The use of 3D printing to produce definitive crowns has also been linked to higher patient satisfaction. Patients appreciate the ability to swiftly generate custom-fitted crowns that match the color and feel of their natural teeth [8].

 Furthermore, the flexibility of 3D printing allows for simple alterations and modifications, ensuring that the final crown suits each patient's requirements [21].

This paragraph gives strong and solid conclusions, while the references are not even about dental permanent crowns, one study was on pediatric patients, and the other on orthopedic implantation!

Please check your manuscript thoroughly. I am afraid it requires deep scanning, and rewriting, delving deeper into additive manufacturing technologies, and presenting only the scientific facts and data for the readers in a much attractive way.

Response: Thank you for your comment and valuable suggestions. The manuscript was revised and modified accordingly.

 

Material and method

Comment: It is structured in a bit satisfying way. However, some paragraphs are mixed with the results, such as in the inclusion and exclusion criteria, you should not state how many studies were found in the literature and how many were included, because these are results!

Please refer to previous systematic or scoping reviews for a better and more wide vision.

You might need to number the subheadings of your sections.

Response: thank you for your valuable notes and recommendations. The method section was revised and all parts related to results moved from methods to results section. Also subheadings modifications and numbering was done accordingly.

 

Results

Comments: In the results section, the findings are very shallow, for example, mechanical properties are not well described, which kind of properties were tested in the original studies, and what are the numbers of such comparisons. This is true for all the results section.

Then when you are talking about polishing or fracture resistance or thermocycling you said “of dental crowns” What is the material of these crowns, acrylic, composite, varsiosmile, NextDent, Asiga, Zirconia, Lithium disilicate, Metal, PEEK?

 Response: Thank you for your comment. More details about materials type added.

 

Comment: I was so excited when I got to review this manuscript because the topic of 3D printing is very rich and extensive. I could not find any well-articulated and really obvious knowledge in this manuscript. Unfortunately, this review is far from complete and cannot be published in this form. I hope you will consider redoing the web research, including all studies, and rewriting your manuscript more scientifically.

Response: Thank you for your comment. According to review design, this review focus on an overview of 3D printed materials for crown fabrication. Based on the comment and recommendations, more search to update this review was done and completed hopefully all modifications and responses meet the required criteria.

 

Comment: You have done a lot, till this point, congratulations. However, I think you can formulate the manuscript again in a much better way,

Looking forward to reading your next version of the manuscript.

 

Response: I appreciated your comments and recommendations which added and improved the quality of review.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

This paper is a review of the production of permanent crowns using 3D printing technology.

The importance of the topic

• 3D 프린팅 기술의 발전과 그 적용 가능성에 대한 논의는 매우 시의적절하고 중요한 주제입니다. 저는 이 논문의 내용이 기술적으로나 임상적으로나 의미 있는 연구라고 믿습니다.
•  
• 연구 목적 및 범위

• The purpose of this review is to “collect and evaluate information on the fabrication of 3D printed permanent crowns,” which shows that the research objective is clear and that a review of the field has been conducted.

• The scope of the study can be said to be specific in that only 24 relevant papers were included after searching 123 articles using various search engines.

Structure and logical flow

The development and content of the paper are also logically structured based on format

Explain the purpose of the study, mention the methods, and then present the results and their interpretation. The conclusion clearly suggests which technique is more appropriate and which further research is needed.

Data and Research Methods

The searched data and research methods appear to have no reliability issues. The research was conducted using databases (Scopus, PubMed, Google Scholar), and the method of selecting and evaluating 24 papers can be said to be systematic.

Research Results

• Technical classification: The section that breaks down 3D printing technologies into categories such as “digital light processing (DLP),” “stereolithography (SLA),” and “photochemical ceramic manufacturing (LCM)” is very useful.
• 기술 성능 비교: 세라믹 기반 크라운과 수지 기반 크라운을 비교한 결과 세라믹 기반 크라운이 더 나은 성능을 발휘한다는 결론을 내린 것은 중요한 결과입니다. 그러나 수지 기반 크라운이 임상적으로 허용 가능하다고 언급된 부분은 현재 기술적 한계가 있지만, 향후 연구 방향을 제시하는 데 도움이 될 수 있습니다.

Conclusion and Future Research Suggestions

• The conclusion suggests a direction for future research by suggesting that “ceramic-based crowns can be recommended as permanent crowns, and resin-based crowns require further study.” This is a meaningful conclusion that can serve as an important guideline for future researchers.

Writing style and clarity

• The sentences were written concisely and clearly. The main objectives and results of the study were easy to understand.

Technical depth and expertise

• An understanding of 3D printing technology and permanent crown fabrication is required, and the content covered in the text is professional and in-depth. However, it would have been better if more specific experimental results or data were included.

Review comments

• This paper can be evaluated as a clear, logical, and systematic paper overall. The purpose, method, results, and conclusion of the study are connected without difficulty. It can be evaluated as a useful review paper because it presents a comprehensive evaluation and content on the important topic of permanent crown production using 3D printing. However, I think it would have been a good review study if the review had included more specific experimental results or data.

Author Response

Comment: This paper is a review of the production of permanent crowns using 3D printing technology.

The importance of the topic

• 3D 프린팅 기술의 발전과 그 적용 가능성에 대한 논의는 매우 시의적절하고 중요한 주제입니다. 저는 이 논문의 내용이 기술적으로나 임상적으로나 의미 있는 연구라고 믿습니다.
• 연구 목적 및 범위
• The purpose of this review is to “collect and evaluate information on the fabrication of 3D printed permanent crowns,” which shows that the research objective is clear and that a review of the field has been conducted.
• The scope of the study can be said to be specific in that only 24 relevant papers were included after searching 123 articles using various search engines.

Response: Thank you for your review. The scope of the study is updated as per suggestions in line 145-146.

Structure and logical flow

The development and content of the paper are also logically structured based on format

Explain the purpose of the study, mention the methods, and then present the results and their interpretation. The conclusion clearly suggests which technique is more appropriate and which further research is needed.

Response: Thank you for your review.

Data and Research Methods

The searched data and research methods appear to have no reliability issues. The research was conducted using databases (Scopus, PubMed, Google Scholar), and the method of selecting and evaluating 24 papers can be said to be systematic.

Research Results

• Technical classification: The section that breaks down 3D printing technologies into categories such as “digital light processing (DLP),” “stereolithography (SLA),” and “photochemical ceramic manufacturing (LCM)” is very useful.

Response: Thank you.

• 기술 성능 비교: 세라믹 기반 크라운과 수지 기반 크라운을 비교한 결과 세라믹 기반 크라운이 더 나은 성능을 발휘한다는 결론을 내린 것은 중요한 결과입니다. 그러나 수지 기반 크라운이 임상적으로 허용 가능하다고 언급된 부분은 현재 기술적 한계가 있지만, 향후 연구 방향을 제시하는 데 도움이 될 수 있습니다.

Response: Thank you

 

 

Conclusion and Future Research Suggestions

• The conclusion suggests a direction for future research by suggesting that “ceramic-based crowns can be recommended as permanent crowns, and resin-based crowns require further study.” This is a meaningful conclusion that can serve as an important guideline for future researchers.

Response: Thank you for your positive feedback.

Writing style and clarity

• The sentences were written concisely and clearly. The main objectives and results of the study were easy to understand.

• Response: Thank you for your positive feedback.

Technical depth and expertise

• An understanding of 3D printing technology and permanent crown fabrication is required, and the content covered in the text is professional and in-depth. However, it would have been better if more specific experimental results or data were included.

Response: Thank you for your valuable comment. some data added to manuscript and highlighted in yellow.

 

Review comments

• This paper can be evaluated as a clear, logical, and systematic paper overall. The purpose, method, results, and conclusion of the study are connected without difficulty. It can be evaluated as a useful review paper because it presents a comprehensive evaluation and content on the important topic of permanent crown production using 3D printing. However, I think it would have been a good review study if the review had included more specific experimental results or data.

 

Response: Thank you for your valuable comment. some data added to manuscript and highlighted in yellow.

Reviewer 3 Report

Comments and Suggestions for Authors

Dear respected author,

In my previous review I had a comment that there is no way that the original articles are limited to 24 that studies crowns of zirconia, glass ceramic, resins and metal, they should be more than 100, as I took a look to PubMed.

The source of data included in this review might not be enough to write a review eve for narrative none.

Kind regards

Author Response

Dear respected author,

In my previous review I had a comment that there is no way that the original articles are limited to 24 that studies crowns of zirconia, glass ceramic, resins and metal, they should be more than 100, as I took a look to PubMed.

The source of data included in this review might not be enough to write a review eve for narrative none.

Kind regards

 

Response: Thank you for your valuable comment. We appreciate your approach in considering a broader review that includes all crown materials. Perhaps we did not clarify our response adequately in the first round. The objective of this review was to focus exclusively on 3D-printed permanent crowns in their real crown configuration, rather than specimen-based studies (e.g., bar-shaped or disc samples). Although our search yielded many articles based on the selected keywords, many were excluded due to specific inclusion criteria. Studies on conventionally fabricated and CAD-CAM milled crowns were not included, significantly reducing the number of eligible studies. Additionally, only research on permanent crowns was considered, while those focusing on temporary or provisional crowns were excluded. Furthermore, experimental studies conducted on non-crown specimens were also removed from consideration. These strict criteria resulted in a final selection of 24 relevant studies. We acknowledge that a broader review incorporating all fabrication techniques, and a wider range of materials would provide additional insights, and we sincerely appreciate your suggestion. We will consider expanding our scope in a future follow-up review to include these aspects. We hope this explanation clarifies our selection process and the rationale behind the number of included studies. Thank you again for your thoughtful feedback.