Volumetric and Linear Adaptation of an Indirect Adhesive Restoration: Comparison of Chairside 3D Printing and Milling Techniques

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study titled “Volumetric and linear adaptation of an indirect adhesive restoration: comparison of chairside 3D printing and milling techniques” aimed to evaluate volumetric and linear adaptation of an indirect adhesive restoration, comparing a novel chairside 3D printer to conventional milling techniques

The study compared different techniques: chairside 3D printing vs. chairside milling vs. industrial milling machine, that were used to fabricated indirect adhesive restorations from different materials: polymer-filled hybrid ceramic and ceramic-filled hybrid composite.

The study is interesting, however some issues must be addressed:

Abbreviation explanation of CAD/CAM should be revised.

In Material and Methods please clearly mention what material was used in each study group.

In Table 1 and throughout the text correct the brand name of the material (Irix® Max).

Discussion is too brief and must be enhanced.

Line 240, explain the abbreviation “OCT” at its first use.

The issue of mechanical properties of the tested materials should be briefly discussed, as well as the limitations in materials used in each CAM method.

Conclusions should be revised to omit bullet points.

In point #3 can be hardly derived from the results of the current study, as only one type of each CAM method was compared. Also, please omit references in conclusions. This statement could be well transferred to Discussion section.

In point #4 there is a bit of overstatement, since the materials that were used (or that could be used) for AM and CNC are quite different in terms of mechanical strength, hence not in every clinical case composite adhesive restoration can be used interchangeably with the milled one, e.g. made of zirconia ceramics.

Please rephrase the statement in lines 307-308.

 

Some editorial issues must be fixed:

Type of paper is not provided.

Affiliation of authors from the same Uni is repeated unnecessarily.

Remove headings from the Abstract

Table’s caption should be placed above the tables, not below.

Use period as a decimal separator, instead of comma in table 2

Remove “3.1 Subsection” from line 230.

Remove double spacings throughout the text.

References list has double numbering.

Comments on the Quality of English Language

English language style needs correction to more formal/scientific at times.

Author Response

Reviewer #1

Comment#1: Abbreviation explanation of CAD/CAM should be revised.

Response#1: Thanks for the comment, the explanation has been revised properly

Comment #2: In Material and Methods please clearly mention what material was used in each study group.

Response#2: Thanks for the comment, the section was accordingly modified

Comment #3: In Table 1 and throughout the text correct the brand name of the material (Irix® Max).

Response#3: Thanks for the comment, the text was accordingly modified

Comment #4: Discussion is too brief and must be enhanced.

Response#4: Discussion was improved, with particular focus on the limitations of the study.

Comment #5: Line 240, explain the abbreviation “OCT” at its first use.

Response#5: Thanks for the comment, the text was accordingly modified

Comment #6: The issue of mechanical properties of the tested materials should be briefly discussed, as well as the limitations in materials used in each CAM method.

Response#6: A dedicated paragraph was added in M&M section. “Irix® Max  was selected for this study since it was developed by same producer of the milling unit, thus avoiding issues and biases related to optimization of the fabrication process. Vita Enamic on the other hand, was selected due to the high amount of litera-ture related to it. Moreover, both materials are considered hybrid ceramics, thus further studies on mechanical aspects could benefit of this selection.”

Comment #7: Conclusions should be revised to omit bullet points.

Response#7: Thanks for the comment, the conclusion section has been rewritten and bullet points has been removed.

Comment #8: In point #3 can be hardly derived from the results of the current study, as only one type of each CAM method was compared. Also, please omit references in conclusions. This statement could be well transferred to Discussion section.

Response#8: Authors agree with this comment, conclusions were rewritten and limitations were moved in discussion section.

Comment #9: In point #4 there is a bit of overstatement, since the materials that were used (or that could be used) for AM and CNC are quite different in terms of mechanical strength, hence not in every clinical case composite adhesive restoration can be used interchangeably with the milled one, e.g. made of zirconia ceramics.

Response#9: Authors agree with the comment, conclusions were rewritten to highlight the importance of mechanical aspects.

Comment #10: Please rephrase the statement in lines 307-308.

Response#10: Unfortunately, we were unable to find the lines cited in the comment, probably due to changes in the text according to other comments of the reviewers. Please do not hesitate to contact us for further clarification if needed.

Type of paper is not provided.

Type of the Paper is provided in the heading of the article and the submission process: Article for Topical Advisory Panel Members

Affiliation of authors from the same Uni is repeated unnecessarily.

Unfortunately, this aspect is unclear. Affiliation were reported to allow inserting e-mails according to template, should we remove them all and keep a single affiliation for all authors?

Remove headings from the Abstract

Thanks for the comment, all headings were removed from the abstract

Table’s caption should be placed above the tables, not below.

Thanks for the comment, captions were moved above tables and figures.

Use period as a decimal separator, instead of comma in table 2

Thanks for the comment, table 2 was updated

Remove “3.1 Subsection” from line 230.

Thanks for the comment, the text was removed.

Remove double spacings throughout the text.

Thanks for the comment, double spacing was removed.

References list has double numbering.

Thanks for the comment, double numbering was removed.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Review

Journal Applied Sciences (ISSN 2076-3417)

Manuscript ID applsci-3405008

Type Article

Title Volumetric and linear adaptation of an indirect adhesive restoration: comparison of chairside 3D printing and milling techniques.

Authors Andrea Baldi , Tommaso Rossi , Ilaria Stura , Allegra Comba , Maur Fazioni , Chiara Rolando , Giorgio Ferrero , Paola Ceruti , Nicola Scotti *

Section Applied Dentistry and Oral Sciences

 

   This paper proposes a study evaluating the linear volumetric and interfacial adaptation of an indirect adhesive restoration fabricated by chairside CNC (subtractive computer numerically controlled (CNC) milling ) machining and a novel chairside 3D printer using micro-computed tomography (micro-CT).

   The authors conclude that

 1- The chosen CAM method can significantly influence the volumetric and linear interfacial adaptation.

2. The difference comes from the internal adaptation between the groups.

3. The disparity of the published results between 3D printing machines and milling units, prevent direct comparisons between studies.

4. The authors express their preference for AM (additive manufacturing)

  technology, faster and cheaper than CNC milling.(Lim et all, 2023) (Balestra et all, 2024) (Peskersoy et all, 2024).

 

    Historically, if the printing parameters are respected with particular care given to the post-processing procedures, the additive manufacturing technique proves to be more efficient than the milling technique. The explanation comes indeed, the milling technique has shown limitations due to the dimensions of the burs. Thus the tooth design is less precise and marginal defects explain this lower performance. Suksuphan, P.; Krajangta, N.; Didron, P.P.; Wasanapiarnpong, T.; Rakmanee, T. Marginal Adaptation and Fracture Resistance of

Milled and 3D-Printed CAD/CAM Hybrid Dental Crown Materials with Various Occlusal Thicknesses. J. Prosthodont. Res. 2023.

 

The article should emphasize that the 3D printing technique can still be improved at different levels. These improvements concern the search for the printing angle, the evaluation of the thickness of the printing layer, the improvement of the curing procedures during and after printing, the search for the ideal 3D printing resin but also and above all the process of surface preparation.

  The article does not address any particular aspect of these fixed achievements. Indeed, aging and microbial colonization are not mentioned. However, in the long term, it seems that microbial plaque colonizes more easily materials made by printing multiple layers compared to those made by machining.

 

   The article must be accompanied by the usual reservations, concerning the in vivo application of these results. Indeed, the study only concerns a single premolar after extraction, the bonding is carried out without relation to the intraoral conditions. The implementation of different techniques with different materials, makes it difficult to attribute the best result to one or another process? This is all the more so since all the results obtained, on reduced samples, remain acceptable. In these conditions, other investigations are necessary in vivo.

 

 

 Add bibliography… recent  (2023-2024)

Lim YA, Kim JM, Choi Y, Park S. Evaluation of Fitness and Accuracy of Milled and Three-Dimensionally Printed Inlays. Eur J Dent. 2023 Oct;17(4):1029-1036. doi: 10.1055/s-0042-1758796. Epub 2023 Jan 4. PMID: 36599450; PMCID: PMC10756847.

 Balestra D, Lowther M, Goracci C, Mandurino M, Cortili S, Paolone G, Louca C, Vichi A. 3D Printed Materials for Permanent Restorations in Indirect Restorative and Prosthetic Dentistry: A Critical Review of the Literature. Materials (Basel). 2024 Mar 18;17(6):1380. doi: 10.3390/ma17061380. PMID: 38541534; PMCID: PMC10971886.

Peskersoy C, Oguzhan A. Evaluation of the Mechanical and Adhesion Characteristics of Indirect Restorations Manufactured with Three-Dimensional Printing. Polymers (Basel). 2024 Feb 23;16(5):613. doi: 10.3390/polym16050613. PMID: 38475296; PMCID: PMC10934380.

Vargas-Corral FG, Vargas-Corral AE, Rodríguez-Valverde MA, Bravo M, Rosales-Leal JI. Clinical comparison of marginal fit of ceramic inlays between digital and conventional impressions. J Adv Prosthodont. 2024 Feb;16(1):57-65. doi: 10.4047/jap.2024.16.1.57. Epub 2024 Feb 23. PMID: 38455677; PMCID: PMC10917630.

Comments for author File: Comments.pdf

Author Response

Reviewer #2

Historically, if the printing parameters are respected with particular care given to the post-processing procedures, the additive manufacturing technique proves to be more efficient than the milling technique. The explanation comes indeed, the milling technique has shown limitations due to the dimensions of the burs. Thus the tooth design is less precise and marginal defects explain this lower performance. Suksuphan, P.; Krajangta, N.; Didron, P.P.; Wasanapiarnpong, T.; Rakmanee, T. Marginal Adaptation and Fracture Resistance of

Milled and 3D-Printed CAD/CAM Hybrid Dental Crown Materials with Various Occlusal Thicknesses. J. Prosthodont. Res. 2023.

Authors completely agree with this aspect. Cited reference was added in the text. 

 

The article should emphasize that the 3D printing technique can still be improved at different levels. These improvements concern the search for the printing angle, the evaluation of the thickness of the printing layer, the improvement of the curing procedures during and after printing, the search for the ideal 3D printing resin but also and above all the process of surface preparation.

Authors completely agree with these aspects. A dedicated paragraph was added in the discussion section.

 

  The article does not address any particular aspect of these fixed achievements. Indeed, aging and microbial colonization are not mentioned. However, in the long term, it seems that microbial plaque colonizes more easily materials made by printing multiple layers compared to those made by machining.

Authors thanks for the comment. The biological aspects are surely critical, as well as the mechanical aspects. Both of them were not part of the present protocol, but will be included in further developments. A dedicated sentence was inserted in the discussion, to highlight limitations of the present study.

 

   The article must be accompanied by the usual reservations, concerning the in vivo application of these results. Indeed, the study only concerns a single premolar after extraction, the bonding is carried out without relation to the intraoral conditions. The implementation of different techniques with different materials, makes it difficult to attribute the best result to one or another process? This is all the more so since all the results obtained, on reduced samples, remain acceptable. In these conditions, other investigations are necessary in vivo.

 Authors thanks for the comment. It is important to highlight that it’s very premature to give in-vivo indications for such materials, before doing mechanical and biological tests. This was specified both in discussion and conclusion sections. 

Add recent bibliography (2023-2024)

Authors thanks for the precious contribution in suggesting different papers. Citations were added in the manuscript.

 

Author Response File: Author Response.pdf