Biomechanical Rationale for a Novel Implant Design Reducing Stress on Buccal Bone
Round 1
Reviewer 1 Report
I think the study is very interesting. A new gentle concept was presented and I think it is worth investigating in depth.
1) The introduction lacks a bit of reference to the general medical history of the patients, because of course the previous illnesses, if any, play a huge role. I think it makes sense to mention this briefly.
2) What is no entirely clear from the introduction is whether the excessive insertion torque leads to the same bone remodelling and bone loss in the upper and lower jaws or whether there are differences.
3) How many people have placed the implants and what is their experience? (If more than one person did the study, it can be possible to calculate ICC (Intraclass Correlation Coefficient)).
4) There is also no clear distribution of how many implants were in the control group and in the test group.
5) How did you decide to take the mean values? It is missing if you did a test for normal distribution.
6) In the results it says that more time was needed to place the AlfaGate implants. How big was the difference? You can also briefly add it to the discussion and discuss the relevance of this difference.
It would be interesting and useful for a future study to adapt the polyurethane blocks to the anatomy of the maxilla and mandible.
Author Response
Reviewer #1
I think the study is very interesting. A new gentle concept was presented and I think it is worth investigating in depth.
1) The introduction lacks a bit of reference to the general medical history of the patients, because of course the previous illnesses, if any, play a huge role. I think it makes sense to mention this briefly.
RE: We agree with the reviewer and have added two new references (Jiang et al. 2021; Chen et al. 2013)
2) What is no entirely clear from the introduction is whether the excessive insertion torque leads to the same bone remodelling and bone loss in the upper and lower jaws or whether there are differences.
RE: One might indeed expect higher stress (and hence more remodelling) in the mandible due to its greater percentage of cortical bone. Of course it is complicated to honestly evaluate the effect of insertion stress as man co-factors such as loading scenario and restoration type come into play. We have added an additional reference (Kern et al. 2016) which seemed relevant
3) How many people have placed the implants and what is their experience? (If more than one person did the study, it can be possible to calculate ICC (Intraclass Correlation Coefficient)).
RE: We have added that one single operator placed all implants which may be seen as a limitation; this was done for standardization purposes
4) There is also no clear distribution of how many implants were in the control group and in the test group.
RE: It has been added more explicitly that sample size was 10 implants per group
5) How did you decide to take the mean values? It is missing if you did a test for normal distribution.
RE: Given the difference in curve lengths (i.e. time needed for implant insertion) this was the sole approach deemed feasible for comparing the two implant types. Given that the measurement values were influenced by numerous physical parameters, they were considered as being normally distributed according to the central limit theorem. This has been added to Materials and Methods.
6) In the results it says that more time was needed to place the AlfaGate implants. How big was the difference? You can also briefly add it to the discussion and discuss the relevance of this difference.
RE: It has been added to the discussion section that approx. 30% more time was needed for placing an AG implant. Given that smaller osteotomy diameters are sufficient for placing an AG implant this potential disadvantage will be overcompensated by skipping a drill step.
It would be interesting and useful for a future study to adapt the polyurethane blocks to the anatomy of the maxilla and mandible.
The reviewer is correct and this has been added to the discussion section as a limitation of the study performed
Author Response File: 
Author Response.pdf
Reviewer 2 Report
1. Authors need to justify for the selection of implants. Why they chose those implants for study.
2. Abstract should be elaborated more with proper conclusion
3. Authors need to explain rationale of use of evaluation methods in the current study (include studies)
4. Authors should explain regarding use of Periotest instead of RFA? (Include studies)
5. Authors should explain validity of use of insertion torque. (Include studies)
6. Authors should elaborate relationship of microcracks and bone resorption. (Include studies)
7. More figures are needed.
8. Explain more about microcracks with immediate and conventional loading. (Include studies)
9. Authors should explain the relationship of bone strain and resorption and include studies as well as relate to the current study.
10. Current study needs to explain how Alfagate implant is better than BLT as final insertion torque is better & statistically significant in BLT. Meaning although strain is low but final torque is also low and correlate with question no.8 (table 2)
11. Line No. 156-159 need to elaborated and substantiated.
12. Elaborate more about statistical methods and validity of sample size.
13. Correlate periotest and insertion torque withs studies. (Line no. 134-135)
14. Substantiate with more studies for usage of polyurethane foam blocks.( line no.183-185)
15. Plagiarism is high around 31%, kindly try to reduce to a minimum as per the journal policy (iThenticate Report attached).
Comments for author File: Comments.pdf
Author Response
Reviewer #2
- Authors need to justify for the selection of implants. Why they chose those implants for study.
RE: It has been added to the discussion that a myriad of implant systems could have served as control groups. Straumann BLT has been chosen at is widely known and used.
- Abstract should be elaborated more with proper conclusion
RE: We fully agree with the reviewer but as per guidelines the Abstract should be about 200 words maximum and we already had 239 words in the original version and did some minor rewording.
- Authors need to explain rationale of use of evaluation methods in the current study (include studies)
RE: We have introduced the methodology in previous studies (original References 22-24) and more explicitly refer to these papers. Please also note that the iThenticate report lists exactly these predecessors from my group.
- Authors should explain regarding use of Periotest instead of RFA? (Include studies)
RE: As the AG implant used here is a new implant which is not yet on the market, neither SmartPegs nor MultiPegs were available and Periotest was the only option for determining primary stability. We have added the publication by Akkoyun et al. 2022 who faced the same issue but with individual root-analog implants.
- Authors should explain validity of use of insertion torque. (Include studies)
RE: A myriad of publications is available in this field and we have now mentioned Bandela et al. 2022 as well as previous work from our group (Winter et al. 2010) and further emphasized a review published by our group (Ikar et al.2020)
- Authors should elaborate relationship of microcracks and bone resorption. (Include studies)
RE: We have added references Tian et al.2022 and Abrahamsson et al. 2021 showing this relationship in animal models.
- More figures are needed.
RE: We have added a new figure showing the insertion of a BLT implant; If additional figures are needed for understanding this study, please specify.
- Explain more about microcracks with immediate and conventional loading. (Include studies)
RE: To the best of our knowledge, no studies are available clearly addressing this question. In addition to our own review (Ikar et al. 2020) we have added a paper by Mehl et al. 2013 but these data have to be interpreted very cautiously!
- Authors should explain the relationship of bone strain and resorption and include studies as well as relate to the current study.
RE: We have addressed this topic reviewing available literature in Ikar et al. 2022 and we have now referred to this paper several times.
- Current study needs to explain how Alfagate implant is better than BLT as final insertion torque is better & statistically significant in BLT. Meaning although strain is low but final torque is also low and correlate with question no.8 (table 2)
RE: Insertion torque is nothing but a surrogate measure of friction between implant and bone i.e. when high torques are needed for inserting an implant, considerable bone compression occurs. This however des not necessarily mean that great stability is obtained as the implant may only have contact with cortical bone (as is the case in tapered BLT implants). The new implant engages bone on the whole length of its body but due to the bulky area in the middle does not compress stiff, cortical bone extensively. We tried to further elaborate on this aspect in the discussion
- Line No. 156-159 need to elaborated and substantiated.
RE: We agree that this sentence was confusing in its original version. We have reworded to make clear that with the AG implant primary stability could be achieved comparable with BLT implants and as such AG implants should also be clinically applicable given the track record of BLT implants.
- Elaborate more about statistical methods and validity of sample size.
RE: Please see comment to reviewer #1 on statistical methods. Previous studies have been performed with the same sample size (n=10) which in the current case was limited due to the fabrication of the new implant type.
- Correlate periotest and insertion torque withs studies. (Line no. 134-135)
RE: See publication by Bandela et al. 2022 in combination with Winter et al. 2010
- Substantiate with more studies for usage of polyurethane foam blocks.( line no.183-185)
RE: Sawbones are indeed the material most widely used for such studies and in addition to the already cited references:
Gehrke SA, Pérez-Díaz L, Mazón P, De Aza PN. Biomechanical Effects of a New Macrogeometry Design of Dental Implants: An In Vitro Experimental Analysis. J Funct Biomater. 2019 Oct 25;10(4):47.
Dard M, Kuehne S, Obrecht M, Grandin M, Helfenstein J, Pippenger BE. Integrative Performance Analysis of a Novel Bone Level Tapered Implant. Adv Dent Res. 2016 Mar;28(1):28-33.
Wang R, Eppell SJ, Nguyen C, Morris N. Relative Contribution of Trabecular and Cortical Bone to Primary Implant Stability: An In Vitro Model Study. J Oral Implantol 2016;42:145-152.
Elias CN, Rocha FA, Nascimento AL, Coelho PG. Influence of implant shape, surface morphology, surgical technique and bone quality on the primary stability of dental implants. J Mech Behav Biomed Mater 2012;16:169-180.
We have added these new references:
Sierra-Rebolledo A, Allais-Leon M, Maurette-OʼBrien P, Gay-Escoda C. Primary Apical Stability of Tapered Implants Through Reduction of Final Drilling Dimensions in Different Bone Density Models: A Biomechanical Study. Implant Dent 2016;25:775-782.
Di Stefano DA, Arosio P, Gastaldi G, Gherlone E. The insertion torque-depth curve integral as a measure of implant primary stability: An in vitro study on polyurethane foam blocks. J Prosthet Dent 2018;120:706-714.
Wang TM, Lee MS, Wang JS, Lin LD. The effect of implant design and bone quality on insertion torque, resonance frequency analysis, and insertion energy during implant placement in low or low- to medium-density bone. Int J Prosthodont 2015;28:40-47.
Ueno D, Nakamura K, Kojima K, Toyoshima T, Tanaka H, Ueda K, Koyano K, Kodama T. A stepwise under-prepared osteotomy technique improves primary stability in shallow-placed implants: a preliminary study for simultaneous vertical ridge augmentation. Odontology 2018;106:187-193.
- Plagiarism is high around 31%, kindly try to reduce to a minimum as per the journal policy (iThenticate Report attached).
Thank you very much for checking this aspect! As previously mentioned, we are mostly referring to our own previous work which used an identical set up. For increasing readability, we did not simply refer to the methods established in these papers but added the relevant sections to this manuscript. We tried to reword as much as possible.
Author Response File: Author Response.pdf
