The Impact of Different Implant Approaches in Overdenture Rehabilitated Diabetic Patients: A Two-Year Follow-Up

Round 1

Reviewer 1 Report (New Reviewer)

Comments and Suggestions for Authors

The study assessed the effect of two different implant methodologies on peri-implant parameters in patients with type 2 diabetes mellitus. The test group resulted in reduced bone remodeling and better clinical conditions, with lower levels of pro-inflammatory cytokines at 24 months compared to the control group. The paper is well-written and technically sound. However, I recommend minor revisions to this paper for acceptance. My recommendations are as follows:

1. In Table 1, the test and control groups had identical baseline values across all parameters. Was the same group of participants used for both the test and control groups?

2. Table 2 shows no significant difference in HbA1c and FPG levels between the two groups. However, to ensure the validity of the results, the authors should consider evaluating potential differences in medication, food consumption, and lifestyle factors between the two groups of patients, which could have influenced the experimental outcomes.

3. To better illustrate the results in Table 5, it is helpful for the authors to consider presenting the data on pro-inflammatory cytokines and anti-inflammatory cytokines in separate tables or figures. 

4. Table 5 indicates that there were no significant changes observed after 12 months of implantation in either group. It is helpful for the authors to provide an explanation for this lack of significant change in their discussion.

5. As a limitation of the study, the authors should further discuss the generalizability of their findings to other populations, as the ethnicities of the participants were not reported in the paper, and the participants had a mean age of 66 and did not demonstrate improvement in their diabetes during the course of the study.

Comments on the Quality of English Language

Overall, the paper is well-written.

Author Response

Reviewer 1

 

The study assessed the effect of two different implant methodologies on peri-implant parameters in patients with type 2 diabetes mellitus. The test group resulted in reduced bone remodeling and better clinical conditions, with lower levels of pro-inflammatory cytokines at 24 months compared to the control group. The paper is well-written and technically sound. However, I recommend minor revisions to this paper for acceptance. My recommendations are as follows:

 

1. In Table 1, the test and control groups had identical baseline values across all parameters. Was the same group of participants used for both the test and control groups?

The authors thank the reviewer considerations. As the study followed the split-mouth design, each patient received two dental implants used to retain the rehabilitation were randomly assigned through a computer-generated list. This way, the values from baseline are the same for the evaluated parameters.

 

2. Table 2 shows no significant difference in HbA1c and FPG levels between the two groups. However, to ensure the validity of the results, the authors should consider evaluating potential differences in medication, food consumption, and lifestyle factors between the two groups of patients, which could have influenced the experimental outcomes.

The authors agree and thank the reviewer observation. We will keep this suggestion for a next study in this research line.

3. To better illustrate the results in Table 5, it is helpful for the authors to consider presenting the data on pro-inflammatory cytokines and anti-inflammatory cytokines in separate tables or figures.

The authors edited the table using different colors for pro- and anti-inflammatory markers.

 

4. Table 5 indicates that there were no significant changes observed after 12 months of implantation in either group. It is helpful for the authors to provide an explanation for this lack of significant change in their discussion.

Actually, intra-group analysis revealed that control implants presented higher levels IL-17, IL-21, IL-6 and TNF-α were recorded in control implants at 24 months when compared to 12 months (p<0.05), whereas lower levels of IL-10, IL-33 and TNF-α were observed at 24 months when compared to 12 months in test implants (p<0.05). The authors discussed this finding as follows bellow:

Even though the clinical data obtained during this investigation suggest, in general, a low percentage of peri-implant inflammation sites in both implant groups, it could be speculated that control group present an at-risk-for-harm condition due to the pro-inflammatory pattern of local molecules observed and this condition could predispose to peri-implantitis [31]. This disturbance in local levels of pro-inflammatory mediators in implants with an external hexagonal and standard connection seems to be exacerbated with time, since in this trial control implants showed higher levels of pro-inflammatory molecules IL-17, IL-33, IL-21, IL-23, IL-6 and TNF-α at 24 months in comparison with baseline (p<0.05). Furthermore, IL-17, IL-21, IL-6 and TNF-α were up-regulated at 24 months in control implants in comparison with 12 months (p<0.05). Importantly, previous data confirm that the peri-implant fluid augmented presence of IL-6 and IL-33 in intensifies the local inflammatory process, contributing to the risk of peri-implantitis [32,33]. Accordingly, it was observed a significantly positive association between IL-6 levels in the saliva and peri-implant disease [34]. Another important pro-inflammatory marker that was up-regulated in control implants in this study was TNF-α, a well-established mediator related to peri-implantitis–related bone loss [35]. Remarkably, both TNF-α and IL-17 are related to osteoclast formation and bone resorption, including around dental implants [36]. The biochemical outcomes of peri-implant crevicular fluid may characterize biological processes in peri-implant tissues and, according to our results, it could be assumed that external hexagonal implants placed at crestal bone level with a standard platform could harmfully modulate the local pattern of immunoinflammatory markers in crevicular fluid of implants, even in a clinically healthy peri-implant situation, encouraging marginal implant bone loss.

 

5. As a limitation of the study, the authors should further discuss the generalizability of their findings to other populations, as the ethnicities of the participants were not reported in the paper, and the participants had a mean age of 66 and did not demonstrate improvement in their diabetes during the course of the study.

The authors thank the reviewer observation. We added these suggestions to the discussion section: Given that a predisposition to develop peri-implant diseases and implant complications is observed in diabetic patients [37,38], the benefits of the use of the platform-switching concept in this patient profile could be extrapolated to, or at least be useful in, the long-term success of implants in T2DM patients. However, it is necessary to highlight that one limitation of the study could be the specificity of study population (Brazilian ethnicity) and other population could respond in a different pattern.

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

 

Comments and Suggestions for Authors

 

I have a few observations that can help improve the quality of the paper.

 

1-     In table 1, the Demographic characteristics of the control and test groups are exactly the same.  I think there is a mistake here. Please check again the demographic characteristics of the test and control groups and correct them in the paper.

2-     In the paper, F-statistic must be reported in the two-way RM ANOVA tables. You should give more details regarding the two-way RM ANOVA analysis. For example, F-statistic and p-value of the main effects of time (within-subjects effect), the main effects of group variable ( between- subjects effect), and the interaction between time and group variable (interaction effect) for each clinical parameter and immunoinflammatory marker level used in the study.

 

3-     In the study, p-values must be given for each comparison in the tables. The p-values must be presented in a single format in all tables and required sentences in the text. I recommend you the APA format to report p values.

 

4-     Apart from the normality assumption, the sphericity assumption also needs to be checked for the two-way repeated measures ANOVA test. Mauchly's Test of Sphericity should be used for this. If the assumption of sphericity is violated, a correction factor (such as Greenhouse-Geisser or Huynh-Feldt) should be used to adjust the degrees of freedom and p-values.

5-     In the last row of Table 5, You used not equal sign. It should be corrected with the appropriate sign.

6-     The information given in the Conclusion is not enough. Conclusion must be improved.

 

 

7-     The similarity rate is too high as 42% according to the Turnitin report. This rate must be reduced.

Author Response

Cover letter - Response to reviewers

 

Editorial Board

 

 24 November 2023.

Dear Editor,

 

We are submitting the revised manuscript entitled “Two-years follow-up of different approaches in type 2 diabetics rehabilitated with overdentures: A randomized clinical trial” for analysis. You can find below the responses to the reviewers' requests.

     The rationale for the current study was based in some investigations that have shown that the use of prosthetic abutments with reduced diameter in relation to the diameter of the platform seems to have significant potential for minimizing the reabsorption of peri-implant bone crest. Furthermore, the type of implant connection may influence peri-implant bone changes, as augmented peri-implant bone loss has been associated with external hexagonal connections, whereas the morse taper connection promotes a lower concentration and better distribution of stresses/strains in bone tissue around implants when compared with external hexagonal connections. Thus, considering the beneficial aspects of the morse taper implant combined with the platform-switching concept, it would be useful to determine whether this therapeutic approach could be considered a better alternative than hexagonal external implant with prosthetic intermediate of diameter equal to the platform  in the rehabilitation with dental implants of individuals with T2DM, since these patients may be more prone than non-diabetic patients to peri-implant changes, both from the point of view of marginal bone remodeling and local changes in mediators of the host immune response.

     This investigation showed, by the first time, that in individuals with T2DM rehabilitated with overdentures, the use of a conical implant installed below the level of the crestal bone and associated with a prosthetic intermediate of a diameter smaller than that of the implant platform resulted in reduced bone remodeling and better clinical conditions, and positively modulated peri-implant immunoinflammatory molecules.

     We, the undersigned authors, agree that the above-referenced manuscript is original, has not been published elsewhere, and is being submitted solely to the MDPI journals.

 

Thank you in advance,

Marcio Z. Casati (Correspondent author)

 

 

 

 

 

 

 

 

 

 

 

 

Reviewer 2

I have a few observations that can help improve the quality of the paper.

• In table 1, the Demographic characteristics of the control and test groups are exactly the same. I think there is a mistake here. Please check again the demographic characteristics of the test and control groups and correct them in the paper.

The authors thank the reviewer considerations. As the study followed the split-mouth design, each patient received two dental implants used to retain the rehabilitation were randomly assigned through a computer-generated list. This way, the values from baseline are the same for the evaluated parameters.

 

• In the paper, F-statistic must be reported in the two-way RM ANOVA tables. You should give more details regarding the two-way RM ANOVA analysis. For example, F-statistic and p-value of the main effects of time (within-subjects effect), the main effects of group variable (between- subjects effect), and the interaction between time and group variable (interaction effect) for each clinical parameter and immunoinflammatory marker level used in the study.

The authors thank the reviewer considerations. Data requested was added for data regarding FPG and HbA1c of the study population over time. For clinical parameters (MBoP, MPI, PGM, PPD and CAL) and tomographic assay, once the distribution was not normal, Wilcoxon test was used to distinguish inter-group differences and the Friedman test for intra-group analysis. After receiving the reviewer's suggestions and comments, we sent our data to a specialized analysis with a statistical specialist in order to adequately attend to the requests. All data was analyzed again and there were not important differences in results. However, the tests were adequate according to the normality analysis.

 

• In the study, p-values must be given for each comparison in the tables. The p-values must be presented in a single format in all tables and required sentences in the text. I recommend you the APA format to report p values.

 

The authors thank the reviewer considerations and p-values were added.

 

• Apart from the normality assumption, the sphericity assumption also needs to be checked for the two-way repeated measures ANOVA test. Mauchly's Test of Sphericity should be used for this. If the assumption of sphericity is violated, a correction factor (such as Greenhouse-Geisser or Huynh-Feldt) should be used to adjust the degrees of freedom and p-values.

Repeated measures ANOVA was used to check whether there was an effect of time on the variables fasting glucose and glycated hemoglobin, the null hypothesis was accepted and there was no effect of time. Furthermore, the test verified that there is no sphericity, so the Greenhouse-Geisser correction was used.

Fasting glucose [Z (2.21; 37.66) = 0.373] p=0.712; Glycated hemoglobin [Z (2.065, 35.106) = 0.253] p=0.785

5-     In the last row of Table 5, You used not equal sign. It should be corrected with the appropriate sign.

The authors thank the reviewer, and the correct sign was used.

 

6-     The information given in the Conclusion is not enough. Conclusion must be improved.

The authors improved the conclusion as requested.

 7-     The similarity rate is too high as 42% according to the Turnitin report. This rate must be reduced.

The authors reviewed the manuscript regarding similarity.

 

Round 2

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

Dear Authors,

You have made efforts to reduce the similarity rate; however, the similarity rate remains relatively high. It is crucial to further reduce this rate for the improvement of the manuscript.

Author Response

 

The authors reviewed the manuscript regarding similarity.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

change de word swift to switch

it is written that is a split mouth design study, but it is not explained like this, please check the methods

demographics should be divided in test and control

Reviewer 2 Report

Comments and Suggestions for Authors

In relation to the manuscript entitled "Two-year follow-up of different approaches in type 2 diabetics rehabilitated with overdentures: A randomized clinical trial" which I received for review.

The authors presented a randomized clinical trial comparing the crestal bone levels of patients restored with implant over dentures over two types of implant designs (external hexagon and morse tapered) with  two types of implant abutments  (butt joint or platform switched) inserted at two different levels (Crestal or subcrestal).  And used clinical parameters, immunoassays, and tomographic analysis to determine the outcomes of both approaches. 

The study is interesting because the methods described are commonly used in the dental  field and considering the increasing population diagnosed with T-II diabetes have clinical relevance. 

 

However, there are some aspects that require clarification before publication:

Comments:

-The authors repeatedly use the word "intermediate" but, the word "intermediate" does not appear in the glossary of prosthodontics terms. Therefore if the authors are  referring to the "abutment", then, please replace "intermediate" by "abutment" in all the text. This is for clarity and uniformity with current standards.

-In page 2, in the following sentence "In this context, studies have shown that the use of prosthetic abutments with platform swift concept..." Please replace the word "swift"  by  "shift"  or  "switch"

-How the authors accounted for the variability between patients  in the buccal bone thickness, soft tissue phenotype and their influence in the stability of the peri implant bone?

-Was the bone flattened previous to the implant bed preparation?

-Were the implants inserted in the center of the ridges?

-Please define clearly how the oral hygiene was standardized, what oral hygiene methods were instructed and taught to   the patients to reduce variability and the influence of  oral hygiene on the results?

-At what point the soft reline was completed? Can the reline affect the conditions of the peri-implant soft or hard tissues? 

-How the position of the implants within the interforaminal area was determined? The authors said that the denture was duplicated and used for the surgery but, what criteria was used for selecting the implant bed for example bone availability? 

-Was the implant stability recorded at the moment of insertion? 

-At the  time  of the second surgery, how the dimensions  of the abutments was determined? what torque was used for their connection to the implants?

-In page 3, las line of treatment protocol the authors stated "All parameters were assessed at baseline and then reassessed 12- and 24-months" when is baseline ? 

-In page 4, clinical examination subsection. Peri-implant margin gingival (PMG/mm): distance from the implant platform to the peri-implant..." what?The authors completed four measures per implant site, and then collated all and present these as mean values per implant? Please clarify

-In page 4. peri-implant fluid subsection. Please explain what was the base-line for the collection of peri-implant fluid. It was after the connection of the abutment? or the day of the restoration delivery?

-In page 4. tomographic evaluation. Here in the tomographic evaluation also it is not clear what is the base-line. Please clarify

-Also in tomographic evaluation. Please include images with landmarks reflecting the method of measurement of the crestal bone heigth. 

Please also include representative images of the buccal, mesial, lingual and distal bone levels of the measurements. It seems that the authors completed three CBCTs  which is unusual considering ALARA. Please clarify  why not using periapical radiographies for the evaluation of the crestal bone.  Also, having the possibility of a tridimensional evaluation, why not a volumetric evaluation of bone loss, instead of a linear evaluation?Please clarify

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