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  • Pilar Barahona1,
  • Braulio Santibáñez1 and
  • Andrés Celis2
  • et al.

Reviewer 1: Jong-Hwa Jang Reviewer 2: Anonymous Reviewer 3: Anonymous Reviewer 4: Anonymous

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript title, "Removable dental prostheses and handgrip strength in the elderly population of the Chilean public and private health system," is an interesting topic. However, to further validate its scientific merit, the following insightful revisions are needed from a methodological perspective.

  1. Introduction Section

"The Chilean private health system (Isapres) also includes EMPAM, which specifies the providers that beneficiaries must visit. If people choose to get the exam from providers other than those designated by their insurance, they forfeit the free benefit. They receive a thorough evaluation there, but must pay for the tests they request. Maintaining natural dentition or using removable dental prostheses (RDPs) is crucial for maintaining masticatory function, ensuring adequate nutrition, and preventing geriatric syndromes in the elderly population (EP)." Please provide literature that supports this theoretical basis.

  1. Methods Section

- Please add exclusion criteria for participant selection.

- I recommend that you organize the methodology section into subheadings, such as Participants, Interventions, Data Collection Process, and Statistical Analysis, to improve readability.

- Assessing the reliability of the data is important. Please provide detailed information about the investigators who participated in the data measurement in this study and the training process that ensured consistency of measurement.

- While the grip strength was measured after adjusting for sex, age, risk of malnutrition, and BMI, were control variables, such as the number of existing teeth or implant teeth, that could affect masticatory strength, measured?

- Please also provide a more detailed description of how chewing ability was categorized according to the Eichner index.

- Discuss with a statistician whether linear mixed regression analysis is appropriate for the pre- and post-test results. Generally, repeated measures ANOVA or ANOVA seems appropriate for this study.

  1. Results Section

- In Table 2, add the standard deviation along with the mean for grip strength values.

 

  1. Discussion Section

- I believe the insights into the research results can be enhanced by expanding the comparative discussion with related literature. Please add limitations of this study and future research directions.

  1. Other

- A review of the references is needed. Twenty references are cited in the text, but only 26 are presented.

Comments for author File: Comments.pdf

Author Response

 

To Reviewer Nº1.

 

Introduction section:

 

  • The Chilean private health system (Isapres) also includes EMPAM, which

specifies the providers that beneficiaries must visit. If people choose to get

the exam from providers other than those designated by their insurance,

they forfeit the free benefit. They receive a thorough evaluation there, but

must pay for the tests they request.

 

Reference number 18 was incorporated:

18- Superintendencia de Salud. Gobierno de Chile.  Available at:   https://www.superdesalud.gob.cl/568/w3-article-6487.html?noredirect

 

  • Maintaining natural dentition or using removable dental prostheses (RDPs) is crucial for maintaining masticatory function, ensuring adequate nutrition, and preventing geriatric syndromes in the elderly population.

 

Reference number 21 was incorporated:

 

21- Chan, A.K.Y.; Tsang, Y.C.; Jiang, C.M.; Leung, K.C.M.; Lo, E.C.M.; Chu, C.H. Diet, Nutrition, and Oral Health in Older Adults: A Review of the Literature. Dent. J.2023, 11, 222. https://doi.org/10.3390/dj11090222

 

Method section:

 

- Please add exclusion criteria for participant selection.

 

Exclusion criteria were included: “Exclusion criteria included refusal to participate, cognitive or sensory impairments, and functional dependence that prevented reliable evaluation”.

 

I recommend that you organize the methodology section into subheadings, such as Participants, Interventions, Data Collection Process, and Statistical Analysis, to improve readability.

 

Thank you for the suggestion; we have added subheadings to the Methods section.

 

- Please provide detailed information about the investigators who participated in the data

measurement in this study and the training process that ensured consistency of measurement.

 

Quality assurance: Three calibrated operators conducted all clinical and measurement procedures. Inter-operator agreement was substantial (Kappa = 0.79), confirming the reliability of classification and outcome measurement.

 

 

- While the grip strength was measured after adjusting for sex, age, risk of malnutrition, and BMI, were control variables, such as the number of existing teeth or implant teeth, that could affect masticatory strength, measured?

 

Thank you for this comment. Masticatory status was recorded using the Eichner Index, which—as applied in this study—counts occlusal contacts provided by natural teeth as well as fixed and implant-supported prostheses. Therefore, factors such as the number of posterior teeth and the presence of implant-supported units were included within the Eichner classification, which characterizes functional occlusal support. We clarified this point in the Methods section and added a brief note to the manuscript to make this explicit.

“Masticatory status was assessed with the Eichner Index, which classifies functional occlusal support based on the presence of support zones formed by natural teeth, fixed prostheses, or implant-supported prostheses. This variable was used to characterize participants’ masticatory capacity.”

 

- Please also provide a more detailed description of how chewing ability was categorized according to the Eichner index.

 

Masticatory function was assessed using the Eichner index, which categorizes occlusal support based on contacts in four posterior support zones (left and right premolar–molar regions). Occlusal contacts were identified at maximum intercuspation with articulating paper during light bite closure, and the classification was made by calibrated examiners. Category A indicates contacts in all four support zones (full posterior support). Category B indicates contacts in one to three support zones (reduced posterior support). Category C indicates no occlusal contacts in any of the support zones (no posterior support). For this analysis, categories B and C were combined to represent impaired posterior support. The Eichner Index categories, which include patients with premolar and molar loss, correspond to categories B and C.

 

- Discuss with a statistician whether linear mixed regression analysis is appropriate for the pre- and post-test results. Generally, repeated measures ANOVA or ANOVA seems appropriate for this study.

 

 

Thank you for this suggestion. We intentionally used linear mixed-effects regression (LMM) for the pre–post analysis because it (i) accounts for within-person correlation through random effects, (ii) includes all available cases under missing-at-random (MAR) conditions without listwise deletion, and (iii) flexibly adjusts for covariates (sex, age, BMI, risk of malnutrition) within a single framework. In contrast, repeated-measures ANOVA requires complete data (or ad-hoc imputation) and assumes stronger covariance structures; with any attrition or intermittent missingness, RM-ANOVA can produce biased estimates or lower power. These benefits of LMM in cases with multiple missing data points are well-documented (e.g., Krueger & Tian, Biol Res Nurs 2004;6(2):151–157. doi:10.1177/1099800404267682).

 

Notably, when data are complete and balanced, LMM and RM-ANOVA yield equivalent conclusions regarding the time effect; therefore, our choice neither inflates Type I error nor sacrifices accuracy, offering a more robust and efficient analysis for real-world pre–post data. If useful, we can also present a complete-case RM-ANOVA as a sensitivity analysis to show consistent results.

 

Results Section:

 

- In Table 2, add the standard deviation along with the mean for grip

strength values.

 

We incorporated the confidence intervals for the means, because that is the most appropriate metric regarding the mixed linear methods approach.

 

 

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

thank you for submitting your manuscript entitled “Removable Dental Prostheses and Handgrip Strength in the Elderly Population of the Chilean Public and Private Health System” The topic you address is high relevance, as handgrip strength is an important functional marker of frailty and sarcopenia, closely linked to nutrition/masticatory function. The language of the manuscript is generally clear and appropriate. Nevertheless, I have several points that should be addressed before the paper can be considered further:

Introduction

  • Please provide references to support the following statements:

Page 1, lines 34–35: “Although the Chilean population has a life expectancy of over 80 years, total life expectancy includes both healthy and unhealthy years.”

Page 1, line 36: “The portion aged 60 and over accounts for 18% (3.5 million).”

Page 2, line 46: “Handgrip strength (HGS) is a strong predictor of sarcopenia, a condition that contributes to frailty.”

Methodology

The prospective pre/post design is generally suitable to capture short-term effects of prostheses. However, the lack of a control group means that external influences on handgrip strength cannot be excluded:

  • The description of the cohort reveals marked differences: the public cohort was older on average (81 vs. 75 years) yet showed better handgrip strength values.
  • A potential weakness is the data source for the private cohort, which relies on secondary data and may be less standardized and thus less comparable.
  • Calf circumference and BMI are relatively crude indicators of muscle mass and nutritional status; more sensitive measures (e.g., bioelectrical impedance analysis, DXA) would have been preferable.
  • Handgrip strength was measured only once and on one side (dominant hand); repeated measures would have improved reliability.
  • The observation period of only 15 days is very short and does not capture long-term adaptation to prostheses.

These limitations should be discussed in the Discussion section to provide a more balanced interpretation of the results.

Author Response

To Reviewer Nº2.

 

Introduction

  • Please provide references to support the following statements:

Page 1, lines 34–35: “Although the Chilean population has a life expectancy of over 80 years, total life expectancy includes both healthy and unhealthy years.”

Reference Nº1 was incorporated

  • Moreno et al . Socioeconomic inequalities in life expectancy and disability-free life expectancy among Chilean older adults: evidence from a longitudinal study. BMC Geriatrics (2021) 21:176. https://doi.org/10.1186/s12877-021-02126-9
  •  

Page 1, line 36: “The portion aged 60 and over accounts for 18% (3.5 million).”

Reference Nº 2 was incorporated

  • Inzunza A , Madeira C. The Chilean pension withdrawals and the 2025 reform: Fiscal and retirement consequences. Journal of Pension Economics and Finance (2025), 1–27 doi:10.1017/S1474747225000058

 

Page 2, line 46: “Handgrip strength (HGS) is a strong predictor of sarcopenia, a condition that contributes to frailty.”

Reference Nº10 was incorporated

     10- Vaishya et al. Hand grip strength as a proposed new vital sign of health: a narrative review of evidences. Journal of Health, Population and Nutrition (2024) 43:7. https://doi.org/10.1186/s41043-024-00500-y

 

These limitations should be discussed in the Discussion section to provide a more balanced interpretation of the results.

New references from numbers 25 to 33 were incorporated in the discussion section to address these factors

 

Reviewer 3 Report

Comments and Suggestions for Authors

This was a very interesting manuscript that evaluates the correlation between partial denture use and hand grip strength. Decreased Hand grip strength is an indicator of risk of frailty and geriatric syndromes.

 

This is an interesting subject that I have not seen in the dental literature. The manuscript ties in prostheses with systemic health which is interesting and certainly needed in our evidence base.

 

Regarding the references, they do a great job of the medical aspect (calf diameter, etc), but the dental literature aspect could be improved. I would recommend including references that discuss tooth loss and comorbidities.  There is a recent review (Felton et al) and others. There is also a lot of literature about the oral health quality of life with the use of RPDs that would also strengthen the dental aspect of this manuscript.

 

The methods are different for the private and public cohort. Could you please address this in the discussion? Could this have any impact on the accuracy of the results? Additionally, is all of this data routinely gathered in Chilean private practices (HGS, calf diameter, etc)? Or were the practitioners in the private sector gathering this data for another reason? In other countries this is not a routine practice and would be worth addressing how and why this data was gathered.

 

Lastly, an abbreviation MPF was used in the methods, but the full unabbreviated word was not defined.  Please clarify the abbreviation.  Thanks!

Author Response

To Reviewer Nº3.

-Regarding the references, they do a great job of the medical aspect (calf diameter, etc), but the dental literature aspect could be improved. I would recommend including references that discuss tooth loss and comorbidities.  There is a recent review (Felton et al) and others. There is also a lot of literature about the oral health quality of life with the use of RPDs that would also strengthen the dental aspect of this manuscript.

 

New references from numbers 26 to 31 address this comment in the Discussion section

 

-The methods are different for the private and public cohort. Could you please address this in the discussion? Could this have any impact on the accuracy of the results? Additionally, is all of this data routinely gathered in Chilean private practices (HGS, calf diameter, etc)? Or were the practitioners in the private sector gathering this data for another reason? In other countries this is not a routine practice and would be worth addressing how and why this data was gathered

 

Thank you very much for this comment. To clarify, the EMPAM is a routine examination to assess the health status of the elderly. It involves anthropometric measurements, as well as assessments of functional, mental, and social aspects. The EMPAM is used in both public and private health systems and includes HGS, calf diameter, and BMI. 

 

 

- Lastly, an abbreviation MPF was used in the methods, but the full unabbreviated word was not defined.  Please clarify the abbreviation.

 

  Solved

 

 

 

Reviewer 4 Report

Comments and Suggestions for Authors

Suggestions for Authors
Include a control group without prosthetic intervention - or find articles /refferences. At least adress the problem

Extended follow-up beyond 15 days would show benefits and clinical relevance of observed changes

Address potential selection bias, as private patients may represent a different risk profile than those in the public system

Consider analyzing within-group changes as the primary outcome rather than between-group comparisons

Author Response

To Reviewer Nº4.

 

-Include a control group without prosthetic intervention - or find articles /references. At least address the problem

 

 

The improved discussion section addresses the population without prosthetic interventions and its consequences.

 

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript has been improved through revision. Thank you.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

thank you very much for implementing my suggestions for improvement in the manuscript: Removable dental prostheses and handgrip strength in the elderly population of the Chilean public and private health system