UNIVERSIDADE ESTADUAL PAULISTA

“JÚLIO DE MESQUITA FILHO”

Instituto de Ciência e Tecnologia

Campus de São José dos Campos

ORIGINAL ARTICLE DOI: https://doi.org/10.4322/bds.2024.e4163

Braz Dent Sci 2024 Apr/June;27 (2): e4163

This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in

any medium, provided the original work is properly cited.

Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Existe diferença nos níveis de estresse oxidativo entre indivíduos com diabetes tipo 2 com e sem periodontite?

Revisão Sistemática

Walder Jansen de Mello LOBÃO1 , Cláudia Callegaro de MENEZES1 , Guido Artemio MARAÑÓN-VÁSQUEZ2 ,

Daniele MASTERSON3 , Lucianne Cople MAIA2 , Maria Cynésia Medeiros de BARROS1 ,

Carina Maciel SILVA-BOGHOSSIAN1 , Carmelo SANSONE1 

1 - Departamento de Clínica Odontológica, Divisão de Periodontia, Faculdade de Odontologia, Universidade Federal do Rio de Janeiro,

Rio de Janeiro, RJ, Brazil.

2 - Departamento de Odontopediatria e Ortodontia, Faculdade de Odontologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro,

RJ, Brazil.

3 - Biblioteca Central do Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.

How to cite: Lobão WJM, Menezes CC, Marañón-Vásquez GA, Masterson D, Maia LC, Barros MCM, et al. Is there a difference in

the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review. Braz Dent Sci.

2024;27(2):e4163. https://doi.org/10.4322/bds.2024.e4163

ABSTRACT

Objective: The authors’ aim in this systematic review was to verify the scientic evidence for difference of

oxidative stress biomarkers in individuals with type 2 diabetes mellitus with and without periodontitis. Material

and Methods: Observational studies, baseline data of prospective and interventional studies were searched on

the following databases: Virtual Health Library, Web of Science, PubMed, Embase, Scopus, Cochrane Library,

Opengrey and Google Scholar. The electronic search was performed in June 01, 2020 until May 17, 2024 with

alerts until June 01, 2024. The quality assessment and the certainty of the evidence of the included studies were

evaluated through Fowkes and Fulton’s checklist and GRADEpro Guideline Development Tool. Results: Of 988

relevant articles, the authors included 9 studies for the nal analysis. Among those studies, 4 cross-sectional, 3

case-control, and 2 interventional studies were included. The analysis of non-randomized clinical trials properly

reported most of the criteria analyzed in Summary questions (Bias, Confounding and Chance) as present in 3

studies. In six studies confounding factors were no detected. Due to the variation in the study results and clinical/

methodological heterogeneity, a meta-analysis was not appropriate. The studies reported high concentrations of

oxidizing agents and low antioxidants levels in individuals with type 2 diabetes mellitus and periodontitis when

compared to with no periodontitis. Conclusion: Considering the few studies found, the methodological aws,

few markers studied and absence homogeneity in the evaluation of redox balance markers, as well as, the very

low certainty of the evidence among included studies, it was not possible to determine whether there are or not

differences in the oxidative stress levels in individuals with type 2 diabetes with and without periodontitis, and

therefore, further prospective observational and interventional studies are recommended.

KEYWORDS

Diabetes mellitus non-insulin dependent; Periodontitis; Periodontal diseases; Oxidative stress; Antioxidants;

Free radicals.

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is a

significant risk factor for periodontitis and

glycemic imbalance is the determining factor

for bone loss that increases the risk and

severity of periodontal disease [1]. The altered

immunological response in T2DM influences

periodontal diseases by altering the inammatory

responses, and periodontal wound healing.

Additionally, it promotes the accumulation of

advanced glycation end products (AGEs) that

induce high levels of pro-inammatory cytokines,

and causes oxidative stress (OS) [2].

Oxidative stress occurs when, due to a higher

concentration of reactive oxygen species (ROS)

or a decrease in antioxidant capacity, there is a

lack of homeostasis [3]. This can occur in several

systemic conditions. According to the literature,

the tissue destruction that occurs in periodontal

diseases can be caused by the high production of

ROS by inammatory cells, leading to oxidative

stress [4,5].

The increase in ROS of local and systemic

forms found in these pathologies can signicantly

affect the functioning pattern of several tissues

and is closely related to the comorbidities

associated with T2DM [4-6]. The increase in

oxidative damage [7,8] and lower levels of

antioxidants [9,10] were found in patients with

periodontitis compared to periodontally healthy

individuals. The periodontal inflammatory

condition can be explained by the local

and systemic concentrations of some OS

biomarkers [8].

Periodontitis and T2DM are diseases with

characteristics of chronic inammation and a

permanent increase in OS [1,8]. However, no

systematic review has assessed the level of OS

biomarkers in type 2 diabetic individuals with and

without periodontitis. Therefore, the aim of this

systematic review was to answer the following

question: Is there a difference in the level of

OS in individuals with T2DM with and without

periodontitis?

METHODS

Registration and protocol

This review was registered in the PROSPERO

database under the protocol (https://www.crd.

york.ac.uk/PROSPERO) ID: CRD42020190010,

on August 7th, 2020 and was reported in accordance

with the PRISMA checklist of systematic reviews

and meta-analyses [11].

RESUMO

Objetivo: O objetivo dos autores nesta revisão sistemática foi vericar a evidência cientíca para a diferença

de biomarcadores de estresse oxidativo em indivíduos com diabetes mellitus tipo 2 com e sem periodontite.

Material e Métodos: estudos observacionais, dados de base de estudos prospectivos e intervencionistas foram

pesquisados nas seguintes bases de dados: Biblioteca Virtual em Saúde, Web of Science, PubMed, Embase, Scopus,

Cochrane Library, Opengrey e Google Scholar. A busca eletrônica foi realizada no período de 01 de junho de

2020 até 17 de maio de 2024, com alertas até 01 de junho de 2024. A avaliação da qualidade e a certeza da

evidência dos estudos incluídos foi realizada através da lista de checagem Fowkes and Fulton’s e da Ferramenta

de desenvolvimento de diretrizes GRADEpro. Resultados: Dos 988 artigos relevantes, os autores incluíram 9

estudos para a análise nal. Entre esses estudos, foram incluídos 4 estudos transversais, 3 de caso-controle e 2

de intervenção. A análise dos ensaios clínicos não randomizados relatou adequadamente a maioria dos critérios

analisados nas questões resumo (Viés, Confundimento e Resultados ao caso) presentes em 3 estudos. Fatores de

confusão não foram detectados em seis estudos. Devido à variação nos resultados do estudo e à heterogeneidade

clínica/metodológica, não foi possível realizar uma meta-análise. Os estudos relataram altas concentrações de

agentes oxidantes e baixos níveis de antioxidantes em indivíduos com diabetes mellitus tipo 2 e periodontite

quando comparados a indivíduos sem periodontite. Conclusão: Considerando os poucos estudos encontrados, as

falhas metodológicas, poucos marcadores estudados e ausência de homogeneidade na avaliação dos marcadores

do balanço redox, bem como a baixíssima certeza da evidência entre os estudos incluídos, não foi possível

determinar se há diferenças nos níveis de estresse oxidativo em indivíduos com diabetes tipo 2 associado e não

à periodontite e, portanto, outras observações prospectivas e estudos de intervenção são recomendados.

PALAVRAS-CHAVE

Diabetes mellitus não insulino-dependente; Periodontite; Doenças periodontais; Estresse oxidativo; Antioxidantes;

Radicais livres.

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Eligibility criteria

The eligibility criteria were dened based on

the PECO research strategy as follows:

1. Participants (P): T2DM individuals of

both genders and without distinction

in age and ethnicity. Studies including

individuals with the following conditions

were excluded: chronic kidney disease,

malignant neoplasms, AIDS (Acquired

Immunodeficiency Syndrome), pregnant

or lactating women, immunosuppression

by medication, autoimmune diseases,

evidence of other systemic diseases ASA

III and IV, smokers or former-smokers for

less than twenty years, users of orthodontic

appliances, history of use of steroidal or

non-steroidal anti-inammatory drugs in

the last three months prior to the study

and during research, use of antibiotics in

the last six months prior to the study and

during research, as well as individuals who

underwent supra and subgingival scaling

and/or periodontal surgery in the last 6

months before the investigation.

2. Exposure (E): Presence of Periodontitis.

Selection criteria established: Probing

depth (PD) ≥ 4mm, Clinical attachment

level (CAL) ≥ 4mm, presence of biofilm

and bleeding on probing (BOP) > 10%.

The examination should be performed by

calibrated examiners, performing a full-

mouth periodontal examination (six sites per

tooth), using the North Carolina periodontal

probe.

3. Comparison (C): Absence of Periodontitis.

Selection criteria established: PD ≤ 3mm, CAL ≤

3mm, little or no biolm, and BOP <10%.

The examination should be performed by one

or more calibrated examiners, performing

a full-mouth periodontal examination (six

sites per tooth), using the North Carolina

periodontal probe.

4. Outcome (O): OS levels for different

parameters, such as AGEs, calcium, catalase

(CAT), glutathione reductase (GRd), iron,

magnesium, malondialdehyde (MDA),

nitric oxide (NO), oxidative stress index

(OSI), protein carbonyl (Protein CO),

small molecular antioxidant capacity

(SMAC), superoxide dismutase (SOD),

total antioxidant capacity (TAC), total

oxidant status (TOS), vitamin C, zinc. If the

outcomes of interest were not measured or

not reported the studies were considered

ineligible.

Information sources

A systematic search of the literature was

conducted on the following electronic databases:

MEDLINE using the PubMed, Scopus, Embase,

Web of Science, Cochrane Library and Virtual

Health Library (VHL). Other sources were

consulted through OpenGrey and Google Scholar.

The electronic search was initially performed in

June 2020, and database alerts with the search

strategy were created in each database and were

set to retrieve newly published articles until May

17, 2024.

Literature search strategy

The search strategy included Medical Subject

Headings (MeSH) terms, entry terms, free terms

and keywords related to the aim of this review.

No restrictions were placed on publication date

or language. The strategy was developed using

the boolean operators AND/OR, Medical Subject

Headings (MeSH) terms, keywords, and other

free terms related to “Diabetes mellitus, non-

insulin dependent”; “Periodontitis, Periodontal

diseases”; and “Oxidative stress, Antioxidants,

Free radicals, Oxidants”. The strategy was rst

idealized for Pubmed search engine use and

then, adapted to each database according to

their syntaxes rules. Specic search strategies

were developed for each database (Appendix

1) with no restrictions on language or date.

In addition, lters regarding VHL (virtual health

library) database to LILACS and BBO collections

were applied. A manual search was carried out

among the selected articles. Experts in the eld

were identied in the Scopus database by the

“Analyze results tool” and contacted for ongoing

studies or unpublished results regarding the

focused question, using e-mail contact for up to

ve attempts. The search strategy was organized

and carried out by an expert librarian (D.M.).

Articles from Google Scholar covered the

first 100 matches and were then manually

processed to check if possible eligible papers were

missed from the main database search engines.

When necessary, articles published in languages

other than English, Spanish, and Portuguese

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

were translated using the Google® Translate

Tool [12].

Selection process

Observational studies and baseline data

of prospective/interventional studies, with the

variables of interest, were included. Reviews, case

reports, case series, expert opinions, and animal

studies were excluded.

The retrieved articles were exported to

Endnote® Web [13] to list, organize and remove

duplicates. Authors and co-authors of studies that

were not retrieved in the full text were contacted

by e-mail up to ve attempts, from June 2020 to

May 17, 2024.

All titles, abstracts, and full-text reading of

the articles were independently analyzed by two

reviewers (W.J.M.L. and C.C.M.) to determine

whether they met the eligibility criteria. Whenever

differences occurred between them, a consensus

should be reached. When a study of interest had

no abstract available, the study had its full text

assessed for eligibility decision. At this stage,

articles that did not meet the eligibility criteria

were excluded. Next, selected articles were read

in full. If a study had a sample overlapping with

other studies and the same methodology criteria

assessed, the least complete study was excluded.

Whenever the two reviewers were unsure about

the inclusion/exclusion of any publication, a

discussion with a third reviewer (L.C.M.) was

taken to solve any disagreement. After full-text

examination were registered the reasons for

exclusion of articles.

Data collection process/ data items

Data extraction regarding authors, year

and country of the study, characteristics of

participants (sample size, sample age, and T2DM

duration in years), exposure (diagnostic criteria

for periodontitis), body uid collected (serum,

saliva, and gingival crevicular uid), assessment

methods to oxidative stress parameters and

statistics outcomes of interest (inferential and

descriptive data) were extracted independently

by 2 researchers (W.J.M.L. and C.C.M.).

Any differences between the two examiners were

solved by a third investigator (L.C.M.).

When missing data were detected, the

corresponding author was contacted through

electronic mail for up ve consecutive weeks.

In case there were no return from the authors to

identify data in graphs, It was used the digital

program WebPlotDigitizer online [14] to identify

data in graphs from authors who did not respond

to emails. Another author conrmed the accuracy

of extracted data.

Quality assessment

The internal validity of the included studies

was evaluated according to adaptations of Fowkes

and Fulton’s [15] critical appraisal of published

research guidelines (Appendix 2).

Effect measure

Due to the variability of the sample size

between the studies, an adaptation was performed

to determine the central value and variance of

the samples. For outcomes, mean and standard

deviation were used.

Synthesis methods and certainty of evidence

assessment

Narrative syntheses were conducted for the

results reported on each oxidative stress parameter.

The certainty of evidence was determined using

the Grading of Recommendations, Assessment,

Development, and Evaluation Pro software

(GRADEpro Guideline Development Tool) for the

synthesized results on each OS parameter [16].

The risk of bias, inconsistency, indirectness,

suspicion of publication bias, presence of a large

effect, dose-response gradient, and plausible

confounders were the items considered to rate

the overall certainty of evidence [17,18]. All the

judgments were adapted to qualify the evidence

synthesized in a narrative way [19].

RESULTS

Study selection

A total of 988 studies were identied and

retrieved: 956 from the database search, 8 from

the alerts, and 24 from other sources. The main

databases used as sources for studies were VHL

(n=282) and PubMed (n=239), followed by Web

of Science (n=192), Embase (n=83), Scopus

(n=72), Cochrane Library (n=50), opengrey

(n=0), and additional records identied through

Google Scholar (n=24). The 295 duplicated

titles/abstracts were eliminated through EndNote

Software, and 76 through manual exclusion.

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

All titles and abstracts (n=617) were analyzed

and 585 were excluded according to the study

criteria, resulting in 32 remaining studies,

which were assessed for eligibility. Twenty-three

were excluded due to the following reasons:

absence of group T2DM without Periodontitis

(n=21), research participants with more than

one systemic disease (n=1), and an article that

contained a part of an included study in this

systematic review (n=1) (Appendix 3).

Regarding the records identied by other

resources, the rst one hundred matches from the

35700 results in Google Scholar were selected for

the study, and none were recorded in Opengrey.

There were found 36 duplicate records, which

were manually removed, and another 64 records

were excluded after title/abstract reading. Alerts

were set by June 01, 2024 in Databases, and

eight articles were retrieved. However, they did

not meet the inclusion criteria for eligibility.

Study selection process is shown in the owchart

(Figure 1). Nine articles were screened for the

nal analysis.

Study characteristics

The included studies were conducted

in institutions such as universities, clinical

centers, or hospitals in three different

countries (Table I). Among those studies,

4 cross-sectional [21,25,27,28], 3 case-control [23,24,26]

and 2 interventional [20,22] studies were

included. In all studies, low levels of antioxidants

were evaluated as primary outcome. Studies

varied greatly regarding age, ranging from

20 years [23] to 71 years [20].

Periodontal parameters, plaque index

(PI), BOP, PD, and CAL, were reported for

periodontitis diagnosis, represented as mean

and standard deviation [20-25,27] or by mean

percentage [26,28]. The patients in the included

studies had chronic periodontitis, according to

Figure 1. Flowchart diagram of literature search according to Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA)

guidelines, published in 2020.

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Table I - Characteristics of the sample and data collection of the 9 included studies.

Authoretal. /

year / Country Study design

Characteristics of Subjects Exposure Outcomes Numeric Data

Sample size Sample age

(Mean±SD)

Diabetes duration in

years (Mean±SD)

Diagnostic criteria

for periodontitis Body ﬂuid Oxidative Stress Parameters

(Assessment method)

Oxidative stress markers (Mean±SD)

T2DM T2DM + P

Allenetal. (2011) [20]/

Ireland

Cross-sectional

T2DM: 20 T2DM: 55±7 T2DM: 5.7±16.9

- More than 16 teeth

with periodontal

pockets > 4mm in at

least 6 sites.

Serum

Small molecule

antioxidant capacity

(Chemiluminescence)

Probing depth (mm) 523.4±111.1 452.6±100.1

T2DM + P: 20 T2DM + P: 56±7 T2DM+P: 7.0±14.5 Plaque index (%)

They should be

on dose of oral

hypoglycemic drugs,

Anti-inﬂammatories,

statins, ace

inhibitors, β-blockers

and diuretics.

Bleeding on probing

(%) Protein carbonyl (ELISA) 1.99±0.85 2.71±0.94

Lathaetal. (2018) [21]/

India Intervention

T2DM: 10 T2DM: 56.8±8.71

The subjects

should have been

diagnosed with type

2 diabetes for at

least 5 years. They

should be on stable

dose of insulin/oral

hypoglycemic drugs.

- More than 20

teeth with clinical

attachment loss of ≥

5mm in at least 30%

of the sites.

Saliva

Malondialdehyde

(spectrophotometric

method)

2.19±1.62 2.17±0.52

Probing depth

(Mean±SD)

T2DM + P: 15 T2DM + P:

51.13±6.75

Plaque index

(Mean±SD)

Bleeding on probing

(Mean±SD)

Clinical attachment

loss (Mean±SD)

Nitric Oxide

(spectrophotometric

method)

1.76±1.02 9.08±2.33

Note: All patients in the diabetes group were diagnosed based on the criteria of the World Health Organization (Fasting glucose ≥126 mg/dL, HbA1c levels >5,6% and oral glucose tolerance test ≥200 mg/dL).

DNPH: 2, 4- dinitrophenylhydrazine method; T2DM: Type 2 diabetes mellitus individuals; T2DM + P: Type 2 diabetes mellitus with periodontitis individuals; ELISA: Enzyme-Linked Immunosorbent Assay; HbA1c:

Glycated hemoglobin; Nitro-PAPS: pyridylazo-N-propyl-N-sulfopropylaminoPhenol method; NR: Not reported; OCPC method: o-Cresolphthalein Complexone method; P: Periodontitis; qPCR: Quantitative Real-

Time polymerase chain reaction; † data obtained by WebPlotDigitizer online software.

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Authoretal. /

year / Country Study design

Characteristics of Subjects Exposure Outcomes Numeric Data

Sample size Sample age

(Mean±SD)

Diabetes duration in

years (Mean±SD)

Diagnostic criteria

for periodontitis Body ﬂuid Oxidative Stress Parameters

(Assessment method)

Oxidative stress markers (Mean±SD)

T2DM T2DM + P

Pendyalaetal. (2013) [22]/

India

Case-control

T2DM: 30

40-65 years

Time of diagnosis

for T2DM was not

informed.

- More than 14 teeth

with two or more

tooth sites with PD

≥ 4 mm or CAL of

4 mm that bled on

probing.

Saliva

Total antioxidant capacity

(spectrophotometric

method)

1.24±0.18 0.40±0.09

These patients

were not under any

oral hypoglycemic

agents and/or

insulin therapy

Probing depth (mm)

T2DM+ P: 30 Clinical attachment

loss (mm)

Probing depth ≥

4mm (%)

Clinical attachment

loss ≥4mm (%)

Plaque index (%)

Bleeding on probing

(%)

Pushpa Rani et al. (2013)

[27]

Cross-sectional

T2DM: 150 T2DM: 46.26 ± 10.02 Diagnosed by a

physician by means

of oral glucose

tolerance test, for

at least the past 5

years

- More than 30% of

the sites with CAL

≥ 3 mm and PD ≥ 5

mm, at least 2 teeth

in each quadrant

with the condition

of 20 teeth in all the

subjects. Serum

Vitamin C (DNPH method) 1.25±3.58 † 0.99±1.66 †

Probing depth (mm)

T2DM + P: 150 T2DM + P: 44.42 ±

10.37

Clinical attachment

loss (mm)

Zinc (Nitro-PAPS)

157.2±45.8 106.8±31.83

Glycated hemoglobin; Nitro-PAPS: pyridylazo-N-propyl-N-sulfopropylaminoPhenol method; NR: Not reported; OCPC method: o-Cresolphthalein Complexone method; P: Periodontitis; qPCR: Quantitative Real-

Time polymerase chain reaction; † data obtained by WebPlotDigitizer online software.

Table I - Continued...

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Authoretal. /

year / Country Study design

Characteristics of Subjects Exposure Outcomes Numeric Data

Sample size Sample age

(Mean±SD)

Diabetes duration in

years (Mean±SD)

Diagnostic criteria

for periodontitis Body ﬂuid Oxidative Stress Parameters

(Assessment method)

Oxidative stress markers (Mean±SD)

T2DM T2DM + P

Pushpa Rani (2015) [28] Cross-sectional

T2DM: 150 T2DM: 46.26±10.02

Diagnosed by a

physician by means

of oral glucose

tolerance test, for

at least the past 5

years

- More than 30%

of the sites with

clinical attachment

level (CAL) ≥ 3mm

and probing depth

(PD) ≥ 5 mm, at

least 2 teeth in

each quadrant with

the condition of

20 teeth in all the

subjects.

Serum

Calcium (OCPC) 8.59±0.86 11.79±2.07

T2DM + P: 150 T2DM + P:

44.42±10.37 Probing depth (mm) Iron (Ramsay’s dipyridyl

method) 76.53±20.23 114.9±40.91

Clinical attachment

loss (mm)

Magnesium (Absorbance of

520 nm, with Xylidyl Blue

dye reagent kit)

1.56±0.42 1.45±0.41

Zinc (Nitro-PAPS)

157.2±45.8 106.8±31.83

Shettyetal. (2016) [23]

/ Índia Intervention

T2DM: 30

25-60 years

Time of diagnosis

for T2DM was not

informed.

- More than 20

teeth present. Used

the classiﬁcation

of Löe (1967) to

periodontal disease:

gingival index,

plaque index and

retention index. Serum Magnesium (semi-

autoanalyzer) 1.01±0.28 0.92±0.23

T2DM+ P: 30 Gingival index (0, 1,

2 and 3)

Probing depth (0, 1,

2 and 3)

Retentetion index

system (0, 1, 2

and 3)

Glycated hemoglobin; Nitro-PAPS: pyridylazo-N-propyl-N-sulfopropylaminoPhenol method; NR: Not reported; OCPC method: o-Cresolphthalein Complexone method; P: Periodontitis; qPCR: Quantitative Real-

Time polymerase chain reaction; † data obtained by WebPlotDigitizer online software.

Table I - Continued...

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Authoretal. /

year / Country Study design

Characteristics of Subjects Exposure Outcomes Numeric Data

Sample size Sample age

(Mean±SD)

Diabetes duration in

years (Mean±SD)

Diagnostic criteria

for periodontitis Body ﬂuid Oxidative Stress Parameters

(Assessment method)

Oxidative stress markers (Mean±SD)

T2DM T2DM + P

Takedaetal. (2006) [24]/

Japan Cross-sectional

T2DM: 28

57.8± 12.1

T2DM: 8.0±7.7

- Subjects had ≥ 10

functional teeth and

more than one tooth

with CAL > 5 mm.

Serum Advanced Glycation End-

products (uninformed) 2.6±1.0 2.5±0.8

T2DM+ P: 69

T2DM+P: 8.6±7.6

Bleeding on

probing (Presence

or Ausence of

bleeding within 5

to 20 seconds after

probing)

Probing depth (mm)

The control with

medicaments was

not informed.

Clinical attachment

loss (%)

Glycated hemoglobin; Nitro-PAPS: pyridylazo-N-propyl-N-sulfopropylaminoPhenol method; NR: Not reported; OCPC method: o-Cresolphthalein Complexone method; P: Periodontitis; qPCR: Quantitative Real-

Time polymerase chain reaction; † data obtained by WebPlotDigitizer online software.

Table I - Continued...

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Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Authoretal. /

year / Country Study design

Characteristics of Subjects Exposure Outcomes Numeric Data

Sample size Sample age

(Mean±SD)

Diabetes duration in

years (Mean±SD)

Diagnostic criteria

for periodontitis Body ﬂuid Oxidative Stress Parameters

(Assessment method)

Oxidative stress markers (Mean±SD)

T2DM T2DM + P

Trivedietal. (2014) [25]/

Índia

Case-control

T2DM: 30

20-65 years,

categorizaded

(≤40 years and >40

years)

T2DM: 4.33±3.44

- Patients with two or

more tooth sites with

probing depth ≥ 4mm

or clinical attachment

loss (CAL) ≥ 4mm

that bled on probing.

Saliva

Malondialdehyde

(spectrophotometric

method) 1.91±1..72 10.79±8.07

T2DM+ P: 30 - Minimum number

of teeth not

informed.

T2DM+P: 5.53±4.05 Plaque index

(Presence or

Ausence)

Superoxide dismutase (Mc

Cord and Fridovich)

Gingival index

(Presence or

Ausence) 13.45±2.80 14.08±4.28

Were controlled

diabetics being

treated with

stable doses of

oral hypoglycemic

agents and /

or insulin by an

endocrinologista.

Probing depth (mm) Catalase (Mc Cord and

Fridovich)

Clinical attachment

loss (mm)

Glutathione reductase (Mc

Cord and Fridovich) 0.04±0.04 0.04±0.03

13.73±2.79 18.33±7.47

Serum

Malondialdehyde

(spectrophotometric

method) 13.01±5.55 15.91±6.98

Superoxide dismutase (Mc

Cord and Fridovich)

19.05±5.88 26.84±12.1

Catalase (Mc Cord and

Fridovich)

Glutathione reductase (Mc

Cord and Fridovich) 0.06±0.03 0.06±0.03

6.28±4.96 12.15±6.11

Glycated hemoglobin; Nitro-PAPS: pyridylazo-N-propyl-N-sulfopropylaminoPhenol method; NR: Not reported; OCPC method: o-Cresolphthalein Complexone method; P: Periodontitis; qPCR: Quantitative Real-

Time polymerase chain reaction; † data obtained by WebPlotDigitizer online software.

Table I - Continued...

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Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Authoretal. /

year / Country Study design

Characteristics of Subjects Exposure Outcomes Numeric Data

Sample size Sample age

(Mean±SD)

Diabetes duration in

years (Mean±SD)

Diagnostic criteria

for periodontitis Body ﬂuid Oxidative Stress Parameters

(Assessment method)

Oxidative stress markers (Mean±SD)

T2DM T2DM + P

Vincentetal. (2018) [26]/

India

Case-control

T2DM: 20

25-65 years

Participants

diagnosed with

type II DM by

a diabetologist

and under

treatment with oral

hypoglycemic drugs

and diet control

for a minimum of

6 months were

included

- Minimum of 20

teeth present with

at least 5 teeth

in each quadrant,

with a probing

depth (PD) of

≥5mm with clinical

attachment loss of

≥1mm in more than

30% of sites with

mild to moderate

periodontitis, and

presence of >30% of

sites with bleeding

on probing.

Gingival Fluid

Total antioxidant capacity

(Erel O’s novel automated

method)

0.77±0.27 0.69±0.19

T2DM + P: 20 Total oxidant status (Erel O’s

novel automated method)

Plaque index

Bleeding on probing

Oxidative stress index

(Erel O’s novel automated

method)

7.84±1.50 10.05±3.26

Probing depth (mm)

Clinical attachment

loss (mm) 1.00±0.52 1.39±0.62

Glycated hemoglobin; Nitro-PAPS: pyridylazo-N-propyl-N-sulfopropylaminoPhenol method; NR: Not reported; OCPC method: o-Cresolphthalein Complexone method; P: Periodontitis; qPCR: Quantitative Real-

Time polymerase chain reaction; † data obtained by WebPlotDigitizer online software.

Table I - Continued...

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Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

1999 AAP Classification [29]. The minimum

number of teeth of the research participants

in the included studies ranged from 10 [27] to

20 functional teeth [20,22,24].

Data on T2DM duration was introduced

in years and expressed in mean and

standard deviation. Most studies included

participants diagnosed with T2DM for at least

5 years [20,21,23,25,28]. A study included

participants with a minimum of 8 years of

diagnosis for T2DM [27], other with participants

at least 6 months of diagnosis [24], while two

studies [22,26] did not report on this data.

The OS biomarkers were analyzed

in more than one body fluid, including

serum [21-23,25,27], saliva [20,23,26] and

gingival uid (GF) [24], and were expressed in

mean and standard deviation, through different

methods, comparing gold-standard or not.

None of those studies directly cross-compared

biomarkers ndings between those body uids.

Among the OS biomarkers studied a large

number of antioxidants were evaluated such

as SMAC [28], TAC [24,26], vitamin C [25],

zinc [21,25], calcium [21], magnesium [21,22],

CAT, SOD and GRd [23]. In addition, two oxidant

agents were evaluated: NO [20] and iron [21].

Furthermore, biomarkers of cell damage due to

OS were also evaluated, such as Protein CO [28],

AGEs [27], MDA [20,23], TOS and OSI [24].

Only one study [23] evaluated the same

biomarkers (MDA, SOD, CAT, and GRd) in blood

and saliva, although no comparisons between

findings from both fluids were compared, as

mentioned before.

Quality assessment

For the quality assessment, the included

studies were classied according to the risk of bias,

confounding factors, and chance. Susceptibility to

bias and results occurred by chance were observed

in all analyzed studies [20-28]. Confounding

factors were observed in 3 out of the 9 analyzed

studies (Table II) [21,25,28]. According with the

criteria used, there was no sound study.

Results of individual studies and synthesis

Some of the included studies demonstrated

a significant correlation between high levels

of oxidizing compounds and individuals with

T2DM and periodontitis [20,21,27,28]. On the

other hand, other studies presented a decrease

in the levels of antioxidants in T2DM with

periodontitis, when compared to T2DM without

periodontitis [21-28]. Overall, the studies have

shown that individuals with T2DM presented high

OS levels, which are greater when associated with

periodontitis.

Oxidants

In individuals with T2DM and periodontitis,

Protein CO levels were higher compared with those

without periodontitis. The same result of high levels

was expressed for free radical damage markers

(MDA, TOS, and OSI) in T2DM with periodontitis

individuals when compared to T2DM individuals

without periodontitis [20,23,24]. In T2DM with

periodontitis individuals, the NO levels were

higher than in T2DM without periodontitis [20].

Pushpa Rani [27] shown that elevated calcium

and iron levels may be a contributing factor in

many inammatory conditions in T2DM with

periodontitis individuals.

Antioxidants

The included literature demonstrated that

Some antioxidants (SMAC, TAC, Vitamin C, Zinc,

Magnesium, CAT, SOD, and GRd) were detected

in low concentrations in individuals with T2DM

with no periodontitis. Additionally, those levels

were even lower in individuals with T2DM with

periodontitis [21-26,28].

Due to the variation in the study results and

clinical/methodological heterogeneity, a meta-

analysis was not appropriate.

Certainty of evidence

The certainty of the evidence was rated as

very low for all the syntheses. The risk of bias

affected the evidence because the included studies

had important methodological limitations that

could have altered the results. The evidence on

the outcomes of MDA and TAC was inconsistent

since there was variation in the reported effects

by the studies. The item imprecision was also

affected due to the reduced number of individuals

included in the syntheses (less than the threshold

of 400 recommended by GRADE) (Table III).

The certainty of the evidence for the outcomes

that included a single study (SMAC, Protein

carbonyl, NO, Vitamin C, Zinc, Ca, Iron, AGEs,

SOD, CAT, GRd, TOS, OSI) was lowered due

to the risk of bias and impression (insufcient

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Table II - Quality assessment according to Fowkes and Fulton

Guideline Checklist Allenetal.

(2011) [20]

Lathaetal.

(2018) [21]

Pen-

dyalaetal.

(2013) [22]

Pushpa

Rani et al.

(2013) [27]

Pushpa Rani

(2015) [28]

Shettyetal.

(2016) [23]

Takedaetal.

(2006) [24]

Trivedietal.

(2014) [25]

Vincentetal.

(2018) [26]

Study design

appropriate to

objectives?

Objective: Common design:

Prevalence Cross sectional NA NA NA 0 0 NA 0 NA NA

Prognosis Cohort 0 NA NA NA NA NA NA NA NA

Treatment Controlled trial NA 0 NA NA NA 0 NA NA NA

Cause Cohort, case-control NA NA 0 NA NA NA NA 0 0

Study sample

representative?

Source of sample + + + + + + + + +

Sampling method + + + + + 0 + + +

Sample size + ++ + + + + + + ++

Entry criteria/exclusions 0 + 0 + + + ++ + +

Non-respondents NA NA NA NA NA NA NA NA NA

Control group

acceptable?

Deﬁnition of controls ++ 0 0 ++ ++ ++ ++ + ++

Source of controls + + + + + 0 + + +

Matching/randomisation ++ ++ + ++ ++ 0 + + +

Comparable characteristics ++ + + ++ ++ ++ 0 0 +

Quality of

measurements

and outcomes?

Validity + 0 0 + + 0 + 0 +

Reproducibility NA NA 0 0 0 0 0 0 0

Blindness NA NA NA NA NA + NA NA NA

Quality control + 0 0 ++ ++ 0 0 0 0

Completeness?

Compliance NA NA NA NA NA NA NA NA NA

Drop outs NA NA NA NA NA NA NA NA NA

Deaths NA NA NA NA NA NA NA NA NA

Missing data 0 0 0 0 0 0 0 0 0

Distorting

inﬂuences?

Extraneous treatments NA NA NA NA NA NA NA NA NA

Contamination NA NA NA NA NA NA NA NA NA

Changes over time NA NA NA NA NA NA NA NA NA

Confounding factors ++ 0 + ++ ++ 0 0 + 0

Distortion reduced by analysis ++ 0 ++ ++ ++ 0 0 + 0

Summary

questions

Bias - Are the results erroneously YES YES YES YES YES YES YES YES YES

biased in a certain direction?

Confounding - Are the any serious YES NO NO YES YES NO NO NO NO

Confounding or other distorting

inﬂuence?

Chance - Is it likely that the results YES YES YES YES YES YES YES YES YES

ocurred by chance?

Note: NA: not applicable; +: Minor problem; ++: Major problem; 0: No problem was assigned.

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Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

number of individuals). Publication bias was

considered unsuspected, and since the evidence

was affected by some of the previously mentioned

criteria, no item was considered to raise the

certainty. The judgments issued for the evaluation

of the certainty of the evidence for the outcomes

involving more than one study are presented in

Table II.

DISCUSSION

This systematic review aimed to synthesize

the scientic evidence of studies on the association

of OS biomarkers in individuals with T2DM

with and without periodontitis. This systematic

review was based on 9 not-sound studies and

indicates that high levels of oxidizing agents and

low concentration of antioxidants in T2DM are

related with the presence of periodontitis when

compared to individuals without periodontitis.

This is the rst systematic review with quality

assessment on this topic.

After ling in PROSPERO, studies selection,

and full reading, it was observed that some

studies had diagnostic criteria for periodontitis of

CAL ≥3mm [27,28] and, if they were excluded,

some important data would be missing for the

systematic review. So we decided to include

them, considering that the registration of the

present study was made based on the APP

classification [29]. According to the actual

Classification of Periodontal Diseases and

Conditions [30], taking into consideration CAL,

periodontitis is characterized by: CAL ≥3mm in

interproximal areas of at least 2 non-adjacent

teeth or in buccal or lingual/palatal, without it

being due to: 1) traumatic gingival recession;

2) dental caries extending to the cervical area

of the tooth; 3) presence of insertion loss on the

distal face of a second molar and associated with

poor positioning or extraction of the third molar;

4) endoperiodontal lesion draining through the

marginal periodontium; or 5) occurrence of

vertical root fracture. Thus, this parameter had

to be changed for articles selection.

Data show that patients with T2DM and

periodontitis have impaired glycemic status and

exhibit signicantly lowered B-cell function and

higher levels of HbA1c and fasting glucose than

matched patients without periodontitis [20].

Those chronic inflammatory conditions are

generally thought to be associated with increased

OS with phagocytes, particularly neutrophils.

Those cells are implicated in periodontal disease

pathogenesis as they induce the generation

of an oxidative burst during phagocytosis

and killing [26]. On the other hand, ROS are

associated with microvascular complications of

T2DM. It is also known that severe periodontal

disease can lead to endothelial dysfunction,

which justify the assessment of effect of coexisting

T2DM and periodontitis on the levels of OS

markers [20].

Periodontitis increases plasma biomarkers

of OS as evidenced by the nding of reduced

SMAC combined with increased levels of protein

CO, which is a marker of protein oxidation.

In the co-occurrence of T2DM and periodontitis,

there is higher alterations in levels of these OS

Table III - Assessment of the certainty of evidence (GRADE)

Certainty assessment

Certainty

N° of

datasets

Design of

the studies Risk of bias Inconsistency Indirectness Imprecision Other

considerations

Malondialdehyde

2 Observational* SeriousaSeriousbNot serious SeriouscNone ⨁◯◯◯

VERY LOW

Total antioxidant capacity

2 Observational SeriousaSeriousbNot serious SeriouscNone ⨁◯◯◯

VERY LOW

Magnesium

2 Observational* SeriousaNot serious Not serious SeriouscNone ⨁◯◯◯

VERY LOW

* Baseline data from intervention studies were considered. a. The certainty of the evidence was downgraded in one level because the

studies had important methodological limitations and it is likely that they may have altered the results. b. The certainty of the evidence was

downgraded by one level because the studies reported diﬀerent eﬀects. c. The certainty of the evidence was downgraded by one level due to

the reduced number of individuals considered in the synthesis (less than the threshold of 400 recommended by GRADE).

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

biomarkers. This suggests signs of enhanced OS

in serum of T2DM with periodontitis individuals,

showing that periodontitis has a negative effect

on the already compromised oxidative status of

T2DM patients [28]. Vincent et al. [26] shown

high levels of TOS in T2DM with periodontitis

group when compared to periodontitis without

T2DM encouraging the aforementioned data.

Role of nitric oxide system in T2DM is few

studied and controversial to scientics research,

demonstrating higher level, low level, or no

change. In chronic inammatory processes, where

activity of PMNs, macrophages, and endothelial

cells is elevated, such as in periodontitis, the

expression of iNOS is increased. The positive

relationship between iNOS, inflammatory

cytokines and other mediators reveals an immune-

activated state due higher NO production. Thus,

it might be higher in individuals with T2DM and

chronic periodontitis when compared to without

periodontitis cells [20].

MDA is the major and commonly

studied product of polyunsaturated fatty acid

peroxidation that is shown to rise following OS.

Glycated collagen has been shown a role in lipid

glycoxidation compared to normal collagen that

results in increased MDA in serum and tissues

of diabetic subjects [20]. In T2DM individuals

with periodontitis, MDA was reported to be

higher when compared to individuals without

periodontitis [23].

It was reported that TAC levels in GCF was

lower in patients with T2DM and periodontitis,

compared to individual with only T2DM.

The decrease in TAC levels reported could be

attributed to elevated ROS levels that must be

neutralize causing depletion of antioxidants,

in addition to presence hyperglycemia, which

is the primary cause of inammation in T2DM

individuals [24]. In another study, the comparison

of the TAC in saliva revealed lower antioxidant

levels in T2DM with periodontitis compared to

non-diabetic individuals with periodontitis [26].

Excessive glucose levels induce free radical

production and enhance OS by increased

formation of AGEs. These pathologic mechanisms

in T2DM with the preexisting periodontal

disease could be responsible for exacerbated

periodontal destruction seen in diabetics [24].

Takeda et al. [24] reported that AGEs were

signicantly related to periodontal deterioration

associated with T2DM, showing that their level

may be a suitable biomarker to reect periodontal

status in those patients.

Micronutrients are regulated by homeostatic

processes and function as antioxidant in the

control of damage caused by ROS [31]. Calcium

and iron play an essential role in regeneration,

for coping with OS and for an adequate immune

response, but dysregulation these micronutrients

(high levels) in the serum may promote the

development and progression of oxidative

stress [32]. It has been reported that the mean

calcium level in T2DM with periodontitis

individuals was significantly higher when

compared to systemically and periodontally

healthy individuals. It was also demonstrated

that an increased serum iron levels in T2DM with

periodontitis can act as pro-oxidant agents, which

are responsible for the formation of ROS [28].

Additionally, it was reported that T2DM

with periodontitis had lower zinc levels

than those individuals with T2DM without

periodontitis [21,25]. Zinc deciency promotes

the activation of N-methyl-D-aspartate (NMDA)

receptors, which increase the intracellular

concentration of calcium. In conditions where

zinc is decient, the NADPH oxidase enzymes

and nitric oxide synthase are activated, favoring

the production of reactive species of oxygen and

nitrogen [33].

Being an essential dietary nutrient, vitamin

C is important for many enzyme reactions.

It is an electron donor, and this property might

account for all its known functions, such as water-

soluble antioxidant in humans and protects from

oxidative damage under conditions of increasing

oxygen concentrations and apoptosis [34].

Pushpa Rani et al. suggests that decreased

vitamin C levels are associated with an increased

risk for the development of oxidative stress

in type 2 diabetes mellitus with periodontitis,

considering that the antioxidant activity of

ascorbic acid involves transfer of hydrogen rather

than an electron [25].

Magnesium it is a cofactor of several

antioxidant enzymes, including SOD, one of

the most important antioxidant enzymes [35]

and it has been demonstrated that magnesium

supplement has a beneficial effect on

periodontitis [36]. Furthermore, low magnesium

levels may favor the onset and progression of

T2DM, frequently seen in these patients [21,37].

Pushpa Rani [28]demonstrated that magnesium

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Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

mean levels in T2DM without periodontitis and

non-T2DM with periodontitis individuals were

greater than the ones found for T2DM with

periodontitis individuals and those ndings were

corroborated in another investigation [22].

The enzyme SOD is a key antioxidant

that catalyzes the dismutation of superoxide

(O2

-), generating hydrogen peroxide (H2O2).

The products CAT, GRd and GPx accelerate

H2O2 reduction in water [38]. Trivedi et al.

demonstrated that SOD, CAT and GRd activities

were higher in T2DM with periodontitis group

compared with T2DM without periodontitis

group. In periodontitis, SOD, CAT and GRd levels

are low due antioxidant depletion, to ongoing

free radical activity and destruction of protective

antioxidant species [23].

Clinical investigations must always focus on

correct matching for gender, age, and periodontal

status to reduce potential confounding

factors. Latha et al. [20], Pendyala et al. [26],

Takeda et al. [27] and Trivedi et al. [25] follow

these restrictions and the distribution of age and

gender was similar between groups, suggesting

that they were well matched. Thus, their results

might present greater validity and relatively

fewer confounding factors.

The analysis of non-randomized clinical trials

properly reported most of the criteria analyzed

in Summary questions (Bias, Confounding

and Chance) as present in 3 studies. In six

studies [20,22-24,26,27] confounding factors

were no detected. Shetty et al. [23] dened their

study as a randomized clinical trial, but it has

four groups (i.e., T2DM with periodontitis,

T2DM without Periodontitis, non-T2DM with

periodontitis, and systemically and periodontally

healthy) with distinct interventions (scaling and

root planning, and oral hygiene instructions),

and there is no random allocation of groups/

treatment. In summary, their results are

inconsistent and the evidence regarding OS

biomarkers, T2DM and periodontitis relationship

is lacking strong evidence.

Of the nine included studies, three assessed

biomarkers in saliva and this suggests its

potential relevance as an important alternative

biological uid [20,23,26]. Included studies in

this systematic review are following the expected

direction of the association, that there is difference

in OS levels between T2DM individuals with and

without periodontitis. These studies reported the

relationship between high levels of oxidizing

compounds or decrease of antioxidants in T2DM

with periodontitis individuals, when compared

to T2DM without periodontitis individuals.

Therefore, these data suggest that periodontitis

has a negative influence on OS in T2DM and

recognize that an early diagnosis of periodontitis

may be important for prevention of a negative

impact on the OS biomarkers.

However, considering the few studies found,

the methodological aws, few markers studied

and absence homogeneity in the evaluation of

redox balance markers, as well as, the very low

certainty of the evidence among included studies,

ie there was no sound studies included in this

systematic review, these results should be viewed

with caution. Therefore, it was not possible to

determine whether there are or not differences

in the oxidative stress levels in individuals with

T2DM associated with periodontitis and further

prospective observational and interventional

studies are recommended.

Acknowledgements

The authors thank the Federal University of

Rio de Janeiro (UFRJ), Brazil. for support during

the development and writing of these manuscript.

Author’s Contributions

WJML: Conceptualization, Validation,

Formal Analysis, Investigation, Methodology,

Resources, Data Curation, Writing – Original Draft

Preparation. CCM: Conceptualization, Validation,

Investigation, Methodology, Visualization,

Writing – Review & Editing. GAMV: Validation,

Formal analysis, Methodology, Visualization,

Writing - Review & Editing. DM: Methodology,

Visualization, Data Curation, Writing – Review &

Editing. LCM: Conceptualization; Formal Analysis,

Funding Acquisition, Methodology, Resources,

Visualization, Writing – Review & Editing.

MCMB: Conceptualization, Data Curation,

Formal Analysis; Investigation; Methodology,

Supervision, Writing – Review & Editing.

CMSB: Conceptualization, Funding Acquisition,

Investigation, Methodology, Supervision,

Validation, Visualization, Writing – Original

Draft Preparation; Writing – Review & Editing,

Project Administration. CS: Data Curation;

Formal Analysis, Investigation, Methodology,

Project Administration, Supervision, Validation,

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Visualization, Writing – Original Draft

Preparation, Writing – Review & Editing, Project

Administration.

Conicts of Interest

The authors have no proprietary, nancial,

or other personal interest of any nature or kind

in any product, service, and/or company that is

presented in this article.

Funding

The work was supported by Coordenação

de Aperfeiçoamento de Pessoal de Nível Superior

(CAPES) and Fundação de Amparo à Pesquisa do

Estado do Rio de Janeiro (FAPERJ).

Regulatory Statement

This systematic review was conducted

through a search strategy in electronic databases.

The search was restricted to publications in peer-

reviewed journals, in which approval for ethics

committee were obtained in their original work.

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Walder Jansen de Mello Lobão

(Corresponding address)

Departamento de Clínica Odontológica, Divisão de Periodontia, Faculdade

de Odontologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ,

Brazil.

Email: walderjansen@hotmail.com

Date submitted: 2023 Nov 21

Accept submission: 2024 June 27

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Appendix 1. Electronic database and search strategy

MEDLINE

(Diabetes Mellitus[Mesh] OR Diabetes Mellitus[Tiab] OR Diabetes Mellitus, Type 2[Mesh] OR Diabetes

Mellitus Non Insulin Dependent[Tiab] OR Diabetes Mellitus Stable[Tiab] OR NIDDM[Tiab] OR MODY[Tiab]

OR Maturity Onset Diabetes[Tiab] OR Type 2 Diabetes[Tiab] OR Diabetes Type 2[Tiab]) AND (Periodontal

Diseases[Mesh] OR Periodontal Disease*[Tiab] OR Periodontitis[Mesh] OR Periodont*[Tiab] OR Aggres-

sive Periodontitis[Mesh] OR Aggressive Periodont*[Tiab] OR Chronic Periodontitis[Mesh] OR Chronic

Periodont*[Tiab]) AND (Oxidative Stress[Mesh] OR Oxidative Stress*[Tiab] OR Antioxidants[Mesh]

OR Antioxidant*[Tiab] OR Antioxidant eﬀect*[Tiab] OR Free radicals[Mesh] OR Free radicals[Tiab] OR

Oxidants[Mesh] OR Oxidant*[Tiab] OR Oxidizing Agents[Tiab])

SCOPUS

TITLE-ABS-KEY((“Diabetes Mellitus” OR “Diabetes Mellitus, Type 2” OR “Diabetes Mellitus Non Insulin Dependent” OR

“Diabetes Mellitus Stable” OR NIDDM OR MODY OR “Maturity Onset Diabetes” OR “Type 2 Diabetes” OR “Diabetes

Type 2”) AND (Periodontal Disease* OR Periodont* OR Aggressive Periodont* OR Chronic Periodont*) AND (Oxidative

Stress* OR Antioxidant* OR Antioxidant eﬀect* OR “Free radicals” OR Oxidant* OR “Oxidizing Agents”))

WEB OF

SCIENCE

((“Diabetes Mellitus” OR “Diabetes Mellitus, Type 2” OR “Diabetes Mellitus Non Insulin Dependent” OR “Diabetes

Mellitus Stable” OR NIDDM OR MODY OR “Maturity Onset Diabetes” OR “Type 2 Diabetes” OR “Diabetes Type 2”) AND

(Periodontal Disease* OR Periodont* OR Aggressive Periodont* OR Chronic Periodont*) AND (Oxidative Stress* OR

Antioxidant* OR Antioxidant eﬀect* OR “Free radicals” OR Oxidant* OR “Oxidizing Agents”))

COCHRANE

#1 MeSH descriptor: [Diabetes Mellitus] explode all trees

#2 “Diabetes Mellitus”

#3 MeSH descriptor: [Diabetes Mellitus, Type 2] explode all trees

#4 (“Diabetes Mellitus Non Insulin Dependent” OR “Diabetes Mellitus Stable” OR NIDDM OR MODY OR “Maturity Onset

Diabetes” OR “Type 2 Diabetes” OR “Diabetes Type 2”)

#5 #1 OR #2 OR #3 OR #4

#6 MeSH descriptor: [Periodontal Diseases] explode all trees

#7 Periodontal disease*

#8 MeSH descriptor: [Periodontitis] explode all trees

#9 Periodont*

#10 MeSH descriptor: [Aggressive Periodontitis] explode all trees

#11 Aggressive Periodont*

#12 MeSH descriptor: [Chronic Periodontitis] explode all trees

#13 Chronic Periodont*

#14 #6 OR #7 OR #8 OR #9 OR #10 OR #11 OR #12 OR #13

#15 MeSH descriptor: [Oxidative Stress] explode all trees

#16 Oxidative Stress*

#17 MeSH descriptor: [Antioxidants] explode all trees

#18 (Antioxidant* OR Antioxidant eﬀect*)

#19 MeSH descriptor: [Free Radicals] explode all trees

#20 “Free radicals”

#21 MeSH descriptor: [Oxidants] explode all trees

#22 (Oxidant* OR “Oxidizing Agents”)

#23 #15 OR #16 OR #17 OR #18 OR #19 OR #20 OR #21 OR #22

#24 #5 AND #14 AND #23

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Appendix 1. Continued...

LILACS and

BBO

tw:(tw:((tw:((mh: “Diabetes Mellitus” OR mh: “Diabetes Mellitus, Type 2” OR “Diabetes Mellitus Tipo 2” OR “Diabetes

Mellitus Non Insulin Dependent” OR “Diabetes Mellitus não dependente de insulina” OR “Diabetes Mellitus Stable” OR

“Diabetes Mellitus estável” OR niddm OR dmndi OR mody OR “Maturity Onset Diabetes” OR “Diabetes com início na

maturidade” OR “Type 2 Diabetes” OR “Diabetes tipo 2” OR “Diabetes Type 2” OR “Tipo 2 Diabetes”) )) AND (tw:((mh:

“Periodontal Diseases” OR “doenças periodontais” OR “periodontal disease” OR “periodontal diseases” OR “doença

periodontal” OR “doenças periodontais” OR mh: periodontitis OR periodontite OR periodontitis OR periodontite OR

mh: “Aggressive Periodontitis” OR “Periodontite Agressiva” OR “Aggressive Periodontitis” OR “Periodontite Agressiva”

OR mh: “Chronic Periodontitis” OR “Periodontite Crônica” OR “Chronic Periodontitis” OR “Periodontite Crônica”) ))

AND (tw:((mh: “Oxidative Stress” OR “Estresse Oxidativo” OR oxidative stress* OR “Estresse Oxidativo” OR “Estresses

oxidativos” OR mh: antioxidants OR antioxidantes OR antioxidant OR antioxidants OR antioxidante OR “antioxidant

eﬀect” OR “Antioxidants eﬀects” OR “Efeito antioxidante” OR “Efeitos antioxidantes” OR mh: “Free radicals” OR

“Radicais livres” OR “Free radicals” OR “Radicais livres” OR mh: oxidants OR oxidantes OR oxidants OR oxidant OR

oxidante* OR “Oxidizing Agents” OR “ agentes oxidantes”)))) AND ( db:(“LILACS” OR “BBO”))) AND ( type:(“article”))

EMBASE

(‘diabetes mellitus’:ti,ab,kw OR ‘diabetes mellitus, type 2’:ti,ab,kw OR ‘diabetes mellitus non insulin dependent’:ti,ab,kw

OR ‘diabetes mellitus stable’:ti,ab,kw OR niddm:ti,ab,kw OR mody:ti,ab,kw OR ‘maturity onset diabetes’:ti,ab,kw OR

‘type 2 diabetes’:ti,ab,kw OR ‘diabetes type 2’:ti,ab,kw) AND (‘periodontal disease*’:ti,ab,kw OR periodont*:ti,ab,kw

OR ‘aggressive periodont*’:ti,ab,kw OR ‘chronic periodont*’:ti,ab,kw) AND (‘oxidative stress*’:ti,ab,kw OR

antioxidant*:ti,ab,kw OR ‘antioxidant eﬀect*’:ti,ab,kw OR ‘free radicals’:ti,ab,kw OR oxidant*:ti,ab,kw OR ‘oxidizing

agents’:ti,ab,kw)

OPEN GREY

Periodontitis and Diabetes and Antioxidants

Periodontitis and Diabetes and Free radicals

Periodontitis and Diabetes and Oxidants

Periodontitis and Diabetes and Oxidative Stress

Periodont* and Diabetes and Antioxidants

Periodont* and Diabetes and Free radicals

Periodont* and Diabetes and Oxidants

Periodont* and Diabetes and Antioxidants

Periodont* and Diabetes and Oxidative Stress

Periodont* and Diabetes and Antioxidant*

Periodont* and Diabetes and Oxidative Stress*

Periodontitis and Diabetes and Antioxidant*

Periodontitis and Diabetes and Oxidative Stress*

GOOGLE

SCHOLAR

Periodontitis and diabetes type 2 and oxidative stress

Periodontite e diabetes tipo 2 e estresse oxidativo

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Appendix 2. Criteria’s adopted to risk of bias classication (adapted from Fowkes

and Fulton [15])

Study design

appropriate to

objective?

Prevalence -

Cross-sectional 0 – if the study, or part of study, included in the present systematic review reported oxidative stress in type 2

diabetics with periodontitis and had a cross-sectional design

Prognosis -

Cohort 0 – if the study, or part of study, included in the present systematic review reported oxidative stress in type 2

diabetics with periodontitis and had a Cohort design

Treatment -

Controlled trial 0 - if the study, or part of study, included in the present systematic review evaluate some type of treatment

related periodontitis or type 2 diabetes mellitus and measurement oxidative stress levels and had a controlled

trial design

Cause - Cohort,

case-control,

cross-sectiona

0 - if the study, or part of study, included in the present systematic review evaluate some type of relationship

/ association / risk reported of oxidative stress alteration in type 2 diabetics with periodontitis had a cross-

sectional, case-control or cohort design, respectively.

Study sample

representative?

Source of

sample (0) case group was obtained from various referral hospital (multicentre).

(+) case group was composed of individuals from a reference center or referral hospital.

(++) case group was obtained from unspeciﬁed locations.

Sampling

method (0) probabilistic sampling (simple random, stratiﬁed, blocks).

(+) did not use any type of randomization, but authors of the present systematic review judged that could not

inﬂuence in outcome evaluation, as all eligible participants from a speciﬁc site/place were included.

(++) did not use any type of randomization, but authors of the present systematic review judged that could

inﬂuence in outcome evaluation by using a convenience sample.

Sample size (0) sample size calculation was described considering all variables and study groups.

(+) did not perform sample size calculation but had a representative sample, using a sample size equal or higher

than 97 subjects (median of samples from included studies).

(++) did not mention such sample size calculation or representative sample, using a sample size lower than 97

subjects (median of samples from included studies).

Inclusion/

exclusion

criteria

(0) Selection criteria properly established. Periodontitis: PBS≥ 4mm, NCI≥ 4mm, presence of bioﬁlm, bleeding on

probing (> 10%) and presence of suppuration. Examination performed by a single calibrated examiner or more

than one (calibrated), who underwent a complete periodontal examination (in the six sites of the teeth present),

using a standard probe for the diagnosis of periodontitis (North Carolina 15mm).

(+)Selection criteria established, but some criteria were not considered (do not mention one of the criteria for

diagnosing periodontitis previously shown or the examiner is not calibrated).

(++) Selection criteria loosely established or absence of two or more periodontitis selection criteria.

Non-

respondents N. A. - the authors of the present systematic review judged that the non-respondent’s rate could not inﬂuence in

outcome evaluation.

Control group

acceptable?

Deﬁnition of

controls (0) Selection criteria properly established. Absence of periodontitis: PBS≤ 3mm, NCI≤ 3mm, little or no bioﬁlm, no

or little bleeding on probing (<10%) and no suppuration. Examination performed by a single calibrated examiner

or more than one calibrated, who underwent a complete periodontal examination (at the six sites of the teeth

present), using a standard probe for the diagnosis of periodontitis (North Carolina 15mm).

(+) Selection criteria established, but some criteria were not considered (do not mention one of the criteria for

periodontal health shown previously).

(++) Selection criteria loosely established. Absence of two or more selection criteria for periodontal health.

Source of

controls (0) control group was obtained from various referral hospital (multicentre).

(+) control group was composed of individuals from a reference center or referral hospital.

(++) control group was obtained from unspeciﬁed locations.

Matching/

randomization (0) group control was paired according to gender, age and duration of diabetes.

Comparable

characteristics (+) only matched by two of the criteria mentioned above.

(++) control group was not paired.study mentioned that case and control groups were matching for sex, age and

general health.

(0) There is no diﬀerence between the groups regarding age, gender and duration of diabetes.

(+) the groups are diﬀerent only in relation to two criteria.

(++) the groups are diﬀerent in relation to age or duration of diabetes.

Quality of

measurements and

outcomes?

Validity (0) Use of the gold standard method for determining the biomarker

(+) adequate test, but it is not the gold standard.

(++) Test not suitable.

Reproducibility (0) An experienced and calibrated evaluator and that there was acceptable reproducibility in the measurement

of oxidative stress markers.

(+) a trained evaluator, but the study’s reproducibility analysis was not performed.

(++) an uncalibrated evaluator, but the study was not reproducible or was not even mentioned in the study.

Blindness (0) Researcher who collected and analyzed samples were blinded to the study group.

(+) Researcher who collected or analyzed the samples was blinded to the study group.

(++) There was no blinding in any phase of the study.

Quality control (0) Adequate acquisition, processing and storage of samples. Adequate description of the parameters used to

measure oxidative stress.

(+) one of the points described above was neglected or not mentioned.

(++) two or more points described above were neglected or not mentioned.

NA – Not applied.

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Completeness?

Compliance NA (question did not apply to study methodology)

Dropouts NA (question did not apply to study methodology)

Deaths NA (question did not apply to study methodology)

Missing data (0) The study reports the number of missing data (up to 30%) and the reasons. (or the absence of missing data).

(+) the number of missing data is reported without explaining the reasons (with up to 30% of the missing data).

(++) nothing is speciﬁed or there was a loss greater than 30%.

Distorting inﬂuences?

Extraneous

treatments NA (question did not apply to study methodology)

Contamination NA (question did not apply to study methodology)

Changes over

time NA (question did not apply to study methodology)

Confounding

factors (0) Presence of comorbidities: chronic kidney disease, high blood pressure, dyslipidemia, obesity and

immunosuppressed by medication. Other metabolic changes. Age and gender. Duration of diabetes.

(+) was assigned when 1 or 2 of these characteristics were present

(++) if there were 3 or more.

Distortion

reduced by

analysis

(0) Stratiﬁed data analysis was performed, or regression analysis considering possible confounding factors. Or,

there was no need due to the absence of confounding factors.

(+) adjustment of the analyzes was performed only in relation to some confounding factors.

(++) there were confounding factors, but this was not considered in the analyzes.

Summary Questions

Bias - Are

the results

erroneously

biased in

a certain

direction?

Yes / No

Confounding

- Are there

any serious

confounding

or other

distorting

inﬂuences?

Yes / No

Chance - Is

it likely that

the results

occurred by

chance?

Yes / No

NA – Not applied.

Appendix 2. Continued...

Braz Dent Sci 2024 Apr/June;27 (2): e4163

Lobão WJM et al. Is there a difference in the oxidative stress levels between type 2 diabetic individuals with and without periodontitis? Systematic review

Lobão WJM et al. Is there a diﬀerence in the oxidative stress levels between

type 2 diabetic individuals with and without periodontitis?

Systematic review

Appendix 3. Studies excluded and reason of the exclusion

Reason 1. Absence of group T2DM without Periodontitis

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2 diabetes: A randomized clinical trial. PLoS ONE 2017; 12(11):1-17.

13. Patil VS,etal. Chronic Periodontitis in Type 2 Diabetes Mellitus: Oxidative Stress as a Common Factor in Periodontal Tissue Injury. Journal of Clinical

and Diagnostic Research 2016; 10(4):12-16.

14. Pradeep AR,etal. 4-Hydroxy-2-nonenal, an oxidative stress marker in crevicular ﬂuid and serum in type 2 diabetes with chronic periodontitis. Contemp

Clin Dent. 2013; 4(3):281-285.

15. Sonoki, K,etal. Decreased Lipid Peroxidation Following Periodontal Therapy in Type 2 Diabetic Patients. J Periodontol. 2006; 77(11):1907-1913.

16. Thomas B,etal. A comparative evaluation of antioxidant enzymes and selenium in the serum of periodontitis patients with diabetes mellitus type 2.

Contemp Clin Dent. 2013; 4(2):176-180.

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COCHRANE

1. Gholinezhad H,etal. Using Ginger Supplement in Adjunct with Non-surgical Periodontal Therapy Improves Metabolic and Periodontal Parameters

in Patients with Type 2 Diabetes Mellitus (DM) and Chronic Periodontitis. A Double-Blind, Placebo-Controlled Trial. Journal of Herbal Medicine 2019;

20(100315).

VHL

1. Navarro MLR,etal. Niveles de proteína carbonilada y capacidad antioxidante total en pacientes con diabetes mellitus tipo 2 de reciente diagnóstico y

enfermedad periodontal. Revista ADM 2019; 76 (4): 208-213.

2. Penagos AGV, Núñez VMM. Relación del estrés oxidativo con la enfermedad periodontal en adultos mayores con diabetes mellitus tipo 2. Revista ADM

2006; 63 (5):189-194.

Reason 2. research participants with more than one systemic disease

WEB OF SCIENCE

1. Bastos AS. Lipid Peroxidation Is Associated with the Severity of Periodontal Disease and Local Inﬂammatory Markers in Patients with Type 2 Diabetes. J

Clin Endocrinol Metab 2012; 97 (8):1353-1362.

Reason 3. summary study of a larger included in this systematic review

EMBASE

1. Pushparani DS. Serum zinc and iron level in type 2 diabetes mellitus with periodontitis. International Journal of PharmTech Research, 2015; 7 (1):165-171.