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International Journal of
Environmental Research
and Public Health
Review
Oral Health Status and Need for Oral Care in an
Aging Population: A Systematic Review
Dorina Lauritano 1, *,†, Giulia Moreo 1,†, Fedora Della Vella 2, Dario Di Stasio 3,
Francesco Carinci 4, Alberta Lucchese 3and Massimo Petruzzi 2
1Department of Medicine and Surgery, Centre of Neuroscience of Milan, University of Milano-Bicocca,
20126 Milan, Italy; moreo.giulia@gmail.com
2Interdisciplinary Department of Medicine, University of Bari, 70121 Bari, Italy;
dellavellaf@gmail.com (F.D.V.); massimo.petruzzi@uniba.it (M.P.)
3Multidisciplinary Department of Medical and Dental Specialties, University of Campania-Luigi Vanvitelli,
80138 Naples, Italy; dario.distasio@unicampania.it (D.D.S.); alberta.lucchese@unicampania.it (A.L.)
4
Department of Morphology, Surgery and Experimental medicine, University of Ferrara, 44121 Ferrara, Italy;
crc@unife.it
*Correspondence: dorina.lauritano@unimib.it; Tel.: +39-3356790163
†These authors contribute equally to this work.
Received: 3 November 2019; Accepted: 10 November 2019; Published: 18 November 2019
Abstract:
Background. The world population is aging. This phenomenon is accompanied by
an increase in the number of elderly with dementia, whose oral hygiene care is a challenge. Objective.
This paper presents a literature review of oral health status and the need for oral care in people with
dementia, as compared to people without dementia and also of the relationship between periodontal
disease and cognitive impairment. Methods. A systematic review was conducted in PubMed,
CINAHL, and the Cochrane Library. Fifty-six articles met the inclusion criteria and were consequently
included for quality assessment and data extraction. Results. No significant differences were found
between both groups with regard to the number of present teeth, DMFT Index, edentulousness/use of
denture, and orofacial pain. Coronal/root caries and retained roots were more common in people
with dementia than in those without dementia. Most of the participants with dementia presented
gingival bleeding or inflammation and they suffered from the periodontal disease more than people
without dementia. Conclusions. Poor oral health is a common condition among the elderly with
dementia. The education process of caregivers might improve the oral health status of people with
dementia. Finally, periodontal disease might contribute to the onset or progression of dementia.
Keywords:
oral health; aging population; oral disease; association with periodontal disease; oral care
need; oral care strategies
1. Introduction
The transition from high to low mortality and fertility that accompanied the socioeconomic
development of this century has meant a shift in the leading causes of disease and death and an increase
of general health problems [1].
As a consequence, a decline of the oral health conditions of the elderly, such as dental caries and
periodontal disease, is to be expected [
2
]. Poor oral health is more common in the elderly suffering
from dementia, a disorder that will become prevalent with advancing age of the world population.
Several studies analyzed the relationship between poor oral health and cognitive impairment, which
suggests that cognitive decline might negatively impact oral health and also that poor oral health might
lead to cognitive decline via specific biological mechanisms [
3
]. Conversely, in a recent systematic
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Int. J. Environ. Res. Public Health 2019,16, 4558 2 of 23
review by Wu et al. it has been argued that, according to some studies, it is unclear how or whether
oral health conditions and cognitive status are related [4].
In cognitively impaired elderly, the increased incidence of oral disease might be favored by their
general conditions: cognitive decline, loss of memory, learning disabilities, attention deficits, and
motor skills deterioration, which result in reduced ability to perform routine oral care [
5
]. A frequent
difficulty among these subjects is also the refusal of oral hygiene care, not opening their mouth, using
abusive language, or being aggressive.
Even in the early stages of the disease progression, the elderly with dementia have a reduced
salivary flow, which can lead not only to a higher prevalence of dental caries [
6
], but also to difficulties
with eating and swallowing, which compromises communication skills [
7
]. The study by Silva et al.
demonstrated that people with dementia living in Australians nursing homes have higher levels of
untreated coronal and root caries, due to their cognitive condition and to poor access to professional
services [8].
Periodontal disease is higher in the elderly with dementia than in normal cognitive individuals
and the periodontal status worsens with the cognitive impairment progression [
9
]. Evidence of the
association between periodontal disease and dementia has been demonstrated: periodontal disease is
an inflammatory illness that affects the mouth and it could systemically affect individuals who are
vulnerable to dementia and contribute to its pathogenesis [10].
Oral mucosal lesions are frequent in the elderly: the most common denture-related lesions are
stomatitis, angular cheilitis, ulcers, hyperplasia, or candidosis. Reduced cognitive independence and
decline in self-care, due to dementia, delirium, and social isolation, and it could make oral mucosal
condition even worse [11].
Oral health problems in non-verbal individuals could negatively impact life quality, since they
cannot communicate their pain and discomfort. On this topic, the study by Merlijn W. de Vries et al.
proved the reliability of “the Orofacial Pain Scale for Non-Verbal Individuals” (OPS-NVI) and its
psychometric evaluation (Delwel et al. 2018), to establish the presence of pain-related nonverbal
communication, such as facial expressions, body movements, and vocal expressions [12].
1.1. Rationale of the Systematic Review
The most important risk factor that is associated with the onset of dementia is age and in an
aging society, the impact of the phenomenon will be of alarming dimensions. Dementia reduces the
quality of life of patients also with regard to oral health. It has been demonstrated that oral health of
the elderly with dementia is poorer than oral health in people with normal cognitive function [
13
,
14
].
However, it is currently unclear how or whether oral health and cognitive status are related [
15
,
16
].
This study is aimed at reviewing literature, in order to evaluate oral health status in elderly with
dementia, while comparing the data with those of elderly without dementia and to establish and
assess the need of specific oral care strategies, which could improve their quality of life. This research
was also conducted to review the available data regarding the influence of periodontal disease on the
progression of cognitive impairment.
1.2. Objectives
The purpose of this systematic review was to examine studies about oral health in elderly with
and without dementia, focusing the research on coronal and roots caries, number of remained teeth
and retained roots, Decayed Missing Filled Index, periodontal disease, utilization of dentures, salivary
flow, oral hygiene, oral mucosal lesions, orofacial pain, and on the analysis of periodontal disease as
a potential risk factor for dementia.
This study reviewed cohort, case-control, cross-sectional studies, and randomized controlled
clinical trials in order to examine oral health comparing the elderly with and without dementia.
Inclusion criteria of participants were a diagnosis of dementia and the availability of data related to
their oral health.
Int. J. Environ. Res. Public Health 2019,16, 4558 3 of 23
1.3. Clinical Question (PICO):
•P: A population of participants with diagnosis of dementia aged 60 years or older
•
I: Analysis of the oral health status and of the association between periodontal disease and dementia
•C: Comparison between oral health of elderly with and without dementia
•
O: Prevalence of oral disease (affecting hard and soft tissues) in elderly with dementia compared
to those without dementia, to define their need of oral care. Role of tooth loss due to periodontal
disease in the onset/progression of dementia.
2. Material and Methods
2.1. Protocol and Registration
Methods and inclusion criteria were selected following the PRISMA statement [
17
], which offers
a protocol with respect to the reference items that were included in this systematic review.
2.2. Eligibility Criteria
Inclusion and Exclusion Criteria
In this systematic review, all of the articles concerning oral health in the elderly with dementia
meeting the following requirements were included:
•Participants must have been diagnosed with dementia
•Quantitative data about oral health problems
•Participants had to be available
•Participants had to be 60 years or older
•Cohort, case-control, cross-sectional studies, and clinical trial were considered
The exclusion criteria were as follows:
•Case report and reviews
•No quantitative data available
•Age of participants below 60 years
2.2.1. Search
An electronic research was conducted to identify relevant studies that have been published
within 2019, but no restrictions were imposed with regard to language of the primary studies or
methodology. The following electronic databases were used: PubMed, CINAHL, and Cochrane Library.
The keywords used were the same for all three databases and they were combined with the Boolean
term “AND”: “oral health”, “aging population”, “oral disease”, “association with periodontal disease”
and “OR”: “oral care need”, and “oral care strategies”. The research was completed on May 2019.
2.2.2. Study Selection
Two researchers (G.M., D.L.) independently analyzed the title, abstract, and full text of each
English article to identify those that were eligible for the systematic review, according to the inclusion
and exclusion criteria established above. Disagreements between reviewers were resolved by consensus.
Articles that were published in other languages were assessed by a native speaker specialized in
medical language. Articles in which the diagnosis of dementia was not defined or quantitative data
were not available were excluded.
2.2.3. Data Collection Process
Two reviewers (G.M., D.L.) extracted the data, who also checked their methodological and clinical
heterogeneity (D.L.). The information extracted from each article were as follows: study design (cohort,
Int. J. Environ. Res. Public Health 2019,16, 4558 4 of 23
case-control, cross-sectional studies, or randomized clinical trial), participants characteristics, such as
age and diagnosis of dementia, and quantitative data on participants (outcome measures), including the
number of teeth present, number of retained roots, DMFT Index (Decayed Missing Filled Teeth Index),
edentulousness and dentures, coronal and root caries, periodontal health, and its association with the
onset or progression of dementia, oral mucosal disease, salivary flow, orofacial pain, oral hygiene, and
need for dental treatment. Means and percentages were used for the principal outcome measures.
2.2.4. Quality assessment
Newcastle-Ottawa scale (NOS) [
18
] was used to assess the quality of the studies (Tables 1–4).
The highest score was 9 and the lowest one was 1 (average score was 5.5 or cohort studies, 6.1 for
case-control studies, 4.6 for cross-sectional studies, and 5.5 for RCT). Most articles used the standardized
method to examine oral health and the examination was considered to be adequate if a dentist performed
it. With regard to “Comparability”, 30 of all the studies controlled for age or gender or both and in the
case-control, cross-sectional studies, and RCT only 5 (1.98% of the non-cohort studies) described the
non-response rate [
14
,
19
,
20
]. In almost all studies, the duration of follow-up period was longer than
three months. The evaluated quality parameters are shown in Additional file 1–4.
Table 1. Quality assessment for cohort studies (Additional file 1).
Cohort Studies Representativeness
of Exposed Cohort
Selection of
Non Exposed
Cohort
Ascertainment
of Exposure
Demonstration
Outcome Not
Present at Start
of Study
Comparability Outcome Total
Chalmers et al.
2002 [21]+− − − ++ ++−5
Chalmers et al.
2003 [13]+− − + ++ +++ 7
Chalmers et al.
2004 [22]+− − − − ++−3
Chen et al. 2010
[23]+ + + − − +++ 5
De Souza Rolim
et al. 2014 [24]+−+− − +−− 3
Dintica et al.
2018 [25]+−+ + ++ +++ 8
Ellefsen et al.
2009 [26]+ + + −++ ++−7
Hatipoglu et al.
2011 [27]− − − +−++ 3
Hoben et al.
2016 [28]+−+−+−++ 5
Jones et al. 1993
[29]+− − + ++ ++−6
Kato et al. 2019
[30]+−+ + +− −++ 6
Ide et al. 2016
[31]− − + + +−+++ 6
Lee et al. 2017
[10]+ + + −++ +++ 8
Ship and
Puckett 1994
[32]
+ + + −+−++−6
Sumi et al. 2012
[33]+−+− − ++ 4
Takeuchi et al.
2017 [34]+−+−++ +++ 7
Yoo et al. 2019
[35]+−+ + ++ ++−7
Zenthofer et al.
2014 [36]− − + + −+++ 5
Zenthofer et al.
2016 [37]+ + + + ++ +++ 5
+ = star assigned; −=star not assigned.
Int. J. Environ. Res. Public Health 2019,16, 4558 5 of 23
Table 2. Quality assessment for case-control studies (Additional file 2).
Case-Control
Studies
Definition
of Cases
Representativeness
of Cases
Selection of
Controls
Definition of
Controls Comparability Exposure Total
Chu et al. 2015 [38]−+−+ ++ +−− 5
De Souza Rolim et
al. 2014 [39]+ + + + ++ ++−8
Gil–Montoya et al.
2017 [14]+ + −+ ++ −++ 7
Hoeksema et al.
2016 [19]+ + −+− −++ 5
Kossioni et al. 2012
[40]+ + − − ++ ++−6
Leal et al. 2010 [41]−+−+− −++ 4
Nordenram et al.
1996 [42]+ + + + ++ ++−8
Warren et al. 1997
[43]+ + − − ++ +++ 7
Zenthofer et al.
2017 [44]+ + + −++ −−+6
+ = star assigned; −=star not assigned.
Table 3. Quality assessment for cross-sectional studies (Additional file 3).
Cross-Sectional
Studies
Representativeness
of the Sample
Sample
Size
Non-
Respondents
Ascertainment
of the Exposure Comparability Outcome Total
Adam et al. 2006 [45]−+ + − − +−3
Bomfin et al. 2013 [46]− − +− − − 1
Chalmers et al. 2002
[47]−+ + − − ++ 4
Chapman et al. 1991
[48]−+− − − +−− 2
Chen et al. 2013 [49]+ + + + −++−6
Chen et al. 2013-2015
[50,51]+ + + + − −+5
Cohen -Mansfield 2002
[52]− − − − − +−− 1
Delwel et al. 2019 [53]+ + + + ++ +++ 9
Ellefsen et al. 2008-2012
[54,55]+ + + −++ ++−7
Elsig et. Al. 2015 [56]+ + + − − ++−5
Eshkoor et al. 2014 [57]−+− − − — 1
Gil-Montoya et al. 2016
[58]+ + + + −++ 6
Kossioni et al. 2013 [59]+−+−++ −+−5
Furuta et al. 2013 [60]−+− − ++ ++−5
Hopcraft et al. 2012 [
61
]
−+ + − − ++−4
Lee et al. 2013 [62]+− − + +−++ 5
Luo et al. 2015 [20]+ + + + −+−++ 7
Minakuchi et al. 2006
[63]+ + −+ +−++−6
Philip et al. 2012 [64]− − − +−++−3
Ribeiro et al. 2012 [65]+ + − − ++−5
Srilapanan et al. 2013
[66]−+− − − +−− 2
Syrjala et al. 2012 [67]+ + + + ++ ++−8
Tiisanoja et al. 2018 [
68
]
−+−+ + ++ 5
+ = star assigned; −=star not assigned.
Table 4. Quality assessment for RCT (Additional file 4).
Randomized Clinical
Trial Definition Representativeness
of Cases
Selection of
Controls
Definition of
Controls Comparability Exposure Total
Fjeld et al. 2014 [69]+−+ + +++ 6
Zenthofer et al. 2016 [44]+ + − − ++ +−− 5
+ = star assigned; −=star not assigned.
Int. J. Environ. Res. Public Health 2019,16, 4558 6 of 23
3. Results
3.1. Study Selection and Characteristics
A total of 922 studies that were published between 1990 and 2019 were identified from database
searches. Among these articles, after examining titles and abstracts and the full texts of the remaining,
only 56 met the inclusion criteria and were consequently included for quality assessment and data
extraction. One study was added after scanning the reference list of the included articles [
39
]. All of the
studies were analyzed with regard to quality while using the Newcastle-Ottawa Scale (NOS). Figure 1
shows the flow chart of publication assessment.
Int. J. Environ. Res. Public Health 2019, 16, x FOR PEER REVIEW 7 of 25
the studies were analyzed with regard to quality while using the Newcastle-Ottawa Scale (NOS).
Figure 1 shows the flow chart of publication assessment.
Figure 1. PRISMA flow diagram.
The detailed characteristics about the 56 included studies are presented in Table 5, and Table 6,
with reference to author and year of publication, study design, case and controls, mean age of
participants, dementia measure, and measure of oral health. This review included 19 cohort studies,
9 case-control-studies, 26 cross-sectional studies, and two randomized clinical trials. Almost all of the
articles were in English, except for Sumi et al. article, which was written in Japanese [33]. A native
Japanese speaker, who extracted the data included in the review, examined this article.
The studies that were selected for the review included in total 8466 participants with dementia
and 6797 participants without dementia. In particular, selected studies regarding the association
between periodontal disease and dementia included 4698 participants with periodontal disease or
history of teeth extraction, 3132 elderly without periodontal disease, 60 subjects with dementia, and
2885 without dementia. In the included studies, the diagnosis of dementia was performed while using
DSM-III and IV [70], ICD-9 and 10 (International Classification of Disease [71]), NINCDS-ADRDA
(National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s
disease and Related Disorders Association [72]), Minimental State examination [73] (MMSE), and
other additional measures (e.g., computed tomography, magnetic resonance imaging, CDR [74]).
722 records selected after database
searching in PubMed, CINAHL,
722 records screened and assessed
for eligibility
666 records excluded:
Title, abstract, year of
publication
No full text
Study design
No useable data
56 studies included in the
systematic review
19
cohort
9
Case-control
26
Cross-sectional
2
RCT
Figure 1. PRISMA flow diagram.
The detailed characteristics about the 56 included studies are presented in Table 5, and Table 6,
with reference to author and year of publication, study design, case and controls, mean age of
participants, dementia measure, and measure of oral health. This review included 19 cohort studies,
9 case-control-studies, 26 cross-sectional studies, and two randomized clinical trials. Almost all of the
articles were in English, except for Sumi et al. article, which was written in Japanese [
33
]. A native
Japanese speaker, who extracted the data included in the review, examined this article.
The studies that were selected for the review included in total 8466 participants with dementia and
6797 participants without dementia. In particular, selected studies regarding the association between
periodontal disease and dementia included 4698 participants with periodontal disease or history of
teeth extraction, 3132 elderly without periodontal disease, 60 subjects with dementia, and 2885 without
dementia. In the included studies, the diagnosis of dementia was performed while using DSM-III
and IV [
70
], ICD-9 and 10 (International Classification of Disease [
71
]), NINCDS-ADRDA (National
Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s disease and
Int. J. Environ. Res. Public Health 2019,16, 4558 7 of 23
Related Disorders Association [
72
]), Minimental State examination [
73
] (MMSE), and other additional
measures (e.g., computed tomography, magnetic resonance imaging, CDR [74]).
Table 5.
List of studies about coronal/root caries, number of remained teeth/retained roots, DMFT,
periodontal disease, utilization of dentures, salivary flow, oral hygiene, and oral mucosal lesions in
elderly with and without dementia.
Study Design Dementia
Group Mean Age Control
Group Mean Age Dementia and Oral
Health Measure
Adam et al. 2006
[45]Cross-sectional 81 80.8 54 85.5
Abbreviated Mental
Test.
Orofacial pain,
dentures,
edentulousness,
DMFT, Debris Index
Bonfim et al.
2013 [46]Cross-sectional ? ? ? ?
MMSE, chart, ADL.
Number of present
teeth, dentures
Chalmers et al.
2002 [21]Cohort 116 91: <79 years
25: 80+years 116 91: <79 years
25: 80+years
MMSE.
Number of present
teeth, DMFT, root
caries, Plaque Index
Chalmers et al.
2002 [47]Cross-sectional 224 83.2 0 −
MMSE.
Number of present
teeth, DMFT,
dentures, dental
habits, coronal and
root caries, retained
roots
Chalmers et al.
2003 [13]Cohort 103 82: <79 years
21:80+years 113 88:<79 years
25:80+years
MMSE.
Number of present
teeth, DMFT, coronal
and root caries,
Plaque Index
Chalmers et al.
2004 [22]Cohort 224 83.2 0 −
MMSE.
Orofacial pain,
number of present
teeth, DMFT, dental
habits, number of
coronal and root
caries, retained roots
Chapman et al.
1991 [48]Cross-sectional 85 74.9 0 −
Dementia measure
not described.
Number of present
teeth, dentures,
DMFT, Presence of
deposits
Chen et al. 2010
[23]Cohort 119 81.5 372 73.8
Chart.
Present of calculus,
plaque and gingival
bleeding
Chen et al. 2013
[49]Cross-sectional
Community: 51
Assisted living:
18
NHR: 501
79.3 0 −
Chart, ICD-9.
Number of present
teeth, decay or
retained roots,
presence of calculus,
plaque and gingival
bleeding, need for
oral care
Chen et al. 2013
[50]Cross-sectional 501 82.6 199 76.1
Chart.
Presence of calculus,
plaque and gingival
bleeding
Chen et al. 2015
[51]Cross-sectional 46 79.3 138 71.6 Chart.
Need for oral care
Chu et al. 2015
[38]Case-control 59 79.8 59 79.8
Chart.
DMFT, Community
Periodontal Index,
Salivary flow
Int. J. Environ. Res. Public Health 2019,16, 4558 8 of 23
Table 5. Cont.
Study Design Dementia
Group Mean Age Control
Group Mean Age Dementia and Oral
Health Measure
Cohen-Mansfield
2002 [52]Cross-sectional 21 88.0 0 −
MMSE, MDS-COGS.
Number of broken or
fractured teeth, caries,
retained roots,
dentures, presence of
gingivitis and
periodontal disease
De Souza Rolim
et al. 2014 [24]Case-control 29 75.2 30 61.2
NINCDS-ADRDA for
AD, MMSE.
Orofacial pain, DMFT,
Gingival Bleeding
Index, probing pocket
depth, CAL, Plaque
Index
De Souza Rolim
et al. 2014 [39]Case-control 29 75.2 0 −
NINCDS-ADRDA for
AD, MMS Orofacial
pain, DMFT, Gingival
Bleeding Index,
probing pocket depth,
CAL, Plaque Index
Delwel et al.
2019 [53]Cross-sectional Dementia:303
MCI: 45 − −
MMS.
Presence of orofacial
pain using the
OPS-NVI and
self-reported pain,
number of missing or
restored teeth, coronal
and root caries,
retained roots, DPSI,
Plaque Index of
Silness and Loë, oral
hygiene, oral mucosal
lesions
Ellefsen et al.
2008 [54]Cross-sectional AD:61
OD:26
82.8
81.5 19 79.8
ICD-10.
Coronal caries, root
caries
Ellefsen et al.
2009 [26]Cohort AD:49
OD:15
83.6
81.3 13 79.9
ICD-10.
Number of present
teeth, DMFT, CCI,
NCI, ADJCI
Ellefsen et al.
2012 [55]Cross-sectional 61 82.8 0 −
Number of present
teeth, DMFT, coronal
caries, root caries
Elsig et al. 2013
[56]Cross-sectional 29 82.5 22 81.9
NPT, MMSE, CERAD,
CDR.
Number of present
teeth, presence of
visible dental plaque
Eshkoor et al.
2014 [57]Cross-sectional 1210 71.0 0 −
MMSE.
Presence of teeth or
dentures
Fjeld et al. 2014
[69]RCT 159 85.5 43 88.5
Evaluated by
physician.
Number of present
teeth, Simplified Oral
Hygiene Index,
mouth dryness
Furuta et al.
2013 [60]Cross-sectional 204 −82 −
CDR.
Number of present
teeth, dentures
Gil-Montoya et
al. 2016 [58]Cross-sectional
MiD:73
MoD:66
SeD:36
76.4
77.6
80.4
156 77.4
NINCDS-ADRDA.
Drug-induced
xerostomia
Int. J. Environ. Res. Public Health 2019,16, 4558 9 of 23
Table 5. Cont.
Study Design Dementia
Group Mean Age Control
Group Mean Age Dementia and Oral
Health Measure
Gil-Montoya et
al. 2017 [14]Case-control 133 80.0 324 79.8
DSM-IVR,
NINCDS-ADRDA.
Plaque Index,
Bleeding Index
Hatipoglu et al.
2011 [27]
Prospective-cohort
31 67.6 47 65.3
MMSE.
Dentures, DMFT, oral
hygiene status,
mucosal pathology
Hoben et al.
2016 [28]cohort 1606 85.0 1105 83.4
Chart.
Presence of debris, of
inflamed, swollen or
bleeding gums, oral
care by staff
Hoeksema et al.
2016 [19]Case-control 479 84.0 246 81.1
MMSE.
Visual plaque
according to the score
of Mombelli
Hopcraft et al.
2012 [61]Cross-sectional 510 ? 0 −
Chart.
Number of present
teeth, DMFT, coronal
caries, retained roots
Ide et al. 2016
[31]Cohort 59 77.6 0 −
NINCDS-ADRDA.
Presence of visible
plaque, bleeding on
probing, pocket depth,
presence of moderate
and severe
periodontal disease
(CDC/AAP criteria)
Jones et al. 1993
[29]Cohort 23 67.4 46 66.1
Longitudinal study of
dementia.
Present Teeth, CCI,
RCI
Kossioni et al.
2012 [40]Case-control 27 76.5 84 −
DSM-IV.
Number of present
teeth, DMFT, presence
of plaque or calculus,
mucosal pathology
Kossioni et al.
2013 [59]Cross-sectional 23 76.3 0 −
Mentally ill, including
dementia.
Mucosal complaints
Leal et al. 2010
[41]Case-control 20 69.6 20 68.3
NPT, CDR, MMSE.
Mucosal pathology,
salivary flow
Lee et al. 2013
[62]Cross-sectional 19 83.9 169 77.4
MCI, MiD, DSM-IV.
Missing teeth, coronal
and root caries,
periodontal pocket
depth, Plaque Index
Luo et al. 2015
[20]Cross-sectional 120 80.9 2389 70.0 DSM-IV.
Missing teeth
Minakuchi et al.
2006 [63]Cross-sectional 155 50
COD by MHLW JP.
Number of present
teeth, dentures
Nordenram et al.
1996 [42]Case-control 40 87.0 40 87.0
DSM-III-R, MMSE.
Number of present
teeth, dentures
Philip et al. 2012
[64]Cross-sectional 84 85.7 102 84.3
Chart, ADLOH.
DMFT, retained roots,
degree of gingival
inflammation, Plaque
Index
Int. J. Environ. Res. Public Health 2019,16, 4558 10 of 23
Table 5. Cont.
Study Design Dementia
Group Mean Age Control
Group Mean Age Dementia and Oral
Health Measure
Ribeiro et al.
2012 [65]Cross-sectional 30 79.1 30 67.8
ICD-10, DSM-IV,
MMSE, CDR.
Number of present
teeth, dentures,
DMFT, Oral Health
Index
Ship et al. 1994
[32]Cohort 21 64.0 21 65.0
NINCDS-ADRDA,
CT, MRI, PET, PT.
Number of present
teeth, DMFT, Change
in gingival status,
periodontal pocket
depth, salivary flow
Srilapanan et al.
2013 [66]Cross-sectional 69 75.5 0 −
Chart, MMSE.
Dental Habits,
number of present
teeth, dentures,
DMFT, caries,
Community
Periodontal Index,
need for oral care
Sumi et al. 2012
[33]Cohort 10 77.7 0 −
NINCD-ADRDA,
MMSE.
Number of present
teeth, DMFT, Gingival
Index, Plaque Index
Syrjala et al.
2012 [67]Cross-sectional 49 84.8 278 81.4
DSM-III-R, DSM-IV,
McKeith.
Number of present
teeth, dentures,
number of teeth with
periodontal pockets >
4 mm, presence of
poor oral hygiene
Warren et al.
1997 [43]Case-control 45 81.6 133 80.3
MMSE, chart, NT,
scans.
Number of present
teeth, dental habits,
coronal and root
caries, dentures,
modification of
Gingival Index,
modification of Debris
Index, xerostomia,
mucosal pathology
Zenthöfer et al.
2014 [36]Cohort 57 83.1 36 82.6
MMSE, chart.
Decayed and missing
teeth, periodontitis,
Gingival Bleeding
Index, CPITN, Dental
Hygiene Index,
Plaque Control
Record
Zenthöfer et al.
2016 [37]Cohort 33 81.7 60 83.4
MMSE, chart.
Missing teeth,
Gingival Bleeding
Index, CPITN, Plaque
Control Record,
mucosa pathology
Zenthöfer et al.
2016 [44]RCT 136 84.6 83 80.7
MMSE.
Gingival Bleeding
Index, CPITN
Int. J. Environ. Res. Public Health 2019,16, 4558 11 of 23
Table 5. Cont.
Study Design Dementia
Group Mean Age Control
Group Mean Age Dementia and Oral
Health Measure
Zenthöfer et al.
2017 [44]Case-control 136 84.6 83 80.7
MMSE.
Gingival Bleeding
Index, CPITN
ADJCI: adjusted caries increment; CAL: clinical attachment level; CCI: crude caries increment; CDC/AAP: Center
for Disease Control/American Academy of Periodontology; COD: classification of dementia; CPITN: community
periodontal index of treatment needs CT: computer tomography; DMFT: decayed missing filled teeth; DPSI: Dutch
Periodontal Screening Index; ICD: International Classification of Disease; MCI: Mild Cognitive Impairment; Mckeith:
Consensus criteria presented by McKeith; MDS-COGS: Minimum Data Set Cognition Scale; MHLW: Ministry of
Health, Labour and Welfare; MMSE: Mini Mental State Examination; MRI: magnetic resonance imaging; NCI: net
caries increment NINCDS-ADRDA: National Institute of Neurological Disorders and Stroke Alzheimer’s Disease and
Related Disorders Association; NHR: nursing home residents; NPT: Neuropsychological testing; NT: Neurological
testing; OPS-NVI: ORrofacial Pain Scale for Nonverbal Individuals; PET. Positron emission tomography.
Table 6. List of studies about the relationship between dementia and periodontal disease.
Study Design
Dementia or
Periodontal
Disease Group
Mean Age Control
Group Mean Age
Dementia and Oral
Periodontal Disease
Measure:
Dintica et al.
2018 [25]Cohort Free D: 2715 − − Dementia incidence:
DSM-IV, MMSE.
Ide et al. 2016
[31]Cohort
Mid to Mod: 60
30 men
30 women
77.7 − −
Presence or absence of
periodontal disease
following CDC/AAP
Kato et al. 2019
[30]Cohort
210
Men: 103
Women: 107
78.1 +−4.9 − −
Cochran-Armitage
trend test
Mann-Whitney U test
Kruskal-Wallis test
Spearman’s rank
correlation test
Student’s t-test
Lee et al. 2017
[10]Cohort PD: 3028 (54%
male) 72.4
No PD:
3028
(54% male)
72.4
Dementia incidence:
ICD-9-CM codes
523.3–5
Takeuchi et al.
2017 [34]Cohort
PD: 1566 (691
men and 875
women)
−−−
Dementia incidence:
DSM-III, MMSE,
HDS-R.
Tiisanoja et al.
2018 [68]Cross-sectional IG: 170
80.9
AD: 82.2
OD: 82.5
− −
DSM-IV, McKeith et
al. MMSE.
Structured oral
examination
examining number of
teeth with periodontal
pocket depth of 4 mm
or more
Yoo et al. 2019
[35]Cohort TE: 104,903 −NE:
104,903 −
Dementia incidence:
Disease codes and
definition codes
associated with
dementia
AD: Alzheimer’s disease; CDC/AAP: Centre for Disease Control/American Academy of Periodontology; FreeD:
Free-dementia; DI: Dementia incidence; HDS-R: Revised Hasegawa’s Dementia Scale; IG: Intervention Group; Mid
to Mod: mild to moderate dementia; OD: other dementia; PD: Periodontal Disease; NHANES: National Health and
Nutrition Examination Survey; NE: non-extraction cohort; TE: tooth extraction.
3.2. Results of Individual Studies
The number of present teeth was one of the most used measures for assessing oral health. In
particular, from the included studies it came to light that the range within the two groups varied
between 2.0 to 20. 2 for people without dementia and between 1.7 to 20.5 for people with dementia.
According to Delwel et al. [
53
], the number of present teeth was lower in the participants with dementia
(median =2.0, IQR =0.0–18.0) than in people with MCI (median =18.0, IQR =5.5–24.0). However, this
study underlined that, if only dentate participants were considered, no significant differences were
recorded between the two groups (median =18.0, IQR =9.0-24-0) (Table 7). The review showed that
Int. J. Environ. Res. Public Health 2019,16, 4558 12 of 23
coronal and root caries were more common in people with dementia that in people without dementia:
coronal caries varied between 0.1–2.9 [
43
,
54
,
55
] and 0.0-1-0, respectively [
21
,
54
], and root caries varied
between 0.6–4.9 [
43
,
54
,
55
] in participants with dementia and 0.3–1.7 [
13
,
54
,
55
] in normal cognitive
participants. For retained roots, the range was between 0.0–1.2 [
54
] in people without dementia and
between 0.2–10 [
21
,
54
] in people with dementia. Moreover, Delwel et al. [
53
] demonstrated that dentate
participants with dementia had more coronal caries (median =1.0, IQR =0.0–2.0), root caries, and
retained roots (median =0.0, IQR =0.0–1.0) than dentate people with MCI (Table 8. With regards to the
DMFT Index (Table 9), the lowest one was 14.9 in the study by Srilapanan et al. In general, the DMFT
index did not show a significant difference within the two groups (19.7–26.1 in healthy people and
14.9–28.0 in people with dementia), except for one study, which demonstrated that the DMFT Index
was 25.5 in people without dementia and 28.0 in people with dementia.
Most of the participants with dementia presented gingival bleeding or inflammation [
23
,
48
]
(Table 10). According to De Souza [
24
], the Gingival Bleeding Index was 46.0% in the elderly with
dementia and periodontal infections were most common in the latter (58.6%) than in normal cognitive
participants (26.7%). 73.8% of the Delwel et al. [
53
] study included patients had periodontal pockets of
≥
4 mm, 18.8% of them had one or more teeth with mobility grade 2, and 5.8% had one or more teeth
with mobility grade 3.
Table 7. Results about the number of present teeth.
Study Number of Present
Teeth No Dementia
Number of Present
Teeth Dementia
pValue: Dementia
vs. No Dementia
Bomfin et al. 2013 [46] 2.0 3.0 −
Chalmers et al. 2002, 2003
[13,21,47]17.2 18.0 >0.05
Chapman et al. 1991 [48] - 12.8 −
Chen et al. 2010 [23] - 18.2 community living
19.3 assisted living -
Delwel et al. 2019 [53] - Dementia:18.0
MCI: 22.0 0.058
Ellefsen et al. 2009 [26] 20.2 17.3 AD
16.1 OD ≤0.001
Ellefsen et al. 2012 [55] - 16.5 -
Elsig et al. 2013 [56] 6.5 4.9 0.533
Fjeld et al. 2013 [69] 20.1 20.0 -
Hopcraft et al. 2012 [61] 14.6 0.7 >0.05
Jones et al. 1993 [29] 18.2 17.9 0.90
Kossioni et al. 2012 [40] - 4.4 -
Ribeiro et al. 2012 [65] Median 13.5 (0.0-28-0) Median 1.0 (o.o-22-0) 0.0004
Srisilapanan et al. 2013 [
66
]
- 19.5 -
Sumi et al. 2012 [33] - 12.7 -
Syrjala et al. 2012 [67] 15.0
10.9 AD
7.8 VaD
1.7 OD
-
Warren et al. 1997 [43] 13.0 10.0 AD
13.0 OD p>0.05
AD: Alzheimer dementia; OD: other dementia; Vad: vascular dementia.
Int. J. Environ. Res. Public Health 2019,16, 4558 13 of 23
Table 8. Results about coronal/root caries and retained roots.
Study
Coronal
Caries No
Dementia
Coronal
Caries
Dementia
Root caries
no
Dementia
Root Caries
Dementia
Retained
Roots no
Dementia
Retained Root
Dementia
Chalmers et al.
2002–2003 [13,47]0.0 * * 0 ** 5 0.3 0.8 Decayed: 0.0 *
Sound: 0.1
Decayed: 0.3 *
Sound: 0.1
De Souza Rolim et al.
2014 [24,39]3.4% 6.8% - - 10.2% 6.8%
Delwel et al. 2019 [53] - 27.0% - 19.0% - 18.1%
Ellefsen et al. 2008–2012
[54,55]1.0 * 2.9 * 1.7 * 4.9 * AD
2.3 * OD 0.0 AD 10.0 *
OD 0.5 *
Jones et al. 1993 [29] 0.8 1.4 0.4 1.8 - -
Lee et al. 2013 [62] 0.8 1.0 0.5 * 1.8 * - -
Philip et al. 2012 [64] - - - - 1.2 1.8
Warren et al. 1997 [43] 0.4 AD 0.1
OD 0.4 0.8 AD O.6
OD 0.6 - -
AD: Alzheimer’s disease; OD: other dementia; *: p≤0.05; **: p≤0.01.
Table 9. Results about the DMFT Index.
Study DMFT No Dementia DMFT Dementia
Adam et al. 2006 [45]
Decayed 1.1
Missing 28.2
Filled 0.7
Decayed 0.80
Missing 27.3
Filled 0.90
Chalmers et al. 2002 [21,47]
Decayed 0.0–0.4
Missing -
Filled 24.7–25.7
Decayed 0.5–1.6 *
Missing -
Filled 22.1–23.9
Chalmers et al. 2003 [13]
Decayed 0.0–0.1
Missing -
Filled -
Decayed 0.3–1.3 *
Missing -
Filled -
Chapman et al. 1991 [48]
Decayed -
Missing -
Filled -
Decayed 1.4
Missing 17.8
Filled 6.4
DMFT 25.6
Chen et al. 2013 [49,50]
Decayed -
Missing -
Filled -
Decayed 5.5 (C), 5.3 (A), 6.0 (NHR)
Missing -
Filled 10.4 (C), 10.9 (A), 8.7 (NHR)
Chu et al. 2015 [38]
Decayed 0.8
Missing 18.3
Filled 2.4
DMFT 21.5
Decayed 1.2
Missing 18.9
Filled 2.5
DMFT 22.3
De Souza Rolim et al. 2014 [24,39]
Decayed -
Missing -
Filled -
Decayed -
Missing -
Filled -
DMFT 27.2 Range 11–32
Hatipoglu et al. 2011 [27]
Decayed
Missing
Filled
DMFT 19.7
Decayed
Missing
Filled
DMFT 24.2
Hopcraft et al. 2012 [61]
Decayed 2.9
Missing 17.4
Filled 4.8
DMFT 25.0
Decayed 2.4
Missing 17.9
Filled 4.8
DMFT 25.0
Int. J. Environ. Res. Public Health 2019,16, 4558 14 of 23
Table 9. Cont.
Study DMFT No Dementia DMFT Dementia
Kossioni et al. 2012 [40]
Decayed -
Missing -
Filled -
Decayed 1.8
Missing -
Filled 0.9
Lee et al. 2013 [62]
Decayed CC+RC
Missing 12.7
Filled -
Decayed CC+RC
Missing 10.2
Filled -
Luo et al. 2015 [20]
Decayed -
Missing 9.3
Filled -
Decayed -
Missing 18.7 **
Filled -
Philip et al. 2012 [64]
Decayed 2.9
Missing 18.0
Filled 5.0
DMFT 26.1
Decayed 3.0
Missing 17.4
Filled 5.3
DMFT 25.9
Ribeiro et al. 2012 [65]
Decayed
Missing
Filled
DMFT 25.5 *
Decayed
Missing
Filled
DMFT 28.0 *
Srisilapanan et al. 2013 [66]
Decayed -
Missing -
Filled -
Decayed 1.5
Missing 12.6
Filled 0.8
DMFT 14.9
Zenthöfer et al. 2014 [36]
Decayed 0.7
Missing 19.9
Filled -
Decayed 0.6
Missing 20.8
Filled -
Zenthöfer et al. 2016 [37]
Decayed -
Missing 20.5
Filled -
Decayed -
Missing 20.5
Filled -
CC: coronal caries; DMFT: decayed missing filled teeth; NHR: nursing homes residents; RC: root caries; *: p
≤
0.05;
**: p≤0.01.
Table 10. Results about gingival and periodontal disease.
Study Outcome Measure Gingival Health No
Dementia
Gingival Health
Dementia
Chen et al. 2010 [23]
Calculus/plaque/gingival
bleeding
No: 1.2%
M to M: 85.5%
High: 13.3%
No: 0.9%
M to M: 67.9%
High: 31.3%
Chen et al. 2013 [49]
Calculus/plaque/gingival
bleeding -
C: 0% No, 65.8% Small,
34.2 High
A: 8.3% No, 66.7% Small,
25.0% High
NHR: 59.2% No, 59.2%
Small, 40.5% High
Chen et al. 2013 [50]
Calculus/plaque/gingival
bleeding
No:0.0%
M to M: 73.8% **
High: 26.2%
No: 0.3%
M to M: 59.2%
High:40.4%
Chu et al. 2015 [38]Community Periodontal
Index, pockets ≥3 mm 74.0% 78.0%
Cohen-Mansfield et al.
2002 [52]
Periodontal disease
Gingivitis −44.4%
38.9%
Int. J. Environ. Res. Public Health 2019,16, 4558 15 of 23
Table 10. Cont.
Study Outcome Measure Gingival Health No
Dementia
Gingival Health
Dementia
De Souza Rolim et al.
2014 [24]
Probing pocket depth
(mm)
Gingivitis
MoD-SeV periodontitis
Periodontal infection
Gingival Bleeding Index
-
10.0%-10.0%
6.7%
26.7%
-
1.6 mm
31.0%
6.9%–20.7%
58.6 **
46.0%
De Souza Rolim et al.
2014 [39]
Probing pocket depth
(mm)
Gingivitis
MoD-SeV periodontitis
Periodontal infection
Gingival Bleeding Index
-
10.0%-10.0%
6.7%
26.7%
-
1.6 mm
31.0%
6.9%–20.7%
58.6 **
46.0%
Delwel et al. 2019 [53]
Silness and Loë Plaque
Index
DPSI
Probing pocket depth
(mm)
Mobility grade
2.0
3- (IQR =2.4)
≥4 mm in 73.8%
participants
Grade 2 in18.8%
Grade 3 in 5.8%
Gil-Montoya et al. 2016
[58]Bleeding Index 50.6 67.5 ***
Hoben et al. 2016 [28]Inflamed, swollen or
bleeding gums 1.2% 0.8%
Hopcraft et al. 2012 [61]
Periodontal pocket depth
4 mm, periodontal
pocket depth >6 mm
35.0% 36.0%
Ide et al. 2016 [31]
Probing depth >3 mm
Bleeding on probing
Periodontitis according
to CDC/AAP criteria:
MoD-SeV
6.7%
13.6%
37.3
25.4%–1.9%
Lee et al. 2013 [62]
Periodontal pocket depth
1.5 mm 1.4 mm
Philip et al. 2012 [64]
Gingival inflammation:
Minimal:
Light:
Moderate:
22.5%
36.3%
32.5%
6.8%
13.0%
21.0%
56.5%
13.0%
Sumi et al. 2012 [33]Gingival Index
Loe-Silness - 1.2
Srisilapanan et al. 2013
[66]
Community Periodontal
Index, highest score:
Normal
Bleeding
Calculus
Pocket depth 4–5 mm
Pocket depth ≥6 mm
-
-
-
-
-
9.4%
1.9%
34.0%
30.2%
24.5%
Syrjala et al. 2012 [67]Number of teeth with
periodontal pockets
2.8 AD
2.8 VaD
1.7 OD
Warren et al. 1997 [43]
Modified version of
Gingival Index by Silness
and Loe
0.7 1.1 AD
1.2 0.9 OD
Zenthöfer et al. 2014 [
36
]
Periodontitis
Gingival Bleeding Index
Community periodontal
index of treatment needs
73.9%
40.9%
2.8
100% ***
43.8%
3.4 ***
Int. J. Environ. Res. Public Health 2019,16, 4558 16 of 23
Table 10. Cont.
Study Outcome Measure Gingival Health No
Dementia
Gingival Health
Dementia
Zenthöfer et al. 2016 [
37
]
Gingival Bleeding Index
Community periodontal
index of treatment needs
38.1%
3.1
52.1% *
3.3
Zenthöfer et al. 2016 [
44
]
Community periodontal
index of treatment needs 2.7 3.1 ***
Zenthöfer et al. 2017 [
44
]
Gingival Bleeding Index
Community periodontal
index of treatment needs
48.8%
2.7
53.8%
3.1 ***
AD: Alzheimer’s disease; Vad: vascular dementia; OD: other dementia; *: p≤0.05; **: p≤0.01; ***: p≤0.00.
Zenthöfer [
36
,
37
,
44
] demonstrated that the Gingival Bleeding Index of people with dementia
was 43.8 to 53.8% and confirmed De Souza’s results, proving that people with dementia suffer from
periodontitis more than people without dementia (community periodontal index of treatment needs
was 3.1–3.4 in dementia people and 2.7–2.8 in non dementia people [36,37]).
Nine of the included studies found no significant differences between both groups with regards
to oral hygiene [
21
,
22
,
27
,
45
,
61
,
62
,
64
–
67
] and five studies demonstrated a higher level of plaque in
dementia people [
14
,
36
,
43
,
56
,
65
]. The Plaque Index by Silness and Loe was 0.7 in the study by Chalmers
et al. [
13
], 2.5 in the study by Gil-Montoya [
14
] in the elderly with dementia, and 2.0 in the study by
Delwel et al. [
53
]. Sumi et al. [
33
] showed a Plaque Index by Quigley and Hein of 1.6. O’Leary Plaque
Index was significantly higher in dementia people (90.1%) than in non dementia people [
36
] (73.3%).
Finally, Ribeiro [
65
] et al. established that the Oral Hygiene Index by Green and Vermillion is higher in
participants with dementia (4.5) than in participants without dementia (2.2). A significantly higher
Debris Index in people with moderate to severe dementia was found [43].
Furthermore, edentuloussnes was a condition that affected a large percentage of the elderly,
in particular 11.6 to 72.7% of the elderly with dementia [
66
,
67
] and 14.0 to 70% of the elderly without
dementia [
38
,
45
]. Within partially or totally edentulous participants, denture utilization varied between
these percentages: 17.0–81.8% in normal cognitive people and 5.0 to 100% in people with cognitive
impairment [27,31] (Table 11).
Table 11. Results about dentures and edentulousness.
Study Dentures no
Dementia
Dentures
Dementia
Edentulousness
No Dementia
Edentulousness
Dementia
Adam et al. 2006 [45]/ / 70.0% 63.0%
Bomfim et al. 2013 [46] 20.0% 20.0% 46.7% 40.0%
Chalmers et al. 2003 [13] 27.6–30.1% 20.7–23.3% / /
Chapman et al. 1991 [48] - 59.0% - 64.7%
Chen et al. 2013 [49] -
48.0% C
38.9% A
47.1% NHR
/ /
Chu et al. 2015 [38] 14.0% 17.0% / /
De Souza Rolim et al.
2014 [24]43.3% 25.8% 43.3% 32.3%
Elsig et al. 2013 [56]/ / 54.6% 62.1%
Eshkoor et al. 2014 [57] 81.8% 86.2% / /
Hatipoglu et al. 2011 [27]57.0% Max
55.0% Mand
97.0% Max
100.0% Mand / /
Int. J. Environ. Res. Public Health 2019,16, 4558 17 of 23
Table 11. Cont.
Study Dentures no
Dementia
Dentures
Dementia
Edentulousness
No Dementia
Edentulousness
Dementia
Kossioni et al. 2012 [40] - 62.9%
Nordenram et al. 1996 [
42
]
17.0% 7.0% Mod
5.0% Sed 43.0% 36.0% MoD
45.0% SeD
Ship et al. 1994 [32] 43.0% 40.0-67.0% / /
Srisilapapanan et al.
2013 [66]- 40.6% - 11.6%
Syrjala et al. 2012 [67] 73.7%
75.5% AD
68.6% VaD
72.2% OD
44.6%
63.3% AD
68.8% VaD
72.7% OD
Warren et al. 1997 [43]/ / 31.6% 40.0% AD
32.0% OD
Mand. Mandibular; Max: Maxillary; MoD: moderate dementia; NHR: nursing home residents; SeD: severe dementia;
Vad: vascular dementia; OD: other dementia; *: p<0.05.
Data about orofacial pain were extracted from seven of the included studies [
13
,
24
,
39
,
40
,
45
,
52
].
The percentage of the elderly with dementia suffering from orofacial pain was higher than that of
participants without dementia: 7.4 to 21.7%, 6.7 to 18.5%, respectively. The cross-sectional study by
Delwel et al. [
53
] carefully examined the presence of orofacial pain in the elderly with dementia or
MCI, while using the OPS-NVI [
12
] and self reported pain. The OPS-NVI was 4% in rest, 10% during
drinking, 19% during chewing, and 22% during oral hygiene care. Pain reported by participants with
dementia or MCI was 25.7% overall (Table 12).
Table 12. Results about Orofacial pain.
Study Orofacial Pain No Dementia Orofacial Pain Dementia
Adam et al. 2006 [45] 18.5% 7.4%
Chalmers et al. 2003 [13] 11.2–11.5% 18.4–19.0%
Cohen-Mansfield et al. 2002 [52]−60.0%
De Souza Rolim et al. 2014 [24] 6.7% 20.7%
Delwel et al. 2019 [53]−Dementia: 27.4%
MCI: 20.5%
Kossioni et al. 2012 [40]−21.7%
MCI: Mild Cognitive Impairment.
The feeling of a dry mouth or xerostomia reached the percentages of 22.0% in people with dementia
and 8.4% in people without dementia [
33
] and it was present in 9.1–45% of the cases and 8.4–20.0% of
the controls [
40
–
43
]. Gil-Montoya [
58
] showed a more drug-induced xerostomia in cases (68.5–72.2%)
than in the controls (36.5%).
Oral pathology, such as stomatitis and candidiasis, was most common in the cases than in
controls. Chu et al. [
38
] and other authors [
24
,
39
,
41
] reported a percentage of candidiasis of 3.6–30%
for cases and 0.0–5.0% for controls. Furthermore, 18.1–59.1% of cases and 0.0–7.4% of controls showed
stomatitis [13,27,40].
In conclusion, with regards to the oral care need, the included studies [
13
,
47
,
49
,
50
,
61
,
64
,
67
]
reported a need of 21% for cleaning teeth and dentures in the elderly with dementia. Chalmers
et al. [
47
] demonstrated that, with an increasing severity of cognitive impairment, there is also an
increase of oral care need: the assistance need for cleaning teeth and dentures in severe dementia was
100.0%, as compared to the assistance need in moderate dementia, which was 57.2% (teeth) and 97.3%
Int. J. Environ. Res. Public Health 2019,16, 4558 18 of 23
(dentures). Regarding periodontal disease (Table 13), Dintica et al. [
25
] and Ide et al. [
31
] found that the
mean change (decrease) in MMSE score due to tooth loss was, respectively,
−
0.94 to 0.37 (nine months
follow-up, adjusted for age, sex, and education) and
−
3.6 to
−
0.03 (six months follow-up), establishing
a significant association between tooth loss and the progression of cognitive impairment. The crude
hazard ratio of dementia according to the number of remaining/lost teeth was 1.6 [
10
,
34
]. Tiisanoja
et al. [
68
] demonstrated that subjects with pocket depth
≥
4 mm had an increased, but not statistically
significant, risk of developing Alzheimer’s Disease (Relative risk: 1.54). Furthermore, Yoo et al. [
35
]
demonstrated that periodontal treatment lead to a significant decrease in the incidence of dementia.
The prospective community-based study by Kato et al. [
30
] showed that the number of natural teeth
was significantly associated with an individual’s MMSE score: the percentage of cognitively normal
subjects (MMSE scores: 27–30) significantly decreased with a decrease in the number of natural teeth
(number of teeth =5–9, percentage of participants without cognitive impairment =26.7%; number of
teeth =15–19; and, percentage of normal cognitive participants =44.8%). Kato et al. also demonstrated
that the use of artificial teeth was associated with cognitive function preservation.
Table 13. Association between periodontal disease and dementia.
Study Follow-Up Period Association between Tooth Loss/Periodontal
Disease and Dementia
Dintica et al. 2018 [25] 9 years Annual mean change in MMSE by tooth loss:
−0.94 to −0.37 *
Ide et al. 2016 [31] 6 months Mean change in MMSE by the presence of
periodontal disease:
−
3.6 to
−
0.03
−
3.6 to 0.04 ***
Kato et al. 2019 [30] 4 years
Cochran-Armitage trend test Mann-Whitney U
test Kruskal-Wallis test Spearman’s rank
correlation test Student’s t-test
Lee et al. 2017 [10]
Index date: date of the first
periodontal disease diagnosis.
Patients were followed until
dementia diagnosis, death,
withdrawal from the NHI or
December 31, 2012
Hazard ratio of having dementia in persons with
periodontal disease →
HR:
1.02–1.32
1.01–1.32 **
Takeuchi et al. 2017 [34] 5 years
Hazard ratio of having dementia in persons with
10-19 remaining teeth →
HR:
1.45–3.03
1.06–2.46 ***
Tiisanoja et al. 2018 [68]
Risk of having AD in persons with pocket depth
≥4 mm →
RR: 1.54
Yoo et al. 2019 [35] 7 year
Odds Ratio of having dementia in persons with
7–12 teeth lost →
OR: 1.272
HR: hazard ratio; *: adjusted for age, sex and education; **: adjusted for sociodemographic characteristics and
comorbidities; ***: adjusted for baseline age, gender and cognitive score; NE: non-extraction cohort; NHI: National
Health Insurance; OR: odds ratio; RR: relative risk; TE: tooth extraction.
4. Discussion
The purpose of this systematic review was to examine studies regarding oral health in the
elderly with and without dementia and to investigate the relationship between periodontal status
and dementia. As reported in a recent review by Delwel et al. [
75
], the analysis of this study showed
no significant differences between the case and controls with regards to the number of present
teeth [
13
,
21
,
29
,
43
,
53
,
56
,
61
,
67
,
69
] and to the DMFT Index [
27
,
38
,
61
,
65
]. However, the DMFT categories
separately, “decay”, “missing”, and “filled”, give a better indication of disease and treatment need
compared to the index, which reports dental caries history as a whole. Coronal and root caries and
Int. J. Environ. Res. Public Health 2019,16, 4558 19 of 23
retained roots are most common in people with dementia [
21
,
56
,
65
], and this condition might be
explained by cognitive and behavioral deterioration, which reduced the ability to perform routine oral
care [
76
]. In the elderly with dementia saliva flow rates decreases [
32
], eating habits change (more
cariogenic food) [
51
,
56
,
61
,
77
], and motor skills and coordination worsen [
65
], which leads to a lower
chewing and swallowing efficiency [56,77].
Another important point to be considered is the oppositional and aggressive behavior towards
oral care and decreased communication skills, which represent barriers to oral hygiene and assistance.
These obstacles could be overcome by performing oral care education to caregivers and by increasing
dental checks of the elderly with dementia [62,78,79].
Moreover, the recent observational study by Delwel et al. [
53
] recorded a significant correlation
between the cognitive impairment level and the number of present/missing/restored teeth and retained
roots, which suggests that dementia could have a negative impact on oral health.
Concerning oral soft tissues, this study confirmed Delwel’s et al. review results [
80
]: gingival
bleeding, periodontal disease, mucosal lesions, and xerostomia were found at higher rates in participants
with cognitive impairment. Dry mouth was more common in the elderly, who used medication or had
radiotherapy history (head and neck) or autoimmune disease [32].
Approximately the same percentage of the elderly either with or without dementia wore
dentures [
13
,
42
]. However, people with an advanced dementia degree showed a lower use of
dentures, as compared to people with moderate dementia, because of the musculature, salivary flow
decrease, and lower tolerance of dentures.
The deterioration of verbal communication skills and the higher prevalence of oral disease might
cause a higher suffering to people with dementia, due to orofacial pain [
45
,
50
,
52
,
53
]. In this systematic
review, the new information included concern the potential role of periodontal disease as a risk factor
for developing cognitive impairment. In fact, all of the studies included in Table 10 demonstrated an
association between teeth loss due to periodontal disease and the onset of dementia [
10
,
25
,
30
,
31
,
34
,
35
,
60
].
This association is based on biological mechanisms: subjects with periodontal disease or antibodies
to periodontal bacterial flora show an increased systemic proinflammatory state, which lead to an
increase of the cognitive decline rate [
31
]. According to Yoo et al., the more teeth are lost, the higher
incidence of dementia is. The author also stated that monitoring cognitive status in patients with
extensive teeth loss could lead to an early diagnosis of dementia. The significant association between
the number of natural teeth and the MMSE score was also confirmed in the study by Kato et al., which
suggest that the use of artificial teeth could help to preserve the cognitive function.
Strengths and Limitations
The most important limitation of this study is the result of the quality assessment of the articles,
since more than half of the included studies have a score equal or below 5. The number of high quality
studies was low and no homogeneity can be found. For this reason, it was impossible to perform
a meta-analysis. In the included studies, several different measures were used to evaluate oral health
status and some studies did not distinguish between the elderly with and without dementia.
The main strength of this review is the systematic approach and involvement of a multidisciplinary
team (dentists, neuropsychologist, pain specialist). In addition, in almost all of the studies reviewed,
oral examinations are structured and standardized, and were carried out by dentists.
5. Conclusions
The elderly with dementia show a higher level of plaque, coronal and root caries, retained roots,
gingival, and periodontal disease. Further attention is needed regarding orofacial pain, which is very
common in dementia people. Poor oral health within this group could be increased by the reduction of
submandibular salivary flow, deterioration of cognitive functions, motor and communication skills,
and aggressive behavior. Caregivers should be educated and dentist’s checks in nursing homes should
be enhanced in order to improve the oral health status of the elderly with dementia. Our contribution
Int. J. Environ. Res. Public Health 2019,16, 4558 20 of 23
highlights the relationship between periodontal disease and dementia. Teeth loss due to periodontal
disease increases the risk of cognitive function deterioration. However, the specific mechanisms of this
association need further investigation.
Author Contributions:
Conceptualization, D.L. and G.M.; methodology, F.D.V.; validation A.L. and F.C.;
formal analysis, D.D.S.; investigation, G.M.; data curation, D.L.; writing—original draft preparation, G.M.;
writing—review and editing, D.L.; visualization, F.C.; supervision, M.P.
Funding: This research received no external funding.
Conflicts of Interest: The authors declare no conflict of interest.
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